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RT-AC56 3.0.0.4.374.37 core
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / net / dccp / options.c
blobbfda087bd90dd792f8190840878379d304152c1d
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 <asm/unaligned.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 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
27 {
28 u64 value = 0;
29
30 if (len >= DCCP_OPTVAL_MAXLEN)
31 value += ((u64)*bf++) << 40;
32 if (len > 4)
33 value += ((u64)*bf++) << 32;
34 if (len > 3)
35 value += ((u64)*bf++) << 24;
36 if (len > 2)
37 value += ((u64)*bf++) << 16;
38 if (len > 1)
39 value += ((u64)*bf++) << 8;
40 if (len > 0)
41 value += *bf;
42
43 return value;
44 }
45
46 /**
47 * dccp_parse_options - Parse DCCP options present in @skb
48 * @sk: client|server|listening dccp socket (when @dreq != NULL)
49 * @dreq: request socket to use during connection setup, or NULL
50 */
51 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
52 struct sk_buff *skb)
53 {
54 struct dccp_sock *dp = dccp_sk(sk);
55 const struct dccp_hdr *dh = dccp_hdr(skb);
56 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
57 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
58 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
59 unsigned char *opt_ptr = options;
60 const unsigned char *opt_end = (unsigned char *)dh +
61 (dh->dccph_doff * 4);
62 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
63 unsigned char opt, len;
64 unsigned char *uninitialized_var(value);
65 u32 elapsed_time;
66 __be32 opt_val;
67 int rc;
68 int mandatory = 0;
69
70 memset(opt_recv, 0, sizeof(*opt_recv));
71
72 opt = len = 0;
73 while (opt_ptr != opt_end) {
74 opt = *opt_ptr++;
75 len = 0;
76 value = NULL;
77
78 /* Check if this isn't a single byte option */
79 if (opt > DCCPO_MAX_RESERVED) {
80 if (opt_ptr == opt_end)
81 goto out_nonsensical_length;
82
83 len = *opt_ptr++;
84 if (len < 2)
85 goto out_nonsensical_length;
86 /*
87 * Remove the type and len fields, leaving
88 * just the value size
89 */
90 len -= 2;
91 value = opt_ptr;
92 opt_ptr += len;
93
94 if (opt_ptr > opt_end)
95 goto out_nonsensical_length;
96 }
97
98 /*
99 * CCID-Specific Options (from RFC 4340, sec. 10.3):
100 *
101 * Option numbers 128 through 191 are for options sent from the
102 * HC-Sender to the HC-Receiver; option numbers 192 through 255
103 * are for options sent from the HC-Receiver to the HC-Sender.
104 *
105 * CCID-specific options are ignored during connection setup, as
106 * negotiation may still be in progress (see RFC 4340, 10.3).
107 * The same applies to Ack Vectors, as these depend on the CCID.
108 *
109 */
110 if (dreq != NULL && (opt >= 128 ||
111 opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
112 goto ignore_option;
113
114 switch (opt) {
115 case DCCPO_PADDING:
116 break;
117 case DCCPO_MANDATORY:
118 if (mandatory)
119 goto out_invalid_option;
120 if (pkt_type != DCCP_PKT_DATA)
121 mandatory = 1;
122 break;
123 case DCCPO_NDP_COUNT:
124 if (len > 6)
125 goto out_invalid_option;
126
127 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
128 dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
129 (unsigned long long)opt_recv->dccpor_ndp);
130 break;
131 case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
132 if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
133 break;
134 rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
135 *value, value + 1, len - 1);
136 if (rc)
137 goto out_featneg_failed;
138 break;
139 case DCCPO_ACK_VECTOR_0:
140 case DCCPO_ACK_VECTOR_1:
141 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
142 break;
143 if (dp->dccps_hc_rx_ackvec != NULL &&
144 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
145 goto out_invalid_option;
146 break;
147 case DCCPO_TIMESTAMP:
148 if (len != 4)
149 goto out_invalid_option;
150 /*
151 * RFC 4340 13.1: "The precise time corresponding to
152 * Timestamp Value zero is not specified". We use
153 * zero to indicate absence of a meaningful timestamp.
154 */
155 opt_val = get_unaligned((__be32 *)value);
156 if (unlikely(opt_val == 0)) {
157 DCCP_WARN("Timestamp with zero value\n");
158 break;
159 }
160
161 if (dreq != NULL) {
162 dreq->dreq_timestamp_echo = ntohl(opt_val);
163 dreq->dreq_timestamp_time = dccp_timestamp();
164 } else {
165 opt_recv->dccpor_timestamp =
166 dp->dccps_timestamp_echo = ntohl(opt_val);
167 dp->dccps_timestamp_time = dccp_timestamp();
168 }
169 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
170 dccp_role(sk), ntohl(opt_val),
171 (unsigned long long)
172 DCCP_SKB_CB(skb)->dccpd_ack_seq);
173 break;
174 case DCCPO_TIMESTAMP_ECHO:
175 if (len != 4 && len != 6 && len != 8)
176 goto out_invalid_option;
177
178 opt_val = get_unaligned((__be32 *)value);
179 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
180
181 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
182 "ackno=%llu", dccp_role(sk),
183 opt_recv->dccpor_timestamp_echo,
184 len + 2,
185 (unsigned long long)
186 DCCP_SKB_CB(skb)->dccpd_ack_seq);
187
188 value += 4;
189
190 if (len == 4) { /* no elapsed time included */
191 dccp_pr_debug_cat("\n");
192 break;
193 }
194
195 if (len == 6) { /* 2-byte elapsed time */
196 __be16 opt_val2 = get_unaligned((__be16 *)value);
197 elapsed_time = ntohs(opt_val2);
198 } else { /* 4-byte elapsed time */
199 opt_val = get_unaligned((__be32 *)value);
200 elapsed_time = ntohl(opt_val);
201 }
202
203 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
204
205 /* Give precedence to the biggest ELAPSED_TIME */
206 if (elapsed_time > opt_recv->dccpor_elapsed_time)
207 opt_recv->dccpor_elapsed_time = elapsed_time;
208 break;
209 case DCCPO_ELAPSED_TIME:
210 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
211 break;
212
213 if (len == 2) {
214 __be16 opt_val2 = get_unaligned((__be16 *)value);
215 elapsed_time = ntohs(opt_val2);
216 } else if (len == 4) {
217 opt_val = get_unaligned((__be32 *)value);
218 elapsed_time = ntohl(opt_val);
219 } else {
220 goto out_invalid_option;
221 }
222
223 if (elapsed_time > opt_recv->dccpor_elapsed_time)
224 opt_recv->dccpor_elapsed_time = elapsed_time;
225
226 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
227 dccp_role(sk), elapsed_time);
228 break;
229 case 128 ... 191: {
230 const u16 idx = value - options;
231
232 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
233 opt, len, idx,
234 value) != 0)
235 goto out_invalid_option;
236 }
237 break;
238 case 192 ... 255: {
239 const u16 idx = value - options;
240
241 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
242 opt, len, idx,
243 value) != 0)
244 goto out_invalid_option;
245 }
246 break;
247 default:
248 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
249 "implemented, ignoring", sk, opt, len);
250 break;
251 }
252 ignore_option:
253 if (opt != DCCPO_MANDATORY)
254 mandatory = 0;
255 }
256
257 /* mandatory was the last byte in option list -> reset connection */
258 if (mandatory)
259 goto out_invalid_option;
260
261 out_nonsensical_length:
262 /* RFC 4340, 5.8: ignore option and all remaining option space */
263 return 0;
264
265 out_invalid_option:
266 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
267 rc = DCCP_RESET_CODE_OPTION_ERROR;
268 out_featneg_failed:
269 DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
270 DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
271 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
272 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
273 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
274 return -1;
275 }
276
277 EXPORT_SYMBOL_GPL(dccp_parse_options);
278
279 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
280 {
281 if (len >= DCCP_OPTVAL_MAXLEN)
282 *to++ = (value & 0xFF0000000000ull) >> 40;
283 if (len > 4)
284 *to++ = (value & 0xFF00000000ull) >> 32;
285 if (len > 3)
286 *to++ = (value & 0xFF000000) >> 24;
287 if (len > 2)
288 *to++ = (value & 0xFF0000) >> 16;
289 if (len > 1)
290 *to++ = (value & 0xFF00) >> 8;
291 if (len > 0)
292 *to++ = (value & 0xFF);
293 }
294
295 static inline u8 dccp_ndp_len(const u64 ndp)
296 {
297 if (likely(ndp <= 0xFF))
298 return 1;
299 return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
300 }
301
302 int dccp_insert_option(struct sk_buff *skb, const unsigned char option,
303 const void *value, const unsigned char len)
304 {
305 unsigned char *to;
306
307 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
308 return -1;
309
310 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
311
312 to = skb_push(skb, len + 2);
313 *to++ = option;
314 *to++ = len + 2;
315
316 memcpy(to, value, len);
317 return 0;
318 }
319
320 EXPORT_SYMBOL_GPL(dccp_insert_option);
321
322 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
323 {
324 struct dccp_sock *dp = dccp_sk(sk);
325 u64 ndp = dp->dccps_ndp_count;
326
327 if (dccp_non_data_packet(skb))
328 ++dp->dccps_ndp_count;
329 else
330 dp->dccps_ndp_count = 0;
331
332 if (ndp > 0) {
333 unsigned char *ptr;
334 const int ndp_len = dccp_ndp_len(ndp);
335 const int len = ndp_len + 2;
336
337 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
338 return -1;
339
340 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
341
342 ptr = skb_push(skb, len);
343 *ptr++ = DCCPO_NDP_COUNT;
344 *ptr++ = len;
345 dccp_encode_value_var(ndp, ptr, ndp_len);
346 }
347
348 return 0;
349 }
350
351 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
352 {
353 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
354 }
355
356 int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
357 {
358 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
359 const int len = 2 + elapsed_time_len;
360 unsigned char *to;
361
362 if (elapsed_time_len == 0)
363 return 0;
364
365 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
366 return -1;
367
368 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
369
370 to = skb_push(skb, len);
371 *to++ = DCCPO_ELAPSED_TIME;
372 *to++ = len;
373
374 if (elapsed_time_len == 2) {
375 const __be16 var16 = htons((u16)elapsed_time);
376 memcpy(to, &var16, 2);
377 } else {
378 const __be32 var32 = htonl(elapsed_time);
379 memcpy(to, &var32, 4);
380 }
381
382 return 0;
383 }
384
385 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
386
387 int dccp_insert_option_timestamp(struct sk_buff *skb)
388 {
389 __be32 now = htonl(dccp_timestamp());
390 /* yes this will overflow but that is the point as we want a
391 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
392
393 return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
394 }
395
396 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
397
398 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
399 struct dccp_request_sock *dreq,
400 struct sk_buff *skb)
401 {
402 __be32 tstamp_echo;
403 unsigned char *to;
404 u32 elapsed_time, elapsed_time_len, len;
405
406 if (dreq != NULL) {
407 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
408 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
409 dreq->dreq_timestamp_echo = 0;
410 } else {
411 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
412 tstamp_echo = htonl(dp->dccps_timestamp_echo);
413 dp->dccps_timestamp_echo = 0;
414 }
415
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 memcpy(to, &tstamp_echo, 4);
429 to += 4;
430
431 if (elapsed_time_len == 2) {
432 const __be16 var16 = htons((u16)elapsed_time);
433 memcpy(to, &var16, 2);
434 } else if (elapsed_time_len == 4) {
435 const __be32 var32 = htonl(elapsed_time);
436 memcpy(to, &var32, 4);
437 }
438
439 return 0;
440 }
441
442 /**
443 * dccp_insert_option_mandatory - Mandatory option (5.8.2)
444 * Note that since we are using skb_push, this function needs to be called
445 * _after_ inserting the option it is supposed to influence (stack order).
446 */
447 int dccp_insert_option_mandatory(struct sk_buff *skb)
448 {
449 if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
450 return -1;
451
452 DCCP_SKB_CB(skb)->dccpd_opt_len++;
453 *skb_push(skb, 1) = DCCPO_MANDATORY;
454 return 0;
455 }
456
457 /**
458 * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
459 * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
460 * @feat: one out of %dccp_feature_numbers
461 * @val: NN value or SP array (preferred element first) to copy
462 * @len: true length of @val in bytes (excluding first element repetition)
463 * @repeat_first: whether to copy the first element of @val twice
464 * The last argument is used to construct Confirm options, where the preferred
465 * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
466 * lists are kept such that the preferred entry is always first, so we only need
467 * to copy twice, and avoid the overhead of cloning into a bigger array.
468 */
469 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
470 u8 *val, u8 len, bool repeat_first)
471 {
472 u8 tot_len, *to;
473
474 /* take the `Feature' field and possible repetition into account */
475 if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
476 DCCP_WARN("length %u for feature %u too large\n", len, feat);
477 return -1;
478 }
479
480 if (unlikely(val == NULL || len == 0))
481 len = repeat_first = 0;
482 tot_len = 3 + repeat_first + len;
483
484 if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
485 DCCP_WARN("packet too small for feature %d option!\n", feat);
486 return -1;
487 }
488 DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
489
490 to = skb_push(skb, tot_len);
491 *to++ = type;
492 *to++ = tot_len;
493 *to++ = feat;
494
495 if (repeat_first)
496 *to++ = *val;
497 if (len)
498 memcpy(to, val, len);
499 return 0;
500 }
501
502 /* The length of all options needs to be a multiple of 4 (5.8) */
503 static void dccp_insert_option_padding(struct sk_buff *skb)
504 {
505 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
506
507 if (padding != 0) {
508 padding = 4 - padding;
509 memset(skb_push(skb, padding), 0, padding);
510 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
511 }
512 }
513
514 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
515 {
516 struct dccp_sock *dp = dccp_sk(sk);
517
518 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
519
520 if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
521 return -1;
522
523 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
524
525 /* Feature Negotiation */
526 if (dccp_feat_insert_opts(dp, NULL, skb))
527 return -1;
528
529 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
530 /*
531 * Obtain RTT sample from Request/Response exchange.
532 * This is currently used for TFRC initialisation.
533 */
534 if (dccp_insert_option_timestamp(skb))
535 return -1;
536
537 } else if (dp->dccps_hc_rx_ackvec != NULL &&
538 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
539 dccp_insert_option_ackvec(sk, skb)) {
540 return -1;
541 }
542 }
543
544 if (dp->dccps_hc_rx_insert_options) {
545 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
546 return -1;
547 dp->dccps_hc_rx_insert_options = 0;
548 }
549
550 if (dp->dccps_timestamp_echo != 0 &&
551 dccp_insert_option_timestamp_echo(dp, NULL, skb))
552 return -1;
553
554 dccp_insert_option_padding(skb);
555 return 0;
556 }
557
558 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
559 {
560 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
561
562 if (dccp_feat_insert_opts(NULL, dreq, skb))
563 return -1;
564
565 /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */
566 if (dccp_insert_option_timestamp(skb))
567 return -1;
568
569 if (dreq->dreq_timestamp_echo != 0 &&
570 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
571 return -1;
572
573 dccp_insert_option_padding(skb);
574 return 0;
575 }
Tomato firmware and modifications.