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 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);
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);
117 if (dccp_feat_clone(sk, newsk))
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))
127 newdp->dccps_hc_rx_ccid =
128 ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
130 newdp->dccps_hc_tx_ccid =
131 ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
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);
139 /* It is still raw copy of parent, so invalidate
140 * destructor and make plain sk_free() */
141 newsk->sk_destruct = NULL;
147 * Step 3: Process LISTEN state
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
154 /* See dccp_v4_conn_request */
155 newdmsk->dccpms_sequence_window = req->rcv_wnd;
157 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
158 dccp_update_gsr(newsk, dreq->dreq_isr);
160 newdp->dccps_iss = dreq->dreq_iss;
161 dccp_update_gss(newsk, dreq->dreq_iss);
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
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));
176 dccp_init_xmit_timers(newsk);
178 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
183 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
186 * Process an incoming packet for RESPOND sockets represented
187 * as an request_sock.
189 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
190 struct request_sock *req,
191 struct request_sock **prev)
193 struct sock *child = NULL;
195 /* Check for retransmitted REQUEST */
196 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
197 struct dccp_request_sock *dreq = dccp_rsk(req);
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;
203 * Send another RESPONSE packet
204 * To protect against Request floods, increment retrans
205 * counter (backoff, monitored by dccp_response_timer).
208 req->rsk_ops->rtx_syn_ack(sk, req, NULL);
210 /* Network Duplicate, discard packet */
214 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
216 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
217 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
221 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
222 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
225 DCCP_SKB_CB(skb)->dccpd_ack_seq,
227 dccp_rsk(req)->dreq_iss);
231 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
233 goto listen_overflow;
235 /* FIXME: deal with options */
237 inet_csk_reqsk_queue_unlink(sk, req, prev);
238 inet_csk_reqsk_queue_removed(sk, req);
239 inet_csk_reqsk_queue_add(sk, req, child);
243 dccp_pr_debug("listen_overflow!\n");
244 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
246 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
247 req->rsk_ops->send_reset(sk, skb);
249 inet_csk_reqsk_queue_drop(sk, req, prev);
253 EXPORT_SYMBOL_GPL(dccp_check_req);
256 * Queue segment on the new socket if the new socket is active,
257 * otherwise we just shortcircuit this and continue with
260 int dccp_child_process(struct sock *parent, struct sock *child,
264 const int state = child->sk_state;
266 if (!sock_owned_by_user(child)) {
267 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
270 /* Wakeup parent, send SIGIO */
271 if (state == DCCP_RESPOND && child->sk_state != state)
272 parent->sk_data_ready(parent, 0);
274 /* Alas, it is possible again, because we do lookup
275 * in main socket hash table and lock on listening
276 * socket does not protect us more.
278 sk_add_backlog(child, skb);
281 bh_unlock_sock(child);
286 EXPORT_SYMBOL_GPL(dccp_child_process);
288 void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
290 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
293 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
295 void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
297 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
298 inet_rsk(req)->acked = 0;
299 req->rcv_wnd = sysctl_dccp_feat_sequence_window;
302 EXPORT_SYMBOL_GPL(dccp_reqsk_init);