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,
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,
37 /* Short-time timewait calendar */
40 .twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
41 (unsigned long)&dccp_death_row),
44 EXPORT_SYMBOL_GPL(dccp_death_row);
46 void dccp_time_wait(struct sock *sk, int state, int timeo)
48 struct inet_timewait_sock *tw = NULL;
50 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
51 tw = inet_twsk_alloc(sk, state);
54 const struct inet_connection_sock *icsk = inet_csk(sk);
55 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
56 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
57 if (tw->tw_family == PF_INET6) {
58 const struct ipv6_pinfo *np = inet6_sk(sk);
59 struct inet6_timewait_sock *tw6;
61 tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
62 tw6 = inet6_twsk((struct sock *)tw);
63 ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
64 ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
65 tw->tw_ipv6only = np->ipv6only;
68 /* Linkage updates. */
69 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
71 /* Get the TIME_WAIT timeout firing. */
75 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
76 if (state == DCCP_TIME_WAIT)
77 timeo = DCCP_TIMEWAIT_LEN;
79 inet_twsk_schedule(tw, &dccp_death_row, timeo,
83 /* Sorry, if we're out of memory, just CLOSE this
84 * socket up. We've got bigger problems than
85 * non-graceful socket closings.
87 LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket "
94 struct sock *dccp_create_openreq_child(struct sock *sk,
95 const struct request_sock *req,
96 const struct sk_buff *skb)
99 * Step 3: Process LISTEN state
101 * (* Generate a new socket and switch to that socket *)
102 * Set S := new socket for this port pair
104 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
107 const struct dccp_request_sock *dreq = dccp_rsk(req);
108 struct inet_connection_sock *newicsk = inet_csk(sk);
109 struct dccp_sock *newdp = dccp_sk(newsk);
110 struct dccp_minisock *newdmsk = dccp_msk(newsk);
112 newdp->dccps_role = DCCP_ROLE_SERVER;
113 newdp->dccps_hc_rx_ackvec = NULL;
114 newdp->dccps_service_list = NULL;
115 newdp->dccps_service = dreq->dreq_service;
116 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
117 do_gettimeofday(&newdp->dccps_epoch);
119 if (dccp_feat_clone(sk, newsk))
122 if (newdmsk->dccpms_send_ack_vector) {
123 newdp->dccps_hc_rx_ackvec =
124 dccp_ackvec_alloc(GFP_ATOMIC);
125 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
129 newdp->dccps_hc_rx_ccid =
130 ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
132 newdp->dccps_hc_tx_ccid =
133 ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
135 if (unlikely(newdp->dccps_hc_rx_ccid == NULL ||
136 newdp->dccps_hc_tx_ccid == NULL)) {
137 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
138 ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
139 ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
141 /* It is still raw copy of parent, so invalidate
142 * destructor and make plain sk_free() */
143 newsk->sk_destruct = NULL;
149 * Step 3: Process LISTEN state
151 * Choose S.ISS (initial seqno) or set from Init Cookies
152 * Initialize S.GAR := S.ISS
153 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
156 /* See dccp_v4_conn_request */
157 newdmsk->dccpms_sequence_window = req->rcv_wnd;
159 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
160 dccp_update_gsr(newsk, dreq->dreq_isr);
162 newdp->dccps_iss = dreq->dreq_iss;
163 dccp_update_gss(newsk, dreq->dreq_iss);
166 * SWL and AWL are initially adjusted so that they are not less than
167 * the initial Sequence Numbers received and sent, respectively:
168 * SWL := max(GSR + 1 - floor(W/4), ISR),
169 * AWL := max(GSS - W' + 1, ISS).
170 * These adjustments MUST be applied only at the beginning of the
173 dccp_set_seqno(&newdp->dccps_swl,
174 max48(newdp->dccps_swl, newdp->dccps_isr));
175 dccp_set_seqno(&newdp->dccps_awl,
176 max48(newdp->dccps_awl, newdp->dccps_iss));
178 dccp_init_xmit_timers(newsk);
180 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
185 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
188 * Process an incoming packet for RESPOND sockets represented
189 * as an request_sock.
191 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
192 struct request_sock *req,
193 struct request_sock **prev)
195 struct sock *child = NULL;
197 /* Check for retransmitted REQUEST */
198 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
199 struct dccp_request_sock *dreq = dccp_rsk(req);
201 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
202 dccp_pr_debug("Retransmitted REQUEST\n");
203 dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
205 * Send another RESPONSE packet
206 * To protect against Request floods, increment retrans
207 * counter (backoff, monitored by dccp_response_timer).
210 req->rsk_ops->rtx_syn_ack(sk, req, NULL);
212 /* Network Duplicate, discard packet */
216 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
218 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
219 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
223 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
224 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
227 DCCP_SKB_CB(skb)->dccpd_ack_seq,
229 dccp_rsk(req)->dreq_iss);
233 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
235 goto listen_overflow;
237 /* FIXME: deal with options */
239 inet_csk_reqsk_queue_unlink(sk, req, prev);
240 inet_csk_reqsk_queue_removed(sk, req);
241 inet_csk_reqsk_queue_add(sk, req, child);
245 dccp_pr_debug("listen_overflow!\n");
246 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
248 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
249 req->rsk_ops->send_reset(skb);
251 inet_csk_reqsk_queue_drop(sk, req, prev);
255 EXPORT_SYMBOL_GPL(dccp_check_req);
258 * Queue segment on the new socket if the new socket is active,
259 * otherwise we just shortcircuit this and continue with
262 int dccp_child_process(struct sock *parent, struct sock *child,
266 const int state = child->sk_state;
268 if (!sock_owned_by_user(child)) {
269 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
272 /* Wakeup parent, send SIGIO */
273 if (state == DCCP_RESPOND && child->sk_state != state)
274 parent->sk_data_ready(parent, 0);
276 /* Alas, it is possible again, because we do lookup
277 * in main socket hash table and lock on listening
278 * socket does not protect us more.
280 sk_add_backlog(child, skb);
283 bh_unlock_sock(child);
288 EXPORT_SYMBOL_GPL(dccp_child_process);
290 void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
292 pr_info(KERN_WARNING "DCCP: ACK packets are never sent in "
293 "LISTEN/RESPOND state\n");
297 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
299 void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
301 inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
302 inet_rsk(req)->acked = 0;
303 req->rcv_wnd = sysctl_dccp_feat_sequence_window;
306 EXPORT_SYMBOL_GPL(dccp_reqsk_init);