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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 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); |
58 | unsigned char *opt_ptr = options; |
59 | const unsigned char *opt_end = (unsigned char *)dh + |
60 | (dh->dccph_doff * 4); |
61 | struct dccp_options_received *opt_recv = &dp->dccps_options_received; |
62 | unsigned char opt, len; |
63 | unsigned char *uninitialized_var(value); |
64 | u32 elapsed_time; |
65 | __be32 opt_val; |
66 | int rc; |
67 | int mandatory = 0; |
68 | |
69 | memset(opt_recv, 0, sizeof(*opt_recv)); |
70 | |
71 | opt = len = 0; |
72 | while (opt_ptr != opt_end) { |
73 | opt = *opt_ptr++; |
74 | len = 0; |
75 | value = NULL; |
76 | |
77 | /* Check if this isn't a single byte option */ |
78 | if (opt > DCCPO_MAX_RESERVED) { |
79 | if (opt_ptr == opt_end) |
80 | goto out_nonsensical_length; |
81 | |
82 | len = *opt_ptr++; |
83 | if (len < 2) |
84 | goto out_nonsensical_length; |
85 | /* |
86 | * Remove the type and len fields, leaving |
87 | * just the value size |
88 | */ |
89 | len -= 2; |
90 | value = opt_ptr; |
91 | opt_ptr += len; |
92 | |
93 | if (opt_ptr > opt_end) |
94 | goto out_nonsensical_length; |
95 | } |
96 | |
97 | /* |
98 | * CCID-specific options are ignored during connection setup, as |
99 | * negotiation may still be in progress (see RFC 4340, 10.3). |
100 | * The same applies to Ack Vectors, as these depend on the CCID. |
101 | */ |
102 | if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC || |
103 | opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1)) |
104 | goto ignore_option; |
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 > 6) |
117 | goto out_invalid_option; |
118 | |
119 | opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); |
120 | dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk), |
121 | (unsigned long long)opt_recv->dccpor_ndp); |
122 | break; |
123 | case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R: |
124 | if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */ |
125 | break; |
126 | if (len == 0) |
127 | goto out_invalid_option; |
128 | rc = dccp_feat_parse_options(sk, dreq, mandatory, opt, |
129 | *value, value + 1, len - 1); |
130 | if (rc) |
131 | goto out_featneg_failed; |
132 | break; |
133 | case DCCPO_TIMESTAMP: |
134 | if (len != 4) |
135 | goto out_invalid_option; |
136 | /* |
137 | * RFC 4340 13.1: "The precise time corresponding to |
138 | * Timestamp Value zero is not specified". We use |
139 | * zero to indicate absence of a meaningful timestamp. |
140 | */ |
141 | opt_val = get_unaligned((__be32 *)value); |
142 | if (unlikely(opt_val == 0)) { |
143 | DCCP_WARN("Timestamp with zero value\n"); |
144 | break; |
145 | } |
146 | |
147 | if (dreq != NULL) { |
148 | dreq->dreq_timestamp_echo = ntohl(opt_val); |
149 | dreq->dreq_timestamp_time = dccp_timestamp(); |
150 | } else { |
151 | opt_recv->dccpor_timestamp = |
152 | dp->dccps_timestamp_echo = ntohl(opt_val); |
153 | dp->dccps_timestamp_time = dccp_timestamp(); |
154 | } |
155 | dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n", |
156 | dccp_role(sk), ntohl(opt_val), |
157 | (unsigned long long) |
158 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
159 | /* schedule an Ack in case this sender is quiescent */ |
160 | inet_csk_schedule_ack(sk); |
161 | break; |
162 | case DCCPO_TIMESTAMP_ECHO: |
163 | if (len != 4 && len != 6 && len != 8) |
164 | goto out_invalid_option; |
165 | |
166 | opt_val = get_unaligned((__be32 *)value); |
167 | opt_recv->dccpor_timestamp_echo = ntohl(opt_val); |
168 | |
169 | dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, " |
170 | "ackno=%llu", dccp_role(sk), |
171 | opt_recv->dccpor_timestamp_echo, |
172 | len + 2, |
173 | (unsigned long long) |
174 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
175 | |
176 | value += 4; |
177 | |
178 | if (len == 4) { /* no elapsed time included */ |
179 | dccp_pr_debug_cat("\n"); |
180 | break; |
181 | } |
182 | |
183 | if (len == 6) { /* 2-byte elapsed time */ |
184 | __be16 opt_val2 = get_unaligned((__be16 *)value); |
185 | elapsed_time = ntohs(opt_val2); |
186 | } else { /* 4-byte elapsed time */ |
187 | opt_val = get_unaligned((__be32 *)value); |
188 | elapsed_time = ntohl(opt_val); |
189 | } |
190 | |
191 | dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time); |
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 (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */ |
199 | break; |
200 | |
201 | if (len == 2) { |
202 | __be16 opt_val2 = get_unaligned((__be16 *)value); |
203 | elapsed_time = ntohs(opt_val2); |
204 | } else if (len == 4) { |
205 | opt_val = get_unaligned((__be32 *)value); |
206 | elapsed_time = ntohl(opt_val); |
207 | } else { |
208 | goto out_invalid_option; |
209 | } |
210 | |
211 | if (elapsed_time > opt_recv->dccpor_elapsed_time) |
212 | opt_recv->dccpor_elapsed_time = elapsed_time; |
213 | |
214 | dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", |
215 | dccp_role(sk), elapsed_time); |
216 | break; |
217 | case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC: |
218 | if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, |
219 | pkt_type, opt, value, len)) |
220 | goto out_invalid_option; |
221 | break; |
222 | case DCCPO_ACK_VECTOR_0: |
223 | case DCCPO_ACK_VECTOR_1: |
224 | if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ |
225 | break; |
226 | /* |
227 | * Ack vectors are processed by the TX CCID if it is |
228 | * interested. The RX CCID need not parse Ack Vectors, |
229 | * since it is only interested in clearing old state. |
230 | * Fall through. |
231 | */ |
232 | case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC: |
233 | if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, |
234 | pkt_type, opt, value, len)) |
235 | goto out_invalid_option; |
236 | break; |
237 | default: |
238 | DCCP_CRIT("DCCP(%p): option %d(len=%d) not " |
239 | "implemented, ignoring", sk, opt, len); |
240 | break; |
241 | } |
242 | ignore_option: |
243 | if (opt != DCCPO_MANDATORY) |
244 | mandatory = 0; |
245 | } |
246 | |
247 | /* mandatory was the last byte in option list -> reset connection */ |
248 | if (mandatory) |
249 | goto out_invalid_option; |
250 | |
251 | out_nonsensical_length: |
252 | /* RFC 4340, 5.8: ignore option and all remaining option space */ |
253 | return 0; |
254 | |
255 | out_invalid_option: |
256 | DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); |
257 | rc = DCCP_RESET_CODE_OPTION_ERROR; |
258 | out_featneg_failed: |
259 | DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc); |
260 | DCCP_SKB_CB(skb)->dccpd_reset_code = rc; |
261 | DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt; |
262 | DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0; |
263 | DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0; |
264 | return -1; |
265 | } |
266 | |
267 | EXPORT_SYMBOL_GPL(dccp_parse_options); |
268 | |
269 | void dccp_encode_value_var(const u64 value, u8 *to, const u8 len) |
270 | { |
271 | if (len >= DCCP_OPTVAL_MAXLEN) |
272 | *to++ = (value & 0xFF0000000000ull) >> 40; |
273 | if (len > 4) |
274 | *to++ = (value & 0xFF00000000ull) >> 32; |
275 | if (len > 3) |
276 | *to++ = (value & 0xFF000000) >> 24; |
277 | if (len > 2) |
278 | *to++ = (value & 0xFF0000) >> 16; |
279 | if (len > 1) |
280 | *to++ = (value & 0xFF00) >> 8; |
281 | if (len > 0) |
282 | *to++ = (value & 0xFF); |
283 | } |
284 | |
285 | static inline u8 dccp_ndp_len(const u64 ndp) |
286 | { |
287 | if (likely(ndp <= 0xFF)) |
288 | return 1; |
289 | return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6); |
290 | } |
291 | |
292 | int dccp_insert_option(struct sk_buff *skb, const unsigned char option, |
293 | const void *value, const unsigned char len) |
294 | { |
295 | unsigned char *to; |
296 | |
297 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) |
298 | return -1; |
299 | |
300 | DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; |
301 | |
302 | to = skb_push(skb, len + 2); |
303 | *to++ = option; |
304 | *to++ = len + 2; |
305 | |
306 | memcpy(to, value, len); |
307 | return 0; |
308 | } |
309 | |
310 | EXPORT_SYMBOL_GPL(dccp_insert_option); |
311 | |
312 | static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) |
313 | { |
314 | struct dccp_sock *dp = dccp_sk(sk); |
315 | u64 ndp = dp->dccps_ndp_count; |
316 | |
317 | if (dccp_non_data_packet(skb)) |
318 | ++dp->dccps_ndp_count; |
319 | else |
320 | dp->dccps_ndp_count = 0; |
321 | |
322 | if (ndp > 0) { |
323 | unsigned char *ptr; |
324 | const int ndp_len = dccp_ndp_len(ndp); |
325 | const int len = ndp_len + 2; |
326 | |
327 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
328 | return -1; |
329 | |
330 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
331 | |
332 | ptr = skb_push(skb, len); |
333 | *ptr++ = DCCPO_NDP_COUNT; |
334 | *ptr++ = len; |
335 | dccp_encode_value_var(ndp, ptr, ndp_len); |
336 | } |
337 | |
338 | return 0; |
339 | } |
340 | |
341 | static inline int dccp_elapsed_time_len(const u32 elapsed_time) |
342 | { |
343 | return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; |
344 | } |
345 | |
346 | /* FIXME: This function is currently not used anywhere */ |
347 | int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time) |
348 | { |
349 | const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); |
350 | const int len = 2 + elapsed_time_len; |
351 | unsigned char *to; |
352 | |
353 | if (elapsed_time_len == 0) |
354 | return 0; |
355 | |
356 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
357 | return -1; |
358 | |
359 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
360 | |
361 | to = skb_push(skb, len); |
362 | *to++ = DCCPO_ELAPSED_TIME; |
363 | *to++ = len; |
364 | |
365 | if (elapsed_time_len == 2) { |
366 | const __be16 var16 = htons((u16)elapsed_time); |
367 | memcpy(to, &var16, 2); |
368 | } else { |
369 | const __be32 var32 = htonl(elapsed_time); |
370 | memcpy(to, &var32, 4); |
371 | } |
372 | |
373 | return 0; |
374 | } |
375 | |
376 | EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); |
377 | |
378 | static int dccp_insert_option_timestamp(struct sk_buff *skb) |
379 | { |
380 | __be32 now = htonl(dccp_timestamp()); |
381 | /* yes this will overflow but that is the point as we want a |
382 | * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ |
383 | |
384 | return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now)); |
385 | } |
386 | |
387 | static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, |
388 | struct dccp_request_sock *dreq, |
389 | struct sk_buff *skb) |
390 | { |
391 | __be32 tstamp_echo; |
392 | unsigned char *to; |
393 | u32 elapsed_time, elapsed_time_len, len; |
394 | |
395 | if (dreq != NULL) { |
396 | elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time; |
397 | tstamp_echo = htonl(dreq->dreq_timestamp_echo); |
398 | dreq->dreq_timestamp_echo = 0; |
399 | } else { |
400 | elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time; |
401 | tstamp_echo = htonl(dp->dccps_timestamp_echo); |
402 | dp->dccps_timestamp_echo = 0; |
403 | } |
404 | |
405 | elapsed_time_len = dccp_elapsed_time_len(elapsed_time); |
406 | len = 6 + elapsed_time_len; |
407 | |
408 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
409 | return -1; |
410 | |
411 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
412 | |
413 | to = skb_push(skb, len); |
414 | *to++ = DCCPO_TIMESTAMP_ECHO; |
415 | *to++ = len; |
416 | |
417 | memcpy(to, &tstamp_echo, 4); |
418 | to += 4; |
419 | |
420 | if (elapsed_time_len == 2) { |
421 | const __be16 var16 = htons((u16)elapsed_time); |
422 | memcpy(to, &var16, 2); |
423 | } else if (elapsed_time_len == 4) { |
424 | const __be32 var32 = htonl(elapsed_time); |
425 | memcpy(to, &var32, 4); |
426 | } |
427 | |
428 | return 0; |
429 | } |
430 | |
431 | static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) |
432 | { |
433 | struct dccp_sock *dp = dccp_sk(sk); |
434 | struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; |
435 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
436 | const u16 buflen = dccp_ackvec_buflen(av); |
437 | /* Figure out how many options do we need to represent the ackvec */ |
438 | const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN); |
439 | u16 len = buflen + 2 * nr_opts; |
440 | u8 i, nonce = 0; |
441 | const unsigned char *tail, *from; |
442 | unsigned char *to; |
443 | |
444 | if (dcb->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { |
445 | DCCP_WARN("Lacking space for %u bytes on %s packet\n", len, |
446 | dccp_packet_name(dcb->dccpd_type)); |
447 | return -1; |
448 | } |
449 | /* |
450 | * Since Ack Vectors are variable-length, we can not always predict |
451 | * their size. To catch exception cases where the space is running out |
452 | * on the skb, a separate Sync is scheduled to carry the Ack Vector. |
453 | */ |
454 | if (len > DCCPAV_MIN_OPTLEN && |
455 | len + dcb->dccpd_opt_len + skb->len > dp->dccps_mss_cache) { |
456 | DCCP_WARN("No space left for Ack Vector (%u) on skb (%u+%u), " |
457 | "MPS=%u ==> reduce payload size?\n", len, skb->len, |
458 | dcb->dccpd_opt_len, dp->dccps_mss_cache); |
459 | dp->dccps_sync_scheduled = 1; |
460 | return 0; |
461 | } |
462 | dcb->dccpd_opt_len += len; |
463 | |
464 | to = skb_push(skb, len); |
465 | len = buflen; |
466 | from = av->av_buf + av->av_buf_head; |
467 | tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; |
468 | |
469 | for (i = 0; i < nr_opts; ++i) { |
470 | int copylen = len; |
471 | |
472 | if (len > DCCP_SINGLE_OPT_MAXLEN) |
473 | copylen = DCCP_SINGLE_OPT_MAXLEN; |
474 | |
475 | /* |
476 | * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via |
477 | * its type; ack_nonce is the sum of all individual buf_nonce's. |
478 | */ |
479 | nonce ^= av->av_buf_nonce[i]; |
480 | |
481 | *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i]; |
482 | *to++ = copylen + 2; |
483 | |
484 | /* Check if buf_head wraps */ |
485 | if (from + copylen > tail) { |
486 | const u16 tailsize = tail - from; |
487 | |
488 | memcpy(to, from, tailsize); |
489 | to += tailsize; |
490 | len -= tailsize; |
491 | copylen -= tailsize; |
492 | from = av->av_buf; |
493 | } |
494 | |
495 | memcpy(to, from, copylen); |
496 | from += copylen; |
497 | to += copylen; |
498 | len -= copylen; |
499 | } |
500 | /* |
501 | * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340. |
502 | */ |
503 | if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce)) |
504 | return -ENOBUFS; |
505 | return 0; |
506 | } |
507 | |
508 | /** |
509 | * dccp_insert_option_mandatory - Mandatory option (5.8.2) |
510 | * Note that since we are using skb_push, this function needs to be called |
511 | * _after_ inserting the option it is supposed to influence (stack order). |
512 | */ |
513 | int dccp_insert_option_mandatory(struct sk_buff *skb) |
514 | { |
515 | if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN) |
516 | return -1; |
517 | |
518 | DCCP_SKB_CB(skb)->dccpd_opt_len++; |
519 | *skb_push(skb, 1) = DCCPO_MANDATORY; |
520 | return 0; |
521 | } |
522 | |
523 | /** |
524 | * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb |
525 | * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R |
526 | * @feat: one out of %dccp_feature_numbers |
527 | * @val: NN value or SP array (preferred element first) to copy |
528 | * @len: true length of @val in bytes (excluding first element repetition) |
529 | * @repeat_first: whether to copy the first element of @val twice |
530 | * |
531 | * The last argument is used to construct Confirm options, where the preferred |
532 | * value and the preference list appear separately (RFC 4340, 6.3.1). Preference |
533 | * lists are kept such that the preferred entry is always first, so we only need |
534 | * to copy twice, and avoid the overhead of cloning into a bigger array. |
535 | */ |
536 | int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, |
537 | u8 *val, u8 len, bool repeat_first) |
538 | { |
539 | u8 tot_len, *to; |
540 | |
541 | /* take the `Feature' field and possible repetition into account */ |
542 | if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) { |
543 | DCCP_WARN("length %u for feature %u too large\n", len, feat); |
544 | return -1; |
545 | } |
546 | |
547 | if (unlikely(val == NULL || len == 0)) |
548 | len = repeat_first = false; |
549 | tot_len = 3 + repeat_first + len; |
550 | |
551 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) { |
552 | DCCP_WARN("packet too small for feature %d option!\n", feat); |
553 | return -1; |
554 | } |
555 | DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len; |
556 | |
557 | to = skb_push(skb, tot_len); |
558 | *to++ = type; |
559 | *to++ = tot_len; |
560 | *to++ = feat; |
561 | |
562 | if (repeat_first) |
563 | *to++ = *val; |
564 | if (len) |
565 | memcpy(to, val, len); |
566 | return 0; |
567 | } |
568 | |
569 | /* The length of all options needs to be a multiple of 4 (5.8) */ |
570 | static void dccp_insert_option_padding(struct sk_buff *skb) |
571 | { |
572 | int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; |
573 | |
574 | if (padding != 0) { |
575 | padding = 4 - padding; |
576 | memset(skb_push(skb, padding), 0, padding); |
577 | DCCP_SKB_CB(skb)->dccpd_opt_len += padding; |
578 | } |
579 | } |
580 | |
581 | int dccp_insert_options(struct sock *sk, struct sk_buff *skb) |
582 | { |
583 | struct dccp_sock *dp = dccp_sk(sk); |
584 | |
585 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
586 | |
587 | if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb)) |
588 | return -1; |
589 | |
590 | if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) { |
591 | |
592 | /* Feature Negotiation */ |
593 | if (dccp_feat_insert_opts(dp, NULL, skb)) |
594 | return -1; |
595 | |
596 | if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { |
597 | /* |
598 | * Obtain RTT sample from Request/Response exchange. |
599 | * This is currently used for TFRC initialisation. |
600 | */ |
601 | if (dccp_insert_option_timestamp(skb)) |
602 | return -1; |
603 | |
604 | } else if (dccp_ackvec_pending(sk) && |
605 | dccp_insert_option_ackvec(sk, skb)) { |
606 | return -1; |
607 | } |
608 | } |
609 | |
610 | if (dp->dccps_hc_rx_insert_options) { |
611 | if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) |
612 | return -1; |
613 | dp->dccps_hc_rx_insert_options = 0; |
614 | } |
615 | |
616 | if (dp->dccps_timestamp_echo != 0 && |
617 | dccp_insert_option_timestamp_echo(dp, NULL, skb)) |
618 | return -1; |
619 | |
620 | dccp_insert_option_padding(skb); |
621 | return 0; |
622 | } |
623 | |
624 | int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) |
625 | { |
626 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
627 | |
628 | if (dccp_feat_insert_opts(NULL, dreq, skb)) |
629 | return -1; |
630 | |
631 | /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */ |
632 | if (dccp_insert_option_timestamp(skb)) |
633 | return -1; |
634 | |
635 | if (dreq->dreq_timestamp_echo != 0 && |
636 | dccp_insert_option_timestamp_echo(NULL, dreq, skb)) |
637 | return -1; |
638 | |
639 | dccp_insert_option_padding(skb); |
640 | return 0; |
641 | } |
642 |
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v2.6.34-rc5
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