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 | ||
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 | { | |
017487d7 | 34 | dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED); |
7ad07e7c ACM |
35 | dccp_fin(sk, skb); |
36 | dccp_set_state(sk, DCCP_CLOSED); | |
331968bd | 37 | sk_wake_async(sk, 1, POLL_HUP); |
7c657876 ACM |
38 | } |
39 | ||
40 | static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) | |
41 | { | |
42 | /* | |
43 | * Step 7: Check for unexpected packet types | |
44 | * If (S.is_server and P.type == CloseReq) | |
45 | * Send Sync packet acknowledging P.seqno | |
46 | * Drop packet and return | |
47 | */ | |
48 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { | |
e92ae93a | 49 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 ACM |
50 | return; |
51 | } | |
52 | ||
811265b8 ACM |
53 | if (sk->sk_state != DCCP_CLOSING) |
54 | dccp_set_state(sk, DCCP_CLOSING); | |
7ad07e7c | 55 | dccp_send_close(sk, 0); |
7c657876 ACM |
56 | } |
57 | ||
c25a18ba | 58 | static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
59 | { |
60 | struct dccp_sock *dp = dccp_sk(sk); | |
61 | ||
a4bf3902 | 62 | if (dccp_msk(sk)->dccpms_send_ack_vector) |
ae31c339 ACM |
63 | dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk, |
64 | DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
7c657876 ACM |
65 | } |
66 | ||
67 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) | |
68 | { | |
69 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
70 | struct dccp_sock *dp = dccp_sk(sk); | |
cbe1f5f8 GR |
71 | u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
72 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
7c657876 ACM |
73 | |
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 | */ | |
8109b02b | 86 | if (dh->dccph_type == DCCP_PKT_SYNC || |
7c657876 | 87 | dh->dccph_type == DCCP_PKT_SYNCACK) { |
cbe1f5f8 GR |
88 | if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && |
89 | dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) | |
90 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
91 | else |
92 | return -1; | |
e92ae93a | 93 | } |
c9eaf173 | 94 | |
7c657876 ACM |
95 | /* |
96 | * Step 6: Check sequence numbers | |
97 | * Let LSWL = S.SWL and LAWL = S.AWL | |
98 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
99 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
100 | * If LSWL <= P.seqno <= S.SWH | |
101 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
102 | * Update S.GSR, S.SWL, S.SWH | |
103 | * If P.type != Sync, | |
104 | * Update S.GAR | |
7c657876 | 105 | */ |
e92ae93a ACM |
106 | lswl = dp->dccps_swl; |
107 | lawl = dp->dccps_awl; | |
108 | ||
109 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
110 | dh->dccph_type == DCCP_PKT_CLOSE || |
111 | dh->dccph_type == DCCP_PKT_RESET) { | |
cbe1f5f8 | 112 | lswl = ADD48(dp->dccps_gsr, 1); |
7c657876 ACM |
113 | lawl = dp->dccps_gar; |
114 | } | |
115 | ||
cbe1f5f8 GR |
116 | if (between48(seqno, lswl, dp->dccps_swh) && |
117 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || | |
118 | between48(ackno, lawl, dp->dccps_awh))) { | |
119 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
120 | |
121 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
cbe1f5f8 GR |
122 | (ackno != DCCP_PKT_WITHOUT_ACK_SEQ)) |
123 | dp->dccps_gar = ackno; | |
7c657876 | 124 | } else { |
a94f0f97 GR |
125 | unsigned long now = jiffies; |
126 | /* | |
127 | * Step 6: Check sequence numbers | |
128 | * Otherwise, | |
129 | * If P.type == Reset, | |
130 | * Send Sync packet acknowledging S.GSR | |
131 | * Otherwise, | |
132 | * Send Sync packet acknowledging P.seqno | |
133 | * Drop packet and return | |
134 | * | |
135 | * These Syncs are rate-limited as per RFC 4340, 7.5.4: | |
136 | * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. | |
137 | */ | |
138 | if (time_before(now, (dp->dccps_rate_last + | |
139 | sysctl_dccp_sync_ratelimit))) | |
140 | return 0; | |
141 | ||
59348b19 GR |
142 | DCCP_WARN("DCCP: Step 6 failed for %s packet, " |
143 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " | |
144 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
145 | "sending SYNC...\n", dccp_packet_name(dh->dccph_type), | |
cbe1f5f8 | 146 | (unsigned long long) lswl, (unsigned long long) seqno, |
59348b19 | 147 | (unsigned long long) dp->dccps_swh, |
cbe1f5f8 GR |
148 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
149 | : "exists", | |
150 | (unsigned long long) lawl, (unsigned long long) ackno, | |
59348b19 | 151 | (unsigned long long) dp->dccps_awh); |
a94f0f97 GR |
152 | |
153 | dp->dccps_rate_last = now; | |
154 | ||
e155d769 GR |
155 | if (dh->dccph_type == DCCP_PKT_RESET) |
156 | seqno = dp->dccps_gsr; | |
cbe1f5f8 | 157 | dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
7c657876 ACM |
158 | return -1; |
159 | } | |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
c25a18ba ACM |
164 | static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
165 | const struct dccp_hdr *dh, const unsigned len) | |
7c657876 ACM |
166 | { |
167 | struct dccp_sock *dp = dccp_sk(sk); | |
168 | ||
7c657876 ACM |
169 | switch (dccp_hdr(skb)->dccph_type) { |
170 | case DCCP_PKT_DATAACK: | |
171 | case DCCP_PKT_DATA: | |
172 | /* | |
7690af3f ACM |
173 | * FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED |
174 | * option if it is. | |
7c657876 ACM |
175 | */ |
176 | __skb_pull(skb, dh->dccph_doff * 4); | |
177 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
178 | skb_set_owner_r(skb, sk); | |
179 | sk->sk_data_ready(sk, 0); | |
180 | return 0; | |
181 | case DCCP_PKT_ACK: | |
182 | goto discard; | |
183 | case DCCP_PKT_RESET: | |
184 | /* | |
185 | * Step 9: Process Reset | |
186 | * If P.type == Reset, | |
187 | * Tear down connection | |
188 | * S.state := TIMEWAIT | |
189 | * Set TIMEWAIT timer | |
190 | * Drop packet and return | |
191 | */ | |
192 | dccp_fin(sk, skb); | |
193 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
194 | return 0; | |
195 | case DCCP_PKT_CLOSEREQ: | |
196 | dccp_rcv_closereq(sk, skb); | |
197 | goto discard; | |
198 | case DCCP_PKT_CLOSE: | |
199 | dccp_rcv_close(sk, skb); | |
200 | return 0; | |
201 | case DCCP_PKT_REQUEST: | |
8109b02b ACM |
202 | /* Step 7 |
203 | * or (S.is_server and P.type == Response) | |
7c657876 ACM |
204 | * or (S.is_client and P.type == Request) |
205 | * or (S.state >= OPEN and P.type == Request | |
206 | * and P.seqno >= S.OSR) | |
207 | * or (S.state >= OPEN and P.type == Response | |
208 | * and P.seqno >= S.OSR) | |
209 | * or (S.state == RESPOND and P.type == Data), | |
210 | * Send Sync packet acknowledging P.seqno | |
211 | * Drop packet and return | |
212 | */ | |
213 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
214 | goto send_sync; | |
215 | goto check_seq; | |
216 | case DCCP_PKT_RESPONSE: | |
217 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
218 | goto send_sync; | |
219 | check_seq: | |
8d13bf9a GR |
220 | if (dccp_delta_seqno(dp->dccps_osr, |
221 | DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { | |
7c657876 | 222 | send_sync: |
e92ae93a ACM |
223 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
224 | DCCP_PKT_SYNC); | |
7c657876 ACM |
225 | } |
226 | break; | |
e92ae93a ACM |
227 | case DCCP_PKT_SYNC: |
228 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
229 | DCCP_PKT_SYNCACK); | |
230 | /* | |
0e64e94e | 231 | * From RFC 4340, sec. 5.7 |
e92ae93a ACM |
232 | * |
233 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
234 | * MAY have non-zero-length application data areas, whose | |
0e64e94e | 235 | * contents receivers MUST ignore. |
e92ae93a ACM |
236 | */ |
237 | goto discard; | |
7c657876 ACM |
238 | } |
239 | ||
240 | DCCP_INC_STATS_BH(DCCP_MIB_INERRS); | |
241 | discard: | |
242 | __kfree_skb(skb); | |
243 | return 0; | |
244 | } | |
245 | ||
709dd3aa AB |
246 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
247 | const struct dccp_hdr *dh, const unsigned len) | |
248 | { | |
249 | struct dccp_sock *dp = dccp_sk(sk); | |
250 | ||
251 | if (dccp_check_seqno(sk, skb)) | |
252 | goto discard; | |
253 | ||
254 | if (dccp_parse_options(sk, skb)) | |
255 | goto discard; | |
256 | ||
257 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
258 | dccp_event_ack_recv(sk, skb); | |
259 | ||
a4bf3902 | 260 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
709dd3aa AB |
261 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
262 | DCCP_SKB_CB(skb)->dccpd_seq, | |
263 | DCCP_ACKVEC_STATE_RECEIVED)) | |
264 | goto discard; | |
265 | ||
151a9931 GR |
266 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); |
267 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
709dd3aa AB |
268 | |
269 | return __dccp_rcv_established(sk, skb, dh, len); | |
270 | discard: | |
271 | __kfree_skb(skb); | |
272 | return 0; | |
273 | } | |
274 | ||
f21e68ca ACM |
275 | EXPORT_SYMBOL_GPL(dccp_rcv_established); |
276 | ||
7c657876 ACM |
277 | static int dccp_rcv_request_sent_state_process(struct sock *sk, |
278 | struct sk_buff *skb, | |
279 | const struct dccp_hdr *dh, | |
280 | const unsigned len) | |
281 | { | |
8109b02b | 282 | /* |
7c657876 ACM |
283 | * Step 4: Prepare sequence numbers in REQUEST |
284 | * If S.state == REQUEST, | |
285 | * If (P.type == Response or P.type == Reset) | |
286 | * and S.AWL <= P.ackno <= S.AWH, | |
287 | * / * Set sequence number variables corresponding to the | |
288 | * other endpoint, so P will pass the tests in Step 6 * / | |
289 | * Set S.GSR, S.ISR, S.SWL, S.SWH | |
290 | * / * Response processing continues in Step 10; Reset | |
291 | * processing continues in Step 9 * / | |
292 | */ | |
293 | if (dh->dccph_type == DCCP_PKT_RESPONSE) { | |
294 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
295 | struct dccp_sock *dp = dccp_sk(sk); | |
3393da82 | 296 | long tstamp = dccp_timestamp(); |
7c657876 ACM |
297 | |
298 | /* Stop the REQUEST timer */ | |
299 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
300 | BUG_TRAP(sk->sk_send_head != NULL); | |
301 | __kfree_skb(sk->sk_send_head); | |
302 | sk->sk_send_head = NULL; | |
303 | ||
7690af3f ACM |
304 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
305 | dp->dccps_awl, dp->dccps_awh)) { | |
306 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
307 | "P.ackno=%llu, S.AWH=%llu \n", | |
308 | (unsigned long long)dp->dccps_awl, | |
309 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
310 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
311 | goto out_invalid_packet; |
312 | } | |
9e377202 | 313 | |
afe00251 AB |
314 | if (dccp_parse_options(sk, skb)) |
315 | goto out_invalid_packet; | |
316 | ||
3393da82 GR |
317 | /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ |
318 | if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) | |
319 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - | |
320 | dp->dccps_options_received.dccpor_timestamp_echo)); | |
89560b53 | 321 | |
c9eaf173 YH |
322 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
323 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, | |
324 | DCCP_SKB_CB(skb)->dccpd_seq, | |
325 | DCCP_ACKVEC_STATE_RECEIVED)) | |
326 | goto out_invalid_packet; /* FIXME: change error code */ | |
7c657876 ACM |
327 | |
328 | dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; | |
03ace394 ACM |
329 | dccp_update_gsr(sk, dp->dccps_isr); |
330 | /* | |
331 | * SWL and AWL are initially adjusted so that they are not less than | |
332 | * the initial Sequence Numbers received and sent, respectively: | |
333 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
334 | * AWL := max(GSS - W' + 1, ISS). | |
335 | * These adjustments MUST be applied only at the beginning of the | |
336 | * connection. | |
337 | * | |
338 | * AWL was adjusted in dccp_v4_connect -acme | |
339 | */ | |
340 | dccp_set_seqno(&dp->dccps_swl, | |
341 | max48(dp->dccps_swl, dp->dccps_isr)); | |
7c657876 | 342 | |
d83d8461 | 343 | dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
7c657876 ACM |
344 | |
345 | /* | |
346 | * Step 10: Process REQUEST state (second part) | |
347 | * If S.state == REQUEST, | |
7690af3f ACM |
348 | * / * If we get here, P is a valid Response from the |
349 | * server (see Step 4), and we should move to | |
350 | * PARTOPEN state. PARTOPEN means send an Ack, | |
351 | * don't send Data packets, retransmit Acks | |
352 | * periodically, and always include any Init Cookie | |
353 | * from the Response * / | |
7c657876 ACM |
354 | * S.state := PARTOPEN |
355 | * Set PARTOPEN timer | |
8109b02b | 356 | * Continue with S.state == PARTOPEN |
7690af3f ACM |
357 | * / * Step 12 will send the Ack completing the |
358 | * three-way handshake * / | |
7c657876 ACM |
359 | */ |
360 | dccp_set_state(sk, DCCP_PARTOPEN); | |
361 | ||
362 | /* Make sure socket is routed, for correct metrics. */ | |
57cca05a | 363 | icsk->icsk_af_ops->rebuild_header(sk); |
7c657876 ACM |
364 | |
365 | if (!sock_flag(sk, SOCK_DEAD)) { | |
366 | sk->sk_state_change(sk); | |
367 | sk_wake_async(sk, 0, POLL_OUT); | |
368 | } | |
369 | ||
370 | if (sk->sk_write_pending || icsk->icsk_ack.pingpong || | |
371 | icsk->icsk_accept_queue.rskq_defer_accept) { | |
372 | /* Save one ACK. Data will be ready after | |
373 | * several ticks, if write_pending is set. | |
374 | * | |
375 | * It may be deleted, but with this feature tcpdumps | |
376 | * look so _wonderfully_ clever, that I was not able | |
377 | * to stand against the temptation 8) --ANK | |
378 | */ | |
379 | /* | |
380 | * OK, in DCCP we can as well do a similar trick, its | |
381 | * even in the draft, but there is no need for us to | |
382 | * schedule an ack here, as dccp_sendmsg does this for | |
383 | * us, also stated in the draft. -acme | |
384 | */ | |
385 | __kfree_skb(skb); | |
386 | return 0; | |
8109b02b | 387 | } |
7c657876 ACM |
388 | dccp_send_ack(sk); |
389 | return -1; | |
390 | } | |
391 | ||
392 | out_invalid_packet: | |
0c10c5d9 ACM |
393 | /* dccp_v4_do_rcv will send a reset */ |
394 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
8109b02b | 395 | return 1; |
7c657876 ACM |
396 | } |
397 | ||
398 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
399 | struct sk_buff *skb, | |
400 | const struct dccp_hdr *dh, | |
401 | const unsigned len) | |
402 | { | |
403 | int queued = 0; | |
404 | ||
405 | switch (dh->dccph_type) { | |
406 | case DCCP_PKT_RESET: | |
407 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
408 | break; | |
2a9bc9bb ACM |
409 | case DCCP_PKT_DATA: |
410 | if (sk->sk_state == DCCP_RESPOND) | |
411 | break; | |
7c657876 ACM |
412 | case DCCP_PKT_DATAACK: |
413 | case DCCP_PKT_ACK: | |
414 | /* | |
7690af3f ACM |
415 | * FIXME: we should be reseting the PARTOPEN (DELACK) timer |
416 | * here but only if we haven't used the DELACK timer for | |
417 | * something else, like sending a delayed ack for a TIMESTAMP | |
418 | * echo, etc, for now were not clearing it, sending an extra | |
419 | * ACK when there is nothing else to do in DELACK is not a big | |
420 | * deal after all. | |
7c657876 ACM |
421 | */ |
422 | ||
423 | /* Stop the PARTOPEN timer */ | |
424 | if (sk->sk_state == DCCP_PARTOPEN) | |
425 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
426 | ||
427 | dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
428 | dccp_set_state(sk, DCCP_OPEN); | |
429 | ||
2a9bc9bb ACM |
430 | if (dh->dccph_type == DCCP_PKT_DATAACK || |
431 | dh->dccph_type == DCCP_PKT_DATA) { | |
709dd3aa | 432 | __dccp_rcv_established(sk, skb, dh, len); |
7690af3f | 433 | queued = 1; /* packet was queued |
709dd3aa | 434 | (by __dccp_rcv_established) */ |
7c657876 ACM |
435 | } |
436 | break; | |
437 | } | |
438 | ||
439 | return queued; | |
440 | } | |
441 | ||
442 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
443 | struct dccp_hdr *dh, unsigned len) | |
444 | { | |
445 | struct dccp_sock *dp = dccp_sk(sk); | |
0c10c5d9 | 446 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
7c657876 ACM |
447 | const int old_state = sk->sk_state; |
448 | int queued = 0; | |
449 | ||
8649b0d4 ACM |
450 | /* |
451 | * Step 3: Process LISTEN state | |
8649b0d4 ACM |
452 | * |
453 | * If S.state == LISTEN, | |
d83ca5ac GR |
454 | * If P.type == Request or P contains a valid Init Cookie option, |
455 | * (* Must scan the packet's options to check for Init | |
456 | * Cookies. Only Init Cookies are processed here, | |
457 | * however; other options are processed in Step 8. This | |
458 | * scan need only be performed if the endpoint uses Init | |
459 | * Cookies *) | |
460 | * (* Generate a new socket and switch to that socket *) | |
461 | * Set S := new socket for this port pair | |
462 | * S.state = RESPOND | |
463 | * Choose S.ISS (initial seqno) or set from Init Cookies | |
464 | * Initialize S.GAR := S.ISS | |
465 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init | |
466 | * Cookies Continue with S.state == RESPOND | |
467 | * (* A Response packet will be generated in Step 11 *) | |
468 | * Otherwise, | |
469 | * Generate Reset(No Connection) unless P.type == Reset | |
470 | * Drop packet and return | |
8649b0d4 ACM |
471 | */ |
472 | if (sk->sk_state == DCCP_LISTEN) { | |
473 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
57cca05a ACM |
474 | if (inet_csk(sk)->icsk_af_ops->conn_request(sk, |
475 | skb) < 0) | |
8649b0d4 ACM |
476 | return 1; |
477 | ||
478 | /* FIXME: do congestion control initialization */ | |
479 | goto discard; | |
480 | } | |
481 | if (dh->dccph_type == DCCP_PKT_RESET) | |
482 | goto discard; | |
483 | ||
0c10c5d9 ACM |
484 | /* Caller (dccp_v4_do_rcv) will send Reset */ |
485 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
8649b0d4 ACM |
486 | return 1; |
487 | } | |
488 | ||
489 | if (sk->sk_state != DCCP_REQUESTING) { | |
7c657876 ACM |
490 | if (dccp_check_seqno(sk, skb)) |
491 | goto discard; | |
492 | ||
493 | /* | |
494 | * Step 8: Process options and mark acknowledgeable | |
495 | */ | |
496 | if (dccp_parse_options(sk, skb)) | |
497 | goto discard; | |
498 | ||
0c10c5d9 | 499 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) |
7c657876 ACM |
500 | dccp_event_ack_recv(sk, skb); |
501 | ||
8109b02b | 502 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
ae31c339 | 503 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
8109b02b ACM |
504 | DCCP_SKB_CB(skb)->dccpd_seq, |
505 | DCCP_ACKVEC_STATE_RECEIVED)) | |
506 | goto discard; | |
e84a9f5e | 507 | |
151a9931 GR |
508 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); |
509 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
7c657876 ACM |
510 | } |
511 | ||
512 | /* | |
513 | * Step 9: Process Reset | |
514 | * If P.type == Reset, | |
515 | * Tear down connection | |
516 | * S.state := TIMEWAIT | |
517 | * Set TIMEWAIT timer | |
518 | * Drop packet and return | |
519 | */ | |
520 | if (dh->dccph_type == DCCP_PKT_RESET) { | |
7690af3f ACM |
521 | /* |
522 | * Queue the equivalent of TCP fin so that dccp_recvmsg | |
523 | * exits the loop | |
524 | */ | |
7c657876 ACM |
525 | dccp_fin(sk, skb); |
526 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
527 | return 0; | |
528 | /* | |
529 | * Step 7: Check for unexpected packet types | |
530 | * If (S.is_server and P.type == CloseReq) | |
531 | * or (S.is_server and P.type == Response) | |
532 | * or (S.is_client and P.type == Request) | |
533 | * or (S.state == RESPOND and P.type == Data), | |
534 | * Send Sync packet acknowledging P.seqno | |
535 | * Drop packet and return | |
536 | */ | |
537 | } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
7690af3f ACM |
538 | (dh->dccph_type == DCCP_PKT_RESPONSE || |
539 | dh->dccph_type == DCCP_PKT_CLOSEREQ)) || | |
7c657876 ACM |
540 | (dp->dccps_role == DCCP_ROLE_CLIENT && |
541 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
7690af3f ACM |
542 | (sk->sk_state == DCCP_RESPOND && |
543 | dh->dccph_type == DCCP_PKT_DATA)) { | |
0c10c5d9 | 544 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 | 545 | goto discard; |
7ad07e7c ACM |
546 | } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { |
547 | dccp_rcv_closereq(sk, skb); | |
548 | goto discard; | |
549 | } else if (dh->dccph_type == DCCP_PKT_CLOSE) { | |
550 | dccp_rcv_close(sk, skb); | |
551 | return 0; | |
7c657876 ACM |
552 | } |
553 | ||
554 | switch (sk->sk_state) { | |
555 | case DCCP_CLOSED: | |
0c10c5d9 | 556 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; |
7c657876 ACM |
557 | return 1; |
558 | ||
7c657876 ACM |
559 | case DCCP_REQUESTING: |
560 | /* FIXME: do congestion control initialization */ | |
561 | ||
562 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); | |
563 | if (queued >= 0) | |
564 | return queued; | |
565 | ||
566 | __kfree_skb(skb); | |
567 | return 0; | |
568 | ||
569 | case DCCP_RESPOND: | |
570 | case DCCP_PARTOPEN: | |
7690af3f ACM |
571 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
572 | dh, len); | |
7c657876 ACM |
573 | break; |
574 | } | |
575 | ||
7690af3f ACM |
576 | if (dh->dccph_type == DCCP_PKT_ACK || |
577 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
578 | switch (old_state) { |
579 | case DCCP_PARTOPEN: | |
580 | sk->sk_state_change(sk); | |
581 | sk_wake_async(sk, 0, POLL_OUT); | |
582 | break; | |
583 | } | |
08831700 GR |
584 | } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
585 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); | |
586 | goto discard; | |
7c657876 ACM |
587 | } |
588 | ||
8109b02b | 589 | if (!queued) { |
7c657876 ACM |
590 | discard: |
591 | __kfree_skb(skb); | |
592 | } | |
593 | return 0; | |
594 | } | |
f21e68ca ACM |
595 | |
596 | EXPORT_SYMBOL_GPL(dccp_rcv_state_process); | |
4712a792 GR |
597 | |
598 | /** | |
3393da82 GR |
599 | * dccp_sample_rtt - Validate and finalise computation of RTT sample |
600 | * @delta: number of microseconds between packet and acknowledgment | |
601 | * The routine is kept generic to work in different contexts. It should be | |
602 | * called immediately when the ACK used for the RTT sample arrives. | |
4712a792 | 603 | */ |
3393da82 | 604 | u32 dccp_sample_rtt(struct sock *sk, long delta) |
4712a792 | 605 | { |
3393da82 GR |
606 | /* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
607 | delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; | |
4712a792 GR |
608 | |
609 | if (unlikely(delta <= 0)) { | |
3393da82 | 610 | DCCP_WARN("unusable RTT sample %ld, using min\n", delta); |
4712a792 GR |
611 | return DCCP_SANE_RTT_MIN; |
612 | } | |
3393da82 GR |
613 | if (unlikely(delta > DCCP_SANE_RTT_MAX)) { |
614 | DCCP_WARN("RTT sample %ld too large, using max\n", delta); | |
4712a792 GR |
615 | return DCCP_SANE_RTT_MAX; |
616 | } | |
617 | ||
618 | return delta; | |
619 | } | |
620 | ||
621 | EXPORT_SYMBOL_GPL(dccp_sample_rtt); |