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> |
7c657876 | 17 | |
14c85021 | 18 | #include <net/inet_sock.h> |
7c657876 ACM |
19 | #include <net/sock.h> |
20 | ||
ae31c339 | 21 | #include "ackvec.h" |
7c657876 ACM |
22 | #include "ccid.h" |
23 | #include "dccp.h" | |
24 | ||
25 | static inline void dccp_event_ack_sent(struct sock *sk) | |
26 | { | |
27 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); | |
28 | } | |
29 | ||
c25a18ba | 30 | static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb) |
48918a4d HX |
31 | { |
32 | skb_set_owner_w(skb, sk); | |
33 | WARN_ON(sk->sk_send_head); | |
34 | sk->sk_send_head = skb; | |
35 | } | |
36 | ||
7c657876 ACM |
37 | /* |
38 | * All SKB's seen here are completely headerless. It is our | |
39 | * job to build the DCCP header, and pass the packet down to | |
40 | * IP so it can do the same plus pass the packet off to the | |
41 | * device. | |
42 | */ | |
48918a4d | 43 | static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
44 | { |
45 | if (likely(skb != NULL)) { | |
46 | const struct inet_sock *inet = inet_sk(sk); | |
57cca05a | 47 | const struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 ACM |
48 | struct dccp_sock *dp = dccp_sk(sk); |
49 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
50 | struct dccp_hdr *dh; | |
51 | /* XXX For now we're using only 48 bits sequence numbers */ | |
118b2c95 | 52 | const u32 dccp_header_size = sizeof(*dh) + |
7c657876 | 53 | sizeof(struct dccp_hdr_ext) + |
7690af3f | 54 | dccp_packet_hdr_len(dcb->dccpd_type); |
7c657876 ACM |
55 | int err, set_ack = 1; |
56 | u64 ackno = dp->dccps_gsr; | |
73f18fdb GR |
57 | /* |
58 | * Increment GSS here already in case the option code needs it. | |
59 | * Update GSS for real only if option processing below succeeds. | |
60 | */ | |
61 | dcb->dccpd_seq = ADD48(dp->dccps_gss, 1); | |
7c657876 | 62 | |
7c657876 ACM |
63 | switch (dcb->dccpd_type) { |
64 | case DCCP_PKT_DATA: | |
65 | set_ack = 0; | |
edc9e819 HX |
66 | /* fall through */ |
67 | case DCCP_PKT_DATAACK: | |
ee1a1592 | 68 | case DCCP_PKT_RESET: |
7c657876 | 69 | break; |
edc9e819 | 70 | |
afe00251 AB |
71 | case DCCP_PKT_REQUEST: |
72 | set_ack = 0; | |
73f18fdb GR |
73 | /* Use ISS on the first (non-retransmitted) Request. */ |
74 | if (icsk->icsk_retransmits == 0) | |
75 | dcb->dccpd_seq = dp->dccps_iss; | |
afe00251 AB |
76 | /* fall through */ |
77 | ||
7c657876 ACM |
78 | case DCCP_PKT_SYNC: |
79 | case DCCP_PKT_SYNCACK: | |
b0d045ca | 80 | ackno = dcb->dccpd_ack_seq; |
edc9e819 HX |
81 | /* fall through */ |
82 | default: | |
83 | /* | |
ee1a1592 GR |
84 | * Set owner/destructor: some skbs are allocated via |
85 | * alloc_skb (e.g. when retransmission may happen). | |
86 | * Only Data, DataAck, and Reset packets should come | |
87 | * through here with skb->sk set. | |
edc9e819 HX |
88 | */ |
89 | WARN_ON(skb->sk); | |
90 | skb_set_owner_w(skb, sk); | |
7c657876 ACM |
91 | break; |
92 | } | |
24117727 | 93 | |
2d0817d1 ACM |
94 | if (dccp_insert_options(sk, skb)) { |
95 | kfree_skb(skb); | |
96 | return -EPROTO; | |
97 | } | |
c9eaf173 | 98 | |
fda0fd6c | 99 | |
7c657876 | 100 | /* Build DCCP header and checksum it. */ |
9b42078e | 101 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 102 | dh->dccph_type = dcb->dccpd_type; |
c720c7e8 ED |
103 | dh->dccph_sport = inet->inet_sport; |
104 | dh->dccph_dport = inet->inet_dport; | |
7c657876 ACM |
105 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; |
106 | dh->dccph_ccval = dcb->dccpd_ccval; | |
6f4e5fff | 107 | dh->dccph_cscov = dp->dccps_pcslen; |
7c657876 ACM |
108 | /* XXX For now we're using only 48 bits sequence numbers */ |
109 | dh->dccph_x = 1; | |
110 | ||
73f18fdb | 111 | dccp_update_gss(sk, dcb->dccpd_seq); |
7c657876 ACM |
112 | dccp_hdr_set_seq(dh, dp->dccps_gss); |
113 | if (set_ack) | |
114 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
115 | ||
116 | switch (dcb->dccpd_type) { | |
117 | case DCCP_PKT_REQUEST: | |
7690af3f | 118 | dccp_hdr_request(skb)->dccph_req_service = |
67e6b629 | 119 | dp->dccps_service; |
73f18fdb GR |
120 | /* |
121 | * Limit Ack window to ISS <= P.ackno <= GSS, so that | |
122 | * only Responses to Requests we sent are considered. | |
123 | */ | |
124 | dp->dccps_awl = dp->dccps_iss; | |
7c657876 ACM |
125 | break; |
126 | case DCCP_PKT_RESET: | |
7690af3f ACM |
127 | dccp_hdr_reset(skb)->dccph_reset_code = |
128 | dcb->dccpd_reset_code; | |
7c657876 ACM |
129 | break; |
130 | } | |
131 | ||
bb296246 | 132 | icsk->icsk_af_ops->send_check(sk, skb); |
7c657876 | 133 | |
7ad07e7c | 134 | if (set_ack) |
7c657876 ACM |
135 | dccp_event_ack_sent(sk); |
136 | ||
137 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
138 | ||
4e15ed4d | 139 | err = icsk->icsk_af_ops->queue_xmit(skb); |
b9df3cb8 | 140 | return net_xmit_eval(err); |
7c657876 ACM |
141 | } |
142 | return -ENOBUFS; | |
143 | } | |
144 | ||
6179983a GR |
145 | /** |
146 | * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits | |
147 | * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), | |
148 | * since the RX CCID is restricted to feedback packets (Acks), which are small | |
149 | * in comparison with the data traffic. A value of 0 means "no current CCMPS". | |
150 | */ | |
151 | static u32 dccp_determine_ccmps(const struct dccp_sock *dp) | |
152 | { | |
153 | const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; | |
154 | ||
155 | if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) | |
156 | return 0; | |
157 | return tx_ccid->ccid_ops->ccid_ccmps; | |
158 | } | |
159 | ||
7c657876 ACM |
160 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
161 | { | |
d83d8461 | 162 | struct inet_connection_sock *icsk = inet_csk(sk); |
7c657876 | 163 | struct dccp_sock *dp = dccp_sk(sk); |
6179983a | 164 | u32 ccmps = dccp_determine_ccmps(dp); |
361a5c1d | 165 | u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; |
7c657876 | 166 | |
6179983a GR |
167 | /* Account for header lengths and IPv4/v6 option overhead */ |
168 | cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + | |
169 | sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); | |
7c657876 ACM |
170 | |
171 | /* | |
361a5c1d GR |
172 | * Leave enough headroom for common DCCP header options. |
173 | * This only considers options which may appear on DCCP-Data packets, as | |
174 | * per table 3 in RFC 4340, 5.8. When running out of space for other | |
175 | * options (eg. Ack Vector which can take up to 255 bytes), it is better | |
176 | * to schedule a separate Ack. Thus we leave headroom for the following: | |
177 | * - 1 byte for Slow Receiver (11.6) | |
178 | * - 6 bytes for Timestamp (13.1) | |
179 | * - 10 bytes for Timestamp Echo (13.3) | |
180 | * - 8 bytes for NDP count (7.7, when activated) | |
181 | * - 6 bytes for Data Checksum (9.3) | |
182 | * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled) | |
7c657876 | 183 | */ |
361a5c1d GR |
184 | cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 + |
185 | (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4); | |
7c657876 ACM |
186 | |
187 | /* And store cached results */ | |
d83d8461 | 188 | icsk->icsk_pmtu_cookie = pmtu; |
6179983a | 189 | dp->dccps_mss_cache = cur_mps; |
7c657876 | 190 | |
6179983a | 191 | return cur_mps; |
7c657876 ACM |
192 | } |
193 | ||
f21e68ca ACM |
194 | EXPORT_SYMBOL_GPL(dccp_sync_mss); |
195 | ||
c530cfb1 ACM |
196 | void dccp_write_space(struct sock *sk) |
197 | { | |
198 | read_lock(&sk->sk_callback_lock); | |
199 | ||
a57de0b4 | 200 | if (sk_has_sleeper(sk)) |
c530cfb1 ACM |
201 | wake_up_interruptible(sk->sk_sleep); |
202 | /* Should agree with poll, otherwise some programs break */ | |
203 | if (sock_writeable(sk)) | |
8d8ad9d7 | 204 | sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
c530cfb1 ACM |
205 | |
206 | read_unlock(&sk->sk_callback_lock); | |
207 | } | |
208 | ||
d6809c12 ACM |
209 | /** |
210 | * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet | |
bc849872 GR |
211 | * @sk: socket to wait for |
212 | * @skb: current skb to pass on for waiting | |
213 | * @delay: sleep timeout in milliseconds (> 0) | |
214 | * This function is called by default when the socket is closed, and | |
215 | * when a non-zero linger time is set on the socket. For consistency | |
d6809c12 | 216 | */ |
bc849872 | 217 | static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) |
d6809c12 ACM |
218 | { |
219 | struct dccp_sock *dp = dccp_sk(sk); | |
220 | DEFINE_WAIT(wait); | |
bc849872 | 221 | unsigned long jiffdelay; |
d6809c12 ACM |
222 | int rc; |
223 | ||
bc849872 GR |
224 | do { |
225 | dccp_pr_debug("delayed send by %d msec\n", delay); | |
226 | jiffdelay = msecs_to_jiffies(delay); | |
227 | ||
d6809c12 ACM |
228 | prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); |
229 | ||
bc849872 GR |
230 | sk->sk_write_pending++; |
231 | release_sock(sk); | |
232 | schedule_timeout(jiffdelay); | |
233 | lock_sock(sk); | |
234 | sk->sk_write_pending--; | |
235 | ||
97e5848d | 236 | if (sk->sk_err) |
d6809c12 | 237 | goto do_error; |
d6809c12 ACM |
238 | if (signal_pending(current)) |
239 | goto do_interrupted; | |
240 | ||
6b57c93d | 241 | rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
bc849872 | 242 | } while ((delay = rc) > 0); |
d6809c12 ACM |
243 | out: |
244 | finish_wait(sk->sk_sleep, &wait); | |
245 | return rc; | |
246 | ||
247 | do_error: | |
248 | rc = -EPIPE; | |
249 | goto out; | |
d6809c12 | 250 | do_interrupted: |
5cc3741d | 251 | rc = -EINTR; |
d6809c12 ACM |
252 | goto out; |
253 | } | |
254 | ||
97e5848d | 255 | void dccp_write_xmit(struct sock *sk, int block) |
27258ee5 | 256 | { |
97e5848d IM |
257 | struct dccp_sock *dp = dccp_sk(sk); |
258 | struct sk_buff *skb; | |
97e5848d IM |
259 | |
260 | while ((skb = skb_peek(&sk->sk_write_queue))) { | |
6b57c93d | 261 | int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
d6809c12 | 262 | |
97e5848d IM |
263 | if (err > 0) { |
264 | if (!block) { | |
265 | sk_reset_timer(sk, &dp->dccps_xmit_timer, | |
266 | msecs_to_jiffies(err)+jiffies); | |
267 | break; | |
5cc3741d | 268 | } else |
bc849872 | 269 | err = dccp_wait_for_ccid(sk, skb, err); |
f6282f4d | 270 | if (err && err != -EINTR) |
59348b19 | 271 | DCCP_BUG("err=%d after dccp_wait_for_ccid", err); |
97e5848d | 272 | } |
27258ee5 | 273 | |
97e5848d IM |
274 | skb_dequeue(&sk->sk_write_queue); |
275 | if (err == 0) { | |
276 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
277 | const int len = skb->len; | |
27258ee5 | 278 | |
97e5848d | 279 | if (sk->sk_state == DCCP_PARTOPEN) { |
86739fb9 GR |
280 | const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; |
281 | /* | |
282 | * See 8.1.5 - Handshake Completion. | |
283 | * | |
284 | * For robustness we resend Confirm options until the client has | |
285 | * entered OPEN. During the initial feature negotiation, the MPS | |
286 | * is smaller than usual, reduced by the Change/Confirm options. | |
287 | */ | |
288 | if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { | |
289 | DCCP_WARN("Payload too large (%d) for featneg.\n", len); | |
290 | dccp_send_ack(sk); | |
291 | dccp_feat_list_purge(&dp->dccps_featneg); | |
292 | } | |
293 | ||
97e5848d IM |
294 | inet_csk_schedule_ack(sk); |
295 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
27258ee5 ACM |
296 | inet_csk(sk)->icsk_rto, |
297 | DCCP_RTO_MAX); | |
97e5848d IM |
298 | dcb->dccpd_type = DCCP_PKT_DATAACK; |
299 | } else if (dccp_ack_pending(sk)) | |
300 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
301 | else | |
302 | dcb->dccpd_type = DCCP_PKT_DATA; | |
303 | ||
304 | err = dccp_transmit_skb(sk, skb); | |
305 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); | |
59348b19 GR |
306 | if (err) |
307 | DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", | |
308 | err); | |
f6282f4d | 309 | } else { |
6626e362 | 310 | dccp_pr_debug("packet discarded due to err=%d\n", err); |
b08d5840 | 311 | kfree_skb(skb); |
f6282f4d | 312 | } |
97e5848d | 313 | } |
27258ee5 ACM |
314 | } |
315 | ||
59435444 GR |
316 | /** |
317 | * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets | |
318 | * There are only four retransmittable packet types in DCCP: | |
319 | * - Request in client-REQUEST state (sec. 8.1.1), | |
320 | * - CloseReq in server-CLOSEREQ state (sec. 8.3), | |
321 | * - Close in node-CLOSING state (sec. 8.3), | |
322 | * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). | |
323 | * This function expects sk->sk_send_head to contain the original skb. | |
324 | */ | |
325 | int dccp_retransmit_skb(struct sock *sk) | |
7c657876 | 326 | { |
59435444 GR |
327 | WARN_ON(sk->sk_send_head == NULL); |
328 | ||
57cca05a | 329 | if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) |
7c657876 ACM |
330 | return -EHOSTUNREACH; /* Routing failure or similar. */ |
331 | ||
59435444 GR |
332 | /* this count is used to distinguish original and retransmitted skb */ |
333 | inet_csk(sk)->icsk_retransmits++; | |
334 | ||
335 | return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); | |
7c657876 ACM |
336 | } |
337 | ||
338 | struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, | |
339 | struct request_sock *req) | |
340 | { | |
341 | struct dccp_hdr *dh; | |
67e6b629 | 342 | struct dccp_request_sock *dreq; |
118b2c95 | 343 | const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
7c657876 ACM |
344 | sizeof(struct dccp_hdr_ext) + |
345 | sizeof(struct dccp_hdr_response); | |
118b2c95 | 346 | struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, |
7c657876 ACM |
347 | GFP_ATOMIC); |
348 | if (skb == NULL) | |
349 | return NULL; | |
350 | ||
351 | /* Reserve space for headers. */ | |
118b2c95 | 352 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 353 | |
adf30907 | 354 | skb_dst_set(skb, dst_clone(dst)); |
7c657876 | 355 | |
67e6b629 | 356 | dreq = dccp_rsk(req); |
e11d9d30 GR |
357 | if (inet_rsk(req)->acked) /* increase ISS upon retransmission */ |
358 | dccp_inc_seqno(&dreq->dreq_iss); | |
7c657876 | 359 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
67e6b629 | 360 | DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; |
2d0817d1 | 361 | |
0c116839 GR |
362 | /* Resolve feature dependencies resulting from choice of CCID */ |
363 | if (dccp_feat_server_ccid_dependencies(dreq)) | |
364 | goto response_failed; | |
365 | ||
366 | if (dccp_insert_options_rsk(dreq, skb)) | |
367 | goto response_failed; | |
7c657876 | 368 | |
09dbc389 | 369 | /* Build and checksum header */ |
9b42078e | 370 | dh = dccp_zeroed_hdr(skb, dccp_header_size); |
7c657876 | 371 | |
944f7502 | 372 | dh->dccph_sport = inet_rsk(req)->loc_port; |
7c657876 | 373 | dh->dccph_dport = inet_rsk(req)->rmt_port; |
7690af3f ACM |
374 | dh->dccph_doff = (dccp_header_size + |
375 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
376 | dh->dccph_type = DCCP_PKT_RESPONSE; |
377 | dh->dccph_x = 1; | |
67e6b629 ACM |
378 | dccp_hdr_set_seq(dh, dreq->dreq_iss); |
379 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr); | |
380 | dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; | |
7c657876 | 381 | |
6f4e5fff GR |
382 | dccp_csum_outgoing(skb); |
383 | ||
e11d9d30 GR |
384 | /* We use `acked' to remember that a Response was already sent. */ |
385 | inet_rsk(req)->acked = 1; | |
7c657876 ACM |
386 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
387 | return skb; | |
0c116839 GR |
388 | response_failed: |
389 | kfree_skb(skb); | |
390 | return NULL; | |
7c657876 ACM |
391 | } |
392 | ||
f21e68ca ACM |
393 | EXPORT_SYMBOL_GPL(dccp_make_response); |
394 | ||
e356d37a | 395 | /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
7630f026 | 396 | struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
e356d37a GR |
397 | { |
398 | struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; | |
399 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); | |
400 | const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + | |
401 | sizeof(struct dccp_hdr_ext) + | |
402 | sizeof(struct dccp_hdr_reset); | |
403 | struct dccp_hdr_reset *dhr; | |
404 | struct sk_buff *skb; | |
405 | ||
7630f026 | 406 | skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
e356d37a GR |
407 | if (skb == NULL) |
408 | return NULL; | |
409 | ||
7630f026 | 410 | skb_reserve(skb, sk->sk_prot->max_header); |
e356d37a GR |
411 | |
412 | /* Swap the send and the receive. */ | |
413 | dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); | |
414 | dh->dccph_type = DCCP_PKT_RESET; | |
415 | dh->dccph_sport = rxdh->dccph_dport; | |
416 | dh->dccph_dport = rxdh->dccph_sport; | |
417 | dh->dccph_doff = dccp_hdr_reset_len / 4; | |
418 | dh->dccph_x = 1; | |
419 | ||
420 | dhr = dccp_hdr_reset(skb); | |
421 | dhr->dccph_reset_code = dcb->dccpd_reset_code; | |
422 | ||
423 | switch (dcb->dccpd_reset_code) { | |
424 | case DCCP_RESET_CODE_PACKET_ERROR: | |
425 | dhr->dccph_reset_data[0] = rxdh->dccph_type; | |
426 | break; | |
427 | case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */ | |
428 | case DCCP_RESET_CODE_MANDATORY_ERROR: | |
429 | memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); | |
430 | break; | |
431 | } | |
432 | /* | |
433 | * From RFC 4340, 8.3.1: | |
434 | * If P.ackno exists, set R.seqno := P.ackno + 1. | |
435 | * Else set R.seqno := 0. | |
436 | */ | |
437 | if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) | |
438 | dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); | |
439 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); | |
440 | ||
441 | dccp_csum_outgoing(skb); | |
442 | return skb; | |
443 | } | |
444 | ||
445 | EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); | |
446 | ||
ee1a1592 | 447 | /* send Reset on established socket, to close or abort the connection */ |
017487d7 ACM |
448 | int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
449 | { | |
ee1a1592 | 450 | struct sk_buff *skb; |
017487d7 ACM |
451 | /* |
452 | * FIXME: what if rebuild_header fails? | |
453 | * Should we be doing a rebuild_header here? | |
454 | */ | |
f53dc67c | 455 | int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
017487d7 | 456 | |
ee1a1592 GR |
457 | if (err != 0) |
458 | return err; | |
459 | ||
460 | skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); | |
461 | if (skb == NULL) | |
462 | return -ENOBUFS; | |
463 | ||
464 | /* Reserve space for headers and prepare control bits. */ | |
465 | skb_reserve(skb, sk->sk_prot->max_header); | |
466 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
467 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
017487d7 | 468 | |
ee1a1592 | 469 | return dccp_transmit_skb(sk, skb); |
017487d7 ACM |
470 | } |
471 | ||
7c657876 ACM |
472 | /* |
473 | * Do all connect socket setups that can be done AF independent. | |
474 | */ | |
475 | static inline void dccp_connect_init(struct sock *sk) | |
476 | { | |
f21e68ca | 477 | struct dccp_sock *dp = dccp_sk(sk); |
7c657876 ACM |
478 | struct dst_entry *dst = __sk_dst_get(sk); |
479 | struct inet_connection_sock *icsk = inet_csk(sk); | |
480 | ||
481 | sk->sk_err = 0; | |
482 | sock_reset_flag(sk, SOCK_DONE); | |
c9eaf173 | 483 | |
7c657876 ACM |
484 | dccp_sync_mss(sk, dst_mtu(dst)); |
485 | ||
73f18fdb | 486 | /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ |
d7f7365f GR |
487 | dp->dccps_gar = dp->dccps_iss; |
488 | ||
7c657876 ACM |
489 | icsk->icsk_retransmits = 0; |
490 | } | |
491 | ||
492 | int dccp_connect(struct sock *sk) | |
493 | { | |
494 | struct sk_buff *skb; | |
495 | struct inet_connection_sock *icsk = inet_csk(sk); | |
496 | ||
9eca0a47 GR |
497 | /* do not connect if feature negotiation setup fails */ |
498 | if (dccp_feat_finalise_settings(dccp_sk(sk))) | |
499 | return -EPROTO; | |
500 | ||
7c657876 ACM |
501 | dccp_connect_init(sk); |
502 | ||
118b2c95 | 503 | skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
7c657876 ACM |
504 | if (unlikely(skb == NULL)) |
505 | return -ENOBUFS; | |
506 | ||
507 | /* Reserve space for headers. */ | |
118b2c95 | 508 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 ACM |
509 | |
510 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
7c657876 | 511 | |
48918a4d | 512 | dccp_skb_entail(sk, skb); |
7c657876 ACM |
513 | dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); |
514 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); | |
515 | ||
516 | /* Timer for repeating the REQUEST until an answer. */ | |
27258ee5 ACM |
517 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
518 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
519 | return 0; |
520 | } | |
521 | ||
f21e68ca ACM |
522 | EXPORT_SYMBOL_GPL(dccp_connect); |
523 | ||
7c657876 ACM |
524 | void dccp_send_ack(struct sock *sk) |
525 | { | |
526 | /* If we have been reset, we may not send again. */ | |
527 | if (sk->sk_state != DCCP_CLOSED) { | |
118b2c95 ACM |
528 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
529 | GFP_ATOMIC); | |
7c657876 ACM |
530 | |
531 | if (skb == NULL) { | |
532 | inet_csk_schedule_ack(sk); | |
533 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
534 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
535 | TCP_DELACK_MAX, | |
536 | DCCP_RTO_MAX); | |
7c657876 ACM |
537 | return; |
538 | } | |
539 | ||
540 | /* Reserve space for headers */ | |
118b2c95 | 541 | skb_reserve(skb, sk->sk_prot->max_header); |
7c657876 | 542 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
7c657876 ACM |
543 | dccp_transmit_skb(sk, skb); |
544 | } | |
545 | } | |
546 | ||
547 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
548 | ||
1e2f0e5e | 549 | #if 0 |
727ecc5f | 550 | /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
7c657876 ACM |
551 | void dccp_send_delayed_ack(struct sock *sk) |
552 | { | |
553 | struct inet_connection_sock *icsk = inet_csk(sk); | |
554 | /* | |
555 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
556 | * with using 2s, and active senders also piggyback the ACK into a | |
557 | * DATAACK packet, so this is really for quiescent senders. | |
558 | */ | |
559 | unsigned long timeout = jiffies + 2 * HZ; | |
560 | ||
561 | /* Use new timeout only if there wasn't a older one earlier. */ | |
562 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
563 | /* If delack timer was blocked or is about to expire, | |
564 | * send ACK now. | |
565 | * | |
566 | * FIXME: check the "about to expire" part | |
567 | */ | |
568 | if (icsk->icsk_ack.blocked) { | |
569 | dccp_send_ack(sk); | |
570 | return; | |
571 | } | |
572 | ||
573 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
574 | timeout = icsk->icsk_ack.timeout; | |
575 | } | |
576 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
577 | icsk->icsk_ack.timeout = timeout; | |
578 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
579 | } | |
1e2f0e5e | 580 | #endif |
7c657876 | 581 | |
b0d045ca | 582 | void dccp_send_sync(struct sock *sk, const u64 ackno, |
e92ae93a | 583 | const enum dccp_pkt_type pkt_type) |
7c657876 ACM |
584 | { |
585 | /* | |
586 | * We are not putting this on the write queue, so | |
587 | * dccp_transmit_skb() will set the ownership to this | |
588 | * sock. | |
589 | */ | |
118b2c95 | 590 | struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
7c657876 | 591 | |
b0d045ca | 592 | if (skb == NULL) { |
7c657876 | 593 | /* FIXME: how to make sure the sync is sent? */ |
b0d045ca | 594 | DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
7c657876 | 595 | return; |
b0d045ca | 596 | } |
7c657876 ACM |
597 | |
598 | /* Reserve space for headers and prepare control bits. */ | |
118b2c95 | 599 | skb_reserve(skb, sk->sk_prot->max_header); |
e92ae93a | 600 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
b0d045ca | 601 | DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
7c657876 | 602 | |
7c657876 ACM |
603 | dccp_transmit_skb(sk, skb); |
604 | } | |
605 | ||
b61fafc4 ACM |
606 | EXPORT_SYMBOL_GPL(dccp_send_sync); |
607 | ||
7690af3f ACM |
608 | /* |
609 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
610 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
611 | * any circumstances. | |
7c657876 | 612 | */ |
7ad07e7c | 613 | void dccp_send_close(struct sock *sk, const int active) |
7c657876 ACM |
614 | { |
615 | struct dccp_sock *dp = dccp_sk(sk); | |
616 | struct sk_buff *skb; | |
7d877f3b | 617 | const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
7c657876 | 618 | |
7ad07e7c ACM |
619 | skb = alloc_skb(sk->sk_prot->max_header, prio); |
620 | if (skb == NULL) | |
621 | return; | |
7c657876 ACM |
622 | |
623 | /* Reserve space for headers and prepare control bits. */ | |
624 | skb_reserve(skb, sk->sk_prot->max_header); | |
b8599d20 GR |
625 | if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
626 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; | |
627 | else | |
628 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; | |
7c657876 | 629 | |
7ad07e7c | 630 | if (active) { |
97e5848d | 631 | dccp_write_xmit(sk, 1); |
48918a4d | 632 | dccp_skb_entail(sk, skb); |
7ad07e7c | 633 | dccp_transmit_skb(sk, skb_clone(skb, prio)); |
92d31920 GR |
634 | /* |
635 | * Retransmission timer for active-close: RFC 4340, 8.3 requires | |
636 | * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ | |
637 | * state can be left. The initial timeout is 2 RTTs. | |
638 | * Since RTT measurement is done by the CCIDs, there is no easy | |
639 | * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 | |
640 | * is too low (200ms); we use a high value to avoid unnecessary | |
641 | * retransmissions when the link RTT is > 0.2 seconds. | |
642 | * FIXME: Let main module sample RTTs and use that instead. | |
643 | */ | |
644 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
645 | DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); | |
7ad07e7c ACM |
646 | } else |
647 | dccp_transmit_skb(sk, skb); | |
7c657876 | 648 | } |