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Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/options.c | |
3 | * | |
4 | * An implementation of the DCCP protocol | |
1bc09869 IM |
5 | * Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org> |
6 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> | |
e6bccd35 | 7 | * Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz> |
7c657876 ACM |
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 | */ | |
7c657876 ACM |
14 | #include <linux/dccp.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/types.h> | |
76fd1e87 | 17 | #include <asm/unaligned.h> |
7c657876 ACM |
18 | #include <linux/kernel.h> |
19 | #include <linux/skbuff.h> | |
20 | ||
ae31c339 | 21 | #include "ackvec.h" |
7c657876 ACM |
22 | #include "ccid.h" |
23 | #include "dccp.h" | |
afe00251 | 24 | #include "feat.h" |
7c657876 | 25 | |
02fa460e | 26 | u64 dccp_decode_value_var(const u8 *bf, const u8 len) |
7c657876 | 27 | { |
02fa460e | 28 | u64 value = 0; |
7c657876 | 29 | |
02fa460e GR |
30 | if (len >= DCCP_OPTVAL_MAXLEN) |
31 | value += ((u64)*bf++) << 40; | |
32 | if (len > 4) | |
33 | value += ((u64)*bf++) << 32; | |
7c657876 | 34 | if (len > 3) |
02fa460e | 35 | value += ((u64)*bf++) << 24; |
7c657876 | 36 | if (len > 2) |
02fa460e | 37 | value += ((u64)*bf++) << 16; |
7c657876 | 38 | if (len > 1) |
02fa460e | 39 | value += ((u64)*bf++) << 8; |
7c657876 ACM |
40 | if (len > 0) |
41 | value += *bf; | |
42 | ||
43 | return value; | |
44 | } | |
45 | ||
8b819412 GR |
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) | |
7c657876 ACM |
53 | { |
54 | struct dccp_sock *dp = dccp_sk(sk); | |
7c657876 ACM |
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; | |
7690af3f ACM |
59 | const unsigned char *opt_end = (unsigned char *)dh + |
60 | (dh->dccph_doff * 4); | |
7c657876 ACM |
61 | struct dccp_options_received *opt_recv = &dp->dccps_options_received; |
62 | unsigned char opt, len; | |
3ed7cc0f | 63 | unsigned char *uninitialized_var(value); |
1c14ac0a | 64 | u32 elapsed_time; |
76fd1e87 | 65 | __be32 opt_val; |
afe00251 AB |
66 | int rc; |
67 | int mandatory = 0; | |
7c657876 ACM |
68 | |
69 | memset(opt_recv, 0, sizeof(*opt_recv)); | |
70 | ||
fb950496 | 71 | opt = len = 0; |
7c657876 ACM |
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) | |
faf61c33 | 80 | goto out_nonsensical_length; |
7c657876 ACM |
81 | |
82 | len = *opt_ptr++; | |
faf61c33 GR |
83 | if (len < 2) |
84 | goto out_nonsensical_length; | |
7c657876 ACM |
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) | |
faf61c33 | 94 | goto out_nonsensical_length; |
7c657876 ACM |
95 | } |
96 | ||
8b819412 | 97 | /* |
8b819412 GR |
98 | * CCID-specific options are ignored during connection setup, as |
99 | * negotiation may still be in progress (see RFC 4340, 10.3). | |
65907a43 | 100 | * The same applies to Ack Vectors, as these depend on the CCID. |
8b819412 | 101 | */ |
a18213d1 | 102 | if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC || |
65907a43 | 103 | opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1)) |
8b819412 GR |
104 | goto ignore_option; |
105 | ||
7c657876 ACM |
106 | switch (opt) { |
107 | case DCCPO_PADDING: | |
108 | break; | |
afe00251 AB |
109 | case DCCPO_MANDATORY: |
110 | if (mandatory) | |
111 | goto out_invalid_option; | |
6df9424a ACM |
112 | if (pkt_type != DCCP_PKT_DATA) |
113 | mandatory = 1; | |
afe00251 | 114 | break; |
7c657876 | 115 | case DCCPO_NDP_COUNT: |
5b5d0e70 | 116 | if (len > 6) |
7c657876 ACM |
117 | goto out_invalid_option; |
118 | ||
119 | opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); | |
5b5d0e70 GR |
120 | dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk), |
121 | (unsigned long long)opt_recv->dccpor_ndp); | |
7c657876 | 122 | break; |
b1ad0042 GR |
123 | case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R: |
124 | if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */ | |
cf86314c | 125 | break; |
a2948659 DR |
126 | if (len == 0) |
127 | goto out_invalid_option; | |
e77b8363 GR |
128 | rc = dccp_feat_parse_options(sk, dreq, mandatory, opt, |
129 | *value, value + 1, len - 1); | |
130 | if (rc) | |
131 | goto out_featneg_failed; | |
410e27a4 | 132 | break; |
7c657876 ACM |
133 | case DCCPO_TIMESTAMP: |
134 | if (len != 4) | |
135 | goto out_invalid_option; | |
b4d4f7c7 GR |
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 | */ | |
76fd1e87 | 141 | opt_val = get_unaligned((__be32 *)value); |
b4d4f7c7 GR |
142 | if (unlikely(opt_val == 0)) { |
143 | DCCP_WARN("Timestamp with zero value\n"); | |
144 | break; | |
145 | } | |
7c657876 | 146 | |
b4d4f7c7 GR |
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 | } | |
09dbc389 | 155 | dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n", |
b4d4f7c7 | 156 | dccp_role(sk), ntohl(opt_val), |
f6ccf554 | 157 | (unsigned long long) |
7c657876 | 158 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
ecdfbdab GR |
159 | /* schedule an Ack in case this sender is quiescent */ |
160 | inet_csk_schedule_ack(sk); | |
7c657876 ACM |
161 | break; |
162 | case DCCPO_TIMESTAMP_ECHO: | |
1bc09869 | 163 | if (len != 4 && len != 6 && len != 8) |
7c657876 ACM |
164 | goto out_invalid_option; |
165 | ||
76fd1e87 GR |
166 | opt_val = get_unaligned((__be32 *)value); |
167 | opt_recv->dccpor_timestamp_echo = ntohl(opt_val); | |
7c657876 | 168 | |
09dbc389 | 169 | dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, " |
f73f7097 | 170 | "ackno=%llu", dccp_role(sk), |
7690af3f | 171 | opt_recv->dccpor_timestamp_echo, |
f6ccf554 DM |
172 | len + 2, |
173 | (unsigned long long) | |
1bc09869 IM |
174 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
175 | ||
76fd1e87 | 176 | value += 4; |
1bc09869 | 177 | |
76fd1e87 | 178 | if (len == 4) { /* no elapsed time included */ |
f73f7097 | 179 | dccp_pr_debug_cat("\n"); |
1c14ac0a | 180 | break; |
f73f7097 | 181 | } |
1c14ac0a | 182 | |
76fd1e87 GR |
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 | } | |
1c14ac0a | 190 | |
dcad856f | 191 | dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time); |
f73f7097 | 192 | |
1c14ac0a ACM |
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; | |
7c657876 ACM |
196 | break; |
197 | case DCCPO_ELAPSED_TIME: | |
c86ab2b6 GR |
198 | if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */ |
199 | break; | |
1bc09869 | 200 | |
76fd1e87 GR |
201 | if (len == 2) { |
202 | __be16 opt_val2 = get_unaligned((__be16 *)value); | |
203 | elapsed_time = ntohs(opt_val2); | |
c86ab2b6 | 204 | } else if (len == 4) { |
76fd1e87 GR |
205 | opt_val = get_unaligned((__be32 *)value); |
206 | elapsed_time = ntohl(opt_val); | |
c86ab2b6 GR |
207 | } else { |
208 | goto out_invalid_option; | |
76fd1e87 | 209 | } |
1c14ac0a ACM |
210 | |
211 | if (elapsed_time > opt_recv->dccpor_elapsed_time) | |
212 | opt_recv->dccpor_elapsed_time = elapsed_time; | |
1bc09869 | 213 | |
09dbc389 GR |
214 | dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", |
215 | dccp_role(sk), elapsed_time); | |
7c657876 | 216 | break; |
a18213d1 | 217 | case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC: |
7690af3f | 218 | if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, |
4874c131 | 219 | pkt_type, opt, value, len)) |
7c657876 | 220 | goto out_invalid_option; |
7c657876 | 221 | break; |
7e87fe84 GR |
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 | */ | |
a18213d1 | 232 | case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC: |
7690af3f | 233 | if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, |
4874c131 | 234 | pkt_type, opt, value, len)) |
7c657876 | 235 | goto out_invalid_option; |
7c657876 ACM |
236 | break; |
237 | default: | |
59348b19 GR |
238 | DCCP_CRIT("DCCP(%p): option %d(len=%d) not " |
239 | "implemented, ignoring", sk, opt, len); | |
7c657876 | 240 | break; |
c9eaf173 | 241 | } |
8b819412 | 242 | ignore_option: |
afe00251 AB |
243 | if (opt != DCCPO_MANDATORY) |
244 | mandatory = 0; | |
7c657876 ACM |
245 | } |
246 | ||
6df9424a ACM |
247 | /* mandatory was the last byte in option list -> reset connection */ |
248 | if (mandatory) | |
249 | goto out_invalid_option; | |
250 | ||
faf61c33 GR |
251 | out_nonsensical_length: |
252 | /* RFC 4340, 5.8: ignore option and all remaining option space */ | |
7c657876 ACM |
253 | return 0; |
254 | ||
255 | out_invalid_option: | |
256 | DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); | |
e77b8363 GR |
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; | |
eac7726b GR |
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; | |
7c657876 ACM |
264 | return -1; |
265 | } | |
266 | ||
b61fafc4 ACM |
267 | EXPORT_SYMBOL_GPL(dccp_parse_options); |
268 | ||
02fa460e | 269 | void dccp_encode_value_var(const u64 value, u8 *to, const u8 len) |
7c657876 | 270 | { |
02fa460e GR |
271 | if (len >= DCCP_OPTVAL_MAXLEN) |
272 | *to++ = (value & 0xFF0000000000ull) >> 40; | |
273 | if (len > 4) | |
274 | *to++ = (value & 0xFF00000000ull) >> 32; | |
7c657876 ACM |
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 | ||
5b5d0e70 | 285 | static inline u8 dccp_ndp_len(const u64 ndp) |
7c657876 | 286 | { |
5b5d0e70 GR |
287 | if (likely(ndp <= 0xFF)) |
288 | return 1; | |
4be929be | 289 | return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6); |
7c657876 ACM |
290 | } |
291 | ||
a7d13fbf GR |
292 | int dccp_insert_option(struct sk_buff *skb, const unsigned char option, |
293 | const void *value, const unsigned char len) | |
7c657876 ACM |
294 | { |
295 | unsigned char *to; | |
296 | ||
2d0817d1 ACM |
297 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) |
298 | return -1; | |
7c657876 ACM |
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); | |
2d0817d1 | 307 | return 0; |
7c657876 ACM |
308 | } |
309 | ||
310 | EXPORT_SYMBOL_GPL(dccp_insert_option); | |
311 | ||
2d0817d1 | 312 | static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
313 | { |
314 | struct dccp_sock *dp = dccp_sk(sk); | |
5b5d0e70 | 315 | u64 ndp = dp->dccps_ndp_count; |
7c657876 ACM |
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) | |
2d0817d1 | 328 | return -1; |
7c657876 ACM |
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 | } | |
2d0817d1 ACM |
337 | |
338 | return 0; | |
7c657876 ACM |
339 | } |
340 | ||
341 | static inline int dccp_elapsed_time_len(const u32 elapsed_time) | |
342 | { | |
b1c9fe7b | 343 | return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; |
7c657876 ACM |
344 | } |
345 | ||
f17a37c9 | 346 | /* FIXME: This function is currently not used anywhere */ |
a7d13fbf | 347 | int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time) |
7c657876 | 348 | { |
7c657876 ACM |
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 | ||
1bc09869 | 353 | if (elapsed_time_len == 0) |
2d0817d1 | 354 | return 0; |
7c657876 | 355 | |
2d0817d1 ACM |
356 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
357 | return -1; | |
7c657876 ACM |
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 | ||
1bc09869 | 365 | if (elapsed_time_len == 2) { |
60fe62e7 | 366 | const __be16 var16 = htons((u16)elapsed_time); |
1bc09869 IM |
367 | memcpy(to, &var16, 2); |
368 | } else { | |
60fe62e7 | 369 | const __be32 var32 = htonl(elapsed_time); |
1bc09869 IM |
370 | memcpy(to, &var32, 4); |
371 | } | |
7c657876 | 372 | |
2d0817d1 | 373 | return 0; |
7c657876 ACM |
374 | } |
375 | ||
d4b81ff7 | 376 | EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); |
7c657876 | 377 | |
1f4f0f64 | 378 | static int dccp_insert_option_timestamp(struct sk_buff *skb) |
7c657876 | 379 | { |
4c70f383 | 380 | __be32 now = htonl(dccp_timestamp()); |
1bc09869 IM |
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 | ||
a7d13fbf | 384 | return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now)); |
7c657876 ACM |
385 | } |
386 | ||
b4d4f7c7 GR |
387 | static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, |
388 | struct dccp_request_sock *dreq, | |
2d0817d1 | 389 | struct sk_buff *skb) |
7c657876 | 390 | { |
60fe62e7 | 391 | __be32 tstamp_echo; |
7c657876 | 392 | unsigned char *to; |
b4d4f7c7 GR |
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 | ||
b0e56780 ACM |
405 | elapsed_time_len = dccp_elapsed_time_len(elapsed_time); |
406 | len = 6 + elapsed_time_len; | |
407 | ||
2d0817d1 ACM |
408 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
409 | return -1; | |
7c657876 ACM |
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 | ||
7c657876 ACM |
417 | memcpy(to, &tstamp_echo, 4); |
418 | to += 4; | |
afe00251 | 419 | |
1bc09869 | 420 | if (elapsed_time_len == 2) { |
60fe62e7 | 421 | const __be16 var16 = htons((u16)elapsed_time); |
1bc09869 IM |
422 | memcpy(to, &var16, 2); |
423 | } else if (elapsed_time_len == 4) { | |
60fe62e7 | 424 | const __be32 var32 = htonl(elapsed_time); |
1bc09869 IM |
425 | memcpy(to, &var32, 4); |
426 | } | |
7c657876 | 427 | |
2d0817d1 | 428 | return 0; |
7c657876 ACM |
429 | } |
430 | ||
7d870936 GR |
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; | |
d83447f0 | 435 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
b3d14bff | 436 | const u16 buflen = dccp_ackvec_buflen(av); |
7d870936 | 437 | /* Figure out how many options do we need to represent the ackvec */ |
b3d14bff GR |
438 | const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN); |
439 | u16 len = buflen + 2 * nr_opts; | |
7d870936 GR |
440 | u8 i, nonce = 0; |
441 | const unsigned char *tail, *from; | |
442 | unsigned char *to; | |
443 | ||
d83447f0 GR |
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)); | |
7d870936 | 447 | return -1; |
d83447f0 GR |
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; | |
7d870936 GR |
463 | |
464 | to = skb_push(skb, len); | |
b3d14bff | 465 | len = buflen; |
7d870936 GR |
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 | */ | |
d83447f0 | 503 | if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce)) |
7d870936 GR |
504 | return -ENOBUFS; |
505 | return 0; | |
506 | } | |
507 | ||
d3710566 GR |
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 | ||
8c862c23 GR |
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 | * The last argument is used to construct Confirm options, where the preferred | |
531 | * value and the preference list appear separately (RFC 4340, 6.3.1). Preference | |
532 | * lists are kept such that the preferred entry is always first, so we only need | |
533 | * to copy twice, and avoid the overhead of cloning into a bigger array. | |
534 | */ | |
535 | int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, | |
536 | u8 *val, u8 len, bool repeat_first) | |
4829007c | 537 | { |
8c862c23 | 538 | u8 tot_len, *to; |
4829007c | 539 | |
8c862c23 GR |
540 | /* take the `Feature' field and possible repetition into account */ |
541 | if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) { | |
542 | DCCP_WARN("length %u for feature %u too large\n", len, feat); | |
4829007c | 543 | return -1; |
c2f42077 | 544 | } |
4829007c | 545 | |
8c862c23 | 546 | if (unlikely(val == NULL || len == 0)) |
3db1cd5c | 547 | len = repeat_first = false; |
8c862c23 GR |
548 | tot_len = 3 + repeat_first + len; |
549 | ||
550 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) { | |
551 | DCCP_WARN("packet too small for feature %d option!\n", feat); | |
552 | return -1; | |
553 | } | |
554 | DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len; | |
4829007c | 555 | |
8c862c23 | 556 | to = skb_push(skb, tot_len); |
410e27a4 | 557 | *to++ = type; |
8c862c23 | 558 | *to++ = tot_len; |
410e27a4 | 559 | *to++ = feat; |
4829007c | 560 | |
8c862c23 GR |
561 | if (repeat_first) |
562 | *to++ = *val; | |
410e27a4 GR |
563 | if (len) |
564 | memcpy(to, val, len); | |
d0440ee6 GR |
565 | return 0; |
566 | } | |
567 | ||
af3b867e GR |
568 | /* The length of all options needs to be a multiple of 4 (5.8) */ |
569 | static void dccp_insert_option_padding(struct sk_buff *skb) | |
570 | { | |
571 | int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; | |
572 | ||
573 | if (padding != 0) { | |
574 | padding = 4 - padding; | |
575 | memset(skb_push(skb, padding), 0, padding); | |
576 | DCCP_SKB_CB(skb)->dccpd_opt_len += padding; | |
577 | } | |
578 | } | |
579 | ||
2d0817d1 | 580 | int dccp_insert_options(struct sock *sk, struct sk_buff *skb) |
7c657876 ACM |
581 | { |
582 | struct dccp_sock *dp = dccp_sk(sk); | |
583 | ||
584 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; | |
585 | ||
4098dce5 | 586 | if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb)) |
2d0817d1 | 587 | return -1; |
7c657876 | 588 | |
8b7b6c75 GR |
589 | if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) { |
590 | ||
591 | /* Feature Negotiation */ | |
592 | if (dccp_feat_insert_opts(dp, NULL, skb)) | |
2d0817d1 | 593 | return -1; |
8b7b6c75 GR |
594 | |
595 | if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { | |
596 | /* | |
597 | * Obtain RTT sample from Request/Response exchange. | |
59b80802 | 598 | * This is currently used for TFRC initialisation. |
8b7b6c75 | 599 | */ |
a7d13fbf | 600 | if (dccp_insert_option_timestamp(skb)) |
8b7b6c75 GR |
601 | return -1; |
602 | ||
b3d14bff | 603 | } else if (dccp_ackvec_pending(sk) && |
8b7b6c75 GR |
604 | dccp_insert_option_ackvec(sk, skb)) { |
605 | return -1; | |
606 | } | |
7c657876 ACM |
607 | } |
608 | ||
507d37cf | 609 | if (dp->dccps_hc_rx_insert_options) { |
2d0817d1 ACM |
610 | if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) |
611 | return -1; | |
507d37cf ACM |
612 | dp->dccps_hc_rx_insert_options = 0; |
613 | } | |
7c657876 | 614 | |
b4d4f7c7 GR |
615 | if (dp->dccps_timestamp_echo != 0 && |
616 | dccp_insert_option_timestamp_echo(dp, NULL, skb)) | |
617 | return -1; | |
618 | ||
af3b867e GR |
619 | dccp_insert_option_padding(skb); |
620 | return 0; | |
621 | } | |
7c657876 | 622 | |
af3b867e GR |
623 | int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) |
624 | { | |
625 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; | |
7c657876 | 626 | |
8b7b6c75 GR |
627 | if (dccp_feat_insert_opts(NULL, dreq, skb)) |
628 | return -1; | |
629 | ||
59b80802 GR |
630 | /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */ |
631 | if (dccp_insert_option_timestamp(skb)) | |
632 | return -1; | |
633 | ||
af3b867e GR |
634 | if (dreq->dreq_timestamp_echo != 0 && |
635 | dccp_insert_option_timestamp_echo(NULL, dreq, skb)) | |
636 | return -1; | |
2d0817d1 | 637 | |
af3b867e | 638 | dccp_insert_option_padding(skb); |
2d0817d1 | 639 | return 0; |
7c657876 | 640 | } |