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 | ||
69567d0b | 25 | static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb) |
7c657876 | 26 | { |
7c657876 ACM |
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 | ||
69567d0b GR |
33 | static void dccp_fin(struct sock *sk, struct sk_buff *skb) |
34 | { | |
35 | /* | |
36 | * On receiving Close/CloseReq, both RD/WR shutdown are performed. | |
37 | * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after | |
38 | * receiving the closing segment, but there is no guarantee that such | |
39 | * data will be processed at all. | |
40 | */ | |
41 | sk->sk_shutdown = SHUTDOWN_MASK; | |
42 | sock_set_flag(sk, SOCK_DONE); | |
43 | dccp_enqueue_skb(sk, skb); | |
44 | } | |
45 | ||
0c869620 | 46 | static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb) |
7c657876 | 47 | { |
0c869620 GR |
48 | int queued = 0; |
49 | ||
50 | switch (sk->sk_state) { | |
51 | /* | |
52 | * We ignore Close when received in one of the following states: | |
53 | * - CLOSED (may be a late or duplicate packet) | |
54 | * - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier) | |
55 | * - RESPOND (already handled by dccp_check_req) | |
56 | */ | |
57 | case DCCP_CLOSING: | |
58 | /* | |
59 | * Simultaneous-close: receiving a Close after sending one. This | |
60 | * can happen if both client and server perform active-close and | |
61 | * will result in an endless ping-pong of crossing and retrans- | |
62 | * mitted Close packets, which only terminates when one of the | |
63 | * nodes times out (min. 64 seconds). Quicker convergence can be | |
64 | * achieved when one of the nodes acts as tie-breaker. | |
65 | * This is ok as both ends are done with data transfer and each | |
66 | * end is just waiting for the other to acknowledge termination. | |
67 | */ | |
68 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) | |
69 | break; | |
70 | /* fall through */ | |
71 | case DCCP_REQUESTING: | |
72 | case DCCP_ACTIVE_CLOSEREQ: | |
73 | dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED); | |
74 | dccp_done(sk); | |
75 | break; | |
76 | case DCCP_OPEN: | |
77 | case DCCP_PARTOPEN: | |
78 | /* Give waiting application a chance to read pending data */ | |
79 | queued = 1; | |
80 | dccp_fin(sk, skb); | |
81 | dccp_set_state(sk, DCCP_PASSIVE_CLOSE); | |
82 | /* fall through */ | |
83 | case DCCP_PASSIVE_CLOSE: | |
84 | /* | |
85 | * Retransmitted Close: we have already enqueued the first one. | |
86 | */ | |
87 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); | |
88 | } | |
89 | return queued; | |
7c657876 ACM |
90 | } |
91 | ||
0c869620 | 92 | static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) |
7c657876 | 93 | { |
0c869620 GR |
94 | int queued = 0; |
95 | ||
7c657876 ACM |
96 | /* |
97 | * Step 7: Check for unexpected packet types | |
98 | * If (S.is_server and P.type == CloseReq) | |
99 | * Send Sync packet acknowledging P.seqno | |
100 | * Drop packet and return | |
101 | */ | |
102 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { | |
e92ae93a | 103 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
0c869620 | 104 | return queued; |
7c657876 ACM |
105 | } |
106 | ||
0c869620 GR |
107 | /* Step 13: process relevant Client states < CLOSEREQ */ |
108 | switch (sk->sk_state) { | |
109 | case DCCP_REQUESTING: | |
110 | dccp_send_close(sk, 0); | |
811265b8 | 111 | dccp_set_state(sk, DCCP_CLOSING); |
0c869620 GR |
112 | break; |
113 | case DCCP_OPEN: | |
114 | case DCCP_PARTOPEN: | |
115 | /* Give waiting application a chance to read pending data */ | |
116 | queued = 1; | |
117 | dccp_fin(sk, skb); | |
118 | dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ); | |
119 | /* fall through */ | |
120 | case DCCP_PASSIVE_CLOSEREQ: | |
121 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); | |
122 | } | |
123 | return queued; | |
7c657876 ACM |
124 | } |
125 | ||
d8ef2c29 GR |
126 | static u8 dccp_reset_code_convert(const u8 code) |
127 | { | |
128 | const u8 error_code[] = { | |
129 | [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */ | |
130 | [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */ | |
131 | [DCCP_RESET_CODE_ABORTED] = ECONNRESET, | |
132 | ||
133 | [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED, | |
134 | [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED, | |
135 | [DCCP_RESET_CODE_TOO_BUSY] = EUSERS, | |
136 | [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT, | |
137 | ||
138 | [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG, | |
139 | [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR, | |
140 | [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC, | |
141 | [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ, | |
142 | [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP, | |
143 | }; | |
144 | ||
145 | return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code]; | |
146 | } | |
147 | ||
148 | static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb) | |
149 | { | |
150 | u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code); | |
151 | ||
152 | sk->sk_err = err; | |
153 | ||
154 | /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */ | |
155 | dccp_fin(sk, skb); | |
156 | ||
157 | if (err && !sock_flag(sk, SOCK_DEAD)) | |
8d8ad9d7 | 158 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR); |
d8ef2c29 GR |
159 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); |
160 | } | |
161 | ||
283fb4a5 | 162 | static void dccp_handle_ackvec_processing(struct sock *sk, struct sk_buff *skb) |
7c657876 | 163 | { |
283fb4a5 | 164 | struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec; |
7c657876 | 165 | |
283fb4a5 GR |
166 | if (av == NULL) |
167 | return; | |
168 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
169 | dccp_ackvec_clear_state(av, DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
170 | dccp_ackvec_input(av, skb); | |
7c657876 ACM |
171 | } |
172 | ||
8e8c71f1 GR |
173 | static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb) |
174 | { | |
175 | const struct dccp_sock *dp = dccp_sk(sk); | |
176 | ||
177 | /* Don't deliver to RX CCID when node has shut down read end. */ | |
178 | if (!(sk->sk_shutdown & RCV_SHUTDOWN)) | |
179 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); | |
180 | /* | |
181 | * Until the TX queue has been drained, we can not honour SHUT_WR, since | |
182 | * we need received feedback as input to adjust congestion control. | |
183 | */ | |
184 | if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN)) | |
185 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
186 | } | |
187 | ||
7c657876 ACM |
188 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) |
189 | { | |
190 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
191 | struct dccp_sock *dp = dccp_sk(sk); | |
cbe1f5f8 GR |
192 | u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
193 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
7c657876 ACM |
194 | |
195 | /* | |
196 | * Step 5: Prepare sequence numbers for Sync | |
197 | * If P.type == Sync or P.type == SyncAck, | |
198 | * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, | |
199 | * / * P is valid, so update sequence number variables | |
200 | * accordingly. After this update, P will pass the tests | |
201 | * in Step 6. A SyncAck is generated if necessary in | |
202 | * Step 15 * / | |
203 | * Update S.GSR, S.SWL, S.SWH | |
204 | * Otherwise, | |
205 | * Drop packet and return | |
206 | */ | |
8109b02b | 207 | if (dh->dccph_type == DCCP_PKT_SYNC || |
7c657876 | 208 | dh->dccph_type == DCCP_PKT_SYNCACK) { |
cbe1f5f8 GR |
209 | if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && |
210 | dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) | |
211 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
212 | else |
213 | return -1; | |
e92ae93a | 214 | } |
c9eaf173 | 215 | |
7c657876 ACM |
216 | /* |
217 | * Step 6: Check sequence numbers | |
218 | * Let LSWL = S.SWL and LAWL = S.AWL | |
219 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
220 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
221 | * If LSWL <= P.seqno <= S.SWH | |
222 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
223 | * Update S.GSR, S.SWL, S.SWH | |
224 | * If P.type != Sync, | |
225 | * Update S.GAR | |
7c657876 | 226 | */ |
e92ae93a ACM |
227 | lswl = dp->dccps_swl; |
228 | lawl = dp->dccps_awl; | |
229 | ||
230 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
231 | dh->dccph_type == DCCP_PKT_CLOSE || |
232 | dh->dccph_type == DCCP_PKT_RESET) { | |
cbe1f5f8 | 233 | lswl = ADD48(dp->dccps_gsr, 1); |
7c657876 ACM |
234 | lawl = dp->dccps_gar; |
235 | } | |
236 | ||
cbe1f5f8 GR |
237 | if (between48(seqno, lswl, dp->dccps_swh) && |
238 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || | |
239 | between48(ackno, lawl, dp->dccps_awh))) { | |
240 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
241 | |
242 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
cbe1f5f8 GR |
243 | (ackno != DCCP_PKT_WITHOUT_ACK_SEQ)) |
244 | dp->dccps_gar = ackno; | |
7c657876 | 245 | } else { |
a94f0f97 GR |
246 | unsigned long now = jiffies; |
247 | /* | |
248 | * Step 6: Check sequence numbers | |
249 | * Otherwise, | |
250 | * If P.type == Reset, | |
251 | * Send Sync packet acknowledging S.GSR | |
252 | * Otherwise, | |
253 | * Send Sync packet acknowledging P.seqno | |
254 | * Drop packet and return | |
255 | * | |
256 | * These Syncs are rate-limited as per RFC 4340, 7.5.4: | |
257 | * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. | |
258 | */ | |
259 | if (time_before(now, (dp->dccps_rate_last + | |
260 | sysctl_dccp_sync_ratelimit))) | |
261 | return 0; | |
262 | ||
59348b19 GR |
263 | DCCP_WARN("DCCP: Step 6 failed for %s packet, " |
264 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " | |
265 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
266 | "sending SYNC...\n", dccp_packet_name(dh->dccph_type), | |
cbe1f5f8 | 267 | (unsigned long long) lswl, (unsigned long long) seqno, |
59348b19 | 268 | (unsigned long long) dp->dccps_swh, |
cbe1f5f8 GR |
269 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
270 | : "exists", | |
271 | (unsigned long long) lawl, (unsigned long long) ackno, | |
59348b19 | 272 | (unsigned long long) dp->dccps_awh); |
a94f0f97 GR |
273 | |
274 | dp->dccps_rate_last = now; | |
275 | ||
e155d769 GR |
276 | if (dh->dccph_type == DCCP_PKT_RESET) |
277 | seqno = dp->dccps_gsr; | |
cbe1f5f8 | 278 | dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
7c657876 ACM |
279 | return -1; |
280 | } | |
281 | ||
282 | return 0; | |
283 | } | |
284 | ||
c25a18ba ACM |
285 | static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
286 | const struct dccp_hdr *dh, const unsigned len) | |
7c657876 ACM |
287 | { |
288 | struct dccp_sock *dp = dccp_sk(sk); | |
289 | ||
7c657876 ACM |
290 | switch (dccp_hdr(skb)->dccph_type) { |
291 | case DCCP_PKT_DATAACK: | |
292 | case DCCP_PKT_DATA: | |
293 | /* | |
8e8c71f1 GR |
294 | * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when |
295 | * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening" | |
296 | * - sk_receive_queue is full, use Code 2, "Receive Buffer" | |
7c657876 | 297 | */ |
69567d0b | 298 | dccp_enqueue_skb(sk, skb); |
7c657876 ACM |
299 | return 0; |
300 | case DCCP_PKT_ACK: | |
301 | goto discard; | |
302 | case DCCP_PKT_RESET: | |
303 | /* | |
304 | * Step 9: Process Reset | |
305 | * If P.type == Reset, | |
306 | * Tear down connection | |
307 | * S.state := TIMEWAIT | |
308 | * Set TIMEWAIT timer | |
309 | * Drop packet and return | |
d8ef2c29 GR |
310 | */ |
311 | dccp_rcv_reset(sk, skb); | |
7c657876 ACM |
312 | return 0; |
313 | case DCCP_PKT_CLOSEREQ: | |
0c869620 GR |
314 | if (dccp_rcv_closereq(sk, skb)) |
315 | return 0; | |
7c657876 ACM |
316 | goto discard; |
317 | case DCCP_PKT_CLOSE: | |
0c869620 GR |
318 | if (dccp_rcv_close(sk, skb)) |
319 | return 0; | |
320 | goto discard; | |
7c657876 | 321 | case DCCP_PKT_REQUEST: |
8109b02b ACM |
322 | /* Step 7 |
323 | * or (S.is_server and P.type == Response) | |
7c657876 ACM |
324 | * or (S.is_client and P.type == Request) |
325 | * or (S.state >= OPEN and P.type == Request | |
326 | * and P.seqno >= S.OSR) | |
327 | * or (S.state >= OPEN and P.type == Response | |
328 | * and P.seqno >= S.OSR) | |
329 | * or (S.state == RESPOND and P.type == Data), | |
330 | * Send Sync packet acknowledging P.seqno | |
331 | * Drop packet and return | |
332 | */ | |
333 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
334 | goto send_sync; | |
335 | goto check_seq; | |
336 | case DCCP_PKT_RESPONSE: | |
337 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
338 | goto send_sync; | |
339 | check_seq: | |
8d13bf9a GR |
340 | if (dccp_delta_seqno(dp->dccps_osr, |
341 | DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { | |
7c657876 | 342 | send_sync: |
e92ae93a ACM |
343 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
344 | DCCP_PKT_SYNC); | |
7c657876 ACM |
345 | } |
346 | break; | |
e92ae93a ACM |
347 | case DCCP_PKT_SYNC: |
348 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
349 | DCCP_PKT_SYNCACK); | |
350 | /* | |
0e64e94e | 351 | * From RFC 4340, sec. 5.7 |
e92ae93a ACM |
352 | * |
353 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
354 | * MAY have non-zero-length application data areas, whose | |
0e64e94e | 355 | * contents receivers MUST ignore. |
e92ae93a ACM |
356 | */ |
357 | goto discard; | |
7c657876 ACM |
358 | } |
359 | ||
360 | DCCP_INC_STATS_BH(DCCP_MIB_INERRS); | |
361 | discard: | |
362 | __kfree_skb(skb); | |
363 | return 0; | |
364 | } | |
365 | ||
709dd3aa AB |
366 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
367 | const struct dccp_hdr *dh, const unsigned len) | |
368 | { | |
709dd3aa AB |
369 | if (dccp_check_seqno(sk, skb)) |
370 | goto discard; | |
371 | ||
8b819412 | 372 | if (dccp_parse_options(sk, NULL, skb)) |
ba1a6c7b | 373 | return 1; |
709dd3aa | 374 | |
283fb4a5 | 375 | dccp_handle_ackvec_processing(sk, skb); |
8e8c71f1 | 376 | dccp_deliver_input_to_ccids(sk, skb); |
709dd3aa AB |
377 | |
378 | return __dccp_rcv_established(sk, skb, dh, len); | |
379 | discard: | |
380 | __kfree_skb(skb); | |
381 | return 0; | |
382 | } | |
383 | ||
f21e68ca ACM |
384 | EXPORT_SYMBOL_GPL(dccp_rcv_established); |
385 | ||
7c657876 ACM |
386 | static int dccp_rcv_request_sent_state_process(struct sock *sk, |
387 | struct sk_buff *skb, | |
388 | const struct dccp_hdr *dh, | |
389 | const unsigned len) | |
390 | { | |
8109b02b | 391 | /* |
7c657876 ACM |
392 | * Step 4: Prepare sequence numbers in REQUEST |
393 | * If S.state == REQUEST, | |
394 | * If (P.type == Response or P.type == Reset) | |
395 | * and S.AWL <= P.ackno <= S.AWH, | |
396 | * / * Set sequence number variables corresponding to the | |
397 | * other endpoint, so P will pass the tests in Step 6 * / | |
398 | * Set S.GSR, S.ISR, S.SWL, S.SWH | |
399 | * / * Response processing continues in Step 10; Reset | |
400 | * processing continues in Step 9 * / | |
401 | */ | |
402 | if (dh->dccph_type == DCCP_PKT_RESPONSE) { | |
403 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
404 | struct dccp_sock *dp = dccp_sk(sk); | |
3393da82 | 405 | long tstamp = dccp_timestamp(); |
7c657876 | 406 | |
7690af3f ACM |
407 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
408 | dp->dccps_awl, dp->dccps_awh)) { | |
409 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
410 | "P.ackno=%llu, S.AWH=%llu \n", | |
411 | (unsigned long long)dp->dccps_awl, | |
412 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
413 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
414 | goto out_invalid_packet; |
415 | } | |
9e377202 | 416 | |
c49b2272 GR |
417 | /* |
418 | * If option processing (Step 8) failed, return 1 here so that | |
419 | * dccp_v4_do_rcv() sends a Reset. The Reset code depends on | |
420 | * the option type and is set in dccp_parse_options(). | |
421 | */ | |
8b819412 | 422 | if (dccp_parse_options(sk, NULL, skb)) |
c49b2272 | 423 | return 1; |
afe00251 | 424 | |
3393da82 GR |
425 | /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ |
426 | if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) | |
427 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - | |
428 | dp->dccps_options_received.dccpor_timestamp_echo)); | |
89560b53 | 429 | |
d28934ad GR |
430 | /* Stop the REQUEST timer */ |
431 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
432 | WARN_ON(sk->sk_send_head == NULL); | |
433 | kfree_skb(sk->sk_send_head); | |
434 | sk->sk_send_head = NULL; | |
435 | ||
03ace394 | 436 | /* |
bfbddd08 GR |
437 | * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect |
438 | * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH | |
439 | * is done as part of activating the feature values below, since | |
440 | * these settings depend on the local/remote Sequence Window | |
441 | * features, which were undefined or not confirmed until now. | |
03ace394 | 442 | */ |
bfbddd08 | 443 | dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; |
7c657876 | 444 | |
d83d8461 | 445 | dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
7c657876 ACM |
446 | |
447 | /* | |
448 | * Step 10: Process REQUEST state (second part) | |
449 | * If S.state == REQUEST, | |
7690af3f ACM |
450 | * / * If we get here, P is a valid Response from the |
451 | * server (see Step 4), and we should move to | |
452 | * PARTOPEN state. PARTOPEN means send an Ack, | |
453 | * don't send Data packets, retransmit Acks | |
454 | * periodically, and always include any Init Cookie | |
455 | * from the Response * / | |
7c657876 ACM |
456 | * S.state := PARTOPEN |
457 | * Set PARTOPEN timer | |
8109b02b | 458 | * Continue with S.state == PARTOPEN |
7690af3f ACM |
459 | * / * Step 12 will send the Ack completing the |
460 | * three-way handshake * / | |
7c657876 ACM |
461 | */ |
462 | dccp_set_state(sk, DCCP_PARTOPEN); | |
463 | ||
c49b2272 GR |
464 | /* |
465 | * If feature negotiation was successful, activate features now; | |
466 | * an activation failure means that this host could not activate | |
467 | * one ore more features (e.g. insufficient memory), which would | |
468 | * leave at least one feature in an undefined state. | |
469 | */ | |
470 | if (dccp_feat_activate_values(sk, &dp->dccps_featneg)) | |
471 | goto unable_to_proceed; | |
472 | ||
7c657876 | 473 | /* Make sure socket is routed, for correct metrics. */ |
57cca05a | 474 | icsk->icsk_af_ops->rebuild_header(sk); |
7c657876 ACM |
475 | |
476 | if (!sock_flag(sk, SOCK_DEAD)) { | |
477 | sk->sk_state_change(sk); | |
8d8ad9d7 | 478 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
7c657876 ACM |
479 | } |
480 | ||
481 | if (sk->sk_write_pending || icsk->icsk_ack.pingpong || | |
482 | icsk->icsk_accept_queue.rskq_defer_accept) { | |
483 | /* Save one ACK. Data will be ready after | |
484 | * several ticks, if write_pending is set. | |
485 | * | |
486 | * It may be deleted, but with this feature tcpdumps | |
487 | * look so _wonderfully_ clever, that I was not able | |
488 | * to stand against the temptation 8) --ANK | |
489 | */ | |
490 | /* | |
491 | * OK, in DCCP we can as well do a similar trick, its | |
492 | * even in the draft, but there is no need for us to | |
493 | * schedule an ack here, as dccp_sendmsg does this for | |
494 | * us, also stated in the draft. -acme | |
495 | */ | |
496 | __kfree_skb(skb); | |
497 | return 0; | |
8109b02b | 498 | } |
7c657876 ACM |
499 | dccp_send_ack(sk); |
500 | return -1; | |
501 | } | |
502 | ||
503 | out_invalid_packet: | |
0c10c5d9 ACM |
504 | /* dccp_v4_do_rcv will send a reset */ |
505 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
8109b02b | 506 | return 1; |
c49b2272 GR |
507 | |
508 | unable_to_proceed: | |
509 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED; | |
510 | /* | |
511 | * We mark this socket as no longer usable, so that the loop in | |
512 | * dccp_sendmsg() terminates and the application gets notified. | |
513 | */ | |
514 | dccp_set_state(sk, DCCP_CLOSED); | |
515 | sk->sk_err = ECOMM; | |
516 | return 1; | |
7c657876 ACM |
517 | } |
518 | ||
519 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
520 | struct sk_buff *skb, | |
521 | const struct dccp_hdr *dh, | |
522 | const unsigned len) | |
523 | { | |
524 | int queued = 0; | |
525 | ||
526 | switch (dh->dccph_type) { | |
527 | case DCCP_PKT_RESET: | |
528 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
529 | break; | |
2a9bc9bb ACM |
530 | case DCCP_PKT_DATA: |
531 | if (sk->sk_state == DCCP_RESPOND) | |
532 | break; | |
7c657876 ACM |
533 | case DCCP_PKT_DATAACK: |
534 | case DCCP_PKT_ACK: | |
535 | /* | |
7690af3f ACM |
536 | * FIXME: we should be reseting the PARTOPEN (DELACK) timer |
537 | * here but only if we haven't used the DELACK timer for | |
538 | * something else, like sending a delayed ack for a TIMESTAMP | |
539 | * echo, etc, for now were not clearing it, sending an extra | |
540 | * ACK when there is nothing else to do in DELACK is not a big | |
541 | * deal after all. | |
7c657876 ACM |
542 | */ |
543 | ||
544 | /* Stop the PARTOPEN timer */ | |
545 | if (sk->sk_state == DCCP_PARTOPEN) | |
546 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
547 | ||
548 | dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
549 | dccp_set_state(sk, DCCP_OPEN); | |
550 | ||
2a9bc9bb ACM |
551 | if (dh->dccph_type == DCCP_PKT_DATAACK || |
552 | dh->dccph_type == DCCP_PKT_DATA) { | |
709dd3aa | 553 | __dccp_rcv_established(sk, skb, dh, len); |
7690af3f | 554 | queued = 1; /* packet was queued |
709dd3aa | 555 | (by __dccp_rcv_established) */ |
7c657876 ACM |
556 | } |
557 | break; | |
558 | } | |
559 | ||
560 | return queued; | |
561 | } | |
562 | ||
563 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
564 | struct dccp_hdr *dh, unsigned len) | |
565 | { | |
566 | struct dccp_sock *dp = dccp_sk(sk); | |
0c10c5d9 | 567 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
7c657876 ACM |
568 | const int old_state = sk->sk_state; |
569 | int queued = 0; | |
570 | ||
8649b0d4 ACM |
571 | /* |
572 | * Step 3: Process LISTEN state | |
8649b0d4 ACM |
573 | * |
574 | * If S.state == LISTEN, | |
d83ca5ac GR |
575 | * If P.type == Request or P contains a valid Init Cookie option, |
576 | * (* Must scan the packet's options to check for Init | |
577 | * Cookies. Only Init Cookies are processed here, | |
578 | * however; other options are processed in Step 8. This | |
579 | * scan need only be performed if the endpoint uses Init | |
580 | * Cookies *) | |
581 | * (* Generate a new socket and switch to that socket *) | |
582 | * Set S := new socket for this port pair | |
583 | * S.state = RESPOND | |
584 | * Choose S.ISS (initial seqno) or set from Init Cookies | |
585 | * Initialize S.GAR := S.ISS | |
586 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init | |
587 | * Cookies Continue with S.state == RESPOND | |
588 | * (* A Response packet will be generated in Step 11 *) | |
589 | * Otherwise, | |
590 | * Generate Reset(No Connection) unless P.type == Reset | |
591 | * Drop packet and return | |
8649b0d4 ACM |
592 | */ |
593 | if (sk->sk_state == DCCP_LISTEN) { | |
594 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
57cca05a ACM |
595 | if (inet_csk(sk)->icsk_af_ops->conn_request(sk, |
596 | skb) < 0) | |
8649b0d4 | 597 | return 1; |
8649b0d4 ACM |
598 | goto discard; |
599 | } | |
600 | if (dh->dccph_type == DCCP_PKT_RESET) | |
601 | goto discard; | |
602 | ||
0c10c5d9 ACM |
603 | /* Caller (dccp_v4_do_rcv) will send Reset */ |
604 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
8649b0d4 ACM |
605 | return 1; |
606 | } | |
607 | ||
c49b2272 | 608 | if (sk->sk_state != DCCP_REQUESTING && sk->sk_state != DCCP_RESPOND) { |
7c657876 ACM |
609 | if (dccp_check_seqno(sk, skb)) |
610 | goto discard; | |
611 | ||
612 | /* | |
613 | * Step 8: Process options and mark acknowledgeable | |
614 | */ | |
8b819412 | 615 | if (dccp_parse_options(sk, NULL, skb)) |
ba1a6c7b | 616 | return 1; |
7c657876 | 617 | |
283fb4a5 | 618 | dccp_handle_ackvec_processing(sk, skb); |
8e8c71f1 | 619 | dccp_deliver_input_to_ccids(sk, skb); |
7c657876 ACM |
620 | } |
621 | ||
622 | /* | |
623 | * Step 9: Process Reset | |
624 | * If P.type == Reset, | |
625 | * Tear down connection | |
626 | * S.state := TIMEWAIT | |
627 | * Set TIMEWAIT timer | |
628 | * Drop packet and return | |
629 | */ | |
630 | if (dh->dccph_type == DCCP_PKT_RESET) { | |
d8ef2c29 | 631 | dccp_rcv_reset(sk, skb); |
7c657876 ACM |
632 | return 0; |
633 | /* | |
634 | * Step 7: Check for unexpected packet types | |
3159afe0 | 635 | * If (S.is_server and P.type == Response) |
7c657876 ACM |
636 | * or (S.is_client and P.type == Request) |
637 | * or (S.state == RESPOND and P.type == Data), | |
638 | * Send Sync packet acknowledging P.seqno | |
639 | * Drop packet and return | |
640 | */ | |
641 | } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
3159afe0 | 642 | dh->dccph_type == DCCP_PKT_RESPONSE) || |
7c657876 ACM |
643 | (dp->dccps_role == DCCP_ROLE_CLIENT && |
644 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
7690af3f ACM |
645 | (sk->sk_state == DCCP_RESPOND && |
646 | dh->dccph_type == DCCP_PKT_DATA)) { | |
0c10c5d9 | 647 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 | 648 | goto discard; |
7ad07e7c | 649 | } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { |
0c869620 GR |
650 | if (dccp_rcv_closereq(sk, skb)) |
651 | return 0; | |
7ad07e7c ACM |
652 | goto discard; |
653 | } else if (dh->dccph_type == DCCP_PKT_CLOSE) { | |
0c869620 GR |
654 | if (dccp_rcv_close(sk, skb)) |
655 | return 0; | |
656 | goto discard; | |
7c657876 ACM |
657 | } |
658 | ||
659 | switch (sk->sk_state) { | |
660 | case DCCP_CLOSED: | |
0c10c5d9 | 661 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; |
7c657876 ACM |
662 | return 1; |
663 | ||
7c657876 | 664 | case DCCP_REQUESTING: |
7c657876 ACM |
665 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); |
666 | if (queued >= 0) | |
667 | return queued; | |
668 | ||
669 | __kfree_skb(skb); | |
670 | return 0; | |
671 | ||
672 | case DCCP_RESPOND: | |
673 | case DCCP_PARTOPEN: | |
7690af3f ACM |
674 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
675 | dh, len); | |
7c657876 ACM |
676 | break; |
677 | } | |
678 | ||
7690af3f ACM |
679 | if (dh->dccph_type == DCCP_PKT_ACK || |
680 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
681 | switch (old_state) { |
682 | case DCCP_PARTOPEN: | |
683 | sk->sk_state_change(sk); | |
8d8ad9d7 | 684 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
7c657876 ACM |
685 | break; |
686 | } | |
08831700 GR |
687 | } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
688 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); | |
689 | goto discard; | |
7c657876 ACM |
690 | } |
691 | ||
8109b02b | 692 | if (!queued) { |
7c657876 ACM |
693 | discard: |
694 | __kfree_skb(skb); | |
695 | } | |
696 | return 0; | |
697 | } | |
f21e68ca ACM |
698 | |
699 | EXPORT_SYMBOL_GPL(dccp_rcv_state_process); | |
4712a792 GR |
700 | |
701 | /** | |
3393da82 GR |
702 | * dccp_sample_rtt - Validate and finalise computation of RTT sample |
703 | * @delta: number of microseconds between packet and acknowledgment | |
704 | * The routine is kept generic to work in different contexts. It should be | |
705 | * called immediately when the ACK used for the RTT sample arrives. | |
4712a792 | 706 | */ |
3393da82 | 707 | u32 dccp_sample_rtt(struct sock *sk, long delta) |
4712a792 | 708 | { |
3393da82 GR |
709 | /* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
710 | delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; | |
4712a792 GR |
711 | |
712 | if (unlikely(delta <= 0)) { | |
3393da82 | 713 | DCCP_WARN("unusable RTT sample %ld, using min\n", delta); |
4712a792 GR |
714 | return DCCP_SANE_RTT_MIN; |
715 | } | |
3393da82 GR |
716 | if (unlikely(delta > DCCP_SANE_RTT_MAX)) { |
717 | DCCP_WARN("RTT sample %ld too large, using max\n", delta); | |
4712a792 GR |
718 | return DCCP_SANE_RTT_MAX; |
719 | } | |
720 | ||
721 | return delta; | |
722 | } | |
723 | ||
724 | EXPORT_SYMBOL_GPL(dccp_sample_rtt); |