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 27struct 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 43EXPORT_SYMBOL_GPL(dccp_death_row); 44 45void 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 92struct 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 const 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 struct dccp_minisock *newdmsk = dccp_msk(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 (dccp_feat_clone(sk, newsk)) 118 goto out_free; 119 120 if (newdmsk->dccpms_send_ack_vector) { 121 newdp->dccps_hc_rx_ackvec = 122 dccp_ackvec_alloc(GFP_ATOMIC); 123 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) 124 goto out_free; 125 } 126 127 newdp->dccps_hc_rx_ccid = 128 ccid_hc_rx_new(newdmsk->dccpms_rx_ccid, 129 newsk, GFP_ATOMIC); 130 newdp->dccps_hc_tx_ccid = 131 ccid_hc_tx_new(newdmsk->dccpms_tx_ccid, 132 newsk, GFP_ATOMIC); 133 if (unlikely(newdp->dccps_hc_rx_ccid == NULL || 134 newdp->dccps_hc_tx_ccid == NULL)) { 135 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); 136 ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk); 137 ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk); 138out_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 /* 147 * Step 3: Process LISTEN state 148 * 149 * Choose S.ISS (initial seqno) or set from Init Cookies 150 * Initialize S.GAR := S.ISS 151 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies 152 */ 153 154 /* See dccp_v4_conn_request */ 155 newdmsk->dccpms_sequence_window = req->rcv_wnd; 156 157 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr; 158 dccp_update_gsr(newsk, dreq->dreq_isr); 159 160 newdp->dccps_iss = dreq->dreq_iss; 161 dccp_update_gss(newsk, dreq->dreq_iss); 162 163 /* 164 * SWL and AWL are initially adjusted so that they are not less than 165 * the initial Sequence Numbers received and sent, respectively: 166 * SWL := max(GSR + 1 - floor(W/4), ISR), 167 * AWL := max(GSS - W' + 1, ISS). 168 * These adjustments MUST be applied only at the beginning of the 169 * connection. 170 */ 171 dccp_set_seqno(&newdp->dccps_swl, 172 max48(newdp->dccps_swl, newdp->dccps_isr)); 173 dccp_set_seqno(&newdp->dccps_awl, 174 max48(newdp->dccps_awl, newdp->dccps_iss)); 175 176 dccp_init_xmit_timers(newsk); 177 178 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 179 } 180 return newsk; 181} 182 183EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 184 185/* 186 * Process an incoming packet for RESPOND sockets represented 187 * as an request_sock. 188 */ 189struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 190 struct request_sock *req, 191 struct request_sock **prev) 192{ 193 struct sock *child = NULL; 194 195 /* Check for retransmitted REQUEST */ 196 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 197 struct dccp_request_sock *dreq = dccp_rsk(req); 198 199 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) { 200 dccp_pr_debug("Retransmitted REQUEST\n"); 201 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq; 202 /* 203 * Send another RESPONSE packet 204 * To protect against Request floods, increment retrans 205 * counter (backoff, monitored by dccp_response_timer). 206 */ 207 req->retrans++; 208 req->rsk_ops->rtx_syn_ack(sk, req, NULL); 209 } 210 /* Network Duplicate, discard packet */ 211 return NULL; 212 } 213 214 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 215 216 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 217 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 218 goto drop; 219 220 /* Invalid ACK */ 221 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) { 222 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 223 "dreq_iss=%llu\n", 224 (unsigned long long) 225 DCCP_SKB_CB(skb)->dccpd_ack_seq, 226 (unsigned long long) 227 dccp_rsk(req)->dreq_iss); 228 goto drop; 229 } 230 231 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); 232 if (child == NULL) 233 goto listen_overflow; 234 235 236 inet_csk_reqsk_queue_unlink(sk, req, prev); 237 inet_csk_reqsk_queue_removed(sk, req); 238 inet_csk_reqsk_queue_add(sk, req, child); 239out: 240 return child; 241listen_overflow: 242 dccp_pr_debug("listen_overflow!\n"); 243 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 244drop: 245 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 246 req->rsk_ops->send_reset(sk, skb); 247 248 inet_csk_reqsk_queue_drop(sk, req, prev); 249 goto out; 250} 251 252EXPORT_SYMBOL_GPL(dccp_check_req); 253 254/* 255 * Queue segment on the new socket if the new socket is active, 256 * otherwise we just shortcircuit this and continue with 257 * the new socket. 258 */ 259int dccp_child_process(struct sock *parent, struct sock *child, 260 struct sk_buff *skb) 261{ 262 int ret = 0; 263 const int state = child->sk_state; 264 265 if (!sock_owned_by_user(child)) { 266 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 267 skb->len); 268 269 /* Wakeup parent, send SIGIO */ 270 if (state == DCCP_RESPOND && child->sk_state != state) 271 parent->sk_data_ready(parent, 0); 272 } else { 273 /* Alas, it is possible again, because we do lookup 274 * in main socket hash table and lock on listening 275 * socket does not protect us more. 276 */ 277 sk_add_backlog(child, skb); 278 } 279 280 bh_unlock_sock(child); 281 sock_put(child); 282 return ret; 283} 284 285EXPORT_SYMBOL_GPL(dccp_child_process); 286 287void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk) 288{ 289 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); 290} 291 292EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); 293 294void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb) 295{ 296 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; 297 inet_rsk(req)->acked = 0; 298 req->rcv_wnd = sysctl_dccp_feat_sequence_window; 299} 300 301EXPORT_SYMBOL_GPL(dccp_reqsk_init); 302