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Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/output.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 | 13 | #include <linux/dccp.h> |
48918a4d | 14 | #include <linux/kernel.h> |
7c657876 ACM |
15 | #include <linux/skbuff.h> |
16 | ||
14c85021 | 17 | #include <net/inet_sock.h> |
7c657876 ACM |
18 | #include <net/sock.h> |
19 | ||
ae31c339 | 20 | #include "ackvec.h" |
7c657876 ACM |
21 | #include "ccid.h" |
22 | #include "dccp.h" | |
23 | ||
24 | static inline void dccp_event_ack_sent(struct sock *sk) | |
25 | { | |
26 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
27 | } | |
28 | ||
c25a18ba | 29 | static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb) |
48918a4d HX |
30 | { |
31 | skb_set_owner_w(skb, sk); | |
32 | WARN_ON(sk->sk_send_head); | |
33 | sk->sk_send_head = skb; | |
34 | } | |
35 | ||
7c657876 ACM |
36 | /* |
37 | * All SKB's seen here are completely headerless. It is our | |
38 | * job to build the DCCP header, and pass the packet down to | |
39 | * IP so it can do the same plus pass the packet off to the | |
40 | * device. | |
41 | */ | |
48918a4d | 42 | static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
43 | { |
44 | if (likely(skb != NULL)) { | |
45 | const struct inet_sock *inet = inet_sk(sk); | |
57cca05a | 46 | const struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 ACM |
47 | struct dccp_sock *dp = dccp_sk(sk); |
48 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
49 | struct dccp_hdr *dh; | |
50 | /* XXX For now we're using only 48 bits sequence numbers */ | |
118b2c95 | 51 | const u32 dccp_header_size = sizeof(*dh) + |
7c657876 | 52 | sizeof(struct dccp_hdr_ext) + |
7690af3f | 53 | dccp_packet_hdr_len(dcb->dccpd_type); |
7c657876 ACM |
54 | int err, set_ack = 1; |
55 | u64 ackno = dp->dccps_gsr; | |
56 | ||
7c657876 ACM |
57 | dccp_inc_seqno(&dp->dccps_gss); |
58 | ||
7c657876 ACM |
59 | switch (dcb->dccpd_type) { |
60 | case DCCP_PKT_DATA: | |
61 | set_ack = 0; | |
edc9e819 HX |
62 | /* fall through */ |
63 | case DCCP_PKT_DATAACK: | |
ee1a1592 | 64 | case DCCP_PKT_RESET: |
7c657876 | 65 | break; |
edc9e819 | 66 | |
afe00251 AB |
67 | case DCCP_PKT_REQUEST: |
68 | set_ack = 0; | |
69 | /* fall through */ | |
70 | ||
7c657876 ACM |
71 | case DCCP_PKT_SYNC: |
72 | case DCCP_PKT_SYNCACK: | |
b0d045ca | 73 | ackno = dcb->dccpd_ack_seq; |
edc9e819 HX |
74 | /* fall through */ |
75 | default: | |
76 | /* | |
ee1a1592 GR |
77 | * Set owner/destructor: some skbs are allocated via |
78 | * alloc_skb (e.g. when retransmission may happen). | |
79 | * Only Data, DataAck, and Reset packets should come | |
80 | * through here with skb->sk set. | |
edc9e819 HX |
81 | */ |
82 | WARN_ON(skb->sk); | |
83 | skb_set_owner_w(skb, sk); | |
7c657876 ACM |
84 | break; |
85 | } | |
24117727 ACM |
86 | |
87 | dcb->dccpd_seq = dp->dccps_gss; | |
2d0817d1 ACM |
88 | |
89 | if (dccp_insert_options(sk, skb)) { | |
90 | kfree_skb(skb); | |
91 | return -EPROTO; | |
92 | } | |
c9eaf173 | 93 | |
fda0fd6c | 94 | |
7c657876 | 95 | /* Build DCCP header and checksum it. */ |
9b42078e | 96 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 ACM |
97 | dh->dccph_type = dcb->dccpd_type; |
98 | dh->dccph_sport = inet->sport; | |
99 | dh->dccph_dport = inet->dport; | |
100 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; | |
101 | dh->dccph_ccval = dcb->dccpd_ccval; | |
6f4e5fff | 102 | dh->dccph_cscov = dp->dccps_pcslen; |
7c657876 ACM |
103 | /* XXX For now we're using only 48 bits sequence numbers */ |
104 | dh->dccph_x = 1; | |
105 | ||
106 | dp->dccps_awh = dp->dccps_gss; | |
107 | dccp_hdr_set_seq(dh, dp->dccps_gss); | |
108 | if (set_ack) | |
109 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
110 | ||
111 | switch (dcb->dccpd_type) { | |
112 | case DCCP_PKT_REQUEST: | |
7690af3f | 113 | dccp_hdr_request(skb)->dccph_req_service = |
67e6b629 | 114 | dp->dccps_service; |
7c657876 ACM |
115 | break; |
116 | case DCCP_PKT_RESET: | |
7690af3f ACM |
117 | dccp_hdr_reset(skb)->dccph_reset_code = |
118 | dcb->dccpd_reset_code; | |
7c657876 ACM |
119 | break; |
120 | } | |
121 | ||
6f4e5fff | 122 | icsk->icsk_af_ops->send_check(sk, 0, skb); |
7c657876 | 123 | |
7ad07e7c | 124 | if (set_ack) |
7c657876 ACM |
125 | dccp_event_ack_sent(sk); |
126 | ||
127 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
128 | ||
e89862f4 | 129 | err = icsk->icsk_af_ops->queue_xmit(skb, 0); |
b9df3cb8 | 130 | return net_xmit_eval(err); |
7c657876 ACM |
131 | } |
132 | return -ENOBUFS; | |
133 | } | |
134 | ||
6179983a GR |
135 | /** |
136 | * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits | |
137 | * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), | |
138 | * since the RX CCID is restricted to feedback packets (Acks), which are small | |
139 | * in comparison with the data traffic. A value of 0 means "no current CCMPS". | |
140 | */ | |
141 | static u32 dccp_determine_ccmps(const struct dccp_sock *dp) | |
142 | { | |
143 | const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; | |
144 | ||
145 | if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) | |
146 | return 0; | |
147 | return tx_ccid->ccid_ops->ccid_ccmps; | |
148 | } | |
149 | ||
7c657876 ACM |
150 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
151 | { | |
d83d8461 | 152 | struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 | 153 | struct dccp_sock *dp = dccp_sk(sk); |
6179983a GR |
154 | u32 ccmps = dccp_determine_ccmps(dp); |
155 | int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; | |
7c657876 | 156 | |
6179983a GR |
157 | /* Account for header lengths and IPv4/v6 option overhead */ |
158 | cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + | |
159 | sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); | |
7c657876 ACM |
160 | |
161 | /* | |
162 | * FIXME: this should come from the CCID infrastructure, where, say, | |
163 | * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets | |
164 | * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED | |
165 | * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to | |
166 | * make it a multiple of 4 | |
167 | */ | |
168 | ||
6179983a | 169 | cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4; |
7c657876 ACM |
170 | |
171 | /* And store cached results */ | |
d83d8461 | 172 | icsk->icsk_pmtu_cookie = pmtu; |
6179983a | 173 | dp->dccps_mss_cache = cur_mps; |
7c657876 | 174 | |
6179983a | 175 | return cur_mps; |
7c657876 ACM |
176 | } |
177 | ||
f21e68ca ACM |
178 | EXPORT_SYMBOL_GPL(dccp_sync_mss); |
179 | ||
c530cfb1 ACM |
180 | void dccp_write_space(struct sock *sk) |
181 | { | |
182 | read_lock(&sk->sk_callback_lock); | |
183 | ||
184 | if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) | |
185 | wake_up_interruptible(sk->sk_sleep); | |
186 | /* Should agree with poll, otherwise some programs break */ | |
187 | if (sock_writeable(sk)) | |
8d8ad9d7 | 188 | sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
c530cfb1 ACM |
189 | |
190 | read_unlock(&sk->sk_callback_lock); | |
191 | } | |
192 | ||
d6809c12 ACM |
193 | /** |
194 | * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet | |
bc849872 GR |
195 | * @sk: socket to wait for |
196 | * @skb: current skb to pass on for waiting | |
197 | * @delay: sleep timeout in milliseconds (> 0) | |
198 | * This function is called by default when the socket is closed, and | |
199 | * when a non-zero linger time is set on the socket. For consistency | |
d6809c12 | 200 | */ |
bc849872 | 201 | static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) |
d6809c12 ACM |
202 | { |
203 | struct dccp_sock *dp = dccp_sk(sk); | |
204 | DEFINE_WAIT(wait); | |
bc849872 | 205 | unsigned long jiffdelay; |
d6809c12 ACM |
206 | int rc; |
207 | ||
bc849872 GR |
208 | do { |
209 | dccp_pr_debug("delayed send by %d msec\n", delay); | |
210 | jiffdelay = msecs_to_jiffies(delay); | |
211 | ||
d6809c12 ACM |
212 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); |
213 | ||
bc849872 GR |
214 | sk->sk_write_pending++; |
215 | release_sock(sk); | |
216 | schedule_timeout(jiffdelay); | |
217 | lock_sock(sk); | |
218 | sk->sk_write_pending--; | |
219 | ||
97e5848d | 220 | if (sk->sk_err) |
d6809c12 | 221 | goto do_error; |
d6809c12 ACM |
222 | if (signal_pending(current)) |
223 | goto do_interrupted; | |
224 | ||
6b57c93d | 225 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
bc849872 | 226 | } while ((delay = rc) > 0); |
d6809c12 ACM |
227 | out: |
228 | finish_wait(sk->sk_sleep, &wait); | |
229 | return rc; | |
230 | ||
231 | do_error: | |
232 | rc = -EPIPE; | |
233 | goto out; | |
d6809c12 | 234 | do_interrupted: |
5cc3741d | 235 | rc = -EINTR; |
d6809c12 ACM |
236 | goto out; |
237 | } | |
238 | ||
97e5848d | 239 | void dccp_write_xmit(struct sock *sk, int block) |
27258ee5 | 240 | { |
97e5848d IM |
241 | struct dccp_sock *dp = dccp_sk(sk); |
242 | struct sk_buff *skb; | |
97e5848d IM |
243 | |
244 | while ((skb = skb_peek(&sk->sk_write_queue))) { | |
6b57c93d | 245 | int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
d6809c12 | 246 | |
97e5848d IM |
247 | if (err > 0) { |
248 | if (!block) { | |
249 | sk_reset_timer(sk, &dp->dccps_xmit_timer, | |
250 | msecs_to_jiffies(err)+jiffies); | |
251 | break; | |
5cc3741d | 252 | } else |
bc849872 | 253 | err = dccp_wait_for_ccid(sk, skb, err); |
f6282f4d | 254 | if (err && err != -EINTR) |
59348b19 | 255 | DCCP_BUG("err=%d after dccp_wait_for_ccid", err); |
97e5848d | 256 | } |
27258ee5 | 257 | |
97e5848d IM |
258 | skb_dequeue(&sk->sk_write_queue); |
259 | if (err == 0) { | |
260 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
261 | const int len = skb->len; | |
27258ee5 | 262 | |
97e5848d IM |
263 | if (sk->sk_state == DCCP_PARTOPEN) { |
264 | /* See 8.1.5. Handshake Completion */ | |
265 | inet_csk_schedule_ack(sk); | |
266 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
27258ee5 ACM |
267 | inet_csk(sk)->icsk_rto, |
268 | DCCP_RTO_MAX); | |
97e5848d IM |
269 | dcb->dccpd_type = DCCP_PKT_DATAACK; |
270 | } else if (dccp_ack_pending(sk)) | |
271 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
272 | else | |
273 | dcb->dccpd_type = DCCP_PKT_DATA; | |
274 | ||
275 | err = dccp_transmit_skb(sk, skb); | |
276 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); | |
59348b19 GR |
277 | if (err) |
278 | DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", | |
279 | err); | |
f6282f4d | 280 | } else { |
6626e362 | 281 | dccp_pr_debug("packet discarded due to err=%d\n", err); |
b08d5840 | 282 | kfree_skb(skb); |
f6282f4d | 283 | } |
97e5848d | 284 | } |
27258ee5 ACM |
285 | } |
286 | ||
59435444 GR |
287 | /** |
288 | * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets | |
289 | * There are only four retransmittable packet types in DCCP: | |
290 | * - Request in client-REQUEST state (sec. 8.1.1), | |
291 | * - CloseReq in server-CLOSEREQ state (sec. 8.3), | |
292 | * - Close in node-CLOSING state (sec. 8.3), | |
293 | * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). | |
294 | * This function expects sk->sk_send_head to contain the original skb. | |
295 | */ | |
296 | int dccp_retransmit_skb(struct sock *sk) | |
7c657876 | 297 | { |
59435444 GR |
298 | WARN_ON(sk->sk_send_head == NULL); |
299 | ||
57cca05a | 300 | if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) |
7c657876 ACM |
301 | return -EHOSTUNREACH; /* Routing failure or similar. */ |
302 | ||
59435444 GR |
303 | /* this count is used to distinguish original and retransmitted skb */ |
304 | inet_csk(sk)->icsk_retransmits++; | |
305 | ||
306 | return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); | |
7c657876 ACM |
307 | } |
308 | ||
309 | struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, | |
310 | struct request_sock *req) | |
311 | { | |
312 | struct dccp_hdr *dh; | |
67e6b629 | 313 | struct dccp_request_sock *dreq; |
118b2c95 | 314 | const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
7c657876 ACM |
315 | sizeof(struct dccp_hdr_ext) + |
316 | sizeof(struct dccp_hdr_response); | |
118b2c95 | 317 | struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, |
7c657876 ACM |
318 | GFP_ATOMIC); |
319 | if (skb == NULL) | |
320 | return NULL; | |
321 | ||
322 | /* Reserve space for headers. */ | |
118b2c95 | 323 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
324 | |
325 | skb->dst = dst_clone(dst); | |
7c657876 | 326 | |
67e6b629 | 327 | dreq = dccp_rsk(req); |
e11d9d30 GR |
328 | if (inet_rsk(req)->acked) /* increase ISS upon retransmission */ |
329 | dccp_inc_seqno(&dreq->dreq_iss); | |
7c657876 | 330 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
67e6b629 | 331 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; |
2d0817d1 | 332 | |
af3b867e | 333 | if (dccp_insert_options_rsk(dreq, skb)) { |
2d0817d1 ACM |
334 | kfree_skb(skb); |
335 | return NULL; | |
336 | } | |
7c657876 | 337 | |
09dbc389 | 338 | /* Build and checksum header */ |
9b42078e | 339 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 ACM |
340 | |
341 | dh->dccph_sport = inet_sk(sk)->sport; | |
342 | dh->dccph_dport = inet_rsk(req)->rmt_port; | |
7690af3f ACM |
343 | dh->dccph_doff = (dccp_header_size + |
344 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
345 | dh->dccph_type = DCCP_PKT_RESPONSE; |
346 | dh->dccph_x = 1; | |
67e6b629 ACM |
347 | dccp_hdr_set_seq(dh, dreq->dreq_iss); |
348 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr); | |
349 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; | |
7c657876 | 350 | |
6f4e5fff GR |
351 | dccp_csum_outgoing(skb); |
352 | ||
e11d9d30 GR |
353 | /* We use `acked' to remember that a Response was already sent. */ |
354 | inet_rsk(req)->acked = 1; | |
7c657876 ACM |
355 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
356 | return skb; | |
357 | } | |
358 | ||
f21e68ca ACM |
359 | EXPORT_SYMBOL_GPL(dccp_make_response); |
360 | ||
e356d37a | 361 | /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
7630f026 | 362 | struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
e356d37a GR |
363 | { |
364 | struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; | |
365 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); | |
366 | const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + | |
367 | sizeof(struct dccp_hdr_ext) + | |
368 | sizeof(struct dccp_hdr_reset); | |
369 | struct dccp_hdr_reset *dhr; | |
370 | struct sk_buff *skb; | |
371 | ||
7630f026 | 372 | skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
e356d37a GR |
373 | if (skb == NULL) |
374 | return NULL; | |
375 | ||
7630f026 | 376 | skb_reserve(skb, sk->sk_prot->max_header); |
e356d37a GR |
377 | |
378 | /* Swap the send and the receive. */ | |
379 | dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); | |
380 | dh->dccph_type = DCCP_PKT_RESET; | |
381 | dh->dccph_sport = rxdh->dccph_dport; | |
382 | dh->dccph_dport = rxdh->dccph_sport; | |
383 | dh->dccph_doff = dccp_hdr_reset_len / 4; | |
384 | dh->dccph_x = 1; | |
385 | ||
386 | dhr = dccp_hdr_reset(skb); | |
387 | dhr->dccph_reset_code = dcb->dccpd_reset_code; | |
388 | ||
389 | switch (dcb->dccpd_reset_code) { | |
390 | case DCCP_RESET_CODE_PACKET_ERROR: | |
391 | dhr->dccph_reset_data[0] = rxdh->dccph_type; | |
392 | break; | |
393 | case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */ | |
394 | case DCCP_RESET_CODE_MANDATORY_ERROR: | |
395 | memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); | |
396 | break; | |
397 | } | |
398 | /* | |
399 | * From RFC 4340, 8.3.1: | |
400 | * If P.ackno exists, set R.seqno := P.ackno + 1. | |
401 | * Else set R.seqno := 0. | |
402 | */ | |
403 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
404 | dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); | |
405 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); | |
406 | ||
407 | dccp_csum_outgoing(skb); | |
408 | return skb; | |
409 | } | |
410 | ||
411 | EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); | |
412 | ||
ee1a1592 | 413 | /* send Reset on established socket, to close or abort the connection */ |
017487d7 ACM |
414 | int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
415 | { | |
ee1a1592 | 416 | struct sk_buff *skb; |
017487d7 ACM |
417 | /* |
418 | * FIXME: what if rebuild_header fails? | |
419 | * Should we be doing a rebuild_header here? | |
420 | */ | |
f53dc67c | 421 | int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
017487d7 | 422 | |
ee1a1592 GR |
423 | if (err != 0) |
424 | return err; | |
425 | ||
426 | skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); | |
427 | if (skb == NULL) | |
428 | return -ENOBUFS; | |
429 | ||
430 | /* Reserve space for headers and prepare control bits. */ | |
431 | skb_reserve(skb, sk->sk_prot->max_header); | |
432 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
433 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
017487d7 | 434 | |
ee1a1592 | 435 | return dccp_transmit_skb(sk, skb); |
017487d7 ACM |
436 | } |
437 | ||
7c657876 ACM |
438 | /* |
439 | * Do all connect socket setups that can be done AF independent. | |
440 | */ | |
441 | static inline void dccp_connect_init(struct sock *sk) | |
442 | { | |
f21e68ca | 443 | struct dccp_sock *dp = dccp_sk(sk); |
7c657876 ACM |
444 | struct dst_entry *dst = __sk_dst_get(sk); |
445 | struct inet_connection_sock *icsk = inet_csk(sk); | |
446 | ||
447 | sk->sk_err = 0; | |
448 | sock_reset_flag(sk, SOCK_DONE); | |
c9eaf173 | 449 | |
7c657876 ACM |
450 | dccp_sync_mss(sk, dst_mtu(dst)); |
451 | ||
8109b02b | 452 | /* |
f21e68ca ACM |
453 | * SWL and AWL are initially adjusted so that they are not less than |
454 | * the initial Sequence Numbers received and sent, respectively: | |
455 | * SWL := max(GSR + 1 - floor(W/4), ISR), | |
456 | * AWL := max(GSS - W' + 1, ISS). | |
457 | * These adjustments MUST be applied only at the beginning of the | |
458 | * connection. | |
8109b02b | 459 | */ |
d7f7365f | 460 | dccp_update_gss(sk, dp->dccps_iss); |
f21e68ca | 461 | dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss)); |
7c657876 | 462 | |
d7f7365f GR |
463 | /* S.GAR - greatest valid acknowledgement number received on a non-Sync; |
464 | * initialized to S.ISS (sec. 8.5) */ | |
465 | dp->dccps_gar = dp->dccps_iss; | |
466 | ||
7c657876 ACM |
467 | icsk->icsk_retransmits = 0; |
468 | } | |
469 | ||
470 | int dccp_connect(struct sock *sk) | |
471 | { | |
472 | struct sk_buff *skb; | |
473 | struct inet_connection_sock *icsk = inet_csk(sk); | |
474 | ||
475 | dccp_connect_init(sk); | |
476 | ||
118b2c95 | 477 | skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
7c657876 ACM |
478 | if (unlikely(skb == NULL)) |
479 | return -ENOBUFS; | |
480 | ||
481 | /* Reserve space for headers. */ | |
118b2c95 | 482 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
483 | |
484 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 | 485 | |
48918a4d | 486 | dccp_skb_entail(sk, skb); |
7c657876 ACM |
487 | dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); |
488 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); | |
489 | ||
490 | /* Timer for repeating the REQUEST until an answer. */ | |
27258ee5 ACM |
491 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
492 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
493 | return 0; |
494 | } | |
495 | ||
f21e68ca ACM |
496 | EXPORT_SYMBOL_GPL(dccp_connect); |
497 | ||
7c657876 ACM |
498 | void dccp_send_ack(struct sock *sk) |
499 | { | |
500 | /* If we have been reset, we may not send again. */ | |
501 | if (sk->sk_state != DCCP_CLOSED) { | |
118b2c95 ACM |
502 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
503 | GFP_ATOMIC); | |
7c657876 ACM |
504 | |
505 | if (skb == NULL) { | |
506 | inet_csk_schedule_ack(sk); | |
507 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
508 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
509 | TCP_DELACK_MAX, | |
510 | DCCP_RTO_MAX); | |
7c657876 ACM |
511 | return; |
512 | } | |
513 | ||
514 | /* Reserve space for headers */ | |
118b2c95 | 515 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 516 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
7c657876 ACM |
517 | dccp_transmit_skb(sk, skb); |
518 | } | |
519 | } | |
520 | ||
521 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
522 | ||
1e2f0e5e | 523 | #if 0 |
727ecc5f | 524 | /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
7c657876 ACM |
525 | void dccp_send_delayed_ack(struct sock *sk) |
526 | { | |
527 | struct inet_connection_sock *icsk = inet_csk(sk); | |
528 | /* | |
529 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
530 | * with using 2s, and active senders also piggyback the ACK into a | |
531 | * DATAACK packet, so this is really for quiescent senders. | |
532 | */ | |
533 | unsigned long timeout = jiffies + 2 * HZ; | |
534 | ||
535 | /* Use new timeout only if there wasn't a older one earlier. */ | |
536 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
537 | /* If delack timer was blocked or is about to expire, | |
538 | * send ACK now. | |
539 | * | |
540 | * FIXME: check the "about to expire" part | |
541 | */ | |
542 | if (icsk->icsk_ack.blocked) { | |
543 | dccp_send_ack(sk); | |
544 | return; | |
545 | } | |
546 | ||
547 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
548 | timeout = icsk->icsk_ack.timeout; | |
549 | } | |
550 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
551 | icsk->icsk_ack.timeout = timeout; | |
552 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
553 | } | |
1e2f0e5e | 554 | #endif |
7c657876 | 555 | |
b0d045ca | 556 | void dccp_send_sync(struct sock *sk, const u64 ackno, |
e92ae93a | 557 | const enum dccp_pkt_type pkt_type) |
7c657876 ACM |
558 | { |
559 | /* | |
560 | * We are not putting this on the write queue, so | |
561 | * dccp_transmit_skb() will set the ownership to this | |
562 | * sock. | |
563 | */ | |
118b2c95 | 564 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
7c657876 | 565 | |
b0d045ca | 566 | if (skb == NULL) { |
7c657876 | 567 | /* FIXME: how to make sure the sync is sent? */ |
b0d045ca | 568 | DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
7c657876 | 569 | return; |
b0d045ca | 570 | } |
7c657876 ACM |
571 | |
572 | /* Reserve space for headers and prepare control bits. */ | |
118b2c95 | 573 | skb_reserve(skb, sk->sk_prot->max_header); |
e92ae93a | 574 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
b0d045ca | 575 | DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
7c657876 | 576 | |
7c657876 ACM |
577 | dccp_transmit_skb(sk, skb); |
578 | } | |
579 | ||
b61fafc4 ACM |
580 | EXPORT_SYMBOL_GPL(dccp_send_sync); |
581 | ||
7690af3f ACM |
582 | /* |
583 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
584 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
585 | * any circumstances. | |
7c657876 | 586 | */ |
7ad07e7c | 587 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
588 | { |
589 | struct dccp_sock *dp = dccp_sk(sk); | |
590 | struct sk_buff *skb; | |
7d877f3b | 591 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 592 | |
7ad07e7c ACM |
593 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
594 | if (skb == NULL) | |
595 | return; | |
7c657876 ACM |
596 | |
597 | /* Reserve space for headers and prepare control bits. */ | |
598 | skb_reserve(skb, sk->sk_prot->max_header); | |
b8599d20 GR |
599 | if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
600 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; | |
601 | else | |
602 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; | |
7c657876 | 603 | |
7ad07e7c | 604 | if (active) { |
97e5848d | 605 | dccp_write_xmit(sk, 1); |
48918a4d | 606 | dccp_skb_entail(sk, skb); |
7ad07e7c | 607 | dccp_transmit_skb(sk, skb_clone(skb, prio)); |
92d31920 GR |
608 | /* |
609 | * Retransmission timer for active-close: RFC 4340, 8.3 requires | |
610 | * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ | |
611 | * state can be left. The initial timeout is 2 RTTs. | |
612 | * Since RTT measurement is done by the CCIDs, there is no easy | |
613 | * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 | |
614 | * is too low (200ms); we use a high value to avoid unnecessary | |
615 | * retransmissions when the link RTT is > 0.2 seconds. | |
616 | * FIXME: Let main module sample RTTs and use that instead. | |
617 | */ | |
618 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
619 | DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); | |
7ad07e7c ACM |
620 | } else |
621 | dccp_transmit_skb(sk, skb); | |
7c657876 | 622 | } |