/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2005 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. * * tcp.c, Code implementing the TCP protocol. */ #pragma ident "%Z%%M% %I% %E% SMI" #include #include #include #include #include #include #include #include #include #include #include #include #include "ipv4.h" #include "ipv4_impl.h" #include "mac.h" #include "mac_impl.h" #include "v4_sum_impl.h" #include #include "tcp_inet.h" #include "tcp_sack.h" #include #include /* * We need to redefine BUMP_MIB/UPDATE_MIB to not have DTrace probes. */ #undef BUMP_MIB #define BUMP_MIB(x) (x)++ #undef UPDATE_MIB #define UPDATE_MIB(x, y) x += y /* * MIB-2 stuff for SNMP */ mib2_tcp_t tcp_mib; /* SNMP fixed size info */ /* The TCP mib does not include the following errors. */ static uint_t tcp_cksum_errors; static uint_t tcp_drops; /* Macros for timestamp comparisons */ #define TSTMP_GEQ(a, b) ((int32_t)((a)-(b)) >= 0) #define TSTMP_LT(a, b) ((int32_t)((a)-(b)) < 0) /* * Parameters for TCP Initial Send Sequence number (ISS) generation. * The ISS is calculated by adding three components: a time component * which grows by 1 every 4096 nanoseconds (versus every 4 microseconds * suggested by RFC 793, page 27); * a per-connection component which grows by 125000 for every new connection; * and an "extra" component that grows by a random amount centered * approximately on 64000. This causes the the ISS generator to cycle every * 4.89 hours if no TCP connections are made, and faster if connections are * made. */ #define ISS_INCR 250000 #define ISS_NSEC_SHT 0 static uint32_t tcp_iss_incr_extra; /* Incremented for each connection */ #define TCP_XMIT_LOWATER 4096 #define TCP_XMIT_HIWATER 49152 #define TCP_RECV_LOWATER 2048 #define TCP_RECV_HIWATER 49152 /* * PAWS needs a timer for 24 days. This is the number of ms in 24 days */ #define PAWS_TIMEOUT ((uint32_t)(24*24*60*60*1000)) /* * TCP options struct returned from tcp_parse_options. */ typedef struct tcp_opt_s { uint32_t tcp_opt_mss; uint32_t tcp_opt_wscale; uint32_t tcp_opt_ts_val; uint32_t tcp_opt_ts_ecr; tcp_t *tcp; } tcp_opt_t; /* * RFC1323-recommended phrasing of TSTAMP option, for easier parsing */ #ifdef _BIG_ENDIAN #define TCPOPT_NOP_NOP_TSTAMP ((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | \ (TCPOPT_TSTAMP << 8) | 10) #else #define TCPOPT_NOP_NOP_TSTAMP ((10 << 24) | (TCPOPT_TSTAMP << 16) | \ (TCPOPT_NOP << 8) | TCPOPT_NOP) #endif /* * Flags returned from tcp_parse_options. */ #define TCP_OPT_MSS_PRESENT 1 #define TCP_OPT_WSCALE_PRESENT 2 #define TCP_OPT_TSTAMP_PRESENT 4 #define TCP_OPT_SACK_OK_PRESENT 8 #define TCP_OPT_SACK_PRESENT 16 /* TCP option length */ #define TCPOPT_NOP_LEN 1 #define TCPOPT_MAXSEG_LEN 4 #define TCPOPT_WS_LEN 3 #define TCPOPT_REAL_WS_LEN (TCPOPT_WS_LEN+1) #define TCPOPT_TSTAMP_LEN 10 #define TCPOPT_REAL_TS_LEN (TCPOPT_TSTAMP_LEN+2) #define TCPOPT_SACK_OK_LEN 2 #define TCPOPT_REAL_SACK_OK_LEN (TCPOPT_SACK_OK_LEN+2) #define TCPOPT_REAL_SACK_LEN 4 #define TCPOPT_MAX_SACK_LEN 36 #define TCPOPT_HEADER_LEN 2 /* TCP cwnd burst factor. */ #define TCP_CWND_INFINITE 65535 #define TCP_CWND_SS 3 #define TCP_CWND_NORMAL 5 /* Named Dispatch Parameter Management Structure */ typedef struct tcpparam_s { uint32_t tcp_param_min; uint32_t tcp_param_max; uint32_t tcp_param_val; char *tcp_param_name; } tcpparam_t; /* Max size IP datagram is 64k - 1 */ #define TCP_MSS_MAX_IPV4 (IP_MAXPACKET - (sizeof (struct ip) + \ sizeof (tcph_t))) /* Max of the above */ #define TCP_MSS_MAX TCP_MSS_MAX_IPV4 /* Largest TCP port number */ #define TCP_MAX_PORT (64 * 1024 - 1) /* Round up the value to the nearest mss. */ #define MSS_ROUNDUP(value, mss) ((((value) - 1) / (mss) + 1) * (mss)) #define MS 1L #define SECONDS (1000 * MS) #define MINUTES (60 * SECONDS) #define HOURS (60 * MINUTES) #define DAYS (24 * HOURS) /* All NDD params in the core TCP became static variables. */ static int tcp_time_wait_interval = 1 * MINUTES; static int tcp_conn_req_max_q = 128; static int tcp_conn_req_max_q0 = 1024; static int tcp_conn_req_min = 1; static int tcp_conn_grace_period = 0 * SECONDS; static int tcp_cwnd_max_ = 1024 * 1024; static int tcp_smallest_nonpriv_port = 1024; static int tcp_ip_abort_cinterval = 3 * MINUTES; static int tcp_ip_abort_linterval = 3 * MINUTES; static int tcp_ip_abort_interval = 8 * MINUTES; static int tcp_ip_notify_cinterval = 10 * SECONDS; static int tcp_ip_notify_interval = 10 * SECONDS; static int tcp_ipv4_ttl = 64; static int tcp_mss_def_ipv4 = 536; static int tcp_mss_max_ipv4 = TCP_MSS_MAX_IPV4; static int tcp_mss_min = 108; static int tcp_naglim_def = (4*1024)-1; static int tcp_rexmit_interval_initial = 3 * SECONDS; static int tcp_rexmit_interval_max = 60 * SECONDS; static int tcp_rexmit_interval_min = 400 * MS; static int tcp_dupack_fast_retransmit = 3; static int tcp_smallest_anon_port = 32 * 1024; static int tcp_largest_anon_port = TCP_MAX_PORT; static int tcp_xmit_lowat = TCP_XMIT_LOWATER; static int tcp_recv_hiwat_minmss = 4; static int tcp_fin_wait_2_flush_interval = 1 * MINUTES; static int tcp_max_buf = 1024 * 1024; static int tcp_wscale_always = 1; static int tcp_tstamp_always = 1; static int tcp_tstamp_if_wscale = 1; static int tcp_rexmit_interval_extra = 0; static int tcp_slow_start_after_idle = 2; static int tcp_slow_start_initial = 2; static int tcp_sack_permitted = 2; static int tcp_ecn_permitted = 2; /* Extra room to fit in headers. */ static uint_t tcp_wroff_xtra; /* Hint for next port to try. */ static in_port_t tcp_next_port_to_try = 32*1024; /* * Figure out the value of window scale opton. Note that the rwnd is * ASSUMED to be rounded up to the nearest MSS before the calculation. * We cannot find the scale value and then do a round up of tcp_rwnd * because the scale value may not be correct after that. */ #define SET_WS_VALUE(tcp) \ { \ int i; \ uint32_t rwnd = (tcp)->tcp_rwnd; \ for (i = 0; rwnd > TCP_MAXWIN && i < TCP_MAX_WINSHIFT; \ i++, rwnd >>= 1) \ ; \ (tcp)->tcp_rcv_ws = i; \ } /* * Set ECN capable transport (ECT) code point in IP header. * * Note that there are 2 ECT code points '01' and '10', which are called * ECT(1) and ECT(0) respectively. Here we follow the original ECT code * point ECT(0) for TCP as described in RFC 2481. */ #define SET_ECT(tcp, iph) \ if ((tcp)->tcp_ipversion == IPV4_VERSION) { \ /* We need to clear the code point first. */ \ ((struct ip *)(iph))->ip_tos &= 0xFC; \ ((struct ip *)(iph))->ip_tos |= IPH_ECN_ECT0; \ } /* * The format argument to pass to tcp_display(). * DISP_PORT_ONLY means that the returned string has only port info. * DISP_ADDR_AND_PORT means that the returned string also contains the * remote and local IP address. */ #define DISP_PORT_ONLY 1 #define DISP_ADDR_AND_PORT 2 /* * TCP reassembly macros. We hide starting and ending sequence numbers in * b_next and b_prev of messages on the reassembly queue. The messages are * chained using b_cont. These macros are used in tcp_reass() so we don't * have to see the ugly casts and assignments. * Note. use uintptr_t to suppress the gcc warning. */ #define TCP_REASS_SEQ(mp) ((uint32_t)(uintptr_t)((mp)->b_next)) #define TCP_REASS_SET_SEQ(mp, u) ((mp)->b_next = \ (mblk_t *)((uintptr_t)(u))) #define TCP_REASS_END(mp) ((uint32_t)(uintptr_t)((mp)->b_prev)) #define TCP_REASS_SET_END(mp, u) ((mp)->b_prev = \ (mblk_t *)((uintptr_t)(u))) #define TCP_TIMER_RESTART(tcp, intvl) \ (tcp)->tcp_rto_timeout = prom_gettime() + intvl; \ (tcp)->tcp_timer_running = B_TRUE; static int tcp_accept_comm(tcp_t *, tcp_t *, mblk_t *, uint_t); static mblk_t *tcp_ack_mp(tcp_t *); static in_port_t tcp_bindi(in_port_t, in_addr_t *, boolean_t, boolean_t); static uint16_t tcp_cksum(uint16_t *, uint32_t); static void tcp_clean_death(int, tcp_t *, int err); static tcp_t *tcp_conn_request(tcp_t *, mblk_t *mp, uint_t, uint_t); static char *tcp_display(tcp_t *, char *, char); static int tcp_drain_input(tcp_t *, int, int); static void tcp_drain_needed(int, tcp_t *); static boolean_t tcp_drop_q0(tcp_t *); static mblk_t *tcp_get_seg_mp(tcp_t *, uint32_t, int32_t *); static int tcp_header_len(struct inetgram *); static in_port_t tcp_report_ports(uint16_t *, enum Ports); static int tcp_input(int); static void tcp_iss_init(tcp_t *); static tcp_t *tcp_lookup_ipv4(struct ip *, tcpha_t *, int, int *); static tcp_t *tcp_lookup_listener_ipv4(in_addr_t, in_port_t, int *); static int tcp_conn_check(tcp_t *); static int tcp_close(int); static void tcp_close_detached(tcp_t *); static void tcp_eager_cleanup(tcp_t *, boolean_t, int); static void tcp_eager_unlink(tcp_t *); static void tcp_free(tcp_t *); static int tcp_header_init_ipv4(tcp_t *); static void tcp_mss_set(tcp_t *, uint32_t); static int tcp_parse_options(tcph_t *, tcp_opt_t *); static boolean_t tcp_paws_check(tcp_t *, tcph_t *, tcp_opt_t *); static void tcp_process_options(tcp_t *, tcph_t *); static int tcp_random(void); static void tcp_random_init(void); static mblk_t *tcp_reass(tcp_t *, mblk_t *, uint32_t); static void tcp_reass_elim_overlap(tcp_t *, mblk_t *); static void tcp_rcv_drain(int sock_id, tcp_t *); static void tcp_rcv_enqueue(tcp_t *, mblk_t *, uint_t); static void tcp_rput_data(tcp_t *, mblk_t *, int); static int tcp_rwnd_set(tcp_t *, uint32_t); static int32_t tcp_sack_rxmit(tcp_t *, int); static void tcp_set_cksum(mblk_t *); static void tcp_set_rto(tcp_t *, int32_t); static void tcp_ss_rexmit(tcp_t *, int); static int tcp_state_wait(int, tcp_t *, int); static void tcp_timer(tcp_t *, int); static void tcp_time_wait_append(tcp_t *); static void tcp_time_wait_collector(void); static void tcp_time_wait_processing(tcp_t *, mblk_t *, uint32_t, uint32_t, int, tcph_t *, int sock_id); static void tcp_time_wait_remove(tcp_t *); static in_port_t tcp_update_next_port(in_port_t); static int tcp_verify_cksum(mblk_t *); static void tcp_wput_data(tcp_t *, mblk_t *, int); static void tcp_xmit_ctl(char *, tcp_t *, mblk_t *, uint32_t, uint32_t, int, uint_t, int); static void tcp_xmit_early_reset(char *, int, mblk_t *, uint32_t, uint32_t, int, uint_t); static int tcp_xmit_end(tcp_t *, int); static void tcp_xmit_listeners_reset(int, mblk_t *, uint_t); static mblk_t *tcp_xmit_mp(tcp_t *, mblk_t *, int32_t, int32_t *, mblk_t **, uint32_t, boolean_t, uint32_t *, boolean_t); static int tcp_init_values(tcp_t *, struct inetboot_socket *); #if DEBUG > 1 #define TCP_DUMP_PACKET(str, mp) \ { \ int len = (mp)->b_wptr - (mp)->b_rptr; \ \ printf("%s: dump TCP(%d): \n", (str), len); \ hexdump((char *)(mp)->b_rptr, len); \ } #else #define TCP_DUMP_PACKET(str, mp) #endif #ifdef DEBUG #define DEBUG_1(str, arg) printf(str, (arg)) #define DEBUG_2(str, arg1, arg2) printf(str, (arg1), (arg2)) #define DEBUG_3(str, arg1, arg2, arg3) printf(str, (arg1), (arg2), (arg3)) #else #define DEBUG_1(str, arg) #define DEBUG_2(str, arg1, arg2) #define DEBUG_3(str, arg1, arg2, arg3) #endif /* Whether it is the first time TCP is used. */ static boolean_t tcp_initialized = B_FALSE; /* TCP time wait list. */ static tcp_t *tcp_time_wait_head; static tcp_t *tcp_time_wait_tail; static uint32_t tcp_cum_timewait; /* When the tcp_time_wait_collector is run. */ static uint32_t tcp_time_wait_runtime; #define TCP_RUN_TIME_WAIT_COLLECTOR() \ if (prom_gettime() > tcp_time_wait_runtime) \ tcp_time_wait_collector(); /* * Accept will return with an error if there is no connection coming in * after this (in ms). */ static int tcp_accept_timeout = 60000; /* * Initialize the TCP-specific parts of a socket. */ void tcp_socket_init(struct inetboot_socket *isp) { /* Do some initializations. */ if (!tcp_initialized) { tcp_random_init(); /* Extra head room for the MAC layer address. */ if ((tcp_wroff_xtra = mac_get_hdr_len()) & 0x3) { tcp_wroff_xtra = (tcp_wroff_xtra & ~0x3) + 0x4; } /* Schedule the first time wait cleanup time */ tcp_time_wait_runtime = prom_gettime() + tcp_time_wait_interval; tcp_initialized = B_TRUE; } TCP_RUN_TIME_WAIT_COLLECTOR(); isp->proto = IPPROTO_TCP; isp->input[TRANSPORT_LVL] = tcp_input; /* Socket layer should call tcp_send() directly. */ isp->output[TRANSPORT_LVL] = NULL; isp->close[TRANSPORT_LVL] = tcp_close; isp->headerlen[TRANSPORT_LVL] = tcp_header_len; isp->ports = tcp_report_ports; if ((isp->pcb = bkmem_alloc(sizeof (tcp_t))) == NULL) { errno = ENOBUFS; return; } if ((errno = tcp_init_values((tcp_t *)isp->pcb, isp)) != 0) { bkmem_free(isp->pcb, sizeof (tcp_t)); return; } /* * This is set last because this field is used to determine if * a socket is in use or not. */ isp->type = INETBOOT_STREAM; } /* * Return the size of a TCP header including TCP option. */ static int tcp_header_len(struct inetgram *igm) { mblk_t *pkt; int ipvers; /* Just returns the standard TCP header without option */ if (igm == NULL) return (sizeof (tcph_t)); if ((pkt = igm->igm_mp) == NULL) return (0); ipvers = ((struct ip *)pkt->b_rptr)->ip_v; if (ipvers == IPV4_VERSION) { return (TCP_HDR_LENGTH((tcph_t *)(pkt + IPH_HDR_LENGTH(pkt)))); } else { dprintf("tcp_header_len: non-IPv4 packet.\n"); return (0); } } /* * Return the requested port number in network order. */ static in_port_t tcp_report_ports(uint16_t *tcphp, enum Ports request) { if (request == SOURCE) return (*(uint16_t *)(((tcph_t *)tcphp)->th_lport)); return (*(uint16_t *)(((tcph_t *)tcphp)->th_fport)); } /* * Because inetboot is not interrupt driven, TCP can only poll. This * means that there can be packets stuck in the NIC buffer waiting to * be processed. Thus we need to drain them before, for example, sending * anything because an ACK may actually be stuck there. * * The timeout arguments determine how long we should wait for draining. */ static int tcp_drain_input(tcp_t *tcp, int sock_id, int timeout) { struct inetgram *in_gram; struct inetgram *old_in_gram; int old_timeout; mblk_t *mp; int i; dprintf("tcp_drain_input(%d): %s\n", sock_id, tcp_display(tcp, NULL, DISP_ADDR_AND_PORT)); /* * Since the driver uses the in_timeout value in the socket * structure to determine the timeout value, we need to save * the original one so that we can restore that after draining. */ old_timeout = sockets[sock_id].in_timeout; sockets[sock_id].in_timeout = timeout; /* * We do this because the input queue may have some user * data already. */ old_in_gram = sockets[sock_id].inq; sockets[sock_id].inq = NULL; /* Go out and check the wire */ for (i = MEDIA_LVL; i < TRANSPORT_LVL; i++) { if (sockets[sock_id].input[i] != NULL) { if (sockets[sock_id].input[i](sock_id) < 0) { sockets[sock_id].in_timeout = old_timeout; if (sockets[sock_id].inq != NULL) nuke_grams(&sockets[sock_id].inq); sockets[sock_id].inq = old_in_gram; return (-1); } } } #if DEBUG printf("tcp_drain_input: done with checking packets\n"); #endif while ((in_gram = sockets[sock_id].inq) != NULL) { /* Remove unknown inetgrams from the head of inq. */ if (in_gram->igm_level != TRANSPORT_LVL) { #if DEBUG printf("tcp_drain_input: unexpected packet " "level %d frame found\n", in_gram->igm_level); #endif del_gram(&sockets[sock_id].inq, in_gram, B_TRUE); continue; } mp = in_gram->igm_mp; del_gram(&sockets[sock_id].inq, in_gram, B_FALSE); bkmem_free((caddr_t)in_gram, sizeof (struct inetgram)); tcp_rput_data(tcp, mp, sock_id); sockets[sock_id].in_timeout = old_timeout; /* * The other side may have closed this connection or * RST us. But we need to continue to process other * packets in the socket's queue because they may be * belong to another TCP connections. */ if (sockets[sock_id].pcb == NULL) tcp = NULL; } if (tcp == NULL || sockets[sock_id].pcb == NULL) { if (sockets[sock_id].so_error != 0) return (-1); else return (0); } #if DEBUG printf("tcp_drain_input: done with processing packets\n"); #endif sockets[sock_id].in_timeout = old_timeout; sockets[sock_id].inq = old_in_gram; /* * Data may have been received so indicate it is available */ tcp_drain_needed(sock_id, tcp); return (0); } /* * The receive entry point for upper layer to call to get data. Note * that this follows the current architecture that lower layer receive * routines have been called already. Thus if the inq of socket is * not NULL, the packets must be for us. */ static int tcp_input(int sock_id) { struct inetgram *in_gram; mblk_t *mp; tcp_t *tcp; TCP_RUN_TIME_WAIT_COLLECTOR(); if ((tcp = sockets[sock_id].pcb) == NULL) return (-1); while ((in_gram = sockets[sock_id].inq) != NULL) { /* Remove unknown inetgrams from the head of inq. */ if (in_gram->igm_level != TRANSPORT_LVL) { #ifdef DEBUG printf("tcp_input: unexpected packet " "level %d frame found\n", in_gram->igm_level); #endif del_gram(&sockets[sock_id].inq, in_gram, B_TRUE); continue; } mp = in_gram->igm_mp; del_gram(&sockets[sock_id].inq, in_gram, B_FALSE); bkmem_free((caddr_t)in_gram, sizeof (struct inetgram)); tcp_rput_data(tcp, mp, sock_id); /* The TCP may be gone because it gets a RST. */ if (sockets[sock_id].pcb == NULL) return (-1); } /* Flush the receive list. */ if (tcp->tcp_rcv_list != NULL) { tcp_rcv_drain(sock_id, tcp); } else { /* The other side has closed the connection, report this up. */ if (tcp->tcp_state == TCPS_CLOSE_WAIT) { sockets[sock_id].so_state |= SS_CANTRCVMORE; return (0); } } return (0); } /* * The send entry point for upper layer to call to send data. In order * to minimize changes to the core TCP code, we need to put the * data into mblks. */ int tcp_send(int sock_id, tcp_t *tcp, const void *msg, int len) { mblk_t *mp; mblk_t *head = NULL; mblk_t *tail; int mss = tcp->tcp_mss; int cnt = 0; int win_size; char *buf = (char *)msg; TCP_RUN_TIME_WAIT_COLLECTOR(); /* We don't want to append 0 size mblk. */ if (len == 0) return (0); while (len > 0) { if (len < mss) { mss = len; } /* * If we cannot allocate more buffer, stop here and * the number of bytes buffered will be returned. * * Note that we follow the core TCP optimization that * each mblk contains only MSS bytes data. */ if ((mp = allocb(mss + tcp->tcp_ip_hdr_len + TCP_MAX_HDR_LENGTH + tcp_wroff_xtra, 0)) == NULL) { break; } mp->b_rptr += tcp->tcp_hdr_len + tcp_wroff_xtra; bcopy(buf, mp->b_rptr, mss); mp->b_wptr = mp->b_rptr + mss; buf += mss; cnt += mss; len -= mss; if (head == NULL) { head = mp; tail = mp; } else { tail->b_cont = mp; tail = mp; } } /* * Since inetboot is not interrupt driven, there may be * some ACKs in the MAC's buffer. Drain them first, * otherwise, we may not be able to send. * * We expect an ACK in two cases: * * 1) We have un-ACK'ed data. * * 2) All ACK's have been received and the sender's window has been * closed. We need an ACK back to open the window so that we can * send. In this case, call tcp_drain_input() if the window size is * less than 2 * MSS. */ /* window size = MIN(swnd, cwnd) - unacked bytes */ win_size = (tcp->tcp_swnd > tcp->tcp_cwnd) ? tcp->tcp_cwnd : tcp->tcp_swnd; win_size -= tcp->tcp_snxt; win_size += tcp->tcp_suna; if (win_size < (2 * tcp->tcp_mss)) if (tcp_drain_input(tcp, sock_id, 5) < 0) return (-1); tcp_wput_data(tcp, head, sock_id); return (cnt); } /* Free up all TCP related stuff */ static void tcp_free(tcp_t *tcp) { if (tcp->tcp_iphc != NULL) { bkmem_free((caddr_t)tcp->tcp_iphc, tcp->tcp_iphc_len); tcp->tcp_iphc = NULL; } if (tcp->tcp_xmit_head != NULL) { freemsg(tcp->tcp_xmit_head); tcp->tcp_xmit_head = NULL; } if (tcp->tcp_rcv_list != NULL) { freemsg(tcp->tcp_rcv_list); tcp->tcp_rcv_list = NULL; } if (tcp->tcp_reass_head != NULL) { freemsg(tcp->tcp_reass_head); tcp->tcp_reass_head = NULL; } if (tcp->tcp_sack_info != NULL) { bkmem_free((caddr_t)tcp->tcp_sack_info, sizeof (tcp_sack_info_t)); tcp->tcp_sack_info = NULL; } } static void tcp_close_detached(tcp_t *tcp) { if (tcp->tcp_listener != NULL) tcp_eager_unlink(tcp); tcp_free(tcp); bkmem_free((caddr_t)tcp, sizeof (tcp_t)); } /* * If we are an eager connection hanging off a listener that hasn't * formally accepted the connection yet, get off his list and blow off * any data that we have accumulated. */ static void tcp_eager_unlink(tcp_t *tcp) { tcp_t *listener = tcp->tcp_listener; assert(listener != NULL); if (tcp->tcp_eager_next_q0 != NULL) { assert(tcp->tcp_eager_prev_q0 != NULL); /* Remove the eager tcp from q0 */ tcp->tcp_eager_next_q0->tcp_eager_prev_q0 = tcp->tcp_eager_prev_q0; tcp->tcp_eager_prev_q0->tcp_eager_next_q0 = tcp->tcp_eager_next_q0; listener->tcp_conn_req_cnt_q0--; } else { tcp_t **tcpp = &listener->tcp_eager_next_q; tcp_t *prev = NULL; for (; tcpp[0]; tcpp = &tcpp[0]->tcp_eager_next_q) { if (tcpp[0] == tcp) { if (listener->tcp_eager_last_q == tcp) { /* * If we are unlinking the last * element on the list, adjust * tail pointer. Set tail pointer * to nil when list is empty. */ assert(tcp->tcp_eager_next_q == NULL); if (listener->tcp_eager_last_q == listener->tcp_eager_next_q) { listener->tcp_eager_last_q = NULL; } else { /* * We won't get here if there * is only one eager in the * list. */ assert(prev != NULL); listener->tcp_eager_last_q = prev; } } tcpp[0] = tcp->tcp_eager_next_q; tcp->tcp_eager_next_q = NULL; tcp->tcp_eager_last_q = NULL; listener->tcp_conn_req_cnt_q--; break; } prev = tcpp[0]; } } tcp->tcp_listener = NULL; } /* * Reset any eager connection hanging off this listener * and then reclaim it's resources. */ static void tcp_eager_cleanup(tcp_t *listener, boolean_t q0_only, int sock_id) { tcp_t *eager; if (!q0_only) { /* First cleanup q */ while ((eager = listener->tcp_eager_next_q) != NULL) { assert(listener->tcp_eager_last_q != NULL); tcp_xmit_ctl("tcp_eager_cleanup, can't wait", eager, NULL, eager->tcp_snxt, 0, TH_RST, 0, sock_id); tcp_close_detached(eager); } assert(listener->tcp_eager_last_q == NULL); } /* Then cleanup q0 */ while ((eager = listener->tcp_eager_next_q0) != listener) { tcp_xmit_ctl("tcp_eager_cleanup, can't wait", eager, NULL, eager->tcp_snxt, 0, TH_RST, 0, sock_id); tcp_close_detached(eager); } } /* * To handle the shutdown request. Called from shutdown() */ int tcp_shutdown(int sock_id) { tcp_t *tcp; DEBUG_1("tcp_shutdown: sock_id %x\n", sock_id); if ((tcp = sockets[sock_id].pcb) == NULL) { return (-1); } /* * Since inetboot is not interrupt driven, there may be * some ACKs in the MAC's buffer. Drain them first, * otherwise, we may not be able to send. */ if (tcp_drain_input(tcp, sock_id, 5) < 0) { /* * If we return now without freeing TCP, there will be * a memory leak. */ if (sockets[sock_id].pcb != NULL) tcp_clean_death(sock_id, tcp, 0); return (-1); } DEBUG_1("tcp_shutdown: tcp_state %x\n", tcp->tcp_state); switch (tcp->tcp_state) { case TCPS_SYN_RCVD: /* * Shutdown during the connect 3-way handshake */ case TCPS_ESTABLISHED: /* * Transmit the FIN * wait for the FIN to be ACKed, * then remain in FIN_WAIT_2 */ dprintf("tcp_shutdown: sending fin\n"); if (tcp_xmit_end(tcp, sock_id) == 0 && tcp_state_wait(sock_id, tcp, TCPS_FIN_WAIT_2) < 0) { /* During the wait, TCP may be gone... */ if (sockets[sock_id].pcb == NULL) return (-1); } dprintf("tcp_shutdown: done\n"); break; default: break; } return (0); } /* To handle closing of the socket */ static int tcp_close(int sock_id) { char *msg; tcp_t *tcp; int error = 0; if ((tcp = sockets[sock_id].pcb) == NULL) { return (-1); } TCP_RUN_TIME_WAIT_COLLECTOR(); /* * Since inetboot is not interrupt driven, there may be * some ACKs in the MAC's buffer. Drain them first, * otherwise, we may not be able to send. */ if (tcp_drain_input(tcp, sock_id, 5) < 0) { /* * If we return now without freeing TCP, there will be * a memory leak. */ if (sockets[sock_id].pcb != NULL) tcp_clean_death(sock_id, tcp, 0); return (-1); } if (tcp->tcp_conn_req_cnt_q0 != 0 || tcp->tcp_conn_req_cnt_q != 0) { /* Cleanup for listener */ tcp_eager_cleanup(tcp, 0, sock_id); } msg = NULL; switch (tcp->tcp_state) { case TCPS_CLOSED: case TCPS_IDLE: case TCPS_BOUND: case TCPS_LISTEN: break; case TCPS_SYN_SENT: msg = "tcp_close, during connect"; break; case TCPS_SYN_RCVD: /* * Close during the connect 3-way handshake * but here there may or may not be pending data * already on queue. Process almost same as in * the ESTABLISHED state. */ /* FALLTHRU */ default: /* * If SO_LINGER has set a zero linger time, abort the * connection with a reset. */ if (tcp->tcp_linger && tcp->tcp_lingertime == 0) { msg = "tcp_close, zero lingertime"; break; } /* * Abort connection if there is unread data queued. */ if (tcp->tcp_rcv_list != NULL || tcp->tcp_reass_head != NULL) { msg = "tcp_close, unread data"; break; } if (tcp->tcp_state <= TCPS_LISTEN) break; /* * Transmit the FIN before detaching the tcp_t. * After tcp_detach returns this queue/perimeter * no longer owns the tcp_t thus others can modify it. * The TCP could be closed in tcp_state_wait called by * tcp_wput_data called by tcp_xmit_end. */ (void) tcp_xmit_end(tcp, sock_id); if (sockets[sock_id].pcb == NULL) return (0); /* * If lingering on close then wait until the fin is acked, * the SO_LINGER time passes, or a reset is sent/received. */ if (tcp->tcp_linger && tcp->tcp_lingertime > 0 && !(tcp->tcp_fin_acked) && tcp->tcp_state >= TCPS_ESTABLISHED) { uint32_t stoptime; /* in ms */ tcp->tcp_client_errno = 0; stoptime = prom_gettime() + (tcp->tcp_lingertime * 1000); while (!(tcp->tcp_fin_acked) && tcp->tcp_state >= TCPS_ESTABLISHED && tcp->tcp_client_errno == 0 && ((int32_t)(stoptime - prom_gettime()) > 0)) { if (tcp_drain_input(tcp, sock_id, 5) < 0) { if (sockets[sock_id].pcb != NULL) { tcp_clean_death(sock_id, tcp, 0); } return (-1); } } tcp->tcp_client_errno = 0; } if (tcp_state_wait(sock_id, tcp, TCPS_TIME_WAIT) < 0) { /* During the wait, TCP may be gone... */ if (sockets[sock_id].pcb == NULL) return (0); msg = "tcp_close, couldn't detach"; } else { return (0); } break; } /* Something went wrong... Send a RST and report the error */ if (msg != NULL) { if (tcp->tcp_state == TCPS_ESTABLISHED || tcp->tcp_state == TCPS_CLOSE_WAIT) BUMP_MIB(tcp_mib.tcpEstabResets); if (tcp->tcp_state == TCPS_SYN_SENT || tcp->tcp_state == TCPS_SYN_RCVD) BUMP_MIB(tcp_mib.tcpAttemptFails); tcp_xmit_ctl(msg, tcp, NULL, tcp->tcp_snxt, 0, TH_RST, 0, sock_id); } tcp_free(tcp); bkmem_free((caddr_t)tcp, sizeof (tcp_t)); sockets[sock_id].pcb = NULL; return (error); } /* To make an endpoint a listener. */ int tcp_listen(int sock_id, int backlog) { tcp_t *tcp; if ((tcp = (tcp_t *)(sockets[sock_id].pcb)) == NULL) { errno = EINVAL; return (-1); } /* We allow calling listen() multiple times to change the backlog. */ if (tcp->tcp_state > TCPS_LISTEN || tcp->tcp_state < TCPS_BOUND) { errno = EOPNOTSUPP; return (-1); } /* The following initialization should only be done once. */ if (tcp->tcp_state != TCPS_LISTEN) { tcp->tcp_eager_next_q0 = tcp->tcp_eager_prev_q0 = tcp; tcp->tcp_eager_next_q = NULL; tcp->tcp_state = TCPS_LISTEN; tcp->tcp_second_ctimer_threshold = tcp_ip_abort_linterval; } if ((tcp->tcp_conn_req_max = backlog) > tcp_conn_req_max_q) { tcp->tcp_conn_req_max = tcp_conn_req_max_q; } if (tcp->tcp_conn_req_max < tcp_conn_req_min) { tcp->tcp_conn_req_max = tcp_conn_req_min; } return (0); } /* To accept connections. */ int tcp_accept(int sock_id, struct sockaddr *addr, socklen_t *addr_len) { tcp_t *listener; tcp_t *eager; int sd, new_sock_id; struct sockaddr_in *new_addr = (struct sockaddr_in *)addr; int timeout; /* Sanity check. */ if ((listener = (tcp_t *)(sockets[sock_id].pcb)) == NULL || new_addr == NULL || addr_len == NULL || *addr_len < sizeof (struct sockaddr_in) || listener->tcp_state != TCPS_LISTEN) { errno = EINVAL; return (-1); } if (sockets[sock_id].in_timeout > tcp_accept_timeout) timeout = prom_gettime() + sockets[sock_id].in_timeout; else timeout = prom_gettime() + tcp_accept_timeout; while (listener->tcp_eager_next_q == NULL && timeout > prom_gettime()) { #if DEBUG printf("tcp_accept: Waiting in tcp_accept()\n"); #endif if (tcp_drain_input(listener, sock_id, 5) < 0) { return (-1); } } /* If there is an eager, don't timeout... */ if (timeout <= prom_gettime() && listener->tcp_eager_next_q == NULL) { #if DEBUG printf("tcp_accept: timeout\n"); #endif errno = ETIMEDOUT; return (-1); } #if DEBUG printf("tcp_accept: got a connection\n"); #endif /* Now create the socket for this new TCP. */ if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { return (-1); } if ((new_sock_id = so_check_fd(sd, &errno)) == -1) /* This should not happen! */ prom_panic("so_check_fd() fails in tcp_accept()"); /* Free the TCP PCB in the original socket. */ bkmem_free((caddr_t)(sockets[new_sock_id].pcb), sizeof (tcp_t)); /* Dequeue the eager and attach it to the socket. */ eager = listener->tcp_eager_next_q; listener->tcp_eager_next_q = eager->tcp_eager_next_q; if (listener->tcp_eager_last_q == eager) listener->tcp_eager_last_q = NULL; eager->tcp_eager_next_q = NULL; sockets[new_sock_id].pcb = eager; listener->tcp_conn_req_cnt_q--; /* Copy in the address info. */ bcopy(&eager->tcp_remote, &new_addr->sin_addr.s_addr, sizeof (in_addr_t)); bcopy(&eager->tcp_fport, &new_addr->sin_port, sizeof (in_port_t)); new_addr->sin_family = AF_INET; #ifdef DEBUG printf("tcp_accept(), new sock_id: %d\n", sd); #endif return (sd); } /* Update the next anonymous port to use. */ static in_port_t tcp_update_next_port(in_port_t port) { /* Don't allow the port to fall out of the anonymous port range. */ if (port < tcp_smallest_anon_port || port > tcp_largest_anon_port) port = (in_port_t)tcp_smallest_anon_port; if (port < tcp_smallest_nonpriv_port) port = (in_port_t)tcp_smallest_nonpriv_port; return (port); } /* To check whether a bind to a port is allowed. */ static in_port_t tcp_bindi(in_port_t port, in_addr_t *addr, boolean_t reuseaddr, boolean_t bind_to_req_port_only) { int i, count; tcp_t *tcp; count = tcp_largest_anon_port - tcp_smallest_anon_port; try_again: for (i = 0; i < MAXSOCKET; i++) { if (sockets[i].type != INETBOOT_STREAM || ((tcp = (tcp_t *)sockets[i].pcb) == NULL) || ntohs(tcp->tcp_lport) != port) { continue; } /* * Both TCPs have the same port. If SO_REUSEDADDR is * set and the bound TCP has a state greater than * TCPS_LISTEN, it is fine. */ if (reuseaddr && tcp->tcp_state > TCPS_LISTEN) { continue; } if (tcp->tcp_bound_source != INADDR_ANY && *addr != INADDR_ANY && tcp->tcp_bound_source != *addr) { continue; } if (bind_to_req_port_only) { return (0); } if (--count > 0) { port = tcp_update_next_port(++port); goto try_again; } else { return (0); } } return (port); } /* To handle the bind request. */ int tcp_bind(int sock_id) { tcp_t *tcp; in_port_t requested_port, allocated_port; boolean_t bind_to_req_port_only; boolean_t reuseaddr; if ((tcp = (tcp_t *)sockets[sock_id].pcb) == NULL) { errno = EINVAL; return (-1); } if (tcp->tcp_state >= TCPS_BOUND) { /* We don't allow multiple bind(). */ errno = EPROTO; return (-1); } requested_port = ntohs(sockets[sock_id].bind.sin_port); /* The bound source can be INADDR_ANY. */ tcp->tcp_bound_source = sockets[sock_id].bind.sin_addr.s_addr; tcp->tcp_ipha->ip_src.s_addr = tcp->tcp_bound_source; /* Verify the port is available. */ if (requested_port == 0) bind_to_req_port_only = B_FALSE; else /* T_BIND_REQ and requested_port != 0 */ bind_to_req_port_only = B_TRUE; if (requested_port == 0) { requested_port = tcp_update_next_port(++tcp_next_port_to_try); } reuseaddr = sockets[sock_id].so_opt & SO_REUSEADDR; allocated_port = tcp_bindi(requested_port, &(tcp->tcp_bound_source), reuseaddr, bind_to_req_port_only); if (allocated_port == 0) { errno = EADDRINUSE; return (-1); } tcp->tcp_lport = htons(allocated_port); *(uint16_t *)tcp->tcp_tcph->th_lport = tcp->tcp_lport; sockets[sock_id].bind.sin_port = tcp->tcp_lport; tcp->tcp_state = TCPS_BOUND; return (0); } /* * Check for duplicate TCP connections. */ static int tcp_conn_check(tcp_t *tcp) { int i; tcp_t *tmp_tcp; for (i = 0; i < MAXSOCKET; i++) { if (sockets[i].type != INETBOOT_STREAM) continue; /* Socket may not be closed but the TCP can be gone. */ if ((tmp_tcp = (tcp_t *)sockets[i].pcb) == NULL) continue; /* We only care about TCP in states later than SYN_SENT. */ if (tmp_tcp->tcp_state < TCPS_SYN_SENT) continue; if (tmp_tcp->tcp_lport != tcp->tcp_lport || tmp_tcp->tcp_fport != tcp->tcp_fport || tmp_tcp->tcp_bound_source != tcp->tcp_bound_source || tmp_tcp->tcp_remote != tcp->tcp_remote) { continue; } else { return (-1); } } return (0); } /* To handle a connect request. */ int tcp_connect(int sock_id) { tcp_t *tcp; in_addr_t dstaddr; in_port_t dstport; tcph_t *tcph; int mss; mblk_t *syn_mp; if ((tcp = (tcp_t *)(sockets[sock_id].pcb)) == NULL) { errno = EINVAL; return (-1); } TCP_RUN_TIME_WAIT_COLLECTOR(); dstaddr = sockets[sock_id].remote.sin_addr.s_addr; dstport = sockets[sock_id].remote.sin_port; /* * Check for attempt to connect to INADDR_ANY or non-unicast addrress. * We don't have enough info to check for broadcast addr, except * for the all 1 broadcast. */ if (dstaddr == INADDR_ANY || IN_CLASSD(ntohl(dstaddr)) || dstaddr == INADDR_BROADCAST) { /* * SunOS 4.x and 4.3 BSD allow an application * to connect a TCP socket to INADDR_ANY. * When they do this, the kernel picks the * address of one interface and uses it * instead. The kernel usually ends up * picking the address of the loopback * interface. This is an undocumented feature. * However, we provide the same thing here * in order to have source and binary * compatibility with SunOS 4.x. * Update the T_CONN_REQ (sin/sin6) since it is used to * generate the T_CONN_CON. * * Fail this for inetboot TCP. */ errno = EINVAL; return (-1); } /* It is not bound to any address yet... */ if (tcp->tcp_bound_source == INADDR_ANY) { ipv4_getipaddr(&(sockets[sock_id].bind.sin_addr)); /* We don't have an address! */ if (ntohl(sockets[sock_id].bind.sin_addr.s_addr) == INADDR_ANY) { errno = EPROTO; return (-1); } tcp->tcp_bound_source = sockets[sock_id].bind.sin_addr.s_addr; tcp->tcp_ipha->ip_src.s_addr = tcp->tcp_bound_source; } /* * Don't let an endpoint connect to itself. */ if (dstaddr == tcp->tcp_ipha->ip_src.s_addr && dstport == tcp->tcp_lport) { errno = EINVAL; return (-1); } tcp->tcp_ipha->ip_dst.s_addr = dstaddr; tcp->tcp_remote = dstaddr; tcph = tcp->tcp_tcph; *(uint16_t *)tcph->th_fport = dstport; tcp->tcp_fport = dstport; /* * Don't allow this connection to completely duplicate * an existing connection. */ if (tcp_conn_check(tcp) < 0) { errno = EADDRINUSE; return (-1); } /* * Just make sure our rwnd is at * least tcp_recv_hiwat_mss * MSS * large, and round up to the nearest * MSS. * * We do the round up here because * we need to get the interface * MTU first before we can do the * round up. */ mss = tcp->tcp_mss - tcp->tcp_hdr_len; tcp->tcp_rwnd = MAX(MSS_ROUNDUP(tcp->tcp_rwnd, mss), tcp_recv_hiwat_minmss * mss); tcp->tcp_rwnd_max = tcp->tcp_rwnd; SET_WS_VALUE(tcp); U32_TO_ABE16((tcp->tcp_rwnd >> tcp->tcp_rcv_ws), tcp->tcp_tcph->th_win); if (tcp->tcp_rcv_ws > 0 || tcp_wscale_always) tcp->tcp_snd_ws_ok = B_TRUE; /* * Set tcp_snd_ts_ok to true * so that tcp_xmit_mp will * include the timestamp * option in the SYN segment. */ if (tcp_tstamp_always || (tcp->tcp_rcv_ws && tcp_tstamp_if_wscale)) { tcp->tcp_snd_ts_ok = B_TRUE; } if (tcp_sack_permitted == 2 || tcp->tcp_snd_sack_ok) { assert(tcp->tcp_sack_info == NULL); if ((tcp->tcp_sack_info = (tcp_sack_info_t *)bkmem_zalloc( sizeof (tcp_sack_info_t))) == NULL) { tcp->tcp_snd_sack_ok = B_FALSE; } else { tcp->tcp_snd_sack_ok = B_TRUE; } } /* * Should we use ECN? Note that the current * default value (SunOS 5.9) of tcp_ecn_permitted * is 2. The reason for doing this is that there * are equipments out there that will drop ECN * enabled IP packets. Setting it to 1 avoids * compatibility problems. */ if (tcp_ecn_permitted == 2) tcp->tcp_ecn_ok = B_TRUE; tcp_iss_init(tcp); TCP_TIMER_RESTART(tcp, tcp->tcp_rto); tcp->tcp_active_open = B_TRUE; tcp->tcp_state = TCPS_SYN_SENT; syn_mp = tcp_xmit_mp(tcp, NULL, 0, NULL, NULL, tcp->tcp_iss, B_FALSE, NULL, B_FALSE); if (syn_mp != NULL) { int ret; /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_connect", syn_mp); /* Send out the SYN packet. */ ret = ipv4_tcp_output(sock_id, syn_mp); freeb(syn_mp); if (ret < 0) { return (-1); } /* tcp_state_wait() will finish the 3 way handshake. */ return (tcp_state_wait(sock_id, tcp, TCPS_ESTABLISHED)); } else { errno = ENOBUFS; return (-1); } } /* * Common accept code. Called by tcp_conn_request. * cr_pkt is the SYN packet. */ static int tcp_accept_comm(tcp_t *listener, tcp_t *acceptor, mblk_t *cr_pkt, uint_t ip_hdr_len) { tcph_t *tcph; #ifdef DEBUG printf("tcp_accept_comm #######################\n"); #endif /* * When we get here, we know that the acceptor header template * has already been initialized. * However, it may not match the listener if the listener * includes options... * It may also not match the listener if the listener is v6 and * and the acceptor is v4 */ acceptor->tcp_lport = listener->tcp_lport; if (listener->tcp_ipversion == acceptor->tcp_ipversion) { if (acceptor->tcp_iphc_len != listener->tcp_iphc_len) { /* * Listener had options of some sort; acceptor inherits. * Free up the acceptor template and allocate one * of the right size. */ bkmem_free(acceptor->tcp_iphc, acceptor->tcp_iphc_len); acceptor->tcp_iphc = bkmem_zalloc( listener->tcp_iphc_len); if (acceptor->tcp_iphc == NULL) { acceptor->tcp_iphc_len = 0; return (ENOMEM); } acceptor->tcp_iphc_len = listener->tcp_iphc_len; } acceptor->tcp_hdr_len = listener->tcp_hdr_len; acceptor->tcp_ip_hdr_len = listener->tcp_ip_hdr_len; acceptor->tcp_tcp_hdr_len = listener->tcp_tcp_hdr_len; /* * Copy the IP+TCP header template from listener to acceptor */ bcopy(listener->tcp_iphc, acceptor->tcp_iphc, listener->tcp_hdr_len); acceptor->tcp_ipha = (struct ip *)acceptor->tcp_iphc; acceptor->tcp_tcph = (tcph_t *)(acceptor->tcp_iphc + acceptor->tcp_ip_hdr_len); } else { prom_panic("tcp_accept_comm: version not equal"); } /* Copy our new dest and fport from the connection request packet */ if (acceptor->tcp_ipversion == IPV4_VERSION) { struct ip *ipha; ipha = (struct ip *)cr_pkt->b_rptr; acceptor->tcp_ipha->ip_dst = ipha->ip_src; acceptor->tcp_remote = ipha->ip_src.s_addr; acceptor->tcp_ipha->ip_src = ipha->ip_dst; acceptor->tcp_bound_source = ipha->ip_dst.s_addr; tcph = (tcph_t *)&cr_pkt->b_rptr[ip_hdr_len]; } else { prom_panic("tcp_accept_comm: not IPv4"); } bcopy(tcph->th_lport, acceptor->tcp_tcph->th_fport, sizeof (in_port_t)); bcopy(acceptor->tcp_tcph->th_fport, &acceptor->tcp_fport, sizeof (in_port_t)); /* * For an all-port proxy listener, the local port is determined by * the port number field in the SYN packet. */ if (listener->tcp_lport == 0) { acceptor->tcp_lport = *(in_port_t *)tcph->th_fport; bcopy(tcph->th_fport, acceptor->tcp_tcph->th_lport, sizeof (in_port_t)); } /* Inherit various TCP parameters from the listener */ acceptor->tcp_naglim = listener->tcp_naglim; acceptor->tcp_first_timer_threshold = listener->tcp_first_timer_threshold; acceptor->tcp_second_timer_threshold = listener->tcp_second_timer_threshold; acceptor->tcp_first_ctimer_threshold = listener->tcp_first_ctimer_threshold; acceptor->tcp_second_ctimer_threshold = listener->tcp_second_ctimer_threshold; acceptor->tcp_xmit_hiwater = listener->tcp_xmit_hiwater; acceptor->tcp_state = TCPS_LISTEN; tcp_iss_init(acceptor); /* Process all TCP options. */ tcp_process_options(acceptor, tcph); /* Is the other end ECN capable? */ if (tcp_ecn_permitted >= 1 && (tcph->th_flags[0] & (TH_ECE|TH_CWR)) == (TH_ECE|TH_CWR)) { acceptor->tcp_ecn_ok = B_TRUE; } /* * listener->tcp_rq->q_hiwat should be the default window size or a * window size changed via SO_RCVBUF option. First round up the * acceptor's tcp_rwnd to the nearest MSS. Then find out the window * scale option value if needed. Call tcp_rwnd_set() to finish the * setting. * * Note if there is a rpipe metric associated with the remote host, * we should not inherit receive window size from listener. */ acceptor->tcp_rwnd = MSS_ROUNDUP( (acceptor->tcp_rwnd == 0 ? listener->tcp_rwnd_max : acceptor->tcp_rwnd), acceptor->tcp_mss); if (acceptor->tcp_snd_ws_ok) SET_WS_VALUE(acceptor); /* * Note that this is the only place tcp_rwnd_set() is called for * accepting a connection. We need to call it here instead of * after the 3-way handshake because we need to tell the other * side our rwnd in the SYN-ACK segment. */ (void) tcp_rwnd_set(acceptor, acceptor->tcp_rwnd); return (0); } /* * Defense for the SYN attack - * 1. When q0 is full, drop from the tail (tcp_eager_prev_q0) the oldest * one that doesn't have the dontdrop bit set. * 2. Don't drop a SYN request before its first timeout. This gives every * request at least til the first timeout to complete its 3-way handshake. * 3. The current threshold is - # of timeout > q0len/4 => SYN alert on * # of timeout drops back to <= q0len/32 => SYN alert off */ static boolean_t tcp_drop_q0(tcp_t *tcp) { tcp_t *eager; assert(tcp->tcp_eager_next_q0 != tcp->tcp_eager_prev_q0); /* * New one is added after next_q0 so prev_q0 points to the oldest * Also do not drop any established connections that are deferred on * q0 due to q being full */ eager = tcp->tcp_eager_prev_q0; while (eager->tcp_dontdrop || eager->tcp_conn_def_q0) { /* XXX should move the eager to the head */ eager = eager->tcp_eager_prev_q0; if (eager == tcp) { eager = tcp->tcp_eager_prev_q0; break; } } dprintf("tcp_drop_q0: listen half-open queue (max=%d) overflow" " (%d pending) on %s, drop one", tcp_conn_req_max_q0, tcp->tcp_conn_req_cnt_q0, tcp_display(tcp, NULL, DISP_PORT_ONLY)); BUMP_MIB(tcp_mib.tcpHalfOpenDrop); bkmem_free((caddr_t)eager, sizeof (tcp_t)); return (B_TRUE); } /* ARGSUSED */ static tcp_t * tcp_conn_request(tcp_t *tcp, mblk_t *mp, uint_t sock_id, uint_t ip_hdr_len) { tcp_t *eager; struct ip *ipha; int err; #ifdef DEBUG printf("tcp_conn_request ###################\n"); #endif if (tcp->tcp_conn_req_cnt_q >= tcp->tcp_conn_req_max) { BUMP_MIB(tcp_mib.tcpListenDrop); dprintf("tcp_conn_request: listen backlog (max=%d) " "overflow (%d pending) on %s", tcp->tcp_conn_req_max, tcp->tcp_conn_req_cnt_q, tcp_display(tcp, NULL, DISP_PORT_ONLY)); return (NULL); } assert(OK_32PTR(mp->b_rptr)); if (tcp->tcp_conn_req_cnt_q0 >= tcp->tcp_conn_req_max + tcp_conn_req_max_q0) { /* * Q0 is full. Drop a pending half-open req from the queue * to make room for the new SYN req. Also mark the time we * drop a SYN. */ tcp->tcp_last_rcv_lbolt = prom_gettime(); if (!tcp_drop_q0(tcp)) { freemsg(mp); BUMP_MIB(tcp_mib.tcpListenDropQ0); dprintf("tcp_conn_request: listen half-open queue " "(max=%d) full (%d pending) on %s", tcp_conn_req_max_q0, tcp->tcp_conn_req_cnt_q0, tcp_display(tcp, NULL, DISP_PORT_ONLY)); return (NULL); } } ipha = (struct ip *)mp->b_rptr; if (IN_CLASSD(ntohl(ipha->ip_src.s_addr)) || ipha->ip_src.s_addr == INADDR_BROADCAST || ipha->ip_src.s_addr == INADDR_ANY || ipha->ip_dst.s_addr == INADDR_BROADCAST) { freemsg(mp); return (NULL); } /* * We allow the connection to proceed * by generating a detached tcp state vector and put it in * the eager queue. When an accept happens, it will be * dequeued sequentially. */ if ((eager = (tcp_t *)bkmem_alloc(sizeof (tcp_t))) == NULL) { freemsg(mp); errno = ENOBUFS; return (NULL); } if ((errno = tcp_init_values(eager, NULL)) != 0) { freemsg(mp); bkmem_free((caddr_t)eager, sizeof (tcp_t)); return (NULL); } /* * Eager connection inherits address form from its listener, * but its packet form comes from the version of the received * SYN segment. */ eager->tcp_family = tcp->tcp_family; err = tcp_accept_comm(tcp, eager, mp, ip_hdr_len); if (err) { bkmem_free((caddr_t)eager, sizeof (tcp_t)); return (NULL); } tcp->tcp_eager_next_q0->tcp_eager_prev_q0 = eager; eager->tcp_eager_next_q0 = tcp->tcp_eager_next_q0; tcp->tcp_eager_next_q0 = eager; eager->tcp_eager_prev_q0 = tcp; /* Set tcp_listener before adding it to tcp_conn_fanout */ eager->tcp_listener = tcp; tcp->tcp_conn_req_cnt_q0++; return (eager); } /* * To get around the non-interrupt problem of inetboot. * Keep on processing packets until a certain state is reached or the * TCP is destroyed because of getting a RST packet. */ static int tcp_state_wait(int sock_id, tcp_t *tcp, int state) { int i; struct inetgram *in_gram; mblk_t *mp; int timeout; boolean_t changed = B_FALSE; /* * We need to make sure that the MAC does not wait longer * than RTO for any packet so that TCP can do retransmission. * But if the MAC timeout is less than tcp_rto, we are fine * and do not need to change it. */ timeout = sockets[sock_id].in_timeout; if (timeout > tcp->tcp_rto) { sockets[sock_id].in_timeout = tcp->tcp_rto; changed = B_TRUE; } retry: if (sockets[sock_id].inq == NULL) { /* Go out and check the wire */ for (i = MEDIA_LVL; i < TRANSPORT_LVL; i++) { if (sockets[sock_id].input[i] != NULL) { if (sockets[sock_id].input[i](sock_id) < 0) { if (changed) { sockets[sock_id].in_timeout = timeout; } return (-1); } } } } while ((in_gram = sockets[sock_id].inq) != NULL) { if (tcp != NULL && tcp->tcp_state == state) break; /* Remove unknown inetgrams from the head of inq. */ if (in_gram->igm_level != TRANSPORT_LVL) { #ifdef DEBUG printf("tcp_state_wait for state %d: unexpected " "packet level %d frame found\n", state, in_gram->igm_level); #endif del_gram(&sockets[sock_id].inq, in_gram, B_TRUE); continue; } mp = in_gram->igm_mp; del_gram(&sockets[sock_id].inq, in_gram, B_FALSE); bkmem_free((caddr_t)in_gram, sizeof (struct inetgram)); tcp_rput_data(tcp, mp, sock_id); /* * The other side may have closed this connection or * RST us. But we need to continue to process other * packets in the socket's queue because they may be * belong to another TCP connections. */ if (sockets[sock_id].pcb == NULL) { tcp = NULL; } } /* If the other side has closed the connection, just return. */ if (tcp == NULL || sockets[sock_id].pcb == NULL) { #ifdef DEBUG printf("tcp_state_wait other side dead: state %d " "error %d\n", state, sockets[sock_id].so_error); #endif if (sockets[sock_id].so_error != 0) return (-1); else return (0); } /* * TCPS_ALL_ACKED is not a valid TCP state, it is just used as an * indicator to tcp_state_wait to mean that it is being called * to wait till we have received acks for all the new segments sent. */ if ((state == TCPS_ALL_ACKED) && (tcp->tcp_suna == tcp->tcp_snxt)) { goto done; } if (tcp->tcp_state != state) { if (prom_gettime() > tcp->tcp_rto_timeout) tcp_timer(tcp, sock_id); goto retry; } done: if (changed) sockets[sock_id].in_timeout = timeout; tcp_drain_needed(sock_id, tcp); return (0); } /* Verify the checksum of a segment. */ static int tcp_verify_cksum(mblk_t *mp) { struct ip *iph; tcpha_t *tcph; int len; uint16_t old_sum; iph = (struct ip *)mp->b_rptr; tcph = (tcpha_t *)(iph + 1); len = ntohs(iph->ip_len); /* * Calculate the TCP checksum. Need to include the psuedo header, * which is similar to the real IP header starting at the TTL field. */ iph->ip_sum = htons(len - IP_SIMPLE_HDR_LENGTH); old_sum = tcph->tha_sum; tcph->tha_sum = 0; iph->ip_ttl = 0; if (old_sum == tcp_cksum((uint16_t *)&(iph->ip_ttl), len - IP_SIMPLE_HDR_LENGTH + 12)) { return (0); } else { tcp_cksum_errors++; return (-1); } } /* To find a TCP connection matching the incoming segment. */ static tcp_t * tcp_lookup_ipv4(struct ip *iph, tcpha_t *tcph, int min_state, int *sock_id) { int i; tcp_t *tcp; for (i = 0; i < MAXSOCKET; i++) { if (sockets[i].type == INETBOOT_STREAM && (tcp = (tcp_t *)sockets[i].pcb) != NULL) { if (tcph->tha_lport == tcp->tcp_fport && tcph->tha_fport == tcp->tcp_lport && iph->ip_src.s_addr == tcp->tcp_remote && iph->ip_dst.s_addr == tcp->tcp_bound_source && tcp->tcp_state >= min_state) { *sock_id = i; return (tcp); } } } /* Find it in the time wait list. */ for (tcp = tcp_time_wait_head; tcp != NULL; tcp = tcp->tcp_time_wait_next) { if (tcph->tha_lport == tcp->tcp_fport && tcph->tha_fport == tcp->tcp_lport && iph->ip_src.s_addr == tcp->tcp_remote && iph->ip_dst.s_addr == tcp->tcp_bound_source && tcp->tcp_state >= min_state) { *sock_id = -1; return (tcp); } } return (NULL); } /* To find a TCP listening connection matching the incoming segment. */ static tcp_t * tcp_lookup_listener_ipv4(in_addr_t addr, in_port_t port, int *sock_id) { int i; tcp_t *tcp; for (i = 0; i < MAXSOCKET; i++) { if (sockets[i].type == INETBOOT_STREAM && (tcp = (tcp_t *)sockets[i].pcb) != NULL) { if (tcp->tcp_lport == port && (tcp->tcp_bound_source == addr || tcp->tcp_bound_source == INADDR_ANY)) { *sock_id = i; return (tcp); } } } return (NULL); } /* To find a TCP eager matching the incoming segment. */ static tcp_t * tcp_lookup_eager_ipv4(tcp_t *listener, struct ip *iph, tcpha_t *tcph) { tcp_t *tcp; #ifdef DEBUG printf("tcp_lookup_eager_ipv4 ###############\n"); #endif for (tcp = listener->tcp_eager_next_q; tcp != NULL; tcp = tcp->tcp_eager_next_q) { if (tcph->tha_lport == tcp->tcp_fport && tcph->tha_fport == tcp->tcp_lport && iph->ip_src.s_addr == tcp->tcp_remote && iph->ip_dst.s_addr == tcp->tcp_bound_source) { return (tcp); } } for (tcp = listener->tcp_eager_next_q0; tcp != listener; tcp = tcp->tcp_eager_next_q0) { if (tcph->tha_lport == tcp->tcp_fport && tcph->tha_fport == tcp->tcp_lport && iph->ip_src.s_addr == tcp->tcp_remote && iph->ip_dst.s_addr == tcp->tcp_bound_source) { return (tcp); } } #ifdef DEBUG printf("No eager found\n"); #endif return (NULL); } /* To destroy a TCP control block. */ static void tcp_clean_death(int sock_id, tcp_t *tcp, int err) { tcp_free(tcp); if (tcp->tcp_state == TCPS_TIME_WAIT) tcp_time_wait_remove(tcp); if (sock_id >= 0) { sockets[sock_id].pcb = NULL; if (err != 0) sockets[sock_id].so_error = err; } bkmem_free((caddr_t)tcp, sizeof (tcp_t)); } /* * tcp_rwnd_set() is called to adjust the receive window to a desired value. * We do not allow the receive window to shrink. After setting rwnd, * set the flow control hiwat of the stream. * * This function is called in 2 cases: * * 1) Before data transfer begins, in tcp_accept_comm() for accepting a * connection (passive open) and in tcp_rput_data() for active connect. * This is called after tcp_mss_set() when the desired MSS value is known. * This makes sure that our window size is a mutiple of the other side's * MSS. * 2) Handling SO_RCVBUF option. * * It is ASSUMED that the requested size is a multiple of the current MSS. * * XXX - Should allow a lower rwnd than tcp_recv_hiwat_minmss * mss if the * user requests so. */ static int tcp_rwnd_set(tcp_t *tcp, uint32_t rwnd) { uint32_t mss = tcp->tcp_mss; uint32_t old_max_rwnd; uint32_t max_transmittable_rwnd; if (tcp->tcp_rwnd_max != 0) old_max_rwnd = tcp->tcp_rwnd_max; else old_max_rwnd = tcp->tcp_rwnd; /* * Insist on a receive window that is at least * tcp_recv_hiwat_minmss * MSS (default 4 * MSS) to avoid * funny TCP interactions of Nagle algorithm, SWS avoidance * and delayed acknowledgement. */ rwnd = MAX(rwnd, tcp_recv_hiwat_minmss * mss); /* * If window size info has already been exchanged, TCP should not * shrink the window. Shrinking window is doable if done carefully. * We may add that support later. But so far there is not a real * need to do that. */ if (rwnd < old_max_rwnd && tcp->tcp_state > TCPS_SYN_SENT) { /* MSS may have changed, do a round up again. */ rwnd = MSS_ROUNDUP(old_max_rwnd, mss); } /* * tcp_rcv_ws starts with TCP_MAX_WINSHIFT so the following check * can be applied even before the window scale option is decided. */ max_transmittable_rwnd = TCP_MAXWIN << tcp->tcp_rcv_ws; if (rwnd > max_transmittable_rwnd) { rwnd = max_transmittable_rwnd - (max_transmittable_rwnd % mss); if (rwnd < mss) rwnd = max_transmittable_rwnd; /* * If we're over the limit we may have to back down tcp_rwnd. * The increment below won't work for us. So we set all three * here and the increment below will have no effect. */ tcp->tcp_rwnd = old_max_rwnd = rwnd; } /* * Increment the current rwnd by the amount the maximum grew (we * can not overwrite it since we might be in the middle of a * connection.) */ tcp->tcp_rwnd += rwnd - old_max_rwnd; U32_TO_ABE16(tcp->tcp_rwnd >> tcp->tcp_rcv_ws, tcp->tcp_tcph->th_win); if ((tcp->tcp_rcv_ws > 0) && rwnd > tcp->tcp_cwnd_max) tcp->tcp_cwnd_max = rwnd; tcp->tcp_rwnd_max = rwnd; return (rwnd); } /* * Extract option values from a tcp header. We put any found values into the * tcpopt struct and return a bitmask saying which options were found. */ static int tcp_parse_options(tcph_t *tcph, tcp_opt_t *tcpopt) { uchar_t *endp; int len; uint32_t mss; uchar_t *up = (uchar_t *)tcph; int found = 0; int32_t sack_len; tcp_seq sack_begin, sack_end; tcp_t *tcp; endp = up + TCP_HDR_LENGTH(tcph); up += TCP_MIN_HEADER_LENGTH; while (up < endp) { len = endp - up; switch (*up) { case TCPOPT_EOL: break; case TCPOPT_NOP: up++; continue; case TCPOPT_MAXSEG: if (len < TCPOPT_MAXSEG_LEN || up[1] != TCPOPT_MAXSEG_LEN) break; mss = BE16_TO_U16(up+2); /* Caller must handle tcp_mss_min and tcp_mss_max_* */ tcpopt->tcp_opt_mss = mss; found |= TCP_OPT_MSS_PRESENT; up += TCPOPT_MAXSEG_LEN; continue; case TCPOPT_WSCALE: if (len < TCPOPT_WS_LEN || up[1] != TCPOPT_WS_LEN) break; if (up[2] > TCP_MAX_WINSHIFT) tcpopt->tcp_opt_wscale = TCP_MAX_WINSHIFT; else tcpopt->tcp_opt_wscale = up[2]; found |= TCP_OPT_WSCALE_PRESENT; up += TCPOPT_WS_LEN; continue; case TCPOPT_SACK_PERMITTED: if (len < TCPOPT_SACK_OK_LEN || up[1] != TCPOPT_SACK_OK_LEN) break; found |= TCP_OPT_SACK_OK_PRESENT; up += TCPOPT_SACK_OK_LEN; continue; case TCPOPT_SACK: if (len <= 2 || up[1] <= 2 || len < up[1]) break; /* If TCP is not interested in SACK blks... */ if ((tcp = tcpopt->tcp) == NULL) { up += up[1]; continue; } sack_len = up[1] - TCPOPT_HEADER_LEN; up += TCPOPT_HEADER_LEN; /* * If the list is empty, allocate one and assume * nothing is sack'ed. */ assert(tcp->tcp_sack_info != NULL); if (tcp->tcp_notsack_list == NULL) { tcp_notsack_update(&(tcp->tcp_notsack_list), tcp->tcp_suna, tcp->tcp_snxt, &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list)); /* * Make sure tcp_notsack_list is not NULL. * This happens when kmem_alloc(KM_NOSLEEP) * returns NULL. */ if (tcp->tcp_notsack_list == NULL) { up += sack_len; continue; } tcp->tcp_fack = tcp->tcp_suna; } while (sack_len > 0) { if (up + 8 > endp) { up = endp; break; } sack_begin = BE32_TO_U32(up); up += 4; sack_end = BE32_TO_U32(up); up += 4; sack_len -= 8; /* * Bounds checking. Make sure the SACK * info is within tcp_suna and tcp_snxt. * If this SACK blk is out of bound, ignore * it but continue to parse the following * blks. */ if (SEQ_LEQ(sack_end, sack_begin) || SEQ_LT(sack_begin, tcp->tcp_suna) || SEQ_GT(sack_end, tcp->tcp_snxt)) { continue; } tcp_notsack_insert(&(tcp->tcp_notsack_list), sack_begin, sack_end, &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list)); if (SEQ_GT(sack_end, tcp->tcp_fack)) { tcp->tcp_fack = sack_end; } } found |= TCP_OPT_SACK_PRESENT; continue; case TCPOPT_TSTAMP: if (len < TCPOPT_TSTAMP_LEN || up[1] != TCPOPT_TSTAMP_LEN) break; tcpopt->tcp_opt_ts_val = BE32_TO_U32(up+2); tcpopt->tcp_opt_ts_ecr = BE32_TO_U32(up+6); found |= TCP_OPT_TSTAMP_PRESENT; up += TCPOPT_TSTAMP_LEN; continue; default: if (len <= 1 || len < (int)up[1] || up[1] == 0) break; up += up[1]; continue; } break; } return (found); } /* * Set the mss associated with a particular tcp based on its current value, * and a new one passed in. Observe minimums and maximums, and reset * other state variables that we want to view as multiples of mss. * * This function is called in various places mainly because * 1) Various stuffs, tcp_mss, tcp_cwnd, ... need to be adjusted when the * other side's SYN/SYN-ACK packet arrives. * 2) PMTUd may get us a new MSS. * 3) If the other side stops sending us timestamp option, we need to * increase the MSS size to use the extra bytes available. */ static void tcp_mss_set(tcp_t *tcp, uint32_t mss) { uint32_t mss_max; mss_max = tcp_mss_max_ipv4; if (mss < tcp_mss_min) mss = tcp_mss_min; if (mss > mss_max) mss = mss_max; /* * Unless naglim has been set by our client to * a non-mss value, force naglim to track mss. * This can help to aggregate small writes. */ if (mss < tcp->tcp_naglim || tcp->tcp_mss == tcp->tcp_naglim) tcp->tcp_naglim = mss; /* * TCP should be able to buffer at least 4 MSS data for obvious * performance reason. */ if ((mss << 2) > tcp->tcp_xmit_hiwater) tcp->tcp_xmit_hiwater = mss << 2; tcp->tcp_mss = mss; /* * Initialize cwnd according to draft-floyd-incr-init-win-01.txt. * Previously, we use tcp_slow_start_initial to control the size * of the initial cwnd. Now, when tcp_slow_start_initial * mss * is smaller than the cwnd calculated from the formula suggested in * the draft, we use tcp_slow_start_initial * mss as the cwnd. * Otherwise, use the cwnd from the draft's formula. The default * of tcp_slow_start_initial is 2. */ tcp->tcp_cwnd = MIN(tcp_slow_start_initial * mss, MIN(4 * mss, MAX(2 * mss, 4380 / mss * mss))); tcp->tcp_cwnd_cnt = 0; } /* * Process all TCP option in SYN segment. * * This function sets up the correct tcp_mss value according to the * MSS option value and our header size. It also sets up the window scale * and timestamp values, and initialize SACK info blocks. But it does not * change receive window size after setting the tcp_mss value. The caller * should do the appropriate change. */ void tcp_process_options(tcp_t *tcp, tcph_t *tcph) { int options; tcp_opt_t tcpopt; uint32_t mss_max; char *tmp_tcph; tcpopt.tcp = NULL; options = tcp_parse_options(tcph, &tcpopt); /* * Process MSS option. Note that MSS option value does not account * for IP or TCP options. This means that it is equal to MTU - minimum * IP+TCP header size, which is 40 bytes for IPv4 and 60 bytes for * IPv6. */ if (!(options & TCP_OPT_MSS_PRESENT)) { tcpopt.tcp_opt_mss = tcp_mss_def_ipv4; } else { if (tcp->tcp_ipversion == IPV4_VERSION) mss_max = tcp_mss_max_ipv4; if (tcpopt.tcp_opt_mss < tcp_mss_min) tcpopt.tcp_opt_mss = tcp_mss_min; else if (tcpopt.tcp_opt_mss > mss_max) tcpopt.tcp_opt_mss = mss_max; } /* Process Window Scale option. */ if (options & TCP_OPT_WSCALE_PRESENT) { tcp->tcp_snd_ws = tcpopt.tcp_opt_wscale; tcp->tcp_snd_ws_ok = B_TRUE; } else { tcp->tcp_snd_ws = B_FALSE; tcp->tcp_snd_ws_ok = B_FALSE; tcp->tcp_rcv_ws = B_FALSE; } /* Process Timestamp option. */ if ((options & TCP_OPT_TSTAMP_PRESENT) && (tcp->tcp_snd_ts_ok || !tcp->tcp_active_open)) { tmp_tcph = (char *)tcp->tcp_tcph; tcp->tcp_snd_ts_ok = B_TRUE; tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val; tcp->tcp_last_rcv_lbolt = prom_gettime(); assert(OK_32PTR(tmp_tcph)); assert(tcp->tcp_tcp_hdr_len == TCP_MIN_HEADER_LENGTH); /* Fill in our template header with basic timestamp option. */ tmp_tcph += tcp->tcp_tcp_hdr_len; tmp_tcph[0] = TCPOPT_NOP; tmp_tcph[1] = TCPOPT_NOP; tmp_tcph[2] = TCPOPT_TSTAMP; tmp_tcph[3] = TCPOPT_TSTAMP_LEN; tcp->tcp_hdr_len += TCPOPT_REAL_TS_LEN; tcp->tcp_tcp_hdr_len += TCPOPT_REAL_TS_LEN; tcp->tcp_tcph->th_offset_and_rsrvd[0] += (3 << 4); } else { tcp->tcp_snd_ts_ok = B_FALSE; } /* * Process SACK options. If SACK is enabled for this connection, * then allocate the SACK info structure. */ if ((options & TCP_OPT_SACK_OK_PRESENT) && (tcp->tcp_snd_sack_ok || (tcp_sack_permitted != 0 && !tcp->tcp_active_open))) { /* This should be true only in the passive case. */ if (tcp->tcp_sack_info == NULL) { tcp->tcp_sack_info = (tcp_sack_info_t *)bkmem_zalloc( sizeof (tcp_sack_info_t)); } if (tcp->tcp_sack_info == NULL) { tcp->tcp_snd_sack_ok = B_FALSE; } else { tcp->tcp_snd_sack_ok = B_TRUE; if (tcp->tcp_snd_ts_ok) { tcp->tcp_max_sack_blk = 3; } else { tcp->tcp_max_sack_blk = 4; } } } else { /* * Resetting tcp_snd_sack_ok to B_FALSE so that * no SACK info will be used for this * connection. This assumes that SACK usage * permission is negotiated. This may need * to be changed once this is clarified. */ if (tcp->tcp_sack_info != NULL) { bkmem_free((caddr_t)tcp->tcp_sack_info, sizeof (tcp_sack_info_t)); tcp->tcp_sack_info = NULL; } tcp->tcp_snd_sack_ok = B_FALSE; } /* * Now we know the exact TCP/IP header length, subtract * that from tcp_mss to get our side's MSS. */ tcp->tcp_mss -= tcp->tcp_hdr_len; /* * Here we assume that the other side's header size will be equal to * our header size. We calculate the real MSS accordingly. Need to * take into additional stuffs IPsec puts in. * * Real MSS = Opt.MSS - (our TCP/IP header - min TCP/IP header) */ tcpopt.tcp_opt_mss -= tcp->tcp_hdr_len - (IP_SIMPLE_HDR_LENGTH + TCP_MIN_HEADER_LENGTH); /* * Set MSS to the smaller one of both ends of the connection. * We should not have called tcp_mss_set() before, but our * side of the MSS should have been set to a proper value * by tcp_adapt_ire(). tcp_mss_set() will also set up the * STREAM head parameters properly. * * If we have a larger-than-16-bit window but the other side * didn't want to do window scale, tcp_rwnd_set() will take * care of that. */ tcp_mss_set(tcp, MIN(tcpopt.tcp_opt_mss, tcp->tcp_mss)); } /* * This function does PAWS protection check. Returns B_TRUE if the * segment passes the PAWS test, else returns B_FALSE. */ boolean_t tcp_paws_check(tcp_t *tcp, tcph_t *tcph, tcp_opt_t *tcpoptp) { uint8_t flags; int options; uint8_t *up; flags = (unsigned int)tcph->th_flags[0] & 0xFF; /* * If timestamp option is aligned nicely, get values inline, * otherwise call general routine to parse. Only do that * if timestamp is the only option. */ if (TCP_HDR_LENGTH(tcph) == (uint32_t)TCP_MIN_HEADER_LENGTH + TCPOPT_REAL_TS_LEN && OK_32PTR((up = ((uint8_t *)tcph) + TCP_MIN_HEADER_LENGTH)) && *(uint32_t *)up == TCPOPT_NOP_NOP_TSTAMP) { tcpoptp->tcp_opt_ts_val = ABE32_TO_U32((up+4)); tcpoptp->tcp_opt_ts_ecr = ABE32_TO_U32((up+8)); options = TCP_OPT_TSTAMP_PRESENT; } else { if (tcp->tcp_snd_sack_ok) { tcpoptp->tcp = tcp; } else { tcpoptp->tcp = NULL; } options = tcp_parse_options(tcph, tcpoptp); } if (options & TCP_OPT_TSTAMP_PRESENT) { /* * Do PAWS per RFC 1323 section 4.2. Accept RST * regardless of the timestamp, page 18 RFC 1323.bis. */ if ((flags & TH_RST) == 0 && TSTMP_LT(tcpoptp->tcp_opt_ts_val, tcp->tcp_ts_recent)) { if (TSTMP_LT(prom_gettime(), tcp->tcp_last_rcv_lbolt + PAWS_TIMEOUT)) { /* This segment is not acceptable. */ return (B_FALSE); } else { /* * Connection has been idle for * too long. Reset the timestamp * and assume the segment is valid. */ tcp->tcp_ts_recent = tcpoptp->tcp_opt_ts_val; } } } else { /* * If we don't get a timestamp on every packet, we * figure we can't really trust 'em, so we stop sending * and parsing them. */ tcp->tcp_snd_ts_ok = B_FALSE; tcp->tcp_hdr_len -= TCPOPT_REAL_TS_LEN; tcp->tcp_tcp_hdr_len -= TCPOPT_REAL_TS_LEN; tcp->tcp_tcph->th_offset_and_rsrvd[0] -= (3 << 4); tcp_mss_set(tcp, tcp->tcp_mss + TCPOPT_REAL_TS_LEN); if (tcp->tcp_snd_sack_ok) { assert(tcp->tcp_sack_info != NULL); tcp->tcp_max_sack_blk = 4; } } return (B_TRUE); } /* * tcp_get_seg_mp() is called to get the pointer to a segment in the * send queue which starts at the given seq. no. * * Parameters: * tcp_t *tcp: the tcp instance pointer. * uint32_t seq: the starting seq. no of the requested segment. * int32_t *off: after the execution, *off will be the offset to * the returned mblk which points to the requested seq no. * * Return: * A mblk_t pointer pointing to the requested segment in send queue. */ static mblk_t * tcp_get_seg_mp(tcp_t *tcp, uint32_t seq, int32_t *off) { int32_t cnt; mblk_t *mp; /* Defensive coding. Make sure we don't send incorrect data. */ if (SEQ_LT(seq, tcp->tcp_suna) || SEQ_GEQ(seq, tcp->tcp_snxt) || off == NULL) { return (NULL); } cnt = seq - tcp->tcp_suna; mp = tcp->tcp_xmit_head; while (cnt > 0 && mp) { cnt -= mp->b_wptr - mp->b_rptr; if (cnt < 0) { cnt += mp->b_wptr - mp->b_rptr; break; } mp = mp->b_cont; } assert(mp != NULL); *off = cnt; return (mp); } /* * This function handles all retransmissions if SACK is enabled for this * connection. First it calculates how many segments can be retransmitted * based on tcp_pipe. Then it goes thru the notsack list to find eligible * segments. A segment is eligible if sack_cnt for that segment is greater * than or equal tcp_dupack_fast_retransmit. After it has retransmitted * all eligible segments, it checks to see if TCP can send some new segments * (fast recovery). If it can, it returns 1. Otherwise it returns 0. * * Parameters: * tcp_t *tcp: the tcp structure of the connection. * * Return: * 1 if the pipe is not full (new data can be sent), 0 otherwise */ static int32_t tcp_sack_rxmit(tcp_t *tcp, int sock_id) { notsack_blk_t *notsack_blk; int32_t usable_swnd; int32_t mss; uint32_t seg_len; mblk_t *xmit_mp; assert(tcp->tcp_sack_info != NULL); assert(tcp->tcp_notsack_list != NULL); assert(tcp->tcp_rexmit == B_FALSE); /* Defensive coding in case there is a bug... */ if (tcp->tcp_notsack_list == NULL) { return (0); } notsack_blk = tcp->tcp_notsack_list; mss = tcp->tcp_mss; /* * Limit the num of outstanding data in the network to be * tcp_cwnd_ssthresh, which is half of the original congestion wnd. */ usable_swnd = tcp->tcp_cwnd_ssthresh - tcp->tcp_pipe; /* At least retransmit 1 MSS of data. */ if (usable_swnd <= 0) { usable_swnd = mss; } /* Make sure no new RTT samples will be taken. */ tcp->tcp_csuna = tcp->tcp_snxt; notsack_blk = tcp->tcp_notsack_list; while (usable_swnd > 0) { mblk_t *snxt_mp, *tmp_mp; tcp_seq begin = tcp->tcp_sack_snxt; tcp_seq end; int32_t off; for (; notsack_blk != NULL; notsack_blk = notsack_blk->next) { if (SEQ_GT(notsack_blk->end, begin) && (notsack_blk->sack_cnt >= tcp_dupack_fast_retransmit)) { end = notsack_blk->end; if (SEQ_LT(begin, notsack_blk->begin)) { begin = notsack_blk->begin; } break; } } /* * All holes are filled. Manipulate tcp_cwnd to send more * if we can. Note that after the SACK recovery, tcp_cwnd is * set to tcp_cwnd_ssthresh. */ if (notsack_blk == NULL) { usable_swnd = tcp->tcp_cwnd_ssthresh - tcp->tcp_pipe; if (usable_swnd <= 0) { tcp->tcp_cwnd = tcp->tcp_snxt - tcp->tcp_suna; assert(tcp->tcp_cwnd > 0); return (0); } else { usable_swnd = usable_swnd / mss; tcp->tcp_cwnd = tcp->tcp_snxt - tcp->tcp_suna + MAX(usable_swnd * mss, mss); return (1); } } /* * Note that we may send more than usable_swnd allows here * because of round off, but no more than 1 MSS of data. */ seg_len = end - begin; if (seg_len > mss) seg_len = mss; snxt_mp = tcp_get_seg_mp(tcp, begin, &off); assert(snxt_mp != NULL); /* This should not happen. Defensive coding again... */ if (snxt_mp == NULL) { return (0); } xmit_mp = tcp_xmit_mp(tcp, snxt_mp, seg_len, &off, &tmp_mp, begin, B_TRUE, &seg_len, B_TRUE); if (xmit_mp == NULL) return (0); usable_swnd -= seg_len; tcp->tcp_pipe += seg_len; tcp->tcp_sack_snxt = begin + seg_len; TCP_DUMP_PACKET("tcp_sack_rxmit", xmit_mp); (void) ipv4_tcp_output(sock_id, xmit_mp); freeb(xmit_mp); /* * Update the send timestamp to avoid false retransmission. * Note. use uintptr_t to suppress the gcc warning. */ snxt_mp->b_prev = (mblk_t *)(uintptr_t)prom_gettime(); BUMP_MIB(tcp_mib.tcpRetransSegs); UPDATE_MIB(tcp_mib.tcpRetransBytes, seg_len); BUMP_MIB(tcp_mib.tcpOutSackRetransSegs); /* * Update tcp_rexmit_max to extend this SACK recovery phase. * This happens when new data sent during fast recovery is * also lost. If TCP retransmits those new data, it needs * to extend SACK recover phase to avoid starting another * fast retransmit/recovery unnecessarily. */ if (SEQ_GT(tcp->tcp_sack_snxt, tcp->tcp_rexmit_max)) { tcp->tcp_rexmit_max = tcp->tcp_sack_snxt; } } return (0); } static void tcp_rput_data(tcp_t *tcp, mblk_t *mp, int sock_id) { uchar_t *rptr; struct ip *iph; tcp_t *tcp1; tcpha_t *tcph; uint32_t seg_ack; int seg_len; uint_t ip_hdr_len; uint32_t seg_seq; mblk_t *mp1; uint_t flags; uint32_t new_swnd = 0; int mss; boolean_t ofo_seg = B_FALSE; /* Out of order segment */ int32_t gap; int32_t rgap; tcp_opt_t tcpopt; int32_t bytes_acked; int npkt; uint32_t cwnd; uint32_t add; #ifdef DEBUG printf("tcp_rput_data sock %d mp %x mp_datap %x #################\n", sock_id, mp, mp->b_datap); #endif /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_rput_data", mp); assert(OK_32PTR(mp->b_rptr)); rptr = mp->b_rptr; iph = (struct ip *)rptr; ip_hdr_len = IPH_HDR_LENGTH(rptr); if (ip_hdr_len != IP_SIMPLE_HDR_LENGTH) { #ifdef DEBUG printf("Not simple IP header\n"); #endif /* We cannot handle IP option yet... */ tcp_drops++; freeb(mp); return; } /* The TCP header must be aligned. */ tcph = (tcpha_t *)&rptr[ip_hdr_len]; seg_seq = ntohl(tcph->tha_seq); seg_ack = ntohl(tcph->tha_ack); assert((uintptr_t)(mp->b_wptr - rptr) <= (uintptr_t)INT_MAX); seg_len = (int)(mp->b_wptr - rptr) - (ip_hdr_len + TCP_HDR_LENGTH(((tcph_t *)tcph))); /* In inetboot, b_cont should always be NULL. */ assert(mp->b_cont == NULL); /* Verify the checksum. */ if (tcp_verify_cksum(mp) < 0) { #ifdef DEBUG printf("tcp_rput_data: wrong cksum\n"); #endif freemsg(mp); return; } /* * This segment is not for us, try to find its * intended receiver. */ if (tcp == NULL || tcph->tha_lport != tcp->tcp_fport || tcph->tha_fport != tcp->tcp_lport || iph->ip_src.s_addr != tcp->tcp_remote || iph->ip_dst.s_addr != tcp->tcp_bound_source) { #ifdef DEBUG printf("tcp_rput_data: not for us, state %d\n", tcp->tcp_state); #endif /* * First try to find a established connection. If none * is found, look for a listener. * * If a listener is found, we need to check to see if the * incoming segment is for one of its eagers. If it is, * give it to the eager. If not, listener should take care * of it. */ if ((tcp1 = tcp_lookup_ipv4(iph, tcph, TCPS_SYN_SENT, &sock_id)) != NULL || (tcp1 = tcp_lookup_listener_ipv4(iph->ip_dst.s_addr, tcph->tha_fport, &sock_id)) != NULL) { if (tcp1->tcp_state == TCPS_LISTEN) { if ((tcp = tcp_lookup_eager_ipv4(tcp1, iph, tcph)) == NULL) { /* No eager... sent to listener */ #ifdef DEBUG printf("found the listener: %s\n", tcp_display(tcp1, NULL, DISP_ADDR_AND_PORT)); #endif tcp = tcp1; } #ifdef DEBUG else { printf("found the eager: %s\n", tcp_display(tcp, NULL, DISP_ADDR_AND_PORT)); } #endif } else { /* Non listener found... */ #ifdef DEBUG printf("found the connection: %s\n", tcp_display(tcp1, NULL, DISP_ADDR_AND_PORT)); #endif tcp = tcp1; } } else { /* * No connection for this segment... * Send a RST to the other side. */ tcp_xmit_listeners_reset(sock_id, mp, ip_hdr_len); return; } } flags = tcph->tha_flags & 0xFF; BUMP_MIB(tcp_mib.tcpInSegs); if (tcp->tcp_state == TCPS_TIME_WAIT) { tcp_time_wait_processing(tcp, mp, seg_seq, seg_ack, seg_len, (tcph_t *)tcph, sock_id); return; } /* * From this point we can assume that the tcp is not compressed, * since we would have branched off to tcp_time_wait_processing() * in such a case. */ assert(tcp != NULL && tcp->tcp_state != TCPS_TIME_WAIT); /* * After this point, we know we have the correct TCP, so update * the receive time. */ tcp->tcp_last_recv_time = prom_gettime(); /* In inetboot, we do not handle urgent pointer... */ if (flags & TH_URG) { freemsg(mp); DEBUG_1("tcp_rput_data(%d): received segment with urgent " "pointer\n", sock_id); tcp_drops++; return; } switch (tcp->tcp_state) { case TCPS_LISTEN: if ((flags & (TH_RST | TH_ACK | TH_SYN)) != TH_SYN) { if (flags & TH_RST) { freemsg(mp); return; } if (flags & TH_ACK) { tcp_xmit_early_reset("TCPS_LISTEN-TH_ACK", sock_id, mp, seg_ack, 0, TH_RST, ip_hdr_len); return; } if (!(flags & TH_SYN)) { freemsg(mp); return; } printf("tcp_rput_data: %d\n", __LINE__); prom_panic("inetboot"); } if (tcp->tcp_conn_req_max > 0) { tcp = tcp_conn_request(tcp, mp, sock_id, ip_hdr_len); if (tcp == NULL) { freemsg(mp); return; } #ifdef DEBUG printf("tcp_rput_data: new tcp created\n"); #endif } tcp->tcp_irs = seg_seq; tcp->tcp_rack = seg_seq; tcp->tcp_rnxt = seg_seq + 1; U32_TO_ABE32(tcp->tcp_rnxt, tcp->tcp_tcph->th_ack); BUMP_MIB(tcp_mib.tcpPassiveOpens); goto syn_rcvd; case TCPS_SYN_SENT: if (flags & TH_ACK) { /* * Note that our stack cannot send data before a * connection is established, therefore the * following check is valid. Otherwise, it has * to be changed. */ if (SEQ_LEQ(seg_ack, tcp->tcp_iss) || SEQ_GT(seg_ack, tcp->tcp_snxt)) { if (flags & TH_RST) { freemsg(mp); return; } tcp_xmit_ctl("TCPS_SYN_SENT-Bad_seq", tcp, mp, seg_ack, 0, TH_RST, ip_hdr_len, sock_id); return; } assert(tcp->tcp_suna + 1 == seg_ack); } if (flags & TH_RST) { freemsg(mp); if (flags & TH_ACK) { tcp_clean_death(sock_id, tcp, ECONNREFUSED); } return; } if (!(flags & TH_SYN)) { freemsg(mp); return; } /* Process all TCP options. */ tcp_process_options(tcp, (tcph_t *)tcph); /* * The following changes our rwnd to be a multiple of the * MIN(peer MSS, our MSS) for performance reason. */ (void) tcp_rwnd_set(tcp, MSS_ROUNDUP(tcp->tcp_rwnd, tcp->tcp_mss)); /* Is the other end ECN capable? */ if (tcp->tcp_ecn_ok) { if ((flags & (TH_ECE|TH_CWR)) != TH_ECE) { tcp->tcp_ecn_ok = B_FALSE; } } /* * Clear ECN flags because it may interfere with later * processing. */ flags &= ~(TH_ECE|TH_CWR); tcp->tcp_irs = seg_seq; tcp->tcp_rack = seg_seq; tcp->tcp_rnxt = seg_seq + 1; U32_TO_ABE32(tcp->tcp_rnxt, tcp->tcp_tcph->th_ack); if (flags & TH_ACK) { /* One for the SYN */ tcp->tcp_suna = tcp->tcp_iss + 1; tcp->tcp_valid_bits &= ~TCP_ISS_VALID; tcp->tcp_state = TCPS_ESTABLISHED; /* * If SYN was retransmitted, need to reset all * retransmission info. This is because this * segment will be treated as a dup ACK. */ if (tcp->tcp_rexmit) { tcp->tcp_rexmit = B_FALSE; tcp->tcp_rexmit_nxt = tcp->tcp_snxt; tcp->tcp_rexmit_max = tcp->tcp_snxt; tcp->tcp_snd_burst = TCP_CWND_NORMAL; /* * Set tcp_cwnd back to 1 MSS, per * recommendation from * draft-floyd-incr-init-win-01.txt, * Increasing TCP's Initial Window. */ tcp->tcp_cwnd = tcp->tcp_mss; } tcp->tcp_swl1 = seg_seq; tcp->tcp_swl2 = seg_ack; new_swnd = BE16_TO_U16(((tcph_t *)tcph)->th_win); tcp->tcp_swnd = new_swnd; if (new_swnd > tcp->tcp_max_swnd) tcp->tcp_max_swnd = new_swnd; /* * Always send the three-way handshake ack immediately * in order to make the connection complete as soon as * possible on the accepting host. */ flags |= TH_ACK_NEEDED; /* * Check to see if there is data to be sent. If * yes, set the transmit flag. Then check to see * if received data processing needs to be done. * If not, go straight to xmit_check. This short * cut is OK as we don't support T/TCP. */ if (tcp->tcp_unsent) flags |= TH_XMIT_NEEDED; if (seg_len == 0) { freemsg(mp); goto xmit_check; } flags &= ~TH_SYN; seg_seq++; break; } syn_rcvd: tcp->tcp_state = TCPS_SYN_RCVD; mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, tcp->tcp_mss, NULL, NULL, tcp->tcp_iss, B_FALSE, NULL, B_FALSE); if (mp1 != NULL) { TCP_DUMP_PACKET("tcp_rput_data replying SYN", mp1); (void) ipv4_tcp_output(sock_id, mp1); TCP_TIMER_RESTART(tcp, tcp->tcp_rto); freeb(mp1); /* * Let's wait till our SYN has been ACKED since we * don't have a timer. */ if (tcp_state_wait(sock_id, tcp, TCPS_ALL_ACKED) < 0) { freemsg(mp); return; } } freemsg(mp); return; default: break; } mp->b_rptr = (uchar_t *)tcph + TCP_HDR_LENGTH((tcph_t *)tcph); new_swnd = ntohs(tcph->tha_win) << ((flags & TH_SYN) ? 0 : tcp->tcp_snd_ws); mss = tcp->tcp_mss; if (tcp->tcp_snd_ts_ok) { if (!tcp_paws_check(tcp, (tcph_t *)tcph, &tcpopt)) { /* * This segment is not acceptable. * Drop it and send back an ACK. */ freemsg(mp); flags |= TH_ACK_NEEDED; goto ack_check; } } else if (tcp->tcp_snd_sack_ok) { assert(tcp->tcp_sack_info != NULL); tcpopt.tcp = tcp; /* * SACK info in already updated in tcp_parse_options. Ignore * all other TCP options... */ (void) tcp_parse_options((tcph_t *)tcph, &tcpopt); } try_again:; gap = seg_seq - tcp->tcp_rnxt; rgap = tcp->tcp_rwnd - (gap + seg_len); /* * gap is the amount of sequence space between what we expect to see * and what we got for seg_seq. A positive value for gap means * something got lost. A negative value means we got some old stuff. */ if (gap < 0) { /* Old stuff present. Is the SYN in there? */ if (seg_seq == tcp->tcp_irs && (flags & TH_SYN) && (seg_len != 0)) { flags &= ~TH_SYN; seg_seq++; /* Recompute the gaps after noting the SYN. */ goto try_again; } BUMP_MIB(tcp_mib.tcpInDataDupSegs); UPDATE_MIB(tcp_mib.tcpInDataDupBytes, (seg_len > -gap ? -gap : seg_len)); /* Remove the old stuff from seg_len. */ seg_len += gap; /* * Anything left? * Make sure to check for unack'd FIN when rest of data * has been previously ack'd. */ if (seg_len < 0 || (seg_len == 0 && !(flags & TH_FIN))) { /* * Resets are only valid if they lie within our offered * window. If the RST bit is set, we just ignore this * segment. */ if (flags & TH_RST) { freemsg(mp); return; } /* * This segment is "unacceptable". None of its * sequence space lies within our advertized window. * * Adjust seg_len to the original value for tracing. */ seg_len -= gap; #ifdef DEBUG printf("tcp_rput: unacceptable, gap %d, rgap " "%d, flags 0x%x, seg_seq %u, seg_ack %u, " "seg_len %d, rnxt %u, snxt %u, %s", gap, rgap, flags, seg_seq, seg_ack, seg_len, tcp->tcp_rnxt, tcp->tcp_snxt, tcp_display(tcp, NULL, DISP_ADDR_AND_PORT)); #endif /* * Arrange to send an ACK in response to the * unacceptable segment per RFC 793 page 69. There * is only one small difference between ours and the * acceptability test in the RFC - we accept ACK-only * packet with SEG.SEQ = RCV.NXT+RCV.WND and no ACK * will be generated. * * Note that we have to ACK an ACK-only packet at least * for stacks that send 0-length keep-alives with * SEG.SEQ = SND.NXT-1 as recommended by RFC1122, * section 4.2.3.6. As long as we don't ever generate * an unacceptable packet in response to an incoming * packet that is unacceptable, it should not cause * "ACK wars". */ flags |= TH_ACK_NEEDED; /* * Continue processing this segment in order to use the * ACK information it contains, but skip all other * sequence-number processing. Processing the ACK * information is necessary in order to * re-synchronize connections that may have lost * synchronization. * * We clear seg_len and flag fields related to * sequence number processing as they are not * to be trusted for an unacceptable segment. */ seg_len = 0; flags &= ~(TH_SYN | TH_FIN | TH_URG); goto process_ack; } /* Fix seg_seq, and chew the gap off the front. */ seg_seq = tcp->tcp_rnxt; do { mblk_t *mp2; assert((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)UINT_MAX); gap += (uint_t)(mp->b_wptr - mp->b_rptr); if (gap > 0) { mp->b_rptr = mp->b_wptr - gap; break; } mp2 = mp; mp = mp->b_cont; freeb(mp2); } while (gap < 0); } /* * rgap is the amount of stuff received out of window. A negative * value is the amount out of window. */ if (rgap < 0) { mblk_t *mp2; if (tcp->tcp_rwnd == 0) BUMP_MIB(tcp_mib.tcpInWinProbe); else { BUMP_MIB(tcp_mib.tcpInDataPastWinSegs); UPDATE_MIB(tcp_mib.tcpInDataPastWinBytes, -rgap); } /* * seg_len does not include the FIN, so if more than * just the FIN is out of window, we act like we don't * see it. (If just the FIN is out of window, rgap * will be zero and we will go ahead and acknowledge * the FIN.) */ flags &= ~TH_FIN; /* Fix seg_len and make sure there is something left. */ seg_len += rgap; if (seg_len <= 0) { /* * Resets are only valid if they lie within our offered * window. If the RST bit is set, we just ignore this * segment. */ if (flags & TH_RST) { freemsg(mp); return; } /* Per RFC 793, we need to send back an ACK. */ flags |= TH_ACK_NEEDED; /* * If this is a zero window probe, continue to * process the ACK part. But we need to set seg_len * to 0 to avoid data processing. Otherwise just * drop the segment and send back an ACK. */ if (tcp->tcp_rwnd == 0 && seg_seq == tcp->tcp_rnxt) { flags &= ~(TH_SYN | TH_URG); seg_len = 0; /* Let's see if we can update our rwnd */ tcp_rcv_drain(sock_id, tcp); goto process_ack; } else { freemsg(mp); goto ack_check; } } /* Pitch out of window stuff off the end. */ rgap = seg_len; mp2 = mp; do { assert((uintptr_t)(mp2->b_wptr - mp2->b_rptr) <= (uintptr_t)INT_MAX); rgap -= (int)(mp2->b_wptr - mp2->b_rptr); if (rgap < 0) { mp2->b_wptr += rgap; if ((mp1 = mp2->b_cont) != NULL) { mp2->b_cont = NULL; freemsg(mp1); } break; } } while ((mp2 = mp2->b_cont) != NULL); } ok:; /* * TCP should check ECN info for segments inside the window only. * Therefore the check should be done here. */ if (tcp->tcp_ecn_ok) { uchar_t tos = ((struct ip *)rptr)->ip_tos; if (flags & TH_CWR) { tcp->tcp_ecn_echo_on = B_FALSE; } /* * Note that both ECN_CE and CWR can be set in the * same segment. In this case, we once again turn * on ECN_ECHO. */ if ((tos & IPH_ECN_CE) == IPH_ECN_CE) { tcp->tcp_ecn_echo_on = B_TRUE; } } /* * Check whether we can update tcp_ts_recent. This test is * NOT the one in RFC 1323 3.4. It is from Braden, 1993, "TCP * Extensions for High Performance: An Update", Internet Draft. */ if (tcp->tcp_snd_ts_ok && TSTMP_GEQ(tcpopt.tcp_opt_ts_val, tcp->tcp_ts_recent) && SEQ_LEQ(seg_seq, tcp->tcp_rack)) { tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val; tcp->tcp_last_rcv_lbolt = prom_gettime(); } if (seg_seq != tcp->tcp_rnxt || tcp->tcp_reass_head) { /* * FIN in an out of order segment. We record this in * tcp_valid_bits and the seq num of FIN in tcp_ofo_fin_seq. * Clear the FIN so that any check on FIN flag will fail. * Remember that FIN also counts in the sequence number * space. So we need to ack out of order FIN only segments. */ if (flags & TH_FIN) { tcp->tcp_valid_bits |= TCP_OFO_FIN_VALID; tcp->tcp_ofo_fin_seq = seg_seq + seg_len; flags &= ~TH_FIN; flags |= TH_ACK_NEEDED; } if (seg_len > 0) { /* Fill in the SACK blk list. */ if (tcp->tcp_snd_sack_ok) { assert(tcp->tcp_sack_info != NULL); tcp_sack_insert(tcp->tcp_sack_list, seg_seq, seg_seq + seg_len, &(tcp->tcp_num_sack_blk)); } /* * Attempt reassembly and see if we have something * ready to go. */ mp = tcp_reass(tcp, mp, seg_seq); /* Always ack out of order packets */ flags |= TH_ACK_NEEDED | TH_PUSH; if (mp != NULL) { assert((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)INT_MAX); seg_len = mp->b_cont ? msgdsize(mp) : (int)(mp->b_wptr - mp->b_rptr); seg_seq = tcp->tcp_rnxt; /* * A gap is filled and the seq num and len * of the gap match that of a previously * received FIN, put the FIN flag back in. */ if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) && seg_seq + seg_len == tcp->tcp_ofo_fin_seq) { flags |= TH_FIN; tcp->tcp_valid_bits &= ~TCP_OFO_FIN_VALID; } } else { /* * Keep going even with NULL mp. * There may be a useful ACK or something else * we don't want to miss. * * But TCP should not perform fast retransmit * because of the ack number. TCP uses * seg_len == 0 to determine if it is a pure * ACK. And this is not a pure ACK. */ seg_len = 0; ofo_seg = B_TRUE; } } } else if (seg_len > 0) { BUMP_MIB(tcp_mib.tcpInDataInorderSegs); UPDATE_MIB(tcp_mib.tcpInDataInorderBytes, seg_len); /* * If an out of order FIN was received before, and the seq * num and len of the new segment match that of the FIN, * put the FIN flag back in. */ if ((tcp->tcp_valid_bits & TCP_OFO_FIN_VALID) && seg_seq + seg_len == tcp->tcp_ofo_fin_seq) { flags |= TH_FIN; tcp->tcp_valid_bits &= ~TCP_OFO_FIN_VALID; } } if ((flags & (TH_RST | TH_SYN | TH_URG | TH_ACK)) != TH_ACK) { if (flags & TH_RST) { freemsg(mp); switch (tcp->tcp_state) { case TCPS_SYN_RCVD: (void) tcp_clean_death(sock_id, tcp, ECONNREFUSED); break; case TCPS_ESTABLISHED: case TCPS_FIN_WAIT_1: case TCPS_FIN_WAIT_2: case TCPS_CLOSE_WAIT: (void) tcp_clean_death(sock_id, tcp, ECONNRESET); break; case TCPS_CLOSING: case TCPS_LAST_ACK: (void) tcp_clean_death(sock_id, tcp, 0); break; default: assert(tcp->tcp_state != TCPS_TIME_WAIT); (void) tcp_clean_death(sock_id, tcp, ENXIO); break; } return; } if (flags & TH_SYN) { /* * See RFC 793, Page 71 * * The seq number must be in the window as it should * be "fixed" above. If it is outside window, it should * be already rejected. Note that we allow seg_seq to be * rnxt + rwnd because we want to accept 0 window probe. */ assert(SEQ_GEQ(seg_seq, tcp->tcp_rnxt) && SEQ_LEQ(seg_seq, tcp->tcp_rnxt + tcp->tcp_rwnd)); freemsg(mp); /* * If the ACK flag is not set, just use our snxt as the * seq number of the RST segment. */ if (!(flags & TH_ACK)) { seg_ack = tcp->tcp_snxt; } tcp_xmit_ctl("TH_SYN", tcp, NULL, seg_ack, seg_seq + 1, TH_RST|TH_ACK, 0, sock_id); assert(tcp->tcp_state != TCPS_TIME_WAIT); (void) tcp_clean_death(sock_id, tcp, ECONNRESET); return; } process_ack: if (!(flags & TH_ACK)) { #ifdef DEBUG printf("No ack in segment, dropped it, seq:%x\n", seg_seq); #endif freemsg(mp); goto xmit_check; } } bytes_acked = (int)(seg_ack - tcp->tcp_suna); if (tcp->tcp_state == TCPS_SYN_RCVD) { tcp_t *listener = tcp->tcp_listener; #ifdef DEBUG printf("Done with eager 3-way handshake\n"); #endif /* * NOTE: RFC 793 pg. 72 says this should be 'bytes_acked < 0' * but that would mean we have an ack that ignored our SYN. */ if (bytes_acked < 1 || SEQ_GT(seg_ack, tcp->tcp_snxt)) { freemsg(mp); tcp_xmit_ctl("TCPS_SYN_RCVD-bad_ack", tcp, NULL, seg_ack, 0, TH_RST, 0, sock_id); return; } /* * if the conn_req_q is full defer processing * until space is availabe after accept() * processing */ if (listener->tcp_conn_req_cnt_q < listener->tcp_conn_req_max) { tcp_t *tail; listener->tcp_conn_req_cnt_q0--; listener->tcp_conn_req_cnt_q++; /* Move from SYN_RCVD to ESTABLISHED list */ tcp->tcp_eager_next_q0->tcp_eager_prev_q0 = tcp->tcp_eager_prev_q0; tcp->tcp_eager_prev_q0->tcp_eager_next_q0 = tcp->tcp_eager_next_q0; tcp->tcp_eager_prev_q0 = NULL; tcp->tcp_eager_next_q0 = NULL; /* * Insert at end of the queue because sockfs * sends down T_CONN_RES in chronological * order. Leaving the older conn indications * at front of the queue helps reducing search * time. */ tail = listener->tcp_eager_last_q; if (tail != NULL) { tail->tcp_eager_next_q = tcp; } else { listener->tcp_eager_next_q = tcp; } listener->tcp_eager_last_q = tcp; tcp->tcp_eager_next_q = NULL; } else { /* * Defer connection on q0 and set deferred * connection bit true */ tcp->tcp_conn_def_q0 = B_TRUE; /* take tcp out of q0 ... */ tcp->tcp_eager_prev_q0->tcp_eager_next_q0 = tcp->tcp_eager_next_q0; tcp->tcp_eager_next_q0->tcp_eager_prev_q0 = tcp->tcp_eager_prev_q0; /* ... and place it at the end of q0 */ tcp->tcp_eager_prev_q0 = listener->tcp_eager_prev_q0; tcp->tcp_eager_next_q0 = listener; listener->tcp_eager_prev_q0->tcp_eager_next_q0 = tcp; listener->tcp_eager_prev_q0 = tcp; } tcp->tcp_suna = tcp->tcp_iss + 1; /* One for the SYN */ bytes_acked--; /* * If SYN was retransmitted, need to reset all * retransmission info as this segment will be * treated as a dup ACK. */ if (tcp->tcp_rexmit) { tcp->tcp_rexmit = B_FALSE; tcp->tcp_rexmit_nxt = tcp->tcp_snxt; tcp->tcp_rexmit_max = tcp->tcp_snxt; tcp->tcp_snd_burst = TCP_CWND_NORMAL; tcp->tcp_ms_we_have_waited = 0; tcp->tcp_cwnd = mss; } /* * We set the send window to zero here. * This is needed if there is data to be * processed already on the queue. * Later (at swnd_update label), the * "new_swnd > tcp_swnd" condition is satisfied * the XMIT_NEEDED flag is set in the current * (SYN_RCVD) state. This ensures tcp_wput_data() is * called if there is already data on queue in * this state. */ tcp->tcp_swnd = 0; if (new_swnd > tcp->tcp_max_swnd) tcp->tcp_max_swnd = new_swnd; tcp->tcp_swl1 = seg_seq; tcp->tcp_swl2 = seg_ack; tcp->tcp_state = TCPS_ESTABLISHED; tcp->tcp_valid_bits &= ~TCP_ISS_VALID; } /* This code follows 4.4BSD-Lite2 mostly. */ if (bytes_acked < 0) goto est; /* * If TCP is ECN capable and the congestion experience bit is * set, reduce tcp_cwnd and tcp_ssthresh. But this should only be * done once per window (or more loosely, per RTT). */ if (tcp->tcp_cwr && SEQ_GT(seg_ack, tcp->tcp_cwr_snd_max)) tcp->tcp_cwr = B_FALSE; if (tcp->tcp_ecn_ok && (flags & TH_ECE)) { if (!tcp->tcp_cwr) { npkt = (MIN(tcp->tcp_cwnd, tcp->tcp_swnd) >> 1) / mss; tcp->tcp_cwnd_ssthresh = MAX(npkt, 2) * mss; tcp->tcp_cwnd = npkt * mss; /* * If the cwnd is 0, use the timer to clock out * new segments. This is required by the ECN spec. */ if (npkt == 0) { TCP_TIMER_RESTART(tcp, tcp->tcp_rto); /* * This makes sure that when the ACK comes * back, we will increase tcp_cwnd by 1 MSS. */ tcp->tcp_cwnd_cnt = 0; } tcp->tcp_cwr = B_TRUE; /* * This marks the end of the current window of in * flight data. That is why we don't use * tcp_suna + tcp_swnd. Only data in flight can * provide ECN info. */ tcp->tcp_cwr_snd_max = tcp->tcp_snxt; tcp->tcp_ecn_cwr_sent = B_FALSE; } } mp1 = tcp->tcp_xmit_head; if (bytes_acked == 0) { if (!ofo_seg && seg_len == 0 && new_swnd == tcp->tcp_swnd) { int dupack_cnt; BUMP_MIB(tcp_mib.tcpInDupAck); /* * Fast retransmit. When we have seen exactly three * identical ACKs while we have unacked data * outstanding we take it as a hint that our peer * dropped something. * * If TCP is retransmitting, don't do fast retransmit. */ if (mp1 != NULL && tcp->tcp_suna != tcp->tcp_snxt && ! tcp->tcp_rexmit) { /* Do Limited Transmit */ if ((dupack_cnt = ++tcp->tcp_dupack_cnt) < tcp_dupack_fast_retransmit) { /* * RFC 3042 * * What we need to do is temporarily * increase tcp_cwnd so that new * data can be sent if it is allowed * by the receive window (tcp_rwnd). * tcp_wput_data() will take care of * the rest. * * If the connection is SACK capable, * only do limited xmit when there * is SACK info. * * Note how tcp_cwnd is incremented. * The first dup ACK will increase * it by 1 MSS. The second dup ACK * will increase it by 2 MSS. This * means that only 1 new segment will * be sent for each dup ACK. */ if (tcp->tcp_unsent > 0 && (!tcp->tcp_snd_sack_ok || (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL))) { tcp->tcp_cwnd += mss << (tcp->tcp_dupack_cnt - 1); flags |= TH_LIMIT_XMIT; } } else if (dupack_cnt == tcp_dupack_fast_retransmit) { BUMP_MIB(tcp_mib.tcpOutFastRetrans); /* * If we have reduced tcp_ssthresh * because of ECN, do not reduce it again * unless it is already one window of data * away. After one window of data, tcp_cwr * should then be cleared. Note that * for non ECN capable connection, tcp_cwr * should always be false. * * Adjust cwnd since the duplicate * ack indicates that a packet was * dropped (due to congestion.) */ if (!tcp->tcp_cwr) { npkt = (MIN(tcp->tcp_cwnd, tcp->tcp_swnd) >> 1) / mss; if (npkt < 2) npkt = 2; tcp->tcp_cwnd_ssthresh = npkt * mss; tcp->tcp_cwnd = (npkt + tcp->tcp_dupack_cnt) * mss; } if (tcp->tcp_ecn_ok) { tcp->tcp_cwr = B_TRUE; tcp->tcp_cwr_snd_max = tcp->tcp_snxt; tcp->tcp_ecn_cwr_sent = B_FALSE; } /* * We do Hoe's algorithm. Refer to her * paper "Improving the Start-up Behavior * of a Congestion Control Scheme for TCP," * appeared in SIGCOMM'96. * * Save highest seq no we have sent so far. * Be careful about the invisible FIN byte. */ if ((tcp->tcp_valid_bits & TCP_FSS_VALID) && (tcp->tcp_unsent == 0)) { tcp->tcp_rexmit_max = tcp->tcp_fss; } else { tcp->tcp_rexmit_max = tcp->tcp_snxt; } /* * Do not allow bursty traffic during. * fast recovery. Refer to Fall and Floyd's * paper "Simulation-based Comparisons of * Tahoe, Reno and SACK TCP" (in CCR ??) * This is a best current practise. */ tcp->tcp_snd_burst = TCP_CWND_SS; /* * For SACK: * Calculate tcp_pipe, which is the * estimated number of bytes in * network. * * tcp_fack is the highest sack'ed seq num * TCP has received. * * tcp_pipe is explained in the above quoted * Fall and Floyd's paper. tcp_fack is * explained in Mathis and Mahdavi's * "Forward Acknowledgment: Refining TCP * Congestion Control" in SIGCOMM '96. */ if (tcp->tcp_snd_sack_ok) { assert(tcp->tcp_sack_info != NULL); if (tcp->tcp_notsack_list != NULL) { tcp->tcp_pipe = tcp->tcp_snxt - tcp->tcp_fack; tcp->tcp_sack_snxt = seg_ack; flags |= TH_NEED_SACK_REXMIT; } else { /* * Always initialize tcp_pipe * even though we don't have * any SACK info. If later * we get SACK info and * tcp_pipe is not initialized, * funny things will happen. */ tcp->tcp_pipe = tcp->tcp_cwnd_ssthresh; } } else { flags |= TH_REXMIT_NEEDED; } /* tcp_snd_sack_ok */ } else { /* * Here we perform congestion * avoidance, but NOT slow start. * This is known as the Fast * Recovery Algorithm. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { flags |= TH_NEED_SACK_REXMIT; tcp->tcp_pipe -= mss; if (tcp->tcp_pipe < 0) tcp->tcp_pipe = 0; } else { /* * We know that one more packet has * left the pipe thus we can update * cwnd. */ cwnd = tcp->tcp_cwnd + mss; if (cwnd > tcp->tcp_cwnd_max) cwnd = tcp->tcp_cwnd_max; tcp->tcp_cwnd = cwnd; flags |= TH_XMIT_NEEDED; } } } } else if (tcp->tcp_zero_win_probe) { /* * If the window has opened, need to arrange * to send additional data. */ if (new_swnd != 0) { /* tcp_suna != tcp_snxt */ /* Packet contains a window update */ BUMP_MIB(tcp_mib.tcpInWinUpdate); tcp->tcp_zero_win_probe = 0; tcp->tcp_timer_backoff = 0; tcp->tcp_ms_we_have_waited = 0; /* * Transmit starting with tcp_suna since * the one byte probe is not ack'ed. * If TCP has sent more than one identical * probe, tcp_rexmit will be set. That means * tcp_ss_rexmit() will send out the one * byte along with new data. Otherwise, * fake the retransmission. */ flags |= TH_XMIT_NEEDED; if (!tcp->tcp_rexmit) { tcp->tcp_rexmit = B_TRUE; tcp->tcp_dupack_cnt = 0; tcp->tcp_rexmit_nxt = tcp->tcp_suna; tcp->tcp_rexmit_max = tcp->tcp_suna + 1; } } } goto swnd_update; } /* * Check for "acceptability" of ACK value per RFC 793, pages 72 - 73. * If the ACK value acks something that we have not yet sent, it might * be an old duplicate segment. Send an ACK to re-synchronize the * other side. * Note: reset in response to unacceptable ACK in SYN_RECEIVE * state is handled above, so we can always just drop the segment and * send an ACK here. * * Should we send ACKs in response to ACK only segments? */ if (SEQ_GT(seg_ack, tcp->tcp_snxt)) { BUMP_MIB(tcp_mib.tcpInAckUnsent); /* drop the received segment */ freemsg(mp); /* Send back an ACK. */ mp = tcp_ack_mp(tcp); if (mp == NULL) { return; } BUMP_MIB(tcp_mib.tcpOutAck); (void) ipv4_tcp_output(sock_id, mp); freeb(mp); return; } /* * TCP gets a new ACK, update the notsack'ed list to delete those * blocks that are covered by this ACK. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { tcp_notsack_remove(&(tcp->tcp_notsack_list), seg_ack, &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list)); } /* * If we got an ACK after fast retransmit, check to see * if it is a partial ACK. If it is not and the congestion * window was inflated to account for the other side's * cached packets, retract it. If it is, do Hoe's algorithm. */ if (tcp->tcp_dupack_cnt >= tcp_dupack_fast_retransmit) { assert(tcp->tcp_rexmit == B_FALSE); if (SEQ_GEQ(seg_ack, tcp->tcp_rexmit_max)) { tcp->tcp_dupack_cnt = 0; /* * Restore the orig tcp_cwnd_ssthresh after * fast retransmit phase. */ if (tcp->tcp_cwnd > tcp->tcp_cwnd_ssthresh) { tcp->tcp_cwnd = tcp->tcp_cwnd_ssthresh; } tcp->tcp_rexmit_max = seg_ack; tcp->tcp_cwnd_cnt = 0; tcp->tcp_snd_burst = TCP_CWND_NORMAL; /* * Remove all notsack info to avoid confusion with * the next fast retrasnmit/recovery phase. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list); } } else { if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { flags |= TH_NEED_SACK_REXMIT; tcp->tcp_pipe -= mss; if (tcp->tcp_pipe < 0) tcp->tcp_pipe = 0; } else { /* * Hoe's algorithm: * * Retransmit the unack'ed segment and * restart fast recovery. Note that we * need to scale back tcp_cwnd to the * original value when we started fast * recovery. This is to prevent overly * aggressive behaviour in sending new * segments. */ tcp->tcp_cwnd = tcp->tcp_cwnd_ssthresh + tcp_dupack_fast_retransmit * mss; tcp->tcp_cwnd_cnt = tcp->tcp_cwnd; BUMP_MIB(tcp_mib.tcpOutFastRetrans); flags |= TH_REXMIT_NEEDED; } } } else { tcp->tcp_dupack_cnt = 0; if (tcp->tcp_rexmit) { /* * TCP is retranmitting. If the ACK ack's all * outstanding data, update tcp_rexmit_max and * tcp_rexmit_nxt. Otherwise, update tcp_rexmit_nxt * to the correct value. * * Note that SEQ_LEQ() is used. This is to avoid * unnecessary fast retransmit caused by dup ACKs * received when TCP does slow start retransmission * after a time out. During this phase, TCP may * send out segments which are already received. * This causes dup ACKs to be sent back. */ if (SEQ_LEQ(seg_ack, tcp->tcp_rexmit_max)) { if (SEQ_GT(seg_ack, tcp->tcp_rexmit_nxt)) { tcp->tcp_rexmit_nxt = seg_ack; } if (seg_ack != tcp->tcp_rexmit_max) { flags |= TH_XMIT_NEEDED; } } else { tcp->tcp_rexmit = B_FALSE; tcp->tcp_rexmit_nxt = tcp->tcp_snxt; tcp->tcp_snd_burst = TCP_CWND_NORMAL; } tcp->tcp_ms_we_have_waited = 0; } } BUMP_MIB(tcp_mib.tcpInAckSegs); UPDATE_MIB(tcp_mib.tcpInAckBytes, bytes_acked); tcp->tcp_suna = seg_ack; if (tcp->tcp_zero_win_probe != 0) { tcp->tcp_zero_win_probe = 0; tcp->tcp_timer_backoff = 0; } /* * If tcp_xmit_head is NULL, then it must be the FIN being ack'ed. * Note that it cannot be the SYN being ack'ed. The code flow * will not reach here. */ if (mp1 == NULL) { goto fin_acked; } /* * Update the congestion window. * * If TCP is not ECN capable or TCP is ECN capable but the * congestion experience bit is not set, increase the tcp_cwnd as * usual. */ if (!tcp->tcp_ecn_ok || !(flags & TH_ECE)) { cwnd = tcp->tcp_cwnd; add = mss; if (cwnd >= tcp->tcp_cwnd_ssthresh) { /* * This is to prevent an increase of less than 1 MSS of * tcp_cwnd. With partial increase, tcp_wput_data() * may send out tinygrams in order to preserve mblk * boundaries. * * By initializing tcp_cwnd_cnt to new tcp_cwnd and * decrementing it by 1 MSS for every ACKs, tcp_cwnd is * increased by 1 MSS for every RTTs. */ if (tcp->tcp_cwnd_cnt <= 0) { tcp->tcp_cwnd_cnt = cwnd + add; } else { tcp->tcp_cwnd_cnt -= add; add = 0; } } tcp->tcp_cwnd = MIN(cwnd + add, tcp->tcp_cwnd_max); } /* Can we update the RTT estimates? */ if (tcp->tcp_snd_ts_ok) { /* Ignore zero timestamp echo-reply. */ if (tcpopt.tcp_opt_ts_ecr != 0) { tcp_set_rto(tcp, (int32_t)(prom_gettime() - tcpopt.tcp_opt_ts_ecr)); } /* If needed, restart the timer. */ if (tcp->tcp_set_timer == 1) { TCP_TIMER_RESTART(tcp, tcp->tcp_rto); tcp->tcp_set_timer = 0; } /* * Update tcp_csuna in case the other side stops sending * us timestamps. */ tcp->tcp_csuna = tcp->tcp_snxt; } else if (SEQ_GT(seg_ack, tcp->tcp_csuna)) { /* * An ACK sequence we haven't seen before, so get the RTT * and update the RTO. * Note. use uintptr_t to suppress the gcc warning. */ tcp_set_rto(tcp, (int32_t)(prom_gettime() - (uint32_t)(uintptr_t)mp1->b_prev)); /* Remeber the last sequence to be ACKed */ tcp->tcp_csuna = seg_ack; if (tcp->tcp_set_timer == 1) { TCP_TIMER_RESTART(tcp, tcp->tcp_rto); tcp->tcp_set_timer = 0; } } else { BUMP_MIB(tcp_mib.tcpRttNoUpdate); } /* Eat acknowledged bytes off the xmit queue. */ for (;;) { mblk_t *mp2; uchar_t *wptr; wptr = mp1->b_wptr; assert((uintptr_t)(wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX); bytes_acked -= (int)(wptr - mp1->b_rptr); if (bytes_acked < 0) { mp1->b_rptr = wptr + bytes_acked; break; } mp1->b_prev = NULL; mp2 = mp1; mp1 = mp1->b_cont; freeb(mp2); if (bytes_acked == 0) { if (mp1 == NULL) { /* Everything is ack'ed, clear the tail. */ tcp->tcp_xmit_tail = NULL; goto pre_swnd_update; } if (mp2 != tcp->tcp_xmit_tail) break; tcp->tcp_xmit_tail = mp1; assert((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX); tcp->tcp_xmit_tail_unsent = (int)(mp1->b_wptr - mp1->b_rptr); break; } if (mp1 == NULL) { /* * More was acked but there is nothing more * outstanding. This means that the FIN was * just acked or that we're talking to a clown. */ fin_acked: assert(tcp->tcp_fin_sent); tcp->tcp_xmit_tail = NULL; if (tcp->tcp_fin_sent) { tcp->tcp_fin_acked = B_TRUE; } else { /* * We should never got here because * we have already checked that the * number of bytes ack'ed should be * smaller than or equal to what we * have sent so far (it is the * acceptability check of the ACK). * We can only get here if the send * queue is corrupted. * * Terminate the connection and * panic the system. It is better * for us to panic instead of * continuing to avoid other disaster. */ tcp_xmit_ctl(NULL, tcp, NULL, tcp->tcp_snxt, tcp->tcp_rnxt, TH_RST|TH_ACK, 0, sock_id); printf("Memory corruption " "detected for connection %s.\n", tcp_display(tcp, NULL, DISP_ADDR_AND_PORT)); /* We should never get here... */ prom_panic("tcp_rput_data"); return; } goto pre_swnd_update; } assert(mp2 != tcp->tcp_xmit_tail); } if (tcp->tcp_unsent) { flags |= TH_XMIT_NEEDED; } pre_swnd_update: tcp->tcp_xmit_head = mp1; swnd_update: /* * The following check is different from most other implementations. * For bi-directional transfer, when segments are dropped, the * "normal" check will not accept a window update in those * retransmitted segemnts. Failing to do that, TCP may send out * segments which are outside receiver's window. As TCP accepts * the ack in those retransmitted segments, if the window update in * the same segment is not accepted, TCP will incorrectly calculates * that it can send more segments. This can create a deadlock * with the receiver if its window becomes zero. */ if (SEQ_LT(tcp->tcp_swl2, seg_ack) || SEQ_LT(tcp->tcp_swl1, seg_seq) || (tcp->tcp_swl1 == seg_seq && new_swnd > tcp->tcp_swnd)) { /* * The criteria for update is: * * 1. the segment acknowledges some data. Or * 2. the segment is new, i.e. it has a higher seq num. Or * 3. the segment is not old and the advertised window is * larger than the previous advertised window. */ if (tcp->tcp_unsent && new_swnd > tcp->tcp_swnd) flags |= TH_XMIT_NEEDED; tcp->tcp_swnd = new_swnd; if (new_swnd > tcp->tcp_max_swnd) tcp->tcp_max_swnd = new_swnd; tcp->tcp_swl1 = seg_seq; tcp->tcp_swl2 = seg_ack; } est: if (tcp->tcp_state > TCPS_ESTABLISHED) { switch (tcp->tcp_state) { case TCPS_FIN_WAIT_1: if (tcp->tcp_fin_acked) { tcp->tcp_state = TCPS_FIN_WAIT_2; /* * We implement the non-standard BSD/SunOS * FIN_WAIT_2 flushing algorithm. * If there is no user attached to this * TCP endpoint, then this TCP struct * could hang around forever in FIN_WAIT_2 * state if the peer forgets to send us * a FIN. To prevent this, we wait only * 2*MSL (a convenient time value) for * the FIN to arrive. If it doesn't show up, * we flush the TCP endpoint. This algorithm, * though a violation of RFC-793, has worked * for over 10 years in BSD systems. * Note: SunOS 4.x waits 675 seconds before * flushing the FIN_WAIT_2 connection. */ TCP_TIMER_RESTART(tcp, tcp_fin_wait_2_flush_interval); } break; case TCPS_FIN_WAIT_2: break; /* Shutdown hook? */ case TCPS_LAST_ACK: freemsg(mp); if (tcp->tcp_fin_acked) { (void) tcp_clean_death(sock_id, tcp, 0); return; } goto xmit_check; case TCPS_CLOSING: if (tcp->tcp_fin_acked) { tcp->tcp_state = TCPS_TIME_WAIT; tcp_time_wait_append(tcp); TCP_TIMER_RESTART(tcp, tcp_time_wait_interval); } /*FALLTHRU*/ case TCPS_CLOSE_WAIT: freemsg(mp); goto xmit_check; default: assert(tcp->tcp_state != TCPS_TIME_WAIT); break; } } if (flags & TH_FIN) { /* Make sure we ack the fin */ flags |= TH_ACK_NEEDED; if (!tcp->tcp_fin_rcvd) { tcp->tcp_fin_rcvd = B_TRUE; tcp->tcp_rnxt++; U32_TO_ABE32(tcp->tcp_rnxt, tcp->tcp_tcph->th_ack); switch (tcp->tcp_state) { case TCPS_SYN_RCVD: case TCPS_ESTABLISHED: tcp->tcp_state = TCPS_CLOSE_WAIT; /* Keepalive? */ break; case TCPS_FIN_WAIT_1: if (!tcp->tcp_fin_acked) { tcp->tcp_state = TCPS_CLOSING; break; } /* FALLTHRU */ case TCPS_FIN_WAIT_2: tcp->tcp_state = TCPS_TIME_WAIT; tcp_time_wait_append(tcp); TCP_TIMER_RESTART(tcp, tcp_time_wait_interval); if (seg_len) { /* * implies data piggybacked on FIN. * break to handle data. */ break; } freemsg(mp); goto ack_check; } } } if (mp == NULL) goto xmit_check; if (seg_len == 0) { freemsg(mp); goto xmit_check; } if (mp->b_rptr == mp->b_wptr) { /* * The header has been consumed, so we remove the * zero-length mblk here. */ mp1 = mp; mp = mp->b_cont; freeb(mp1); } /* * ACK every other segments, unless the input queue is empty * as we don't have a timer available. */ if (++tcp->tcp_rack_cnt == 2 || sockets[sock_id].inq == NULL) { flags |= TH_ACK_NEEDED; tcp->tcp_rack_cnt = 0; } tcp->tcp_rnxt += seg_len; U32_TO_ABE32(tcp->tcp_rnxt, tcp->tcp_tcph->th_ack); /* Update SACK list */ if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) { tcp_sack_remove(tcp->tcp_sack_list, tcp->tcp_rnxt, &(tcp->tcp_num_sack_blk)); } if (tcp->tcp_listener) { /* * Side queue inbound data until the accept happens. * tcp_accept/tcp_rput drains this when the accept happens. */ tcp_rcv_enqueue(tcp, mp, seg_len); } else { /* Just queue the data until the app calls read. */ tcp_rcv_enqueue(tcp, mp, seg_len); /* * Make sure the timer is running if we have data waiting * for a push bit. This provides resiliency against * implementations that do not correctly generate push bits. */ if (tcp->tcp_rcv_list != NULL) flags |= TH_TIMER_NEEDED; } xmit_check: /* Is there anything left to do? */ if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_ACK_NEEDED| TH_NEED_SACK_REXMIT|TH_LIMIT_XMIT|TH_TIMER_NEEDED)) == 0) return; /* Any transmit work to do and a non-zero window? */ if ((flags & (TH_REXMIT_NEEDED|TH_XMIT_NEEDED|TH_NEED_SACK_REXMIT| TH_LIMIT_XMIT)) && tcp->tcp_swnd != 0) { if (flags & TH_REXMIT_NEEDED) { uint32_t snd_size = tcp->tcp_snxt - tcp->tcp_suna; if (snd_size > mss) snd_size = mss; if (snd_size > tcp->tcp_swnd) snd_size = tcp->tcp_swnd; mp1 = tcp_xmit_mp(tcp, tcp->tcp_xmit_head, snd_size, NULL, NULL, tcp->tcp_suna, B_TRUE, &snd_size, B_TRUE); if (mp1 != NULL) { /* use uintptr_t to suppress the gcc warning */ tcp->tcp_xmit_head->b_prev = (mblk_t *)(uintptr_t)prom_gettime(); tcp->tcp_csuna = tcp->tcp_snxt; BUMP_MIB(tcp_mib.tcpRetransSegs); UPDATE_MIB(tcp_mib.tcpRetransBytes, snd_size); (void) ipv4_tcp_output(sock_id, mp1); freeb(mp1); } } if (flags & TH_NEED_SACK_REXMIT) { if (tcp_sack_rxmit(tcp, sock_id) != 0) { flags |= TH_XMIT_NEEDED; } } /* * For TH_LIMIT_XMIT, tcp_wput_data() is called to send * out new segment. Note that tcp_rexmit should not be * set, otherwise TH_LIMIT_XMIT should not be set. */ if (flags & (TH_XMIT_NEEDED|TH_LIMIT_XMIT)) { if (!tcp->tcp_rexmit) { tcp_wput_data(tcp, NULL, sock_id); } else { tcp_ss_rexmit(tcp, sock_id); } /* * The TCP could be closed in tcp_state_wait via * tcp_wput_data (tcp_ss_rexmit could call * tcp_wput_data as well). */ if (sockets[sock_id].pcb == NULL) return; } /* * Adjust tcp_cwnd back to normal value after sending * new data segments. */ if (flags & TH_LIMIT_XMIT) { tcp->tcp_cwnd -= mss << (tcp->tcp_dupack_cnt - 1); } /* Anything more to do? */ if ((flags & (TH_ACK_NEEDED|TH_TIMER_NEEDED)) == 0) return; } ack_check: if (flags & TH_ACK_NEEDED) { /* * Time to send an ack for some reason. */ if ((mp1 = tcp_ack_mp(tcp)) != NULL) { TCP_DUMP_PACKET("tcp_rput_data: ack mp", mp1); (void) ipv4_tcp_output(sock_id, mp1); BUMP_MIB(tcp_mib.tcpOutAck); freeb(mp1); } } } /* * tcp_ss_rexmit() is called in tcp_rput_data() to do slow start * retransmission after a timeout. * * To limit the number of duplicate segments, we limit the number of segment * to be sent in one time to tcp_snd_burst, the burst variable. */ static void tcp_ss_rexmit(tcp_t *tcp, int sock_id) { uint32_t snxt; uint32_t smax; int32_t win; int32_t mss; int32_t off; int32_t burst = tcp->tcp_snd_burst; mblk_t *snxt_mp; /* * Note that tcp_rexmit can be set even though TCP has retransmitted * all unack'ed segments. */ if (SEQ_LT(tcp->tcp_rexmit_nxt, tcp->tcp_rexmit_max)) { smax = tcp->tcp_rexmit_max; snxt = tcp->tcp_rexmit_nxt; if (SEQ_LT(snxt, tcp->tcp_suna)) { snxt = tcp->tcp_suna; } win = MIN(tcp->tcp_cwnd, tcp->tcp_swnd); win -= snxt - tcp->tcp_suna; mss = tcp->tcp_mss; snxt_mp = tcp_get_seg_mp(tcp, snxt, &off); while (SEQ_LT(snxt, smax) && (win > 0) && (burst > 0) && (snxt_mp != NULL)) { mblk_t *xmit_mp; mblk_t *old_snxt_mp = snxt_mp; uint32_t cnt = mss; if (win < cnt) { cnt = win; } if (SEQ_GT(snxt + cnt, smax)) { cnt = smax - snxt; } xmit_mp = tcp_xmit_mp(tcp, snxt_mp, cnt, &off, &snxt_mp, snxt, B_TRUE, &cnt, B_TRUE); if (xmit_mp == NULL) return; (void) ipv4_tcp_output(sock_id, xmit_mp); freeb(xmit_mp); snxt += cnt; win -= cnt; /* * Update the send timestamp to avoid false * retransmission. * Note. use uintptr_t to suppress the gcc warning. */ old_snxt_mp->b_prev = (mblk_t *)(uintptr_t)prom_gettime(); BUMP_MIB(tcp_mib.tcpRetransSegs); UPDATE_MIB(tcp_mib.tcpRetransBytes, cnt); tcp->tcp_rexmit_nxt = snxt; burst--; } /* * If we have transmitted all we have at the time * we started the retranmission, we can leave * the rest of the job to tcp_wput_data(). But we * need to check the send window first. If the * win is not 0, go on with tcp_wput_data(). */ if (SEQ_LT(snxt, smax) || win == 0) { return; } } /* Only call tcp_wput_data() if there is data to be sent. */ if (tcp->tcp_unsent) { tcp_wput_data(tcp, NULL, sock_id); } } /* * tcp_timer is the timer service routine. It handles all timer events for * a tcp instance except keepalives. It figures out from the state of the * tcp instance what kind of action needs to be done at the time it is called. */ static void tcp_timer(tcp_t *tcp, int sock_id) { mblk_t *mp; uint32_t first_threshold; uint32_t second_threshold; uint32_t ms; uint32_t mss; first_threshold = tcp->tcp_first_timer_threshold; second_threshold = tcp->tcp_second_timer_threshold; switch (tcp->tcp_state) { case TCPS_IDLE: case TCPS_BOUND: case TCPS_LISTEN: return; case TCPS_SYN_RCVD: case TCPS_SYN_SENT: first_threshold = tcp->tcp_first_ctimer_threshold; second_threshold = tcp->tcp_second_ctimer_threshold; break; case TCPS_ESTABLISHED: case TCPS_FIN_WAIT_1: case TCPS_CLOSING: case TCPS_CLOSE_WAIT: case TCPS_LAST_ACK: /* If we have data to rexmit */ if (tcp->tcp_suna != tcp->tcp_snxt) { int32_t time_to_wait; BUMP_MIB(tcp_mib.tcpTimRetrans); if (tcp->tcp_xmit_head == NULL) break; /* use uintptr_t to suppress the gcc warning */ time_to_wait = (int32_t)(prom_gettime() - (uint32_t)(uintptr_t)tcp->tcp_xmit_head->b_prev); time_to_wait = tcp->tcp_rto - time_to_wait; if (time_to_wait > 0) { /* * Timer fired too early, so restart it. */ TCP_TIMER_RESTART(tcp, time_to_wait); return; } /* * When we probe zero windows, we force the swnd open. * If our peer acks with a closed window swnd will be * set to zero by tcp_rput(). As long as we are * receiving acks tcp_rput will * reset 'tcp_ms_we_have_waited' so as not to trip the * first and second interval actions. NOTE: the timer * interval is allowed to continue its exponential * backoff. */ if (tcp->tcp_swnd == 0 || tcp->tcp_zero_win_probe) { DEBUG_1("tcp_timer (%d): zero win", sock_id); break; } else { /* * After retransmission, we need to do * slow start. Set the ssthresh to one * half of current effective window and * cwnd to one MSS. Also reset * tcp_cwnd_cnt. * * Note that if tcp_ssthresh is reduced because * of ECN, do not reduce it again unless it is * already one window of data away (tcp_cwr * should then be cleared) or this is a * timeout for a retransmitted segment. */ uint32_t npkt; if (!tcp->tcp_cwr || tcp->tcp_rexmit) { npkt = (MIN((tcp->tcp_timer_backoff ? tcp->tcp_cwnd_ssthresh : tcp->tcp_cwnd), tcp->tcp_swnd) >> 1) / tcp->tcp_mss; if (npkt < 2) npkt = 2; tcp->tcp_cwnd_ssthresh = npkt * tcp->tcp_mss; } tcp->tcp_cwnd = tcp->tcp_mss; tcp->tcp_cwnd_cnt = 0; if (tcp->tcp_ecn_ok) { tcp->tcp_cwr = B_TRUE; tcp->tcp_cwr_snd_max = tcp->tcp_snxt; tcp->tcp_ecn_cwr_sent = B_FALSE; } } break; } /* * We have something to send yet we cannot send. The * reason can be: * * 1. Zero send window: we need to do zero window probe. * 2. Zero cwnd: because of ECN, we need to "clock out * segments. * 3. SWS avoidance: receiver may have shrunk window, * reset our knowledge. * * Note that condition 2 can happen with either 1 or * 3. But 1 and 3 are exclusive. */ if (tcp->tcp_unsent != 0) { if (tcp->tcp_cwnd == 0) { /* * Set tcp_cwnd to 1 MSS so that a * new segment can be sent out. We * are "clocking out" new data when * the network is really congested. */ assert(tcp->tcp_ecn_ok); tcp->tcp_cwnd = tcp->tcp_mss; } if (tcp->tcp_swnd == 0) { /* Extend window for zero window probe */ tcp->tcp_swnd++; tcp->tcp_zero_win_probe = B_TRUE; BUMP_MIB(tcp_mib.tcpOutWinProbe); } else { /* * Handle timeout from sender SWS avoidance. * Reset our knowledge of the max send window * since the receiver might have reduced its * receive buffer. Avoid setting tcp_max_swnd * to one since that will essentially disable * the SWS checks. * * Note that since we don't have a SWS * state variable, if the timeout is set * for ECN but not for SWS, this * code will also be executed. This is * fine as tcp_max_swnd is updated * constantly and it will not affect * anything. */ tcp->tcp_max_swnd = MAX(tcp->tcp_swnd, 2); } tcp_wput_data(tcp, NULL, sock_id); return; } /* Is there a FIN that needs to be to re retransmitted? */ if ((tcp->tcp_valid_bits & TCP_FSS_VALID) && !tcp->tcp_fin_acked) break; /* Nothing to do, return without restarting timer. */ return; case TCPS_FIN_WAIT_2: /* * User closed the TCP endpoint and peer ACK'ed our FIN. * We waited some time for for peer's FIN, but it hasn't * arrived. We flush the connection now to avoid * case where the peer has rebooted. */ /* FALLTHRU */ case TCPS_TIME_WAIT: (void) tcp_clean_death(sock_id, tcp, 0); return; default: DEBUG_3("tcp_timer (%d): strange state (%d) %s", sock_id, tcp->tcp_state, tcp_display(tcp, NULL, DISP_PORT_ONLY)); return; } if ((ms = tcp->tcp_ms_we_have_waited) > second_threshold) { /* * For zero window probe, we need to send indefinitely, * unless we have not heard from the other side for some * time... */ if ((tcp->tcp_zero_win_probe == 0) || ((prom_gettime() - tcp->tcp_last_recv_time) > second_threshold)) { BUMP_MIB(tcp_mib.tcpTimRetransDrop); /* * If TCP is in SYN_RCVD state, send back a * RST|ACK as BSD does. Note that tcp_zero_win_probe * should be zero in TCPS_SYN_RCVD state. */ if (tcp->tcp_state == TCPS_SYN_RCVD) { tcp_xmit_ctl("tcp_timer: RST sent on timeout " "in SYN_RCVD", tcp, NULL, tcp->tcp_snxt, tcp->tcp_rnxt, TH_RST | TH_ACK, 0, sock_id); } (void) tcp_clean_death(sock_id, tcp, tcp->tcp_client_errno ? tcp->tcp_client_errno : ETIMEDOUT); return; } else { /* * Set tcp_ms_we_have_waited to second_threshold * so that in next timeout, we will do the above * check (lbolt - tcp_last_recv_time). This is * also to avoid overflow. * * We don't need to decrement tcp_timer_backoff * to avoid overflow because it will be decremented * later if new timeout value is greater than * tcp_rexmit_interval_max. In the case when * tcp_rexmit_interval_max is greater than * second_threshold, it means that we will wait * longer than second_threshold to send the next * window probe. */ tcp->tcp_ms_we_have_waited = second_threshold; } } else if (ms > first_threshold && tcp->tcp_rtt_sa != 0) { /* * We have been retransmitting for too long... The RTT * we calculated is probably incorrect. Reinitialize it. * Need to compensate for 0 tcp_rtt_sa. Reset * tcp_rtt_update so that we won't accidentally cache a * bad value. But only do this if this is not a zero * window probe. */ if (tcp->tcp_zero_win_probe == 0) { tcp->tcp_rtt_sd += (tcp->tcp_rtt_sa >> 3) + (tcp->tcp_rtt_sa >> 5); tcp->tcp_rtt_sa = 0; tcp->tcp_rtt_update = 0; } } tcp->tcp_timer_backoff++; if ((ms = (tcp->tcp_rtt_sa >> 3) + tcp->tcp_rtt_sd + tcp_rexmit_interval_extra + (tcp->tcp_rtt_sa >> 5)) < tcp_rexmit_interval_min) { /* * This means the original RTO is tcp_rexmit_interval_min. * So we will use tcp_rexmit_interval_min as the RTO value * and do the backoff. */ ms = tcp_rexmit_interval_min << tcp->tcp_timer_backoff; } else { ms <<= tcp->tcp_timer_backoff; } if (ms > tcp_rexmit_interval_max) { ms = tcp_rexmit_interval_max; /* * ms is at max, decrement tcp_timer_backoff to avoid * overflow. */ tcp->tcp_timer_backoff--; } tcp->tcp_ms_we_have_waited += ms; if (tcp->tcp_zero_win_probe == 0) { tcp->tcp_rto = ms; } TCP_TIMER_RESTART(tcp, ms); /* * This is after a timeout and tcp_rto is backed off. Set * tcp_set_timer to 1 so that next time RTO is updated, we will * restart the timer with a correct value. */ tcp->tcp_set_timer = 1; mss = tcp->tcp_snxt - tcp->tcp_suna; if (mss > tcp->tcp_mss) mss = tcp->tcp_mss; if (mss > tcp->tcp_swnd && tcp->tcp_swnd != 0) mss = tcp->tcp_swnd; if ((mp = tcp->tcp_xmit_head) != NULL) { /* use uintptr_t to suppress the gcc warning */ mp->b_prev = (mblk_t *)(uintptr_t)prom_gettime(); } mp = tcp_xmit_mp(tcp, mp, mss, NULL, NULL, tcp->tcp_suna, B_TRUE, &mss, B_TRUE); if (mp == NULL) return; tcp->tcp_csuna = tcp->tcp_snxt; BUMP_MIB(tcp_mib.tcpRetransSegs); UPDATE_MIB(tcp_mib.tcpRetransBytes, mss); /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_timer", mp); (void) ipv4_tcp_output(sock_id, mp); freeb(mp); /* * When slow start after retransmission begins, start with * this seq no. tcp_rexmit_max marks the end of special slow * start phase. tcp_snd_burst controls how many segments * can be sent because of an ack. */ tcp->tcp_rexmit_nxt = tcp->tcp_suna; tcp->tcp_snd_burst = TCP_CWND_SS; if ((tcp->tcp_valid_bits & TCP_FSS_VALID) && (tcp->tcp_unsent == 0)) { tcp->tcp_rexmit_max = tcp->tcp_fss; } else { tcp->tcp_rexmit_max = tcp->tcp_snxt; } tcp->tcp_rexmit = B_TRUE; tcp->tcp_dupack_cnt = 0; /* * Remove all rexmit SACK blk to start from fresh. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { TCP_NOTSACK_REMOVE_ALL(tcp->tcp_notsack_list); tcp->tcp_num_notsack_blk = 0; tcp->tcp_cnt_notsack_list = 0; } } /* * The TCP normal data output path. * NOTE: the logic of the fast path is duplicated from this function. */ static void tcp_wput_data(tcp_t *tcp, mblk_t *mp, int sock_id) { int len; mblk_t *local_time; mblk_t *mp1; uchar_t *rptr; uint32_t snxt; int tail_unsent; int tcpstate; int usable = 0; mblk_t *xmit_tail; int32_t num_burst_seg; int32_t mss; int32_t num_sack_blk = 0; int32_t tcp_hdr_len; ipaddr_t *dst; ipaddr_t *src; #ifdef DEBUG printf("tcp_wput_data(%d) ##############################\n", sock_id); #endif tcpstate = tcp->tcp_state; if (mp == NULL) { /* Really tacky... but we need this for detached closes. */ len = tcp->tcp_unsent; goto data_null; } /* * Don't allow data after T_ORDREL_REQ or T_DISCON_REQ, * or before a connection attempt has begun. * * The following should not happen in inetboot.... */ if (tcpstate < TCPS_SYN_SENT || tcpstate > TCPS_CLOSE_WAIT || (tcp->tcp_valid_bits & TCP_FSS_VALID) != 0) { if ((tcp->tcp_valid_bits & TCP_FSS_VALID) != 0) { printf("tcp_wput_data: data after ordrel, %s\n", tcp_display(tcp, NULL, DISP_ADDR_AND_PORT)); } freemsg(mp); return; } /* Strip empties */ for (;;) { assert((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)INT_MAX); len = (int)(mp->b_wptr - mp->b_rptr); if (len > 0) break; mp1 = mp; mp = mp->b_cont; freeb(mp1); if (mp == NULL) { return; } } /* If we are the first on the list ... */ if (tcp->tcp_xmit_head == NULL) { tcp->tcp_xmit_head = mp; tcp->tcp_xmit_tail = mp; tcp->tcp_xmit_tail_unsent = len; } else { tcp->tcp_xmit_last->b_cont = mp; len += tcp->tcp_unsent; } /* Tack on however many more positive length mblks we have */ if ((mp1 = mp->b_cont) != NULL) { do { int tlen; assert((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX); tlen = (int)(mp1->b_wptr - mp1->b_rptr); if (tlen <= 0) { mp->b_cont = mp1->b_cont; freeb(mp1); } else { len += tlen; mp = mp1; } } while ((mp1 = mp->b_cont) != NULL); } tcp->tcp_xmit_last = mp; tcp->tcp_unsent = len; data_null: snxt = tcp->tcp_snxt; xmit_tail = tcp->tcp_xmit_tail; tail_unsent = tcp->tcp_xmit_tail_unsent; /* * Note that tcp_mss has been adjusted to take into account the * timestamp option if applicable. Because SACK options do not * appear in every TCP segments and they are of variable lengths, * they cannot be included in tcp_mss. Thus we need to calculate * the actual segment length when we need to send a segment which * includes SACK options. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) { int32_t opt_len; num_sack_blk = MIN(tcp->tcp_max_sack_blk, tcp->tcp_num_sack_blk); opt_len = num_sack_blk * sizeof (sack_blk_t) + TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN; mss = tcp->tcp_mss - opt_len; tcp_hdr_len = tcp->tcp_hdr_len + opt_len; } else { mss = tcp->tcp_mss; tcp_hdr_len = tcp->tcp_hdr_len; } if ((tcp->tcp_suna == snxt) && (prom_gettime() - tcp->tcp_last_recv_time) >= tcp->tcp_rto) { tcp->tcp_cwnd = MIN(tcp_slow_start_after_idle * mss, MIN(4 * mss, MAX(2 * mss, 4380 / mss * mss))); } if (tcpstate == TCPS_SYN_RCVD) { /* * The three-way connection establishment handshake is not * complete yet. We want to queue the data for transmission * after entering ESTABLISHED state (RFC793). Setting usable to * zero cause a jump to "done" label effectively leaving data * on the queue. */ usable = 0; } else { int usable_r = tcp->tcp_swnd; /* * In the special case when cwnd is zero, which can only * happen if the connection is ECN capable, return now. * New segments is sent using tcp_timer(). The timer * is set in tcp_rput_data(). */ if (tcp->tcp_cwnd == 0) { /* * Note that tcp_cwnd is 0 before 3-way handshake is * finished. */ assert(tcp->tcp_ecn_ok || tcp->tcp_state < TCPS_ESTABLISHED); return; } /* usable = MIN(swnd, cwnd) - unacked_bytes */ if (usable_r > tcp->tcp_cwnd) usable_r = tcp->tcp_cwnd; /* NOTE: trouble if xmitting while SYN not acked? */ usable_r -= snxt; usable_r += tcp->tcp_suna; /* usable = MIN(usable, unsent) */ if (usable_r > len) usable_r = len; /* usable = MAX(usable, {1 for urgent, 0 for data}) */ if (usable_r != 0) usable = usable_r; } /* use uintptr_t to suppress the gcc warning */ local_time = (mblk_t *)(uintptr_t)prom_gettime(); /* * "Our" Nagle Algorithm. This is not the same as in the old * BSD. This is more in line with the true intent of Nagle. * * The conditions are: * 1. The amount of unsent data (or amount of data which can be * sent, whichever is smaller) is less than Nagle limit. * 2. The last sent size is also less than Nagle limit. * 3. There is unack'ed data. * 4. Urgent pointer is not set. Send urgent data ignoring the * Nagle algorithm. This reduces the probability that urgent * bytes get "merged" together. * 5. The app has not closed the connection. This eliminates the * wait time of the receiving side waiting for the last piece of * (small) data. * * If all are satisified, exit without sending anything. Note * that Nagle limit can be smaller than 1 MSS. Nagle limit is * the smaller of 1 MSS and global tcp_naglim_def (default to be * 4095). */ if (usable < (int)tcp->tcp_naglim && tcp->tcp_naglim > tcp->tcp_last_sent_len && snxt != tcp->tcp_suna && !(tcp->tcp_valid_bits & TCP_URG_VALID)) goto done; num_burst_seg = tcp->tcp_snd_burst; for (;;) { tcph_t *tcph; mblk_t *new_mp; if (num_burst_seg-- == 0) goto done; len = mss; if (len > usable) { len = usable; if (len <= 0) { /* Terminate the loop */ goto done; } /* * Sender silly-window avoidance. * Ignore this if we are going to send a * zero window probe out. * * TODO: force data into microscopic window ?? * ==> (!pushed || (unsent > usable)) */ if (len < (tcp->tcp_max_swnd >> 1) && (tcp->tcp_unsent - (snxt - tcp->tcp_snxt)) > len && !((tcp->tcp_valid_bits & TCP_URG_VALID) && len == 1) && (! tcp->tcp_zero_win_probe)) { /* * If the retransmit timer is not running * we start it so that we will retransmit * in the case when the the receiver has * decremented the window. */ if (snxt == tcp->tcp_snxt && snxt == tcp->tcp_suna) { /* * We are not supposed to send * anything. So let's wait a little * bit longer before breaking SWS * avoidance. * * What should the value be? * Suggestion: MAX(init rexmit time, * tcp->tcp_rto) */ TCP_TIMER_RESTART(tcp, tcp->tcp_rto); } goto done; } } tcph = tcp->tcp_tcph; usable -= len; /* Approximate - can be adjusted later */ if (usable > 0) tcph->th_flags[0] = TH_ACK; else tcph->th_flags[0] = (TH_ACK | TH_PUSH); U32_TO_ABE32(snxt, tcph->th_seq); if (tcp->tcp_valid_bits) { uchar_t *prev_rptr = xmit_tail->b_rptr; uint32_t prev_snxt = tcp->tcp_snxt; if (tail_unsent == 0) { assert(xmit_tail->b_cont != NULL); xmit_tail = xmit_tail->b_cont; prev_rptr = xmit_tail->b_rptr; tail_unsent = (int)(xmit_tail->b_wptr - xmit_tail->b_rptr); } else { xmit_tail->b_rptr = xmit_tail->b_wptr - tail_unsent; } mp = tcp_xmit_mp(tcp, xmit_tail, len, NULL, NULL, snxt, B_FALSE, (uint32_t *)&len, B_FALSE); /* Restore tcp_snxt so we get amount sent right. */ tcp->tcp_snxt = prev_snxt; if (prev_rptr == xmit_tail->b_rptr) xmit_tail->b_prev = local_time; else xmit_tail->b_rptr = prev_rptr; if (mp == NULL) break; mp1 = mp->b_cont; snxt += len; tcp->tcp_last_sent_len = (ushort_t)len; while (mp1->b_cont) { xmit_tail = xmit_tail->b_cont; xmit_tail->b_prev = local_time; mp1 = mp1->b_cont; } tail_unsent = xmit_tail->b_wptr - mp1->b_wptr; BUMP_MIB(tcp_mib.tcpOutDataSegs); UPDATE_MIB(tcp_mib.tcpOutDataBytes, len); /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_wput_data (valid bits)", mp); (void) ipv4_tcp_output(sock_id, mp); freeb(mp); continue; } snxt += len; /* Adjust later if we don't send all of len */ BUMP_MIB(tcp_mib.tcpOutDataSegs); UPDATE_MIB(tcp_mib.tcpOutDataBytes, len); if (tail_unsent) { /* Are the bytes above us in flight? */ rptr = xmit_tail->b_wptr - tail_unsent; if (rptr != xmit_tail->b_rptr) { tail_unsent -= len; len += tcp_hdr_len; tcp->tcp_ipha->ip_len = htons(len); mp = dupb(xmit_tail); if (!mp) break; mp->b_rptr = rptr; goto must_alloc; } } else { xmit_tail = xmit_tail->b_cont; assert((uintptr_t)(xmit_tail->b_wptr - xmit_tail->b_rptr) <= (uintptr_t)INT_MAX); tail_unsent = (int)(xmit_tail->b_wptr - xmit_tail->b_rptr); } tail_unsent -= len; tcp->tcp_last_sent_len = (ushort_t)len; len += tcp_hdr_len; if (tcp->tcp_ipversion == IPV4_VERSION) tcp->tcp_ipha->ip_len = htons(len); xmit_tail->b_prev = local_time; mp = dupb(xmit_tail); if (mp == NULL) goto out_of_mem; len = tcp_hdr_len; /* * There are four reasons to allocate a new hdr mblk: * 1) The bytes above us are in use by another packet * 2) We don't have good alignment * 3) The mblk is being shared * 4) We don't have enough room for a header */ rptr = mp->b_rptr - len; if (!OK_32PTR(rptr) || rptr < mp->b_datap) { /* NOTE: we assume allocb returns an OK_32PTR */ must_alloc:; mp1 = allocb(tcp->tcp_ip_hdr_len + TCP_MAX_HDR_LENGTH + tcp_wroff_xtra, 0); if (mp1 == NULL) { freemsg(mp); goto out_of_mem; } mp1->b_cont = mp; mp = mp1; /* Leave room for Link Level header */ len = tcp_hdr_len; rptr = &mp->b_rptr[tcp_wroff_xtra]; mp->b_wptr = &rptr[len]; } if (tcp->tcp_snd_ts_ok) { /* use uintptr_t to suppress the gcc warning */ U32_TO_BE32((uint32_t)(uintptr_t)local_time, (char *)tcph+TCP_MIN_HEADER_LENGTH+4); U32_TO_BE32(tcp->tcp_ts_recent, (char *)tcph+TCP_MIN_HEADER_LENGTH+8); } else { assert(tcp->tcp_tcp_hdr_len == TCP_MIN_HEADER_LENGTH); } mp->b_rptr = rptr; /* Copy the template header. */ dst = (ipaddr_t *)rptr; src = (ipaddr_t *)tcp->tcp_iphc; dst[0] = src[0]; dst[1] = src[1]; dst[2] = src[2]; dst[3] = src[3]; dst[4] = src[4]; dst[5] = src[5]; dst[6] = src[6]; dst[7] = src[7]; dst[8] = src[8]; dst[9] = src[9]; len = tcp->tcp_hdr_len; if (len -= 40) { len >>= 2; dst += 10; src += 10; do { *dst++ = *src++; } while (--len); } /* * Set tcph to point to the header of the outgoing packet, * not to the template header. */ tcph = (tcph_t *)(rptr + tcp->tcp_ip_hdr_len); /* * Set the ECN info in the TCP header if it is not a zero * window probe. Zero window probe is only sent in * tcp_wput_data() and tcp_timer(). */ if (tcp->tcp_ecn_ok && !tcp->tcp_zero_win_probe) { SET_ECT(tcp, rptr); if (tcp->tcp_ecn_echo_on) tcph->th_flags[0] |= TH_ECE; if (tcp->tcp_cwr && !tcp->tcp_ecn_cwr_sent) { tcph->th_flags[0] |= TH_CWR; tcp->tcp_ecn_cwr_sent = B_TRUE; } } /* Fill in SACK options */ if (num_sack_blk > 0) { uchar_t *wptr = rptr + tcp->tcp_hdr_len; sack_blk_t *tmp; int32_t i; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_SACK; wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk * sizeof (sack_blk_t); wptr += TCPOPT_REAL_SACK_LEN; tmp = tcp->tcp_sack_list; for (i = 0; i < num_sack_blk; i++) { U32_TO_BE32(tmp[i].begin, wptr); wptr += sizeof (tcp_seq); U32_TO_BE32(tmp[i].end, wptr); wptr += sizeof (tcp_seq); } tcph->th_offset_and_rsrvd[0] += ((num_sack_blk * 2 + 1) << 4); } if (tail_unsent) { mp1 = mp->b_cont; if (mp1 == NULL) mp1 = mp; /* * If we're a little short, tack on more mblks * as long as we don't need to split an mblk. */ while (tail_unsent < 0 && tail_unsent + (int)(xmit_tail->b_cont->b_wptr - xmit_tail->b_cont->b_rptr) <= 0) { xmit_tail = xmit_tail->b_cont; /* Stash for rtt use later */ xmit_tail->b_prev = local_time; mp1->b_cont = dupb(xmit_tail); mp1 = mp1->b_cont; assert((uintptr_t)(xmit_tail->b_wptr - xmit_tail->b_rptr) <= (uintptr_t)INT_MAX); tail_unsent += (int)(xmit_tail->b_wptr - xmit_tail->b_rptr); if (mp1 == NULL) { freemsg(mp); goto out_of_mem; } } /* Trim back any surplus on the last mblk */ if (tail_unsent > 0) mp1->b_wptr -= tail_unsent; if (tail_unsent < 0) { uint32_t ip_len; /* * We did not send everything we could in * order to preserve mblk boundaries. */ usable -= tail_unsent; snxt += tail_unsent; tcp->tcp_last_sent_len += tail_unsent; UPDATE_MIB(tcp_mib.tcpOutDataBytes, tail_unsent); /* Adjust the IP length field. */ ip_len = ntohs(((struct ip *)rptr)->ip_len) + tail_unsent; ((struct ip *)rptr)->ip_len = htons(ip_len); tail_unsent = 0; } } if (mp == NULL) goto out_of_mem; /* * Performance hit! We need to pullup the whole message * in order to do checksum and for the MAC output routine. */ if (mp->b_cont != NULL) { int mp_size; #ifdef DEBUG printf("Multiple mblk %d\n", msgdsize(mp)); #endif new_mp = allocb(msgdsize(mp) + tcp_wroff_xtra, 0); new_mp->b_rptr += tcp_wroff_xtra; new_mp->b_wptr = new_mp->b_rptr; while (mp != NULL) { mp_size = mp->b_wptr - mp->b_rptr; bcopy(mp->b_rptr, new_mp->b_wptr, mp_size); new_mp->b_wptr += mp_size; mp = mp->b_cont; } freemsg(mp); mp = new_mp; } tcp_set_cksum(mp); ((struct ip *)mp->b_rptr)->ip_ttl = (uint8_t)tcp_ipv4_ttl; TCP_DUMP_PACKET("tcp_wput_data", mp); (void) ipv4_tcp_output(sock_id, mp); freemsg(mp); } out_of_mem:; /* Pretend that all we were trying to send really got sent */ if (tail_unsent < 0) { do { xmit_tail = xmit_tail->b_cont; xmit_tail->b_prev = local_time; assert((uintptr_t)(xmit_tail->b_wptr - xmit_tail->b_rptr) <= (uintptr_t)INT_MAX); tail_unsent += (int)(xmit_tail->b_wptr - xmit_tail->b_rptr); } while (tail_unsent < 0); } done:; tcp->tcp_xmit_tail = xmit_tail; tcp->tcp_xmit_tail_unsent = tail_unsent; len = tcp->tcp_snxt - snxt; if (len) { /* * If new data was sent, need to update the notsack * list, which is, afterall, data blocks that have * not been sack'ed by the receiver. New data is * not sack'ed. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_notsack_list != NULL) { /* len is a negative value. */ tcp->tcp_pipe -= len; tcp_notsack_update(&(tcp->tcp_notsack_list), tcp->tcp_snxt, snxt, &(tcp->tcp_num_notsack_blk), &(tcp->tcp_cnt_notsack_list)); } tcp->tcp_snxt = snxt + tcp->tcp_fin_sent; tcp->tcp_rack = tcp->tcp_rnxt; tcp->tcp_rack_cnt = 0; if ((snxt + len) == tcp->tcp_suna) { TCP_TIMER_RESTART(tcp, tcp->tcp_rto); } /* * Note that len is the amount we just sent but with a negative * sign. We update tcp_unsent here since we may come back to * tcp_wput_data from tcp_state_wait. */ len += tcp->tcp_unsent; tcp->tcp_unsent = len; /* * Let's wait till all the segments have been acked, since we * don't have a timer. */ (void) tcp_state_wait(sock_id, tcp, TCPS_ALL_ACKED); return; } else if (snxt == tcp->tcp_suna && tcp->tcp_swnd == 0) { /* * Didn't send anything. Make sure the timer is running * so that we will probe a zero window. */ TCP_TIMER_RESTART(tcp, tcp->tcp_rto); } /* Note that len is the amount we just sent but with a negative sign */ len += tcp->tcp_unsent; tcp->tcp_unsent = len; } static void tcp_time_wait_processing(tcp_t *tcp, mblk_t *mp, uint32_t seg_seq, uint32_t seg_ack, int seg_len, tcph_t *tcph, int sock_id) { int32_t bytes_acked; int32_t gap; int32_t rgap; tcp_opt_t tcpopt; uint_t flags; uint32_t new_swnd = 0; #ifdef DEBUG printf("Time wait processing called ###############3\n"); #endif /* Just make sure we send the right sock_id to tcp_clean_death */ if ((sockets[sock_id].pcb == NULL) || (sockets[sock_id].pcb != tcp)) sock_id = -1; flags = (unsigned int)tcph->th_flags[0] & 0xFF; new_swnd = BE16_TO_U16(tcph->th_win) << ((tcph->th_flags[0] & TH_SYN) ? 0 : tcp->tcp_snd_ws); if (tcp->tcp_snd_ts_ok) { if (!tcp_paws_check(tcp, tcph, &tcpopt)) { freemsg(mp); tcp_xmit_ctl(NULL, tcp, NULL, tcp->tcp_snxt, tcp->tcp_rnxt, TH_ACK, 0, -1); return; } } gap = seg_seq - tcp->tcp_rnxt; rgap = tcp->tcp_rwnd - (gap + seg_len); if (gap < 0) { BUMP_MIB(tcp_mib.tcpInDataDupSegs); UPDATE_MIB(tcp_mib.tcpInDataDupBytes, (seg_len > -gap ? -gap : seg_len)); seg_len += gap; if (seg_len < 0 || (seg_len == 0 && !(flags & TH_FIN))) { if (flags & TH_RST) { freemsg(mp); return; } if ((flags & TH_FIN) && seg_len == -1) { /* * When TCP receives a duplicate FIN in * TIME_WAIT state, restart the 2 MSL timer. * See page 73 in RFC 793. Make sure this TCP * is already on the TIME_WAIT list. If not, * just restart the timer. */ tcp_time_wait_remove(tcp); tcp_time_wait_append(tcp); TCP_TIMER_RESTART(tcp, tcp_time_wait_interval); tcp_xmit_ctl(NULL, tcp, NULL, tcp->tcp_snxt, tcp->tcp_rnxt, TH_ACK, 0, -1); freemsg(mp); return; } flags |= TH_ACK_NEEDED; seg_len = 0; goto process_ack; } /* Fix seg_seq, and chew the gap off the front. */ seg_seq = tcp->tcp_rnxt; } if ((flags & TH_SYN) && gap > 0 && rgap < 0) { /* * Make sure that when we accept the connection, pick * an ISS greater than (tcp_snxt + ISS_INCR/2) for the * old connection. * * The next ISS generated is equal to tcp_iss_incr_extra * + ISS_INCR/2 + other components depending on the * value of tcp_strong_iss. We pre-calculate the new * ISS here and compare with tcp_snxt to determine if * we need to make adjustment to tcp_iss_incr_extra. * * Note that since we are now in the global queue * perimeter and need to do a lateral_put() to the * listener queue, there can be other connection requests/ * attempts while the lateral_put() is going on. That * means what we calculate here may not be correct. This * is extremely difficult to solve unless TCP and IP * modules are merged and there is no perimeter, but just * locks. The above calculation is ugly and is a * waste of CPU cycles... */ uint32_t new_iss = tcp_iss_incr_extra; int32_t adj; /* Add time component and min random (i.e. 1). */ new_iss += (prom_gettime() >> ISS_NSEC_SHT) + 1; if ((adj = (int32_t)(tcp->tcp_snxt - new_iss)) > 0) { /* * New ISS not guaranteed to be ISS_INCR/2 * ahead of the current tcp_snxt, so add the * difference to tcp_iss_incr_extra. */ tcp_iss_incr_extra += adj; } tcp_clean_death(sock_id, tcp, 0); /* * This is a passive open. Right now we do not * do anything... */ freemsg(mp); return; } /* * rgap is the amount of stuff received out of window. A negative * value is the amount out of window. */ if (rgap < 0) { BUMP_MIB(tcp_mib.tcpInDataPastWinSegs); UPDATE_MIB(tcp_mib.tcpInDataPastWinBytes, -rgap); /* Fix seg_len and make sure there is something left. */ seg_len += rgap; if (seg_len <= 0) { if (flags & TH_RST) { freemsg(mp); return; } flags |= TH_ACK_NEEDED; seg_len = 0; goto process_ack; } } /* * Check whether we can update tcp_ts_recent. This test is * NOT the one in RFC 1323 3.4. It is from Braden, 1993, "TCP * Extensions for High Performance: An Update", Internet Draft. */ if (tcp->tcp_snd_ts_ok && TSTMP_GEQ(tcpopt.tcp_opt_ts_val, tcp->tcp_ts_recent) && SEQ_LEQ(seg_seq, tcp->tcp_rack)) { tcp->tcp_ts_recent = tcpopt.tcp_opt_ts_val; tcp->tcp_last_rcv_lbolt = prom_gettime(); } if (seg_seq != tcp->tcp_rnxt && seg_len > 0) { /* Always ack out of order packets */ flags |= TH_ACK_NEEDED; seg_len = 0; } else if (seg_len > 0) { BUMP_MIB(tcp_mib.tcpInDataInorderSegs); UPDATE_MIB(tcp_mib.tcpInDataInorderBytes, seg_len); } if (flags & TH_RST) { freemsg(mp); (void) tcp_clean_death(sock_id, tcp, 0); return; } if (flags & TH_SYN) { freemsg(mp); tcp_xmit_ctl("TH_SYN", tcp, NULL, seg_ack, seg_seq + 1, TH_RST|TH_ACK, 0, -1); /* * Do not delete the TCP structure if it is in * TIME_WAIT state. Refer to RFC 1122, 4.2.2.13. */ return; } process_ack: if (flags & TH_ACK) { bytes_acked = (int)(seg_ack - tcp->tcp_suna); if (bytes_acked <= 0) { if (bytes_acked == 0 && seg_len == 0 && new_swnd == tcp->tcp_swnd) BUMP_MIB(tcp_mib.tcpInDupAck); } else { /* Acks something not sent */ flags |= TH_ACK_NEEDED; } } freemsg(mp); if (flags & TH_ACK_NEEDED) { /* * Time to send an ack for some reason. */ tcp_xmit_ctl(NULL, tcp, NULL, tcp->tcp_snxt, tcp->tcp_rnxt, TH_ACK, 0, -1); } } static int tcp_init_values(tcp_t *tcp, struct inetboot_socket *isp) { int err; tcp->tcp_family = AF_INET; tcp->tcp_ipversion = IPV4_VERSION; /* * Initialize tcp_rtt_sa and tcp_rtt_sd so that the calculated RTO * will be close to tcp_rexmit_interval_initial. By doing this, we * allow the algorithm to adjust slowly to large fluctuations of RTT * during first few transmissions of a connection as seen in slow * links. */ tcp->tcp_rtt_sa = tcp_rexmit_interval_initial << 2; tcp->tcp_rtt_sd = tcp_rexmit_interval_initial >> 1; tcp->tcp_rto = (tcp->tcp_rtt_sa >> 3) + tcp->tcp_rtt_sd + tcp_rexmit_interval_extra + (tcp->tcp_rtt_sa >> 5) + tcp_conn_grace_period; if (tcp->tcp_rto < tcp_rexmit_interval_min) tcp->tcp_rto = tcp_rexmit_interval_min; tcp->tcp_timer_backoff = 0; tcp->tcp_ms_we_have_waited = 0; tcp->tcp_last_recv_time = prom_gettime(); tcp->tcp_cwnd_max = tcp_cwnd_max_; tcp->tcp_snd_burst = TCP_CWND_INFINITE; tcp->tcp_cwnd_ssthresh = TCP_MAX_LARGEWIN; /* For Ethernet, the mtu returned is actually 1550... */ if (mac_get_type() == IFT_ETHER) { tcp->tcp_if_mtu = mac_get_mtu() - 50; } else { tcp->tcp_if_mtu = mac_get_mtu(); } tcp->tcp_mss = tcp->tcp_if_mtu; tcp->tcp_first_timer_threshold = tcp_ip_notify_interval; tcp->tcp_first_ctimer_threshold = tcp_ip_notify_cinterval; tcp->tcp_second_timer_threshold = tcp_ip_abort_interval; /* * Fix it to tcp_ip_abort_linterval later if it turns out to be a * passive open. */ tcp->tcp_second_ctimer_threshold = tcp_ip_abort_cinterval; tcp->tcp_naglim = tcp_naglim_def; /* NOTE: ISS is now set in tcp_adapt_ire(). */ /* Initialize the header template */ if (tcp->tcp_ipversion == IPV4_VERSION) { err = tcp_header_init_ipv4(tcp); } if (err) return (err); /* * Init the window scale to the max so tcp_rwnd_set() won't pare * down tcp_rwnd. tcp_adapt_ire() will set the right value later. */ tcp->tcp_rcv_ws = TCP_MAX_WINSHIFT; tcp->tcp_xmit_lowater = tcp_xmit_lowat; if (isp != NULL) { tcp->tcp_xmit_hiwater = isp->so_sndbuf; tcp->tcp_rwnd = isp->so_rcvbuf; tcp->tcp_rwnd_max = isp->so_rcvbuf; } tcp->tcp_state = TCPS_IDLE; return (0); } /* * Initialize the IPv4 header. Loses any record of any IP options. */ static int tcp_header_init_ipv4(tcp_t *tcp) { tcph_t *tcph; /* * This is a simple initialization. If there's * already a template, it should never be too small, * so reuse it. Otherwise, allocate space for the new one. */ if (tcp->tcp_iphc != NULL) { assert(tcp->tcp_iphc_len >= TCP_MAX_COMBINED_HEADER_LENGTH); bzero(tcp->tcp_iphc, tcp->tcp_iphc_len); } else { tcp->tcp_iphc_len = TCP_MAX_COMBINED_HEADER_LENGTH; tcp->tcp_iphc = bkmem_zalloc(tcp->tcp_iphc_len); if (tcp->tcp_iphc == NULL) { tcp->tcp_iphc_len = 0; return (ENOMEM); } } tcp->tcp_ipha = (struct ip *)tcp->tcp_iphc; tcp->tcp_ipversion = IPV4_VERSION; /* * Note that it does not include TCP options yet. It will * after the connection is established. */ tcp->tcp_hdr_len = sizeof (struct ip) + sizeof (tcph_t); tcp->tcp_tcp_hdr_len = sizeof (tcph_t); tcp->tcp_ip_hdr_len = sizeof (struct ip); tcp->tcp_ipha->ip_v = IP_VERSION; /* We don't support IP options... */ tcp->tcp_ipha->ip_hl = IP_SIMPLE_HDR_LENGTH_IN_WORDS; tcp->tcp_ipha->ip_p = IPPROTO_TCP; /* We are not supposed to do PMTU discovery... */ tcp->tcp_ipha->ip_sum = 0; tcph = (tcph_t *)(tcp->tcp_iphc + sizeof (struct ip)); tcp->tcp_tcph = tcph; tcph->th_offset_and_rsrvd[0] = (5 << 4); return (0); } /* * Send out a control packet on the tcp connection specified. This routine * is typically called where we need a simple ACK or RST generated. * * This function is called with or without a mp. */ static void tcp_xmit_ctl(char *str, tcp_t *tcp, mblk_t *mp, uint32_t seq, uint32_t ack, int ctl, uint_t ip_hdr_len, int sock_id) { uchar_t *rptr; tcph_t *tcph; struct ip *iph = NULL; int tcp_hdr_len; int tcp_ip_hdr_len; tcp_hdr_len = tcp->tcp_hdr_len; tcp_ip_hdr_len = tcp->tcp_ip_hdr_len; if (mp) { assert(ip_hdr_len != 0); rptr = mp->b_rptr; tcph = (tcph_t *)(rptr + ip_hdr_len); /* Don't reply to a RST segment. */ if (tcph->th_flags[0] & TH_RST) { freeb(mp); return; } freemsg(mp); rptr = NULL; } else { assert(ip_hdr_len == 0); } /* If a text string is passed in with the request, print it out. */ if (str != NULL) { dprintf("tcp_xmit_ctl(%d): '%s', seq 0x%x, ack 0x%x, " "ctl 0x%x\n", sock_id, str, seq, ack, ctl); } mp = allocb(tcp_ip_hdr_len + TCP_MAX_HDR_LENGTH + tcp_wroff_xtra, 0); if (mp == NULL) { dprintf("tcp_xmit_ctl(%d): Cannot allocate memory\n", sock_id); return; } rptr = &mp->b_rptr[tcp_wroff_xtra]; mp->b_rptr = rptr; mp->b_wptr = &rptr[tcp_hdr_len]; bcopy(tcp->tcp_iphc, rptr, tcp_hdr_len); iph = (struct ip *)rptr; iph->ip_len = htons(tcp_hdr_len); tcph = (tcph_t *)&rptr[tcp_ip_hdr_len]; tcph->th_flags[0] = (uint8_t)ctl; if (ctl & TH_RST) { BUMP_MIB(tcp_mib.tcpOutRsts); BUMP_MIB(tcp_mib.tcpOutControl); /* * Don't send TSopt w/ TH_RST packets per RFC 1323. */ if (tcp->tcp_snd_ts_ok && tcp->tcp_state > TCPS_SYN_SENT) { mp->b_wptr = &rptr[tcp_hdr_len - TCPOPT_REAL_TS_LEN]; *(mp->b_wptr) = TCPOPT_EOL; iph->ip_len = htons(tcp_hdr_len - TCPOPT_REAL_TS_LEN); tcph->th_offset_and_rsrvd[0] -= (3 << 4); } } if (ctl & TH_ACK) { uint32_t now = prom_gettime(); if (tcp->tcp_snd_ts_ok) { U32_TO_BE32(now, (char *)tcph+TCP_MIN_HEADER_LENGTH+4); U32_TO_BE32(tcp->tcp_ts_recent, (char *)tcph+TCP_MIN_HEADER_LENGTH+8); } tcp->tcp_rack = ack; tcp->tcp_rack_cnt = 0; BUMP_MIB(tcp_mib.tcpOutAck); } BUMP_MIB(tcp_mib.tcpOutSegs); U32_TO_BE32(seq, tcph->th_seq); U32_TO_BE32(ack, tcph->th_ack); tcp_set_cksum(mp); iph->ip_ttl = (uint8_t)tcp_ipv4_ttl; TCP_DUMP_PACKET("tcp_xmit_ctl", mp); (void) ipv4_tcp_output(sock_id, mp); freeb(mp); } /* Generate an ACK-only (no data) segment for a TCP endpoint */ static mblk_t * tcp_ack_mp(tcp_t *tcp) { if (tcp->tcp_valid_bits) { /* * For the complex case where we have to send some * controls (FIN or SYN), let tcp_xmit_mp do it. * When sending an ACK-only segment (no data) * into a zero window, always set the seq number to * suna, since snxt will be extended past the window. * If we used snxt, the receiver might consider the ACK * unacceptable. */ return (tcp_xmit_mp(tcp, NULL, 0, NULL, NULL, (tcp->tcp_zero_win_probe) ? tcp->tcp_suna : tcp->tcp_snxt, B_FALSE, NULL, B_FALSE)); } else { /* Generate a simple ACK */ uchar_t *rptr; tcph_t *tcph; mblk_t *mp1; int32_t tcp_hdr_len; int32_t num_sack_blk = 0; int32_t sack_opt_len; /* * Allocate space for TCP + IP headers * and link-level header */ if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) { num_sack_blk = MIN(tcp->tcp_max_sack_blk, tcp->tcp_num_sack_blk); sack_opt_len = num_sack_blk * sizeof (sack_blk_t) + TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN; tcp_hdr_len = tcp->tcp_hdr_len + sack_opt_len; } else { tcp_hdr_len = tcp->tcp_hdr_len; } mp1 = allocb(tcp_hdr_len + tcp_wroff_xtra, 0); if (mp1 == NULL) return (NULL); /* copy in prototype TCP + IP header */ rptr = mp1->b_rptr + tcp_wroff_xtra; mp1->b_rptr = rptr; mp1->b_wptr = rptr + tcp_hdr_len; bcopy(tcp->tcp_iphc, rptr, tcp->tcp_hdr_len); tcph = (tcph_t *)&rptr[tcp->tcp_ip_hdr_len]; /* * Set the TCP sequence number. * When sending an ACK-only segment (no data) * into a zero window, always set the seq number to * suna, since snxt will be extended past the window. * If we used snxt, the receiver might consider the ACK * unacceptable. */ U32_TO_ABE32((tcp->tcp_zero_win_probe) ? tcp->tcp_suna : tcp->tcp_snxt, tcph->th_seq); /* Set up the TCP flag field. */ tcph->th_flags[0] = (uchar_t)TH_ACK; if (tcp->tcp_ecn_echo_on) tcph->th_flags[0] |= TH_ECE; tcp->tcp_rack = tcp->tcp_rnxt; tcp->tcp_rack_cnt = 0; /* fill in timestamp option if in use */ if (tcp->tcp_snd_ts_ok) { uint32_t llbolt = (uint32_t)prom_gettime(); U32_TO_BE32(llbolt, (char *)tcph+TCP_MIN_HEADER_LENGTH+4); U32_TO_BE32(tcp->tcp_ts_recent, (char *)tcph+TCP_MIN_HEADER_LENGTH+8); } /* Fill in SACK options */ if (num_sack_blk > 0) { uchar_t *wptr = (uchar_t *)tcph + tcp->tcp_tcp_hdr_len; sack_blk_t *tmp; int32_t i; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_SACK; wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk * sizeof (sack_blk_t); wptr += TCPOPT_REAL_SACK_LEN; tmp = tcp->tcp_sack_list; for (i = 0; i < num_sack_blk; i++) { U32_TO_BE32(tmp[i].begin, wptr); wptr += sizeof (tcp_seq); U32_TO_BE32(tmp[i].end, wptr); wptr += sizeof (tcp_seq); } tcph->th_offset_and_rsrvd[0] += ((num_sack_blk * 2 + 1) << 4); } ((struct ip *)rptr)->ip_len = htons(tcp_hdr_len); tcp_set_cksum(mp1); ((struct ip *)rptr)->ip_ttl = (uint8_t)tcp_ipv4_ttl; return (mp1); } } /* * tcp_xmit_mp is called to return a pointer to an mblk chain complete with * ip and tcp header ready to pass down to IP. If the mp passed in is * non-NULL, then up to max_to_send bytes of data will be dup'ed off that * mblk. (If sendall is not set the dup'ing will stop at an mblk boundary * otherwise it will dup partial mblks.) * Otherwise, an appropriate ACK packet will be generated. This * routine is not usually called to send new data for the first time. It * is mostly called out of the timer for retransmits, and to generate ACKs. * * If offset is not NULL, the returned mblk chain's first mblk's b_rptr will * be adjusted by *offset. And after dupb(), the offset and the ending mblk * of the original mblk chain will be returned in *offset and *end_mp. */ static mblk_t * tcp_xmit_mp(tcp_t *tcp, mblk_t *mp, int32_t max_to_send, int32_t *offset, mblk_t **end_mp, uint32_t seq, boolean_t sendall, uint32_t *seg_len, boolean_t rexmit) { int data_length; int32_t off = 0; uint_t flags; mblk_t *mp1; mblk_t *mp2; mblk_t *new_mp; uchar_t *rptr; tcph_t *tcph; int32_t num_sack_blk = 0; int32_t sack_opt_len = 0; /* Allocate for our maximum TCP header + link-level */ mp1 = allocb(tcp->tcp_ip_hdr_len + TCP_MAX_HDR_LENGTH + tcp_wroff_xtra, 0); if (mp1 == NULL) return (NULL); data_length = 0; /* * Note that tcp_mss has been adjusted to take into account the * timestamp option if applicable. Because SACK options do not * appear in every TCP segments and they are of variable lengths, * they cannot be included in tcp_mss. Thus we need to calculate * the actual segment length when we need to send a segment which * includes SACK options. */ if (tcp->tcp_snd_sack_ok && tcp->tcp_num_sack_blk > 0) { num_sack_blk = MIN(tcp->tcp_max_sack_blk, tcp->tcp_num_sack_blk); sack_opt_len = num_sack_blk * sizeof (sack_blk_t) + TCPOPT_NOP_LEN * 2 + TCPOPT_HEADER_LEN; if (max_to_send + sack_opt_len > tcp->tcp_mss) max_to_send -= sack_opt_len; } if (offset != NULL) { off = *offset; /* We use offset as an indicator that end_mp is not NULL. */ *end_mp = NULL; } for (mp2 = mp1; mp && data_length != max_to_send; mp = mp->b_cont) { /* This could be faster with cooperation from downstream */ if (mp2 != mp1 && !sendall && data_length + (int)(mp->b_wptr - mp->b_rptr) > max_to_send) /* * Don't send the next mblk since the whole mblk * does not fit. */ break; mp2->b_cont = dupb(mp); mp2 = mp2->b_cont; if (mp2 == NULL) { freemsg(mp1); return (NULL); } mp2->b_rptr += off; assert((uintptr_t)(mp2->b_wptr - mp2->b_rptr) <= (uintptr_t)INT_MAX); data_length += (int)(mp2->b_wptr - mp2->b_rptr); if (data_length > max_to_send) { mp2->b_wptr -= data_length - max_to_send; data_length = max_to_send; off = mp2->b_wptr - mp->b_rptr; break; } else { off = 0; } } if (offset != NULL) { *offset = off; *end_mp = mp; } if (seg_len != NULL) { *seg_len = data_length; } rptr = mp1->b_rptr + tcp_wroff_xtra; mp1->b_rptr = rptr; mp1->b_wptr = rptr + tcp->tcp_hdr_len + sack_opt_len; bcopy(tcp->tcp_iphc, rptr, tcp->tcp_hdr_len); tcph = (tcph_t *)&rptr[tcp->tcp_ip_hdr_len]; U32_TO_ABE32(seq, tcph->th_seq); /* * Use tcp_unsent to determine if the PUSH bit should be used assumes * that this function was called from tcp_wput_data. Thus, when called * to retransmit data the setting of the PUSH bit may appear some * what random in that it might get set when it should not. This * should not pose any performance issues. */ if (data_length != 0 && (tcp->tcp_unsent == 0 || tcp->tcp_unsent == data_length)) { flags = TH_ACK | TH_PUSH; } else { flags = TH_ACK; } if (tcp->tcp_ecn_ok) { if (tcp->tcp_ecn_echo_on) flags |= TH_ECE; /* * Only set ECT bit and ECN_CWR if a segment contains new data. * There is no TCP flow control for non-data segments, and * only data segment is transmitted reliably. */ if (data_length > 0 && !rexmit) { SET_ECT(tcp, rptr); if (tcp->tcp_cwr && !tcp->tcp_ecn_cwr_sent) { flags |= TH_CWR; tcp->tcp_ecn_cwr_sent = B_TRUE; } } } if (tcp->tcp_valid_bits) { uint32_t u1; if ((tcp->tcp_valid_bits & TCP_ISS_VALID) && seq == tcp->tcp_iss) { uchar_t *wptr; /* * Tack on the MSS option. It is always needed * for both active and passive open. */ wptr = mp1->b_wptr; wptr[0] = TCPOPT_MAXSEG; wptr[1] = TCPOPT_MAXSEG_LEN; wptr += 2; /* * MSS option value should be interface MTU - MIN * TCP/IP header. */ u1 = tcp->tcp_if_mtu - IP_SIMPLE_HDR_LENGTH - TCP_MIN_HEADER_LENGTH; U16_TO_BE16(u1, wptr); mp1->b_wptr = wptr + 2; /* Update the offset to cover the additional word */ tcph->th_offset_and_rsrvd[0] += (1 << 4); /* * Note that the following way of filling in * TCP options are not optimal. Some NOPs can * be saved. But there is no need at this time * to optimize it. When it is needed, we will * do it. */ switch (tcp->tcp_state) { case TCPS_SYN_SENT: flags = TH_SYN; if (tcp->tcp_snd_ws_ok) { wptr = mp1->b_wptr; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_WSCALE; wptr[2] = TCPOPT_WS_LEN; wptr[3] = (uchar_t)tcp->tcp_rcv_ws; mp1->b_wptr += TCPOPT_REAL_WS_LEN; tcph->th_offset_and_rsrvd[0] += (1 << 4); } if (tcp->tcp_snd_ts_ok) { uint32_t llbolt; llbolt = prom_gettime(); wptr = mp1->b_wptr; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_TSTAMP; wptr[3] = TCPOPT_TSTAMP_LEN; wptr += 4; U32_TO_BE32(llbolt, wptr); wptr += 4; assert(tcp->tcp_ts_recent == 0); U32_TO_BE32(0L, wptr); mp1->b_wptr += TCPOPT_REAL_TS_LEN; tcph->th_offset_and_rsrvd[0] += (3 << 4); } if (tcp->tcp_snd_sack_ok) { wptr = mp1->b_wptr; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_SACK_PERMITTED; wptr[3] = TCPOPT_SACK_OK_LEN; mp1->b_wptr += TCPOPT_REAL_SACK_OK_LEN; tcph->th_offset_and_rsrvd[0] += (1 << 4); } /* * Set up all the bits to tell other side * we are ECN capable. */ if (tcp->tcp_ecn_ok) { flags |= (TH_ECE | TH_CWR); } break; case TCPS_SYN_RCVD: flags |= TH_SYN; if (tcp->tcp_snd_ws_ok) { wptr = mp1->b_wptr; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_WSCALE; wptr[2] = TCPOPT_WS_LEN; wptr[3] = (uchar_t)tcp->tcp_rcv_ws; mp1->b_wptr += TCPOPT_REAL_WS_LEN; tcph->th_offset_and_rsrvd[0] += (1 << 4); } if (tcp->tcp_snd_sack_ok) { wptr = mp1->b_wptr; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_SACK_PERMITTED; wptr[3] = TCPOPT_SACK_OK_LEN; mp1->b_wptr += TCPOPT_REAL_SACK_OK_LEN; tcph->th_offset_and_rsrvd[0] += (1 << 4); } /* * If the other side is ECN capable, reply * that we are also ECN capable. */ if (tcp->tcp_ecn_ok) { flags |= TH_ECE; } break; default: break; } /* allocb() of adequate mblk assures space */ assert((uintptr_t)(mp1->b_wptr - mp1->b_rptr) <= (uintptr_t)INT_MAX); if (flags & TH_SYN) BUMP_MIB(tcp_mib.tcpOutControl); } if ((tcp->tcp_valid_bits & TCP_FSS_VALID) && (seq + data_length) == tcp->tcp_fss) { if (!tcp->tcp_fin_acked) { flags |= TH_FIN; BUMP_MIB(tcp_mib.tcpOutControl); } if (!tcp->tcp_fin_sent) { tcp->tcp_fin_sent = B_TRUE; switch (tcp->tcp_state) { case TCPS_SYN_RCVD: case TCPS_ESTABLISHED: tcp->tcp_state = TCPS_FIN_WAIT_1; break; case TCPS_CLOSE_WAIT: tcp->tcp_state = TCPS_LAST_ACK; break; } if (tcp->tcp_suna == tcp->tcp_snxt) TCP_TIMER_RESTART(tcp, tcp->tcp_rto); tcp->tcp_snxt = tcp->tcp_fss + 1; } } } tcph->th_flags[0] = (uchar_t)flags; tcp->tcp_rack = tcp->tcp_rnxt; tcp->tcp_rack_cnt = 0; if (tcp->tcp_snd_ts_ok) { if (tcp->tcp_state != TCPS_SYN_SENT) { uint32_t llbolt = prom_gettime(); U32_TO_BE32(llbolt, (char *)tcph+TCP_MIN_HEADER_LENGTH+4); U32_TO_BE32(tcp->tcp_ts_recent, (char *)tcph+TCP_MIN_HEADER_LENGTH+8); } } if (num_sack_blk > 0) { uchar_t *wptr = (uchar_t *)tcph + tcp->tcp_tcp_hdr_len; sack_blk_t *tmp; int32_t i; wptr[0] = TCPOPT_NOP; wptr[1] = TCPOPT_NOP; wptr[2] = TCPOPT_SACK; wptr[3] = TCPOPT_HEADER_LEN + num_sack_blk * sizeof (sack_blk_t); wptr += TCPOPT_REAL_SACK_LEN; tmp = tcp->tcp_sack_list; for (i = 0; i < num_sack_blk; i++) { U32_TO_BE32(tmp[i].begin, wptr); wptr += sizeof (tcp_seq); U32_TO_BE32(tmp[i].end, wptr); wptr += sizeof (tcp_seq); } tcph->th_offset_and_rsrvd[0] += ((num_sack_blk * 2 + 1) << 4); } assert((uintptr_t)(mp1->b_wptr - rptr) <= (uintptr_t)INT_MAX); data_length += (int)(mp1->b_wptr - rptr); if (tcp->tcp_ipversion == IPV4_VERSION) ((struct ip *)rptr)->ip_len = htons(data_length); /* * Performance hit! We need to pullup the whole message * in order to do checksum and for the MAC output routine. */ if (mp1->b_cont != NULL) { int mp_size; #ifdef DEBUG printf("Multiple mblk %d\n", msgdsize(mp1)); #endif new_mp = allocb(msgdsize(mp1) + tcp_wroff_xtra, 0); new_mp->b_rptr += tcp_wroff_xtra; new_mp->b_wptr = new_mp->b_rptr; while (mp1 != NULL) { mp_size = mp1->b_wptr - mp1->b_rptr; bcopy(mp1->b_rptr, new_mp->b_wptr, mp_size); new_mp->b_wptr += mp_size; mp1 = mp1->b_cont; } freemsg(mp1); mp1 = new_mp; } tcp_set_cksum(mp1); /* Fill in the TTL field as it is 0 in the header template. */ ((struct ip *)mp1->b_rptr)->ip_ttl = (uint8_t)tcp_ipv4_ttl; return (mp1); } /* * Generate a "no listener here" reset in response to the * connection request contained within 'mp' */ static void tcp_xmit_listeners_reset(int sock_id, mblk_t *mp, uint_t ip_hdr_len) { uchar_t *rptr; uint32_t seg_len; tcph_t *tcph; uint32_t seg_seq; uint32_t seg_ack; uint_t flags; rptr = mp->b_rptr; tcph = (tcph_t *)&rptr[ip_hdr_len]; seg_seq = BE32_TO_U32(tcph->th_seq); seg_ack = BE32_TO_U32(tcph->th_ack); flags = tcph->th_flags[0]; seg_len = msgdsize(mp) - (TCP_HDR_LENGTH(tcph) + ip_hdr_len); if (flags & TH_RST) { freeb(mp); } else if (flags & TH_ACK) { tcp_xmit_early_reset("no tcp, reset", sock_id, mp, seg_ack, 0, TH_RST, ip_hdr_len); } else { if (flags & TH_SYN) seg_len++; tcp_xmit_early_reset("no tcp, reset/ack", sock_id, mp, 0, seg_seq + seg_len, TH_RST | TH_ACK, ip_hdr_len); } } /* Non overlapping byte exchanger */ static void tcp_xchg(uchar_t *a, uchar_t *b, int len) { uchar_t uch; while (len-- > 0) { uch = a[len]; a[len] = b[len]; b[len] = uch; } } /* * Generate a reset based on an inbound packet for which there is no active * tcp state that we can find. */ static void tcp_xmit_early_reset(char *str, int sock_id, mblk_t *mp, uint32_t seq, uint32_t ack, int ctl, uint_t ip_hdr_len) { struct ip *iph = NULL; ushort_t len; tcph_t *tcph; int i; ipaddr_t addr; mblk_t *new_mp; if (str != NULL) { dprintf("tcp_xmit_early_reset: '%s', seq 0x%x, ack 0x%x, " "flags 0x%x\n", str, seq, ack, ctl); } /* * We skip reversing source route here. * (for now we replace all IP options with EOL) */ iph = (struct ip *)mp->b_rptr; for (i = IP_SIMPLE_HDR_LENGTH; i < (int)ip_hdr_len; i++) mp->b_rptr[i] = IPOPT_EOL; /* * Make sure that src address is not a limited broadcast * address. Not all broadcast address checking for the * src address is possible, since we don't know the * netmask of the src addr. * No check for destination address is done, since * IP will not pass up a packet with a broadcast dest address * to TCP. */ if (iph->ip_src.s_addr == INADDR_ANY || iph->ip_src.s_addr == INADDR_BROADCAST) { freemsg(mp); return; } tcph = (tcph_t *)&mp->b_rptr[ip_hdr_len]; if (tcph->th_flags[0] & TH_RST) { freemsg(mp); return; } /* * Now copy the original header to a new buffer. The reason * for doing this is that we need to put extra room before * the header for the MAC layer address. The original mblk * does not have this extra head room. */ len = ip_hdr_len + sizeof (tcph_t); if ((new_mp = allocb(len + tcp_wroff_xtra, 0)) == NULL) { freemsg(mp); return; } new_mp->b_rptr += tcp_wroff_xtra; bcopy(mp->b_rptr, new_mp->b_rptr, len); new_mp->b_wptr = new_mp->b_rptr + len; freemsg(mp); mp = new_mp; iph = (struct ip *)mp->b_rptr; tcph = (tcph_t *)&mp->b_rptr[ip_hdr_len]; tcph->th_offset_and_rsrvd[0] = (5 << 4); tcp_xchg(tcph->th_fport, tcph->th_lport, 2); U32_TO_BE32(ack, tcph->th_ack); U32_TO_BE32(seq, tcph->th_seq); U16_TO_BE16(0, tcph->th_win); bzero(tcph->th_sum, sizeof (int16_t)); tcph->th_flags[0] = (uint8_t)ctl; if (ctl & TH_RST) { BUMP_MIB(tcp_mib.tcpOutRsts); BUMP_MIB(tcp_mib.tcpOutControl); } iph->ip_len = htons(len); /* Swap addresses */ addr = iph->ip_src.s_addr; iph->ip_src = iph->ip_dst; iph->ip_dst.s_addr = addr; iph->ip_id = 0; iph->ip_ttl = 0; tcp_set_cksum(mp); iph->ip_ttl = (uint8_t)tcp_ipv4_ttl; /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_xmit_early_reset", mp); (void) ipv4_tcp_output(sock_id, mp); freemsg(mp); } static void tcp_set_cksum(mblk_t *mp) { struct ip *iph; tcpha_t *tcph; int len; iph = (struct ip *)mp->b_rptr; tcph = (tcpha_t *)(iph + 1); len = ntohs(iph->ip_len); /* * Calculate the TCP checksum. Need to include the psuedo header, * which is similar to the real IP header starting at the TTL field. */ iph->ip_sum = htons(len - IP_SIMPLE_HDR_LENGTH); tcph->tha_sum = 0; tcph->tha_sum = tcp_cksum((uint16_t *)&(iph->ip_ttl), len - IP_SIMPLE_HDR_LENGTH + 12); iph->ip_sum = 0; } static uint16_t tcp_cksum(uint16_t *buf, uint32_t len) { /* * Compute Internet Checksum for "count" bytes * beginning at location "addr". */ int32_t sum = 0; while (len > 1) { /* This is the inner loop */ sum += *buf++; len -= 2; } /* Add left-over byte, if any */ if (len > 0) sum += *(unsigned char *)buf * 256; /* Fold 32-bit sum to 16 bits */ while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16); return ((uint16_t)~sum); } /* * Type three generator adapted from the random() function in 4.4 BSD: */ /* * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* Type 3 -- x**31 + x**3 + 1 */ #define DEG_3 31 #define SEP_3 3 /* Protected by tcp_random_lock */ static int tcp_randtbl[DEG_3 + 1]; static int *tcp_random_fptr = &tcp_randtbl[SEP_3 + 1]; static int *tcp_random_rptr = &tcp_randtbl[1]; static int *tcp_random_state = &tcp_randtbl[1]; static int *tcp_random_end_ptr = &tcp_randtbl[DEG_3 + 1]; static void tcp_random_init(void) { int i; uint32_t hrt; uint32_t wallclock; uint32_t result; /* * * XXX We don't have high resolution time in standalone... The * following is just some approximation on the comment below. * * Use high-res timer and current time for seed. Gethrtime() returns * a longlong, which may contain resolution down to nanoseconds. * The current time will either be a 32-bit or a 64-bit quantity. * XOR the two together in a 64-bit result variable. * Convert the result to a 32-bit value by multiplying the high-order * 32-bits by the low-order 32-bits. * * XXX We don't have gethrtime() in prom and the wallclock.... */ hrt = prom_gettime(); wallclock = (uint32_t)time(NULL); result = wallclock ^ hrt; tcp_random_state[0] = result; for (i = 1; i < DEG_3; i++) tcp_random_state[i] = 1103515245 * tcp_random_state[i - 1] + 12345; tcp_random_fptr = &tcp_random_state[SEP_3]; tcp_random_rptr = &tcp_random_state[0]; for (i = 0; i < 10 * DEG_3; i++) (void) tcp_random(); } /* * tcp_random: Return a random number in the range [1 - (128K + 1)]. * This range is selected to be approximately centered on TCP_ISS / 2, * and easy to compute. We get this value by generating a 32-bit random * number, selecting out the high-order 17 bits, and then adding one so * that we never return zero. */ static int tcp_random(void) { int i; *tcp_random_fptr += *tcp_random_rptr; /* * The high-order bits are more random than the low-order bits, * so we select out the high-order 17 bits and add one so that * we never return zero. */ i = ((*tcp_random_fptr >> 15) & 0x1ffff) + 1; if (++tcp_random_fptr >= tcp_random_end_ptr) { tcp_random_fptr = tcp_random_state; ++tcp_random_rptr; } else if (++tcp_random_rptr >= tcp_random_end_ptr) tcp_random_rptr = tcp_random_state; return (i); } /* * Generate ISS, taking into account NDD changes may happen halfway through. * (If the iss is not zero, set it.) */ static void tcp_iss_init(tcp_t *tcp) { tcp_iss_incr_extra += (ISS_INCR >> 1); tcp->tcp_iss = tcp_iss_incr_extra; tcp->tcp_iss += (prom_gettime() >> ISS_NSEC_SHT) + tcp_random(); tcp->tcp_valid_bits = TCP_ISS_VALID; tcp->tcp_fss = tcp->tcp_iss - 1; tcp->tcp_suna = tcp->tcp_iss; tcp->tcp_snxt = tcp->tcp_iss + 1; tcp->tcp_rexmit_nxt = tcp->tcp_snxt; tcp->tcp_csuna = tcp->tcp_snxt; } /* * Diagnostic routine used to return a string associated with the tcp state. * Note that if the caller does not supply a buffer, it will use an internal * static string. This means that if multiple threads call this function at * the same time, output can be corrupted... Note also that this function * does not check the size of the supplied buffer. The caller has to make * sure that it is big enough. */ static char * tcp_display(tcp_t *tcp, char *sup_buf, char format) { char buf1[30]; static char priv_buf[INET_ADDRSTRLEN * 2 + 80]; char *buf; char *cp; char local_addrbuf[INET_ADDRSTRLEN]; char remote_addrbuf[INET_ADDRSTRLEN]; struct in_addr addr; if (sup_buf != NULL) buf = sup_buf; else buf = priv_buf; if (tcp == NULL) return ("NULL_TCP"); switch (tcp->tcp_state) { case TCPS_CLOSED: cp = "TCP_CLOSED"; break; case TCPS_IDLE: cp = "TCP_IDLE"; break; case TCPS_BOUND: cp = "TCP_BOUND"; break; case TCPS_LISTEN: cp = "TCP_LISTEN"; break; case TCPS_SYN_SENT: cp = "TCP_SYN_SENT"; break; case TCPS_SYN_RCVD: cp = "TCP_SYN_RCVD"; break; case TCPS_ESTABLISHED: cp = "TCP_ESTABLISHED"; break; case TCPS_CLOSE_WAIT: cp = "TCP_CLOSE_WAIT"; break; case TCPS_FIN_WAIT_1: cp = "TCP_FIN_WAIT_1"; break; case TCPS_CLOSING: cp = "TCP_CLOSING"; break; case TCPS_LAST_ACK: cp = "TCP_LAST_ACK"; break; case TCPS_FIN_WAIT_2: cp = "TCP_FIN_WAIT_2"; break; case TCPS_TIME_WAIT: cp = "TCP_TIME_WAIT"; break; default: (void) sprintf(buf1, "TCPUnkState(%d)", tcp->tcp_state); cp = buf1; break; } switch (format) { case DISP_ADDR_AND_PORT: /* * Note that we use the remote address in the tcp_b * structure. This means that it will print out * the real destination address, not the next hop's * address if source routing is used. */ addr.s_addr = tcp->tcp_bound_source; bcopy(inet_ntoa(addr), local_addrbuf, sizeof (local_addrbuf)); addr.s_addr = tcp->tcp_remote; bcopy(inet_ntoa(addr), remote_addrbuf, sizeof (remote_addrbuf)); (void) snprintf(buf, sizeof (priv_buf), "[%s.%u, %s.%u] %s", local_addrbuf, ntohs(tcp->tcp_lport), remote_addrbuf, ntohs(tcp->tcp_fport), cp); break; case DISP_PORT_ONLY: default: (void) snprintf(buf, sizeof (priv_buf), "[%u, %u] %s", ntohs(tcp->tcp_lport), ntohs(tcp->tcp_fport), cp); break; } return (buf); } /* * Add a new piece to the tcp reassembly queue. If the gap at the beginning * is filled, return as much as we can. The message passed in may be * multi-part, chained using b_cont. "start" is the starting sequence * number for this piece. */ static mblk_t * tcp_reass(tcp_t *tcp, mblk_t *mp, uint32_t start) { uint32_t end; mblk_t *mp1; mblk_t *mp2; mblk_t *next_mp; uint32_t u1; /* Walk through all the new pieces. */ do { assert((uintptr_t)(mp->b_wptr - mp->b_rptr) <= (uintptr_t)INT_MAX); end = start + (int)(mp->b_wptr - mp->b_rptr); next_mp = mp->b_cont; if (start == end) { /* Empty. Blast it. */ freeb(mp); continue; } mp->b_cont = NULL; TCP_REASS_SET_SEQ(mp, start); TCP_REASS_SET_END(mp, end); mp1 = tcp->tcp_reass_tail; if (!mp1) { tcp->tcp_reass_tail = mp; tcp->tcp_reass_head = mp; BUMP_MIB(tcp_mib.tcpInDataUnorderSegs); UPDATE_MIB(tcp_mib.tcpInDataUnorderBytes, end - start); continue; } /* New stuff completely beyond tail? */ if (SEQ_GEQ(start, TCP_REASS_END(mp1))) { /* Link it on end. */ mp1->b_cont = mp; tcp->tcp_reass_tail = mp; BUMP_MIB(tcp_mib.tcpInDataUnorderSegs); UPDATE_MIB(tcp_mib.tcpInDataUnorderBytes, end - start); continue; } mp1 = tcp->tcp_reass_head; u1 = TCP_REASS_SEQ(mp1); /* New stuff at the front? */ if (SEQ_LT(start, u1)) { /* Yes... Check for overlap. */ mp->b_cont = mp1; tcp->tcp_reass_head = mp; tcp_reass_elim_overlap(tcp, mp); continue; } /* * The new piece fits somewhere between the head and tail. * We find our slot, where mp1 precedes us and mp2 trails. */ for (; (mp2 = mp1->b_cont) != NULL; mp1 = mp2) { u1 = TCP_REASS_SEQ(mp2); if (SEQ_LEQ(start, u1)) break; } /* Link ourselves in */ mp->b_cont = mp2; mp1->b_cont = mp; /* Trim overlap with following mblk(s) first */ tcp_reass_elim_overlap(tcp, mp); /* Trim overlap with preceding mblk */ tcp_reass_elim_overlap(tcp, mp1); } while (start = end, mp = next_mp); mp1 = tcp->tcp_reass_head; /* Anything ready to go? */ if (TCP_REASS_SEQ(mp1) != tcp->tcp_rnxt) return (NULL); /* Eat what we can off the queue */ for (;;) { mp = mp1->b_cont; end = TCP_REASS_END(mp1); TCP_REASS_SET_SEQ(mp1, 0); TCP_REASS_SET_END(mp1, 0); if (!mp) { tcp->tcp_reass_tail = NULL; break; } if (end != TCP_REASS_SEQ(mp)) { mp1->b_cont = NULL; break; } mp1 = mp; } mp1 = tcp->tcp_reass_head; tcp->tcp_reass_head = mp; return (mp1); } /* Eliminate any overlap that mp may have over later mblks */ static void tcp_reass_elim_overlap(tcp_t *tcp, mblk_t *mp) { uint32_t end; mblk_t *mp1; uint32_t u1; end = TCP_REASS_END(mp); while ((mp1 = mp->b_cont) != NULL) { u1 = TCP_REASS_SEQ(mp1); if (!SEQ_GT(end, u1)) break; if (!SEQ_GEQ(end, TCP_REASS_END(mp1))) { mp->b_wptr -= end - u1; TCP_REASS_SET_END(mp, u1); BUMP_MIB(tcp_mib.tcpInDataPartDupSegs); UPDATE_MIB(tcp_mib.tcpInDataPartDupBytes, end - u1); break; } mp->b_cont = mp1->b_cont; freeb(mp1); BUMP_MIB(tcp_mib.tcpInDataDupSegs); UPDATE_MIB(tcp_mib.tcpInDataDupBytes, end - u1); } if (!mp1) tcp->tcp_reass_tail = mp; } /* * Remove a connection from the list of detached TIME_WAIT connections. */ static void tcp_time_wait_remove(tcp_t *tcp) { if (tcp->tcp_time_wait_expire == 0) { assert(tcp->tcp_time_wait_next == NULL); assert(tcp->tcp_time_wait_prev == NULL); return; } assert(tcp->tcp_state == TCPS_TIME_WAIT); if (tcp == tcp_time_wait_head) { assert(tcp->tcp_time_wait_prev == NULL); tcp_time_wait_head = tcp->tcp_time_wait_next; if (tcp_time_wait_head != NULL) { tcp_time_wait_head->tcp_time_wait_prev = NULL; } else { tcp_time_wait_tail = NULL; } } else if (tcp == tcp_time_wait_tail) { assert(tcp != tcp_time_wait_head); assert(tcp->tcp_time_wait_next == NULL); tcp_time_wait_tail = tcp->tcp_time_wait_prev; assert(tcp_time_wait_tail != NULL); tcp_time_wait_tail->tcp_time_wait_next = NULL; } else { assert(tcp->tcp_time_wait_prev->tcp_time_wait_next == tcp); assert(tcp->tcp_time_wait_next->tcp_time_wait_prev == tcp); tcp->tcp_time_wait_prev->tcp_time_wait_next = tcp->tcp_time_wait_next; tcp->tcp_time_wait_next->tcp_time_wait_prev = tcp->tcp_time_wait_prev; } tcp->tcp_time_wait_next = NULL; tcp->tcp_time_wait_prev = NULL; tcp->tcp_time_wait_expire = 0; } /* * Add a connection to the list of detached TIME_WAIT connections * and set its time to expire ... */ static void tcp_time_wait_append(tcp_t *tcp) { tcp->tcp_time_wait_expire = prom_gettime() + tcp_time_wait_interval; if (tcp->tcp_time_wait_expire == 0) tcp->tcp_time_wait_expire = 1; if (tcp_time_wait_head == NULL) { assert(tcp_time_wait_tail == NULL); tcp_time_wait_head = tcp; } else { assert(tcp_time_wait_tail != NULL); assert(tcp_time_wait_tail->tcp_state == TCPS_TIME_WAIT); tcp_time_wait_tail->tcp_time_wait_next = tcp; tcp->tcp_time_wait_prev = tcp_time_wait_tail; } tcp_time_wait_tail = tcp; /* for ndd stats about compression */ tcp_cum_timewait++; } /* * Periodic qtimeout routine run on the default queue. * Performs 2 functions. * 1. Does TIME_WAIT compression on all recently added tcps. List * traversal is done backwards from the tail. * 2. Blows away all tcps whose TIME_WAIT has expired. List traversal * is done forwards from the head. */ void tcp_time_wait_collector(void) { tcp_t *tcp; uint32_t now; /* * In order to reap time waits reliably, we should use a * source of time that is not adjustable by the user */ now = prom_gettime(); while ((tcp = tcp_time_wait_head) != NULL) { /* * Compare times using modular arithmetic, since * lbolt can wrapover. */ if ((int32_t)(now - tcp->tcp_time_wait_expire) < 0) { break; } /* * Note that the err must be 0 as there is no socket * associated with this TCP... */ (void) tcp_clean_death(-1, tcp, 0); } /* Schedule next run time. */ tcp_time_wait_runtime = prom_gettime() + 10000; } void tcp_time_wait_report(void) { tcp_t *tcp; printf("Current time %u\n", prom_gettime()); for (tcp = tcp_time_wait_head; tcp != NULL; tcp = tcp->tcp_time_wait_next) { printf("%s expires at %u\n", tcp_display(tcp, NULL, DISP_ADDR_AND_PORT), tcp->tcp_time_wait_expire); } } /* * Send up all messages queued on tcp_rcv_list. * Have to set tcp_co_norm since we use putnext. */ static void tcp_rcv_drain(int sock_id, tcp_t *tcp) { mblk_t *mp; struct inetgram *in_gram; mblk_t *in_mp; int len; /* Don't drain if the app has not finished reading all the data. */ if (sockets[sock_id].so_rcvbuf <= 0) return; /* We might have come here just to updated the rwnd */ if (tcp->tcp_rcv_list == NULL) goto win_update; if ((in_gram = (struct inetgram *)bkmem_zalloc( sizeof (struct inetgram))) == NULL) { return; } if ((in_mp = allocb(tcp->tcp_rcv_cnt, 0)) == NULL) { bkmem_free((caddr_t)in_gram, sizeof (struct inetgram)); return; } in_gram->igm_level = APP_LVL; in_gram->igm_mp = in_mp; in_gram->igm_id = 0; while ((mp = tcp->tcp_rcv_list) != NULL) { tcp->tcp_rcv_list = mp->b_cont; len = mp->b_wptr - mp->b_rptr; bcopy(mp->b_rptr, in_mp->b_wptr, len); in_mp->b_wptr += len; freeb(mp); } tcp->tcp_rcv_last_tail = NULL; tcp->tcp_rcv_cnt = 0; add_grams(&sockets[sock_id].inq, in_gram); /* This means that so_rcvbuf can be less than 0. */ sockets[sock_id].so_rcvbuf -= in_mp->b_wptr - in_mp->b_rptr; win_update: /* * Increase the receive window to max. But we need to do receiver * SWS avoidance. This means that we need to check the increase of * of receive window is at least 1 MSS. */ if (sockets[sock_id].so_rcvbuf > 0 && (tcp->tcp_rwnd_max - tcp->tcp_rwnd >= tcp->tcp_mss)) { tcp->tcp_rwnd = tcp->tcp_rwnd_max; U32_TO_ABE16(tcp->tcp_rwnd >> tcp->tcp_rcv_ws, tcp->tcp_tcph->th_win); } } /* * Wrapper for recvfrom to call */ void tcp_rcv_drain_sock(int sock_id) { tcp_t *tcp; if ((tcp = sockets[sock_id].pcb) == NULL) return; tcp_rcv_drain(sock_id, tcp); } /* * If the inq == NULL and the tcp_rcv_list != NULL, we have data that * recvfrom could read. Place a magic message in the inq to let recvfrom * know that it needs to call tcp_rcv_drain_sock to pullup the data. */ static void tcp_drain_needed(int sock_id, tcp_t *tcp) { struct inetgram *in_gram; #ifdef DEBUG printf("tcp_drain_needed: inq %x, tcp_rcv_list %x\n", sockets[sock_id].inq, tcp->tcp_rcv_list); #endif if ((sockets[sock_id].inq != NULL) || (tcp->tcp_rcv_list == NULL)) return; if ((in_gram = (struct inetgram *)bkmem_zalloc( sizeof (struct inetgram))) == NULL) return; in_gram->igm_level = APP_LVL; in_gram->igm_mp = NULL; in_gram->igm_id = TCP_CALLB_MAGIC_ID; add_grams(&sockets[sock_id].inq, in_gram); } /* * Queue data on tcp_rcv_list which is a b_next chain. * Each element of the chain is a b_cont chain. * * M_DATA messages are added to the current element. * Other messages are added as new (b_next) elements. */ static void tcp_rcv_enqueue(tcp_t *tcp, mblk_t *mp, uint_t seg_len) { assert(seg_len == msgdsize(mp)); if (tcp->tcp_rcv_list == NULL) { tcp->tcp_rcv_list = mp; } else { tcp->tcp_rcv_last_tail->b_cont = mp; } while (mp->b_cont) mp = mp->b_cont; tcp->tcp_rcv_last_tail = mp; tcp->tcp_rcv_cnt += seg_len; tcp->tcp_rwnd -= seg_len; #ifdef DEBUG printf("tcp_rcv_enqueue rwnd %d\n", tcp->tcp_rwnd); #endif U32_TO_ABE16(tcp->tcp_rwnd >> tcp->tcp_rcv_ws, tcp->tcp_tcph->th_win); } /* The minimum of smoothed mean deviation in RTO calculation. */ #define TCP_SD_MIN 400 /* * Set RTO for this connection. The formula is from Jacobson and Karels' * "Congestion Avoidance and Control" in SIGCOMM '88. The variable names * are the same as those in Appendix A.2 of that paper. * * m = new measurement * sa = smoothed RTT average (8 * average estimates). * sv = smoothed mean deviation (mdev) of RTT (4 * deviation estimates). */ static void tcp_set_rto(tcp_t *tcp, int32_t rtt) { int32_t m = rtt; uint32_t sa = tcp->tcp_rtt_sa; uint32_t sv = tcp->tcp_rtt_sd; uint32_t rto; BUMP_MIB(tcp_mib.tcpRttUpdate); tcp->tcp_rtt_update++; /* tcp_rtt_sa is not 0 means this is a new sample. */ if (sa != 0) { /* * Update average estimator: * new rtt = 7/8 old rtt + 1/8 Error */ /* m is now Error in estimate. */ m -= sa >> 3; if ((int32_t)(sa += m) <= 0) { /* * Don't allow the smoothed average to be negative. * We use 0 to denote reinitialization of the * variables. */ sa = 1; } /* * Update deviation estimator: * new mdev = 3/4 old mdev + 1/4 (abs(Error) - old mdev) */ if (m < 0) m = -m; m -= sv >> 2; sv += m; } else { /* * This follows BSD's implementation. So the reinitialized * RTO is 3 * m. We cannot go less than 2 because if the * link is bandwidth dominated, doubling the window size * during slow start means doubling the RTT. We want to be * more conservative when we reinitialize our estimates. 3 * is just a convenient number. */ sa = m << 3; sv = m << 1; } if (sv < TCP_SD_MIN) { /* * We do not know that if sa captures the delay ACK * effect as in a long train of segments, a receiver * does not delay its ACKs. So set the minimum of sv * to be TCP_SD_MIN, which is default to 400 ms, twice * of BSD DATO. That means the minimum of mean * deviation is 100 ms. * */ sv = TCP_SD_MIN; } tcp->tcp_rtt_sa = sa; tcp->tcp_rtt_sd = sv; /* * RTO = average estimates (sa / 8) + 4 * deviation estimates (sv) * * Add tcp_rexmit_interval extra in case of extreme environment * where the algorithm fails to work. The default value of * tcp_rexmit_interval_extra should be 0. * * As we use a finer grained clock than BSD and update * RTO for every ACKs, add in another .25 of RTT to the * deviation of RTO to accomodate burstiness of 1/4 of * window size. */ rto = (sa >> 3) + sv + tcp_rexmit_interval_extra + (sa >> 5); if (rto > tcp_rexmit_interval_max) { tcp->tcp_rto = tcp_rexmit_interval_max; } else if (rto < tcp_rexmit_interval_min) { tcp->tcp_rto = tcp_rexmit_interval_min; } else { tcp->tcp_rto = rto; } /* Now, we can reset tcp_timer_backoff to use the new RTO... */ tcp->tcp_timer_backoff = 0; } /* * Initiate closedown sequence on an active connection. * Return value zero for OK return, non-zero for error return. */ static int tcp_xmit_end(tcp_t *tcp, int sock_id) { mblk_t *mp; if (tcp->tcp_state < TCPS_SYN_RCVD || tcp->tcp_state > TCPS_CLOSE_WAIT) { /* * Invalid state, only states TCPS_SYN_RCVD, * TCPS_ESTABLISHED and TCPS_CLOSE_WAIT are valid */ return (-1); } tcp->tcp_fss = tcp->tcp_snxt + tcp->tcp_unsent; tcp->tcp_valid_bits |= TCP_FSS_VALID; /* * If there is nothing more unsent, send the FIN now. * Otherwise, it will go out with the last segment. */ if (tcp->tcp_unsent == 0) { mp = tcp_xmit_mp(tcp, NULL, 0, NULL, NULL, tcp->tcp_fss, B_FALSE, NULL, B_FALSE); if (mp != NULL) { /* Dump the packet when debugging. */ TCP_DUMP_PACKET("tcp_xmit_end", mp); (void) ipv4_tcp_output(sock_id, mp); freeb(mp); } else { /* * Couldn't allocate msg. Pretend we got it out. * Wait for rexmit timeout. */ tcp->tcp_snxt = tcp->tcp_fss + 1; TCP_TIMER_RESTART(tcp, tcp->tcp_rto); } /* * If needed, update tcp_rexmit_snxt as tcp_snxt is * changed. */ if (tcp->tcp_rexmit && tcp->tcp_rexmit_nxt == tcp->tcp_fss) { tcp->tcp_rexmit_nxt = tcp->tcp_snxt; } } else { tcp_wput_data(tcp, NULL, B_FALSE); } return (0); } int tcp_opt_set(tcp_t *tcp, int level, int option, const void *optval, socklen_t optlen) { switch (level) { case SOL_SOCKET: { switch (option) { case SO_RCVBUF: if (optlen == sizeof (int)) { int val = *(int *)optval; if (val > tcp_max_buf) { errno = ENOBUFS; break; } /* Silently ignore zero */ if (val != 0) { val = MSS_ROUNDUP(val, tcp->tcp_mss); (void) tcp_rwnd_set(tcp, val); } } else { errno = EINVAL; } break; case SO_SNDBUF: if (optlen == sizeof (int)) { tcp->tcp_xmit_hiwater = *(int *)optval; if (tcp->tcp_xmit_hiwater > tcp_max_buf) tcp->tcp_xmit_hiwater = tcp_max_buf; } else { errno = EINVAL; } break; case SO_LINGER: if (optlen == sizeof (struct linger)) { struct linger *lgr = (struct linger *)optval; if (lgr->l_onoff) { tcp->tcp_linger = 1; tcp->tcp_lingertime = lgr->l_linger; } else { tcp->tcp_linger = 0; tcp->tcp_lingertime = 0; } } else { errno = EINVAL; } break; default: errno = ENOPROTOOPT; break; } break; } /* case SOL_SOCKET */ case IPPROTO_TCP: { switch (option) { default: errno = ENOPROTOOPT; break; } break; } /* case IPPROTO_TCP */ case IPPROTO_IP: { switch (option) { default: errno = ENOPROTOOPT; break; } break; } /* case IPPROTO_IP */ default: errno = ENOPROTOOPT; break; } /* switch (level) */ if (errno != 0) return (-1); else return (0); }