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[CREDITS]: Update Arnaldo entry
[linux-2.6/libata-dev.git] / net / dccp / options.c
blob14b6212273239439437cb399f4666480ecfe4473
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 break;
184
185 if (len == 6)
186 elapsed_time = ntohs(*(__be16 *)(value + 4));
187 else
188 elapsed_time = ntohl(*(__be32 *)(value + 4));
189
190 /* Give precedence to the biggest ELAPSED_TIME */
191 if (elapsed_time > opt_recv->dccpor_elapsed_time)
192 opt_recv->dccpor_elapsed_time = elapsed_time;
193 break;
194 case DCCPO_ELAPSED_TIME:
195 if (len != 2 && len != 4)
196 goto out_invalid_option;
197
198 if (pkt_type == DCCP_PKT_DATA)
199 continue;
200
201 if (len == 2)
202 elapsed_time = ntohs(*(__be16 *)value);
203 else
204 elapsed_time = ntohl(*(__be32 *)value);
205
206 if (elapsed_time > opt_recv->dccpor_elapsed_time)
207 opt_recv->dccpor_elapsed_time = elapsed_time;
208
209 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
210 dccp_role(sk), elapsed_time);
211 break;
212 /*
213 * From RFC 4340, sec. 10.3:
214 *
215 * Option numbers 128 through 191 are for
216 * options sent from the HC-Sender to the
217 * HC-Receiver; option numbers 192 through 255
218 * are for options sent from the HC-Receiver to
219 * the HC-Sender.
220 */
221 case 128 ... 191: {
222 const u16 idx = value - options;
223
224 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
225 opt, len, idx,
226 value) != 0)
227 goto out_invalid_option;
228 }
229 break;
230 case 192 ... 255: {
231 const u16 idx = value - options;
232
233 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
234 opt, len, idx,
235 value) != 0)
236 goto out_invalid_option;
237 }
238 break;
239 default:
240 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
241 "implemented, ignoring", sk, opt, len);
242 break;
243 }
244
245 if (opt != DCCPO_MANDATORY)
246 mandatory = 0;
247 }
248
249 /* mandatory was the last byte in option list -> reset connection */
250 if (mandatory)
251 goto out_invalid_option;
252
253 return 0;
254
255 out_invalid_option:
256 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
257 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
258 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
259 return -1;
260 }
261
262 EXPORT_SYMBOL_GPL(dccp_parse_options);
263
264 static void dccp_encode_value_var(const u32 value, unsigned char *to,
265 const unsigned int len)
266 {
267 if (len > 3)
268 *to++ = (value & 0xFF000000) >> 24;
269 if (len > 2)
270 *to++ = (value & 0xFF0000) >> 16;
271 if (len > 1)
272 *to++ = (value & 0xFF00) >> 8;
273 if (len > 0)
274 *to++ = (value & 0xFF);
275 }
276
277 static inline int dccp_ndp_len(const int ndp)
278 {
279 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
280 }
281
282 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
283 const unsigned char option,
284 const void *value, const unsigned char len)
285 {
286 unsigned char *to;
287
288 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
289 return -1;
290
291 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
292
293 to = skb_push(skb, len + 2);
294 *to++ = option;
295 *to++ = len + 2;
296
297 memcpy(to, value, len);
298 return 0;
299 }
300
301 EXPORT_SYMBOL_GPL(dccp_insert_option);
302
303 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
304 {
305 struct dccp_sock *dp = dccp_sk(sk);
306 int ndp = dp->dccps_ndp_count;
307
308 if (dccp_non_data_packet(skb))
309 ++dp->dccps_ndp_count;
310 else
311 dp->dccps_ndp_count = 0;
312
313 if (ndp > 0) {
314 unsigned char *ptr;
315 const int ndp_len = dccp_ndp_len(ndp);
316 const int len = ndp_len + 2;
317
318 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
319 return -1;
320
321 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
322
323 ptr = skb_push(skb, len);
324 *ptr++ = DCCPO_NDP_COUNT;
325 *ptr++ = len;
326 dccp_encode_value_var(ndp, ptr, ndp_len);
327 }
328
329 return 0;
330 }
331
332 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
333 {
334 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
335 }
336
337 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
338 u32 elapsed_time)
339 {
340 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
341 const int len = 2 + elapsed_time_len;
342 unsigned char *to;
343
344 if (elapsed_time_len == 0)
345 return 0;
346
347 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
348 return -1;
349
350 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
351
352 to = skb_push(skb, len);
353 *to++ = DCCPO_ELAPSED_TIME;
354 *to++ = len;
355
356 if (elapsed_time_len == 2) {
357 const __be16 var16 = htons((u16)elapsed_time);
358 memcpy(to, &var16, 2);
359 } else {
360 const __be32 var32 = htonl(elapsed_time);
361 memcpy(to, &var32, 4);
362 }
363
364 return 0;
365 }
366
367 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
368
369 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
370 {
371 const struct dccp_sock *dp = dccp_sk(sk);
372
373 do_gettimeofday(tv);
374 tv->tv_sec -= dp->dccps_epoch.tv_sec;
375 tv->tv_usec -= dp->dccps_epoch.tv_usec;
376
377 while (tv->tv_usec < 0) {
378 tv->tv_sec--;
379 tv->tv_usec += USEC_PER_SEC;
380 }
381 }
382
383 EXPORT_SYMBOL_GPL(dccp_timestamp);
384
385 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
386 {
387 struct timeval tv;
388 __be32 now;
389
390 dccp_timestamp(sk, &tv);
391 now = htonl(timeval_usecs(&tv) / 10);
392 /* yes this will overflow but that is the point as we want a
393 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
394
395 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
396 }
397
398 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
399
400 static int dccp_insert_option_timestamp_echo(struct sock *sk,
401 struct sk_buff *skb)
402 {
403 struct dccp_sock *dp = dccp_sk(sk);
404 struct timeval now;
405 __be32 tstamp_echo;
406 u32 elapsed_time;
407 int len, elapsed_time_len;
408 unsigned char *to;
409
410 dccp_timestamp(sk, &now);
411 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
412 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
413 len = 6 + elapsed_time_len;
414
415 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
416 return -1;
417
418 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
419
420 to = skb_push(skb, len);
421 *to++ = DCCPO_TIMESTAMP_ECHO;
422 *to++ = len;
423
424 tstamp_echo = htonl(dp->dccps_timestamp_echo);
425 memcpy(to, &tstamp_echo, 4);
426 to += 4;
427
428 if (elapsed_time_len == 2) {
429 const __be16 var16 = htons((u16)elapsed_time);
430 memcpy(to, &var16, 2);
431 } else if (elapsed_time_len == 4) {
432 const __be32 var32 = htonl(elapsed_time);
433 memcpy(to, &var32, 4);
434 }
435
436 dp->dccps_timestamp_echo = 0;
437 dp->dccps_timestamp_time.tv_sec = 0;
438 dp->dccps_timestamp_time.tv_usec = 0;
439 return 0;
440 }
441
442 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
443 u8 *val, u8 len)
444 {
445 u8 *to;
446
447 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
448 DCCP_WARN("packet too small for feature %d option!\n", feat);
449 return -1;
450 }
451
452 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
453
454 to = skb_push(skb, len + 3);
455 *to++ = type;
456 *to++ = len + 3;
457 *to++ = feat;
458
459 if (len)
460 memcpy(to, val, len);
461
462 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
463 dccp_feat_typename(type),
464 dccp_feat_name(feat), feat, len);
465 return 0;
466 }
467
468 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
469 {
470 struct dccp_sock *dp = dccp_sk(sk);
471 struct dccp_minisock *dmsk = dccp_msk(sk);
472 struct dccp_opt_pend *opt, *next;
473 int change = 0;
474
475 /* confirm any options [NN opts] */
476 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
477 dccp_insert_feat_opt(skb, opt->dccpop_type,
478 opt->dccpop_feat, opt->dccpop_val,
479 opt->dccpop_len);
480 /* fear empty confirms */
481 if (opt->dccpop_val)
482 kfree(opt->dccpop_val);
483 kfree(opt);
484 }
485 INIT_LIST_HEAD(&dmsk->dccpms_conf);
486
487 /* see which features we need to send */
488 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
489 /* see if we need to send any confirm */
490 if (opt->dccpop_sc) {
491 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
492 opt->dccpop_feat,
493 opt->dccpop_sc->dccpoc_val,
494 opt->dccpop_sc->dccpoc_len);
495
496 BUG_ON(!opt->dccpop_sc->dccpoc_val);
497 kfree(opt->dccpop_sc->dccpoc_val);
498 kfree(opt->dccpop_sc);
499 opt->dccpop_sc = NULL;
500 }
501
502 /* any option not confirmed, re-send it */
503 if (!opt->dccpop_conf) {
504 dccp_insert_feat_opt(skb, opt->dccpop_type,
505 opt->dccpop_feat, opt->dccpop_val,
506 opt->dccpop_len);
507 change++;
508 }
509 }
510
511 /* Retransmit timer.
512 * If this is the master listening sock, we don't set a timer on it. It
513 * should be fine because if the dude doesn't receive our RESPONSE
514 * [which will contain the CHANGE] he will send another REQUEST which
515 * will "retrnasmit" the change.
516 */
517 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
518 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
519
520 /* XXX don't reset the timer on re-transmissions. I.e. reset it
521 * only when sending new stuff i guess. Currently the timer
522 * never backs off because on re-transmission it just resets it!
523 */
524 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
525 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
526 }
527
528 return 0;
529 }
530
531 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
532 {
533 struct dccp_sock *dp = dccp_sk(sk);
534 struct dccp_minisock *dmsk = dccp_msk(sk);
535
536 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
537
538 if (dmsk->dccpms_send_ndp_count &&
539 dccp_insert_option_ndp(sk, skb))
540 return -1;
541
542 if (!dccp_packet_without_ack(skb)) {
543 if (dmsk->dccpms_send_ack_vector &&
544 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
545 dccp_insert_option_ackvec(sk, skb))
546 return -1;
547
548 if (dp->dccps_timestamp_echo != 0 &&
549 dccp_insert_option_timestamp_echo(sk, skb))
550 return -1;
551 }
552
553 if (dp->dccps_hc_rx_insert_options) {
554 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
555 return -1;
556 dp->dccps_hc_rx_insert_options = 0;
557 }
558
559 /* Feature negotiation */
560 /* Data packets can't do feat negotiation */
561 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
562 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
563 dccp_insert_options_feat(sk, skb))
564 return -1;
565
566 /*
567 * Obtain RTT sample from Request/Response exchange.
568 * This is currently used in CCID 3 initialisation.
569 */
570 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
571 dccp_insert_option_timestamp(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 }
Linux 2.6 libata-dev (mirror)