1 /* 2 * net/dccp/minisocks.c 3 * 4 * An implementation of the DCCP protocol 5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 */ 12 13 #include <linux/dccp.h> 14 #include <linux/gfp.h> 15 #include <linux/kernel.h> 16 #include <linux/skbuff.h> 17 #include <linux/timer.h> 18 19 #include <net/sock.h> 20 #include <net/xfrm.h> 21 #include <net/inet_timewait_sock.h> 22 23 #include "ackvec.h" 24 #include "ccid.h" 25 #include "dccp.h" 26 #include "feat.h" 27 28 struct inet_timewait_death_row dccp_death_row = { 29 .sysctl_max_tw_buckets = NR_FILE * 2, 30 .period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS, 31 .death_lock = __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock), 32 .hashinfo = &dccp_hashinfo, 33 .tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0, 34 (unsigned long)&dccp_death_row), 35 .twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work, 36 inet_twdr_twkill_work), 37 /* Short-time timewait calendar */ 38 39 .twcal_hand = -1, 40 .twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0, 41 (unsigned long)&dccp_death_row), 42 }; 43 44 EXPORT_SYMBOL_GPL(dccp_death_row); 45 46 void dccp_time_wait(struct sock *sk, int state, int timeo) 47 { 48 struct inet_timewait_sock *tw = NULL; 49 50 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets) 51 tw = inet_twsk_alloc(sk, state); 52 53 if (tw != NULL) { 54 const struct inet_connection_sock *icsk = inet_csk(sk); 55 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); 56 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 57 if (tw->tw_family == PF_INET6) { 58 const struct ipv6_pinfo *np = inet6_sk(sk); 59 struct inet6_timewait_sock *tw6; 60 61 tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot); 62 tw6 = inet6_twsk((struct sock *)tw); 63 ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr); 64 ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr); 65 tw->tw_ipv6only = np->ipv6only; 66 } 67 #endif 68 /* Linkage updates. */ 69 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); 70 71 /* Get the TIME_WAIT timeout firing. */ 72 if (timeo < rto) 73 timeo = rto; 74 75 tw->tw_timeout = DCCP_TIMEWAIT_LEN; 76 if (state == DCCP_TIME_WAIT) 77 timeo = DCCP_TIMEWAIT_LEN; 78 79 inet_twsk_schedule(tw, &dccp_death_row, timeo, 80 DCCP_TIMEWAIT_LEN); 81 inet_twsk_put(tw); 82 } else { 83 /* Sorry, if we're out of memory, just CLOSE this 84 * socket up. We've got bigger problems than 85 * non-graceful socket closings. 86 */ 87 DCCP_WARN("time wait bucket table overflow\n"); 88 } 89 90 dccp_done(sk); 91 } 92 93 struct sock *dccp_create_openreq_child(struct sock *sk, 94 const struct request_sock *req, 95 const struct sk_buff *skb) 96 { 97 /* 98 * Step 3: Process LISTEN state 99 * 100 * (* Generate a new socket and switch to that socket *) 101 * Set S := new socket for this port pair 102 */ 103 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); 104 105 if (newsk != NULL) { 106 struct dccp_request_sock *dreq = dccp_rsk(req); 107 struct inet_connection_sock *newicsk = inet_csk(newsk); 108 struct dccp_sock *newdp = dccp_sk(newsk); 109 110 newdp->dccps_role = DCCP_ROLE_SERVER; 111 newdp->dccps_hc_rx_ackvec = NULL; 112 newdp->dccps_service_list = NULL; 113 newdp->dccps_service = dreq->dreq_service; 114 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo; 115 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; 116 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 117 118 INIT_LIST_HEAD(&newdp->dccps_featneg); 119 /* 120 * Step 3: Process LISTEN state 121 * 122 * Choose S.ISS (initial seqno) or set from Init Cookies 123 * Initialize S.GAR := S.ISS 124 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 125 */ 126 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss; 127 dccp_update_gss(newsk, dreq->dreq_iss); 128 129 newdp->dccps_isr = dreq->dreq_isr; 130 dccp_update_gsr(newsk, dreq->dreq_isr); 131 132 /* 133 * SWL and AWL are initially adjusted so that they are not less than 134 * the initial Sequence Numbers received and sent, respectively: 135 * SWL := max(GSR + 1 - floor(W/4), ISR), 136 * AWL := max(GSS - W' + 1, ISS). 137 * These adjustments MUST be applied only at the beginning of the 138 * connection. 139 */ 140 dccp_set_seqno(&newdp->dccps_swl, 141 max48(newdp->dccps_swl, newdp->dccps_isr)); 142 dccp_set_seqno(&newdp->dccps_awl, 143 max48(newdp->dccps_awl, newdp->dccps_iss)); 144 145 /* 146 * Activate features after initialising the sequence numbers, 147 * since CCID initialisation may depend on GSS, ISR, ISS etc. 148 */ 149 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) { 150 /* It is still raw copy of parent, so invalidate 151 * destructor and make plain sk_free() */ 152 newsk->sk_destruct = NULL; 153 sk_free(newsk); 154 return NULL; 155 } 156 dccp_init_xmit_timers(newsk); 157 158 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 159 } 160 return newsk; 161 } 162 163 EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 164 165 /* 166 * Process an incoming packet for RESPOND sockets represented 167 * as an request_sock. 168 */ 169 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 170 struct request_sock *req, 171 struct request_sock **prev) 172 { 173 struct sock *child = NULL; 174 struct dccp_request_sock *dreq = dccp_rsk(req); 175 176 /* Check for retransmitted REQUEST */ 177 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 178 179 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) { 180 dccp_pr_debug("Retransmitted REQUEST\n"); 181 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq; 182 /* 183 * Send another RESPONSE packet 184 * To protect against Request floods, increment retrans 185 * counter (backoff, monitored by dccp_response_timer). 186 */ 187 req->retrans++; 188 req->rsk_ops->rtx_syn_ack(sk, req, NULL); 189 } 190 /* Network Duplicate, discard packet */ 191 return NULL; 192 } 193 194 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 195 196 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 197 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 198 goto drop; 199 200 /* Invalid ACK */ 201 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) { 202 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 203 "dreq_iss=%llu\n", 204 (unsigned long long) 205 DCCP_SKB_CB(skb)->dccpd_ack_seq, 206 (unsigned long long) dreq->dreq_iss); 207 goto drop; 208 } 209 210 if (dccp_parse_options(sk, dreq, skb)) 211 goto drop; 212 213 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); 214 if (child == NULL) 215 goto listen_overflow; 216 217 inet_csk_reqsk_queue_unlink(sk, req, prev); 218 inet_csk_reqsk_queue_removed(sk, req); 219 inet_csk_reqsk_queue_add(sk, req, child); 220 out: 221 return child; 222 listen_overflow: 223 dccp_pr_debug("listen_overflow!\n"); 224 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 225 drop: 226 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 227 req->rsk_ops->send_reset(sk, skb); 228 229 inet_csk_reqsk_queue_drop(sk, req, prev); 230 goto out; 231 } 232 233 EXPORT_SYMBOL_GPL(dccp_check_req); 234 235 /* 236 * Queue segment on the new socket if the new socket is active, 237 * otherwise we just shortcircuit this and continue with 238 * the new socket. 239 */ 240 int dccp_child_process(struct sock *parent, struct sock *child, 241 struct sk_buff *skb) 242 { 243 int ret = 0; 244 const int state = child->sk_state; 245 246 if (!sock_owned_by_user(child)) { 247 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 248 skb->len); 249 250 /* Wakeup parent, send SIGIO */ 251 if (state == DCCP_RESPOND && child->sk_state != state) 252 parent->sk_data_ready(parent, 0); 253 } else { 254 /* Alas, it is possible again, because we do lookup 255 * in main socket hash table and lock on listening 256 * socket does not protect us more. 257 */ 258 __sk_add_backlog(child, skb); 259 } 260 261 bh_unlock_sock(child); 262 sock_put(child); 263 return ret; 264 } 265 266 EXPORT_SYMBOL_GPL(dccp_child_process); 267 268 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 269 struct request_sock *rsk) 270 { 271 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); 272 } 273 274 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); 275 276 int dccp_reqsk_init(struct request_sock *req, 277 struct dccp_sock const *dp, struct sk_buff const *skb) 278 { 279 struct dccp_request_sock *dreq = dccp_rsk(req); 280 281 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; 282 inet_rsk(req)->loc_port = dccp_hdr(skb)->dccph_dport; 283 inet_rsk(req)->acked = 0; 284 dreq->dreq_timestamp_echo = 0; 285 286 /* inherit feature negotiation options from listening socket */ 287 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg); 288 } 289 290 EXPORT_SYMBOL_GPL(dccp_reqsk_init); 291