4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
13 #include <linux/dccp.h>
14 #include <linux/kernel.h>
15 #include <linux/skbuff.h>
16 #include <linux/timer.h>
20 #include <net/inet_timewait_sock.h>
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 */
39 .twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
40 (unsigned long)&dccp_death_row),
43 EXPORT_SYMBOL_GPL(dccp_death_row);
45 void dccp_time_wait(struct sock *sk, int state, int timeo)
47 struct inet_timewait_sock *tw = NULL;
49 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
50 tw = inet_twsk_alloc(sk, state);
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;
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;
67 /* Linkage updates. */
68 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
70 /* Get the TIME_WAIT timeout firing. */
74 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
75 if (state == DCCP_TIME_WAIT)
76 timeo = DCCP_TIMEWAIT_LEN;
78 inet_twsk_schedule(tw, &dccp_death_row, timeo,
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.
86 DCCP_WARN("time wait bucket table overflow\n");
92 struct sock *dccp_create_openreq_child(struct sock *sk,
93 const struct request_sock *req,
94 const struct sk_buff *skb)
97 * Step 3: Process LISTEN state
99 * (* Generate a new socket and switch to that socket *)
100 * Set S := new socket for this port pair
102 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
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);
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;
117 INIT_LIST_HEAD(&newdp->dccps_featneg);
119 * Step 3: Process LISTEN state
121 * Choose S.ISS (initial seqno) or set from Init Cookies
122 * Initialize S.GAR := S.ISS
123 * Set S.ISR, S.GSR from packet (or Init Cookies)
125 * Setting AWL/AWH and SWL/SWH happens as part of the feature
126 * activation below, as these windows all depend on the local
127 * and remote Sequence Window feature values (7.5.2).
129 newdp->dccps_gss = newdp->dccps_iss = dreq->dreq_iss;
130 newdp->dccps_gar = newdp->dccps_iss;
131 newdp->dccps_gsr = newdp->dccps_isr = dreq->dreq_isr;
134 * Activate features: initialise CCIDs, sequence windows etc.
136 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
137 /* It is still raw copy of parent, so invalidate
138 * destructor and make plain sk_free() */
139 newsk->sk_destruct = NULL;
143 dccp_init_xmit_timers(newsk);
145 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
150 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
153 * Process an incoming packet for RESPOND sockets represented
154 * as an request_sock.
156 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
157 struct request_sock *req,
158 struct request_sock **prev)
160 struct sock *child = NULL;
161 struct dccp_request_sock *dreq = dccp_rsk(req);
163 /* Check for retransmitted REQUEST */
164 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
166 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
167 dccp_pr_debug("Retransmitted REQUEST\n");
168 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
170 * Send another RESPONSE packet
171 * To protect against Request floods, increment retrans
172 * counter (backoff, monitored by dccp_response_timer).
175 req->rsk_ops->rtx_syn_ack(sk, req);
177 /* Network Duplicate, discard packet */
181 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
183 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
184 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
188 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
189 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
192 DCCP_SKB_CB(skb)->dccpd_ack_seq,
193 (unsigned long long) dreq->dreq_iss);
197 if (dccp_parse_options(sk, dreq, skb))
200 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
202 goto listen_overflow;
204 inet_csk_reqsk_queue_unlink(sk, req, prev);
205 inet_csk_reqsk_queue_removed(sk, req);
206 inet_csk_reqsk_queue_add(sk, req, child);
210 dccp_pr_debug("listen_overflow!\n");
211 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
213 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
214 req->rsk_ops->send_reset(sk, skb);
216 inet_csk_reqsk_queue_drop(sk, req, prev);
220 EXPORT_SYMBOL_GPL(dccp_check_req);
223 * Queue segment on the new socket if the new socket is active,
224 * otherwise we just shortcircuit this and continue with
227 int dccp_child_process(struct sock *parent, struct sock *child,
231 const int state = child->sk_state;
233 if (!sock_owned_by_user(child)) {
234 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
237 /* Wakeup parent, send SIGIO */
238 if (state == DCCP_RESPOND && child->sk_state != state)
239 parent->sk_data_ready(parent, 0);
241 /* Alas, it is possible again, because we do lookup
242 * in main socket hash table and lock on listening
243 * socket does not protect us more.
245 sk_add_backlog(child, skb);
248 bh_unlock_sock(child);
253 EXPORT_SYMBOL_GPL(dccp_child_process);
255 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
256 struct request_sock *rsk)
258 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
261 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
263 int dccp_reqsk_init(struct request_sock *req,
264 struct dccp_sock const *dp, struct sk_buff const *skb)
266 struct dccp_request_sock *dreq = dccp_rsk(req);
268 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
269 inet_rsk(req)->acked = 0;
270 dreq->dreq_timestamp_echo = 0;
272 /* inherit feature negotiation options from listening socket */
273 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
276 EXPORT_SYMBOL_GPL(dccp_reqsk_init);