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[IRDA] sem2mutex: drivers/net/irda
[linux-2.6/mini2440.git] / net / dccp / options.c
blobda1676016484f6b32eefc14fede197b55ed99ab5
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 <iam4@cs.waikato.ac.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/config.h>
15 #include <linux/dccp.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/skbuff.h>
20
21 #include "ackvec.h"
22 #include "ccid.h"
23 #include "dccp.h"
24 #include "feat.h"
25
26 int dccp_feat_default_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
27 int dccp_feat_default_rx_ccid = DCCPF_INITIAL_CCID;
28 int dccp_feat_default_tx_ccid = DCCPF_INITIAL_CCID;
29 int dccp_feat_default_ack_ratio = DCCPF_INITIAL_ACK_RATIO;
30 int dccp_feat_default_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
31 int dccp_feat_default_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
32
33 void dccp_options_init(struct dccp_options *dccpo)
34 {
35 dccpo->dccpo_sequence_window = dccp_feat_default_sequence_window;
36 dccpo->dccpo_rx_ccid = dccp_feat_default_rx_ccid;
37 dccpo->dccpo_tx_ccid = dccp_feat_default_tx_ccid;
38 dccpo->dccpo_ack_ratio = dccp_feat_default_ack_ratio;
39 dccpo->dccpo_send_ack_vector = dccp_feat_default_send_ack_vector;
40 dccpo->dccpo_send_ndp_count = dccp_feat_default_send_ndp_count;
41 }
42
43 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
44 {
45 u32 value = 0;
46
47 if (len > 3)
48 value += *bf++ << 24;
49 if (len > 2)
50 value += *bf++ << 16;
51 if (len > 1)
52 value += *bf++ << 8;
53 if (len > 0)
54 value += *bf;
55
56 return value;
57 }
58
59 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
60 {
61 struct dccp_sock *dp = dccp_sk(sk);
62 #ifdef CONFIG_IP_DCCP_DEBUG
63 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
64 "CLIENT rx opt: " : "server rx opt: ";
65 #endif
66 const struct dccp_hdr *dh = dccp_hdr(skb);
67 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
68 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
69 unsigned char *opt_ptr = options;
70 const unsigned char *opt_end = (unsigned char *)dh +
71 (dh->dccph_doff * 4);
72 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
73 unsigned char opt, len;
74 unsigned char *value;
75 u32 elapsed_time;
76 int rc;
77 int mandatory = 0;
78
79 memset(opt_recv, 0, sizeof(*opt_recv));
80
81 while (opt_ptr != opt_end) {
82 opt = *opt_ptr++;
83 len = 0;
84 value = NULL;
85
86 /* Check if this isn't a single byte option */
87 if (opt > DCCPO_MAX_RESERVED) {
88 if (opt_ptr == opt_end)
89 goto out_invalid_option;
90
91 len = *opt_ptr++;
92 if (len < 3)
93 goto out_invalid_option;
94 /*
95 * Remove the type and len fields, leaving
96 * just the value size
97 */
98 len -= 2;
99 value = opt_ptr;
100 opt_ptr += len;
101
102 if (opt_ptr > opt_end)
103 goto out_invalid_option;
104 }
105
106 switch (opt) {
107 case DCCPO_PADDING:
108 break;
109 case DCCPO_MANDATORY:
110 if (mandatory)
111 goto out_invalid_option;
112 if (pkt_type != DCCP_PKT_DATA)
113 mandatory = 1;
114 break;
115 case DCCPO_NDP_COUNT:
116 if (len > 3)
117 goto out_invalid_option;
118
119 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
120 dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
121 opt_recv->dccpor_ndp);
122 break;
123 case DCCPO_CHANGE_L:
124 /* fall through */
125 case DCCPO_CHANGE_R:
126 if (len < 2)
127 goto out_invalid_option;
128 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
129 len - 1);
130 /*
131 * When there is a change error, change_recv is
132 * responsible for dealing with it. i.e. reply with an
133 * empty confirm.
134 * If the change was mandatory, then we need to die.
135 */
136 if (rc && mandatory)
137 goto out_invalid_option;
138 break;
139 case DCCPO_CONFIRM_L:
140 /* fall through */
141 case DCCPO_CONFIRM_R:
142 if (len < 2)
143 goto out_invalid_option;
144 if (dccp_feat_confirm_recv(sk, opt, *value,
145 value + 1, len - 1))
146 goto out_invalid_option;
147 break;
148 case DCCPO_ACK_VECTOR_0:
149 case DCCPO_ACK_VECTOR_1:
150 if (pkt_type == DCCP_PKT_DATA)
151 break;
152
153 if (dp->dccps_options.dccpo_send_ack_vector &&
154 dccp_ackvec_parse(sk, skb, opt, value, len))
155 goto out_invalid_option;
156 break;
157 case DCCPO_TIMESTAMP:
158 if (len != 4)
159 goto out_invalid_option;
160
161 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
162
163 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
164 dccp_timestamp(sk, &dp->dccps_timestamp_time);
165
166 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
167 debug_prefix, opt_recv->dccpor_timestamp,
168 (unsigned long long)
169 DCCP_SKB_CB(skb)->dccpd_ack_seq);
170 break;
171 case DCCPO_TIMESTAMP_ECHO:
172 if (len != 4 && len != 6 && len != 8)
173 goto out_invalid_option;
174
175 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
176
177 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
178 debug_prefix,
179 opt_recv->dccpor_timestamp_echo,
180 len + 2,
181 (unsigned long long)
182 DCCP_SKB_CB(skb)->dccpd_ack_seq);
183
184
185 if (len == 4)
186 break;
187
188 if (len == 6)
189 elapsed_time = ntohs(*(__be16 *)(value + 4));
190 else
191 elapsed_time = ntohl(*(__be32 *)(value + 4));
192
193 /* Give precedence to the biggest ELAPSED_TIME */
194 if (elapsed_time > opt_recv->dccpor_elapsed_time)
195 opt_recv->dccpor_elapsed_time = elapsed_time;
196 break;
197 case DCCPO_ELAPSED_TIME:
198 if (len != 2 && len != 4)
199 goto out_invalid_option;
200
201 if (pkt_type == DCCP_PKT_DATA)
202 continue;
203
204 if (len == 2)
205 elapsed_time = ntohs(*(__be16 *)value);
206 else
207 elapsed_time = ntohl(*(__be32 *)value);
208
209 if (elapsed_time > opt_recv->dccpor_elapsed_time)
210 opt_recv->dccpor_elapsed_time = elapsed_time;
211
212 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
213 elapsed_time);
214 break;
215 /*
216 * From draft-ietf-dccp-spec-11.txt:
217 *
218 * Option numbers 128 through 191 are for
219 * options sent from the HC-Sender to the
220 * HC-Receiver; option numbers 192 through 255
221 * are for options sent from the HC-Receiver to
222 * the HC-Sender.
223 */
224 case 128 ... 191: {
225 const u16 idx = value - options;
226
227 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
228 opt, len, idx,
229 value) != 0)
230 goto out_invalid_option;
231 }
232 break;
233 case 192 ... 255: {
234 const u16 idx = value - options;
235
236 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
237 opt, len, idx,
238 value) != 0)
239 goto out_invalid_option;
240 }
241 break;
242 default:
243 pr_info("DCCP(%p): option %d(len=%d) not "
244 "implemented, ignoring\n",
245 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 pr_info("DCCP(%p): invalid option %d, len=%d\n", 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 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small"
453 " to insert feature %d option!\n", feat);
454 return -1;
455 }
456
457 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
458
459 to = skb_push(skb, len + 3);
460 *to++ = type;
461 *to++ = len + 3;
462 *to++ = feat;
463
464 if (len)
465 memcpy(to, val, len);
466 dccp_pr_debug("option %d feat %d len %d\n", type, feat, len);
467
468 return 0;
469 }
470
471 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
472 {
473 struct dccp_sock *dp = dccp_sk(sk);
474 struct dccp_opt_pend *opt, *next;
475 int change = 0;
476
477 /* confirm any options [NN opts] */
478 list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_conf,
479 dccpop_node) {
480 dccp_insert_feat_opt(skb, opt->dccpop_type,
481 opt->dccpop_feat, opt->dccpop_val,
482 opt->dccpop_len);
483 /* fear empty confirms */
484 if (opt->dccpop_val)
485 kfree(opt->dccpop_val);
486 kfree(opt);
487 }
488 INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf);
489
490 /* see which features we need to send */
491 list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
492 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
539 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
540
541 if (dp->dccps_options.dccpo_send_ndp_count &&
542 dccp_insert_option_ndp(sk, skb))
543 return -1;
544
545 if (!dccp_packet_without_ack(skb)) {
546 if (dp->dccps_options.dccpo_send_ack_vector &&
547 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
548 dccp_insert_option_ackvec(sk, skb))
549 return -1;
550
551 if (dp->dccps_timestamp_echo != 0 &&
552 dccp_insert_option_timestamp_echo(sk, skb))
553 return -1;
554 }
555
556 if (dp->dccps_hc_rx_insert_options) {
557 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
558 return -1;
559 dp->dccps_hc_rx_insert_options = 0;
560 }
561 if (dp->dccps_hc_tx_insert_options) {
562 if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb))
563 return -1;
564 dp->dccps_hc_tx_insert_options = 0;
565 }
566
567 /* Feature negotiation */
568 /* Data packets can't do feat negotiation */
569 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
570 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
571 dccp_insert_options_feat(sk, skb))
572 return -1;
573
574 /* XXX: insert other options when appropriate */
575
576 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
577 /* The length of all options has to be a multiple of 4 */
578 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
579
580 if (padding != 0) {
581 padding = 4 - padding;
582 memset(skb_push(skb, padding), 0, padding);
583 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
584 }
585 }
586
587 return 0;
588 }
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