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Cache xtime every call to update_wall_time
[usb.git] / net / dccp / options.c
blob34d536d5f1a1f4bafbd4bdf553b5832d4d5dcceb
1 /*
2 * net/dccp/options.c
3 *
4 * An implementation of the DCCP protocol
5 * Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
6 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
7 * Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14 #include <linux/dccp.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/skbuff.h>
19
20 #include "ackvec.h"
21 #include "ccid.h"
22 #include "dccp.h"
23 #include "feat.h"
24
25 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
26 int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID;
27 int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID;
28 int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO;
29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
30 int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
31
32 void dccp_minisock_init(struct dccp_minisock *dmsk)
33 {
34 dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
35 dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid;
36 dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid;
37 dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio;
38 dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
39 dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count;
40 }
41
42 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
43 {
44 u32 value = 0;
45
46 if (len > 3)
47 value += *bf++ << 24;
48 if (len > 2)
49 value += *bf++ << 16;
50 if (len > 1)
51 value += *bf++ << 8;
52 if (len > 0)
53 value += *bf;
54
55 return value;
56 }
57
58 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
59 {
60 struct dccp_sock *dp = dccp_sk(sk);
61 const struct dccp_hdr *dh = dccp_hdr(skb);
62 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
63 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
64 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
65 unsigned char *opt_ptr = options;
66 const unsigned char *opt_end = (unsigned char *)dh +
67 (dh->dccph_doff * 4);
68 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
69 unsigned char opt, len;
70 unsigned char *value;
71 u32 elapsed_time;
72 int rc;
73 int mandatory = 0;
74
75 memset(opt_recv, 0, sizeof(*opt_recv));
76
77 opt = len = 0;
78 while (opt_ptr != opt_end) {
79 opt = *opt_ptr++;
80 len = 0;
81 value = NULL;
82
83 /* Check if this isn't a single byte option */
84 if (opt > DCCPO_MAX_RESERVED) {
85 if (opt_ptr == opt_end)
86 goto out_invalid_option;
87
88 len = *opt_ptr++;
89 if (len < 3)
90 goto out_invalid_option;
91 /*
92 * Remove the type and len fields, leaving
93 * just the value size
94 */
95 len -= 2;
96 value = opt_ptr;
97 opt_ptr += len;
98
99 if (opt_ptr > opt_end)
100 goto out_invalid_option;
101 }
102
103 switch (opt) {
104 case DCCPO_PADDING:
105 break;
106 case DCCPO_MANDATORY:
107 if (mandatory)
108 goto out_invalid_option;
109 if (pkt_type != DCCP_PKT_DATA)
110 mandatory = 1;
111 break;
112 case DCCPO_NDP_COUNT:
113 if (len > 3)
114 goto out_invalid_option;
115
116 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
117 dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
118 opt_recv->dccpor_ndp);
119 break;
120 case DCCPO_CHANGE_L:
121 /* fall through */
122 case DCCPO_CHANGE_R:
123 if (len < 2)
124 goto out_invalid_option;
125 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
126 len - 1);
127 /*
128 * When there is a change error, change_recv is
129 * responsible for dealing with it. i.e. reply with an
130 * empty confirm.
131 * If the change was mandatory, then we need to die.
132 */
133 if (rc && mandatory)
134 goto out_invalid_option;
135 break;
136 case DCCPO_CONFIRM_L:
137 /* fall through */
138 case DCCPO_CONFIRM_R:
139 if (len < 2)
140 goto out_invalid_option;
141 if (dccp_feat_confirm_recv(sk, opt, *value,
142 value + 1, len - 1))
143 goto out_invalid_option;
144 break;
145 case DCCPO_ACK_VECTOR_0:
146 case DCCPO_ACK_VECTOR_1:
147 if (pkt_type == DCCP_PKT_DATA)
148 break;
149
150 if (dccp_msk(sk)->dccpms_send_ack_vector &&
151 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
152 goto out_invalid_option;
153 break;
154 case DCCPO_TIMESTAMP:
155 if (len != 4)
156 goto out_invalid_option;
157
158 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
159
160 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
161 dccp_timestamp(sk, &dp->dccps_timestamp_time);
162
163 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
164 dccp_role(sk), opt_recv->dccpor_timestamp,
165 (unsigned long long)
166 DCCP_SKB_CB(skb)->dccpd_ack_seq);
167 break;
168 case DCCPO_TIMESTAMP_ECHO:
169 if (len != 4 && len != 6 && len != 8)
170 goto out_invalid_option;
171
172 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
173
174 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
175 "ackno=%llu", dccp_role(sk),
176 opt_recv->dccpor_timestamp_echo,
177 len + 2,
178 (unsigned long long)
179 DCCP_SKB_CB(skb)->dccpd_ack_seq);
180
181
182 if (len == 4) {
183 dccp_pr_debug_cat("\n");
184 break;
185 }
186
187 if (len == 6)
188 elapsed_time = ntohs(*(__be16 *)(value + 4));
189 else
190 elapsed_time = ntohl(*(__be32 *)(value + 4));
191
192 dccp_pr_debug_cat(", ELAPSED_TIME=%d\n", elapsed_time);
193
194 /* Give precedence to the biggest ELAPSED_TIME */
195 if (elapsed_time > opt_recv->dccpor_elapsed_time)
196 opt_recv->dccpor_elapsed_time = elapsed_time;
197 break;
198 case DCCPO_ELAPSED_TIME:
199 if (len != 2 && len != 4)
200 goto out_invalid_option;
201
202 if (pkt_type == DCCP_PKT_DATA)
203 continue;
204
205 if (len == 2)
206 elapsed_time = ntohs(*(__be16 *)value);
207 else
208 elapsed_time = ntohl(*(__be32 *)value);
209
210 if (elapsed_time > opt_recv->dccpor_elapsed_time)
211 opt_recv->dccpor_elapsed_time = elapsed_time;
212
213 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
214 dccp_role(sk), elapsed_time);
215 break;
216 /*
217 * From RFC 4340, sec. 10.3:
218 *
219 * Option numbers 128 through 191 are for
220 * options sent from the HC-Sender to the
221 * HC-Receiver; option numbers 192 through 255
222 * are for options sent from the HC-Receiver to
223 * the HC-Sender.
224 */
225 case 128 ... 191: {
226 const u16 idx = value - options;
227
228 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
229 opt, len, idx,
230 value) != 0)
231 goto out_invalid_option;
232 }
233 break;
234 case 192 ... 255: {
235 const u16 idx = value - options;
236
237 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
238 opt, len, idx,
239 value) != 0)
240 goto out_invalid_option;
241 }
242 break;
243 default:
244 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
245 "implemented, ignoring", sk, opt, len);
246 break;
247 }
248
249 if (opt != DCCPO_MANDATORY)
250 mandatory = 0;
251 }
252
253 /* mandatory was the last byte in option list -> reset connection */
254 if (mandatory)
255 goto out_invalid_option;
256
257 return 0;
258
259 out_invalid_option:
260 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
261 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
262 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
263 return -1;
264 }
265
266 EXPORT_SYMBOL_GPL(dccp_parse_options);
267
268 static void dccp_encode_value_var(const u32 value, unsigned char *to,
269 const unsigned int len)
270 {
271 if (len > 3)
272 *to++ = (value & 0xFF000000) >> 24;
273 if (len > 2)
274 *to++ = (value & 0xFF0000) >> 16;
275 if (len > 1)
276 *to++ = (value & 0xFF00) >> 8;
277 if (len > 0)
278 *to++ = (value & 0xFF);
279 }
280
281 static inline int dccp_ndp_len(const int ndp)
282 {
283 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
284 }
285
286 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
287 const unsigned char option,
288 const void *value, const unsigned char len)
289 {
290 unsigned char *to;
291
292 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
293 return -1;
294
295 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
296
297 to = skb_push(skb, len + 2);
298 *to++ = option;
299 *to++ = len + 2;
300
301 memcpy(to, value, len);
302 return 0;
303 }
304
305 EXPORT_SYMBOL_GPL(dccp_insert_option);
306
307 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
308 {
309 struct dccp_sock *dp = dccp_sk(sk);
310 int ndp = dp->dccps_ndp_count;
311
312 if (dccp_non_data_packet(skb))
313 ++dp->dccps_ndp_count;
314 else
315 dp->dccps_ndp_count = 0;
316
317 if (ndp > 0) {
318 unsigned char *ptr;
319 const int ndp_len = dccp_ndp_len(ndp);
320 const int len = ndp_len + 2;
321
322 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
323 return -1;
324
325 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
326
327 ptr = skb_push(skb, len);
328 *ptr++ = DCCPO_NDP_COUNT;
329 *ptr++ = len;
330 dccp_encode_value_var(ndp, ptr, ndp_len);
331 }
332
333 return 0;
334 }
335
336 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
337 {
338 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
339 }
340
341 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
342 u32 elapsed_time)
343 {
344 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
345 const int len = 2 + elapsed_time_len;
346 unsigned char *to;
347
348 if (elapsed_time_len == 0)
349 return 0;
350
351 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
352 return -1;
353
354 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
355
356 to = skb_push(skb, len);
357 *to++ = DCCPO_ELAPSED_TIME;
358 *to++ = len;
359
360 if (elapsed_time_len == 2) {
361 const __be16 var16 = htons((u16)elapsed_time);
362 memcpy(to, &var16, 2);
363 } else {
364 const __be32 var32 = htonl(elapsed_time);
365 memcpy(to, &var32, 4);
366 }
367
368 return 0;
369 }
370
371 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
372
373 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
374 {
375 const struct dccp_sock *dp = dccp_sk(sk);
376
377 do_gettimeofday(tv);
378 tv->tv_sec -= dp->dccps_epoch.tv_sec;
379 tv->tv_usec -= dp->dccps_epoch.tv_usec;
380
381 while (tv->tv_usec < 0) {
382 tv->tv_sec--;
383 tv->tv_usec += USEC_PER_SEC;
384 }
385 }
386
387 EXPORT_SYMBOL_GPL(dccp_timestamp);
388
389 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
390 {
391 struct timeval tv;
392 __be32 now;
393
394 dccp_timestamp(sk, &tv);
395 now = htonl(timeval_usecs(&tv) / 10);
396 /* yes this will overflow but that is the point as we want a
397 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
398
399 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
400 }
401
402 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
403
404 static int dccp_insert_option_timestamp_echo(struct sock *sk,
405 struct sk_buff *skb)
406 {
407 struct dccp_sock *dp = dccp_sk(sk);
408 struct timeval now;
409 __be32 tstamp_echo;
410 u32 elapsed_time;
411 int len, elapsed_time_len;
412 unsigned char *to;
413
414 dccp_timestamp(sk, &now);
415 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
416 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
417 len = 6 + elapsed_time_len;
418
419 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
420 return -1;
421
422 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
423
424 to = skb_push(skb, len);
425 *to++ = DCCPO_TIMESTAMP_ECHO;
426 *to++ = len;
427
428 tstamp_echo = htonl(dp->dccps_timestamp_echo);
429 memcpy(to, &tstamp_echo, 4);
430 to += 4;
431
432 if (elapsed_time_len == 2) {
433 const __be16 var16 = htons((u16)elapsed_time);
434 memcpy(to, &var16, 2);
435 } else if (elapsed_time_len == 4) {
436 const __be32 var32 = htonl(elapsed_time);
437 memcpy(to, &var32, 4);
438 }
439
440 dp->dccps_timestamp_echo = 0;
441 dp->dccps_timestamp_time.tv_sec = 0;
442 dp->dccps_timestamp_time.tv_usec = 0;
443 return 0;
444 }
445
446 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
447 u8 *val, u8 len)
448 {
449 u8 *to;
450
451 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
452 DCCP_WARN("packet too small for feature %d option!\n", feat);
453 return -1;
454 }
455
456 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
457
458 to = skb_push(skb, len + 3);
459 *to++ = type;
460 *to++ = len + 3;
461 *to++ = feat;
462
463 if (len)
464 memcpy(to, val, len);
465
466 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
467 dccp_feat_typename(type),
468 dccp_feat_name(feat), feat, len);
469 return 0;
470 }
471
472 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
473 {
474 struct dccp_sock *dp = dccp_sk(sk);
475 struct dccp_minisock *dmsk = dccp_msk(sk);
476 struct dccp_opt_pend *opt, *next;
477 int change = 0;
478
479 /* confirm any options [NN opts] */
480 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
481 dccp_insert_feat_opt(skb, opt->dccpop_type,
482 opt->dccpop_feat, opt->dccpop_val,
483 opt->dccpop_len);
484 /* fear empty confirms */
485 if (opt->dccpop_val)
486 kfree(opt->dccpop_val);
487 kfree(opt);
488 }
489 INIT_LIST_HEAD(&dmsk->dccpms_conf);
490
491 /* see which features we need to send */
492 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
493 /* see if we need to send any confirm */
494 if (opt->dccpop_sc) {
495 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
496 opt->dccpop_feat,
497 opt->dccpop_sc->dccpoc_val,
498 opt->dccpop_sc->dccpoc_len);
499
500 BUG_ON(!opt->dccpop_sc->dccpoc_val);
501 kfree(opt->dccpop_sc->dccpoc_val);
502 kfree(opt->dccpop_sc);
503 opt->dccpop_sc = NULL;
504 }
505
506 /* any option not confirmed, re-send it */
507 if (!opt->dccpop_conf) {
508 dccp_insert_feat_opt(skb, opt->dccpop_type,
509 opt->dccpop_feat, opt->dccpop_val,
510 opt->dccpop_len);
511 change++;
512 }
513 }
514
515 /* Retransmit timer.
516 * If this is the master listening sock, we don't set a timer on it. It
517 * should be fine because if the dude doesn't receive our RESPONSE
518 * [which will contain the CHANGE] he will send another REQUEST which
519 * will "retrnasmit" the change.
520 */
521 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
522 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
523
524 /* XXX don't reset the timer on re-transmissions. I.e. reset it
525 * only when sending new stuff i guess. Currently the timer
526 * never backs off because on re-transmission it just resets it!
527 */
528 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
529 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
530 }
531
532 return 0;
533 }
534
535 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
536 {
537 struct dccp_sock *dp = dccp_sk(sk);
538 struct dccp_minisock *dmsk = dccp_msk(sk);
539
540 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
541
542 if (dmsk->dccpms_send_ndp_count &&
543 dccp_insert_option_ndp(sk, skb))
544 return -1;
545
546 if (!dccp_packet_without_ack(skb)) {
547 if (dmsk->dccpms_send_ack_vector &&
548 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
549 dccp_insert_option_ackvec(sk, skb))
550 return -1;
551
552 if (dp->dccps_timestamp_echo != 0 &&
553 dccp_insert_option_timestamp_echo(sk, skb))
554 return -1;
555 }
556
557 if (dp->dccps_hc_rx_insert_options) {
558 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
559 return -1;
560 dp->dccps_hc_rx_insert_options = 0;
561 }
562
563 /* Feature negotiation */
564 /* Data packets can't do feat negotiation */
565 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
566 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
567 dccp_insert_options_feat(sk, skb))
568 return -1;
569
570 /*
571 * Obtain RTT sample from Request/Response exchange.
572 * This is currently used in CCID 3 initialisation.
573 */
574 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
575 dccp_insert_option_timestamp(sk, skb))
576 return -1;
577
578 /* XXX: insert other options when appropriate */
579
580 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
581 /* The length of all options has to be a multiple of 4 */
582 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
583
584 if (padding != 0) {
585 padding = 4 - padding;
586 memset(skb_push(skb, padding), 0, padding);
587 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
588 }
589 }
590
591 return 0;
592 }
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