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 | ||
d8ef2c29 GR |
61 | static u8 dccp_reset_code_convert(const u8 code) |
62 | { | |
63 | const u8 error_code[] = { | |
64 | [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */ | |
65 | [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */ | |
66 | [DCCP_RESET_CODE_ABORTED] = ECONNRESET, | |
67 | ||
68 | [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED, | |
69 | [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED, | |
70 | [DCCP_RESET_CODE_TOO_BUSY] = EUSERS, | |
71 | [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT, | |
72 | ||
73 | [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG, | |
74 | [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR, | |
75 | [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC, | |
76 | [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ, | |
77 | [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP, | |
78 | }; | |
79 | ||
80 | return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code]; | |
81 | } | |
82 | ||
83 | static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb) | |
84 | { | |
85 | u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code); | |
86 | ||
87 | sk->sk_err = err; | |
88 | ||
89 | /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */ | |
90 | dccp_fin(sk, skb); | |
91 | ||
92 | if (err && !sock_flag(sk, SOCK_DEAD)) | |
93 | sk_wake_async(sk, 0, POLL_ERR); | |
94 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); | |
95 | } | |
96 | ||
c25a18ba | 97 | static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
98 | { |
99 | struct dccp_sock *dp = dccp_sk(sk); | |
100 | ||
a4bf3902 | 101 | if (dccp_msk(sk)->dccpms_send_ack_vector) |
ae31c339 ACM |
102 | dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk, |
103 | DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
7c657876 ACM |
104 | } |
105 | ||
8e8c71f1 GR |
106 | static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb) |
107 | { | |
108 | const struct dccp_sock *dp = dccp_sk(sk); | |
109 | ||
110 | /* Don't deliver to RX CCID when node has shut down read end. */ | |
111 | if (!(sk->sk_shutdown & RCV_SHUTDOWN)) | |
112 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); | |
113 | /* | |
114 | * Until the TX queue has been drained, we can not honour SHUT_WR, since | |
115 | * we need received feedback as input to adjust congestion control. | |
116 | */ | |
117 | if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN)) | |
118 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
119 | } | |
120 | ||
7c657876 ACM |
121 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) |
122 | { | |
123 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
124 | struct dccp_sock *dp = dccp_sk(sk); | |
cbe1f5f8 GR |
125 | u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
126 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
7c657876 ACM |
127 | |
128 | /* | |
129 | * Step 5: Prepare sequence numbers for Sync | |
130 | * If P.type == Sync or P.type == SyncAck, | |
131 | * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, | |
132 | * / * P is valid, so update sequence number variables | |
133 | * accordingly. After this update, P will pass the tests | |
134 | * in Step 6. A SyncAck is generated if necessary in | |
135 | * Step 15 * / | |
136 | * Update S.GSR, S.SWL, S.SWH | |
137 | * Otherwise, | |
138 | * Drop packet and return | |
139 | */ | |
8109b02b | 140 | if (dh->dccph_type == DCCP_PKT_SYNC || |
7c657876 | 141 | dh->dccph_type == DCCP_PKT_SYNCACK) { |
cbe1f5f8 GR |
142 | if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && |
143 | dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) | |
144 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
145 | else |
146 | return -1; | |
e92ae93a | 147 | } |
c9eaf173 | 148 | |
7c657876 ACM |
149 | /* |
150 | * Step 6: Check sequence numbers | |
151 | * Let LSWL = S.SWL and LAWL = S.AWL | |
152 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
153 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
154 | * If LSWL <= P.seqno <= S.SWH | |
155 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
156 | * Update S.GSR, S.SWL, S.SWH | |
157 | * If P.type != Sync, | |
158 | * Update S.GAR | |
7c657876 | 159 | */ |
e92ae93a ACM |
160 | lswl = dp->dccps_swl; |
161 | lawl = dp->dccps_awl; | |
162 | ||
163 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
164 | dh->dccph_type == DCCP_PKT_CLOSE || |
165 | dh->dccph_type == DCCP_PKT_RESET) { | |
cbe1f5f8 | 166 | lswl = ADD48(dp->dccps_gsr, 1); |
7c657876 ACM |
167 | lawl = dp->dccps_gar; |
168 | } | |
169 | ||
cbe1f5f8 GR |
170 | if (between48(seqno, lswl, dp->dccps_swh) && |
171 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || | |
172 | between48(ackno, lawl, dp->dccps_awh))) { | |
173 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
174 | |
175 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
cbe1f5f8 GR |
176 | (ackno != DCCP_PKT_WITHOUT_ACK_SEQ)) |
177 | dp->dccps_gar = ackno; | |
7c657876 | 178 | } else { |
a94f0f97 GR |
179 | unsigned long now = jiffies; |
180 | /* | |
181 | * Step 6: Check sequence numbers | |
182 | * Otherwise, | |
183 | * If P.type == Reset, | |
184 | * Send Sync packet acknowledging S.GSR | |
185 | * Otherwise, | |
186 | * Send Sync packet acknowledging P.seqno | |
187 | * Drop packet and return | |
188 | * | |
189 | * These Syncs are rate-limited as per RFC 4340, 7.5.4: | |
190 | * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. | |
191 | */ | |
192 | if (time_before(now, (dp->dccps_rate_last + | |
193 | sysctl_dccp_sync_ratelimit))) | |
194 | return 0; | |
195 | ||
59348b19 GR |
196 | DCCP_WARN("DCCP: Step 6 failed for %s packet, " |
197 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " | |
198 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
199 | "sending SYNC...\n", dccp_packet_name(dh->dccph_type), | |
cbe1f5f8 | 200 | (unsigned long long) lswl, (unsigned long long) seqno, |
59348b19 | 201 | (unsigned long long) dp->dccps_swh, |
cbe1f5f8 GR |
202 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
203 | : "exists", | |
204 | (unsigned long long) lawl, (unsigned long long) ackno, | |
59348b19 | 205 | (unsigned long long) dp->dccps_awh); |
a94f0f97 GR |
206 | |
207 | dp->dccps_rate_last = now; | |
208 | ||
e155d769 GR |
209 | if (dh->dccph_type == DCCP_PKT_RESET) |
210 | seqno = dp->dccps_gsr; | |
cbe1f5f8 | 211 | dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
7c657876 ACM |
212 | return -1; |
213 | } | |
214 | ||
215 | return 0; | |
216 | } | |
217 | ||
c25a18ba ACM |
218 | static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
219 | const struct dccp_hdr *dh, const unsigned len) | |
7c657876 ACM |
220 | { |
221 | struct dccp_sock *dp = dccp_sk(sk); | |
222 | ||
7c657876 ACM |
223 | switch (dccp_hdr(skb)->dccph_type) { |
224 | case DCCP_PKT_DATAACK: | |
225 | case DCCP_PKT_DATA: | |
226 | /* | |
8e8c71f1 GR |
227 | * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when |
228 | * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening" | |
229 | * - sk_receive_queue is full, use Code 2, "Receive Buffer" | |
7c657876 ACM |
230 | */ |
231 | __skb_pull(skb, dh->dccph_doff * 4); | |
232 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
233 | skb_set_owner_r(skb, sk); | |
234 | sk->sk_data_ready(sk, 0); | |
235 | return 0; | |
236 | case DCCP_PKT_ACK: | |
237 | goto discard; | |
238 | case DCCP_PKT_RESET: | |
239 | /* | |
240 | * Step 9: Process Reset | |
241 | * If P.type == Reset, | |
242 | * Tear down connection | |
243 | * S.state := TIMEWAIT | |
244 | * Set TIMEWAIT timer | |
245 | * Drop packet and return | |
d8ef2c29 GR |
246 | */ |
247 | dccp_rcv_reset(sk, skb); | |
7c657876 ACM |
248 | return 0; |
249 | case DCCP_PKT_CLOSEREQ: | |
250 | dccp_rcv_closereq(sk, skb); | |
251 | goto discard; | |
252 | case DCCP_PKT_CLOSE: | |
253 | dccp_rcv_close(sk, skb); | |
254 | return 0; | |
255 | case DCCP_PKT_REQUEST: | |
8109b02b ACM |
256 | /* Step 7 |
257 | * or (S.is_server and P.type == Response) | |
7c657876 ACM |
258 | * or (S.is_client and P.type == Request) |
259 | * or (S.state >= OPEN and P.type == Request | |
260 | * and P.seqno >= S.OSR) | |
261 | * or (S.state >= OPEN and P.type == Response | |
262 | * and P.seqno >= S.OSR) | |
263 | * or (S.state == RESPOND and P.type == Data), | |
264 | * Send Sync packet acknowledging P.seqno | |
265 | * Drop packet and return | |
266 | */ | |
267 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
268 | goto send_sync; | |
269 | goto check_seq; | |
270 | case DCCP_PKT_RESPONSE: | |
271 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
272 | goto send_sync; | |
273 | check_seq: | |
8d13bf9a GR |
274 | if (dccp_delta_seqno(dp->dccps_osr, |
275 | DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { | |
7c657876 | 276 | send_sync: |
e92ae93a ACM |
277 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
278 | DCCP_PKT_SYNC); | |
7c657876 ACM |
279 | } |
280 | break; | |
e92ae93a ACM |
281 | case DCCP_PKT_SYNC: |
282 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
283 | DCCP_PKT_SYNCACK); | |
284 | /* | |
0e64e94e | 285 | * From RFC 4340, sec. 5.7 |
e92ae93a ACM |
286 | * |
287 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
288 | * MAY have non-zero-length application data areas, whose | |
0e64e94e | 289 | * contents receivers MUST ignore. |
e92ae93a ACM |
290 | */ |
291 | goto discard; | |
7c657876 ACM |
292 | } |
293 | ||
294 | DCCP_INC_STATS_BH(DCCP_MIB_INERRS); | |
295 | discard: | |
296 | __kfree_skb(skb); | |
297 | return 0; | |
298 | } | |
299 | ||
709dd3aa AB |
300 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
301 | const struct dccp_hdr *dh, const unsigned len) | |
302 | { | |
303 | struct dccp_sock *dp = dccp_sk(sk); | |
304 | ||
305 | if (dccp_check_seqno(sk, skb)) | |
306 | goto discard; | |
307 | ||
308 | if (dccp_parse_options(sk, skb)) | |
309 | goto discard; | |
310 | ||
311 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
312 | dccp_event_ack_recv(sk, skb); | |
313 | ||
a4bf3902 | 314 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
709dd3aa AB |
315 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
316 | DCCP_SKB_CB(skb)->dccpd_seq, | |
317 | DCCP_ACKVEC_STATE_RECEIVED)) | |
318 | goto discard; | |
8e8c71f1 | 319 | dccp_deliver_input_to_ccids(sk, skb); |
709dd3aa AB |
320 | |
321 | return __dccp_rcv_established(sk, skb, dh, len); | |
322 | discard: | |
323 | __kfree_skb(skb); | |
324 | return 0; | |
325 | } | |
326 | ||
f21e68ca ACM |
327 | EXPORT_SYMBOL_GPL(dccp_rcv_established); |
328 | ||
7c657876 ACM |
329 | static int dccp_rcv_request_sent_state_process(struct sock *sk, |
330 | struct sk_buff *skb, | |
331 | const struct dccp_hdr *dh, | |
332 | const unsigned len) | |
333 | { | |
8109b02b | 334 | /* |
7c657876 ACM |
335 | * Step 4: Prepare sequence numbers in REQUEST |
336 | * If S.state == REQUEST, | |
337 | * If (P.type == Response or P.type == Reset) | |
338 | * and S.AWL <= P.ackno <= S.AWH, | |
339 | * / * Set sequence number variables corresponding to the | |
340 | * other endpoint, so P will pass the tests in Step 6 * / | |
341 | * Set S.GSR, S.ISR, S.SWL, S.SWH | |
342 | * / * Response processing continues in Step 10; Reset | |
343 | * processing continues in Step 9 * / | |
344 | */ | |
345 | if (dh->dccph_type == DCCP_PKT_RESPONSE) { | |
346 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
347 | struct dccp_sock *dp = dccp_sk(sk); | |
3393da82 | 348 | long tstamp = dccp_timestamp(); |
7c657876 ACM |
349 | |
350 | /* Stop the REQUEST timer */ | |
351 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
352 | BUG_TRAP(sk->sk_send_head != NULL); | |
353 | __kfree_skb(sk->sk_send_head); | |
354 | sk->sk_send_head = NULL; | |
355 | ||
7690af3f ACM |
356 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
357 | dp->dccps_awl, dp->dccps_awh)) { | |
358 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
359 | "P.ackno=%llu, S.AWH=%llu \n", | |
360 | (unsigned long long)dp->dccps_awl, | |
361 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
362 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
363 | goto out_invalid_packet; |
364 | } | |
9e377202 | 365 | |
afe00251 AB |
366 | if (dccp_parse_options(sk, skb)) |
367 | goto out_invalid_packet; | |
368 | ||
3393da82 GR |
369 | /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ |
370 | if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) | |
371 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - | |
372 | dp->dccps_options_received.dccpor_timestamp_echo)); | |
89560b53 | 373 | |
c9eaf173 YH |
374 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
375 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, | |
376 | DCCP_SKB_CB(skb)->dccpd_seq, | |
377 | DCCP_ACKVEC_STATE_RECEIVED)) | |
378 | goto out_invalid_packet; /* FIXME: change error code */ | |
7c657876 ACM |
379 | |
380 | dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; | |
03ace394 ACM |
381 | dccp_update_gsr(sk, dp->dccps_isr); |
382 | /* | |
383 | * SWL and AWL are initially adjusted so that they are not less than | |
384 | * the initial Sequence Numbers received and sent, respectively: | |
385 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
386 | * AWL := max(GSS - W' + 1, ISS). | |
387 | * These adjustments MUST be applied only at the beginning of the | |
388 | * connection. | |
389 | * | |
390 | * AWL was adjusted in dccp_v4_connect -acme | |
391 | */ | |
392 | dccp_set_seqno(&dp->dccps_swl, | |
393 | max48(dp->dccps_swl, dp->dccps_isr)); | |
7c657876 | 394 | |
d83d8461 | 395 | dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
7c657876 ACM |
396 | |
397 | /* | |
398 | * Step 10: Process REQUEST state (second part) | |
399 | * If S.state == REQUEST, | |
7690af3f ACM |
400 | * / * If we get here, P is a valid Response from the |
401 | * server (see Step 4), and we should move to | |
402 | * PARTOPEN state. PARTOPEN means send an Ack, | |
403 | * don't send Data packets, retransmit Acks | |
404 | * periodically, and always include any Init Cookie | |
405 | * from the Response * / | |
7c657876 ACM |
406 | * S.state := PARTOPEN |
407 | * Set PARTOPEN timer | |
8109b02b | 408 | * Continue with S.state == PARTOPEN |
7690af3f ACM |
409 | * / * Step 12 will send the Ack completing the |
410 | * three-way handshake * / | |
7c657876 ACM |
411 | */ |
412 | dccp_set_state(sk, DCCP_PARTOPEN); | |
413 | ||
414 | /* Make sure socket is routed, for correct metrics. */ | |
57cca05a | 415 | icsk->icsk_af_ops->rebuild_header(sk); |
7c657876 ACM |
416 | |
417 | if (!sock_flag(sk, SOCK_DEAD)) { | |
418 | sk->sk_state_change(sk); | |
419 | sk_wake_async(sk, 0, POLL_OUT); | |
420 | } | |
421 | ||
422 | if (sk->sk_write_pending || icsk->icsk_ack.pingpong || | |
423 | icsk->icsk_accept_queue.rskq_defer_accept) { | |
424 | /* Save one ACK. Data will be ready after | |
425 | * several ticks, if write_pending is set. | |
426 | * | |
427 | * It may be deleted, but with this feature tcpdumps | |
428 | * look so _wonderfully_ clever, that I was not able | |
429 | * to stand against the temptation 8) --ANK | |
430 | */ | |
431 | /* | |
432 | * OK, in DCCP we can as well do a similar trick, its | |
433 | * even in the draft, but there is no need for us to | |
434 | * schedule an ack here, as dccp_sendmsg does this for | |
435 | * us, also stated in the draft. -acme | |
436 | */ | |
437 | __kfree_skb(skb); | |
438 | return 0; | |
8109b02b | 439 | } |
7c657876 ACM |
440 | dccp_send_ack(sk); |
441 | return -1; | |
442 | } | |
443 | ||
444 | out_invalid_packet: | |
0c10c5d9 ACM |
445 | /* dccp_v4_do_rcv will send a reset */ |
446 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
8109b02b | 447 | return 1; |
7c657876 ACM |
448 | } |
449 | ||
450 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
451 | struct sk_buff *skb, | |
452 | const struct dccp_hdr *dh, | |
453 | const unsigned len) | |
454 | { | |
455 | int queued = 0; | |
456 | ||
457 | switch (dh->dccph_type) { | |
458 | case DCCP_PKT_RESET: | |
459 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
460 | break; | |
2a9bc9bb ACM |
461 | case DCCP_PKT_DATA: |
462 | if (sk->sk_state == DCCP_RESPOND) | |
463 | break; | |
7c657876 ACM |
464 | case DCCP_PKT_DATAACK: |
465 | case DCCP_PKT_ACK: | |
466 | /* | |
7690af3f ACM |
467 | * FIXME: we should be reseting the PARTOPEN (DELACK) timer |
468 | * here but only if we haven't used the DELACK timer for | |
469 | * something else, like sending a delayed ack for a TIMESTAMP | |
470 | * echo, etc, for now were not clearing it, sending an extra | |
471 | * ACK when there is nothing else to do in DELACK is not a big | |
472 | * deal after all. | |
7c657876 ACM |
473 | */ |
474 | ||
475 | /* Stop the PARTOPEN timer */ | |
476 | if (sk->sk_state == DCCP_PARTOPEN) | |
477 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
478 | ||
479 | dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
480 | dccp_set_state(sk, DCCP_OPEN); | |
481 | ||
2a9bc9bb ACM |
482 | if (dh->dccph_type == DCCP_PKT_DATAACK || |
483 | dh->dccph_type == DCCP_PKT_DATA) { | |
709dd3aa | 484 | __dccp_rcv_established(sk, skb, dh, len); |
7690af3f | 485 | queued = 1; /* packet was queued |
709dd3aa | 486 | (by __dccp_rcv_established) */ |
7c657876 ACM |
487 | } |
488 | break; | |
489 | } | |
490 | ||
491 | return queued; | |
492 | } | |
493 | ||
494 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
495 | struct dccp_hdr *dh, unsigned len) | |
496 | { | |
497 | struct dccp_sock *dp = dccp_sk(sk); | |
0c10c5d9 | 498 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
7c657876 ACM |
499 | const int old_state = sk->sk_state; |
500 | int queued = 0; | |
501 | ||
8649b0d4 ACM |
502 | /* |
503 | * Step 3: Process LISTEN state | |
8649b0d4 ACM |
504 | * |
505 | * If S.state == LISTEN, | |
d83ca5ac GR |
506 | * If P.type == Request or P contains a valid Init Cookie option, |
507 | * (* Must scan the packet's options to check for Init | |
508 | * Cookies. Only Init Cookies are processed here, | |
509 | * however; other options are processed in Step 8. This | |
510 | * scan need only be performed if the endpoint uses Init | |
511 | * Cookies *) | |
512 | * (* Generate a new socket and switch to that socket *) | |
513 | * Set S := new socket for this port pair | |
514 | * S.state = RESPOND | |
515 | * Choose S.ISS (initial seqno) or set from Init Cookies | |
516 | * Initialize S.GAR := S.ISS | |
517 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init | |
518 | * Cookies Continue with S.state == RESPOND | |
519 | * (* A Response packet will be generated in Step 11 *) | |
520 | * Otherwise, | |
521 | * Generate Reset(No Connection) unless P.type == Reset | |
522 | * Drop packet and return | |
8649b0d4 ACM |
523 | */ |
524 | if (sk->sk_state == DCCP_LISTEN) { | |
525 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
57cca05a ACM |
526 | if (inet_csk(sk)->icsk_af_ops->conn_request(sk, |
527 | skb) < 0) | |
8649b0d4 ACM |
528 | return 1; |
529 | ||
530 | /* FIXME: do congestion control initialization */ | |
531 | goto discard; | |
532 | } | |
533 | if (dh->dccph_type == DCCP_PKT_RESET) | |
534 | goto discard; | |
535 | ||
0c10c5d9 ACM |
536 | /* Caller (dccp_v4_do_rcv) will send Reset */ |
537 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
8649b0d4 ACM |
538 | return 1; |
539 | } | |
540 | ||
541 | if (sk->sk_state != DCCP_REQUESTING) { | |
7c657876 ACM |
542 | if (dccp_check_seqno(sk, skb)) |
543 | goto discard; | |
544 | ||
545 | /* | |
546 | * Step 8: Process options and mark acknowledgeable | |
547 | */ | |
548 | if (dccp_parse_options(sk, skb)) | |
549 | goto discard; | |
550 | ||
0c10c5d9 | 551 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) |
7c657876 ACM |
552 | dccp_event_ack_recv(sk, skb); |
553 | ||
8109b02b | 554 | if (dccp_msk(sk)->dccpms_send_ack_vector && |
ae31c339 | 555 | dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, |
8109b02b ACM |
556 | DCCP_SKB_CB(skb)->dccpd_seq, |
557 | DCCP_ACKVEC_STATE_RECEIVED)) | |
558 | goto discard; | |
e84a9f5e | 559 | |
8e8c71f1 | 560 | dccp_deliver_input_to_ccids(sk, skb); |
7c657876 ACM |
561 | } |
562 | ||
563 | /* | |
564 | * Step 9: Process Reset | |
565 | * If P.type == Reset, | |
566 | * Tear down connection | |
567 | * S.state := TIMEWAIT | |
568 | * Set TIMEWAIT timer | |
569 | * Drop packet and return | |
570 | */ | |
571 | if (dh->dccph_type == DCCP_PKT_RESET) { | |
d8ef2c29 | 572 | dccp_rcv_reset(sk, skb); |
7c657876 ACM |
573 | return 0; |
574 | /* | |
575 | * Step 7: Check for unexpected packet types | |
576 | * If (S.is_server and P.type == CloseReq) | |
577 | * or (S.is_server and P.type == Response) | |
578 | * or (S.is_client and P.type == Request) | |
579 | * or (S.state == RESPOND and P.type == Data), | |
580 | * Send Sync packet acknowledging P.seqno | |
581 | * Drop packet and return | |
582 | */ | |
583 | } else if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
7690af3f ACM |
584 | (dh->dccph_type == DCCP_PKT_RESPONSE || |
585 | dh->dccph_type == DCCP_PKT_CLOSEREQ)) || | |
7c657876 ACM |
586 | (dp->dccps_role == DCCP_ROLE_CLIENT && |
587 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
7690af3f ACM |
588 | (sk->sk_state == DCCP_RESPOND && |
589 | dh->dccph_type == DCCP_PKT_DATA)) { | |
0c10c5d9 | 590 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); |
7c657876 | 591 | goto discard; |
7ad07e7c ACM |
592 | } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { |
593 | dccp_rcv_closereq(sk, skb); | |
594 | goto discard; | |
595 | } else if (dh->dccph_type == DCCP_PKT_CLOSE) { | |
596 | dccp_rcv_close(sk, skb); | |
597 | return 0; | |
7c657876 ACM |
598 | } |
599 | ||
600 | switch (sk->sk_state) { | |
601 | case DCCP_CLOSED: | |
0c10c5d9 | 602 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; |
7c657876 ACM |
603 | return 1; |
604 | ||
7c657876 ACM |
605 | case DCCP_REQUESTING: |
606 | /* FIXME: do congestion control initialization */ | |
607 | ||
608 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); | |
609 | if (queued >= 0) | |
610 | return queued; | |
611 | ||
612 | __kfree_skb(skb); | |
613 | return 0; | |
614 | ||
615 | case DCCP_RESPOND: | |
616 | case DCCP_PARTOPEN: | |
7690af3f ACM |
617 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
618 | dh, len); | |
7c657876 ACM |
619 | break; |
620 | } | |
621 | ||
7690af3f ACM |
622 | if (dh->dccph_type == DCCP_PKT_ACK || |
623 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
624 | switch (old_state) { |
625 | case DCCP_PARTOPEN: | |
626 | sk->sk_state_change(sk); | |
627 | sk_wake_async(sk, 0, POLL_OUT); | |
628 | break; | |
629 | } | |
08831700 GR |
630 | } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
631 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); | |
632 | goto discard; | |
7c657876 ACM |
633 | } |
634 | ||
8109b02b | 635 | if (!queued) { |
7c657876 ACM |
636 | discard: |
637 | __kfree_skb(skb); | |
638 | } | |
639 | return 0; | |
640 | } | |
f21e68ca ACM |
641 | |
642 | EXPORT_SYMBOL_GPL(dccp_rcv_state_process); | |
4712a792 GR |
643 | |
644 | /** | |
3393da82 GR |
645 | * dccp_sample_rtt - Validate and finalise computation of RTT sample |
646 | * @delta: number of microseconds between packet and acknowledgment | |
647 | * The routine is kept generic to work in different contexts. It should be | |
648 | * called immediately when the ACK used for the RTT sample arrives. | |
4712a792 | 649 | */ |
3393da82 | 650 | u32 dccp_sample_rtt(struct sock *sk, long delta) |
4712a792 | 651 | { |
3393da82 GR |
652 | /* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
653 | delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; | |
4712a792 GR |
654 | |
655 | if (unlikely(delta <= 0)) { | |
3393da82 | 656 | DCCP_WARN("unusable RTT sample %ld, using min\n", delta); |
4712a792 GR |
657 | return DCCP_SANE_RTT_MIN; |
658 | } | |
3393da82 GR |
659 | if (unlikely(delta > DCCP_SANE_RTT_MAX)) { |
660 | DCCP_WARN("RTT sample %ld too large, using max\n", delta); | |
4712a792 GR |
661 | return DCCP_SANE_RTT_MAX; |
662 | } | |
663 | ||
664 | return delta; | |
665 | } | |
666 | ||
667 | EXPORT_SYMBOL_GPL(dccp_sample_rtt); |