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_minisock_init(struct dccp_minisock *dmsk)
47 dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
48 dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
51 void dccp_time_wait(struct sock *sk, int state, int timeo)
53 struct inet_timewait_sock *tw = NULL;
55 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
56 tw = inet_twsk_alloc(sk, state);
59 const struct inet_connection_sock *icsk = inet_csk(sk);
60 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
61 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
62 if (tw->tw_family == PF_INET6) {
63 const struct ipv6_pinfo *np = inet6_sk(sk);
64 struct inet6_timewait_sock *tw6;
66 tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
67 tw6 = inet6_twsk((struct sock *)tw);
68 ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
69 ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
70 tw->tw_ipv6only = np->ipv6only;
73 /* Linkage updates. */
74 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
76 /* Get the TIME_WAIT timeout firing. */
80 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
81 if (state == DCCP_TIME_WAIT)
82 timeo = DCCP_TIMEWAIT_LEN;
84 inet_twsk_schedule(tw, &dccp_death_row, timeo,
88 /* Sorry, if we're out of memory, just CLOSE this
89 * socket up. We've got bigger problems than
90 * non-graceful socket closings.
92 DCCP_WARN("time wait bucket table overflow\n");
98 struct sock *dccp_create_openreq_child(struct sock *sk,
99 const struct request_sock *req,
100 const struct sk_buff *skb)
103 * Step 3: Process LISTEN state
105 * (* Generate a new socket and switch to that socket *)
106 * Set S := new socket for this port pair
108 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
111 struct dccp_request_sock *dreq = dccp_rsk(req);
112 struct inet_connection_sock *newicsk = inet_csk(newsk);
113 struct dccp_sock *newdp = dccp_sk(newsk);
114 struct dccp_minisock *newdmsk = dccp_msk(newsk);
116 newdp->dccps_role = DCCP_ROLE_SERVER;
117 newdp->dccps_hc_rx_ackvec = NULL;
118 newdp->dccps_service_list = NULL;
119 newdp->dccps_service = dreq->dreq_service;
120 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
121 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
122 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
124 INIT_LIST_HEAD(&newdp->dccps_featneg);
126 * Step 3: Process LISTEN state
128 * Choose S.ISS (initial seqno) or set from Init Cookies
129 * Initialize S.GAR := S.ISS
130 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
133 /* See dccp_v4_conn_request */
134 newdmsk->dccpms_sequence_window = req->rcv_wnd;
136 newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
137 dccp_update_gss(newsk, dreq->dreq_iss);
139 newdp->dccps_isr = dreq->dreq_isr;
140 dccp_update_gsr(newsk, dreq->dreq_isr);
143 * SWL and AWL are initially adjusted so that they are not less than
144 * the initial Sequence Numbers received and sent, respectively:
145 * SWL := max(GSR + 1 - floor(W/4), ISR),
146 * AWL := max(GSS - W' + 1, ISS).
147 * These adjustments MUST be applied only at the beginning of the
150 dccp_set_seqno(&newdp->dccps_swl,
151 max48(newdp->dccps_swl, newdp->dccps_isr));
152 dccp_set_seqno(&newdp->dccps_awl,
153 max48(newdp->dccps_awl, newdp->dccps_iss));
156 * Activate features after initialising the sequence numbers,
157 * since CCID initialisation may depend on GSS, ISR, ISS etc.
159 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
160 /* It is still raw copy of parent, so invalidate
161 * destructor and make plain sk_free() */
162 newsk->sk_destruct = NULL;
166 dccp_init_xmit_timers(newsk);
168 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
173 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
176 * Process an incoming packet for RESPOND sockets represented
177 * as an request_sock.
179 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
180 struct request_sock *req,
181 struct request_sock **prev)
183 struct sock *child = NULL;
184 struct dccp_request_sock *dreq = dccp_rsk(req);
186 /* Check for retransmitted REQUEST */
187 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
189 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
190 dccp_pr_debug("Retransmitted REQUEST\n");
191 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
193 * Send another RESPONSE packet
194 * To protect against Request floods, increment retrans
195 * counter (backoff, monitored by dccp_response_timer).
198 req->rsk_ops->rtx_syn_ack(sk, req);
200 /* Network Duplicate, discard packet */
204 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
206 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
207 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
211 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
212 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
215 DCCP_SKB_CB(skb)->dccpd_ack_seq,
216 (unsigned long long) dreq->dreq_iss);
220 if (dccp_parse_options(sk, dreq, skb))
223 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
225 goto listen_overflow;
227 inet_csk_reqsk_queue_unlink(sk, req, prev);
228 inet_csk_reqsk_queue_removed(sk, req);
229 inet_csk_reqsk_queue_add(sk, req, child);
233 dccp_pr_debug("listen_overflow!\n");
234 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
236 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
237 req->rsk_ops->send_reset(sk, skb);
239 inet_csk_reqsk_queue_drop(sk, req, prev);
243 EXPORT_SYMBOL_GPL(dccp_check_req);
246 * Queue segment on the new socket if the new socket is active,
247 * otherwise we just shortcircuit this and continue with
250 int dccp_child_process(struct sock *parent, struct sock *child,
254 const int state = child->sk_state;
256 if (!sock_owned_by_user(child)) {
257 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
260 /* Wakeup parent, send SIGIO */
261 if (state == DCCP_RESPOND && child->sk_state != state)
262 parent->sk_data_ready(parent, 0);
264 /* Alas, it is possible again, because we do lookup
265 * in main socket hash table and lock on listening
266 * socket does not protect us more.
268 sk_add_backlog(child, skb);
271 bh_unlock_sock(child);
276 EXPORT_SYMBOL_GPL(dccp_child_process);
278 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
279 struct request_sock *rsk)
281 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
284 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
286 int dccp_reqsk_init(struct request_sock *req,
287 struct dccp_sock const *dp, struct sk_buff const *skb)
289 struct dccp_request_sock *dreq = dccp_rsk(req);
291 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
292 inet_rsk(req)->acked = 0;
293 req->rcv_wnd = sysctl_dccp_feat_sequence_window;
294 dreq->dreq_timestamp_echo = 0;
296 /* inherit feature negotiation options from listening socket */
297 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
300 EXPORT_SYMBOL_GPL(dccp_reqsk_init);