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iovec: make sure the caller actually wants anything in memcpy_fromiovecend
[linux/fpc-iii.git] / net / dccp / options.c
blobb4a853ea0ed9fa81e32b41c123a683e9a3afb32b
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 if (len == 0)
135 goto out_invalid_option;
136 rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
137 *value, value + 1, len - 1);
138 if (rc)
139 goto out_featneg_failed;
140 break;
141 case DCCPO_ACK_VECTOR_0:
142 case DCCPO_ACK_VECTOR_1:
143 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
144 break;
145 if (dp->dccps_hc_rx_ackvec != NULL &&
146 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
147 goto out_invalid_option;
148 break;
149 case DCCPO_TIMESTAMP:
150 if (len != 4)
151 goto out_invalid_option;
152 /*
153 * RFC 4340 13.1: "The precise time corresponding to
154 * Timestamp Value zero is not specified". We use
155 * zero to indicate absence of a meaningful timestamp.
156 */
157 opt_val = get_unaligned((__be32 *)value);
158 if (unlikely(opt_val == 0)) {
159 DCCP_WARN("Timestamp with zero value\n");
160 break;
161 }
162
163 if (dreq != NULL) {
164 dreq->dreq_timestamp_echo = ntohl(opt_val);
165 dreq->dreq_timestamp_time = dccp_timestamp();
166 } else {
167 opt_recv->dccpor_timestamp =
168 dp->dccps_timestamp_echo = ntohl(opt_val);
169 dp->dccps_timestamp_time = dccp_timestamp();
170 }
171 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
172 dccp_role(sk), ntohl(opt_val),
173 (unsigned long long)
174 DCCP_SKB_CB(skb)->dccpd_ack_seq);
175 break;
176 case DCCPO_TIMESTAMP_ECHO:
177 if (len != 4 && len != 6 && len != 8)
178 goto out_invalid_option;
179
180 opt_val = get_unaligned((__be32 *)value);
181 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
182
183 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
184 "ackno=%llu", dccp_role(sk),
185 opt_recv->dccpor_timestamp_echo,
186 len + 2,
187 (unsigned long long)
188 DCCP_SKB_CB(skb)->dccpd_ack_seq);
189
190 value += 4;
191
192 if (len == 4) { /* no elapsed time included */
193 dccp_pr_debug_cat("\n");
194 break;
195 }
196
197 if (len == 6) { /* 2-byte elapsed time */
198 __be16 opt_val2 = get_unaligned((__be16 *)value);
199 elapsed_time = ntohs(opt_val2);
200 } else { /* 4-byte elapsed time */
201 opt_val = get_unaligned((__be32 *)value);
202 elapsed_time = ntohl(opt_val);
203 }
204
205 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
206
207 /* Give precedence to the biggest ELAPSED_TIME */
208 if (elapsed_time > opt_recv->dccpor_elapsed_time)
209 opt_recv->dccpor_elapsed_time = elapsed_time;
210 break;
211 case DCCPO_ELAPSED_TIME:
212 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
213 break;
214
215 if (len == 2) {
216 __be16 opt_val2 = get_unaligned((__be16 *)value);
217 elapsed_time = ntohs(opt_val2);
218 } else if (len == 4) {
219 opt_val = get_unaligned((__be32 *)value);
220 elapsed_time = ntohl(opt_val);
221 } else {
222 goto out_invalid_option;
223 }
224
225 if (elapsed_time > opt_recv->dccpor_elapsed_time)
226 opt_recv->dccpor_elapsed_time = elapsed_time;
227
228 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
229 dccp_role(sk), elapsed_time);
230 break;
231 case 128 ... 191: {
232 const u16 idx = value - options;
233
234 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
235 opt, len, idx,
236 value) != 0)
237 goto out_invalid_option;
238 }
239 break;
240 case 192 ... 255: {
241 const u16 idx = value - options;
242
243 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
244 opt, len, idx,
245 value) != 0)
246 goto out_invalid_option;
247 }
248 break;
249 default:
250 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
251 "implemented, ignoring", sk, opt, len);
252 break;
253 }
254 ignore_option:
255 if (opt != DCCPO_MANDATORY)
256 mandatory = 0;
257 }
258
259 /* mandatory was the last byte in option list -> reset connection */
260 if (mandatory)
261 goto out_invalid_option;
262
263 out_nonsensical_length:
264 /* RFC 4340, 5.8: ignore option and all remaining option space */
265 return 0;
266
267 out_invalid_option:
268 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
269 rc = DCCP_RESET_CODE_OPTION_ERROR;
270 out_featneg_failed:
271 DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
272 DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
273 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
274 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
275 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
276 return -1;
277 }
278
279 EXPORT_SYMBOL_GPL(dccp_parse_options);
280
281 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
282 {
283 if (len >= DCCP_OPTVAL_MAXLEN)
284 *to++ = (value & 0xFF0000000000ull) >> 40;
285 if (len > 4)
286 *to++ = (value & 0xFF00000000ull) >> 32;
287 if (len > 3)
288 *to++ = (value & 0xFF000000) >> 24;
289 if (len > 2)
290 *to++ = (value & 0xFF0000) >> 16;
291 if (len > 1)
292 *to++ = (value & 0xFF00) >> 8;
293 if (len > 0)
294 *to++ = (value & 0xFF);
295 }
296
297 static inline u8 dccp_ndp_len(const u64 ndp)
298 {
299 if (likely(ndp <= 0xFF))
300 return 1;
301 return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
302 }
303
304 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
305 const unsigned char option,
306 const void *value, const unsigned char len)
307 {
308 unsigned char *to;
309
310 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
311 return -1;
312
313 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
314
315 to = skb_push(skb, len + 2);
316 *to++ = option;
317 *to++ = len + 2;
318
319 memcpy(to, value, len);
320 return 0;
321 }
322
323 EXPORT_SYMBOL_GPL(dccp_insert_option);
324
325 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
326 {
327 struct dccp_sock *dp = dccp_sk(sk);
328 u64 ndp = dp->dccps_ndp_count;
329
330 if (dccp_non_data_packet(skb))
331 ++dp->dccps_ndp_count;
332 else
333 dp->dccps_ndp_count = 0;
334
335 if (ndp > 0) {
336 unsigned char *ptr;
337 const int ndp_len = dccp_ndp_len(ndp);
338 const int len = ndp_len + 2;
339
340 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
341 return -1;
342
343 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
344
345 ptr = skb_push(skb, len);
346 *ptr++ = DCCPO_NDP_COUNT;
347 *ptr++ = len;
348 dccp_encode_value_var(ndp, ptr, ndp_len);
349 }
350
351 return 0;
352 }
353
354 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
355 {
356 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
357 }
358
359 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
360 u32 elapsed_time)
361 {
362 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
363 const int len = 2 + elapsed_time_len;
364 unsigned char *to;
365
366 if (elapsed_time_len == 0)
367 return 0;
368
369 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
370 return -1;
371
372 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
373
374 to = skb_push(skb, len);
375 *to++ = DCCPO_ELAPSED_TIME;
376 *to++ = len;
377
378 if (elapsed_time_len == 2) {
379 const __be16 var16 = htons((u16)elapsed_time);
380 memcpy(to, &var16, 2);
381 } else {
382 const __be32 var32 = htonl(elapsed_time);
383 memcpy(to, &var32, 4);
384 }
385
386 return 0;
387 }
388
389 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
390
391 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
392 {
393 __be32 now = htonl(dccp_timestamp());
394 /* yes this will overflow but that is the point as we want a
395 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
396
397 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
398 }
399
400 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
401
402 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
403 struct dccp_request_sock *dreq,
404 struct sk_buff *skb)
405 {
406 __be32 tstamp_echo;
407 unsigned char *to;
408 u32 elapsed_time, elapsed_time_len, len;
409
410 if (dreq != NULL) {
411 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
412 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
413 dreq->dreq_timestamp_echo = 0;
414 } else {
415 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
416 tstamp_echo = htonl(dp->dccps_timestamp_echo);
417 dp->dccps_timestamp_echo = 0;
418 }
419
420 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
421 len = 6 + elapsed_time_len;
422
423 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
424 return -1;
425
426 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
427
428 to = skb_push(skb, len);
429 *to++ = DCCPO_TIMESTAMP_ECHO;
430 *to++ = len;
431
432 memcpy(to, &tstamp_echo, 4);
433 to += 4;
434
435 if (elapsed_time_len == 2) {
436 const __be16 var16 = htons((u16)elapsed_time);
437 memcpy(to, &var16, 2);
438 } else if (elapsed_time_len == 4) {
439 const __be32 var32 = htonl(elapsed_time);
440 memcpy(to, &var32, 4);
441 }
442
443 return 0;
444 }
445
446 /**
447 * dccp_insert_option_mandatory - Mandatory option (5.8.2)
448 * Note that since we are using skb_push, this function needs to be called
449 * _after_ inserting the option it is supposed to influence (stack order).
450 */
451 int dccp_insert_option_mandatory(struct sk_buff *skb)
452 {
453 if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
454 return -1;
455
456 DCCP_SKB_CB(skb)->dccpd_opt_len++;
457 *skb_push(skb, 1) = DCCPO_MANDATORY;
458 return 0;
459 }
460
461 /**
462 * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
463 * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
464 * @feat: one out of %dccp_feature_numbers
465 * @val: NN value or SP array (preferred element first) to copy
466 * @len: true length of @val in bytes (excluding first element repetition)
467 * @repeat_first: whether to copy the first element of @val twice
468 * The last argument is used to construct Confirm options, where the preferred
469 * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
470 * lists are kept such that the preferred entry is always first, so we only need
471 * to copy twice, and avoid the overhead of cloning into a bigger array.
472 */
473 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
474 u8 *val, u8 len, bool repeat_first)
475 {
476 u8 tot_len, *to;
477
478 /* take the `Feature' field and possible repetition into account */
479 if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
480 DCCP_WARN("length %u for feature %u too large\n", len, feat);
481 return -1;
482 }
483
484 if (unlikely(val == NULL || len == 0))
485 len = repeat_first = 0;
486 tot_len = 3 + repeat_first + len;
487
488 if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
489 DCCP_WARN("packet too small for feature %d option!\n", feat);
490 return -1;
491 }
492 DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
493
494 to = skb_push(skb, tot_len);
495 *to++ = type;
496 *to++ = tot_len;
497 *to++ = feat;
498
499 if (repeat_first)
500 *to++ = *val;
501 if (len)
502 memcpy(to, val, len);
503 return 0;
504 }
505
506 /* The length of all options needs to be a multiple of 4 (5.8) */
507 static void dccp_insert_option_padding(struct sk_buff *skb)
508 {
509 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
510
511 if (padding != 0) {
512 padding = 4 - padding;
513 memset(skb_push(skb, padding), 0, padding);
514 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
515 }
516 }
517
518 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
519 {
520 struct dccp_sock *dp = dccp_sk(sk);
521
522 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
523
524 if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
525 return -1;
526
527 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
528
529 /* Feature Negotiation */
530 if (dccp_feat_insert_opts(dp, NULL, skb))
531 return -1;
532
533 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
534 /*
535 * Obtain RTT sample from Request/Response exchange.
536 * This is currently used in CCID 3 initialisation.
537 */
538 if (dccp_insert_option_timestamp(sk, skb))
539 return -1;
540
541 } else if (dp->dccps_hc_rx_ackvec != NULL &&
542 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
543 dccp_insert_option_ackvec(sk, skb)) {
544 return -1;
545 }
546 }
547
548 if (dp->dccps_hc_rx_insert_options) {
549 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
550 return -1;
551 dp->dccps_hc_rx_insert_options = 0;
552 }
553
554 if (dp->dccps_timestamp_echo != 0 &&
555 dccp_insert_option_timestamp_echo(dp, NULL, skb))
556 return -1;
557
558 dccp_insert_option_padding(skb);
559 return 0;
560 }
561
562 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
563 {
564 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
565
566 if (dccp_feat_insert_opts(NULL, dreq, 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 }
Linux with added FPC-III support