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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/input.c
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -02003 *
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07004 * 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
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070013#include <linux/dccp.h>
14#include <linux/skbuff.h>
15
16#include <net/sock.h>
17
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070018#include "ackvec.h"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070019#include "ccid.h"
20#include "dccp.h"
21
Ingo Molnarbd5435e2007-10-17 19:33:06 -070022/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
23int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8;
24
Gerrit Renker69567d02007-12-13 11:28:43 -020025static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070026{
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070027 __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
Gerrit Renker69567d02007-12-13 11:28:43 -020033static 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
Gerrit Renker0c869622007-11-28 11:59:48 -020046static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070047{
Gerrit Renker0c869622007-11-28 11:59:48 -020048 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;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070090}
91
Gerrit Renker0c869622007-11-28 11:59:48 -020092static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070093{
Gerrit Renker0c869622007-11-28 11:59:48 -020094 int queued = 0;
95
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070096 /*
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) {
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300103 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
Gerrit Renker0c869622007-11-28 11:59:48 -0200104 return queued;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700105 }
106
Gerrit Renker0c869622007-11-28 11:59:48 -0200107 /* Step 13: process relevant Client states < CLOSEREQ */
108 switch (sk->sk_state) {
109 case DCCP_REQUESTING:
110 dccp_send_close(sk, 0);
Arnaldo Carvalho de Melo811265b2005-09-13 19:03:15 -0300111 dccp_set_state(sk, DCCP_CLOSING);
Gerrit Renker0c869622007-11-28 11:59:48 -0200112 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;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700124}
125
Gerrit Renkerd8ef2c22007-10-24 10:27:48 -0200126static 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
148static 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))
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +0800158 sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
Gerrit Renkerd8ef2c22007-10-24 10:27:48 -0200159 dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
160}
161
Gerrit Renker410e27a2008-09-09 13:27:22 +0200162static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700163{
Gerrit Renker410e27a2008-09-09 13:27:22 +0200164 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700165
Gerrit Renker410e27a2008-09-09 13:27:22 +0200166 if (dccp_msk(sk)->dccpms_send_ack_vector)
167 dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
168 DCCP_SKB_CB(skb)->dccpd_ack_seq);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700169}
170
Gerrit Renker8e8c71f2007-11-21 09:56:48 -0200171static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)
172{
173 const struct dccp_sock *dp = dccp_sk(sk);
174
175 /* Don't deliver to RX CCID when node has shut down read end. */
176 if (!(sk->sk_shutdown & RCV_SHUTDOWN))
177 ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
178 /*
179 * Until the TX queue has been drained, we can not honour SHUT_WR, since
180 * we need received feedback as input to adjust congestion control.
181 */
182 if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN))
183 ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
184}
185
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700186static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
187{
188 const struct dccp_hdr *dh = dccp_hdr(skb);
189 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700190 u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
191 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700192
193 /*
194 * Step 5: Prepare sequence numbers for Sync
195 * If P.type == Sync or P.type == SyncAck,
196 * If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
197 * / * P is valid, so update sequence number variables
198 * accordingly. After this update, P will pass the tests
199 * in Step 6. A SyncAck is generated if necessary in
200 * Step 15 * /
201 * Update S.GSR, S.SWL, S.SWH
202 * Otherwise,
203 * Drop packet and return
204 */
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200205 if (dh->dccph_type == DCCP_PKT_SYNC ||
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700206 dh->dccph_type == DCCP_PKT_SYNCACK) {
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700207 if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
208 dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
209 dccp_update_gsr(sk, seqno);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700210 else
211 return -1;
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300212 }
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900213
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700214 /*
215 * Step 6: Check sequence numbers
216 * Let LSWL = S.SWL and LAWL = S.AWL
217 * If P.type == CloseReq or P.type == Close or P.type == Reset,
218 * LSWL := S.GSR + 1, LAWL := S.GAR
219 * If LSWL <= P.seqno <= S.SWH
220 * and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
221 * Update S.GSR, S.SWL, S.SWH
222 * If P.type != Sync,
223 * Update S.GAR
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700224 */
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300225 lswl = dp->dccps_swl;
226 lawl = dp->dccps_awl;
227
228 if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
Arnaldo Carvalho de Meloc59eab42005-08-18 21:12:02 -0300229 dh->dccph_type == DCCP_PKT_CLOSE ||
230 dh->dccph_type == DCCP_PKT_RESET) {
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700231 lswl = ADD48(dp->dccps_gsr, 1);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700232 lawl = dp->dccps_gar;
233 }
234
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700235 if (between48(seqno, lswl, dp->dccps_swh) &&
236 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
237 between48(ackno, lawl, dp->dccps_awh))) {
238 dccp_update_gsr(sk, seqno);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700239
240 if (dh->dccph_type != DCCP_PKT_SYNC &&
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700241 (ackno != DCCP_PKT_WITHOUT_ACK_SEQ))
242 dp->dccps_gar = ackno;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700243 } else {
Gerrit Renkera94f0f92007-09-26 11:31:49 -0300244 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)))
259 return 0;
260
Gerrit Renker59348b12006-11-20 18:39:23 -0200261 DCCP_WARN("DCCP: Step 6 failed for %s packet, "
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),
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700265 (unsigned long long) lswl, (unsigned long long) seqno,
Gerrit Renker59348b12006-11-20 18:39:23 -0200266 (unsigned long long) dp->dccps_swh,
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700267 (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
268 : "exists",
269 (unsigned long long) lawl, (unsigned long long) ackno,
Gerrit Renker59348b12006-11-20 18:39:23 -0200270 (unsigned long long) dp->dccps_awh);
Gerrit Renkera94f0f92007-09-26 11:31:49 -0300271
272 dp->dccps_rate_last = now;
273
Gerrit Renkere155d762007-09-25 22:41:56 -0700274 if (dh->dccph_type == DCCP_PKT_RESET)
275 seqno = dp->dccps_gsr;
Gerrit Renkercbe1f5f2007-09-25 22:41:19 -0700276 dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700277 return -1;
278 }
279
280 return 0;
281}
282
Arnaldo Carvalho de Meloc25a18b2006-03-20 21:58:56 -0800283static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
284 const struct dccp_hdr *dh, const unsigned len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700285{
286 struct dccp_sock *dp = dccp_sk(sk);
287
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700288 switch (dccp_hdr(skb)->dccph_type) {
289 case DCCP_PKT_DATAACK:
290 case DCCP_PKT_DATA:
291 /*
Gerrit Renker8e8c71f2007-11-21 09:56:48 -0200292 * 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"
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700295 */
Gerrit Renker69567d02007-12-13 11:28:43 -0200296 dccp_enqueue_skb(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700297 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
Gerrit Renkerd8ef2c22007-10-24 10:27:48 -0200308 */
309 dccp_rcv_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700310 return 0;
311 case DCCP_PKT_CLOSEREQ:
Gerrit Renker0c869622007-11-28 11:59:48 -0200312 if (dccp_rcv_closereq(sk, skb))
313 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700314 goto discard;
315 case DCCP_PKT_CLOSE:
Gerrit Renker0c869622007-11-28 11:59:48 -0200316 if (dccp_rcv_close(sk, skb))
317 return 0;
318 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700319 case DCCP_PKT_REQUEST:
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200320 /* Step 7
321 * or (S.is_server and P.type == Response)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700322 * 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;
337check_seq:
Gerrit Renker8d13bf92007-03-20 13:08:19 -0300338 if (dccp_delta_seqno(dp->dccps_osr,
339 DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700340send_sync:
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300341 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
342 DCCP_PKT_SYNC);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700343 }
344 break;
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300345 case DCCP_PKT_SYNC:
346 dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
347 DCCP_PKT_SYNCACK);
348 /*
Gerrit Renker0e64e942006-10-24 16:17:51 -0700349 * From RFC 4340, sec. 5.7
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300350 *
351 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
352 * MAY have non-zero-length application data areas, whose
Gerrit Renker0e64e942006-10-24 16:17:51 -0700353 * contents receivers MUST ignore.
Arnaldo Carvalho de Meloe92ae932005-08-17 03:10:59 -0300354 */
355 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700356 }
357
358 DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
359discard:
360 __kfree_skb(skb);
361 return 0;
362}
363
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800364int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
365 const struct dccp_hdr *dh, const unsigned len)
366{
Gerrit Renker410e27a2008-09-09 13:27:22 +0200367 struct dccp_sock *dp = dccp_sk(sk);
368
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800369 if (dccp_check_seqno(sk, skb))
370 goto discard;
371
Gerrit Renker8b819412007-12-13 12:29:24 -0200372 if (dccp_parse_options(sk, NULL, skb))
Wei Yongjunba1a6c72008-08-23 13:28:27 +0200373 return 1;
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800374
Gerrit Renker410e27a2008-09-09 13:27:22 +0200375 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
376 dccp_event_ack_recv(sk, skb);
377
378 if (dccp_msk(sk)->dccpms_send_ack_vector &&
379 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
380 DCCP_SKB_CB(skb)->dccpd_seq,
381 DCCP_ACKVEC_STATE_RECEIVED))
382 goto discard;
Gerrit Renker8e8c71f2007-11-21 09:56:48 -0200383 dccp_deliver_input_to_ccids(sk, skb);
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800384
385 return __dccp_rcv_established(sk, skb, dh, len);
386discard:
387 __kfree_skb(skb);
388 return 0;
389}
390
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800391EXPORT_SYMBOL_GPL(dccp_rcv_established);
392
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700393static int dccp_rcv_request_sent_state_process(struct sock *sk,
394 struct sk_buff *skb,
395 const struct dccp_hdr *dh,
396 const unsigned len)
397{
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200398 /*
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700399 * Step 4: Prepare sequence numbers in REQUEST
400 * If S.state == REQUEST,
401 * If (P.type == Response or P.type == Reset)
402 * and S.AWL <= P.ackno <= S.AWH,
403 * / * Set sequence number variables corresponding to the
404 * other endpoint, so P will pass the tests in Step 6 * /
405 * Set S.GSR, S.ISR, S.SWL, S.SWH
406 * / * Response processing continues in Step 10; Reset
407 * processing continues in Step 9 * /
408 */
409 if (dh->dccph_type == DCCP_PKT_RESPONSE) {
410 const struct inet_connection_sock *icsk = inet_csk(sk);
411 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker3393da82007-09-25 22:40:44 -0700412 long tstamp = dccp_timestamp();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700413
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300414 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
415 dp->dccps_awl, dp->dccps_awh)) {
416 dccp_pr_debug("invalid ackno: S.AWL=%llu, "
417 "P.ackno=%llu, S.AWH=%llu \n",
418 (unsigned long long)dp->dccps_awl,
419 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
420 (unsigned long long)dp->dccps_awh);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700421 goto out_invalid_packet;
422 }
423
Gerrit Renker8b819412007-12-13 12:29:24 -0200424 if (dccp_parse_options(sk, NULL, skb))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200425 goto out_invalid_packet;
Andrea Bittauafe00252006-03-20 17:43:56 -0800426
Gerrit Renker3393da82007-09-25 22:40:44 -0700427 /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
428 if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
429 dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
430 dp->dccps_options_received.dccpor_timestamp_echo));
Gerrit Renker89560b52007-03-20 15:27:17 -0300431
Gerrit Renker410e27a2008-09-09 13:27:22 +0200432 if (dccp_msk(sk)->dccpms_send_ack_vector &&
433 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
434 DCCP_SKB_CB(skb)->dccpd_seq,
435 DCCP_ACKVEC_STATE_RECEIVED))
436 goto out_invalid_packet; /* FIXME: change error code */
437
Gerrit Renkerd28934a2008-08-18 21:14:20 -0700438 /* Stop the REQUEST timer */
439 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
440 WARN_ON(sk->sk_send_head == NULL);
441 kfree_skb(sk->sk_send_head);
442 sk->sk_send_head = NULL;
443
Gerrit Renker410e27a2008-09-09 13:27:22 +0200444 dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
445 dccp_update_gsr(sk, dp->dccps_isr);
Arnaldo Carvalho de Melo03ace392005-08-21 05:36:45 -0300446 /*
Gerrit Renker410e27a2008-09-09 13:27:22 +0200447 * SWL and AWL are initially adjusted so that they are not less than
448 * the initial Sequence Numbers received and sent, respectively:
449 * SWL := max(GSR + 1 - floor(W/4), ISR),
450 * AWL := max(GSS - W' + 1, ISS).
451 * These adjustments MUST be applied only at the beginning of the
452 * connection.
453 *
454 * AWL was adjusted in dccp_v4_connect -acme
Arnaldo Carvalho de Melo03ace392005-08-21 05:36:45 -0300455 */
Gerrit Renker410e27a2008-09-09 13:27:22 +0200456 dccp_set_seqno(&dp->dccps_swl,
457 max48(dp->dccps_swl, dp->dccps_isr));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700458
Arnaldo Carvalho de Melod83d8462005-12-13 23:26:10 -0800459 dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700460
461 /*
462 * Step 10: Process REQUEST state (second part)
463 * If S.state == REQUEST,
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300464 * / * If we get here, P is a valid Response from the
465 * server (see Step 4), and we should move to
466 * PARTOPEN state. PARTOPEN means send an Ack,
467 * don't send Data packets, retransmit Acks
468 * periodically, and always include any Init Cookie
469 * from the Response * /
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700470 * S.state := PARTOPEN
471 * Set PARTOPEN timer
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200472 * Continue with S.state == PARTOPEN
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300473 * / * Step 12 will send the Ack completing the
474 * three-way handshake * /
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700475 */
476 dccp_set_state(sk, DCCP_PARTOPEN);
477
478 /* Make sure socket is routed, for correct metrics. */
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800479 icsk->icsk_af_ops->rebuild_header(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700480
481 if (!sock_flag(sk, SOCK_DEAD)) {
482 sk->sk_state_change(sk);
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +0800483 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700484 }
485
486 if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
487 icsk->icsk_accept_queue.rskq_defer_accept) {
488 /* Save one ACK. Data will be ready after
489 * several ticks, if write_pending is set.
490 *
491 * It may be deleted, but with this feature tcpdumps
492 * look so _wonderfully_ clever, that I was not able
493 * to stand against the temptation 8) --ANK
494 */
495 /*
496 * OK, in DCCP we can as well do a similar trick, its
497 * even in the draft, but there is no need for us to
498 * schedule an ack here, as dccp_sendmsg does this for
499 * us, also stated in the draft. -acme
500 */
501 __kfree_skb(skb);
502 return 0;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200503 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700504 dccp_send_ack(sk);
505 return -1;
506 }
507
508out_invalid_packet:
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700509 /* dccp_v4_do_rcv will send a reset */
510 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200511 return 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700512}
513
514static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
515 struct sk_buff *skb,
516 const struct dccp_hdr *dh,
517 const unsigned len)
518{
519 int queued = 0;
520
521 switch (dh->dccph_type) {
522 case DCCP_PKT_RESET:
523 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
524 break;
Arnaldo Carvalho de Melo2a9bc9b2005-10-10 21:25:00 -0700525 case DCCP_PKT_DATA:
526 if (sk->sk_state == DCCP_RESPOND)
527 break;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700528 case DCCP_PKT_DATAACK:
529 case DCCP_PKT_ACK:
530 /*
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300531 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
532 * here but only if we haven't used the DELACK timer for
533 * something else, like sending a delayed ack for a TIMESTAMP
534 * echo, etc, for now were not clearing it, sending an extra
535 * ACK when there is nothing else to do in DELACK is not a big
536 * deal after all.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700537 */
538
539 /* Stop the PARTOPEN timer */
540 if (sk->sk_state == DCCP_PARTOPEN)
541 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
542
543 dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
544 dccp_set_state(sk, DCCP_OPEN);
545
Arnaldo Carvalho de Melo2a9bc9b2005-10-10 21:25:00 -0700546 if (dh->dccph_type == DCCP_PKT_DATAACK ||
547 dh->dccph_type == DCCP_PKT_DATA) {
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800548 __dccp_rcv_established(sk, skb, dh, len);
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300549 queued = 1; /* packet was queued
Andrea Bittau709dd3a2006-01-03 14:25:17 -0800550 (by __dccp_rcv_established) */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700551 }
552 break;
553 }
554
555 return queued;
556}
557
558int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
559 struct dccp_hdr *dh, unsigned len)
560{
561 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700562 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700563 const int old_state = sk->sk_state;
564 int queued = 0;
565
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300566 /*
567 * Step 3: Process LISTEN state
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300568 *
569 * If S.state == LISTEN,
Gerrit Renkerd83ca5a2006-11-10 16:29:14 -0200570 * If P.type == Request or P contains a valid Init Cookie option,
571 * (* Must scan the packet's options to check for Init
572 * Cookies. Only Init Cookies are processed here,
573 * however; other options are processed in Step 8. This
574 * scan need only be performed if the endpoint uses Init
575 * Cookies *)
576 * (* Generate a new socket and switch to that socket *)
577 * Set S := new socket for this port pair
578 * S.state = RESPOND
579 * Choose S.ISS (initial seqno) or set from Init Cookies
580 * Initialize S.GAR := S.ISS
581 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
582 * Cookies Continue with S.state == RESPOND
583 * (* A Response packet will be generated in Step 11 *)
584 * Otherwise,
585 * Generate Reset(No Connection) unless P.type == Reset
586 * Drop packet and return
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300587 */
588 if (sk->sk_state == DCCP_LISTEN) {
589 if (dh->dccph_type == DCCP_PKT_REQUEST) {
Arnaldo Carvalho de Melo57cca052005-12-13 23:16:16 -0800590 if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
591 skb) < 0)
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300592 return 1;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200593
594 /* FIXME: do congestion control initialization */
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300595 goto discard;
596 }
597 if (dh->dccph_type == DCCP_PKT_RESET)
598 goto discard;
599
Arnaldo Carvalho de Melo0c10c5d2005-09-16 16:58:33 -0700600 /* Caller (dccp_v4_do_rcv) will send Reset */
601 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
Arnaldo Carvalho de Melo8649b0d2005-08-13 20:36:01 -0300602 return 1;
603 }
604
Gerrit Renker410e27a2008-09-09 13:27:22 +0200605 if (sk->sk_state != DCCP_REQUESTING) {
606 if (dccp_check_seqno(sk, skb))
607 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700608
Gerrit Renker410e27a2008-09-09 13:27:22 +0200609 /*
610 * Step 8: Process options and mark acknowledgeable
611 */
612 if (dccp_parse_options(sk, NULL, skb))
613 return 1;
614
615 if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
616 dccp_event_ack_recv(sk, skb);
617
618 if (dccp_msk(sk)->dccpms_send_ack_vector &&
619 dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
620 DCCP_SKB_CB(skb)->dccpd_seq,
621 DCCP_ACKVEC_STATE_RECEIVED))
622 goto discard;
623
624 dccp_deliver_input_to_ccids(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700625 }
626
627 /*
628 * Step 9: Process Reset
629 * If P.type == Reset,
630 * Tear down connection
631 * S.state := TIMEWAIT
632 * Set TIMEWAIT timer
633 * Drop packet and return
Gerrit Renker410e27a2008-09-09 13:27:22 +0200634 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700635 if (dh->dccph_type == DCCP_PKT_RESET) {
Gerrit Renkerd8ef2c22007-10-24 10:27:48 -0200636 dccp_rcv_reset(sk, skb);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700637 return 0;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200638 /*
639 * Step 7: Check for unexpected packet types
640 * If (S.is_server and P.type == Response)
641 * or (S.is_client and P.type == Request)
642 * or (S.state == RESPOND and P.type == Data),
643 * Send Sync packet acknowledging P.seqno
644 * Drop packet and return
645 */
646 } else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
647 dh->dccph_type == DCCP_PKT_RESPONSE) ||
648 (dp->dccps_role == DCCP_ROLE_CLIENT &&
649 dh->dccph_type == DCCP_PKT_REQUEST) ||
650 (sk->sk_state == DCCP_RESPOND &&
651 dh->dccph_type == DCCP_PKT_DATA)) {
652 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
653 goto discard;
654 } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
Gerrit Renker0c869622007-11-28 11:59:48 -0200655 if (dccp_rcv_closereq(sk, skb))
656 return 0;
Arnaldo Carvalho de Melo7ad07e72005-08-23 21:50:06 -0700657 goto discard;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200658 } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
Gerrit Renker0c869622007-11-28 11:59:48 -0200659 if (dccp_rcv_close(sk, skb))
660 return 0;
661 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700662 }
663
664 switch (sk->sk_state) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200665 case DCCP_CLOSED:
666 dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
667 return 1;
668
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700669 case DCCP_REQUESTING:
Gerrit Renker410e27a2008-09-09 13:27:22 +0200670 /* FIXME: do congestion control initialization */
671
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700672 queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
673 if (queued >= 0)
674 return queued;
675
676 __kfree_skb(skb);
677 return 0;
678
Gerrit Renkerddab0552008-09-04 07:30:19 +0200679 case DCCP_RESPOND:
Gerrit Renker410e27a2008-09-09 13:27:22 +0200680 case DCCP_PARTOPEN:
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300681 queued = dccp_rcv_respond_partopen_state_process(sk, skb,
682 dh, len);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700683 break;
684 }
685
Arnaldo Carvalho de Melo7690af32005-08-13 20:34:54 -0300686 if (dh->dccph_type == DCCP_PKT_ACK ||
687 dh->dccph_type == DCCP_PKT_DATAACK) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700688 switch (old_state) {
689 case DCCP_PARTOPEN:
690 sk->sk_state_change(sk);
Pavel Emelyanov8d8ad9d2007-11-26 20:10:50 +0800691 sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700692 break;
693 }
Gerrit Renker08831702007-09-26 10:30:05 -0300694 } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
695 dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
696 goto discard;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700697 }
698
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200699 if (!queued) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700700discard:
701 __kfree_skb(skb);
702 }
703 return 0;
704}
Arnaldo Carvalho de Melof21e68c2005-12-13 23:24:16 -0800705
706EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
Gerrit Renker4712a792007-03-20 15:23:18 -0300707
708/**
Gerrit Renker3393da82007-09-25 22:40:44 -0700709 * dccp_sample_rtt - Validate and finalise computation of RTT sample
710 * @delta: number of microseconds between packet and acknowledgment
711 * The routine is kept generic to work in different contexts. It should be
712 * called immediately when the ACK used for the RTT sample arrives.
Gerrit Renker4712a792007-03-20 15:23:18 -0300713 */
Gerrit Renker3393da82007-09-25 22:40:44 -0700714u32 dccp_sample_rtt(struct sock *sk, long delta)
Gerrit Renker4712a792007-03-20 15:23:18 -0300715{
Gerrit Renker3393da82007-09-25 22:40:44 -0700716 /* dccpor_elapsed_time is either zeroed out or set and > 0 */
717 delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
Gerrit Renker4712a792007-03-20 15:23:18 -0300718
Gerrit Renker410e27a2008-09-09 13:27:22 +0200719 if (unlikely(delta <= 0)) {
720 DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
721 return DCCP_SANE_RTT_MIN;
722 }
723 if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
724 DCCP_WARN("RTT sample %ld too large, using max\n", delta);
725 return DCCP_SANE_RTT_MAX;
726 }
727
728 return delta;
Gerrit Renker4712a792007-03-20 15:23:18 -0300729}
730
731EXPORT_SYMBOL_GPL(dccp_sample_rtt);