]>
Commit | Line | Data |
---|---|---|
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 | ||
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 | ||
27 | /* | |
28 | * All SKB's seen here are completely headerless. It is our | |
29 | * job to build the DCCP header, and pass the packet down to | |
30 | * IP so it can do the same plus pass the packet off to the | |
31 | * device. | |
32 | */ | |
33 | int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) | |
34 | { | |
35 | if (likely(skb != NULL)) { | |
36 | const struct inet_sock *inet = inet_sk(sk); | |
37 | struct dccp_sock *dp = dccp_sk(sk); | |
38 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
39 | struct dccp_hdr *dh; | |
40 | /* XXX For now we're using only 48 bits sequence numbers */ | |
41 | const int dccp_header_size = sizeof(*dh) + | |
42 | sizeof(struct dccp_hdr_ext) + | |
7690af3f | 43 | dccp_packet_hdr_len(dcb->dccpd_type); |
7c657876 ACM |
44 | int err, set_ack = 1; |
45 | u64 ackno = dp->dccps_gsr; | |
46 | ||
7c657876 ACM |
47 | dccp_inc_seqno(&dp->dccps_gss); |
48 | ||
7c657876 ACM |
49 | switch (dcb->dccpd_type) { |
50 | case DCCP_PKT_DATA: | |
51 | set_ack = 0; | |
52 | break; | |
53 | case DCCP_PKT_SYNC: | |
54 | case DCCP_PKT_SYNCACK: | |
55 | ackno = dcb->dccpd_seq; | |
56 | break; | |
57 | } | |
24117727 ACM |
58 | |
59 | dcb->dccpd_seq = dp->dccps_gss; | |
60 | dccp_insert_options(sk, skb); | |
7c657876 ACM |
61 | |
62 | skb->h.raw = skb_push(skb, dccp_header_size); | |
63 | dh = dccp_hdr(skb); | |
7690af3f ACM |
64 | /* |
65 | * Data packets are not cloned as they are never retransmitted | |
66 | */ | |
7c657876 ACM |
67 | if (skb_cloned(skb)) |
68 | skb_set_owner_w(skb, sk); | |
69 | ||
70 | /* Build DCCP header and checksum it. */ | |
71 | memset(dh, 0, dccp_header_size); | |
72 | dh->dccph_type = dcb->dccpd_type; | |
73 | dh->dccph_sport = inet->sport; | |
74 | dh->dccph_dport = inet->dport; | |
75 | dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; | |
76 | dh->dccph_ccval = dcb->dccpd_ccval; | |
77 | /* XXX For now we're using only 48 bits sequence numbers */ | |
78 | dh->dccph_x = 1; | |
79 | ||
80 | dp->dccps_awh = dp->dccps_gss; | |
81 | dccp_hdr_set_seq(dh, dp->dccps_gss); | |
82 | if (set_ack) | |
83 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); | |
84 | ||
85 | switch (dcb->dccpd_type) { | |
86 | case DCCP_PKT_REQUEST: | |
7690af3f ACM |
87 | dccp_hdr_request(skb)->dccph_req_service = |
88 | dcb->dccpd_service; | |
7c657876 ACM |
89 | break; |
90 | case DCCP_PKT_RESET: | |
7690af3f ACM |
91 | dccp_hdr_reset(skb)->dccph_reset_code = |
92 | dcb->dccpd_reset_code; | |
7c657876 ACM |
93 | break; |
94 | } | |
95 | ||
95b81ef7 YN |
96 | dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr, |
97 | inet->daddr); | |
7c657876 ACM |
98 | |
99 | if (dcb->dccpd_type == DCCP_PKT_ACK || | |
100 | dcb->dccpd_type == DCCP_PKT_DATAACK) | |
101 | dccp_event_ack_sent(sk); | |
102 | ||
103 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
104 | ||
105 | err = ip_queue_xmit(skb, 0); | |
106 | if (err <= 0) | |
107 | return err; | |
108 | ||
109 | /* NET_XMIT_CN is special. It does not guarantee, | |
110 | * that this packet is lost. It tells that device | |
111 | * is about to start to drop packets or already | |
112 | * drops some packets of the same priority and | |
113 | * invokes us to send less aggressively. | |
114 | */ | |
115 | return err == NET_XMIT_CN ? 0 : err; | |
116 | } | |
117 | return -ENOBUFS; | |
118 | } | |
119 | ||
120 | unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) | |
121 | { | |
122 | struct dccp_sock *dp = dccp_sk(sk); | |
123 | int mss_now; | |
124 | ||
125 | /* | |
7690af3f ACM |
126 | * FIXME: we really should be using the af_specific thing to support |
127 | * IPv6. | |
128 | * mss_now = pmtu - tp->af_specific->net_header_len - | |
129 | * sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext); | |
7c657876 | 130 | */ |
7690af3f ACM |
131 | mss_now = pmtu - sizeof(struct iphdr) - sizeof(struct dccp_hdr) - |
132 | sizeof(struct dccp_hdr_ext); | |
7c657876 ACM |
133 | |
134 | /* Now subtract optional transport overhead */ | |
135 | mss_now -= dp->dccps_ext_header_len; | |
136 | ||
137 | /* | |
138 | * FIXME: this should come from the CCID infrastructure, where, say, | |
139 | * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets | |
140 | * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED | |
141 | * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to | |
142 | * make it a multiple of 4 | |
143 | */ | |
144 | ||
145 | mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4; | |
146 | ||
147 | /* And store cached results */ | |
148 | dp->dccps_pmtu_cookie = pmtu; | |
149 | dp->dccps_mss_cache = mss_now; | |
150 | ||
151 | return mss_now; | |
152 | } | |
153 | ||
27258ee5 ACM |
154 | int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, const int len) |
155 | { | |
156 | const struct dccp_sock *dp = dccp_sk(sk); | |
157 | int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb, len); | |
158 | ||
159 | if (err == 0) { | |
160 | const struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts; | |
161 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); | |
162 | ||
163 | if (sk->sk_state == DCCP_PARTOPEN) { | |
164 | /* See 8.1.5. Handshake Completion */ | |
165 | inet_csk_schedule_ack(sk); | |
166 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
167 | inet_csk(sk)->icsk_rto, | |
168 | DCCP_RTO_MAX); | |
169 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
170 | /* | |
171 | * FIXME: we really should have a | |
172 | * dccps_ack_pending or use icsk. | |
173 | */ | |
174 | } else if (inet_csk_ack_scheduled(sk) || | |
175 | (dp->dccps_options.dccpo_send_ack_vector && | |
176 | ap->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1 && | |
177 | ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)) | |
178 | dcb->dccpd_type = DCCP_PKT_DATAACK; | |
179 | else | |
180 | dcb->dccpd_type = DCCP_PKT_DATA; | |
181 | ||
182 | err = dccp_transmit_skb(sk, skb); | |
183 | ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); | |
184 | } | |
185 | ||
186 | return err; | |
187 | } | |
188 | ||
7c657876 ACM |
189 | int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb) |
190 | { | |
191 | if (inet_sk_rebuild_header(sk) != 0) | |
192 | return -EHOSTUNREACH; /* Routing failure or similar. */ | |
193 | ||
194 | return dccp_transmit_skb(sk, (skb_cloned(skb) ? | |
195 | pskb_copy(skb, GFP_ATOMIC): | |
196 | skb_clone(skb, GFP_ATOMIC))); | |
197 | } | |
198 | ||
199 | struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, | |
200 | struct request_sock *req) | |
201 | { | |
202 | struct dccp_hdr *dh; | |
203 | const int dccp_header_size = sizeof(struct dccp_hdr) + | |
204 | sizeof(struct dccp_hdr_ext) + | |
205 | sizeof(struct dccp_hdr_response); | |
206 | struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN + | |
207 | dccp_header_size, 1, | |
208 | GFP_ATOMIC); | |
209 | if (skb == NULL) | |
210 | return NULL; | |
211 | ||
212 | /* Reserve space for headers. */ | |
213 | skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size); | |
214 | ||
215 | skb->dst = dst_clone(dst); | |
216 | skb->csum = 0; | |
217 | ||
218 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; | |
219 | DCCP_SKB_CB(skb)->dccpd_seq = dccp_rsk(req)->dreq_iss; | |
220 | dccp_insert_options(sk, skb); | |
221 | ||
222 | skb->h.raw = skb_push(skb, dccp_header_size); | |
223 | ||
224 | dh = dccp_hdr(skb); | |
225 | memset(dh, 0, dccp_header_size); | |
226 | ||
227 | dh->dccph_sport = inet_sk(sk)->sport; | |
228 | dh->dccph_dport = inet_rsk(req)->rmt_port; | |
7690af3f ACM |
229 | dh->dccph_doff = (dccp_header_size + |
230 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
231 | dh->dccph_type = DCCP_PKT_RESPONSE; |
232 | dh->dccph_x = 1; | |
233 | dccp_hdr_set_seq(dh, dccp_rsk(req)->dreq_iss); | |
234 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dccp_rsk(req)->dreq_isr); | |
235 | ||
95b81ef7 YN |
236 | dh->dccph_checksum = dccp_v4_checksum(skb, inet_rsk(req)->loc_addr, |
237 | inet_rsk(req)->rmt_addr); | |
7c657876 ACM |
238 | |
239 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
240 | return skb; | |
241 | } | |
242 | ||
243 | struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst, | |
244 | const enum dccp_reset_codes code) | |
245 | ||
246 | { | |
247 | struct dccp_hdr *dh; | |
248 | struct dccp_sock *dp = dccp_sk(sk); | |
249 | const int dccp_header_size = sizeof(struct dccp_hdr) + | |
250 | sizeof(struct dccp_hdr_ext) + | |
251 | sizeof(struct dccp_hdr_reset); | |
252 | struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN + | |
253 | dccp_header_size, 1, | |
254 | GFP_ATOMIC); | |
255 | if (skb == NULL) | |
256 | return NULL; | |
257 | ||
258 | /* Reserve space for headers. */ | |
259 | skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size); | |
260 | ||
261 | skb->dst = dst_clone(dst); | |
262 | skb->csum = 0; | |
263 | ||
264 | dccp_inc_seqno(&dp->dccps_gss); | |
265 | ||
266 | DCCP_SKB_CB(skb)->dccpd_reset_code = code; | |
267 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; | |
268 | DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss; | |
269 | dccp_insert_options(sk, skb); | |
270 | ||
271 | skb->h.raw = skb_push(skb, dccp_header_size); | |
272 | ||
273 | dh = dccp_hdr(skb); | |
274 | memset(dh, 0, dccp_header_size); | |
275 | ||
276 | dh->dccph_sport = inet_sk(sk)->sport; | |
277 | dh->dccph_dport = inet_sk(sk)->dport; | |
7690af3f ACM |
278 | dh->dccph_doff = (dccp_header_size + |
279 | DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; | |
7c657876 ACM |
280 | dh->dccph_type = DCCP_PKT_RESET; |
281 | dh->dccph_x = 1; | |
282 | dccp_hdr_set_seq(dh, dp->dccps_gss); | |
283 | dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr); | |
284 | ||
285 | dccp_hdr_reset(skb)->dccph_reset_code = code; | |
286 | ||
95b81ef7 YN |
287 | dh->dccph_checksum = dccp_v4_checksum(skb, inet_sk(sk)->saddr, |
288 | inet_sk(sk)->daddr); | |
7c657876 ACM |
289 | |
290 | DCCP_INC_STATS(DCCP_MIB_OUTSEGS); | |
291 | return skb; | |
292 | } | |
293 | ||
294 | /* | |
295 | * Do all connect socket setups that can be done AF independent. | |
296 | */ | |
297 | static inline void dccp_connect_init(struct sock *sk) | |
298 | { | |
299 | struct dst_entry *dst = __sk_dst_get(sk); | |
300 | struct inet_connection_sock *icsk = inet_csk(sk); | |
301 | ||
302 | sk->sk_err = 0; | |
303 | sock_reset_flag(sk, SOCK_DONE); | |
304 | ||
305 | dccp_sync_mss(sk, dst_mtu(dst)); | |
306 | ||
307 | /* | |
308 | * FIXME: set dp->{dccps_swh,dccps_swl}, with | |
309 | * something like dccp_inc_seq | |
310 | */ | |
311 | ||
312 | icsk->icsk_retransmits = 0; | |
313 | } | |
314 | ||
315 | int dccp_connect(struct sock *sk) | |
316 | { | |
317 | struct sk_buff *skb; | |
318 | struct inet_connection_sock *icsk = inet_csk(sk); | |
319 | ||
320 | dccp_connect_init(sk); | |
321 | ||
322 | skb = alloc_skb(MAX_DCCP_HEADER + 15, sk->sk_allocation); | |
323 | if (unlikely(skb == NULL)) | |
324 | return -ENOBUFS; | |
325 | ||
326 | /* Reserve space for headers. */ | |
327 | skb_reserve(skb, MAX_DCCP_HEADER); | |
328 | ||
329 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; | |
330 | /* FIXME: set service to something meaningful, coming | |
331 | * from userspace*/ | |
332 | DCCP_SKB_CB(skb)->dccpd_service = 0; | |
333 | skb->csum = 0; | |
334 | skb_set_owner_w(skb, sk); | |
335 | ||
336 | BUG_TRAP(sk->sk_send_head == NULL); | |
337 | sk->sk_send_head = skb; | |
338 | dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); | |
339 | DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); | |
340 | ||
341 | /* Timer for repeating the REQUEST until an answer. */ | |
27258ee5 ACM |
342 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
343 | icsk->icsk_rto, DCCP_RTO_MAX); | |
7c657876 ACM |
344 | return 0; |
345 | } | |
346 | ||
347 | void dccp_send_ack(struct sock *sk) | |
348 | { | |
349 | /* If we have been reset, we may not send again. */ | |
350 | if (sk->sk_state != DCCP_CLOSED) { | |
351 | struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC); | |
352 | ||
353 | if (skb == NULL) { | |
354 | inet_csk_schedule_ack(sk); | |
355 | inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; | |
7690af3f ACM |
356 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
357 | TCP_DELACK_MAX, | |
358 | DCCP_RTO_MAX); | |
7c657876 ACM |
359 | return; |
360 | } | |
361 | ||
362 | /* Reserve space for headers */ | |
363 | skb_reserve(skb, MAX_DCCP_HEADER); | |
364 | skb->csum = 0; | |
365 | DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; | |
366 | skb_set_owner_w(skb, sk); | |
367 | dccp_transmit_skb(sk, skb); | |
368 | } | |
369 | } | |
370 | ||
371 | EXPORT_SYMBOL_GPL(dccp_send_ack); | |
372 | ||
373 | void dccp_send_delayed_ack(struct sock *sk) | |
374 | { | |
375 | struct inet_connection_sock *icsk = inet_csk(sk); | |
376 | /* | |
377 | * FIXME: tune this timer. elapsed time fixes the skew, so no problem | |
378 | * with using 2s, and active senders also piggyback the ACK into a | |
379 | * DATAACK packet, so this is really for quiescent senders. | |
380 | */ | |
381 | unsigned long timeout = jiffies + 2 * HZ; | |
382 | ||
383 | /* Use new timeout only if there wasn't a older one earlier. */ | |
384 | if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { | |
385 | /* If delack timer was blocked or is about to expire, | |
386 | * send ACK now. | |
387 | * | |
388 | * FIXME: check the "about to expire" part | |
389 | */ | |
390 | if (icsk->icsk_ack.blocked) { | |
391 | dccp_send_ack(sk); | |
392 | return; | |
393 | } | |
394 | ||
395 | if (!time_before(timeout, icsk->icsk_ack.timeout)) | |
396 | timeout = icsk->icsk_ack.timeout; | |
397 | } | |
398 | icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; | |
399 | icsk->icsk_ack.timeout = timeout; | |
400 | sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); | |
401 | } | |
402 | ||
e92ae93a ACM |
403 | void dccp_send_sync(struct sock *sk, const u64 seq, |
404 | const enum dccp_pkt_type pkt_type) | |
7c657876 ACM |
405 | { |
406 | /* | |
407 | * We are not putting this on the write queue, so | |
408 | * dccp_transmit_skb() will set the ownership to this | |
409 | * sock. | |
410 | */ | |
411 | struct sk_buff *skb = alloc_skb(MAX_DCCP_HEADER, GFP_ATOMIC); | |
412 | ||
413 | if (skb == NULL) | |
414 | /* FIXME: how to make sure the sync is sent? */ | |
415 | return; | |
416 | ||
417 | /* Reserve space for headers and prepare control bits. */ | |
418 | skb_reserve(skb, MAX_DCCP_HEADER); | |
419 | skb->csum = 0; | |
e92ae93a | 420 | DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
7c657876 ACM |
421 | DCCP_SKB_CB(skb)->dccpd_seq = seq; |
422 | ||
423 | skb_set_owner_w(skb, sk); | |
424 | dccp_transmit_skb(sk, skb); | |
425 | } | |
426 | ||
7690af3f ACM |
427 | /* |
428 | * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This | |
429 | * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under | |
430 | * any circumstances. | |
7c657876 ACM |
431 | */ |
432 | void dccp_send_close(struct sock *sk) | |
433 | { | |
434 | struct dccp_sock *dp = dccp_sk(sk); | |
435 | struct sk_buff *skb; | |
436 | ||
437 | /* Socket is locked, keep trying until memory is available. */ | |
438 | for (;;) { | |
439 | skb = alloc_skb(sk->sk_prot->max_header, GFP_KERNEL); | |
440 | if (skb != NULL) | |
441 | break; | |
442 | yield(); | |
443 | } | |
444 | ||
445 | /* Reserve space for headers and prepare control bits. */ | |
446 | skb_reserve(skb, sk->sk_prot->max_header); | |
447 | skb->csum = 0; | |
7690af3f ACM |
448 | DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ? |
449 | DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ; | |
7c657876 ACM |
450 | |
451 | skb_set_owner_w(skb, sk); | |
452 | dccp_transmit_skb(sk, skb); | |
453 | ||
454 | ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk); | |
455 | ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk); | |
456 | } |