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 | 15 | #include <linux/skbuff.h> |
5a0e3ad6 | 16 | #include <linux/slab.h> |
174cd4b1 | 17 | #include <linux/sched/signal.h> |
7c657876 | 18 | |
14c85021 | 19 | #include <net/inet_sock.h> |
7c657876 ACM |
20 | #include <net/sock.h> |
21 | ||
ae31c339 | 22 | #include "ackvec.h" |
7c657876 ACM |
23 | #include "ccid.h" |
24 | #include "dccp.h" | |
25 | ||
26 | static inline void dccp_event_ack_sent(struct sock *sk) | |
27 | { | |
28 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
29 | } | |
30 | ||
8695e801 GR |
31 | /* enqueue @skb on sk_send_head for retransmission, return clone to send now */ |
32 | static struct sk_buff *dccp_skb_entail(struct sock *sk, struct sk_buff *skb) | |
48918a4d HX |
33 | { |
34 | skb_set_owner_w(skb, sk); | |
35 | WARN_ON(sk->sk_send_head); | |
36 | sk->sk_send_head = skb; | |
8695e801 | 37 | return skb_clone(sk->sk_send_head, gfp_any()); |
48918a4d HX |
38 | } |
39 | ||
7c657876 ACM |
40 | /* |
41 | * All SKB's seen here are completely headerless. It is our | |
42 | * job to build the DCCP header, and pass the packet down to | |
43 | * IP so it can do the same plus pass the packet off to the | |
44 | * device. | |
45 | */ | |
48918a4d | 46 | static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
47 | { |
48 | if (likely(skb != NULL)) { | |
d9d8da80 | 49 | struct inet_sock *inet = inet_sk(sk); |
57cca05a | 50 | const struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 ACM |
51 | struct dccp_sock *dp = dccp_sk(sk); |
52 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
53 | struct dccp_hdr *dh; | |
54 | /* XXX For now we're using only 48 bits sequence numbers */ | |
118b2c95 | 55 | const u32 dccp_header_size = sizeof(*dh) + |
7c657876 | 56 | sizeof(struct dccp_hdr_ext) + |
7690af3f | 57 | dccp_packet_hdr_len(dcb->dccpd_type); |
7c657876 ACM |
58 | int err, set_ack = 1; |
59 | u64 ackno = dp->dccps_gsr; | |
73f18fdb GR |
60 | /* |
61 | * Increment GSS here already in case the option code needs it. | |
62 | * Update GSS for real only if option processing below succeeds. | |
63 | */ | |
64 | dcb->dccpd_seq = ADD48(dp->dccps_gss, 1); | |
7c657876 | 65 | |
7c657876 ACM |
66 | switch (dcb->dccpd_type) { |
67 | case DCCP_PKT_DATA: | |
68 | set_ack = 0; | |
edc9e819 HX |
69 | /* fall through */ |
70 | case DCCP_PKT_DATAACK: | |
ee1a1592 | 71 | case DCCP_PKT_RESET: |
7c657876 | 72 | break; |
edc9e819 | 73 | |
afe00251 AB |
74 | case DCCP_PKT_REQUEST: |
75 | set_ack = 0; | |
73f18fdb GR |
76 | /* Use ISS on the first (non-retransmitted) Request. */ |
77 | if (icsk->icsk_retransmits == 0) | |
78 | dcb->dccpd_seq = dp->dccps_iss; | |
afe00251 AB |
79 | /* fall through */ |
80 | ||
7c657876 ACM |
81 | case DCCP_PKT_SYNC: |
82 | case DCCP_PKT_SYNCACK: | |
b0d045ca | 83 | ackno = dcb->dccpd_ack_seq; |
edc9e819 HX |
84 | /* fall through */ |
85 | default: | |
86 | /* | |
ee1a1592 GR |
87 | * Set owner/destructor: some skbs are allocated via |
88 | * alloc_skb (e.g. when retransmission may happen). | |
89 | * Only Data, DataAck, and Reset packets should come | |
90 | * through here with skb->sk set. | |
edc9e819 HX |
91 | */ |
92 | WARN_ON(skb->sk); | |
93 | skb_set_owner_w(skb, sk); | |
7c657876 ACM |
94 | break; |
95 | } | |
24117727 | 96 | |
2d0817d1 ACM |
97 | if (dccp_insert_options(sk, skb)) { |
98 | kfree_skb(skb); | |
99 | return -EPROTO; | |
100 | } | |
c9eaf173 | 101 | |
fda0fd6c | 102 | |
7c657876 | 103 | /* Build DCCP header and checksum it. */ |
9b42078e | 104 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 105 | dh->dccph_type = dcb->dccpd_type; |
c720c7e8 ED |
106 | dh->dccph_sport = inet->inet_sport; |
107 | dh->dccph_dport = inet->inet_dport; | |
7c657876 ACM |
108 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; |
109 | dh->dccph_ccval = dcb->dccpd_ccval; | |
6f4e5fff | 110 | dh->dccph_cscov = dp->dccps_pcslen; |
7c657876 ACM |
111 | /* XXX For now we're using only 48 bits sequence numbers */ |
112 | dh->dccph_x = 1; | |
113 | ||
73f18fdb | 114 | dccp_update_gss(sk, dcb->dccpd_seq); |
7c657876 ACM |
115 | dccp_hdr_set_seq(dh, dp->dccps_gss); |
116 | if (set_ack) | |
117 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
118 | ||
119 | switch (dcb->dccpd_type) { | |
120 | case DCCP_PKT_REQUEST: | |
7690af3f | 121 | dccp_hdr_request(skb)->dccph_req_service = |
67e6b629 | 122 | dp->dccps_service; |
73f18fdb GR |
123 | /* |
124 | * Limit Ack window to ISS <= P.ackno <= GSS, so that | |
125 | * only Responses to Requests we sent are considered. | |
126 | */ | |
127 | dp->dccps_awl = dp->dccps_iss; | |
7c657876 ACM |
128 | break; |
129 | case DCCP_PKT_RESET: | |
7690af3f ACM |
130 | dccp_hdr_reset(skb)->dccph_reset_code = |
131 | dcb->dccpd_reset_code; | |
7c657876 ACM |
132 | break; |
133 | } | |
134 | ||
bb296246 | 135 | icsk->icsk_af_ops->send_check(sk, skb); |
7c657876 | 136 | |
7ad07e7c | 137 | if (set_ack) |
7c657876 ACM |
138 | dccp_event_ack_sent(sk); |
139 | ||
140 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
141 | ||
b0270e91 | 142 | err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl); |
b9df3cb8 | 143 | return net_xmit_eval(err); |
7c657876 ACM |
144 | } |
145 | return -ENOBUFS; | |
146 | } | |
147 | ||
6179983a | 148 | /** |
25985edc | 149 | * dccp_determine_ccmps - Find out about CCID-specific packet-size limits |
6179983a GR |
150 | * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), |
151 | * since the RX CCID is restricted to feedback packets (Acks), which are small | |
152 | * in comparison with the data traffic. A value of 0 means "no current CCMPS". | |
153 | */ | |
154 | static u32 dccp_determine_ccmps(const struct dccp_sock *dp) | |
155 | { | |
156 | const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; | |
157 | ||
158 | if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) | |
159 | return 0; | |
160 | return tx_ccid->ccid_ops->ccid_ccmps; | |
161 | } | |
162 | ||
7c657876 ACM |
163 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
164 | { | |
d83d8461 | 165 | struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 | 166 | struct dccp_sock *dp = dccp_sk(sk); |
6179983a | 167 | u32 ccmps = dccp_determine_ccmps(dp); |
361a5c1d | 168 | u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; |
7c657876 | 169 | |
6179983a GR |
170 | /* Account for header lengths and IPv4/v6 option overhead */ |
171 | cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + | |
172 | sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); | |
7c657876 ACM |
173 | |
174 | /* | |
361a5c1d GR |
175 | * Leave enough headroom for common DCCP header options. |
176 | * This only considers options which may appear on DCCP-Data packets, as | |
177 | * per table 3 in RFC 4340, 5.8. When running out of space for other | |
178 | * options (eg. Ack Vector which can take up to 255 bytes), it is better | |
179 | * to schedule a separate Ack. Thus we leave headroom for the following: | |
180 | * - 1 byte for Slow Receiver (11.6) | |
181 | * - 6 bytes for Timestamp (13.1) | |
182 | * - 10 bytes for Timestamp Echo (13.3) | |
183 | * - 8 bytes for NDP count (7.7, when activated) | |
184 | * - 6 bytes for Data Checksum (9.3) | |
185 | * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled) | |
7c657876 | 186 | */ |
361a5c1d GR |
187 | cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 + |
188 | (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4); | |
7c657876 ACM |
189 | |
190 | /* And store cached results */ | |
d83d8461 | 191 | icsk->icsk_pmtu_cookie = pmtu; |
6179983a | 192 | dp->dccps_mss_cache = cur_mps; |
7c657876 | 193 | |
6179983a | 194 | return cur_mps; |
7c657876 ACM |
195 | } |
196 | ||
f21e68ca ACM |
197 | EXPORT_SYMBOL_GPL(dccp_sync_mss); |
198 | ||
c530cfb1 ACM |
199 | void dccp_write_space(struct sock *sk) |
200 | { | |
43815482 | 201 | struct socket_wq *wq; |
c530cfb1 | 202 | |
43815482 ED |
203 | rcu_read_lock(); |
204 | wq = rcu_dereference(sk->sk_wq); | |
1ce0bf50 | 205 | if (skwq_has_sleeper(wq)) |
43815482 | 206 | wake_up_interruptible(&wq->wait); |
c530cfb1 ACM |
207 | /* Should agree with poll, otherwise some programs break */ |
208 | if (sock_writeable(sk)) | |
8d8ad9d7 | 209 | sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
c530cfb1 | 210 | |
43815482 | 211 | rcu_read_unlock(); |
c530cfb1 ACM |
212 | } |
213 | ||
d6809c12 | 214 | /** |
b1fcf55e | 215 | * dccp_wait_for_ccid - Await CCID send permission |
bc849872 | 216 | * @sk: socket to wait for |
b1fcf55e | 217 | * @delay: timeout in jiffies |
2c53040f | 218 | * |
b1fcf55e | 219 | * This is used by CCIDs which need to delay the send time in process context. |
d6809c12 | 220 | */ |
b1fcf55e | 221 | static int dccp_wait_for_ccid(struct sock *sk, unsigned long delay) |
d6809c12 | 222 | { |
d6809c12 | 223 | DEFINE_WAIT(wait); |
b1fcf55e | 224 | long remaining; |
d6809c12 | 225 | |
b1fcf55e GR |
226 | prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); |
227 | sk->sk_write_pending++; | |
228 | release_sock(sk); | |
bc849872 | 229 | |
b1fcf55e | 230 | remaining = schedule_timeout(delay); |
d6809c12 | 231 | |
b1fcf55e GR |
232 | lock_sock(sk); |
233 | sk->sk_write_pending--; | |
aa395145 | 234 | finish_wait(sk_sleep(sk), &wait); |
b1fcf55e GR |
235 | |
236 | if (signal_pending(current) || sk->sk_err) | |
237 | return -1; | |
238 | return remaining; | |
d6809c12 ACM |
239 | } |
240 | ||
dc841e30 GR |
241 | /** |
242 | * dccp_xmit_packet - Send data packet under control of CCID | |
243 | * Transmits next-queued payload and informs CCID to account for the packet. | |
244 | */ | |
245 | static void dccp_xmit_packet(struct sock *sk) | |
246 | { | |
247 | int err, len; | |
248 | struct dccp_sock *dp = dccp_sk(sk); | |
871a2c16 | 249 | struct sk_buff *skb = dccp_qpolicy_pop(sk); |
dc841e30 GR |
250 | |
251 | if (unlikely(skb == NULL)) | |
252 | return; | |
253 | len = skb->len; | |
254 | ||
255 | if (sk->sk_state == DCCP_PARTOPEN) { | |
256 | const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; | |
257 | /* | |
258 | * See 8.1.5 - Handshake Completion. | |
259 | * | |
260 | * For robustness we resend Confirm options until the client has | |
261 | * entered OPEN. During the initial feature negotiation, the MPS | |
262 | * is smaller than usual, reduced by the Change/Confirm options. | |
263 | */ | |
264 | if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { | |
265 | DCCP_WARN("Payload too large (%d) for featneg.\n", len); | |
266 | dccp_send_ack(sk); | |
267 | dccp_feat_list_purge(&dp->dccps_featneg); | |
268 | } | |
269 | ||
270 | inet_csk_schedule_ack(sk); | |
271 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
272 | inet_csk(sk)->icsk_rto, | |
273 | DCCP_RTO_MAX); | |
274 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; | |
275 | } else if (dccp_ack_pending(sk)) { | |
276 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK; | |
277 | } else { | |
278 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATA; | |
279 | } | |
280 | ||
281 | err = dccp_transmit_skb(sk, skb); | |
282 | if (err) | |
283 | dccp_pr_debug("transmit_skb() returned err=%d\n", err); | |
284 | /* | |
285 | * Register this one as sent even if an error occurred. To the remote | |
286 | * end a local packet drop is indistinguishable from network loss, i.e. | |
287 | * any local drop will eventually be reported via receiver feedback. | |
288 | */ | |
289 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, len); | |
d83447f0 GR |
290 | |
291 | /* | |
292 | * If the CCID needs to transfer additional header options out-of-band | |
293 | * (e.g. Ack Vectors or feature-negotiation options), it activates this | |
294 | * flag to schedule a Sync. The Sync will automatically incorporate all | |
295 | * currently pending header options, thus clearing the backlog. | |
296 | */ | |
297 | if (dp->dccps_sync_scheduled) | |
298 | dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC); | |
dc841e30 GR |
299 | } |
300 | ||
b1fcf55e GR |
301 | /** |
302 | * dccp_flush_write_queue - Drain queue at end of connection | |
303 | * Since dccp_sendmsg queues packets without waiting for them to be sent, it may | |
304 | * happen that the TX queue is not empty at the end of a connection. We give the | |
305 | * HC-sender CCID a grace period of up to @time_budget jiffies. If this function | |
306 | * returns with a non-empty write queue, it will be purged later. | |
307 | */ | |
308 | void dccp_flush_write_queue(struct sock *sk, long *time_budget) | |
309 | { | |
310 | struct dccp_sock *dp = dccp_sk(sk); | |
311 | struct sk_buff *skb; | |
312 | long delay, rc; | |
313 | ||
314 | while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) { | |
315 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); | |
316 | ||
317 | switch (ccid_packet_dequeue_eval(rc)) { | |
318 | case CCID_PACKET_WILL_DEQUEUE_LATER: | |
319 | /* | |
320 | * If the CCID determines when to send, the next sending | |
321 | * time is unknown or the CCID may not even send again | |
322 | * (e.g. remote host crashes or lost Ack packets). | |
323 | */ | |
324 | DCCP_WARN("CCID did not manage to send all packets\n"); | |
325 | return; | |
326 | case CCID_PACKET_DELAY: | |
327 | delay = msecs_to_jiffies(rc); | |
328 | if (delay > *time_budget) | |
329 | return; | |
330 | rc = dccp_wait_for_ccid(sk, delay); | |
331 | if (rc < 0) | |
332 | return; | |
333 | *time_budget -= (delay - rc); | |
334 | /* check again if we can send now */ | |
335 | break; | |
336 | case CCID_PACKET_SEND_AT_ONCE: | |
337 | dccp_xmit_packet(sk); | |
338 | break; | |
339 | case CCID_PACKET_ERR: | |
340 | skb_dequeue(&sk->sk_write_queue); | |
341 | kfree_skb(skb); | |
342 | dccp_pr_debug("packet discarded due to err=%ld\n", rc); | |
343 | } | |
344 | } | |
345 | } | |
346 | ||
347 | void dccp_write_xmit(struct sock *sk) | |
27258ee5 | 348 | { |
97e5848d IM |
349 | struct dccp_sock *dp = dccp_sk(sk); |
350 | struct sk_buff *skb; | |
97e5848d | 351 | |
871a2c16 | 352 | while ((skb = dccp_qpolicy_top(sk))) { |
dc841e30 | 353 | int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
d6809c12 | 354 | |
dc841e30 GR |
355 | switch (ccid_packet_dequeue_eval(rc)) { |
356 | case CCID_PACKET_WILL_DEQUEUE_LATER: | |
357 | return; | |
358 | case CCID_PACKET_DELAY: | |
b1fcf55e GR |
359 | sk_reset_timer(sk, &dp->dccps_xmit_timer, |
360 | jiffies + msecs_to_jiffies(rc)); | |
361 | return; | |
dc841e30 GR |
362 | case CCID_PACKET_SEND_AT_ONCE: |
363 | dccp_xmit_packet(sk); | |
364 | break; | |
365 | case CCID_PACKET_ERR: | |
871a2c16 | 366 | dccp_qpolicy_drop(sk, skb); |
dc841e30 | 367 | dccp_pr_debug("packet discarded due to err=%d\n", rc); |
f6282f4d | 368 | } |
97e5848d | 369 | } |
27258ee5 ACM |
370 | } |
371 | ||
59435444 GR |
372 | /** |
373 | * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets | |
374 | * There are only four retransmittable packet types in DCCP: | |
375 | * - Request in client-REQUEST state (sec. 8.1.1), | |
376 | * - CloseReq in server-CLOSEREQ state (sec. 8.3), | |
377 | * - Close in node-CLOSING state (sec. 8.3), | |
378 | * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). | |
379 | * This function expects sk->sk_send_head to contain the original skb. | |
380 | */ | |
381 | int dccp_retransmit_skb(struct sock *sk) | |
7c657876 | 382 | { |
59435444 GR |
383 | WARN_ON(sk->sk_send_head == NULL); |
384 | ||
57cca05a | 385 | if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) |
7c657876 ACM |
386 | return -EHOSTUNREACH; /* Routing failure or similar. */ |
387 | ||
59435444 GR |
388 | /* this count is used to distinguish original and retransmitted skb */ |
389 | inet_csk(sk)->icsk_retransmits++; | |
390 | ||
391 | return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); | |
7c657876 ACM |
392 | } |
393 | ||
802885fc | 394 | struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst, |
7c657876 ACM |
395 | struct request_sock *req) |
396 | { | |
397 | struct dccp_hdr *dh; | |
67e6b629 | 398 | struct dccp_request_sock *dreq; |
118b2c95 | 399 | const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
7c657876 ACM |
400 | sizeof(struct dccp_hdr_ext) + |
401 | sizeof(struct dccp_hdr_response); | |
802885fc ED |
402 | struct sk_buff *skb; |
403 | ||
404 | /* sk is marked const to clearly express we dont hold socket lock. | |
405 | * sock_wmalloc() will atomically change sk->sk_wmem_alloc, | |
406 | * it is safe to promote sk to non const. | |
407 | */ | |
408 | skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1, | |
409 | GFP_ATOMIC); | |
410 | if (!skb) | |
7c657876 ACM |
411 | return NULL; |
412 | ||
802885fc | 413 | skb_reserve(skb, MAX_DCCP_HEADER); |
7c657876 | 414 | |
adf30907 | 415 | skb_dst_set(skb, dst_clone(dst)); |
7c657876 | 416 | |
67e6b629 | 417 | dreq = dccp_rsk(req); |
f541fb7e SJ |
418 | if (inet_rsk(req)->acked) /* increase GSS upon retransmission */ |
419 | dccp_inc_seqno(&dreq->dreq_gss); | |
7c657876 | 420 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
f541fb7e | 421 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_gss; |
2d0817d1 | 422 | |
0c116839 GR |
423 | /* Resolve feature dependencies resulting from choice of CCID */ |
424 | if (dccp_feat_server_ccid_dependencies(dreq)) | |
425 | goto response_failed; | |
426 | ||
427 | if (dccp_insert_options_rsk(dreq, skb)) | |
428 | goto response_failed; | |
7c657876 | 429 | |
09dbc389 | 430 | /* Build and checksum header */ |
9b42078e | 431 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 432 | |
b44084c2 | 433 | dh->dccph_sport = htons(inet_rsk(req)->ir_num); |
634fb979 | 434 | dh->dccph_dport = inet_rsk(req)->ir_rmt_port; |
7690af3f ACM |
435 | dh->dccph_doff = (dccp_header_size + |
436 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
437 | dh->dccph_type = DCCP_PKT_RESPONSE; |
438 | dh->dccph_x = 1; | |
f541fb7e SJ |
439 | dccp_hdr_set_seq(dh, dreq->dreq_gss); |
440 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_gsr); | |
67e6b629 | 441 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; |
7c657876 | 442 | |
6f4e5fff GR |
443 | dccp_csum_outgoing(skb); |
444 | ||
e11d9d30 GR |
445 | /* We use `acked' to remember that a Response was already sent. */ |
446 | inet_rsk(req)->acked = 1; | |
7c657876 ACM |
447 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
448 | return skb; | |
0c116839 GR |
449 | response_failed: |
450 | kfree_skb(skb); | |
451 | return NULL; | |
7c657876 ACM |
452 | } |
453 | ||
f21e68ca ACM |
454 | EXPORT_SYMBOL_GPL(dccp_make_response); |
455 | ||
e356d37a | 456 | /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
7630f026 | 457 | struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
e356d37a GR |
458 | { |
459 | struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; | |
460 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); | |
461 | const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + | |
462 | sizeof(struct dccp_hdr_ext) + | |
463 | sizeof(struct dccp_hdr_reset); | |
464 | struct dccp_hdr_reset *dhr; | |
465 | struct sk_buff *skb; | |
466 | ||
7630f026 | 467 | skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
e356d37a GR |
468 | if (skb == NULL) |
469 | return NULL; | |
470 | ||
7630f026 | 471 | skb_reserve(skb, sk->sk_prot->max_header); |
e356d37a GR |
472 | |
473 | /* Swap the send and the receive. */ | |
474 | dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); | |
475 | dh->dccph_type = DCCP_PKT_RESET; | |
476 | dh->dccph_sport = rxdh->dccph_dport; | |
477 | dh->dccph_dport = rxdh->dccph_sport; | |
478 | dh->dccph_doff = dccp_hdr_reset_len / 4; | |
479 | dh->dccph_x = 1; | |
480 | ||
481 | dhr = dccp_hdr_reset(skb); | |
482 | dhr->dccph_reset_code = dcb->dccpd_reset_code; | |
483 | ||
484 | switch (dcb->dccpd_reset_code) { | |
485 | case DCCP_RESET_CODE_PACKET_ERROR: | |
486 | dhr->dccph_reset_data[0] = rxdh->dccph_type; | |
487 | break; | |
488 | case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */ | |
489 | case DCCP_RESET_CODE_MANDATORY_ERROR: | |
490 | memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); | |
491 | break; | |
492 | } | |
493 | /* | |
494 | * From RFC 4340, 8.3.1: | |
495 | * If P.ackno exists, set R.seqno := P.ackno + 1. | |
496 | * Else set R.seqno := 0. | |
497 | */ | |
498 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
499 | dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); | |
500 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); | |
501 | ||
502 | dccp_csum_outgoing(skb); | |
503 | return skb; | |
504 | } | |
505 | ||
506 | EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); | |
507 | ||
ee1a1592 | 508 | /* send Reset on established socket, to close or abort the connection */ |
017487d7 ACM |
509 | int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
510 | { | |
ee1a1592 | 511 | struct sk_buff *skb; |
017487d7 ACM |
512 | /* |
513 | * FIXME: what if rebuild_header fails? | |
514 | * Should we be doing a rebuild_header here? | |
515 | */ | |
f53dc67c | 516 | int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
017487d7 | 517 | |
ee1a1592 GR |
518 | if (err != 0) |
519 | return err; | |
520 | ||
521 | skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); | |
522 | if (skb == NULL) | |
523 | return -ENOBUFS; | |
524 | ||
525 | /* Reserve space for headers and prepare control bits. */ | |
526 | skb_reserve(skb, sk->sk_prot->max_header); | |
527 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
528 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
017487d7 | 529 | |
ee1a1592 | 530 | return dccp_transmit_skb(sk, skb); |
017487d7 ACM |
531 | } |
532 | ||
7c657876 ACM |
533 | /* |
534 | * Do all connect socket setups that can be done AF independent. | |
535 | */ | |
93344af4 | 536 | int dccp_connect(struct sock *sk) |
7c657876 | 537 | { |
93344af4 | 538 | struct sk_buff *skb; |
f21e68ca | 539 | struct dccp_sock *dp = dccp_sk(sk); |
7c657876 ACM |
540 | struct dst_entry *dst = __sk_dst_get(sk); |
541 | struct inet_connection_sock *icsk = inet_csk(sk); | |
542 | ||
543 | sk->sk_err = 0; | |
544 | sock_reset_flag(sk, SOCK_DONE); | |
c9eaf173 | 545 | |
7c657876 ACM |
546 | dccp_sync_mss(sk, dst_mtu(dst)); |
547 | ||
9eca0a47 GR |
548 | /* do not connect if feature negotiation setup fails */ |
549 | if (dccp_feat_finalise_settings(dccp_sk(sk))) | |
550 | return -EPROTO; | |
551 | ||
93344af4 GR |
552 | /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ |
553 | dp->dccps_gar = dp->dccps_iss; | |
7c657876 | 554 | |
118b2c95 | 555 | skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
7c657876 ACM |
556 | if (unlikely(skb == NULL)) |
557 | return -ENOBUFS; | |
558 | ||
559 | /* Reserve space for headers. */ | |
118b2c95 | 560 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
561 | |
562 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 | 563 | |
8695e801 | 564 | dccp_transmit_skb(sk, dccp_skb_entail(sk, skb)); |
7c657876 ACM |
565 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); |
566 | ||
567 | /* Timer for repeating the REQUEST until an answer. */ | |
93344af4 | 568 | icsk->icsk_retransmits = 0; |
27258ee5 ACM |
569 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
570 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
571 | return 0; |
572 | } | |
573 | ||
f21e68ca ACM |
574 | EXPORT_SYMBOL_GPL(dccp_connect); |
575 | ||
7c657876 ACM |
576 | void dccp_send_ack(struct sock *sk) |
577 | { | |
578 | /* If we have been reset, we may not send again. */ | |
579 | if (sk->sk_state != DCCP_CLOSED) { | |
118b2c95 ACM |
580 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
581 | GFP_ATOMIC); | |
7c657876 ACM |
582 | |
583 | if (skb == NULL) { | |
584 | inet_csk_schedule_ack(sk); | |
585 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
586 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
587 | TCP_DELACK_MAX, | |
588 | DCCP_RTO_MAX); | |
7c657876 ACM |
589 | return; |
590 | } | |
591 | ||
592 | /* Reserve space for headers */ | |
118b2c95 | 593 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 594 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
7c657876 ACM |
595 | dccp_transmit_skb(sk, skb); |
596 | } | |
597 | } | |
598 | ||
599 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
600 | ||
1e2f0e5e | 601 | #if 0 |
727ecc5f | 602 | /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
7c657876 ACM |
603 | void dccp_send_delayed_ack(struct sock *sk) |
604 | { | |
605 | struct inet_connection_sock *icsk = inet_csk(sk); | |
606 | /* | |
607 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
608 | * with using 2s, and active senders also piggyback the ACK into a | |
609 | * DATAACK packet, so this is really for quiescent senders. | |
610 | */ | |
611 | unsigned long timeout = jiffies + 2 * HZ; | |
612 | ||
613 | /* Use new timeout only if there wasn't a older one earlier. */ | |
614 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
615 | /* If delack timer was blocked or is about to expire, | |
616 | * send ACK now. | |
617 | * | |
618 | * FIXME: check the "about to expire" part | |
619 | */ | |
620 | if (icsk->icsk_ack.blocked) { | |
621 | dccp_send_ack(sk); | |
622 | return; | |
623 | } | |
624 | ||
625 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
626 | timeout = icsk->icsk_ack.timeout; | |
627 | } | |
628 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
629 | icsk->icsk_ack.timeout = timeout; | |
630 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
631 | } | |
1e2f0e5e | 632 | #endif |
7c657876 | 633 | |
b0d045ca | 634 | void dccp_send_sync(struct sock *sk, const u64 ackno, |
e92ae93a | 635 | const enum dccp_pkt_type pkt_type) |
7c657876 ACM |
636 | { |
637 | /* | |
638 | * We are not putting this on the write queue, so | |
639 | * dccp_transmit_skb() will set the ownership to this | |
640 | * sock. | |
641 | */ | |
118b2c95 | 642 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
7c657876 | 643 | |
b0d045ca | 644 | if (skb == NULL) { |
7c657876 | 645 | /* FIXME: how to make sure the sync is sent? */ |
b0d045ca | 646 | DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
7c657876 | 647 | return; |
b0d045ca | 648 | } |
7c657876 ACM |
649 | |
650 | /* Reserve space for headers and prepare control bits. */ | |
118b2c95 | 651 | skb_reserve(skb, sk->sk_prot->max_header); |
e92ae93a | 652 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
b0d045ca | 653 | DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
7c657876 | 654 | |
d83447f0 GR |
655 | /* |
656 | * Clear the flag in case the Sync was scheduled for out-of-band data, | |
657 | * such as carrying a long Ack Vector. | |
658 | */ | |
659 | dccp_sk(sk)->dccps_sync_scheduled = 0; | |
660 | ||
7c657876 ACM |
661 | dccp_transmit_skb(sk, skb); |
662 | } | |
663 | ||
b61fafc4 ACM |
664 | EXPORT_SYMBOL_GPL(dccp_send_sync); |
665 | ||
7690af3f ACM |
666 | /* |
667 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
668 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
669 | * any circumstances. | |
7c657876 | 670 | */ |
7ad07e7c | 671 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
672 | { |
673 | struct dccp_sock *dp = dccp_sk(sk); | |
674 | struct sk_buff *skb; | |
7d877f3b | 675 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 676 | |
7ad07e7c ACM |
677 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
678 | if (skb == NULL) | |
679 | return; | |
7c657876 ACM |
680 | |
681 | /* Reserve space for headers and prepare control bits. */ | |
682 | skb_reserve(skb, sk->sk_prot->max_header); | |
b8599d20 GR |
683 | if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
684 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; | |
685 | else | |
686 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; | |
7c657876 | 687 | |
7ad07e7c | 688 | if (active) { |
8695e801 | 689 | skb = dccp_skb_entail(sk, skb); |
92d31920 GR |
690 | /* |
691 | * Retransmission timer for active-close: RFC 4340, 8.3 requires | |
692 | * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ | |
693 | * state can be left. The initial timeout is 2 RTTs. | |
694 | * Since RTT measurement is done by the CCIDs, there is no easy | |
695 | * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 | |
696 | * is too low (200ms); we use a high value to avoid unnecessary | |
697 | * retransmissions when the link RTT is > 0.2 seconds. | |
698 | * FIXME: Let main module sample RTTs and use that instead. | |
699 | */ | |
700 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
701 | DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); | |
8695e801 GR |
702 | } |
703 | dccp_transmit_skb(sk, skb); | |
7c657876 | 704 | } |