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; | |
73f18fdb GR |
56 | /* |
57 | * Increment GSS here already in case the option code needs it. | |
58 | * Update GSS for real only if option processing below succeeds. | |
59 | */ | |
60 | dcb->dccpd_seq = ADD48(dp->dccps_gss, 1); | |
7c657876 | 61 | |
7c657876 ACM |
62 | switch (dcb->dccpd_type) { |
63 | case DCCP_PKT_DATA: | |
64 | set_ack = 0; | |
edc9e819 HX |
65 | /* fall through */ |
66 | case DCCP_PKT_DATAACK: | |
ee1a1592 | 67 | case DCCP_PKT_RESET: |
7c657876 | 68 | break; |
edc9e819 | 69 | |
afe00251 AB |
70 | case DCCP_PKT_REQUEST: |
71 | set_ack = 0; | |
73f18fdb GR |
72 | /* Use ISS on the first (non-retransmitted) Request. */ |
73 | if (icsk->icsk_retransmits == 0) | |
74 | dcb->dccpd_seq = dp->dccps_iss; | |
afe00251 AB |
75 | /* fall through */ |
76 | ||
7c657876 ACM |
77 | case DCCP_PKT_SYNC: |
78 | case DCCP_PKT_SYNCACK: | |
b0d045ca | 79 | ackno = dcb->dccpd_ack_seq; |
edc9e819 HX |
80 | /* fall through */ |
81 | default: | |
82 | /* | |
ee1a1592 GR |
83 | * Set owner/destructor: some skbs are allocated via |
84 | * alloc_skb (e.g. when retransmission may happen). | |
85 | * Only Data, DataAck, and Reset packets should come | |
86 | * through here with skb->sk set. | |
edc9e819 HX |
87 | */ |
88 | WARN_ON(skb->sk); | |
89 | skb_set_owner_w(skb, sk); | |
7c657876 ACM |
90 | break; |
91 | } | |
24117727 | 92 | |
2d0817d1 ACM |
93 | if (dccp_insert_options(sk, skb)) { |
94 | kfree_skb(skb); | |
95 | return -EPROTO; | |
96 | } | |
c9eaf173 | 97 | |
fda0fd6c | 98 | |
7c657876 | 99 | /* Build DCCP header and checksum it. */ |
9b42078e | 100 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 ACM |
101 | dh->dccph_type = dcb->dccpd_type; |
102 | dh->dccph_sport = inet->sport; | |
103 | dh->dccph_dport = inet->dport; | |
104 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; | |
105 | dh->dccph_ccval = dcb->dccpd_ccval; | |
6f4e5fff | 106 | dh->dccph_cscov = dp->dccps_pcslen; |
7c657876 ACM |
107 | /* XXX For now we're using only 48 bits sequence numbers */ |
108 | dh->dccph_x = 1; | |
109 | ||
73f18fdb | 110 | dccp_update_gss(sk, dcb->dccpd_seq); |
7c657876 ACM |
111 | dccp_hdr_set_seq(dh, dp->dccps_gss); |
112 | if (set_ack) | |
113 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
114 | ||
115 | switch (dcb->dccpd_type) { | |
116 | case DCCP_PKT_REQUEST: | |
7690af3f | 117 | dccp_hdr_request(skb)->dccph_req_service = |
67e6b629 | 118 | dp->dccps_service; |
73f18fdb GR |
119 | /* |
120 | * Limit Ack window to ISS <= P.ackno <= GSS, so that | |
121 | * only Responses to Requests we sent are considered. | |
122 | */ | |
123 | dp->dccps_awl = dp->dccps_iss; | |
7c657876 ACM |
124 | break; |
125 | case DCCP_PKT_RESET: | |
7690af3f ACM |
126 | dccp_hdr_reset(skb)->dccph_reset_code = |
127 | dcb->dccpd_reset_code; | |
7c657876 ACM |
128 | break; |
129 | } | |
130 | ||
6f4e5fff | 131 | icsk->icsk_af_ops->send_check(sk, 0, skb); |
7c657876 | 132 | |
7ad07e7c | 133 | if (set_ack) |
7c657876 ACM |
134 | dccp_event_ack_sent(sk); |
135 | ||
136 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
137 | ||
e89862f4 | 138 | err = icsk->icsk_af_ops->queue_xmit(skb, 0); |
b9df3cb8 | 139 | return net_xmit_eval(err); |
7c657876 ACM |
140 | } |
141 | return -ENOBUFS; | |
142 | } | |
143 | ||
6179983a GR |
144 | /** |
145 | * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits | |
146 | * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), | |
147 | * since the RX CCID is restricted to feedback packets (Acks), which are small | |
148 | * in comparison with the data traffic. A value of 0 means "no current CCMPS". | |
149 | */ | |
150 | static u32 dccp_determine_ccmps(const struct dccp_sock *dp) | |
151 | { | |
152 | const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; | |
153 | ||
154 | if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) | |
155 | return 0; | |
156 | return tx_ccid->ccid_ops->ccid_ccmps; | |
157 | } | |
158 | ||
7c657876 ACM |
159 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
160 | { | |
d83d8461 | 161 | struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 | 162 | struct dccp_sock *dp = dccp_sk(sk); |
6179983a GR |
163 | u32 ccmps = dccp_determine_ccmps(dp); |
164 | int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; | |
7c657876 | 165 | |
6179983a GR |
166 | /* Account for header lengths and IPv4/v6 option overhead */ |
167 | cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + | |
168 | sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); | |
7c657876 ACM |
169 | |
170 | /* | |
171 | * FIXME: this should come from the CCID infrastructure, where, say, | |
172 | * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets | |
173 | * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED | |
174 | * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to | |
175 | * make it a multiple of 4 | |
176 | */ | |
177 | ||
61c1d052 | 178 | cur_mps -= roundup(5 + 6 + 10 + 6 + 6 + 6, 4); |
7c657876 ACM |
179 | |
180 | /* And store cached results */ | |
d83d8461 | 181 | icsk->icsk_pmtu_cookie = pmtu; |
6179983a | 182 | dp->dccps_mss_cache = cur_mps; |
7c657876 | 183 | |
6179983a | 184 | return cur_mps; |
7c657876 ACM |
185 | } |
186 | ||
f21e68ca ACM |
187 | EXPORT_SYMBOL_GPL(dccp_sync_mss); |
188 | ||
c530cfb1 ACM |
189 | void dccp_write_space(struct sock *sk) |
190 | { | |
191 | read_lock(&sk->sk_callback_lock); | |
192 | ||
193 | if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) | |
194 | wake_up_interruptible(sk->sk_sleep); | |
195 | /* Should agree with poll, otherwise some programs break */ | |
196 | if (sock_writeable(sk)) | |
8d8ad9d7 | 197 | sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
c530cfb1 ACM |
198 | |
199 | read_unlock(&sk->sk_callback_lock); | |
200 | } | |
201 | ||
d6809c12 ACM |
202 | /** |
203 | * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet | |
bc849872 GR |
204 | * @sk: socket to wait for |
205 | * @skb: current skb to pass on for waiting | |
206 | * @delay: sleep timeout in milliseconds (> 0) | |
207 | * This function is called by default when the socket is closed, and | |
208 | * when a non-zero linger time is set on the socket. For consistency | |
d6809c12 | 209 | */ |
bc849872 | 210 | static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) |
d6809c12 ACM |
211 | { |
212 | struct dccp_sock *dp = dccp_sk(sk); | |
213 | DEFINE_WAIT(wait); | |
bc849872 | 214 | unsigned long jiffdelay; |
d6809c12 ACM |
215 | int rc; |
216 | ||
bc849872 GR |
217 | do { |
218 | dccp_pr_debug("delayed send by %d msec\n", delay); | |
219 | jiffdelay = msecs_to_jiffies(delay); | |
220 | ||
d6809c12 ACM |
221 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); |
222 | ||
bc849872 GR |
223 | sk->sk_write_pending++; |
224 | release_sock(sk); | |
225 | schedule_timeout(jiffdelay); | |
226 | lock_sock(sk); | |
227 | sk->sk_write_pending--; | |
228 | ||
97e5848d | 229 | if (sk->sk_err) |
d6809c12 | 230 | goto do_error; |
d6809c12 ACM |
231 | if (signal_pending(current)) |
232 | goto do_interrupted; | |
233 | ||
6b57c93d | 234 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
bc849872 | 235 | } while ((delay = rc) > 0); |
d6809c12 ACM |
236 | out: |
237 | finish_wait(sk->sk_sleep, &wait); | |
238 | return rc; | |
239 | ||
240 | do_error: | |
241 | rc = -EPIPE; | |
242 | goto out; | |
d6809c12 | 243 | do_interrupted: |
5cc3741d | 244 | rc = -EINTR; |
d6809c12 ACM |
245 | goto out; |
246 | } | |
247 | ||
97e5848d | 248 | void dccp_write_xmit(struct sock *sk, int block) |
27258ee5 | 249 | { |
97e5848d IM |
250 | struct dccp_sock *dp = dccp_sk(sk); |
251 | struct sk_buff *skb; | |
97e5848d IM |
252 | |
253 | while ((skb = skb_peek(&sk->sk_write_queue))) { | |
6b57c93d | 254 | int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
d6809c12 | 255 | |
97e5848d IM |
256 | if (err > 0) { |
257 | if (!block) { | |
258 | sk_reset_timer(sk, &dp->dccps_xmit_timer, | |
259 | msecs_to_jiffies(err)+jiffies); | |
260 | break; | |
5cc3741d | 261 | } else |
bc849872 | 262 | err = dccp_wait_for_ccid(sk, skb, err); |
f6282f4d | 263 | if (err && err != -EINTR) |
59348b19 | 264 | DCCP_BUG("err=%d after dccp_wait_for_ccid", err); |
97e5848d | 265 | } |
27258ee5 | 266 | |
97e5848d IM |
267 | skb_dequeue(&sk->sk_write_queue); |
268 | if (err == 0) { | |
269 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
270 | const int len = skb->len; | |
27258ee5 | 271 | |
97e5848d IM |
272 | if (sk->sk_state == DCCP_PARTOPEN) { |
273 | /* See 8.1.5. Handshake Completion */ | |
274 | inet_csk_schedule_ack(sk); | |
275 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
27258ee5 ACM |
276 | inet_csk(sk)->icsk_rto, |
277 | DCCP_RTO_MAX); | |
97e5848d IM |
278 | dcb->dccpd_type = DCCP_PKT_DATAACK; |
279 | } else if (dccp_ack_pending(sk)) | |
280 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
281 | else | |
282 | dcb->dccpd_type = DCCP_PKT_DATA; | |
283 | ||
284 | err = dccp_transmit_skb(sk, skb); | |
285 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); | |
59348b19 GR |
286 | if (err) |
287 | DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", | |
288 | err); | |
f6282f4d | 289 | } else { |
6626e362 | 290 | dccp_pr_debug("packet discarded due to err=%d\n", err); |
b08d5840 | 291 | kfree_skb(skb); |
f6282f4d | 292 | } |
97e5848d | 293 | } |
27258ee5 ACM |
294 | } |
295 | ||
59435444 GR |
296 | /** |
297 | * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets | |
298 | * There are only four retransmittable packet types in DCCP: | |
299 | * - Request in client-REQUEST state (sec. 8.1.1), | |
300 | * - CloseReq in server-CLOSEREQ state (sec. 8.3), | |
301 | * - Close in node-CLOSING state (sec. 8.3), | |
302 | * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). | |
303 | * This function expects sk->sk_send_head to contain the original skb. | |
304 | */ | |
305 | int dccp_retransmit_skb(struct sock *sk) | |
7c657876 | 306 | { |
59435444 GR |
307 | WARN_ON(sk->sk_send_head == NULL); |
308 | ||
57cca05a | 309 | if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) |
7c657876 ACM |
310 | return -EHOSTUNREACH; /* Routing failure or similar. */ |
311 | ||
59435444 GR |
312 | /* this count is used to distinguish original and retransmitted skb */ |
313 | inet_csk(sk)->icsk_retransmits++; | |
314 | ||
315 | return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); | |
7c657876 ACM |
316 | } |
317 | ||
318 | struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, | |
319 | struct request_sock *req) | |
320 | { | |
321 | struct dccp_hdr *dh; | |
67e6b629 | 322 | struct dccp_request_sock *dreq; |
118b2c95 | 323 | const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
7c657876 ACM |
324 | sizeof(struct dccp_hdr_ext) + |
325 | sizeof(struct dccp_hdr_response); | |
118b2c95 | 326 | struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, |
7c657876 ACM |
327 | GFP_ATOMIC); |
328 | if (skb == NULL) | |
329 | return NULL; | |
330 | ||
331 | /* Reserve space for headers. */ | |
118b2c95 | 332 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
333 | |
334 | skb->dst = dst_clone(dst); | |
7c657876 | 335 | |
67e6b629 | 336 | dreq = dccp_rsk(req); |
e11d9d30 GR |
337 | if (inet_rsk(req)->acked) /* increase ISS upon retransmission */ |
338 | dccp_inc_seqno(&dreq->dreq_iss); | |
7c657876 | 339 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
67e6b629 | 340 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; |
2d0817d1 | 341 | |
0c116839 GR |
342 | /* Resolve feature dependencies resulting from choice of CCID */ |
343 | if (dccp_feat_server_ccid_dependencies(dreq)) | |
344 | goto response_failed; | |
345 | ||
346 | if (dccp_insert_options_rsk(dreq, skb)) | |
347 | goto response_failed; | |
7c657876 | 348 | |
09dbc389 | 349 | /* Build and checksum header */ |
9b42078e | 350 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 351 | |
944f7502 | 352 | dh->dccph_sport = inet_rsk(req)->loc_port; |
7c657876 | 353 | dh->dccph_dport = inet_rsk(req)->rmt_port; |
7690af3f ACM |
354 | dh->dccph_doff = (dccp_header_size + |
355 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
356 | dh->dccph_type = DCCP_PKT_RESPONSE; |
357 | dh->dccph_x = 1; | |
67e6b629 ACM |
358 | dccp_hdr_set_seq(dh, dreq->dreq_iss); |
359 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr); | |
360 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; | |
7c657876 | 361 | |
6f4e5fff GR |
362 | dccp_csum_outgoing(skb); |
363 | ||
e11d9d30 GR |
364 | /* We use `acked' to remember that a Response was already sent. */ |
365 | inet_rsk(req)->acked = 1; | |
7c657876 ACM |
366 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
367 | return skb; | |
0c116839 GR |
368 | response_failed: |
369 | kfree_skb(skb); | |
370 | return NULL; | |
7c657876 ACM |
371 | } |
372 | ||
f21e68ca ACM |
373 | EXPORT_SYMBOL_GPL(dccp_make_response); |
374 | ||
e356d37a | 375 | /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
7630f026 | 376 | struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
e356d37a GR |
377 | { |
378 | struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; | |
379 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); | |
380 | const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + | |
381 | sizeof(struct dccp_hdr_ext) + | |
382 | sizeof(struct dccp_hdr_reset); | |
383 | struct dccp_hdr_reset *dhr; | |
384 | struct sk_buff *skb; | |
385 | ||
7630f026 | 386 | skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
e356d37a GR |
387 | if (skb == NULL) |
388 | return NULL; | |
389 | ||
7630f026 | 390 | skb_reserve(skb, sk->sk_prot->max_header); |
e356d37a GR |
391 | |
392 | /* Swap the send and the receive. */ | |
393 | dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); | |
394 | dh->dccph_type = DCCP_PKT_RESET; | |
395 | dh->dccph_sport = rxdh->dccph_dport; | |
396 | dh->dccph_dport = rxdh->dccph_sport; | |
397 | dh->dccph_doff = dccp_hdr_reset_len / 4; | |
398 | dh->dccph_x = 1; | |
399 | ||
400 | dhr = dccp_hdr_reset(skb); | |
401 | dhr->dccph_reset_code = dcb->dccpd_reset_code; | |
402 | ||
403 | switch (dcb->dccpd_reset_code) { | |
404 | case DCCP_RESET_CODE_PACKET_ERROR: | |
405 | dhr->dccph_reset_data[0] = rxdh->dccph_type; | |
406 | break; | |
407 | case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */ | |
408 | case DCCP_RESET_CODE_MANDATORY_ERROR: | |
409 | memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); | |
410 | break; | |
411 | } | |
412 | /* | |
413 | * From RFC 4340, 8.3.1: | |
414 | * If P.ackno exists, set R.seqno := P.ackno + 1. | |
415 | * Else set R.seqno := 0. | |
416 | */ | |
417 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
418 | dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); | |
419 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); | |
420 | ||
421 | dccp_csum_outgoing(skb); | |
422 | return skb; | |
423 | } | |
424 | ||
425 | EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); | |
426 | ||
ee1a1592 | 427 | /* send Reset on established socket, to close or abort the connection */ |
017487d7 ACM |
428 | int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
429 | { | |
ee1a1592 | 430 | struct sk_buff *skb; |
017487d7 ACM |
431 | /* |
432 | * FIXME: what if rebuild_header fails? | |
433 | * Should we be doing a rebuild_header here? | |
434 | */ | |
f53dc67c | 435 | int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
017487d7 | 436 | |
ee1a1592 GR |
437 | if (err != 0) |
438 | return err; | |
439 | ||
440 | skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); | |
441 | if (skb == NULL) | |
442 | return -ENOBUFS; | |
443 | ||
444 | /* Reserve space for headers and prepare control bits. */ | |
445 | skb_reserve(skb, sk->sk_prot->max_header); | |
446 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
447 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
017487d7 | 448 | |
ee1a1592 | 449 | return dccp_transmit_skb(sk, skb); |
017487d7 ACM |
450 | } |
451 | ||
7c657876 ACM |
452 | /* |
453 | * Do all connect socket setups that can be done AF independent. | |
454 | */ | |
455 | static inline void dccp_connect_init(struct sock *sk) | |
456 | { | |
f21e68ca | 457 | struct dccp_sock *dp = dccp_sk(sk); |
7c657876 ACM |
458 | struct dst_entry *dst = __sk_dst_get(sk); |
459 | struct inet_connection_sock *icsk = inet_csk(sk); | |
460 | ||
461 | sk->sk_err = 0; | |
462 | sock_reset_flag(sk, SOCK_DONE); | |
c9eaf173 | 463 | |
7c657876 ACM |
464 | dccp_sync_mss(sk, dst_mtu(dst)); |
465 | ||
73f18fdb | 466 | /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ |
d7f7365f GR |
467 | dp->dccps_gar = dp->dccps_iss; |
468 | ||
7c657876 ACM |
469 | icsk->icsk_retransmits = 0; |
470 | } | |
471 | ||
472 | int dccp_connect(struct sock *sk) | |
473 | { | |
474 | struct sk_buff *skb; | |
475 | struct inet_connection_sock *icsk = inet_csk(sk); | |
476 | ||
9eca0a47 GR |
477 | /* do not connect if feature negotiation setup fails */ |
478 | if (dccp_feat_finalise_settings(dccp_sk(sk))) | |
479 | return -EPROTO; | |
480 | ||
7c657876 ACM |
481 | dccp_connect_init(sk); |
482 | ||
118b2c95 | 483 | skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
7c657876 ACM |
484 | if (unlikely(skb == NULL)) |
485 | return -ENOBUFS; | |
486 | ||
487 | /* Reserve space for headers. */ | |
118b2c95 | 488 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
489 | |
490 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 | 491 | |
48918a4d | 492 | dccp_skb_entail(sk, skb); |
7c657876 ACM |
493 | dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); |
494 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); | |
495 | ||
496 | /* Timer for repeating the REQUEST until an answer. */ | |
27258ee5 ACM |
497 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
498 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
499 | return 0; |
500 | } | |
501 | ||
f21e68ca ACM |
502 | EXPORT_SYMBOL_GPL(dccp_connect); |
503 | ||
7c657876 ACM |
504 | void dccp_send_ack(struct sock *sk) |
505 | { | |
506 | /* If we have been reset, we may not send again. */ | |
507 | if (sk->sk_state != DCCP_CLOSED) { | |
118b2c95 ACM |
508 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
509 | GFP_ATOMIC); | |
7c657876 ACM |
510 | |
511 | if (skb == NULL) { | |
512 | inet_csk_schedule_ack(sk); | |
513 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
514 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
515 | TCP_DELACK_MAX, | |
516 | DCCP_RTO_MAX); | |
7c657876 ACM |
517 | return; |
518 | } | |
519 | ||
520 | /* Reserve space for headers */ | |
118b2c95 | 521 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 522 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
7c657876 ACM |
523 | dccp_transmit_skb(sk, skb); |
524 | } | |
525 | } | |
526 | ||
527 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
528 | ||
1e2f0e5e | 529 | #if 0 |
727ecc5f | 530 | /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
7c657876 ACM |
531 | void dccp_send_delayed_ack(struct sock *sk) |
532 | { | |
533 | struct inet_connection_sock *icsk = inet_csk(sk); | |
534 | /* | |
535 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
536 | * with using 2s, and active senders also piggyback the ACK into a | |
537 | * DATAACK packet, so this is really for quiescent senders. | |
538 | */ | |
539 | unsigned long timeout = jiffies + 2 * HZ; | |
540 | ||
541 | /* Use new timeout only if there wasn't a older one earlier. */ | |
542 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
543 | /* If delack timer was blocked or is about to expire, | |
544 | * send ACK now. | |
545 | * | |
546 | * FIXME: check the "about to expire" part | |
547 | */ | |
548 | if (icsk->icsk_ack.blocked) { | |
549 | dccp_send_ack(sk); | |
550 | return; | |
551 | } | |
552 | ||
553 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
554 | timeout = icsk->icsk_ack.timeout; | |
555 | } | |
556 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
557 | icsk->icsk_ack.timeout = timeout; | |
558 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
559 | } | |
1e2f0e5e | 560 | #endif |
7c657876 | 561 | |
b0d045ca | 562 | void dccp_send_sync(struct sock *sk, const u64 ackno, |
e92ae93a | 563 | const enum dccp_pkt_type pkt_type) |
7c657876 ACM |
564 | { |
565 | /* | |
566 | * We are not putting this on the write queue, so | |
567 | * dccp_transmit_skb() will set the ownership to this | |
568 | * sock. | |
569 | */ | |
118b2c95 | 570 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
7c657876 | 571 | |
b0d045ca | 572 | if (skb == NULL) { |
7c657876 | 573 | /* FIXME: how to make sure the sync is sent? */ |
b0d045ca | 574 | DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
7c657876 | 575 | return; |
b0d045ca | 576 | } |
7c657876 ACM |
577 | |
578 | /* Reserve space for headers and prepare control bits. */ | |
118b2c95 | 579 | skb_reserve(skb, sk->sk_prot->max_header); |
e92ae93a | 580 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
b0d045ca | 581 | DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
7c657876 | 582 | |
7c657876 ACM |
583 | dccp_transmit_skb(sk, skb); |
584 | } | |
585 | ||
b61fafc4 ACM |
586 | EXPORT_SYMBOL_GPL(dccp_send_sync); |
587 | ||
7690af3f ACM |
588 | /* |
589 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
590 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
591 | * any circumstances. | |
7c657876 | 592 | */ |
7ad07e7c | 593 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
594 | { |
595 | struct dccp_sock *dp = dccp_sk(sk); | |
596 | struct sk_buff *skb; | |
7d877f3b | 597 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 598 | |
7ad07e7c ACM |
599 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
600 | if (skb == NULL) | |
601 | return; | |
7c657876 ACM |
602 | |
603 | /* Reserve space for headers and prepare control bits. */ | |
604 | skb_reserve(skb, sk->sk_prot->max_header); | |
b8599d20 GR |
605 | if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
606 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; | |
607 | else | |
608 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; | |
7c657876 | 609 | |
7ad07e7c | 610 | if (active) { |
97e5848d | 611 | dccp_write_xmit(sk, 1); |
48918a4d | 612 | dccp_skb_entail(sk, skb); |
7ad07e7c | 613 | dccp_transmit_skb(sk, skb_clone(skb, prio)); |
92d31920 GR |
614 | /* |
615 | * Retransmission timer for active-close: RFC 4340, 8.3 requires | |
616 | * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ | |
617 | * state can be left. The initial timeout is 2 RTTs. | |
618 | * Since RTT measurement is done by the CCIDs, there is no easy | |
619 | * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 | |
620 | * is too low (200ms); we use a high value to avoid unnecessary | |
621 | * retransmissions when the link RTT is > 0.2 seconds. | |
622 | * FIXME: Let main module sample RTTs and use that instead. | |
623 | */ | |
624 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
625 | DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); | |
7ad07e7c ACM |
626 | } else |
627 | dccp_transmit_skb(sk, skb); | |
7c657876 | 628 | } |