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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/input.c
3 *
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
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.
11 */
12
13#include <linux/config.h>
14#include <linux/dccp.h>
15#include <linux/skbuff.h>
16
17#include <net/sock.h>
18
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070019#include "ackvec.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070020#include "ccid.h"
21#include "dccp.h"
22
23static void dccp_fin(struct sock *sk, struct sk_buff *skb)
24{
25 sk->sk_shutdown |= RCV_SHUTDOWN;
26 sock_set_flag(sk, SOCK_DONE);
27 __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
28 __skb_queue_tail(&sk->sk_receive_queue, skb);
29 skb_set_owner_r(skb, sk);
30 sk->sk_data_ready(sk, 0);
31}
32
33static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
34{
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -070035 dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
36 dccp_fin(sk, skb);
37 dccp_set_state(sk, DCCP_CLOSED);
Arnaldo Carvalho de Melo331968b2005-08-23 21:54:23 -070038 sk_wake_async(sk, 1, POLL_HUP);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070039}
40
41static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
42{
43 /*
44 * Step 7: Check for unexpected packet types
45 * If (S.is_server and P.type == CloseReq)
46 * Send Sync packet acknowledging P.seqno
47 * Drop packet and return
48 */
49 if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -030050 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070051 return;
52 }
53
Arnaldo Carvalho de Melo811265b2005-09-13 19:03:15 -030054 if (sk->sk_state != DCCP_CLOSING)
55 dccp_set_state(sk, DCCP_CLOSING);
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -070056 dccp_send_close(sk, 0);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070057}
58
59static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
60{
61 struct dccp_sock *dp = dccp_sk(sk);
62
63 if (dp->dccps_options.dccpo_send_ack_vector)
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070064 dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
65 DCCP_SKB_CB(skb)->dccpd_ack_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070066}
67
68static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
69{
70 const struct dccp_hdr *dh = dccp_hdr(skb);
71 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -030072 u64 lswl, lawl;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070073
74 /*
75 * Step 5: Prepare sequence numbers for Sync
76 * If P.type == Sync or P.type == SyncAck,
77 * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
78 * / * P is valid, so update sequence number variables
79 * accordingly. After this update, P will pass the tests
80 * in Step 6. A SyncAck is generated if necessary in
81 * Step 15 * /
82 * Update S.GSR, S.SWL, S.SWH
83 * Otherwise,
84 * Drop packet and return
85 */
86 if (dh->dccph_type == DCCP_PKT_SYNC ||
87 dh->dccph_type == DCCP_PKT_SYNCACK) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -030088 if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
89 dp->dccps_awl, dp->dccps_awh) &&
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070090 !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl))
91 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
92 else
93 return -1;
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -030094 }
95
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070096 /*
97 * Step 6: Check sequence numbers
98 * Let LSWL = S.SWL and LAWL = S.AWL
99 * If P.type == CloseReq or P.type == Close or P.type == Reset,
100 * LSWL := S.GSR + 1, LAWL := S.GAR
101 * If LSWL <= P.seqno <= S.SWH
102 * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
103 * Update S.GSR, S.SWL, S.SWH
104 * If P.type != Sync,
105 * Update S.GAR
106 * Otherwise,
107 * Send Sync packet acknowledging P.seqno
108 * Drop packet and return
109 */
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300110 lswl = dp->dccps_swl;
111 lawl = dp->dccps_awl;
112
113 if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
Arnaldo Carvalho de Meloc59eab42005-08-18 21:12:02 -0300114 dh->dccph_type == DCCP_PKT_CLOSE ||
115 dh->dccph_type == DCCP_PKT_RESET) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700116 lswl = dp->dccps_gsr;
117 dccp_inc_seqno(&lswl);
118 lawl = dp->dccps_gar;
119 }
120
121 if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) &&
122 (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ ||
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300123 between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
124 lawl, dp->dccps_awh))) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700125 dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);
126
127 if (dh->dccph_type != DCCP_PKT_SYNC &&
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300128 (DCCP_SKB_CB(skb)->dccpd_ack_seq !=
129 DCCP_PKT_WITHOUT_ACK_SEQ))
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700130 dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;
131 } else {
Arnaldo Carvalho de Meloa3054d42005-08-21 05:35:18 -0300132 LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, "
133 "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
134 "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
135 "sending SYNC...\n",
136 dccp_packet_name(dh->dccph_type),
David S. Miller58e45132005-08-21 23:46:01 -0700137 (unsigned long long) lswl,
138 (unsigned long long)
139 DCCP_SKB_CB(skb)->dccpd_seq,
140 (unsigned long long) dp->dccps_swh,
Arnaldo Carvalho de Meloa3054d42005-08-21 05:35:18 -0300141 (DCCP_SKB_CB(skb)->dccpd_ack_seq ==
142 DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists",
David S. Miller58e45132005-08-21 23:46:01 -0700143 (unsigned long long) lawl,
144 (unsigned long long)
145 DCCP_SKB_CB(skb)->dccpd_ack_seq,
146 (unsigned long long) dp->dccps_awh);
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300147 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700148 return -1;
149 }
150
151 return 0;
152}
153
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800154static inline int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
155 const struct dccp_hdr *dh,
156 const unsigned len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700157{
158 struct dccp_sock *dp = dccp_sk(sk);
159
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700160 switch (dccp_hdr(skb)->dccph_type) {
161 case DCCP_PKT_DATAACK:
162 case DCCP_PKT_DATA:
163 /*
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300164 * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
165 * option if it is.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700166 */
167 __skb_pull(skb, dh->dccph_doff * 4);
168 __skb_queue_tail(&sk->sk_receive_queue, skb);
169 skb_set_owner_r(skb, sk);
170 sk->sk_data_ready(sk, 0);
171 return 0;
172 case DCCP_PKT_ACK:
173 goto discard;
174 case DCCP_PKT_RESET:
175 /*
176 * Step 9: Process Reset
177 * If P.type == Reset,
178 * Tear down connection
179 * S.state := TIMEWAIT
180 * Set TIMEWAIT timer
181 * Drop packet and return
182 */
183 dccp_fin(sk, skb);
184 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
185 return 0;
186 case DCCP_PKT_CLOSEREQ:
187 dccp_rcv_closereq(sk, skb);
188 goto discard;
189 case DCCP_PKT_CLOSE:
190 dccp_rcv_close(sk, skb);
191 return 0;
192 case DCCP_PKT_REQUEST:
193 /* Step 7
194 * or (S.is_server and P.type == Response)
195 * or (S.is_client and P.type == Request)
196 * or (S.state >= OPEN and P.type == Request
197 * and P.seqno >= S.OSR)
198 * or (S.state >= OPEN and P.type == Response
199 * and P.seqno >= S.OSR)
200 * or (S.state == RESPOND and P.type == Data),
201 * Send Sync packet acknowledging P.seqno
202 * Drop packet and return
203 */
204 if (dp->dccps_role != DCCP_ROLE_LISTEN)
205 goto send_sync;
206 goto check_seq;
207 case DCCP_PKT_RESPONSE:
208 if (dp->dccps_role != DCCP_ROLE_CLIENT)
209 goto send_sync;
210check_seq:
211 if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {
212send_sync:
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300213 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
214 DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700215 }
216 break;
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300217 case DCCP_PKT_SYNC:
218 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
219 DCCP_PKT_SYNCACK);
220 /*
221 * From the draft:
222 *
223 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
224 * MAY have non-zero-length application data areas, whose
225 * contents * receivers MUST ignore.
226 */
227 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700228 }
229
230 DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
231discard:
232 __kfree_skb(skb);
233 return 0;
234}
235
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800236int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
237 const struct dccp_hdr *dh, const unsigned len)
238{
239 struct dccp_sock *dp = dccp_sk(sk);
240
241 if (dccp_check_seqno(sk, skb))
242 goto discard;
243
244 if (dccp_parse_options(sk, skb))
245 goto discard;
246
247 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
248 dccp_event_ack_recv(sk, skb);
249
250 if (dp->dccps_options.dccpo_send_ack_vector &&
251 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
252 DCCP_SKB_CB(skb)->dccpd_seq,
253 DCCP_ACKVEC_STATE_RECEIVED))
254 goto discard;
255
256 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
257 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
258
259 return __dccp_rcv_established(sk, skb, dh, len);
260discard:
261 __kfree_skb(skb);
262 return 0;
263}
264
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800265EXPORT_SYMBOL_GPL(dccp_rcv_established);
266
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700267static int dccp_rcv_request_sent_state_process(struct sock *sk,
268 struct sk_buff *skb,
269 const struct dccp_hdr *dh,
270 const unsigned len)
271{
272 /*
273 * Step 4: Prepare sequence numbers in REQUEST
274 * If S.state == REQUEST,
275 * If (P.type == Response or P.type == Reset)
276 * and S.AWL <= P.ackno <= S.AWH,
277 * / * Set sequence number variables corresponding to the
278 * other endpoint, so P will pass the tests in Step 6 * /
279 * Set S.GSR, S.ISR, S.SWL, S.SWH
280 * / * Response processing continues in Step 10; Reset
281 * processing continues in Step 9 * /
282 */
283 if (dh->dccph_type == DCCP_PKT_RESPONSE) {
284 const struct inet_connection_sock *icsk = inet_csk(sk);
285 struct dccp_sock *dp = dccp_sk(sk);
286
287 /* Stop the REQUEST timer */
288 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
289 BUG_TRAP(sk->sk_send_head != NULL);
290 __kfree_skb(sk->sk_send_head);
291 sk->sk_send_head = NULL;
292
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300293 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
294 dp->dccps_awl, dp->dccps_awh)) {
295 dccp_pr_debug("invalid ackno: S.AWL=%llu, "
296 "P.ackno=%llu, S.AWH=%llu \n",
297 (unsigned long long)dp->dccps_awl,
298 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
299 (unsigned long long)dp->dccps_awh);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700300 goto out_invalid_packet;
301 }
302
Andrea Bittau9e377202006-01-03 14:25:49 -0800303 if (dp->dccps_options.dccpo_send_ack_vector &&
304 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
305 DCCP_SKB_CB(skb)->dccpd_seq,
306 DCCP_ACKVEC_STATE_RECEIVED))
307 goto out_invalid_packet; /* FIXME: change error code */
308
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700309 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
Arnaldo Carvalho de Melo03ace392005-08-21 05:36:45 -0300310 dccp_update_gsr(sk, dp->dccps_isr);
311 /*
312 * SWL and AWL are initially adjusted so that they are not less than
313 * the initial Sequence Numbers received and sent, respectively:
314 * SWL := max(GSR + 1 - floor(W/4), ISR),
315 * AWL := max(GSS - W' + 1, ISS).
316 * These adjustments MUST be applied only at the beginning of the
317 * connection.
318 *
319 * AWL was adjusted in dccp_v4_connect -acme
320 */
321 dccp_set_seqno(&dp->dccps_swl,
322 max48(dp->dccps_swl, dp->dccps_isr));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700323
324 if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
325 ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
326 ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
327 ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
328 /* FIXME: send appropriate RESET code */
329 goto out_invalid_packet;
330 }
331
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800332 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700333
334 /*
335 * Step 10: Process REQUEST state (second part)
336 * If S.state == REQUEST,
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300337 * / * If we get here, P is a valid Response from the
338 * server (see Step 4), and we should move to
339 * PARTOPEN state. PARTOPEN means send an Ack,
340 * don't send Data packets, retransmit Acks
341 * periodically, and always include any Init Cookie
342 * from the Response * /
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700343 * S.state := PARTOPEN
344 * Set PARTOPEN timer
345 * Continue with S.state == PARTOPEN
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300346 * / * Step 12 will send the Ack completing the
347 * three-way handshake * /
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700348 */
349 dccp_set_state(sk, DCCP_PARTOPEN);
350
351 /* Make sure socket is routed, for correct metrics. */
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800352 icsk->icsk_af_ops->rebuild_header(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700353
354 if (!sock_flag(sk, SOCK_DEAD)) {
355 sk->sk_state_change(sk);
356 sk_wake_async(sk, 0, POLL_OUT);
357 }
358
359 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
360 icsk->icsk_accept_queue.rskq_defer_accept) {
361 /* Save one ACK. Data will be ready after
362 * several ticks, if write_pending is set.
363 *
364 * It may be deleted, but with this feature tcpdumps
365 * look so _wonderfully_ clever, that I was not able
366 * to stand against the temptation 8) --ANK
367 */
368 /*
369 * OK, in DCCP we can as well do a similar trick, its
370 * even in the draft, but there is no need for us to
371 * schedule an ack here, as dccp_sendmsg does this for
372 * us, also stated in the draft. -acme
373 */
374 __kfree_skb(skb);
375 return 0;
376 }
377 dccp_send_ack(sk);
378 return -1;
379 }
380
381out_invalid_packet:
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700382 /* dccp_v4_do_rcv will send a reset */
383 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
384 return 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700385}
386
387static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
388 struct sk_buff *skb,
389 const struct dccp_hdr *dh,
390 const unsigned len)
391{
392 int queued = 0;
393
394 switch (dh->dccph_type) {
395 case DCCP_PKT_RESET:
396 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
397 break;
Arnaldo Carvalho de Melo2a9bc9b2005-10-10 21:25:00 -0700398 case DCCP_PKT_DATA:
399 if (sk->sk_state == DCCP_RESPOND)
400 break;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700401 case DCCP_PKT_DATAACK:
402 case DCCP_PKT_ACK:
403 /*
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300404 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
405 * here but only if we haven't used the DELACK timer for
406 * something else, like sending a delayed ack for a TIMESTAMP
407 * echo, etc, for now were not clearing it, sending an extra
408 * ACK when there is nothing else to do in DELACK is not a big
409 * deal after all.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700410 */
411
412 /* Stop the PARTOPEN timer */
413 if (sk->sk_state == DCCP_PARTOPEN)
414 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
415
416 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
417 dccp_set_state(sk, DCCP_OPEN);
418
Arnaldo Carvalho de Melo2a9bc9b2005-10-10 21:25:00 -0700419 if (dh->dccph_type == DCCP_PKT_DATAACK ||
420 dh->dccph_type == DCCP_PKT_DATA) {
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800421 __dccp_rcv_established(sk, skb, dh, len);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300422 queued = 1; /* packet was queued
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800423 (by __dccp_rcv_established) */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700424 }
425 break;
426 }
427
428 return queued;
429}
430
431int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
432 struct dccp_hdr *dh, unsigned len)
433{
434 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700435 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700436 const int old_state = sk->sk_state;
437 int queued = 0;
438
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300439 /*
440 * Step 3: Process LISTEN state
441 * (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv)
442 *
443 * If S.state == LISTEN,
444 * If P.type == Request or P contains a valid Init Cookie
445 * option,
446 * * Must scan the packet's options to check for an Init
447 * Cookie. Only the Init Cookie is processed here,
448 * however; other options are processed in Step 8. This
449 * scan need only be performed if the endpoint uses Init
450 * Cookies *
451 * * Generate a new socket and switch to that socket *
452 * Set S := new socket for this port pair
453 * S.state = RESPOND
454 * Choose S.ISS (initial seqno) or set from Init Cookie
455 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
456 * Continue with S.state == RESPOND
457 * * A Response packet will be generated in Step 11 *
458 * Otherwise,
459 * Generate Reset(No Connection) unless P.type == Reset
460 * Drop packet and return
461 *
462 * NOTE: the check for the packet types is done in
463 * dccp_rcv_state_process
464 */
465 if (sk->sk_state == DCCP_LISTEN) {
466 if (dh->dccph_type == DCCP_PKT_REQUEST) {
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800467 if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
468 skb) < 0)
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300469 return 1;
470
471 /* FIXME: do congestion control initialization */
472 goto discard;
473 }
474 if (dh->dccph_type == DCCP_PKT_RESET)
475 goto discard;
476
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700477 /* Caller (dccp_v4_do_rcv) will send Reset */
478 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300479 return 1;
480 }
481
482 if (sk->sk_state != DCCP_REQUESTING) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700483 if (dccp_check_seqno(sk, skb))
484 goto discard;
485
486 /*
487 * Step 8: Process options and mark acknowledgeable
488 */
489 if (dccp_parse_options(sk, skb))
490 goto discard;
491
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700492 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700493 dccp_event_ack_recv(sk, skb);
494
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700495 if (dp->dccps_options.dccpo_send_ack_vector &&
496 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
497 DCCP_SKB_CB(skb)->dccpd_seq,
498 DCCP_ACKVEC_STATE_RECEIVED))
499 goto discard;
Andrea Bittaue84a9f52006-01-03 14:26:15 -0800500
501 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
502 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700503 }
504
505 /*
506 * Step 9: Process Reset
507 * If P.type == Reset,
508 * Tear down connection
509 * S.state := TIMEWAIT
510 * Set TIMEWAIT timer
511 * Drop packet and return
512 */
513 if (dh->dccph_type == DCCP_PKT_RESET) {
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300514 /*
515 * Queue the equivalent of TCP fin so that dccp_recvmsg
516 * exits the loop
517 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700518 dccp_fin(sk, skb);
519 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
520 return 0;
521 /*
522 * Step 7: Check for unexpected packet types
523 * If (S.is_server and P.type == CloseReq)
524 * or (S.is_server and P.type == Response)
525 * or (S.is_client and P.type == Request)
526 * or (S.state == RESPOND and P.type == Data),
527 * Send Sync packet acknowledging P.seqno
528 * Drop packet and return
529 */
530 } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300531 (dh->dccph_type == DCCP_PKT_RESPONSE ||
532 dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700533 (dp->dccps_role == DCCP_ROLE_CLIENT &&
534 dh->dccph_type == DCCP_PKT_REQUEST) ||
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300535 (sk->sk_state == DCCP_RESPOND &&
536 dh->dccph_type == DCCP_PKT_DATA)) {
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700537 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700538 goto discard;
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700539 } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
540 dccp_rcv_closereq(sk, skb);
541 goto discard;
542 } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
543 dccp_rcv_close(sk, skb);
544 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700545 }
546
Arnaldo Carvalho de Melo2b802302005-09-13 19:05:08 -0300547 if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700548 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
Arnaldo Carvalho de Melo2b802302005-09-13 19:05:08 -0300549 goto discard;
550 }
551
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700552 switch (sk->sk_state) {
553 case DCCP_CLOSED:
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700554 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700555 return 1;
556
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700557 case DCCP_REQUESTING:
558 /* FIXME: do congestion control initialization */
559
560 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
561 if (queued >= 0)
562 return queued;
563
564 __kfree_skb(skb);
565 return 0;
566
567 case DCCP_RESPOND:
568 case DCCP_PARTOPEN:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300569 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
570 dh, len);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700571 break;
572 }
573
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300574 if (dh->dccph_type == DCCP_PKT_ACK ||
575 dh->dccph_type == DCCP_PKT_DATAACK) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700576 switch (old_state) {
577 case DCCP_PARTOPEN:
578 sk->sk_state_change(sk);
579 sk_wake_async(sk, 0, POLL_OUT);
580 break;
581 }
582 }
583
584 if (!queued) {
585discard:
586 __kfree_skb(skb);
587 }
588 return 0;
589}
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800590
591EXPORT_SYMBOL_GPL(dccp_rcv_state_process);