1 /* 2 * Copyright (c) 1982, 1986, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp_var.h 8.3 (Berkeley) 4/10/94 34 */ 35 36 /* 37 * Kernel variables for tcp. 38 */ 39 40 /* 41 * Tcp control block, one per tcp; fields: 42 */ 43 struct tcpcb { 44 struct tcpiphdr *seg_next; /* sequencing queue */ 45 struct tcpiphdr *seg_prev; 46 short t_state; /* state of this connection */ 47 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 48 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 49 short t_rxtcur; /* current retransmit value */ 50 short t_dupacks; /* consecutive dup acks recd */ 51 u_short t_maxseg; /* maximum segment size */ 52 char t_force; /* 1 if forcing out a byte */ 53 u_short t_flags; 54 #define TF_ACKNOW 0x0001 /* ack peer immediately */ 55 #define TF_DELACK 0x0002 /* ack, but try to delay it */ 56 #define TF_NODELAY 0x0004 /* don't delay packets to coalesce */ 57 #define TF_NOOPT 0x0008 /* don't use tcp options */ 58 #define TF_SENTFIN 0x0010 /* have sent FIN */ 59 #define TF_REQ_SCALE 0x0020 /* have/will request window scaling */ 60 #define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */ 61 #define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */ 62 #define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */ 63 #define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */ 64 65 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 66 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 67 /* 68 * The following fields are used as in the protocol specification. 69 * See RFC783, Dec. 1981, page 21. 70 */ 71 /* send sequence variables */ 72 tcp_seq snd_una; /* send unacknowledged */ 73 tcp_seq snd_nxt; /* send next */ 74 tcp_seq snd_up; /* send urgent pointer */ 75 tcp_seq snd_wl1; /* window update seg seq number */ 76 tcp_seq snd_wl2; /* window update seg ack number */ 77 tcp_seq iss; /* initial send sequence number */ 78 u_long snd_wnd; /* send window */ 79 /* receive sequence variables */ 80 u_long rcv_wnd; /* receive window */ 81 tcp_seq rcv_nxt; /* receive next */ 82 tcp_seq rcv_up; /* receive urgent pointer */ 83 tcp_seq irs; /* initial receive sequence number */ 84 /* 85 * Additional variables for this implementation. 86 */ 87 /* receive variables */ 88 tcp_seq rcv_adv; /* advertised window */ 89 /* retransmit variables */ 90 tcp_seq snd_max; /* highest sequence number sent; 91 * used to recognize retransmits 92 */ 93 /* congestion control (for slow start, source quench, retransmit after loss) */ 94 u_long snd_cwnd; /* congestion-controlled window */ 95 u_long snd_ssthresh; /* snd_cwnd size threshhold for 96 * for slow start exponential to 97 * linear switch 98 */ 99 /* 100 * transmit timing stuff. See below for scale of srtt and rttvar. 101 * "Variance" is actually smoothed difference. 102 */ 103 short t_idle; /* inactivity time */ 104 short t_rtt; /* round trip time */ 105 tcp_seq t_rtseq; /* sequence number being timed */ 106 short t_srtt; /* smoothed round-trip time */ 107 short t_rttvar; /* variance in round-trip time */ 108 u_short t_rttmin; /* minimum rtt allowed */ 109 u_long max_sndwnd; /* largest window peer has offered */ 110 111 /* out-of-band data */ 112 char t_oobflags; /* have some */ 113 char t_iobc; /* input character */ 114 #define TCPOOB_HAVEDATA 0x01 115 #define TCPOOB_HADDATA 0x02 116 short t_softerror; /* possible error not yet reported */ 117 118 /* RFC 1323 variables */ 119 u_char snd_scale; /* window scaling for send window */ 120 u_char rcv_scale; /* window scaling for recv window */ 121 u_char request_r_scale; /* pending window scaling */ 122 u_char requested_s_scale; 123 u_long ts_recent; /* timestamp echo data */ 124 u_long ts_recent_age; /* when last updated */ 125 tcp_seq last_ack_sent; 126 127 /* TUBA stuff */ 128 caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */ 129 }; 130 131 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 132 #define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 133 134 /* 135 * The smoothed round-trip time and estimated variance 136 * are stored as fixed point numbers scaled by the values below. 137 * For convenience, these scales are also used in smoothing the average 138 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 139 * With these scales, srtt has 3 bits to the right of the binary point, 140 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 141 * binary point, and is smoothed with an ALPHA of 0.75. 142 */ 143 #define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */ 144 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 145 #define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */ 146 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 147 148 /* 149 * The initial retransmission should happen at rtt + 4 * rttvar. 150 * Because of the way we do the smoothing, srtt and rttvar 151 * will each average +1/2 tick of bias. When we compute 152 * the retransmit timer, we want 1/2 tick of rounding and 153 * 1 extra tick because of +-1/2 tick uncertainty in the 154 * firing of the timer. The bias will give us exactly the 155 * 1.5 tick we need. But, because the bias is 156 * statistical, we have to test that we don't drop below 157 * the minimum feasible timer (which is 2 ticks). 158 * This macro assumes that the value of TCP_RTTVAR_SCALE 159 * is the same as the multiplier for rttvar. 160 */ 161 #define TCP_REXMTVAL(tp) \ 162 (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) 163 164 /* XXX 165 * We want to avoid doing m_pullup on incoming packets but that 166 * means avoiding dtom on the tcp reassembly code. That in turn means 167 * keeping an mbuf pointer in the reassembly queue (since we might 168 * have a cluster). As a quick hack, the source & destination 169 * port numbers (which are no longer needed once we've located the 170 * tcpcb) are overlayed with an mbuf pointer. 171 */ 172 #define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t)) 173 174 /* 175 * TCP statistics. 176 * Many of these should be kept per connection, 177 * but that's inconvenient at the moment. 178 */ 179 struct tcpstat { 180 u_long tcps_connattempt; /* connections initiated */ 181 u_long tcps_accepts; /* connections accepted */ 182 u_long tcps_connects; /* connections established */ 183 u_long tcps_drops; /* connections dropped */ 184 u_long tcps_conndrops; /* embryonic connections dropped */ 185 u_long tcps_closed; /* conn. closed (includes drops) */ 186 u_long tcps_segstimed; /* segs where we tried to get rtt */ 187 u_long tcps_rttupdated; /* times we succeeded */ 188 u_long tcps_delack; /* delayed acks sent */ 189 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 190 u_long tcps_rexmttimeo; /* retransmit timeouts */ 191 u_long tcps_persisttimeo; /* persist timeouts */ 192 u_long tcps_keeptimeo; /* keepalive timeouts */ 193 u_long tcps_keepprobe; /* keepalive probes sent */ 194 u_long tcps_keepdrops; /* connections dropped in keepalive */ 195 196 u_long tcps_sndtotal; /* total packets sent */ 197 u_long tcps_sndpack; /* data packets sent */ 198 u_long tcps_sndbyte; /* data bytes sent */ 199 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 200 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 201 u_long tcps_sndacks; /* ack-only packets sent */ 202 u_long tcps_sndprobe; /* window probes sent */ 203 u_long tcps_sndurg; /* packets sent with URG only */ 204 u_long tcps_sndwinup; /* window update-only packets sent */ 205 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 206 207 u_long tcps_rcvtotal; /* total packets received */ 208 u_long tcps_rcvpack; /* packets received in sequence */ 209 u_long tcps_rcvbyte; /* bytes received in sequence */ 210 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 211 u_long tcps_rcvbadoff; /* packets received with bad offset */ 212 u_long tcps_rcvshort; /* packets received too short */ 213 u_long tcps_rcvduppack; /* duplicate-only packets received */ 214 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 215 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 216 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 217 u_long tcps_rcvoopack; /* out-of-order packets received */ 218 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 219 u_long tcps_rcvpackafterwin; /* packets with data after window */ 220 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 221 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 222 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 223 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 224 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 225 u_long tcps_rcvackpack; /* rcvd ack packets */ 226 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 227 u_long tcps_rcvwinupd; /* rcvd window update packets */ 228 u_long tcps_pawsdrop; /* segments dropped due to PAWS */ 229 u_long tcps_predack; /* times hdr predict ok for acks */ 230 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 231 u_long tcps_pcbcachemiss; 232 }; 233 234 #ifdef KERNEL 235 struct inpcb tcb; /* head of queue of active tcpcb's */ 236 struct tcpstat tcpstat; /* tcp statistics */ 237 u_long tcp_now; /* for RFC 1323 timestamps */ 238 239 int tcp_attach __P((struct socket *)); 240 void tcp_canceltimers __P((struct tcpcb *)); 241 struct tcpcb * 242 tcp_close __P((struct tcpcb *)); 243 void tcp_ctlinput __P((int, struct sockaddr *, struct ip *)); 244 int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **)); 245 struct tcpcb * 246 tcp_disconnect __P((struct tcpcb *)); 247 struct tcpcb * 248 tcp_drop __P((struct tcpcb *, int)); 249 void tcp_dooptions __P((struct tcpcb *, 250 u_char *, int, struct tcpiphdr *, int *, u_long *, u_long *)); 251 void tcp_drain __P((void)); 252 void tcp_fasttimo __P((void)); 253 void tcp_init __P((void)); 254 void tcp_input __P((struct mbuf *, int)); 255 int tcp_mss __P((struct tcpcb *, u_int)); 256 struct tcpcb * 257 tcp_newtcpcb __P((struct inpcb *)); 258 void tcp_notify __P((struct inpcb *, int)); 259 int tcp_output __P((struct tcpcb *)); 260 void tcp_pulloutofband __P((struct socket *, 261 struct tcpiphdr *, struct mbuf *)); 262 void tcp_quench __P((struct inpcb *, int)); 263 int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); 264 void tcp_respond __P((struct tcpcb *, 265 struct tcpiphdr *, struct mbuf *, u_long, u_long, int)); 266 void tcp_setpersist __P((struct tcpcb *)); 267 void tcp_slowtimo __P((void)); 268 struct tcpiphdr * 269 tcp_template __P((struct tcpcb *)); 270 struct tcpcb * 271 tcp_timers __P((struct tcpcb *, int)); 272 void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int)); 273 struct tcpcb * 274 tcp_usrclosed __P((struct tcpcb *)); 275 int tcp_usrreq __P((struct socket *, 276 int, struct mbuf *, struct mbuf *, struct mbuf *)); 277 void tcp_xmit_timer __P((struct tcpcb *, int)); 278 #endif 279