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/config.h> 14 #include <linux/dccp.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 26 struct inet_timewait_death_row dccp_death_row = { 27 .sysctl_max_tw_buckets = NR_FILE * 2, 28 .period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS, 29 .death_lock = SPIN_LOCK_UNLOCKED, 30 .hashinfo = &dccp_hashinfo, 31 .tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0, 32 (unsigned long)&dccp_death_row), 33 .twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work, 34 inet_twdr_twkill_work, 35 &dccp_death_row), 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 LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket " 87 "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 const struct dccp_request_sock *dreq = dccp_rsk(req); 107 struct inet_connection_sock *newicsk = inet_csk(sk); 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 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 115 do_gettimeofday(&newdp->dccps_epoch); 116 117 if (newdp->dccps_options.dccpo_send_ack_vector) { 118 newdp->dccps_hc_rx_ackvec = 119 dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN, 120 GFP_ATOMIC); 121 /* 122 * XXX: We're using the same CCIDs set on the parent, 123 * i.e. sk_clone copied the master sock and left the 124 * CCID pointers for this child, that is why we do the 125 * __ccid_get calls. 126 */ 127 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) 128 goto out_free; 129 } 130 131 if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid, 132 newsk) != 0 || 133 ccid_hc_tx_init(newdp->dccps_hc_tx_ccid, 134 newsk) != 0)) { 135 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); 136 ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk); 137 ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk); 138 out_free: 139 /* It is still raw copy of parent, so invalidate 140 * destructor and make plain sk_free() */ 141 newsk->sk_destruct = NULL; 142 sk_free(newsk); 143 return NULL; 144 } 145 146 __ccid_get(newdp->dccps_hc_rx_ccid); 147 __ccid_get(newdp->dccps_hc_tx_ccid); 148 149 /* 150 * Step 3: Process LISTEN state 151 * 152 * Choose S.ISS (initial seqno) or set from Init Cookie 153 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init 154 * Cookie 155 */ 156 157 /* See dccp_v4_conn_request */ 158 newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd; 159 160 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr; 161 dccp_update_gsr(newsk, dreq->dreq_isr); 162 163 newdp->dccps_iss = dreq->dreq_iss; 164 dccp_update_gss(newsk, dreq->dreq_iss); 165 166 /* 167 * SWL and AWL are initially adjusted so that they are not less than 168 * the initial Sequence Numbers received and sent, respectively: 169 * SWL := max(GSR + 1 - floor(W/4), ISR), 170 * AWL := max(GSS - W' + 1, ISS). 171 * These adjustments MUST be applied only at the beginning of the 172 * connection. 173 */ 174 dccp_set_seqno(&newdp->dccps_swl, 175 max48(newdp->dccps_swl, newdp->dccps_isr)); 176 dccp_set_seqno(&newdp->dccps_awl, 177 max48(newdp->dccps_awl, newdp->dccps_iss)); 178 179 dccp_init_xmit_timers(newsk); 180 181 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 182 } 183 return newsk; 184 } 185 186 EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 187 188 /* 189 * Process an incoming packet for RESPOND sockets represented 190 * as an request_sock. 191 */ 192 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 193 struct request_sock *req, 194 struct request_sock **prev) 195 { 196 struct sock *child = NULL; 197 198 /* Check for retransmitted REQUEST */ 199 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 200 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, 201 dccp_rsk(req)->dreq_isr)) { 202 struct dccp_request_sock *dreq = dccp_rsk(req); 203 204 dccp_pr_debug("Retransmitted REQUEST\n"); 205 /* Send another RESPONSE packet */ 206 dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1); 207 dccp_set_seqno(&dreq->dreq_isr, 208 DCCP_SKB_CB(skb)->dccpd_seq); 209 req->rsk_ops->rtx_syn_ack(sk, req, NULL); 210 } 211 /* Network Duplicate, discard packet */ 212 return NULL; 213 } 214 215 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 216 217 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 218 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 219 goto drop; 220 221 /* Invalid ACK */ 222 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) { 223 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 224 "dreq_iss=%llu\n", 225 (unsigned long long) 226 DCCP_SKB_CB(skb)->dccpd_ack_seq, 227 (unsigned long long) 228 dccp_rsk(req)->dreq_iss); 229 goto drop; 230 } 231 232 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); 233 if (child == NULL) 234 goto listen_overflow; 235 236 /* FIXME: deal with options */ 237 238 inet_csk_reqsk_queue_unlink(sk, req, prev); 239 inet_csk_reqsk_queue_removed(sk, req); 240 inet_csk_reqsk_queue_add(sk, req, child); 241 out: 242 return child; 243 listen_overflow: 244 dccp_pr_debug("listen_overflow!\n"); 245 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 246 drop: 247 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 248 req->rsk_ops->send_reset(skb); 249 250 inet_csk_reqsk_queue_drop(sk, req, prev); 251 goto out; 252 } 253 254 EXPORT_SYMBOL_GPL(dccp_check_req); 255 256 /* 257 * Queue segment on the new socket if the new socket is active, 258 * otherwise we just shortcircuit this and continue with 259 * the new socket. 260 */ 261 int dccp_child_process(struct sock *parent, struct sock *child, 262 struct sk_buff *skb) 263 { 264 int ret = 0; 265 const int state = child->sk_state; 266 267 if (!sock_owned_by_user(child)) { 268 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 269 skb->len); 270 271 /* Wakeup parent, send SIGIO */ 272 if (state == DCCP_RESPOND && child->sk_state != state) 273 parent->sk_data_ready(parent, 0); 274 } else { 275 /* Alas, it is possible again, because we do lookup 276 * in main socket hash table and lock on listening 277 * socket does not protect us more. 278 */ 279 sk_add_backlog(child, skb); 280 } 281 282 bh_unlock_sock(child); 283 sock_put(child); 284 return ret; 285 } 286 287 EXPORT_SYMBOL_GPL(dccp_child_process); 288