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_minisock_init(struct dccp_minisock *dmsk) 46 { 47 dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window; 48 dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid; 49 dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid; 50 dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio; 51 dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector; 52 dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count; 53 } 54 55 void dccp_time_wait(struct sock *sk, int state, int timeo) 56 { 57 struct inet_timewait_sock *tw = NULL; 58 59 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets) 60 tw = inet_twsk_alloc(sk, state); 61 62 if (tw != NULL) { 63 const struct inet_connection_sock *icsk = inet_csk(sk); 64 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); 65 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 66 if (tw->tw_family == PF_INET6) { 67 const struct ipv6_pinfo *np = inet6_sk(sk); 68 struct inet6_timewait_sock *tw6; 69 70 tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot); 71 tw6 = inet6_twsk((struct sock *)tw); 72 ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr); 73 ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr); 74 tw->tw_ipv6only = np->ipv6only; 75 } 76 #endif 77 /* Linkage updates. */ 78 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); 79 80 /* Get the TIME_WAIT timeout firing. */ 81 if (timeo < rto) 82 timeo = rto; 83 84 tw->tw_timeout = DCCP_TIMEWAIT_LEN; 85 if (state == DCCP_TIME_WAIT) 86 timeo = DCCP_TIMEWAIT_LEN; 87 88 inet_twsk_schedule(tw, &dccp_death_row, timeo, 89 DCCP_TIMEWAIT_LEN); 90 inet_twsk_put(tw); 91 } else { 92 /* Sorry, if we're out of memory, just CLOSE this 93 * socket up. We've got bigger problems than 94 * non-graceful socket closings. 95 */ 96 DCCP_WARN("time wait bucket table overflow\n"); 97 } 98 99 dccp_done(sk); 100 } 101 102 struct sock *dccp_create_openreq_child(struct sock *sk, 103 const struct request_sock *req, 104 const struct sk_buff *skb) 105 { 106 /* 107 * Step 3: Process LISTEN state 108 * 109 * (* Generate a new socket and switch to that socket *) 110 * Set S := new socket for this port pair 111 */ 112 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); 113 114 if (newsk != NULL) { 115 const struct dccp_request_sock *dreq = dccp_rsk(req); 116 struct inet_connection_sock *newicsk = inet_csk(newsk); 117 struct dccp_sock *newdp = dccp_sk(newsk); 118 struct dccp_minisock *newdmsk = dccp_msk(newsk); 119 120 newdp->dccps_role = DCCP_ROLE_SERVER; 121 newdp->dccps_hc_rx_ackvec = NULL; 122 newdp->dccps_service_list = NULL; 123 newdp->dccps_service = dreq->dreq_service; 124 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo; 125 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; 126 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 127 128 if (dccp_feat_clone(sk, newsk)) 129 goto out_free; 130 131 if (newdmsk->dccpms_send_ack_vector) { 132 newdp->dccps_hc_rx_ackvec = 133 dccp_ackvec_alloc(GFP_ATOMIC); 134 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) 135 goto out_free; 136 } 137 138 newdp->dccps_hc_rx_ccid = 139 ccid_hc_rx_new(newdmsk->dccpms_rx_ccid, 140 newsk, GFP_ATOMIC); 141 newdp->dccps_hc_tx_ccid = 142 ccid_hc_tx_new(newdmsk->dccpms_tx_ccid, 143 newsk, GFP_ATOMIC); 144 if (unlikely(newdp->dccps_hc_rx_ccid == NULL || 145 newdp->dccps_hc_tx_ccid == NULL)) { 146 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); 147 ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk); 148 ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk); 149 out_free: 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 } 156 157 /* 158 * Step 3: Process LISTEN state 159 * 160 * Choose S.ISS (initial seqno) or set from Init Cookies 161 * Initialize S.GAR := S.ISS 162 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 163 */ 164 165 /* See dccp_v4_conn_request */ 166 newdmsk->dccpms_sequence_window = req->rcv_wnd; 167 168 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss; 169 dccp_update_gss(newsk, dreq->dreq_iss); 170 171 newdp->dccps_isr = dreq->dreq_isr; 172 dccp_update_gsr(newsk, dreq->dreq_isr); 173 174 /* 175 * SWL and AWL are initially adjusted so that they are not less than 176 * the initial Sequence Numbers received and sent, respectively: 177 * SWL := max(GSR + 1 - floor(W/4), ISR), 178 * AWL := max(GSS - W' + 1, ISS). 179 * These adjustments MUST be applied only at the beginning of the 180 * connection. 181 */ 182 dccp_set_seqno(&newdp->dccps_swl, 183 max48(newdp->dccps_swl, newdp->dccps_isr)); 184 dccp_set_seqno(&newdp->dccps_awl, 185 max48(newdp->dccps_awl, newdp->dccps_iss)); 186 187 dccp_init_xmit_timers(newsk); 188 189 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 190 } 191 return newsk; 192 } 193 194 EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 195 196 /* 197 * Process an incoming packet for RESPOND sockets represented 198 * as an request_sock. 199 */ 200 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 201 struct request_sock *req, 202 struct request_sock **prev) 203 { 204 struct sock *child = NULL; 205 struct dccp_request_sock *dreq = dccp_rsk(req); 206 207 /* Check for retransmitted REQUEST */ 208 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 209 210 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) { 211 dccp_pr_debug("Retransmitted REQUEST\n"); 212 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq; 213 /* 214 * Send another RESPONSE packet 215 * To protect against Request floods, increment retrans 216 * counter (backoff, monitored by dccp_response_timer). 217 */ 218 req->retrans++; 219 req->rsk_ops->rtx_syn_ack(sk, req); 220 } 221 /* Network Duplicate, discard packet */ 222 return NULL; 223 } 224 225 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 226 227 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 228 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 229 goto drop; 230 231 /* Invalid ACK */ 232 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) { 233 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 234 "dreq_iss=%llu\n", 235 (unsigned long long) 236 DCCP_SKB_CB(skb)->dccpd_ack_seq, 237 (unsigned long long) dreq->dreq_iss); 238 goto drop; 239 } 240 241 if (dccp_parse_options(sk, dreq, skb)) 242 goto drop; 243 244 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); 245 if (child == NULL) 246 goto listen_overflow; 247 248 inet_csk_reqsk_queue_unlink(sk, req, prev); 249 inet_csk_reqsk_queue_removed(sk, req); 250 inet_csk_reqsk_queue_add(sk, req, child); 251 out: 252 return child; 253 listen_overflow: 254 dccp_pr_debug("listen_overflow!\n"); 255 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 256 drop: 257 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 258 req->rsk_ops->send_reset(sk, skb); 259 260 inet_csk_reqsk_queue_drop(sk, req, prev); 261 goto out; 262 } 263 264 EXPORT_SYMBOL_GPL(dccp_check_req); 265 266 /* 267 * Queue segment on the new socket if the new socket is active, 268 * otherwise we just shortcircuit this and continue with 269 * the new socket. 270 */ 271 int dccp_child_process(struct sock *parent, struct sock *child, 272 struct sk_buff *skb) 273 { 274 int ret = 0; 275 const int state = child->sk_state; 276 277 if (!sock_owned_by_user(child)) { 278 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 279 skb->len); 280 281 /* Wakeup parent, send SIGIO */ 282 if (state == DCCP_RESPOND && child->sk_state != state) 283 parent->sk_data_ready(parent, 0); 284 } else { 285 /* Alas, it is possible again, because we do lookup 286 * in main socket hash table and lock on listening 287 * socket does not protect us more. 288 */ 289 sk_add_backlog(child, skb); 290 } 291 292 bh_unlock_sock(child); 293 sock_put(child); 294 return ret; 295 } 296 297 EXPORT_SYMBOL_GPL(dccp_child_process); 298 299 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 300 struct request_sock *rsk) 301 { 302 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); 303 } 304 305 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); 306 307 void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb) 308 { 309 struct dccp_request_sock *dreq = dccp_rsk(req); 310 311 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; 312 inet_rsk(req)->loc_port = dccp_hdr(skb)->dccph_dport; 313 inet_rsk(req)->acked = 0; 314 req->rcv_wnd = sysctl_dccp_feat_sequence_window; 315 dreq->dreq_timestamp_echo = 0; 316 } 317 318 EXPORT_SYMBOL_GPL(dccp_reqsk_init); 319