Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/input.c | |
8109b02b | 3 | * |
7c657876 ACM |
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 | ||
7c657876 ACM |
13 | #include <linux/dccp.h> |
14 | #include <linux/skbuff.h> | |
15 | ||
16 | #include <net/sock.h> | |
17 | ||
ae31c339 | 18 | #include "ackvec.h" |
7c657876 ACM |
19 | #include "ccid.h" |
20 | #include "dccp.h" | |
21 | ||
bd5435e7 IM |
22 | /* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */ |
23 | int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8; | |
24 | ||
7c657876 ACM |
25 | static void dccp_fin(struct sock *sk, struct sk_buff *skb) |
26 | { | |
27 | sk->sk_shutdown |= RCV_SHUTDOWN; | |
28 | sock_set_flag(sk, SOCK_DONE); | |
29 | __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4); | |
30 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
31 | skb_set_owner_r(skb, sk); | |
32 | sk->sk_data_ready(sk, 0); | |
33 | } | |
34 | ||
35 | static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb) | |
36 | { | |
017487d7 | 37 | dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED); |
7ad07e7c ACM |
38 | dccp_fin(sk, skb); |
39 | dccp_set_state(sk, DCCP_CLOSED); | |
331968bd | 40 | sk_wake_async(sk, 1, POLL_HUP); |
7c657876 ACM |
41 | } |
42 | ||
43 | static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) | |
44 | { | |
45 | /* | |
46 | * Step 7: Check for unexpected packet types | |
47 | * If (S.is_server and P.type == CloseReq) | |
48 | * Send Sync packet acknowledging P.seqno | |
49 | * Drop packet and return | |
50 | */ | |
51 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { | |
e92ae93a | 52 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 ACM |
53 | return; |
54 | } | |
55 | ||
811265b8 ACM |
56 | if (sk->sk_state != DCCP_CLOSING) |
57 | dccp_set_state(sk, DCCP_CLOSING); | |
7ad07e7c | 58 | dccp_send_close(sk, 0); |
7c657876 ACM |
59 | } |
60 | ||
c25a18ba | 61 | static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
62 | { |
63 | struct dccp_sock *dp = dccp_sk(sk); | |
64 | ||
a4bf3902 | 65 | if (dccp_msk(sk)->dccpms_send_ack_vector) |
ae31c339 ACM |
66 | dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk, |
67 | DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
7c657876 ACM |
68 | } |
69 | ||
70 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) | |
71 | { | |
72 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
73 | struct dccp_sock *dp = dccp_sk(sk); | |
cbe1f5f8 GR |
74 | u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
75 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
7c657876 ACM |
76 | |
77 | /* | |
78 | * Step 5: Prepare sequence numbers for Sync | |
79 | * If P.type == Sync or P.type == SyncAck, | |
80 | * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, | |
81 | * / * P is valid, so update sequence number variables | |
82 | * accordingly. After this update, P will pass the tests | |
83 | * in Step 6. A SyncAck is generated if necessary in | |
84 | * Step 15 * / | |
85 | * Update S.GSR, S.SWL, S.SWH | |
86 | * Otherwise, | |
87 | * Drop packet and return | |
88 | */ | |
8109b02b | 89 | if (dh->dccph_type == DCCP_PKT_SYNC || |
7c657876 | 90 | dh->dccph_type == DCCP_PKT_SYNCACK) { |
cbe1f5f8 GR |
91 | if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && |
92 | dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) | |
93 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
94 | else |
95 | return -1; | |
e92ae93a | 96 | } |
c9eaf173 | 97 | |
7c657876 ACM |
98 | /* |
99 | * Step 6: Check sequence numbers | |
100 | * Let LSWL = S.SWL and LAWL = S.AWL | |
101 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
102 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
103 | * If LSWL <= P.seqno <= S.SWH | |
104 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
105 | * Update S.GSR, S.SWL, S.SWH | |
106 | * If P.type != Sync, | |
107 | * Update S.GAR | |
7c657876 | 108 | */ |
e92ae93a ACM |
109 | lswl = dp->dccps_swl; |
110 | lawl = dp->dccps_awl; | |
111 | ||
112 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
113 | dh->dccph_type == DCCP_PKT_CLOSE || |
114 | dh->dccph_type == DCCP_PKT_RESET) { | |
cbe1f5f8 | 115 | lswl = ADD48(dp->dccps_gsr, 1); |
7c657876 ACM |
116 | lawl = dp->dccps_gar; |
117 | } | |
118 | ||
cbe1f5f8 GR |
119 | if (between48(seqno, lswl, dp->dccps_swh) && |
120 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || | |
121 | between48(ackno, lawl, dp->dccps_awh))) { | |
122 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
123 | |
124 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
cbe1f5f8 GR |
125 | (ackno != DCCP_PKT_WITHOUT_ACK_SEQ)) |
126 | dp->dccps_gar = ackno; | |
7c657876 | 127 | } else { |
a94f0f97 GR |
128 | unsigned long now = jiffies; |
129 | /* | |
130 | * Step 6: Check sequence numbers | |
131 | * Otherwise, | |
132 | * If P.type == Reset, | |
133 | * Send Sync packet acknowledging S.GSR | |
134 | * Otherwise, | |
135 | * Send Sync packet acknowledging P.seqno | |
136 | * Drop packet and return | |
137 | * | |
138 | * These Syncs are rate-limited as per RFC 4340, 7.5.4: | |
139 | * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. | |
140 | */ | |
141 | if (time_before(now, (dp->dccps_rate_last + | |
142 | sysctl_dccp_sync_ratelimit))) | |
143 | return 0; | |
144 | ||
59348b19 GR |
145 | DCCP_WARN("DCCP: Step 6 failed for %s packet, " |
146 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " | |
147 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
148 | "sending SYNC...\n", dccp_packet_name(dh->dccph_type), | |
cbe1f5f8 | 149 | (unsigned long long) lswl, (unsigned long long) seqno, |
59348b19 | 150 | (unsigned long long) dp->dccps_swh, |
cbe1f5f8 GR |
151 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
152 | : "exists", | |
153 | (unsigned long long) lawl, (unsigned long long) ackno, | |
59348b19 | 154 | (unsigned long long) dp->dccps_awh); |
a94f0f97 GR |
155 | |
156 | dp->dccps_rate_last = now; | |
157 | ||
e155d769 GR |
158 | if (dh->dccph_type == DCCP_PKT_RESET) |
159 | seqno = dp->dccps_gsr; | |
cbe1f5f8 | 160 | dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
7c657876 ACM |
161 | return -1; |
162 | } | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
c25a18ba ACM |
167 | static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
168 | const struct dccp_hdr *dh, const unsigned len) | |
7c657876 ACM |
169 | { |
170 | struct dccp_sock *dp = dccp_sk(sk); | |
171 | ||
7c657876 ACM |
172 | switch (dccp_hdr(skb)->dccph_type) { |
173 | case DCCP_PKT_DATAACK: | |
174 | case DCCP_PKT_DATA: | |
175 | /* | |
7690af3f ACM |
176 | * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED |
177 | * option if it is. | |
7c657876 ACM |
178 | */ |
179 | __skb_pull(skb, dh->dccph_doff * 4); | |
180 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
181 | skb_set_owner_r(skb, sk); | |
182 | sk->sk_data_ready(sk, 0); | |
183 | return 0; | |
184 | case DCCP_PKT_ACK: | |
185 | goto discard; | |
186 | case DCCP_PKT_RESET: | |
187 | /* | |
188 | * Step 9: Process Reset | |
189 | * If P.type == Reset, | |
190 | * Tear down connection | |
191 | * S.state := TIMEWAIT | |
192 | * Set TIMEWAIT timer | |
193 | * Drop packet and return | |
194 | */ | |
195 | dccp_fin(sk, skb); | |
196 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
197 | return 0; | |
198 | case DCCP_PKT_CLOSEREQ: | |
199 | dccp_rcv_closereq(sk, skb); | |
200 | goto discard; | |
201 | case DCCP_PKT_CLOSE: | |
202 | dccp_rcv_close(sk, skb); | |
203 | return 0; | |
204 | case DCCP_PKT_REQUEST: | |
8109b02b ACM |
205 | /* Step 7 |
206 | * or (S.is_server and P.type == Response) | |
7c657876 ACM |
207 | * or (S.is_client and P.type == Request) |
208 | * or (S.state >= OPEN and P.type == Request | |
209 | * and P.seqno >= S.OSR) | |
210 | * or (S.state >= OPEN and P.type == Response | |
211 | * and P.seqno >= S.OSR) | |
212 | * or (S.state == RESPOND and P.type == Data), | |
213 | * Send Sync packet acknowledging P.seqno | |
214 | * Drop packet and return | |
215 | */ | |
216 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
217 | goto send_sync; | |
218 | goto check_seq; | |
219 | case DCCP_PKT_RESPONSE: | |
220 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
221 | goto send_sync; | |
222 | check_seq: | |
8d13bf9a GR |
223 | if (dccp_delta_seqno(dp->dccps_osr, |
224 | DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { | |
7c657876 | 225 | send_sync: |
e92ae93a ACM |
226 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
227 | DCCP_PKT_SYNC); | |
7c657876 ACM |
228 | } |
229 | break; | |
e92ae93a ACM |
230 | case DCCP_PKT_SYNC: |
231 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
232 | DCCP_PKT_SYNCACK); | |
233 | /* | |
0e64e94e | 234 | * From RFC 4340, sec. 5.7 |
e92ae93a ACM |
235 | * |
236 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
237 | * MAY have non-zero-length application data areas, whose | |
0e64e94e | 238 | * contents receivers MUST ignore. |
e92ae93a ACM |
239 | */ |
240 | goto discard; | |
7c657876 ACM |
241 | } |
242 | ||
243 | DCCP_INC_STATS_BH(DCCP_MIB_INERRS); | |
244 | discard: | |
245 | __kfree_skb(skb); | |
246 | return 0; | |
247 | } | |
248 | ||
709dd3aa AB |
249 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
250 | const struct dccp_hdr *dh, const unsigned len) | |
251 | { | |
252 | struct dccp_sock *dp = dccp_sk(sk); | |
253 | ||
254 | if (dccp_check_seqno(sk, skb)) | |
255 | goto discard; | |
256 | ||
257 | if (dccp_parse_options(sk, skb)) | |
258 | goto discard; | |
259 | ||
260 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
261 | dccp_event_ack_recv(sk, skb); | |
262 | ||
a4bf3902 | 263 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
709dd3aa AB |
264 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
265 | DCCP_SKB_CB(skb)->dccpd_seq, | |
266 | DCCP_ACKVEC_STATE_RECEIVED)) | |
267 | goto discard; | |
268 | ||
151a9931 GR |
269 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); |
270 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
709dd3aa AB |
271 | |
272 | return __dccp_rcv_established(sk, skb, dh, len); | |
273 | discard: | |
274 | __kfree_skb(skb); | |
275 | return 0; | |
276 | } | |
277 | ||
f21e68ca ACM |
278 | EXPORT_SYMBOL_GPL(dccp_rcv_established); |
279 | ||
7c657876 ACM |
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 | { | |
8109b02b | 285 | /* |
7c657876 ACM |
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); | |
3393da82 | 299 | long tstamp = dccp_timestamp(); |
7c657876 ACM |
300 | |
301 | /* Stop the REQUEST timer */ | |
302 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
303 | BUG_TRAP(sk->sk_send_head != NULL); | |
304 | __kfree_skb(sk->sk_send_head); | |
305 | sk->sk_send_head = NULL; | |
306 | ||
7690af3f ACM |
307 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
308 | dp->dccps_awl, dp->dccps_awh)) { | |
309 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
310 | "P.ackno=%llu, S.AWH=%llu \n", | |
311 | (unsigned long long)dp->dccps_awl, | |
312 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
313 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
314 | goto out_invalid_packet; |
315 | } | |
9e377202 | 316 | |
afe00251 AB |
317 | if (dccp_parse_options(sk, skb)) |
318 | goto out_invalid_packet; | |
319 | ||
3393da82 GR |
320 | /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ |
321 | if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) | |
322 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - | |
323 | dp->dccps_options_received.dccpor_timestamp_echo)); | |
89560b53 | 324 | |
c9eaf173 YH |
325 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
326 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, | |
327 | DCCP_SKB_CB(skb)->dccpd_seq, | |
328 | DCCP_ACKVEC_STATE_RECEIVED)) | |
329 | goto out_invalid_packet; /* FIXME: change error code */ | |
7c657876 ACM |
330 | |
331 | dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; | |
03ace394 ACM |
332 | dccp_update_gsr(sk, dp->dccps_isr); |
333 | /* | |
334 | * SWL and AWL are initially adjusted so that they are not less than | |
335 | * the initial Sequence Numbers received and sent, respectively: | |
336 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
337 | * AWL := max(GSS - W' + 1, ISS). | |
338 | * These adjustments MUST be applied only at the beginning of the | |
339 | * connection. | |
340 | * | |
341 | * AWL was adjusted in dccp_v4_connect -acme | |
342 | */ | |
343 | dccp_set_seqno(&dp->dccps_swl, | |
344 | max48(dp->dccps_swl, dp->dccps_isr)); | |
7c657876 | 345 | |
d83d8461 | 346 | dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
7c657876 ACM |
347 | |
348 | /* | |
349 | * Step 10: Process REQUEST state (second part) | |
350 | * If S.state == REQUEST, | |
7690af3f ACM |
351 | * / * If we get here, P is a valid Response from the |
352 | * server (see Step 4), and we should move to | |
353 | * PARTOPEN state. PARTOPEN means send an Ack, | |
354 | * don't send Data packets, retransmit Acks | |
355 | * periodically, and always include any Init Cookie | |
356 | * from the Response * / | |
7c657876 ACM |
357 | * S.state := PARTOPEN |
358 | * Set PARTOPEN timer | |
8109b02b | 359 | * Continue with S.state == PARTOPEN |
7690af3f ACM |
360 | * / * Step 12 will send the Ack completing the |
361 | * three-way handshake * / | |
7c657876 ACM |
362 | */ |
363 | dccp_set_state(sk, DCCP_PARTOPEN); | |
364 | ||
365 | /* Make sure socket is routed, for correct metrics. */ | |
57cca05a | 366 | icsk->icsk_af_ops->rebuild_header(sk); |
7c657876 ACM |
367 | |
368 | if (!sock_flag(sk, SOCK_DEAD)) { | |
369 | sk->sk_state_change(sk); | |
370 | sk_wake_async(sk, 0, POLL_OUT); | |
371 | } | |
372 | ||
373 | if (sk->sk_write_pending || icsk->icsk_ack.pingpong || | |
374 | icsk->icsk_accept_queue.rskq_defer_accept) { | |
375 | /* Save one ACK. Data will be ready after | |
376 | * several ticks, if write_pending is set. | |
377 | * | |
378 | * It may be deleted, but with this feature tcpdumps | |
379 | * look so _wonderfully_ clever, that I was not able | |
380 | * to stand against the temptation 8) --ANK | |
381 | */ | |
382 | /* | |
383 | * OK, in DCCP we can as well do a similar trick, its | |
384 | * even in the draft, but there is no need for us to | |
385 | * schedule an ack here, as dccp_sendmsg does this for | |
386 | * us, also stated in the draft. -acme | |
387 | */ | |
388 | __kfree_skb(skb); | |
389 | return 0; | |
8109b02b | 390 | } |
7c657876 ACM |
391 | dccp_send_ack(sk); |
392 | return -1; | |
393 | } | |
394 | ||
395 | out_invalid_packet: | |
0c10c5d9 ACM |
396 | /* dccp_v4_do_rcv will send a reset */ |
397 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
8109b02b | 398 | return 1; |
7c657876 ACM |
399 | } |
400 | ||
401 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
402 | struct sk_buff *skb, | |
403 | const struct dccp_hdr *dh, | |
404 | const unsigned len) | |
405 | { | |
406 | int queued = 0; | |
407 | ||
408 | switch (dh->dccph_type) { | |
409 | case DCCP_PKT_RESET: | |
410 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
411 | break; | |
2a9bc9bb ACM |
412 | case DCCP_PKT_DATA: |
413 | if (sk->sk_state == DCCP_RESPOND) | |
414 | break; | |
7c657876 ACM |
415 | case DCCP_PKT_DATAACK: |
416 | case DCCP_PKT_ACK: | |
417 | /* | |
7690af3f ACM |
418 | * FIXME: we should be reseting the PARTOPEN (DELACK) timer |
419 | * here but only if we haven't used the DELACK timer for | |
420 | * something else, like sending a delayed ack for a TIMESTAMP | |
421 | * echo, etc, for now were not clearing it, sending an extra | |
422 | * ACK when there is nothing else to do in DELACK is not a big | |
423 | * deal after all. | |
7c657876 ACM |
424 | */ |
425 | ||
426 | /* Stop the PARTOPEN timer */ | |
427 | if (sk->sk_state == DCCP_PARTOPEN) | |
428 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
429 | ||
430 | dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
431 | dccp_set_state(sk, DCCP_OPEN); | |
432 | ||
2a9bc9bb ACM |
433 | if (dh->dccph_type == DCCP_PKT_DATAACK || |
434 | dh->dccph_type == DCCP_PKT_DATA) { | |
709dd3aa | 435 | __dccp_rcv_established(sk, skb, dh, len); |
7690af3f | 436 | queued = 1; /* packet was queued |
709dd3aa | 437 | (by __dccp_rcv_established) */ |
7c657876 ACM |
438 | } |
439 | break; | |
440 | } | |
441 | ||
442 | return queued; | |
443 | } | |
444 | ||
445 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
446 | struct dccp_hdr *dh, unsigned len) | |
447 | { | |
448 | struct dccp_sock *dp = dccp_sk(sk); | |
0c10c5d9 | 449 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
7c657876 ACM |
450 | const int old_state = sk->sk_state; |
451 | int queued = 0; | |
452 | ||
8649b0d4 ACM |
453 | /* |
454 | * Step 3: Process LISTEN state | |
8649b0d4 ACM |
455 | * |
456 | * If S.state == LISTEN, | |
d83ca5ac GR |
457 | * If P.type == Request or P contains a valid Init Cookie option, |
458 | * (* Must scan the packet's options to check for Init | |
459 | * Cookies. Only Init Cookies are processed here, | |
460 | * however; other options are processed in Step 8. This | |
461 | * scan need only be performed if the endpoint uses Init | |
462 | * Cookies *) | |
463 | * (* Generate a new socket and switch to that socket *) | |
464 | * Set S := new socket for this port pair | |
465 | * S.state = RESPOND | |
466 | * Choose S.ISS (initial seqno) or set from Init Cookies | |
467 | * Initialize S.GAR := S.ISS | |
468 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init | |
469 | * Cookies Continue with S.state == RESPOND | |
470 | * (* A Response packet will be generated in Step 11 *) | |
471 | * Otherwise, | |
472 | * Generate Reset(No Connection) unless P.type == Reset | |
473 | * Drop packet and return | |
8649b0d4 ACM |
474 | */ |
475 | if (sk->sk_state == DCCP_LISTEN) { | |
476 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
57cca05a ACM |
477 | if (inet_csk(sk)->icsk_af_ops->conn_request(sk, |
478 | skb) < 0) | |
8649b0d4 ACM |
479 | return 1; |
480 | ||
481 | /* FIXME: do congestion control initialization */ | |
482 | goto discard; | |
483 | } | |
484 | if (dh->dccph_type == DCCP_PKT_RESET) | |
485 | goto discard; | |
486 | ||
0c10c5d9 ACM |
487 | /* Caller (dccp_v4_do_rcv) will send Reset */ |
488 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
8649b0d4 ACM |
489 | return 1; |
490 | } | |
491 | ||
492 | if (sk->sk_state != DCCP_REQUESTING) { | |
7c657876 ACM |
493 | if (dccp_check_seqno(sk, skb)) |
494 | goto discard; | |
495 | ||
496 | /* | |
497 | * Step 8: Process options and mark acknowledgeable | |
498 | */ | |
499 | if (dccp_parse_options(sk, skb)) | |
500 | goto discard; | |
501 | ||
0c10c5d9 | 502 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) |
7c657876 ACM |
503 | dccp_event_ack_recv(sk, skb); |
504 | ||
8109b02b | 505 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
ae31c339 | 506 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
8109b02b ACM |
507 | DCCP_SKB_CB(skb)->dccpd_seq, |
508 | DCCP_ACKVEC_STATE_RECEIVED)) | |
509 | goto discard; | |
e84a9f5e | 510 | |
151a9931 GR |
511 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); |
512 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
7c657876 ACM |
513 | } |
514 | ||
515 | /* | |
516 | * Step 9: Process Reset | |
517 | * If P.type == Reset, | |
518 | * Tear down connection | |
519 | * S.state := TIMEWAIT | |
520 | * Set TIMEWAIT timer | |
521 | * Drop packet and return | |
522 | */ | |
523 | if (dh->dccph_type == DCCP_PKT_RESET) { | |
7690af3f ACM |
524 | /* |
525 | * Queue the equivalent of TCP fin so that dccp_recvmsg | |
526 | * exits the loop | |
527 | */ | |
7c657876 ACM |
528 | dccp_fin(sk, skb); |
529 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
530 | return 0; | |
531 | /* | |
532 | * Step 7: Check for unexpected packet types | |
533 | * If (S.is_server and P.type == CloseReq) | |
534 | * or (S.is_server and P.type == Response) | |
535 | * or (S.is_client and P.type == Request) | |
536 | * or (S.state == RESPOND and P.type == Data), | |
537 | * Send Sync packet acknowledging P.seqno | |
538 | * Drop packet and return | |
539 | */ | |
540 | } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
7690af3f ACM |
541 | (dh->dccph_type == DCCP_PKT_RESPONSE || |
542 | dh->dccph_type == DCCP_PKT_CLOSEREQ)) || | |
7c657876 ACM |
543 | (dp->dccps_role == DCCP_ROLE_CLIENT && |
544 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
7690af3f ACM |
545 | (sk->sk_state == DCCP_RESPOND && |
546 | dh->dccph_type == DCCP_PKT_DATA)) { | |
0c10c5d9 | 547 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 | 548 | goto discard; |
7ad07e7c ACM |
549 | } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { |
550 | dccp_rcv_closereq(sk, skb); | |
551 | goto discard; | |
552 | } else if (dh->dccph_type == DCCP_PKT_CLOSE) { | |
553 | dccp_rcv_close(sk, skb); | |
554 | return 0; | |
7c657876 ACM |
555 | } |
556 | ||
557 | switch (sk->sk_state) { | |
558 | case DCCP_CLOSED: | |
0c10c5d9 | 559 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; |
7c657876 ACM |
560 | return 1; |
561 | ||
7c657876 ACM |
562 | case DCCP_REQUESTING: |
563 | /* FIXME: do congestion control initialization */ | |
564 | ||
565 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); | |
566 | if (queued >= 0) | |
567 | return queued; | |
568 | ||
569 | __kfree_skb(skb); | |
570 | return 0; | |
571 | ||
572 | case DCCP_RESPOND: | |
573 | case DCCP_PARTOPEN: | |
7690af3f ACM |
574 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
575 | dh, len); | |
7c657876 ACM |
576 | break; |
577 | } | |
578 | ||
7690af3f ACM |
579 | if (dh->dccph_type == DCCP_PKT_ACK || |
580 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
581 | switch (old_state) { |
582 | case DCCP_PARTOPEN: | |
583 | sk->sk_state_change(sk); | |
584 | sk_wake_async(sk, 0, POLL_OUT); | |
585 | break; | |
586 | } | |
08831700 GR |
587 | } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
588 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); | |
589 | goto discard; | |
7c657876 ACM |
590 | } |
591 | ||
8109b02b | 592 | if (!queued) { |
7c657876 ACM |
593 | discard: |
594 | __kfree_skb(skb); | |
595 | } | |
596 | return 0; | |
597 | } | |
f21e68ca ACM |
598 | |
599 | EXPORT_SYMBOL_GPL(dccp_rcv_state_process); | |
4712a792 GR |
600 | |
601 | /** | |
3393da82 GR |
602 | * dccp_sample_rtt - Validate and finalise computation of RTT sample |
603 | * @delta: number of microseconds between packet and acknowledgment | |
604 | * The routine is kept generic to work in different contexts. It should be | |
605 | * called immediately when the ACK used for the RTT sample arrives. | |
4712a792 | 606 | */ |
3393da82 | 607 | u32 dccp_sample_rtt(struct sock *sk, long delta) |
4712a792 | 608 | { |
3393da82 GR |
609 | /* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
610 | delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; | |
4712a792 GR |
611 | |
612 | if (unlikely(delta <= 0)) { | |
3393da82 | 613 | DCCP_WARN("unusable RTT sample %ld, using min\n", delta); |
4712a792 GR |
614 | return DCCP_SANE_RTT_MIN; |
615 | } | |
3393da82 GR |
616 | if (unlikely(delta > DCCP_SANE_RTT_MAX)) { |
617 | DCCP_WARN("RTT sample %ld too large, using max\n", delta); | |
4712a792 GR |
618 | return DCCP_SANE_RTT_MAX; |
619 | } | |
620 | ||
621 | return delta; | |
622 | } | |
623 | ||
624 | EXPORT_SYMBOL_GPL(dccp_sample_rtt); |