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, 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 &dccp_death_row), 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 LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket " 88 "table overflow\n"); 89 } 90 91 dccp_done(sk); 92 } 93 94 struct sock *dccp_create_openreq_child(struct sock *sk, 95 const struct request_sock *req, 96 const struct sk_buff *skb) 97 { 98 /* 99 * Step 3: Process LISTEN state 100 * 101 * (* Generate a new socket and switch to that socket *) 102 * Set S := new socket for this port pair 103 */ 104 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); 105 106 if (newsk != NULL) { 107 const struct dccp_request_sock *dreq = dccp_rsk(req); 108 struct inet_connection_sock *newicsk = inet_csk(sk); 109 struct dccp_sock *newdp = dccp_sk(newsk); 110 struct dccp_minisock *newdmsk = dccp_msk(newsk); 111 112 newdp->dccps_role = DCCP_ROLE_SERVER; 113 newdp->dccps_hc_rx_ackvec = NULL; 114 newdp->dccps_service_list = NULL; 115 newdp->dccps_service = dreq->dreq_service; 116 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 117 do_gettimeofday(&newdp->dccps_epoch); 118 119 if (dccp_feat_clone(sk, newsk)) 120 goto out_free; 121 122 if (newdmsk->dccpms_send_ack_vector) { 123 newdp->dccps_hc_rx_ackvec = 124 dccp_ackvec_alloc(GFP_ATOMIC); 125 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) 126 goto out_free; 127 } 128 129 newdp->dccps_hc_rx_ccid = 130 ccid_hc_rx_new(newdmsk->dccpms_rx_ccid, 131 newsk, GFP_ATOMIC); 132 newdp->dccps_hc_tx_ccid = 133 ccid_hc_tx_new(newdmsk->dccpms_tx_ccid, 134 newsk, GFP_ATOMIC); 135 if (unlikely(newdp->dccps_hc_rx_ccid == NULL || 136 newdp->dccps_hc_tx_ccid == NULL)) { 137 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); 138 ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk); 139 ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk); 140 out_free: 141 /* It is still raw copy of parent, so invalidate 142 * destructor and make plain sk_free() */ 143 newsk->sk_destruct = NULL; 144 sk_free(newsk); 145 return NULL; 146 } 147 148 /* 149 * Step 3: Process LISTEN state 150 * 151 * Choose S.ISS (initial seqno) or set from Init Cookies 152 * Initialize S.GAR := S.ISS 153 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 154 */ 155 156 /* See dccp_v4_conn_request */ 157 newdmsk->dccpms_sequence_window = req->rcv_wnd; 158 159 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr; 160 dccp_update_gsr(newsk, dreq->dreq_isr); 161 162 newdp->dccps_iss = dreq->dreq_iss; 163 dccp_update_gss(newsk, dreq->dreq_iss); 164 165 /* 166 * SWL and AWL are initially adjusted so that they are not less than 167 * the initial Sequence Numbers received and sent, respectively: 168 * SWL := max(GSR + 1 - floor(W/4), ISR), 169 * AWL := max(GSS - W' + 1, ISS). 170 * These adjustments MUST be applied only at the beginning of the 171 * connection. 172 */ 173 dccp_set_seqno(&newdp->dccps_swl, 174 max48(newdp->dccps_swl, newdp->dccps_isr)); 175 dccp_set_seqno(&newdp->dccps_awl, 176 max48(newdp->dccps_awl, newdp->dccps_iss)); 177 178 dccp_init_xmit_timers(newsk); 179 180 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 181 } 182 return newsk; 183 } 184 185 EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 186 187 /* 188 * Process an incoming packet for RESPOND sockets represented 189 * as an request_sock. 190 */ 191 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 192 struct request_sock *req, 193 struct request_sock **prev) 194 { 195 struct sock *child = NULL; 196 197 /* Check for retransmitted REQUEST */ 198 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 199 struct dccp_request_sock *dreq = dccp_rsk(req); 200 201 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) { 202 dccp_pr_debug("Retransmitted REQUEST\n"); 203 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq; 204 /* 205 * Send another RESPONSE packet 206 * To protect against Request floods, increment retrans 207 * counter (backoff, monitored by dccp_response_timer). 208 */ 209 req->retrans++; 210 req->rsk_ops->rtx_syn_ack(sk, req, NULL); 211 } 212 /* Network Duplicate, discard packet */ 213 return NULL; 214 } 215 216 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 217 218 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 219 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 220 goto drop; 221 222 /* Invalid ACK */ 223 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) { 224 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 225 "dreq_iss=%llu\n", 226 (unsigned long long) 227 DCCP_SKB_CB(skb)->dccpd_ack_seq, 228 (unsigned long long) 229 dccp_rsk(req)->dreq_iss); 230 goto drop; 231 } 232 233 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); 234 if (child == NULL) 235 goto listen_overflow; 236 237 /* FIXME: deal with options */ 238 239 inet_csk_reqsk_queue_unlink(sk, req, prev); 240 inet_csk_reqsk_queue_removed(sk, req); 241 inet_csk_reqsk_queue_add(sk, req, child); 242 out: 243 return child; 244 listen_overflow: 245 dccp_pr_debug("listen_overflow!\n"); 246 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 247 drop: 248 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 249 req->rsk_ops->send_reset(skb); 250 251 inet_csk_reqsk_queue_drop(sk, req, prev); 252 goto out; 253 } 254 255 EXPORT_SYMBOL_GPL(dccp_check_req); 256 257 /* 258 * Queue segment on the new socket if the new socket is active, 259 * otherwise we just shortcircuit this and continue with 260 * the new socket. 261 */ 262 int dccp_child_process(struct sock *parent, struct sock *child, 263 struct sk_buff *skb) 264 { 265 int ret = 0; 266 const int state = child->sk_state; 267 268 if (!sock_owned_by_user(child)) { 269 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 270 skb->len); 271 272 /* Wakeup parent, send SIGIO */ 273 if (state == DCCP_RESPOND && child->sk_state != state) 274 parent->sk_data_ready(parent, 0); 275 } else { 276 /* Alas, it is possible again, because we do lookup 277 * in main socket hash table and lock on listening 278 * socket does not protect us more. 279 */ 280 sk_add_backlog(child, skb); 281 } 282 283 bh_unlock_sock(child); 284 sock_put(child); 285 return ret; 286 } 287 288 EXPORT_SYMBOL_GPL(dccp_child_process); 289 290 void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk) 291 { 292 pr_info(KERN_WARNING "DCCP: ACK packets are never sent in " 293 "LISTEN/RESPOND state\n"); 294 dump_stack(); 295 } 296 297 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); 298 299 void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb) 300 { 301 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; 302 inet_rsk(req)->acked = 0; 303 req->rcv_wnd = dccp_feat_default_sequence_window; 304 } 305 306 EXPORT_SYMBOL_GPL(dccp_reqsk_init); 307