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, S.SWL, S.SWH from packet or Init Cookies
125 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
126 dccp_update_gss(newsk, dreq->dreq_iss);
128 newdp->dccps_isr = dreq->dreq_isr;
129 dccp_update_gsr(newsk, dreq->dreq_isr);
132 * SWL and AWL are initially adjusted so that they are not less than
133 * the initial Sequence Numbers received and sent, respectively:
134 * SWL := max(GSR + 1 - floor(W/4), ISR),
135 * AWL := max(GSS - W' + 1, ISS).
136 * These adjustments MUST be applied only at the beginning of the
139 dccp_set_seqno(&newdp->dccps_swl,
140 max48(newdp->dccps_swl, newdp->dccps_isr));
141 dccp_set_seqno(&newdp->dccps_awl,
142 max48(newdp->dccps_awl, newdp->dccps_iss));
145 * Activate features after initialising the sequence numbers,
146 * since CCID initialisation may depend on GSS, ISR, ISS etc.
148 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
149 /* It is still raw copy of parent, so invalidate
150 * destructor and make plain sk_free() */
151 newsk->sk_destruct = NULL;
155 dccp_init_xmit_timers(newsk);
157 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
162 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
165 * Process an incoming packet for RESPOND sockets represented
166 * as an request_sock.
168 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
169 struct request_sock *req,
170 struct request_sock **prev)
172 struct sock *child = NULL;
173 struct dccp_request_sock *dreq = dccp_rsk(req);
175 /* Check for retransmitted REQUEST */
176 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
178 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
179 dccp_pr_debug("Retransmitted REQUEST\n");
180 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
182 * Send another RESPONSE packet
183 * To protect against Request floods, increment retrans
184 * counter (backoff, monitored by dccp_response_timer).
187 req->rsk_ops->rtx_syn_ack(sk, req);
189 /* Network Duplicate, discard packet */
193 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
195 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
196 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
200 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
201 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
204 DCCP_SKB_CB(skb)->dccpd_ack_seq,
205 (unsigned long long) dreq->dreq_iss);
209 if (dccp_parse_options(sk, dreq, skb))
212 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
214 goto listen_overflow;
216 inet_csk_reqsk_queue_unlink(sk, req, prev);
217 inet_csk_reqsk_queue_removed(sk, req);
218 inet_csk_reqsk_queue_add(sk, req, child);
222 dccp_pr_debug("listen_overflow!\n");
223 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
225 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
226 req->rsk_ops->send_reset(sk, skb);
228 inet_csk_reqsk_queue_drop(sk, req, prev);
232 EXPORT_SYMBOL_GPL(dccp_check_req);
235 * Queue segment on the new socket if the new socket is active,
236 * otherwise we just shortcircuit this and continue with
239 int dccp_child_process(struct sock *parent, struct sock *child,
243 const int state = child->sk_state;
245 if (!sock_owned_by_user(child)) {
246 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
249 /* Wakeup parent, send SIGIO */
250 if (state == DCCP_RESPOND && child->sk_state != state)
251 parent->sk_data_ready(parent, 0);
253 /* Alas, it is possible again, because we do lookup
254 * in main socket hash table and lock on listening
255 * socket does not protect us more.
257 sk_add_backlog(child, skb);
260 bh_unlock_sock(child);
265 EXPORT_SYMBOL_GPL(dccp_child_process);
267 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
268 struct request_sock *rsk)
270 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
273 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
275 int dccp_reqsk_init(struct request_sock *req,
276 struct dccp_sock const *dp, struct sk_buff const *skb)
278 struct dccp_request_sock *dreq = dccp_rsk(req);
280 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
281 inet_rsk(req)->loc_port = dccp_hdr(skb)->dccph_dport;
282 inet_rsk(req)->acked = 0;
283 dreq->dreq_timestamp_echo = 0;
285 /* inherit feature negotiation options from listening socket */
286 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
289 EXPORT_SYMBOL_GPL(dccp_reqsk_init);