Commit | Line | Data |
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7c657876 ACM |
1 | /* |
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 | ||
19 | #include "ccid.h" | |
20 | #include "dccp.h" | |
21 | ||
22 | static void dccp_fin(struct sock *sk, struct sk_buff *skb) | |
23 | { | |
24 | sk->sk_shutdown |= RCV_SHUTDOWN; | |
25 | sock_set_flag(sk, SOCK_DONE); | |
26 | __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4); | |
27 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
28 | skb_set_owner_r(skb, sk); | |
29 | sk->sk_data_ready(sk, 0); | |
30 | } | |
31 | ||
32 | static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb) | |
33 | { | |
34 | switch (sk->sk_state) { | |
35 | case DCCP_PARTOPEN: | |
36 | case DCCP_OPEN: | |
37 | dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED); | |
38 | dccp_fin(sk, skb); | |
39 | dccp_set_state(sk, DCCP_CLOSED); | |
40 | break; | |
41 | } | |
42 | } | |
43 | ||
44 | static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) | |
45 | { | |
46 | /* | |
47 | * Step 7: Check for unexpected packet types | |
48 | * If (S.is_server and P.type == CloseReq) | |
49 | * Send Sync packet acknowledging P.seqno | |
50 | * Drop packet and return | |
51 | */ | |
52 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { | |
e92ae93a | 53 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 ACM |
54 | return; |
55 | } | |
56 | ||
57 | switch (sk->sk_state) { | |
58 | case DCCP_PARTOPEN: | |
59 | case DCCP_OPEN: | |
60 | dccp_set_state(sk, DCCP_CLOSING); | |
61 | dccp_send_close(sk); | |
62 | break; | |
63 | } | |
64 | } | |
65 | ||
66 | static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb) | |
67 | { | |
68 | struct dccp_sock *dp = dccp_sk(sk); | |
69 | ||
70 | if (dp->dccps_options.dccpo_send_ack_vector) | |
71 | dccp_ackpkts_check_rcv_ackno(dp->dccps_hc_rx_ackpkts, sk, | |
72 | DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
73 | } | |
74 | ||
75 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) | |
76 | { | |
77 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
78 | struct dccp_sock *dp = dccp_sk(sk); | |
e92ae93a | 79 | u64 lswl, lawl; |
7c657876 ACM |
80 | |
81 | /* | |
82 | * Step 5: Prepare sequence numbers for Sync | |
83 | * If P.type == Sync or P.type == SyncAck, | |
84 | * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, | |
85 | * / * P is valid, so update sequence number variables | |
86 | * accordingly. After this update, P will pass the tests | |
87 | * in Step 6. A SyncAck is generated if necessary in | |
88 | * Step 15 * / | |
89 | * Update S.GSR, S.SWL, S.SWH | |
90 | * Otherwise, | |
91 | * Drop packet and return | |
92 | */ | |
93 | if (dh->dccph_type == DCCP_PKT_SYNC || | |
94 | dh->dccph_type == DCCP_PKT_SYNCACK) { | |
7690af3f ACM |
95 | if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
96 | dp->dccps_awl, dp->dccps_awh) && | |
7c657876 ACM |
97 | !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl)) |
98 | dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); | |
99 | else | |
100 | return -1; | |
e92ae93a ACM |
101 | } |
102 | ||
7c657876 ACM |
103 | /* |
104 | * Step 6: Check sequence numbers | |
105 | * Let LSWL = S.SWL and LAWL = S.AWL | |
106 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
107 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
108 | * If LSWL <= P.seqno <= S.SWH | |
109 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
110 | * Update S.GSR, S.SWL, S.SWH | |
111 | * If P.type != Sync, | |
112 | * Update S.GAR | |
113 | * Otherwise, | |
114 | * Send Sync packet acknowledging P.seqno | |
115 | * Drop packet and return | |
116 | */ | |
e92ae93a ACM |
117 | lswl = dp->dccps_swl; |
118 | lawl = dp->dccps_awl; | |
119 | ||
120 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
121 | dh->dccph_type == DCCP_PKT_CLOSE || |
122 | dh->dccph_type == DCCP_PKT_RESET) { | |
7c657876 ACM |
123 | lswl = dp->dccps_gsr; |
124 | dccp_inc_seqno(&lswl); | |
125 | lawl = dp->dccps_gar; | |
126 | } | |
127 | ||
128 | if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) && | |
129 | (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ || | |
7690af3f ACM |
130 | between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
131 | lawl, dp->dccps_awh))) { | |
7c657876 ACM |
132 | dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); |
133 | ||
134 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
7690af3f ACM |
135 | (DCCP_SKB_CB(skb)->dccpd_ack_seq != |
136 | DCCP_PKT_WITHOUT_ACK_SEQ)) | |
7c657876 ACM |
137 | dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq; |
138 | } else { | |
a3054d48 ACM |
139 | LIMIT_NETDEBUG(KERN_WARNING "DCCP: Step 6 failed for %s packet, " |
140 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " | |
141 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
142 | "sending SYNC...\n", | |
143 | dccp_packet_name(dh->dccph_type), | |
144 | lswl, DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swh, | |
145 | (DCCP_SKB_CB(skb)->dccpd_ack_seq == | |
146 | DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists", | |
147 | lawl, DCCP_SKB_CB(skb)->dccpd_ack_seq, dp->dccps_awh); | |
e92ae93a | 148 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 ACM |
149 | return -1; |
150 | } | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, | |
156 | const struct dccp_hdr *dh, const unsigned len) | |
157 | { | |
158 | struct dccp_sock *dp = dccp_sk(sk); | |
159 | ||
160 | if (dccp_check_seqno(sk, skb)) | |
161 | goto discard; | |
162 | ||
163 | if (dccp_parse_options(sk, skb)) | |
164 | goto discard; | |
165 | ||
166 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
167 | dccp_event_ack_recv(sk, skb); | |
168 | ||
169 | /* | |
170 | * FIXME: check ECN to see if we should use | |
171 | * DCCP_ACKPKTS_STATE_ECN_MARKED | |
172 | */ | |
173 | if (dp->dccps_options.dccpo_send_ack_vector) { | |
174 | struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts; | |
175 | ||
176 | if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts, | |
177 | DCCP_SKB_CB(skb)->dccpd_seq, | |
178 | DCCP_ACKPKTS_STATE_RECEIVED)) { | |
c59eab46 ACM |
179 | LIMIT_NETDEBUG(KERN_WARNING "DCCP: acknowledgeable " |
180 | "packets buffer full!\n"); | |
7c657876 ACM |
181 | ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1; |
182 | inet_csk_schedule_ack(sk); | |
7690af3f ACM |
183 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
184 | TCP_DELACK_MIN, | |
185 | DCCP_RTO_MAX); | |
7c657876 ACM |
186 | goto discard; |
187 | } | |
188 | ||
189 | /* | |
190 | * FIXME: this activation is probably wrong, have to study more | |
191 | * TCP delack machinery and how it fits into DCCP draft, but | |
192 | * for now it kinda "works" 8) | |
193 | */ | |
194 | if (!inet_csk_ack_scheduled(sk)) { | |
195 | inet_csk_schedule_ack(sk); | |
7690af3f ACM |
196 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 5 * HZ, |
197 | DCCP_RTO_MAX); | |
7c657876 ACM |
198 | } |
199 | } | |
200 | ||
201 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); | |
202 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
203 | ||
204 | switch (dccp_hdr(skb)->dccph_type) { | |
205 | case DCCP_PKT_DATAACK: | |
206 | case DCCP_PKT_DATA: | |
207 | /* | |
7690af3f ACM |
208 | * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED |
209 | * option if it is. | |
7c657876 ACM |
210 | */ |
211 | __skb_pull(skb, dh->dccph_doff * 4); | |
212 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
213 | skb_set_owner_r(skb, sk); | |
214 | sk->sk_data_ready(sk, 0); | |
215 | return 0; | |
216 | case DCCP_PKT_ACK: | |
217 | goto discard; | |
218 | case DCCP_PKT_RESET: | |
219 | /* | |
220 | * Step 9: Process Reset | |
221 | * If P.type == Reset, | |
222 | * Tear down connection | |
223 | * S.state := TIMEWAIT | |
224 | * Set TIMEWAIT timer | |
225 | * Drop packet and return | |
226 | */ | |
227 | dccp_fin(sk, skb); | |
228 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
229 | return 0; | |
230 | case DCCP_PKT_CLOSEREQ: | |
231 | dccp_rcv_closereq(sk, skb); | |
232 | goto discard; | |
233 | case DCCP_PKT_CLOSE: | |
234 | dccp_rcv_close(sk, skb); | |
235 | return 0; | |
236 | case DCCP_PKT_REQUEST: | |
237 | /* Step 7 | |
238 | * or (S.is_server and P.type == Response) | |
239 | * or (S.is_client and P.type == Request) | |
240 | * or (S.state >= OPEN and P.type == Request | |
241 | * and P.seqno >= S.OSR) | |
242 | * or (S.state >= OPEN and P.type == Response | |
243 | * and P.seqno >= S.OSR) | |
244 | * or (S.state == RESPOND and P.type == Data), | |
245 | * Send Sync packet acknowledging P.seqno | |
246 | * Drop packet and return | |
247 | */ | |
248 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
249 | goto send_sync; | |
250 | goto check_seq; | |
251 | case DCCP_PKT_RESPONSE: | |
252 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
253 | goto send_sync; | |
254 | check_seq: | |
255 | if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) { | |
256 | send_sync: | |
e92ae93a ACM |
257 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
258 | DCCP_PKT_SYNC); | |
7c657876 ACM |
259 | } |
260 | break; | |
e92ae93a ACM |
261 | case DCCP_PKT_SYNC: |
262 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
263 | DCCP_PKT_SYNCACK); | |
264 | /* | |
265 | * From the draft: | |
266 | * | |
267 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
268 | * MAY have non-zero-length application data areas, whose | |
269 | * contents * receivers MUST ignore. | |
270 | */ | |
271 | goto discard; | |
7c657876 ACM |
272 | } |
273 | ||
274 | DCCP_INC_STATS_BH(DCCP_MIB_INERRS); | |
275 | discard: | |
276 | __kfree_skb(skb); | |
277 | return 0; | |
278 | } | |
279 | ||
280 | static int dccp_rcv_request_sent_state_process(struct sock *sk, | |
281 | struct sk_buff *skb, | |
282 | const struct dccp_hdr *dh, | |
283 | const unsigned len) | |
284 | { | |
285 | /* | |
286 | * Step 4: Prepare sequence numbers in REQUEST | |
287 | * If S.state == REQUEST, | |
288 | * If (P.type == Response or P.type == Reset) | |
289 | * and S.AWL <= P.ackno <= S.AWH, | |
290 | * / * Set sequence number variables corresponding to the | |
291 | * other endpoint, so P will pass the tests in Step 6 * / | |
292 | * Set S.GSR, S.ISR, S.SWL, S.SWH | |
293 | * / * Response processing continues in Step 10; Reset | |
294 | * processing continues in Step 9 * / | |
295 | */ | |
296 | if (dh->dccph_type == DCCP_PKT_RESPONSE) { | |
297 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
298 | struct dccp_sock *dp = dccp_sk(sk); | |
299 | ||
300 | /* Stop the REQUEST timer */ | |
301 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
302 | BUG_TRAP(sk->sk_send_head != NULL); | |
303 | __kfree_skb(sk->sk_send_head); | |
304 | sk->sk_send_head = NULL; | |
305 | ||
7690af3f ACM |
306 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
307 | dp->dccps_awl, dp->dccps_awh)) { | |
308 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
309 | "P.ackno=%llu, S.AWH=%llu \n", | |
310 | (unsigned long long)dp->dccps_awl, | |
311 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
312 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
313 | goto out_invalid_packet; |
314 | } | |
315 | ||
316 | dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; | |
03ace394 ACM |
317 | dccp_update_gsr(sk, dp->dccps_isr); |
318 | /* | |
319 | * SWL and AWL are initially adjusted so that they are not less than | |
320 | * the initial Sequence Numbers received and sent, respectively: | |
321 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
322 | * AWL := max(GSS - W' + 1, ISS). | |
323 | * These adjustments MUST be applied only at the beginning of the | |
324 | * connection. | |
325 | * | |
326 | * AWL was adjusted in dccp_v4_connect -acme | |
327 | */ | |
328 | dccp_set_seqno(&dp->dccps_swl, | |
329 | max48(dp->dccps_swl, dp->dccps_isr)); | |
7c657876 ACM |
330 | |
331 | if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 || | |
332 | ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) { | |
333 | ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk); | |
334 | ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk); | |
335 | /* FIXME: send appropriate RESET code */ | |
336 | goto out_invalid_packet; | |
337 | } | |
338 | ||
339 | dccp_sync_mss(sk, dp->dccps_pmtu_cookie); | |
340 | ||
341 | /* | |
342 | * Step 10: Process REQUEST state (second part) | |
343 | * If S.state == REQUEST, | |
7690af3f ACM |
344 | * / * If we get here, P is a valid Response from the |
345 | * server (see Step 4), and we should move to | |
346 | * PARTOPEN state. PARTOPEN means send an Ack, | |
347 | * don't send Data packets, retransmit Acks | |
348 | * periodically, and always include any Init Cookie | |
349 | * from the Response * / | |
7c657876 ACM |
350 | * S.state := PARTOPEN |
351 | * Set PARTOPEN timer | |
352 | * Continue with S.state == PARTOPEN | |
7690af3f ACM |
353 | * / * Step 12 will send the Ack completing the |
354 | * three-way handshake * / | |
7c657876 ACM |
355 | */ |
356 | dccp_set_state(sk, DCCP_PARTOPEN); | |
357 | ||
358 | /* Make sure socket is routed, for correct metrics. */ | |
359 | inet_sk_rebuild_header(sk); | |
360 | ||
361 | if (!sock_flag(sk, SOCK_DEAD)) { | |
362 | sk->sk_state_change(sk); | |
363 | sk_wake_async(sk, 0, POLL_OUT); | |
364 | } | |
365 | ||
366 | if (sk->sk_write_pending || icsk->icsk_ack.pingpong || | |
367 | icsk->icsk_accept_queue.rskq_defer_accept) { | |
368 | /* Save one ACK. Data will be ready after | |
369 | * several ticks, if write_pending is set. | |
370 | * | |
371 | * It may be deleted, but with this feature tcpdumps | |
372 | * look so _wonderfully_ clever, that I was not able | |
373 | * to stand against the temptation 8) --ANK | |
374 | */ | |
375 | /* | |
376 | * OK, in DCCP we can as well do a similar trick, its | |
377 | * even in the draft, but there is no need for us to | |
378 | * schedule an ack here, as dccp_sendmsg does this for | |
379 | * us, also stated in the draft. -acme | |
380 | */ | |
381 | __kfree_skb(skb); | |
382 | return 0; | |
383 | } | |
384 | dccp_send_ack(sk); | |
385 | return -1; | |
386 | } | |
387 | ||
388 | out_invalid_packet: | |
389 | return 1; /* dccp_v4_do_rcv will send a reset, but... | |
7690af3f ACM |
390 | FIXME: the reset code should be |
391 | DCCP_RESET_CODE_PACKET_ERROR */ | |
7c657876 ACM |
392 | } |
393 | ||
394 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
395 | struct sk_buff *skb, | |
396 | const struct dccp_hdr *dh, | |
397 | const unsigned len) | |
398 | { | |
399 | int queued = 0; | |
400 | ||
401 | switch (dh->dccph_type) { | |
402 | case DCCP_PKT_RESET: | |
403 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
404 | break; | |
405 | case DCCP_PKT_DATAACK: | |
406 | case DCCP_PKT_ACK: | |
407 | /* | |
7690af3f ACM |
408 | * FIXME: we should be reseting the PARTOPEN (DELACK) timer |
409 | * here but only if we haven't used the DELACK timer for | |
410 | * something else, like sending a delayed ack for a TIMESTAMP | |
411 | * echo, etc, for now were not clearing it, sending an extra | |
412 | * ACK when there is nothing else to do in DELACK is not a big | |
413 | * deal after all. | |
7c657876 ACM |
414 | */ |
415 | ||
416 | /* Stop the PARTOPEN timer */ | |
417 | if (sk->sk_state == DCCP_PARTOPEN) | |
418 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
419 | ||
420 | dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
421 | dccp_set_state(sk, DCCP_OPEN); | |
422 | ||
423 | if (dh->dccph_type == DCCP_PKT_DATAACK) { | |
424 | dccp_rcv_established(sk, skb, dh, len); | |
7690af3f ACM |
425 | queued = 1; /* packet was queued |
426 | (by dccp_rcv_established) */ | |
7c657876 ACM |
427 | } |
428 | break; | |
429 | } | |
430 | ||
431 | return queued; | |
432 | } | |
433 | ||
434 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
435 | struct dccp_hdr *dh, unsigned len) | |
436 | { | |
437 | struct dccp_sock *dp = dccp_sk(sk); | |
438 | const int old_state = sk->sk_state; | |
439 | int queued = 0; | |
440 | ||
8649b0d4 ACM |
441 | /* |
442 | * Step 3: Process LISTEN state | |
443 | * (Continuing from dccp_v4_do_rcv and dccp_v6_do_rcv) | |
444 | * | |
445 | * If S.state == LISTEN, | |
446 | * If P.type == Request or P contains a valid Init Cookie | |
447 | * option, | |
448 | * * Must scan the packet's options to check for an Init | |
449 | * Cookie. Only the Init Cookie is processed here, | |
450 | * however; other options are processed in Step 8. This | |
451 | * scan need only be performed if the endpoint uses Init | |
452 | * Cookies * | |
453 | * * Generate a new socket and switch to that socket * | |
454 | * Set S := new socket for this port pair | |
455 | * S.state = RESPOND | |
456 | * Choose S.ISS (initial seqno) or set from Init Cookie | |
457 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie | |
458 | * Continue with S.state == RESPOND | |
459 | * * A Response packet will be generated in Step 11 * | |
460 | * Otherwise, | |
461 | * Generate Reset(No Connection) unless P.type == Reset | |
462 | * Drop packet and return | |
463 | * | |
464 | * NOTE: the check for the packet types is done in | |
465 | * dccp_rcv_state_process | |
466 | */ | |
467 | if (sk->sk_state == DCCP_LISTEN) { | |
468 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
469 | if (dccp_v4_conn_request(sk, skb) < 0) | |
470 | return 1; | |
471 | ||
472 | /* FIXME: do congestion control initialization */ | |
473 | goto discard; | |
474 | } | |
475 | if (dh->dccph_type == DCCP_PKT_RESET) | |
476 | goto discard; | |
477 | ||
478 | /* Caller (dccp_v4_do_rcv) will send Reset(No Connection)*/ | |
479 | return 1; | |
480 | } | |
481 | ||
482 | if (sk->sk_state != DCCP_REQUESTING) { | |
7c657876 ACM |
483 | 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 | ||
7690af3f ACM |
492 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != |
493 | DCCP_PKT_WITHOUT_ACK_SEQ) | |
7c657876 ACM |
494 | dccp_event_ack_recv(sk, skb); |
495 | ||
496 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); | |
497 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
498 | ||
499 | /* | |
500 | * FIXME: check ECN to see if we should use | |
501 | * DCCP_ACKPKTS_STATE_ECN_MARKED | |
502 | */ | |
503 | if (dp->dccps_options.dccpo_send_ack_vector) { | |
504 | if (dccp_ackpkts_add(dp->dccps_hc_rx_ackpkts, | |
505 | DCCP_SKB_CB(skb)->dccpd_seq, | |
506 | DCCP_ACKPKTS_STATE_RECEIVED)) | |
507 | goto discard; | |
508 | /* | |
7690af3f ACM |
509 | * FIXME: this activation is probably wrong, have to |
510 | * study more TCP delack machinery and how it fits into | |
511 | * DCCP draft, but for now it kinda "works" 8) | |
7c657876 | 512 | */ |
7690af3f ACM |
513 | if ((dp->dccps_hc_rx_ackpkts->dccpap_ack_seqno == |
514 | DCCP_MAX_SEQNO + 1) && | |
7c657876 ACM |
515 | !inet_csk_ack_scheduled(sk)) { |
516 | inet_csk_schedule_ack(sk); | |
7690af3f ACM |
517 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
518 | TCP_DELACK_MIN, | |
519 | DCCP_RTO_MAX); | |
7c657876 ACM |
520 | } |
521 | } | |
522 | } | |
523 | ||
524 | /* | |
525 | * Step 9: Process Reset | |
526 | * If P.type == Reset, | |
527 | * Tear down connection | |
528 | * S.state := TIMEWAIT | |
529 | * Set TIMEWAIT timer | |
530 | * Drop packet and return | |
531 | */ | |
532 | if (dh->dccph_type == DCCP_PKT_RESET) { | |
7690af3f ACM |
533 | /* |
534 | * Queue the equivalent of TCP fin so that dccp_recvmsg | |
535 | * exits the loop | |
536 | */ | |
7c657876 ACM |
537 | dccp_fin(sk, skb); |
538 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
539 | return 0; | |
540 | /* | |
541 | * Step 7: Check for unexpected packet types | |
542 | * If (S.is_server and P.type == CloseReq) | |
543 | * or (S.is_server and P.type == Response) | |
544 | * or (S.is_client and P.type == Request) | |
545 | * or (S.state == RESPOND and P.type == Data), | |
546 | * Send Sync packet acknowledging P.seqno | |
547 | * Drop packet and return | |
548 | */ | |
549 | } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
7690af3f ACM |
550 | (dh->dccph_type == DCCP_PKT_RESPONSE || |
551 | dh->dccph_type == DCCP_PKT_CLOSEREQ)) || | |
7c657876 ACM |
552 | (dp->dccps_role == DCCP_ROLE_CLIENT && |
553 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
7690af3f ACM |
554 | (sk->sk_state == DCCP_RESPOND && |
555 | dh->dccph_type == DCCP_PKT_DATA)) { | |
e92ae93a ACM |
556 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
557 | DCCP_PKT_SYNC); | |
7c657876 ACM |
558 | goto discard; |
559 | } | |
560 | ||
561 | switch (sk->sk_state) { | |
562 | case DCCP_CLOSED: | |
563 | return 1; | |
564 | ||
7c657876 ACM |
565 | case DCCP_REQUESTING: |
566 | /* FIXME: do congestion control initialization */ | |
567 | ||
568 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); | |
569 | if (queued >= 0) | |
570 | return queued; | |
571 | ||
572 | __kfree_skb(skb); | |
573 | return 0; | |
574 | ||
575 | case DCCP_RESPOND: | |
576 | case DCCP_PARTOPEN: | |
7690af3f ACM |
577 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
578 | dh, len); | |
7c657876 ACM |
579 | break; |
580 | } | |
581 | ||
7690af3f ACM |
582 | if (dh->dccph_type == DCCP_PKT_ACK || |
583 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
584 | switch (old_state) { |
585 | case DCCP_PARTOPEN: | |
586 | sk->sk_state_change(sk); | |
587 | sk_wake_async(sk, 0, POLL_OUT); | |
588 | break; | |
589 | } | |
590 | } | |
591 | ||
592 | if (!queued) { | |
593 | discard: | |
594 | __kfree_skb(skb); | |
595 | } | |
596 | return 0; | |
597 | } |