Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7c657876 ACM |
2 | /* |
3 | * net/dccp/output.c | |
8109b02b | 4 | * |
7c657876 ACM |
5 | * An implementation of the DCCP protocol |
6 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
7c657876 ACM |
7 | */ |
8 | ||
7c657876 | 9 | #include <linux/dccp.h> |
48918a4d | 10 | #include <linux/kernel.h> |
7c657876 | 11 | #include <linux/skbuff.h> |
5a0e3ad6 | 12 | #include <linux/slab.h> |
174cd4b1 | 13 | #include <linux/sched/signal.h> |
7c657876 | 14 | |
14c85021 | 15 | #include <net/inet_sock.h> |
7c657876 ACM |
16 | #include <net/sock.h> |
17 | ||
ae31c339 | 18 | #include "ackvec.h" |
7c657876 ACM |
19 | #include "ccid.h" |
20 | #include "dccp.h" | |
21 | ||
22 | static inline void dccp_event_ack_sent(struct sock *sk) | |
23 | { | |
24 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
25 | } | |
26 | ||
8695e801 GR |
27 | /* enqueue @skb on sk_send_head for retransmission, return clone to send now */ |
28 | static struct sk_buff *dccp_skb_entail(struct sock *sk, struct sk_buff *skb) | |
48918a4d HX |
29 | { |
30 | skb_set_owner_w(skb, sk); | |
31 | WARN_ON(sk->sk_send_head); | |
32 | sk->sk_send_head = skb; | |
8695e801 | 33 | return skb_clone(sk->sk_send_head, gfp_any()); |
48918a4d HX |
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)) { | |
d9d8da80 | 45 | 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; | |
df561f66 | 65 | fallthrough; |
edc9e819 | 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; | |
df561f66 | 75 | fallthrough; |
afe00251 | 76 | |
7c657876 ACM |
77 | case DCCP_PKT_SYNC: |
78 | case DCCP_PKT_SYNCACK: | |
b0d045ca | 79 | ackno = dcb->dccpd_ack_seq; |
df561f66 | 80 | fallthrough; |
edc9e819 HX |
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 | 101 | dh->dccph_type = dcb->dccpd_type; |
c720c7e8 ED |
102 | dh->dccph_sport = inet->inet_sport; |
103 | dh->dccph_dport = inet->inet_dport; | |
7c657876 ACM |
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 | ||
bb296246 | 131 | icsk->icsk_af_ops->send_check(sk, 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 | ||
b0270e91 | 138 | err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl); |
b9df3cb8 | 139 | return net_xmit_eval(err); |
7c657876 ACM |
140 | } |
141 | return -ENOBUFS; | |
142 | } | |
143 | ||
6179983a | 144 | /** |
25985edc | 145 | * dccp_determine_ccmps - Find out about CCID-specific packet-size limits |
0b609b55 AL |
146 | * @dp: socket to find packet size limits of |
147 | * | |
6179983a GR |
148 | * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), |
149 | * since the RX CCID is restricted to feedback packets (Acks), which are small | |
150 | * in comparison with the data traffic. A value of 0 means "no current CCMPS". | |
151 | */ | |
152 | static u32 dccp_determine_ccmps(const struct dccp_sock *dp) | |
153 | { | |
154 | const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; | |
155 | ||
156 | if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) | |
157 | return 0; | |
158 | return tx_ccid->ccid_ops->ccid_ccmps; | |
159 | } | |
160 | ||
7c657876 ACM |
161 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
162 | { | |
d83d8461 | 163 | struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 | 164 | struct dccp_sock *dp = dccp_sk(sk); |
6179983a | 165 | u32 ccmps = dccp_determine_ccmps(dp); |
361a5c1d | 166 | u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; |
7c657876 | 167 | |
6179983a GR |
168 | /* Account for header lengths and IPv4/v6 option overhead */ |
169 | cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + | |
170 | sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); | |
7c657876 ACM |
171 | |
172 | /* | |
361a5c1d GR |
173 | * Leave enough headroom for common DCCP header options. |
174 | * This only considers options which may appear on DCCP-Data packets, as | |
175 | * per table 3 in RFC 4340, 5.8. When running out of space for other | |
176 | * options (eg. Ack Vector which can take up to 255 bytes), it is better | |
177 | * to schedule a separate Ack. Thus we leave headroom for the following: | |
178 | * - 1 byte for Slow Receiver (11.6) | |
179 | * - 6 bytes for Timestamp (13.1) | |
180 | * - 10 bytes for Timestamp Echo (13.3) | |
181 | * - 8 bytes for NDP count (7.7, when activated) | |
182 | * - 6 bytes for Data Checksum (9.3) | |
183 | * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled) | |
7c657876 | 184 | */ |
361a5c1d GR |
185 | cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 + |
186 | (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4); | |
7c657876 ACM |
187 | |
188 | /* And store cached results */ | |
d83d8461 | 189 | icsk->icsk_pmtu_cookie = pmtu; |
a47e598f | 190 | WRITE_ONCE(dp->dccps_mss_cache, cur_mps); |
7c657876 | 191 | |
6179983a | 192 | return cur_mps; |
7c657876 ACM |
193 | } |
194 | ||
f21e68ca ACM |
195 | EXPORT_SYMBOL_GPL(dccp_sync_mss); |
196 | ||
c530cfb1 ACM |
197 | void dccp_write_space(struct sock *sk) |
198 | { | |
43815482 | 199 | struct socket_wq *wq; |
c530cfb1 | 200 | |
43815482 ED |
201 | rcu_read_lock(); |
202 | wq = rcu_dereference(sk->sk_wq); | |
1ce0bf50 | 203 | if (skwq_has_sleeper(wq)) |
43815482 | 204 | wake_up_interruptible(&wq->wait); |
c530cfb1 ACM |
205 | /* Should agree with poll, otherwise some programs break */ |
206 | if (sock_writeable(sk)) | |
1abe267f | 207 | sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT); |
c530cfb1 | 208 | |
43815482 | 209 | rcu_read_unlock(); |
c530cfb1 ACM |
210 | } |
211 | ||
d6809c12 | 212 | /** |
b1fcf55e | 213 | * dccp_wait_for_ccid - Await CCID send permission |
bc849872 | 214 | * @sk: socket to wait for |
b1fcf55e | 215 | * @delay: timeout in jiffies |
2c53040f | 216 | * |
b1fcf55e | 217 | * This is used by CCIDs which need to delay the send time in process context. |
d6809c12 | 218 | */ |
b1fcf55e | 219 | static int dccp_wait_for_ccid(struct sock *sk, unsigned long delay) |
d6809c12 | 220 | { |
d6809c12 | 221 | DEFINE_WAIT(wait); |
b1fcf55e | 222 | long remaining; |
d6809c12 | 223 | |
b1fcf55e GR |
224 | prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); |
225 | sk->sk_write_pending++; | |
226 | release_sock(sk); | |
bc849872 | 227 | |
b1fcf55e | 228 | remaining = schedule_timeout(delay); |
d6809c12 | 229 | |
b1fcf55e GR |
230 | lock_sock(sk); |
231 | sk->sk_write_pending--; | |
aa395145 | 232 | finish_wait(sk_sleep(sk), &wait); |
b1fcf55e GR |
233 | |
234 | if (signal_pending(current) || sk->sk_err) | |
235 | return -1; | |
236 | return remaining; | |
d6809c12 ACM |
237 | } |
238 | ||
dc841e30 GR |
239 | /** |
240 | * dccp_xmit_packet - Send data packet under control of CCID | |
0b609b55 AL |
241 | * @sk: socket to send data packet on |
242 | * | |
dc841e30 GR |
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 | |
0b609b55 AL |
303 | * @sk: socket to be drained |
304 | * @time_budget: time allowed to drain the queue | |
305 | * | |
b1fcf55e GR |
306 | * Since dccp_sendmsg queues packets without waiting for them to be sent, it may |
307 | * happen that the TX queue is not empty at the end of a connection. We give the | |
308 | * HC-sender CCID a grace period of up to @time_budget jiffies. If this function | |
309 | * returns with a non-empty write queue, it will be purged later. | |
310 | */ | |
311 | void dccp_flush_write_queue(struct sock *sk, long *time_budget) | |
312 | { | |
313 | struct dccp_sock *dp = dccp_sk(sk); | |
314 | struct sk_buff *skb; | |
315 | long delay, rc; | |
316 | ||
317 | while (*time_budget > 0 && (skb = skb_peek(&sk->sk_write_queue))) { | |
318 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); | |
319 | ||
320 | switch (ccid_packet_dequeue_eval(rc)) { | |
321 | case CCID_PACKET_WILL_DEQUEUE_LATER: | |
322 | /* | |
323 | * If the CCID determines when to send, the next sending | |
324 | * time is unknown or the CCID may not even send again | |
325 | * (e.g. remote host crashes or lost Ack packets). | |
326 | */ | |
327 | DCCP_WARN("CCID did not manage to send all packets\n"); | |
328 | return; | |
329 | case CCID_PACKET_DELAY: | |
330 | delay = msecs_to_jiffies(rc); | |
331 | if (delay > *time_budget) | |
332 | return; | |
333 | rc = dccp_wait_for_ccid(sk, delay); | |
334 | if (rc < 0) | |
335 | return; | |
336 | *time_budget -= (delay - rc); | |
337 | /* check again if we can send now */ | |
338 | break; | |
339 | case CCID_PACKET_SEND_AT_ONCE: | |
340 | dccp_xmit_packet(sk); | |
341 | break; | |
342 | case CCID_PACKET_ERR: | |
343 | skb_dequeue(&sk->sk_write_queue); | |
344 | kfree_skb(skb); | |
345 | dccp_pr_debug("packet discarded due to err=%ld\n", rc); | |
346 | } | |
347 | } | |
348 | } | |
349 | ||
350 | void dccp_write_xmit(struct sock *sk) | |
27258ee5 | 351 | { |
97e5848d IM |
352 | struct dccp_sock *dp = dccp_sk(sk); |
353 | struct sk_buff *skb; | |
97e5848d | 354 | |
871a2c16 | 355 | while ((skb = dccp_qpolicy_top(sk))) { |
dc841e30 | 356 | int rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
d6809c12 | 357 | |
dc841e30 GR |
358 | switch (ccid_packet_dequeue_eval(rc)) { |
359 | case CCID_PACKET_WILL_DEQUEUE_LATER: | |
360 | return; | |
361 | case CCID_PACKET_DELAY: | |
b1fcf55e GR |
362 | sk_reset_timer(sk, &dp->dccps_xmit_timer, |
363 | jiffies + msecs_to_jiffies(rc)); | |
364 | return; | |
dc841e30 GR |
365 | case CCID_PACKET_SEND_AT_ONCE: |
366 | dccp_xmit_packet(sk); | |
367 | break; | |
368 | case CCID_PACKET_ERR: | |
871a2c16 | 369 | dccp_qpolicy_drop(sk, skb); |
dc841e30 | 370 | dccp_pr_debug("packet discarded due to err=%d\n", rc); |
f6282f4d | 371 | } |
97e5848d | 372 | } |
27258ee5 ACM |
373 | } |
374 | ||
59435444 GR |
375 | /** |
376 | * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets | |
0b609b55 AL |
377 | * @sk: socket to perform retransmit on |
378 | * | |
59435444 GR |
379 | * There are only four retransmittable packet types in DCCP: |
380 | * - Request in client-REQUEST state (sec. 8.1.1), | |
381 | * - CloseReq in server-CLOSEREQ state (sec. 8.3), | |
382 | * - Close in node-CLOSING state (sec. 8.3), | |
383 | * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). | |
384 | * This function expects sk->sk_send_head to contain the original skb. | |
385 | */ | |
386 | int dccp_retransmit_skb(struct sock *sk) | |
7c657876 | 387 | { |
59435444 GR |
388 | WARN_ON(sk->sk_send_head == NULL); |
389 | ||
57cca05a | 390 | if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) |
7c657876 ACM |
391 | return -EHOSTUNREACH; /* Routing failure or similar. */ |
392 | ||
59435444 GR |
393 | /* this count is used to distinguish original and retransmitted skb */ |
394 | inet_csk(sk)->icsk_retransmits++; | |
395 | ||
396 | return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); | |
7c657876 ACM |
397 | } |
398 | ||
802885fc | 399 | struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst, |
7c657876 ACM |
400 | struct request_sock *req) |
401 | { | |
402 | struct dccp_hdr *dh; | |
67e6b629 | 403 | struct dccp_request_sock *dreq; |
118b2c95 | 404 | const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
7c657876 ACM |
405 | sizeof(struct dccp_hdr_ext) + |
406 | sizeof(struct dccp_hdr_response); | |
802885fc ED |
407 | struct sk_buff *skb; |
408 | ||
409 | /* sk is marked const to clearly express we dont hold socket lock. | |
410 | * sock_wmalloc() will atomically change sk->sk_wmem_alloc, | |
411 | * it is safe to promote sk to non const. | |
412 | */ | |
413 | skb = sock_wmalloc((struct sock *)sk, MAX_DCCP_HEADER, 1, | |
414 | GFP_ATOMIC); | |
415 | if (!skb) | |
7c657876 ACM |
416 | return NULL; |
417 | ||
802885fc | 418 | skb_reserve(skb, MAX_DCCP_HEADER); |
7c657876 | 419 | |
adf30907 | 420 | skb_dst_set(skb, dst_clone(dst)); |
7c657876 | 421 | |
67e6b629 | 422 | dreq = dccp_rsk(req); |
f541fb7e SJ |
423 | if (inet_rsk(req)->acked) /* increase GSS upon retransmission */ |
424 | dccp_inc_seqno(&dreq->dreq_gss); | |
7c657876 | 425 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
f541fb7e | 426 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_gss; |
2d0817d1 | 427 | |
0c116839 GR |
428 | /* Resolve feature dependencies resulting from choice of CCID */ |
429 | if (dccp_feat_server_ccid_dependencies(dreq)) | |
430 | goto response_failed; | |
431 | ||
432 | if (dccp_insert_options_rsk(dreq, skb)) | |
433 | goto response_failed; | |
7c657876 | 434 | |
09dbc389 | 435 | /* Build and checksum header */ |
9b42078e | 436 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 437 | |
b44084c2 | 438 | dh->dccph_sport = htons(inet_rsk(req)->ir_num); |
634fb979 | 439 | dh->dccph_dport = inet_rsk(req)->ir_rmt_port; |
7690af3f ACM |
440 | dh->dccph_doff = (dccp_header_size + |
441 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
442 | dh->dccph_type = DCCP_PKT_RESPONSE; |
443 | dh->dccph_x = 1; | |
f541fb7e SJ |
444 | dccp_hdr_set_seq(dh, dreq->dreq_gss); |
445 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_gsr); | |
67e6b629 | 446 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; |
7c657876 | 447 | |
6f4e5fff GR |
448 | dccp_csum_outgoing(skb); |
449 | ||
e11d9d30 GR |
450 | /* We use `acked' to remember that a Response was already sent. */ |
451 | inet_rsk(req)->acked = 1; | |
7c657876 ACM |
452 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
453 | return skb; | |
0c116839 GR |
454 | response_failed: |
455 | kfree_skb(skb); | |
456 | return NULL; | |
7c657876 ACM |
457 | } |
458 | ||
f21e68ca ACM |
459 | EXPORT_SYMBOL_GPL(dccp_make_response); |
460 | ||
e356d37a | 461 | /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
7630f026 | 462 | struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
e356d37a GR |
463 | { |
464 | struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; | |
465 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); | |
466 | const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + | |
467 | sizeof(struct dccp_hdr_ext) + | |
468 | sizeof(struct dccp_hdr_reset); | |
469 | struct dccp_hdr_reset *dhr; | |
470 | struct sk_buff *skb; | |
471 | ||
7630f026 | 472 | skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
e356d37a GR |
473 | if (skb == NULL) |
474 | return NULL; | |
475 | ||
7630f026 | 476 | skb_reserve(skb, sk->sk_prot->max_header); |
e356d37a GR |
477 | |
478 | /* Swap the send and the receive. */ | |
479 | dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); | |
480 | dh->dccph_type = DCCP_PKT_RESET; | |
481 | dh->dccph_sport = rxdh->dccph_dport; | |
482 | dh->dccph_dport = rxdh->dccph_sport; | |
483 | dh->dccph_doff = dccp_hdr_reset_len / 4; | |
484 | dh->dccph_x = 1; | |
485 | ||
486 | dhr = dccp_hdr_reset(skb); | |
487 | dhr->dccph_reset_code = dcb->dccpd_reset_code; | |
488 | ||
489 | switch (dcb->dccpd_reset_code) { | |
490 | case DCCP_RESET_CODE_PACKET_ERROR: | |
491 | dhr->dccph_reset_data[0] = rxdh->dccph_type; | |
492 | break; | |
df561f66 | 493 | case DCCP_RESET_CODE_OPTION_ERROR: |
e356d37a GR |
494 | case DCCP_RESET_CODE_MANDATORY_ERROR: |
495 | memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); | |
496 | break; | |
497 | } | |
498 | /* | |
499 | * From RFC 4340, 8.3.1: | |
500 | * If P.ackno exists, set R.seqno := P.ackno + 1. | |
501 | * Else set R.seqno := 0. | |
502 | */ | |
503 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
504 | dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); | |
505 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); | |
506 | ||
507 | dccp_csum_outgoing(skb); | |
508 | return skb; | |
509 | } | |
510 | ||
511 | EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); | |
512 | ||
ee1a1592 | 513 | /* send Reset on established socket, to close or abort the connection */ |
017487d7 ACM |
514 | int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
515 | { | |
ee1a1592 | 516 | struct sk_buff *skb; |
017487d7 ACM |
517 | /* |
518 | * FIXME: what if rebuild_header fails? | |
519 | * Should we be doing a rebuild_header here? | |
520 | */ | |
f53dc67c | 521 | int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
017487d7 | 522 | |
ee1a1592 GR |
523 | if (err != 0) |
524 | return err; | |
525 | ||
526 | skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); | |
527 | if (skb == NULL) | |
528 | return -ENOBUFS; | |
529 | ||
530 | /* Reserve space for headers and prepare control bits. */ | |
531 | skb_reserve(skb, sk->sk_prot->max_header); | |
532 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
533 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
017487d7 | 534 | |
ee1a1592 | 535 | return dccp_transmit_skb(sk, skb); |
017487d7 ACM |
536 | } |
537 | ||
7c657876 ACM |
538 | /* |
539 | * Do all connect socket setups that can be done AF independent. | |
540 | */ | |
93344af4 | 541 | int dccp_connect(struct sock *sk) |
7c657876 | 542 | { |
93344af4 | 543 | struct sk_buff *skb; |
f21e68ca | 544 | struct dccp_sock *dp = dccp_sk(sk); |
7c657876 ACM |
545 | struct dst_entry *dst = __sk_dst_get(sk); |
546 | struct inet_connection_sock *icsk = inet_csk(sk); | |
547 | ||
548 | sk->sk_err = 0; | |
549 | sock_reset_flag(sk, SOCK_DONE); | |
c9eaf173 | 550 | |
7c657876 ACM |
551 | dccp_sync_mss(sk, dst_mtu(dst)); |
552 | ||
9eca0a47 GR |
553 | /* do not connect if feature negotiation setup fails */ |
554 | if (dccp_feat_finalise_settings(dccp_sk(sk))) | |
555 | return -EPROTO; | |
556 | ||
93344af4 GR |
557 | /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ |
558 | dp->dccps_gar = dp->dccps_iss; | |
7c657876 | 559 | |
118b2c95 | 560 | skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
7c657876 ACM |
561 | if (unlikely(skb == NULL)) |
562 | return -ENOBUFS; | |
563 | ||
564 | /* Reserve space for headers. */ | |
118b2c95 | 565 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
566 | |
567 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 | 568 | |
8695e801 | 569 | dccp_transmit_skb(sk, dccp_skb_entail(sk, skb)); |
7c657876 ACM |
570 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); |
571 | ||
572 | /* Timer for repeating the REQUEST until an answer. */ | |
93344af4 | 573 | icsk->icsk_retransmits = 0; |
27258ee5 ACM |
574 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
575 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
576 | return 0; |
577 | } | |
578 | ||
f21e68ca ACM |
579 | EXPORT_SYMBOL_GPL(dccp_connect); |
580 | ||
7c657876 ACM |
581 | void dccp_send_ack(struct sock *sk) |
582 | { | |
583 | /* If we have been reset, we may not send again. */ | |
584 | if (sk->sk_state != DCCP_CLOSED) { | |
118b2c95 ACM |
585 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
586 | GFP_ATOMIC); | |
7c657876 ACM |
587 | |
588 | if (skb == NULL) { | |
589 | inet_csk_schedule_ack(sk); | |
590 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
591 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
592 | TCP_DELACK_MAX, | |
593 | DCCP_RTO_MAX); | |
7c657876 ACM |
594 | return; |
595 | } | |
596 | ||
597 | /* Reserve space for headers */ | |
118b2c95 | 598 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 599 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
7c657876 ACM |
600 | dccp_transmit_skb(sk, skb); |
601 | } | |
602 | } | |
603 | ||
604 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
605 | ||
1e2f0e5e | 606 | #if 0 |
727ecc5f | 607 | /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
7c657876 ACM |
608 | void dccp_send_delayed_ack(struct sock *sk) |
609 | { | |
610 | struct inet_connection_sock *icsk = inet_csk(sk); | |
611 | /* | |
612 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
613 | * with using 2s, and active senders also piggyback the ACK into a | |
614 | * DATAACK packet, so this is really for quiescent senders. | |
615 | */ | |
616 | unsigned long timeout = jiffies + 2 * HZ; | |
617 | ||
618 | /* Use new timeout only if there wasn't a older one earlier. */ | |
619 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
620 | /* If delack timer was blocked or is about to expire, | |
621 | * send ACK now. | |
622 | * | |
623 | * FIXME: check the "about to expire" part | |
624 | */ | |
625 | if (icsk->icsk_ack.blocked) { | |
626 | dccp_send_ack(sk); | |
627 | return; | |
628 | } | |
629 | ||
630 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
631 | timeout = icsk->icsk_ack.timeout; | |
632 | } | |
633 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
634 | icsk->icsk_ack.timeout = timeout; | |
635 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
636 | } | |
1e2f0e5e | 637 | #endif |
7c657876 | 638 | |
b0d045ca | 639 | void dccp_send_sync(struct sock *sk, const u64 ackno, |
e92ae93a | 640 | const enum dccp_pkt_type pkt_type) |
7c657876 ACM |
641 | { |
642 | /* | |
643 | * We are not putting this on the write queue, so | |
644 | * dccp_transmit_skb() will set the ownership to this | |
645 | * sock. | |
646 | */ | |
118b2c95 | 647 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
7c657876 | 648 | |
b0d045ca | 649 | if (skb == NULL) { |
7c657876 | 650 | /* FIXME: how to make sure the sync is sent? */ |
b0d045ca | 651 | DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
7c657876 | 652 | return; |
b0d045ca | 653 | } |
7c657876 ACM |
654 | |
655 | /* Reserve space for headers and prepare control bits. */ | |
118b2c95 | 656 | skb_reserve(skb, sk->sk_prot->max_header); |
e92ae93a | 657 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
b0d045ca | 658 | DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
7c657876 | 659 | |
d83447f0 GR |
660 | /* |
661 | * Clear the flag in case the Sync was scheduled for out-of-band data, | |
662 | * such as carrying a long Ack Vector. | |
663 | */ | |
664 | dccp_sk(sk)->dccps_sync_scheduled = 0; | |
665 | ||
7c657876 ACM |
666 | dccp_transmit_skb(sk, skb); |
667 | } | |
668 | ||
b61fafc4 ACM |
669 | EXPORT_SYMBOL_GPL(dccp_send_sync); |
670 | ||
7690af3f ACM |
671 | /* |
672 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
673 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
674 | * any circumstances. | |
7c657876 | 675 | */ |
7ad07e7c | 676 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
677 | { |
678 | struct dccp_sock *dp = dccp_sk(sk); | |
679 | struct sk_buff *skb; | |
7d877f3b | 680 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 681 | |
7ad07e7c ACM |
682 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
683 | if (skb == NULL) | |
684 | return; | |
7c657876 ACM |
685 | |
686 | /* Reserve space for headers and prepare control bits. */ | |
687 | skb_reserve(skb, sk->sk_prot->max_header); | |
b8599d20 GR |
688 | if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
689 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; | |
690 | else | |
691 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; | |
7c657876 | 692 | |
7ad07e7c | 693 | if (active) { |
8695e801 | 694 | skb = dccp_skb_entail(sk, skb); |
92d31920 GR |
695 | /* |
696 | * Retransmission timer for active-close: RFC 4340, 8.3 requires | |
697 | * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ | |
698 | * state can be left. The initial timeout is 2 RTTs. | |
699 | * Since RTT measurement is done by the CCIDs, there is no easy | |
700 | * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 | |
701 | * is too low (200ms); we use a high value to avoid unnecessary | |
702 | * retransmissions when the link RTT is > 0.2 seconds. | |
703 | * FIXME: Let main module sample RTTs and use that instead. | |
704 | */ | |
705 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
706 | DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); | |
8695e801 GR |
707 | } |
708 | dccp_transmit_skb(sk, skb); | |
7c657876 | 709 | } |