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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7c657876 ACM |
2 | /* |
3 | * net/dccp/input.c | |
8109b02b | 4 | * |
7c657876 ACM |
5 | * An implementation of the DCCP protocol |
6 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
7c657876 ACM |
7 | */ |
8 | ||
7c657876 ACM |
9 | #include <linux/dccp.h> |
10 | #include <linux/skbuff.h> | |
5a0e3ad6 | 11 | #include <linux/slab.h> |
7c657876 ACM |
12 | |
13 | #include <net/sock.h> | |
14 | ||
ae31c339 | 15 | #include "ackvec.h" |
7c657876 ACM |
16 | #include "ccid.h" |
17 | #include "dccp.h" | |
18 | ||
bd5435e7 IM |
19 | /* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */ |
20 | int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8; | |
21 | ||
69567d0b | 22 | static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb) |
7c657876 | 23 | { |
7c657876 ACM |
24 | __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4); |
25 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
26 | skb_set_owner_r(skb, sk); | |
676d2369 | 27 | sk->sk_data_ready(sk); |
7c657876 ACM |
28 | } |
29 | ||
69567d0b GR |
30 | static void dccp_fin(struct sock *sk, struct sk_buff *skb) |
31 | { | |
32 | /* | |
33 | * On receiving Close/CloseReq, both RD/WR shutdown are performed. | |
34 | * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after | |
35 | * receiving the closing segment, but there is no guarantee that such | |
36 | * data will be processed at all. | |
37 | */ | |
38 | sk->sk_shutdown = SHUTDOWN_MASK; | |
39 | sock_set_flag(sk, SOCK_DONE); | |
40 | dccp_enqueue_skb(sk, skb); | |
41 | } | |
42 | ||
0c869620 | 43 | static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb) |
7c657876 | 44 | { |
0c869620 GR |
45 | int queued = 0; |
46 | ||
47 | switch (sk->sk_state) { | |
48 | /* | |
49 | * We ignore Close when received in one of the following states: | |
50 | * - CLOSED (may be a late or duplicate packet) | |
51 | * - PASSIVE_CLOSEREQ (the peer has sent a CloseReq earlier) | |
52 | * - RESPOND (already handled by dccp_check_req) | |
53 | */ | |
54 | case DCCP_CLOSING: | |
55 | /* | |
56 | * Simultaneous-close: receiving a Close after sending one. This | |
57 | * can happen if both client and server perform active-close and | |
58 | * will result in an endless ping-pong of crossing and retrans- | |
59 | * mitted Close packets, which only terminates when one of the | |
60 | * nodes times out (min. 64 seconds). Quicker convergence can be | |
61 | * achieved when one of the nodes acts as tie-breaker. | |
62 | * This is ok as both ends are done with data transfer and each | |
63 | * end is just waiting for the other to acknowledge termination. | |
64 | */ | |
65 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) | |
66 | break; | |
67 | /* fall through */ | |
68 | case DCCP_REQUESTING: | |
69 | case DCCP_ACTIVE_CLOSEREQ: | |
70 | dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED); | |
71 | dccp_done(sk); | |
72 | break; | |
73 | case DCCP_OPEN: | |
74 | case DCCP_PARTOPEN: | |
75 | /* Give waiting application a chance to read pending data */ | |
76 | queued = 1; | |
77 | dccp_fin(sk, skb); | |
78 | dccp_set_state(sk, DCCP_PASSIVE_CLOSE); | |
79 | /* fall through */ | |
80 | case DCCP_PASSIVE_CLOSE: | |
81 | /* | |
82 | * Retransmitted Close: we have already enqueued the first one. | |
83 | */ | |
84 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); | |
85 | } | |
86 | return queued; | |
7c657876 ACM |
87 | } |
88 | ||
0c869620 | 89 | static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) |
7c657876 | 90 | { |
0c869620 GR |
91 | int queued = 0; |
92 | ||
7c657876 ACM |
93 | /* |
94 | * Step 7: Check for unexpected packet types | |
95 | * If (S.is_server and P.type == CloseReq) | |
96 | * Send Sync packet acknowledging P.seqno | |
97 | * Drop packet and return | |
98 | */ | |
99 | if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) { | |
e92ae93a | 100 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); |
0c869620 | 101 | return queued; |
7c657876 ACM |
102 | } |
103 | ||
0c869620 GR |
104 | /* Step 13: process relevant Client states < CLOSEREQ */ |
105 | switch (sk->sk_state) { | |
106 | case DCCP_REQUESTING: | |
107 | dccp_send_close(sk, 0); | |
811265b8 | 108 | dccp_set_state(sk, DCCP_CLOSING); |
0c869620 GR |
109 | break; |
110 | case DCCP_OPEN: | |
111 | case DCCP_PARTOPEN: | |
112 | /* Give waiting application a chance to read pending data */ | |
113 | queued = 1; | |
114 | dccp_fin(sk, skb); | |
115 | dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ); | |
116 | /* fall through */ | |
117 | case DCCP_PASSIVE_CLOSEREQ: | |
118 | sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); | |
119 | } | |
120 | return queued; | |
7c657876 ACM |
121 | } |
122 | ||
d9b52dc6 | 123 | static u16 dccp_reset_code_convert(const u8 code) |
d8ef2c29 | 124 | { |
5e349fc0 | 125 | static const u16 error_code[] = { |
d8ef2c29 GR |
126 | [DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */ |
127 | [DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */ | |
128 | [DCCP_RESET_CODE_ABORTED] = ECONNRESET, | |
129 | ||
130 | [DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED, | |
131 | [DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED, | |
132 | [DCCP_RESET_CODE_TOO_BUSY] = EUSERS, | |
133 | [DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT, | |
134 | ||
135 | [DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG, | |
136 | [DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR, | |
137 | [DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC, | |
138 | [DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ, | |
139 | [DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP, | |
140 | }; | |
141 | ||
142 | return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code]; | |
143 | } | |
144 | ||
145 | static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb) | |
146 | { | |
d9b52dc6 | 147 | u16 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code); |
d8ef2c29 GR |
148 | |
149 | sk->sk_err = err; | |
150 | ||
151 | /* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */ | |
152 | dccp_fin(sk, skb); | |
153 | ||
154 | if (err && !sock_flag(sk, SOCK_DEAD)) | |
8d8ad9d7 | 155 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR); |
d8ef2c29 GR |
156 | dccp_time_wait(sk, DCCP_TIME_WAIT, 0); |
157 | } | |
158 | ||
18219463 | 159 | static void dccp_handle_ackvec_processing(struct sock *sk, struct sk_buff *skb) |
7c657876 | 160 | { |
18219463 | 161 | struct dccp_ackvec *av = dccp_sk(sk)->dccps_hc_rx_ackvec; |
7c657876 | 162 | |
18219463 GR |
163 | if (av == NULL) |
164 | return; | |
165 | if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
166 | dccp_ackvec_clear_state(av, DCCP_SKB_CB(skb)->dccpd_ack_seq); | |
167 | dccp_ackvec_input(av, skb); | |
7c657876 ACM |
168 | } |
169 | ||
8e8c71f1 GR |
170 | static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb) |
171 | { | |
172 | const struct dccp_sock *dp = dccp_sk(sk); | |
173 | ||
174 | /* Don't deliver to RX CCID when node has shut down read end. */ | |
175 | if (!(sk->sk_shutdown & RCV_SHUTDOWN)) | |
176 | ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb); | |
177 | /* | |
178 | * Until the TX queue has been drained, we can not honour SHUT_WR, since | |
179 | * we need received feedback as input to adjust congestion control. | |
180 | */ | |
181 | if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN)) | |
182 | ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb); | |
183 | } | |
184 | ||
7c657876 ACM |
185 | static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) |
186 | { | |
187 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
188 | struct dccp_sock *dp = dccp_sk(sk); | |
cbe1f5f8 GR |
189 | u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, |
190 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
7c657876 ACM |
191 | |
192 | /* | |
193 | * Step 5: Prepare sequence numbers for Sync | |
194 | * If P.type == Sync or P.type == SyncAck, | |
195 | * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL, | |
196 | * / * P is valid, so update sequence number variables | |
197 | * accordingly. After this update, P will pass the tests | |
198 | * in Step 6. A SyncAck is generated if necessary in | |
199 | * Step 15 * / | |
200 | * Update S.GSR, S.SWL, S.SWH | |
201 | * Otherwise, | |
202 | * Drop packet and return | |
203 | */ | |
8109b02b | 204 | if (dh->dccph_type == DCCP_PKT_SYNC || |
7c657876 | 205 | dh->dccph_type == DCCP_PKT_SYNCACK) { |
cbe1f5f8 GR |
206 | if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && |
207 | dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) | |
208 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
209 | else |
210 | return -1; | |
e92ae93a | 211 | } |
c9eaf173 | 212 | |
7c657876 ACM |
213 | /* |
214 | * Step 6: Check sequence numbers | |
215 | * Let LSWL = S.SWL and LAWL = S.AWL | |
216 | * If P.type == CloseReq or P.type == Close or P.type == Reset, | |
217 | * LSWL := S.GSR + 1, LAWL := S.GAR | |
218 | * If LSWL <= P.seqno <= S.SWH | |
219 | * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH), | |
220 | * Update S.GSR, S.SWL, S.SWH | |
221 | * If P.type != Sync, | |
222 | * Update S.GAR | |
7c657876 | 223 | */ |
e92ae93a ACM |
224 | lswl = dp->dccps_swl; |
225 | lawl = dp->dccps_awl; | |
226 | ||
227 | if (dh->dccph_type == DCCP_PKT_CLOSEREQ || | |
c59eab46 ACM |
228 | dh->dccph_type == DCCP_PKT_CLOSE || |
229 | dh->dccph_type == DCCP_PKT_RESET) { | |
cbe1f5f8 | 230 | lswl = ADD48(dp->dccps_gsr, 1); |
7c657876 ACM |
231 | lawl = dp->dccps_gar; |
232 | } | |
233 | ||
cbe1f5f8 GR |
234 | if (between48(seqno, lswl, dp->dccps_swh) && |
235 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || | |
236 | between48(ackno, lawl, dp->dccps_awh))) { | |
237 | dccp_update_gsr(sk, seqno); | |
7c657876 ACM |
238 | |
239 | if (dh->dccph_type != DCCP_PKT_SYNC && | |
0ac78870 GR |
240 | ackno != DCCP_PKT_WITHOUT_ACK_SEQ && |
241 | after48(ackno, dp->dccps_gar)) | |
cbe1f5f8 | 242 | dp->dccps_gar = ackno; |
7c657876 | 243 | } else { |
a94f0f97 GR |
244 | unsigned long now = jiffies; |
245 | /* | |
246 | * Step 6: Check sequence numbers | |
247 | * Otherwise, | |
248 | * If P.type == Reset, | |
249 | * Send Sync packet acknowledging S.GSR | |
250 | * Otherwise, | |
251 | * Send Sync packet acknowledging P.seqno | |
252 | * Drop packet and return | |
253 | * | |
254 | * These Syncs are rate-limited as per RFC 4340, 7.5.4: | |
255 | * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. | |
256 | */ | |
257 | if (time_before(now, (dp->dccps_rate_last + | |
258 | sysctl_dccp_sync_ratelimit))) | |
2cf5be93 | 259 | return -1; |
a94f0f97 | 260 | |
2f34b329 | 261 | DCCP_WARN("Step 6 failed for %s packet, " |
59348b19 GR |
262 | "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " |
263 | "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " | |
264 | "sending SYNC...\n", dccp_packet_name(dh->dccph_type), | |
cbe1f5f8 | 265 | (unsigned long long) lswl, (unsigned long long) seqno, |
59348b19 | 266 | (unsigned long long) dp->dccps_swh, |
cbe1f5f8 GR |
267 | (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" |
268 | : "exists", | |
269 | (unsigned long long) lawl, (unsigned long long) ackno, | |
59348b19 | 270 | (unsigned long long) dp->dccps_awh); |
a94f0f97 GR |
271 | |
272 | dp->dccps_rate_last = now; | |
273 | ||
e155d769 GR |
274 | if (dh->dccph_type == DCCP_PKT_RESET) |
275 | seqno = dp->dccps_gsr; | |
cbe1f5f8 | 276 | dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |
7c657876 ACM |
277 | return -1; |
278 | } | |
279 | ||
280 | return 0; | |
281 | } | |
282 | ||
c25a18ba | 283 | static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
95c96174 | 284 | const struct dccp_hdr *dh, const unsigned int len) |
7c657876 ACM |
285 | { |
286 | struct dccp_sock *dp = dccp_sk(sk); | |
287 | ||
7c657876 ACM |
288 | switch (dccp_hdr(skb)->dccph_type) { |
289 | case DCCP_PKT_DATAACK: | |
290 | case DCCP_PKT_DATA: | |
291 | /* | |
8e8c71f1 GR |
292 | * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when |
293 | * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening" | |
294 | * - sk_receive_queue is full, use Code 2, "Receive Buffer" | |
7c657876 | 295 | */ |
69567d0b | 296 | dccp_enqueue_skb(sk, skb); |
7c657876 ACM |
297 | return 0; |
298 | case DCCP_PKT_ACK: | |
299 | goto discard; | |
300 | case DCCP_PKT_RESET: | |
301 | /* | |
302 | * Step 9: Process Reset | |
303 | * If P.type == Reset, | |
304 | * Tear down connection | |
305 | * S.state := TIMEWAIT | |
306 | * Set TIMEWAIT timer | |
307 | * Drop packet and return | |
d8ef2c29 GR |
308 | */ |
309 | dccp_rcv_reset(sk, skb); | |
7c657876 ACM |
310 | return 0; |
311 | case DCCP_PKT_CLOSEREQ: | |
0c869620 GR |
312 | if (dccp_rcv_closereq(sk, skb)) |
313 | return 0; | |
7c657876 ACM |
314 | goto discard; |
315 | case DCCP_PKT_CLOSE: | |
0c869620 GR |
316 | if (dccp_rcv_close(sk, skb)) |
317 | return 0; | |
318 | goto discard; | |
7c657876 | 319 | case DCCP_PKT_REQUEST: |
8109b02b ACM |
320 | /* Step 7 |
321 | * or (S.is_server and P.type == Response) | |
7c657876 ACM |
322 | * or (S.is_client and P.type == Request) |
323 | * or (S.state >= OPEN and P.type == Request | |
324 | * and P.seqno >= S.OSR) | |
325 | * or (S.state >= OPEN and P.type == Response | |
326 | * and P.seqno >= S.OSR) | |
327 | * or (S.state == RESPOND and P.type == Data), | |
328 | * Send Sync packet acknowledging P.seqno | |
329 | * Drop packet and return | |
330 | */ | |
331 | if (dp->dccps_role != DCCP_ROLE_LISTEN) | |
332 | goto send_sync; | |
333 | goto check_seq; | |
334 | case DCCP_PKT_RESPONSE: | |
335 | if (dp->dccps_role != DCCP_ROLE_CLIENT) | |
336 | goto send_sync; | |
337 | check_seq: | |
8d13bf9a GR |
338 | if (dccp_delta_seqno(dp->dccps_osr, |
339 | DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { | |
7c657876 | 340 | send_sync: |
e92ae93a ACM |
341 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, |
342 | DCCP_PKT_SYNC); | |
7c657876 ACM |
343 | } |
344 | break; | |
e92ae93a ACM |
345 | case DCCP_PKT_SYNC: |
346 | dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, | |
347 | DCCP_PKT_SYNCACK); | |
348 | /* | |
0e64e94e | 349 | * From RFC 4340, sec. 5.7 |
e92ae93a ACM |
350 | * |
351 | * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets | |
352 | * MAY have non-zero-length application data areas, whose | |
0e64e94e | 353 | * contents receivers MUST ignore. |
e92ae93a ACM |
354 | */ |
355 | goto discard; | |
7c657876 ACM |
356 | } |
357 | ||
7309f882 | 358 | DCCP_INC_STATS(DCCP_MIB_INERRS); |
7c657876 ACM |
359 | discard: |
360 | __kfree_skb(skb); | |
361 | return 0; | |
362 | } | |
363 | ||
709dd3aa | 364 | int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, |
95c96174 | 365 | const struct dccp_hdr *dh, const unsigned int len) |
709dd3aa | 366 | { |
709dd3aa AB |
367 | if (dccp_check_seqno(sk, skb)) |
368 | goto discard; | |
369 | ||
8b819412 | 370 | if (dccp_parse_options(sk, NULL, skb)) |
ba1a6c7b | 371 | return 1; |
709dd3aa | 372 | |
18219463 | 373 | dccp_handle_ackvec_processing(sk, skb); |
8e8c71f1 | 374 | dccp_deliver_input_to_ccids(sk, skb); |
709dd3aa AB |
375 | |
376 | return __dccp_rcv_established(sk, skb, dh, len); | |
377 | discard: | |
378 | __kfree_skb(skb); | |
379 | return 0; | |
380 | } | |
381 | ||
f21e68ca ACM |
382 | EXPORT_SYMBOL_GPL(dccp_rcv_established); |
383 | ||
7c657876 ACM |
384 | static int dccp_rcv_request_sent_state_process(struct sock *sk, |
385 | struct sk_buff *skb, | |
386 | const struct dccp_hdr *dh, | |
95c96174 | 387 | const unsigned int len) |
7c657876 | 388 | { |
8109b02b | 389 | /* |
7c657876 ACM |
390 | * Step 4: Prepare sequence numbers in REQUEST |
391 | * If S.state == REQUEST, | |
392 | * If (P.type == Response or P.type == Reset) | |
393 | * and S.AWL <= P.ackno <= S.AWH, | |
394 | * / * Set sequence number variables corresponding to the | |
395 | * other endpoint, so P will pass the tests in Step 6 * / | |
396 | * Set S.GSR, S.ISR, S.SWL, S.SWH | |
397 | * / * Response processing continues in Step 10; Reset | |
398 | * processing continues in Step 9 * / | |
399 | */ | |
400 | if (dh->dccph_type == DCCP_PKT_RESPONSE) { | |
401 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
402 | struct dccp_sock *dp = dccp_sk(sk); | |
3393da82 | 403 | long tstamp = dccp_timestamp(); |
7c657876 | 404 | |
7690af3f ACM |
405 | if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, |
406 | dp->dccps_awl, dp->dccps_awh)) { | |
407 | dccp_pr_debug("invalid ackno: S.AWL=%llu, " | |
b1383380 | 408 | "P.ackno=%llu, S.AWH=%llu\n", |
7690af3f ACM |
409 | (unsigned long long)dp->dccps_awl, |
410 | (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, | |
411 | (unsigned long long)dp->dccps_awh); | |
7c657876 ACM |
412 | goto out_invalid_packet; |
413 | } | |
9e377202 | 414 | |
991d927c GR |
415 | /* |
416 | * If option processing (Step 8) failed, return 1 here so that | |
417 | * dccp_v4_do_rcv() sends a Reset. The Reset code depends on | |
418 | * the option type and is set in dccp_parse_options(). | |
419 | */ | |
8b819412 | 420 | if (dccp_parse_options(sk, NULL, skb)) |
991d927c | 421 | return 1; |
afe00251 | 422 | |
59b80802 | 423 | /* Obtain usec RTT sample from SYN exchange (used by TFRC). */ |
3393da82 GR |
424 | if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) |
425 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - | |
426 | dp->dccps_options_received.dccpor_timestamp_echo)); | |
89560b53 | 427 | |
d28934ad GR |
428 | /* Stop the REQUEST timer */ |
429 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
430 | WARN_ON(sk->sk_send_head == NULL); | |
431 | kfree_skb(sk->sk_send_head); | |
432 | sk->sk_send_head = NULL; | |
433 | ||
03ace394 | 434 | /* |
0b53d460 GR |
435 | * Set ISR, GSR from packet. ISS was set in dccp_v{4,6}_connect |
436 | * and GSS in dccp_transmit_skb(). Setting AWL/AWH and SWL/SWH | |
437 | * is done as part of activating the feature values below, since | |
438 | * these settings depend on the local/remote Sequence Window | |
439 | * features, which were undefined or not confirmed until now. | |
03ace394 | 440 | */ |
0b53d460 | 441 | dp->dccps_gsr = dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; |
7c657876 | 442 | |
d83d8461 | 443 | dccp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
7c657876 ACM |
444 | |
445 | /* | |
446 | * Step 10: Process REQUEST state (second part) | |
447 | * If S.state == REQUEST, | |
7690af3f ACM |
448 | * / * If we get here, P is a valid Response from the |
449 | * server (see Step 4), and we should move to | |
450 | * PARTOPEN state. PARTOPEN means send an Ack, | |
451 | * don't send Data packets, retransmit Acks | |
452 | * periodically, and always include any Init Cookie | |
453 | * from the Response * / | |
7c657876 ACM |
454 | * S.state := PARTOPEN |
455 | * Set PARTOPEN timer | |
8109b02b | 456 | * Continue with S.state == PARTOPEN |
7690af3f ACM |
457 | * / * Step 12 will send the Ack completing the |
458 | * three-way handshake * / | |
7c657876 ACM |
459 | */ |
460 | dccp_set_state(sk, DCCP_PARTOPEN); | |
461 | ||
991d927c GR |
462 | /* |
463 | * If feature negotiation was successful, activate features now; | |
464 | * an activation failure means that this host could not activate | |
465 | * one ore more features (e.g. insufficient memory), which would | |
466 | * leave at least one feature in an undefined state. | |
467 | */ | |
468 | if (dccp_feat_activate_values(sk, &dp->dccps_featneg)) | |
469 | goto unable_to_proceed; | |
470 | ||
7c657876 | 471 | /* Make sure socket is routed, for correct metrics. */ |
57cca05a | 472 | icsk->icsk_af_ops->rebuild_header(sk); |
7c657876 ACM |
473 | |
474 | if (!sock_flag(sk, SOCK_DEAD)) { | |
475 | sk->sk_state_change(sk); | |
8d8ad9d7 | 476 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
7c657876 ACM |
477 | } |
478 | ||
31954cd8 | 479 | if (sk->sk_write_pending || inet_csk_in_pingpong_mode(sk) || |
7c657876 ACM |
480 | icsk->icsk_accept_queue.rskq_defer_accept) { |
481 | /* Save one ACK. Data will be ready after | |
482 | * several ticks, if write_pending is set. | |
483 | * | |
484 | * It may be deleted, but with this feature tcpdumps | |
485 | * look so _wonderfully_ clever, that I was not able | |
486 | * to stand against the temptation 8) --ANK | |
487 | */ | |
488 | /* | |
489 | * OK, in DCCP we can as well do a similar trick, its | |
490 | * even in the draft, but there is no need for us to | |
491 | * schedule an ack here, as dccp_sendmsg does this for | |
492 | * us, also stated in the draft. -acme | |
493 | */ | |
494 | __kfree_skb(skb); | |
495 | return 0; | |
8109b02b | 496 | } |
7c657876 ACM |
497 | dccp_send_ack(sk); |
498 | return -1; | |
499 | } | |
500 | ||
501 | out_invalid_packet: | |
0c10c5d9 ACM |
502 | /* dccp_v4_do_rcv will send a reset */ |
503 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; | |
8109b02b | 504 | return 1; |
991d927c GR |
505 | |
506 | unable_to_proceed: | |
507 | DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED; | |
508 | /* | |
509 | * We mark this socket as no longer usable, so that the loop in | |
510 | * dccp_sendmsg() terminates and the application gets notified. | |
511 | */ | |
512 | dccp_set_state(sk, DCCP_CLOSED); | |
513 | sk->sk_err = ECOMM; | |
514 | return 1; | |
7c657876 ACM |
515 | } |
516 | ||
517 | static int dccp_rcv_respond_partopen_state_process(struct sock *sk, | |
518 | struct sk_buff *skb, | |
519 | const struct dccp_hdr *dh, | |
95c96174 | 520 | const unsigned int len) |
7c657876 | 521 | { |
59b80802 GR |
522 | struct dccp_sock *dp = dccp_sk(sk); |
523 | u32 sample = dp->dccps_options_received.dccpor_timestamp_echo; | |
7c657876 ACM |
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; | |
bc28df6e | 533 | /* fall through */ |
7c657876 ACM |
534 | case DCCP_PKT_DATAACK: |
535 | case DCCP_PKT_ACK: | |
536 | /* | |
a77b6343 | 537 | * FIXME: we should be resetting the PARTOPEN (DELACK) timer |
7690af3f ACM |
538 | * here but only if we haven't used the DELACK timer for |
539 | * something else, like sending a delayed ack for a TIMESTAMP | |
540 | * echo, etc, for now were not clearing it, sending an extra | |
541 | * ACK when there is nothing else to do in DELACK is not a big | |
542 | * deal after all. | |
7c657876 ACM |
543 | */ |
544 | ||
545 | /* Stop the PARTOPEN timer */ | |
546 | if (sk->sk_state == DCCP_PARTOPEN) | |
547 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
548 | ||
59b80802 GR |
549 | /* Obtain usec RTT sample from SYN exchange (used by TFRC). */ |
550 | if (likely(sample)) { | |
551 | long delta = dccp_timestamp() - sample; | |
552 | ||
553 | dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * delta); | |
554 | } | |
555 | ||
556 | dp->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq; | |
7c657876 ACM |
557 | dccp_set_state(sk, DCCP_OPEN); |
558 | ||
2a9bc9bb ACM |
559 | if (dh->dccph_type == DCCP_PKT_DATAACK || |
560 | dh->dccph_type == DCCP_PKT_DATA) { | |
709dd3aa | 561 | __dccp_rcv_established(sk, skb, dh, len); |
7690af3f | 562 | queued = 1; /* packet was queued |
709dd3aa | 563 | (by __dccp_rcv_established) */ |
7c657876 ACM |
564 | } |
565 | break; | |
566 | } | |
567 | ||
568 | return queued; | |
569 | } | |
570 | ||
571 | int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
95c96174 | 572 | struct dccp_hdr *dh, unsigned int len) |
7c657876 ACM |
573 | { |
574 | struct dccp_sock *dp = dccp_sk(sk); | |
0c10c5d9 | 575 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
7c657876 | 576 | const int old_state = sk->sk_state; |
449809a6 | 577 | bool acceptable; |
7c657876 ACM |
578 | int queued = 0; |
579 | ||
8649b0d4 ACM |
580 | /* |
581 | * Step 3: Process LISTEN state | |
8649b0d4 ACM |
582 | * |
583 | * If S.state == LISTEN, | |
d83ca5ac GR |
584 | * If P.type == Request or P contains a valid Init Cookie option, |
585 | * (* Must scan the packet's options to check for Init | |
586 | * Cookies. Only Init Cookies are processed here, | |
587 | * however; other options are processed in Step 8. This | |
588 | * scan need only be performed if the endpoint uses Init | |
589 | * Cookies *) | |
590 | * (* Generate a new socket and switch to that socket *) | |
591 | * Set S := new socket for this port pair | |
592 | * S.state = RESPOND | |
593 | * Choose S.ISS (initial seqno) or set from Init Cookies | |
594 | * Initialize S.GAR := S.ISS | |
595 | * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init | |
596 | * Cookies Continue with S.state == RESPOND | |
597 | * (* A Response packet will be generated in Step 11 *) | |
598 | * Otherwise, | |
599 | * Generate Reset(No Connection) unless P.type == Reset | |
600 | * Drop packet and return | |
8649b0d4 ACM |
601 | */ |
602 | if (sk->sk_state == DCCP_LISTEN) { | |
603 | if (dh->dccph_type == DCCP_PKT_REQUEST) { | |
449809a6 | 604 | /* It is possible that we process SYN packets from backlog, |
1ad98e9d | 605 | * so we need to make sure to disable BH and RCU right there. |
449809a6 | 606 | */ |
1ad98e9d | 607 | rcu_read_lock(); |
449809a6 ED |
608 | local_bh_disable(); |
609 | acceptable = inet_csk(sk)->icsk_af_ops->conn_request(sk, skb) >= 0; | |
610 | local_bh_enable(); | |
1ad98e9d | 611 | rcu_read_unlock(); |
449809a6 | 612 | if (!acceptable) |
8649b0d4 | 613 | return 1; |
5edabca9 AK |
614 | consume_skb(skb); |
615 | return 0; | |
8649b0d4 ACM |
616 | } |
617 | if (dh->dccph_type == DCCP_PKT_RESET) | |
618 | goto discard; | |
619 | ||
0c10c5d9 ACM |
620 | /* Caller (dccp_v4_do_rcv) will send Reset */ |
621 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
8649b0d4 | 622 | return 1; |
720dc34b GR |
623 | } else if (sk->sk_state == DCCP_CLOSED) { |
624 | dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; | |
625 | return 1; | |
8649b0d4 ACM |
626 | } |
627 | ||
c0c20150 GR |
628 | /* Step 6: Check sequence numbers (omitted in LISTEN/REQUEST state) */ |
629 | if (sk->sk_state != DCCP_REQUESTING && dccp_check_seqno(sk, skb)) | |
630 | goto discard; | |
7c657876 | 631 | |
c0c20150 GR |
632 | /* |
633 | * Step 7: Check for unexpected packet types | |
634 | * If (S.is_server and P.type == Response) | |
635 | * or (S.is_client and P.type == Request) | |
636 | * or (S.state == RESPOND and P.type == Data), | |
637 | * Send Sync packet acknowledging P.seqno | |
638 | * Drop packet and return | |
639 | */ | |
640 | if ((dp->dccps_role != DCCP_ROLE_CLIENT && | |
641 | dh->dccph_type == DCCP_PKT_RESPONSE) || | |
642 | (dp->dccps_role == DCCP_ROLE_CLIENT && | |
643 | dh->dccph_type == DCCP_PKT_REQUEST) || | |
644 | (sk->sk_state == DCCP_RESPOND && dh->dccph_type == DCCP_PKT_DATA)) { | |
645 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC); | |
646 | goto discard; | |
410e27a4 | 647 | } |
ddab0556 | 648 | |
c0c20150 GR |
649 | /* Step 8: Process options */ |
650 | if (dccp_parse_options(sk, NULL, skb)) | |
651 | return 1; | |
652 | ||
7c657876 ACM |
653 | /* |
654 | * Step 9: Process Reset | |
655 | * If P.type == Reset, | |
656 | * Tear down connection | |
657 | * S.state := TIMEWAIT | |
658 | * Set TIMEWAIT timer | |
659 | * Drop packet and return | |
c0c20150 | 660 | */ |
7c657876 | 661 | if (dh->dccph_type == DCCP_PKT_RESET) { |
d8ef2c29 | 662 | dccp_rcv_reset(sk, skb); |
7c657876 | 663 | return 0; |
c0c20150 | 664 | } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) { /* Step 13 */ |
0c869620 GR |
665 | if (dccp_rcv_closereq(sk, skb)) |
666 | return 0; | |
7ad07e7c | 667 | goto discard; |
c0c20150 | 668 | } else if (dh->dccph_type == DCCP_PKT_CLOSE) { /* Step 14 */ |
0c869620 GR |
669 | if (dccp_rcv_close(sk, skb)) |
670 | return 0; | |
671 | goto discard; | |
7c657876 ACM |
672 | } |
673 | ||
674 | switch (sk->sk_state) { | |
7c657876 | 675 | case DCCP_REQUESTING: |
7c657876 ACM |
676 | queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len); |
677 | if (queued >= 0) | |
678 | return queued; | |
679 | ||
680 | __kfree_skb(skb); | |
681 | return 0; | |
682 | ||
410e27a4 | 683 | case DCCP_PARTOPEN: |
c0c20150 GR |
684 | /* Step 8: if using Ack Vectors, mark packet acknowledgeable */ |
685 | dccp_handle_ackvec_processing(sk, skb); | |
686 | dccp_deliver_input_to_ccids(sk, skb); | |
687 | /* fall through */ | |
688 | case DCCP_RESPOND: | |
7690af3f ACM |
689 | queued = dccp_rcv_respond_partopen_state_process(sk, skb, |
690 | dh, len); | |
7c657876 ACM |
691 | break; |
692 | } | |
693 | ||
7690af3f ACM |
694 | if (dh->dccph_type == DCCP_PKT_ACK || |
695 | dh->dccph_type == DCCP_PKT_DATAACK) { | |
7c657876 ACM |
696 | switch (old_state) { |
697 | case DCCP_PARTOPEN: | |
698 | sk->sk_state_change(sk); | |
8d8ad9d7 | 699 | sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); |
7c657876 ACM |
700 | break; |
701 | } | |
08831700 GR |
702 | } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { |
703 | dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); | |
704 | goto discard; | |
7c657876 ACM |
705 | } |
706 | ||
8109b02b | 707 | if (!queued) { |
7c657876 ACM |
708 | discard: |
709 | __kfree_skb(skb); | |
710 | } | |
711 | return 0; | |
712 | } | |
f21e68ca ACM |
713 | |
714 | EXPORT_SYMBOL_GPL(dccp_rcv_state_process); | |
4712a792 GR |
715 | |
716 | /** | |
3393da82 GR |
717 | * dccp_sample_rtt - Validate and finalise computation of RTT sample |
718 | * @delta: number of microseconds between packet and acknowledgment | |
2c53040f | 719 | * |
3393da82 GR |
720 | * The routine is kept generic to work in different contexts. It should be |
721 | * called immediately when the ACK used for the RTT sample arrives. | |
4712a792 | 722 | */ |
3393da82 | 723 | u32 dccp_sample_rtt(struct sock *sk, long delta) |
4712a792 | 724 | { |
3393da82 GR |
725 | /* dccpor_elapsed_time is either zeroed out or set and > 0 */ |
726 | delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; | |
4712a792 | 727 | |
410e27a4 GR |
728 | if (unlikely(delta <= 0)) { |
729 | DCCP_WARN("unusable RTT sample %ld, using min\n", delta); | |
730 | return DCCP_SANE_RTT_MIN; | |
731 | } | |
732 | if (unlikely(delta > DCCP_SANE_RTT_MAX)) { | |
733 | DCCP_WARN("RTT sample %ld too large, using max\n", delta); | |
734 | return DCCP_SANE_RTT_MAX; | |
735 | } | |
736 | ||
737 | return delta; | |
4712a792 | 738 | } |