Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/output.c | |
3 | * | |
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 | ||
13 | #include <linux/config.h> | |
14 | #include <linux/dccp.h> | |
15 | #include <linux/skbuff.h> | |
16 | ||
17 | #include <net/sock.h> | |
18 | ||
ae31c339 | 19 | #include "ackvec.h" |
7c657876 ACM |
20 | #include "ccid.h" |
21 | #include "dccp.h" | |
22 | ||
23 | static inline void dccp_event_ack_sent(struct sock *sk) | |
24 | { | |
25 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
26 | } | |
27 | ||
28 | /* | |
29 | * All SKB's seen here are completely headerless. It is our | |
30 | * job to build the DCCP header, and pass the packet down to | |
31 | * IP so it can do the same plus pass the packet off to the | |
32 | * device. | |
33 | */ | |
34 | int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) | |
35 | { | |
36 | if (likely(skb != NULL)) { | |
37 | const struct inet_sock *inet = inet_sk(sk); | |
38 | struct dccp_sock *dp = dccp_sk(sk); | |
39 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
40 | struct dccp_hdr *dh; | |
41 | /* XXX For now we're using only 48 bits sequence numbers */ | |
42 | const int dccp_header_size = sizeof(*dh) + | |
43 | sizeof(struct dccp_hdr_ext) + | |
7690af3f | 44 | dccp_packet_hdr_len(dcb->dccpd_type); |
7c657876 ACM |
45 | int err, set_ack = 1; |
46 | u64 ackno = dp->dccps_gsr; | |
47 | ||
7c657876 ACM |
48 | dccp_inc_seqno(&dp->dccps_gss); |
49 | ||
7c657876 ACM |
50 | switch (dcb->dccpd_type) { |
51 | case DCCP_PKT_DATA: | |
52 | set_ack = 0; | |
53 | break; | |
54 | case DCCP_PKT_SYNC: | |
55 | case DCCP_PKT_SYNCACK: | |
56 | ackno = dcb->dccpd_seq; | |
57 | break; | |
58 | } | |
24117727 ACM |
59 | |
60 | dcb->dccpd_seq = dp->dccps_gss; | |
61 | dccp_insert_options(sk, skb); | |
7c657876 ACM |
62 | |
63 | skb->h.raw = skb_push(skb, dccp_header_size); | |
64 | dh = dccp_hdr(skb); | |
fda0fd6c HX |
65 | |
66 | if (!skb->sk) | |
7c657876 ACM |
67 | skb_set_owner_w(skb, sk); |
68 | ||
69 | /* Build DCCP header and checksum it. */ | |
70 | memset(dh, 0, dccp_header_size); | |
71 | dh->dccph_type = dcb->dccpd_type; | |
72 | dh->dccph_sport = inet->sport; | |
73 | dh->dccph_dport = inet->dport; | |
74 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; | |
75 | dh->dccph_ccval = dcb->dccpd_ccval; | |
76 | /* XXX For now we're using only 48 bits sequence numbers */ | |
77 | dh->dccph_x = 1; | |
78 | ||
79 | dp->dccps_awh = dp->dccps_gss; | |
80 | dccp_hdr_set_seq(dh, dp->dccps_gss); | |
81 | if (set_ack) | |
82 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
83 | ||
84 | switch (dcb->dccpd_type) { | |
85 | case DCCP_PKT_REQUEST: | |
7690af3f | 86 | dccp_hdr_request(skb)->dccph_req_service = |
67e6b629 | 87 | dp->dccps_service; |
7c657876 ACM |
88 | break; |
89 | case DCCP_PKT_RESET: | |
7690af3f ACM |
90 | dccp_hdr_reset(skb)->dccph_reset_code = |
91 | dcb->dccpd_reset_code; | |
7c657876 ACM |
92 | break; |
93 | } | |
94 | ||
95b81ef7 YN |
95 | dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, |
96 | inet->daddr); | |
7c657876 | 97 | |
7ad07e7c | 98 | if (set_ack) |
7c657876 ACM |
99 | dccp_event_ack_sent(sk); |
100 | ||
101 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
102 | ||
49c5bfaf | 103 | memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); |
7c657876 ACM |
104 | err = ip_queue_xmit(skb, 0); |
105 | if (err <= 0) | |
106 | return err; | |
107 | ||
108 | /* NET_XMIT_CN is special. It does not guarantee, | |
109 | * that this packet is lost. It tells that device | |
110 | * is about to start to drop packets or already | |
111 | * drops some packets of the same priority and | |
112 | * invokes us to send less aggressively. | |
113 | */ | |
114 | return err == NET_XMIT_CN ? 0 : err; | |
115 | } | |
116 | return -ENOBUFS; | |
117 | } | |
118 | ||
119 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) | |
120 | { | |
121 | struct dccp_sock *dp = dccp_sk(sk); | |
122 | int mss_now; | |
123 | ||
124 | /* | |
7690af3f ACM |
125 | * FIXME: we really should be using the af_specific thing to support |
126 | * IPv6. | |
127 | * mss_now = pmtu - tp->af_specific->net_header_len - | |
128 | * sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext); | |
7c657876 | 129 | */ |
7690af3f ACM |
130 | mss_now = pmtu - sizeof(struct iphdr) - sizeof(struct dccp_hdr) - |
131 | sizeof(struct dccp_hdr_ext); | |
7c657876 ACM |
132 | |
133 | /* Now subtract optional transport overhead */ | |
134 | mss_now -= dp->dccps_ext_header_len; | |
135 | ||
136 | /* | |
137 | * FIXME: this should come from the CCID infrastructure, where, say, | |
138 | * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets | |
139 | * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED | |
140 | * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to | |
141 | * make it a multiple of 4 | |
142 | */ | |
143 | ||
144 | mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4; | |
145 | ||
146 | /* And store cached results */ | |
147 | dp->dccps_pmtu_cookie = pmtu; | |
148 | dp->dccps_mss_cache = mss_now; | |
149 | ||
150 | return mss_now; | |
151 | } | |
152 | ||
c530cfb1 ACM |
153 | void dccp_write_space(struct sock *sk) |
154 | { | |
155 | read_lock(&sk->sk_callback_lock); | |
156 | ||
157 | if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) | |
158 | wake_up_interruptible(sk->sk_sleep); | |
159 | /* Should agree with poll, otherwise some programs break */ | |
160 | if (sock_writeable(sk)) | |
161 | sk_wake_async(sk, 2, POLL_OUT); | |
162 | ||
163 | read_unlock(&sk->sk_callback_lock); | |
164 | } | |
165 | ||
d6809c12 ACM |
166 | /** |
167 | * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet | |
168 | * @sk: socket to wait for | |
169 | * @timeo: for how long | |
170 | */ | |
171 | static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, | |
172 | long *timeo) | |
173 | { | |
174 | struct dccp_sock *dp = dccp_sk(sk); | |
175 | DEFINE_WAIT(wait); | |
176 | long delay; | |
177 | int rc; | |
178 | ||
179 | while (1) { | |
180 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); | |
181 | ||
182 | if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) | |
183 | goto do_error; | |
184 | if (!*timeo) | |
185 | goto do_nonblock; | |
186 | if (signal_pending(current)) | |
187 | goto do_interrupted; | |
188 | ||
189 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb, | |
190 | skb->len); | |
191 | if (rc <= 0) | |
192 | break; | |
193 | delay = msecs_to_jiffies(rc); | |
194 | if (delay > *timeo || delay < 0) | |
195 | goto do_nonblock; | |
196 | ||
197 | sk->sk_write_pending++; | |
198 | release_sock(sk); | |
199 | *timeo -= schedule_timeout(delay); | |
200 | lock_sock(sk); | |
201 | sk->sk_write_pending--; | |
202 | } | |
203 | out: | |
204 | finish_wait(sk->sk_sleep, &wait); | |
205 | return rc; | |
206 | ||
207 | do_error: | |
208 | rc = -EPIPE; | |
209 | goto out; | |
210 | do_nonblock: | |
211 | rc = -EAGAIN; | |
212 | goto out; | |
213 | do_interrupted: | |
214 | rc = sock_intr_errno(*timeo); | |
215 | goto out; | |
216 | } | |
217 | ||
218 | int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo) | |
27258ee5 ACM |
219 | { |
220 | const struct dccp_sock *dp = dccp_sk(sk); | |
d6809c12 ACM |
221 | int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb, |
222 | skb->len); | |
223 | ||
224 | if (err > 0) | |
225 | err = dccp_wait_for_ccid(sk, skb, timeo); | |
27258ee5 ACM |
226 | |
227 | if (err == 0) { | |
27258ee5 | 228 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
d6809c12 | 229 | const int len = skb->len; |
27258ee5 ACM |
230 | |
231 | if (sk->sk_state == DCCP_PARTOPEN) { | |
232 | /* See 8.1.5. Handshake Completion */ | |
233 | inet_csk_schedule_ack(sk); | |
234 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
235 | inet_csk(sk)->icsk_rto, | |
236 | DCCP_RTO_MAX); | |
237 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
ae31c339 | 238 | } else if (dccp_ack_pending(sk)) |
27258ee5 ACM |
239 | dcb->dccpd_type = DCCP_PKT_DATAACK; |
240 | else | |
241 | dcb->dccpd_type = DCCP_PKT_DATA; | |
242 | ||
243 | err = dccp_transmit_skb(sk, skb); | |
244 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); | |
ffa29347 HX |
245 | } else |
246 | kfree_skb(skb); | |
27258ee5 ACM |
247 | |
248 | return err; | |
249 | } | |
250 | ||
7c657876 ACM |
251 | int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb) |
252 | { | |
253 | if (inet_sk_rebuild_header(sk) != 0) | |
254 | return -EHOSTUNREACH; /* Routing failure or similar. */ | |
255 | ||
256 | return dccp_transmit_skb(sk, (skb_cloned(skb) ? | |
257 | pskb_copy(skb, GFP_ATOMIC): | |
258 | skb_clone(skb, GFP_ATOMIC))); | |
259 | } | |
260 | ||
261 | struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, | |
262 | struct request_sock *req) | |
263 | { | |
264 | struct dccp_hdr *dh; | |
67e6b629 | 265 | struct dccp_request_sock *dreq; |
7c657876 ACM |
266 | const int dccp_header_size = sizeof(struct dccp_hdr) + |
267 | sizeof(struct dccp_hdr_ext) + | |
268 | sizeof(struct dccp_hdr_response); | |
269 | struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN + | |
270 | dccp_header_size, 1, | |
271 | GFP_ATOMIC); | |
272 | if (skb == NULL) | |
273 | return NULL; | |
274 | ||
275 | /* Reserve space for headers. */ | |
276 | skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size); | |
277 | ||
278 | skb->dst = dst_clone(dst); | |
279 | skb->csum = 0; | |
280 | ||
67e6b629 | 281 | dreq = dccp_rsk(req); |
7c657876 | 282 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
67e6b629 | 283 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; |
7c657876 ACM |
284 | dccp_insert_options(sk, skb); |
285 | ||
286 | skb->h.raw = skb_push(skb, dccp_header_size); | |
287 | ||
288 | dh = dccp_hdr(skb); | |
289 | memset(dh, 0, dccp_header_size); | |
290 | ||
291 | dh->dccph_sport = inet_sk(sk)->sport; | |
292 | dh->dccph_dport = inet_rsk(req)->rmt_port; | |
7690af3f ACM |
293 | dh->dccph_doff = (dccp_header_size + |
294 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
295 | dh->dccph_type = DCCP_PKT_RESPONSE; |
296 | dh->dccph_x = 1; | |
67e6b629 ACM |
297 | dccp_hdr_set_seq(dh, dreq->dreq_iss); |
298 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr); | |
299 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; | |
7c657876 | 300 | |
95b81ef7 YN |
301 | dh->dccph_checksum = dccp_v4_checksum(skb, inet_rsk(req)->loc_addr, |
302 | inet_rsk(req)->rmt_addr); | |
7c657876 ACM |
303 | |
304 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
305 | return skb; | |
306 | } | |
307 | ||
308 | struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst, | |
309 | const enum dccp_reset_codes code) | |
310 | ||
311 | { | |
312 | struct dccp_hdr *dh; | |
313 | struct dccp_sock *dp = dccp_sk(sk); | |
314 | const int dccp_header_size = sizeof(struct dccp_hdr) + | |
315 | sizeof(struct dccp_hdr_ext) + | |
316 | sizeof(struct dccp_hdr_reset); | |
317 | struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN + | |
318 | dccp_header_size, 1, | |
319 | GFP_ATOMIC); | |
320 | if (skb == NULL) | |
321 | return NULL; | |
322 | ||
323 | /* Reserve space for headers. */ | |
324 | skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size); | |
325 | ||
326 | skb->dst = dst_clone(dst); | |
327 | skb->csum = 0; | |
328 | ||
329 | dccp_inc_seqno(&dp->dccps_gss); | |
330 | ||
331 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
332 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
333 | DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss; | |
334 | dccp_insert_options(sk, skb); | |
335 | ||
336 | skb->h.raw = skb_push(skb, dccp_header_size); | |
337 | ||
338 | dh = dccp_hdr(skb); | |
339 | memset(dh, 0, dccp_header_size); | |
340 | ||
341 | dh->dccph_sport = inet_sk(sk)->sport; | |
342 | dh->dccph_dport = inet_sk(sk)->dport; | |
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_RESET; |
346 | dh->dccph_x = 1; | |
347 | dccp_hdr_set_seq(dh, dp->dccps_gss); | |
348 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr); | |
349 | ||
350 | dccp_hdr_reset(skb)->dccph_reset_code = code; | |
351 | ||
95b81ef7 YN |
352 | dh->dccph_checksum = dccp_v4_checksum(skb, inet_sk(sk)->saddr, |
353 | inet_sk(sk)->daddr); | |
7c657876 ACM |
354 | |
355 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
356 | return skb; | |
357 | } | |
358 | ||
359 | /* | |
360 | * Do all connect socket setups that can be done AF independent. | |
361 | */ | |
362 | static inline void dccp_connect_init(struct sock *sk) | |
363 | { | |
364 | struct dst_entry *dst = __sk_dst_get(sk); | |
365 | struct inet_connection_sock *icsk = inet_csk(sk); | |
366 | ||
367 | sk->sk_err = 0; | |
368 | sock_reset_flag(sk, SOCK_DONE); | |
369 | ||
370 | dccp_sync_mss(sk, dst_mtu(dst)); | |
371 | ||
372 | /* | |
373 | * FIXME: set dp->{dccps_swh,dccps_swl}, with | |
374 | * something like dccp_inc_seq | |
375 | */ | |
376 | ||
377 | icsk->icsk_retransmits = 0; | |
378 | } | |
379 | ||
380 | int dccp_connect(struct sock *sk) | |
381 | { | |
382 | struct sk_buff *skb; | |
383 | struct inet_connection_sock *icsk = inet_csk(sk); | |
384 | ||
385 | dccp_connect_init(sk); | |
386 | ||
387 | skb = alloc_skb(MAX_DCCP_HEADER + 15, sk->sk_allocation); | |
388 | if (unlikely(skb == NULL)) | |
389 | return -ENOBUFS; | |
390 | ||
391 | /* Reserve space for headers. */ | |
392 | skb_reserve(skb, MAX_DCCP_HEADER); | |
393 | ||
394 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 ACM |
395 | skb->csum = 0; |
396 | skb_set_owner_w(skb, sk); | |
397 | ||
398 | BUG_TRAP(sk->sk_send_head == NULL); | |
399 | sk->sk_send_head = skb; | |
400 | dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); | |
401 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); | |
402 | ||
403 | /* Timer for repeating the REQUEST until an answer. */ | |
27258ee5 ACM |
404 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
405 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
406 | return 0; |
407 | } | |
408 | ||
409 | void dccp_send_ack(struct sock *sk) | |
410 | { | |
411 | /* If we have been reset, we may not send again. */ | |
412 | if (sk->sk_state != DCCP_CLOSED) { | |
413 | struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC); | |
414 | ||
415 | if (skb == NULL) { | |
416 | inet_csk_schedule_ack(sk); | |
417 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
418 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
419 | TCP_DELACK_MAX, | |
420 | DCCP_RTO_MAX); | |
7c657876 ACM |
421 | return; |
422 | } | |
423 | ||
424 | /* Reserve space for headers */ | |
425 | skb_reserve(skb, MAX_DCCP_HEADER); | |
426 | skb->csum = 0; | |
427 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; | |
428 | skb_set_owner_w(skb, sk); | |
429 | dccp_transmit_skb(sk, skb); | |
430 | } | |
431 | } | |
432 | ||
433 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
434 | ||
435 | void dccp_send_delayed_ack(struct sock *sk) | |
436 | { | |
437 | struct inet_connection_sock *icsk = inet_csk(sk); | |
438 | /* | |
439 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
440 | * with using 2s, and active senders also piggyback the ACK into a | |
441 | * DATAACK packet, so this is really for quiescent senders. | |
442 | */ | |
443 | unsigned long timeout = jiffies + 2 * HZ; | |
444 | ||
445 | /* Use new timeout only if there wasn't a older one earlier. */ | |
446 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
447 | /* If delack timer was blocked or is about to expire, | |
448 | * send ACK now. | |
449 | * | |
450 | * FIXME: check the "about to expire" part | |
451 | */ | |
452 | if (icsk->icsk_ack.blocked) { | |
453 | dccp_send_ack(sk); | |
454 | return; | |
455 | } | |
456 | ||
457 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
458 | timeout = icsk->icsk_ack.timeout; | |
459 | } | |
460 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
461 | icsk->icsk_ack.timeout = timeout; | |
462 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
463 | } | |
464 | ||
e92ae93a ACM |
465 | void dccp_send_sync(struct sock *sk, const u64 seq, |
466 | const enum dccp_pkt_type pkt_type) | |
7c657876 ACM |
467 | { |
468 | /* | |
469 | * We are not putting this on the write queue, so | |
470 | * dccp_transmit_skb() will set the ownership to this | |
471 | * sock. | |
472 | */ | |
473 | struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC); | |
474 | ||
475 | if (skb == NULL) | |
476 | /* FIXME: how to make sure the sync is sent? */ | |
477 | return; | |
478 | ||
479 | /* Reserve space for headers and prepare control bits. */ | |
480 | skb_reserve(skb, MAX_DCCP_HEADER); | |
481 | skb->csum = 0; | |
e92ae93a | 482 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
7c657876 ACM |
483 | DCCP_SKB_CB(skb)->dccpd_seq = seq; |
484 | ||
485 | skb_set_owner_w(skb, sk); | |
486 | dccp_transmit_skb(sk, skb); | |
487 | } | |
488 | ||
7690af3f ACM |
489 | /* |
490 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
491 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
492 | * any circumstances. | |
7c657876 | 493 | */ |
7ad07e7c | 494 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
495 | { |
496 | struct dccp_sock *dp = dccp_sk(sk); | |
497 | struct sk_buff *skb; | |
7d877f3b | 498 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 499 | |
7ad07e7c ACM |
500 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
501 | if (skb == NULL) | |
502 | return; | |
7c657876 ACM |
503 | |
504 | /* Reserve space for headers and prepare control bits. */ | |
505 | skb_reserve(skb, sk->sk_prot->max_header); | |
506 | skb->csum = 0; | |
7690af3f ACM |
507 | DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ? |
508 | DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ; | |
7c657876 ACM |
509 | |
510 | skb_set_owner_w(skb, sk); | |
7ad07e7c ACM |
511 | if (active) { |
512 | BUG_TRAP(sk->sk_send_head == NULL); | |
513 | sk->sk_send_head = skb; | |
514 | dccp_transmit_skb(sk, skb_clone(skb, prio)); | |
515 | } else | |
516 | dccp_transmit_skb(sk, skb); | |
7c657876 | 517 | } |