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