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>
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.
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>
26 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
30 if (len >= DCCP_OPTVAL_MAXLEN)
31 value += ((u64)*bf++) << 40;
33 value += ((u64)*bf++) << 32;
35 value += ((u64)*bf++) << 24;
37 value += ((u64)*bf++) << 16;
39 value += ((u64)*bf++) << 8;
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
51 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
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 +
62 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
63 unsigned char opt, len;
70 memset(opt_recv, 0, sizeof(*opt_recv));
73 while (opt_ptr != opt_end) {
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;
85 goto out_nonsensical_length;
87 * Remove the type and len fields, leaving
94 if (opt_ptr > opt_end)
95 goto out_nonsensical_length;
99 * CCID-specific options are ignored during connection setup, as
100 * negotiation may still be in progress (see RFC 4340, 10.3).
101 * The same applies to Ack Vectors, as these depend on the CCID.
103 if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC ||
104 opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
110 case DCCPO_MANDATORY:
112 goto out_invalid_option;
113 if (pkt_type != DCCP_PKT_DATA)
116 case DCCPO_NDP_COUNT:
118 goto out_invalid_option;
120 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
121 dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
122 (unsigned long long)opt_recv->dccpor_ndp);
124 case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
125 if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
127 rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
128 *value, value + 1, len - 1);
130 goto out_featneg_failed;
132 case DCCPO_ACK_VECTOR_0:
133 case DCCPO_ACK_VECTOR_1:
134 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
136 if (dp->dccps_hc_rx_ackvec != NULL &&
137 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
138 goto out_invalid_option;
140 case DCCPO_TIMESTAMP:
142 goto out_invalid_option;
144 * RFC 4340 13.1: "The precise time corresponding to
145 * Timestamp Value zero is not specified". We use
146 * zero to indicate absence of a meaningful timestamp.
148 opt_val = get_unaligned((__be32 *)value);
149 if (unlikely(opt_val == 0)) {
150 DCCP_WARN("Timestamp with zero value\n");
155 dreq->dreq_timestamp_echo = ntohl(opt_val);
156 dreq->dreq_timestamp_time = dccp_timestamp();
158 opt_recv->dccpor_timestamp =
159 dp->dccps_timestamp_echo = ntohl(opt_val);
160 dp->dccps_timestamp_time = dccp_timestamp();
162 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
163 dccp_role(sk), ntohl(opt_val),
165 DCCP_SKB_CB(skb)->dccpd_ack_seq);
166 /* schedule an Ack in case this sender is quiescent */
167 inet_csk_schedule_ack(sk);
169 case DCCPO_TIMESTAMP_ECHO:
170 if (len != 4 && len != 6 && len != 8)
171 goto out_invalid_option;
173 opt_val = get_unaligned((__be32 *)value);
174 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
176 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
177 "ackno=%llu", dccp_role(sk),
178 opt_recv->dccpor_timestamp_echo,
181 DCCP_SKB_CB(skb)->dccpd_ack_seq);
185 if (len == 4) { /* no elapsed time included */
186 dccp_pr_debug_cat("\n");
190 if (len == 6) { /* 2-byte elapsed time */
191 __be16 opt_val2 = get_unaligned((__be16 *)value);
192 elapsed_time = ntohs(opt_val2);
193 } else { /* 4-byte elapsed time */
194 opt_val = get_unaligned((__be32 *)value);
195 elapsed_time = ntohl(opt_val);
198 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
200 /* Give precedence to the biggest ELAPSED_TIME */
201 if (elapsed_time > opt_recv->dccpor_elapsed_time)
202 opt_recv->dccpor_elapsed_time = elapsed_time;
204 case DCCPO_ELAPSED_TIME:
205 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
209 __be16 opt_val2 = get_unaligned((__be16 *)value);
210 elapsed_time = ntohs(opt_val2);
211 } else if (len == 4) {
212 opt_val = get_unaligned((__be32 *)value);
213 elapsed_time = ntohl(opt_val);
215 goto out_invalid_option;
218 if (elapsed_time > opt_recv->dccpor_elapsed_time)
219 opt_recv->dccpor_elapsed_time = elapsed_time;
221 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
222 dccp_role(sk), elapsed_time);
224 case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC:
225 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
226 pkt_type, opt, value, len))
227 goto out_invalid_option;
229 case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
230 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
231 pkt_type, opt, value, len))
232 goto out_invalid_option;
235 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
236 "implemented, ignoring", sk, opt, len);
240 if (opt != DCCPO_MANDATORY)
244 /* mandatory was the last byte in option list -> reset connection */
246 goto out_invalid_option;
248 out_nonsensical_length:
249 /* RFC 4340, 5.8: ignore option and all remaining option space */
253 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
254 rc = DCCP_RESET_CODE_OPTION_ERROR;
256 DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
257 DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
258 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
259 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
260 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
264 EXPORT_SYMBOL_GPL(dccp_parse_options);
266 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
268 if (len >= DCCP_OPTVAL_MAXLEN)
269 *to++ = (value & 0xFF0000000000ull) >> 40;
271 *to++ = (value & 0xFF00000000ull) >> 32;
273 *to++ = (value & 0xFF000000) >> 24;
275 *to++ = (value & 0xFF0000) >> 16;
277 *to++ = (value & 0xFF00) >> 8;
279 *to++ = (value & 0xFF);
282 static inline u8 dccp_ndp_len(const u64 ndp)
284 if (likely(ndp <= 0xFF))
286 return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
289 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
290 const unsigned char option,
291 const void *value, const unsigned char len)
295 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
298 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
300 to = skb_push(skb, len + 2);
304 memcpy(to, value, len);
308 EXPORT_SYMBOL_GPL(dccp_insert_option);
310 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
312 struct dccp_sock *dp = dccp_sk(sk);
313 u64 ndp = dp->dccps_ndp_count;
315 if (dccp_non_data_packet(skb))
316 ++dp->dccps_ndp_count;
318 dp->dccps_ndp_count = 0;
322 const int ndp_len = dccp_ndp_len(ndp);
323 const int len = ndp_len + 2;
325 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
328 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
330 ptr = skb_push(skb, len);
331 *ptr++ = DCCPO_NDP_COUNT;
333 dccp_encode_value_var(ndp, ptr, ndp_len);
339 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
341 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
344 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
347 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
348 const int len = 2 + elapsed_time_len;
351 if (elapsed_time_len == 0)
354 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
357 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
359 to = skb_push(skb, len);
360 *to++ = DCCPO_ELAPSED_TIME;
363 if (elapsed_time_len == 2) {
364 const __be16 var16 = htons((u16)elapsed_time);
365 memcpy(to, &var16, 2);
367 const __be32 var32 = htonl(elapsed_time);
368 memcpy(to, &var32, 4);
374 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
376 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
378 __be32 now = htonl(dccp_timestamp());
379 /* yes this will overflow but that is the point as we want a
380 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
382 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
385 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
387 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
388 struct dccp_request_sock *dreq,
393 u32 elapsed_time, elapsed_time_len, len;
396 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
397 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
398 dreq->dreq_timestamp_echo = 0;
400 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
401 tstamp_echo = htonl(dp->dccps_timestamp_echo);
402 dp->dccps_timestamp_echo = 0;
405 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
406 len = 6 + elapsed_time_len;
408 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
411 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
413 to = skb_push(skb, len);
414 *to++ = DCCPO_TIMESTAMP_ECHO;
417 memcpy(to, &tstamp_echo, 4);
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);
432 * dccp_insert_option_mandatory - Mandatory option (5.8.2)
433 * Note that since we are using skb_push, this function needs to be called
434 * _after_ inserting the option it is supposed to influence (stack order).
436 int dccp_insert_option_mandatory(struct sk_buff *skb)
438 if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
441 DCCP_SKB_CB(skb)->dccpd_opt_len++;
442 *skb_push(skb, 1) = DCCPO_MANDATORY;
447 * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
448 * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
449 * @feat: one out of %dccp_feature_numbers
450 * @val: NN value or SP array (preferred element first) to copy
451 * @len: true length of @val in bytes (excluding first element repetition)
452 * @repeat_first: whether to copy the first element of @val twice
453 * The last argument is used to construct Confirm options, where the preferred
454 * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
455 * lists are kept such that the preferred entry is always first, so we only need
456 * to copy twice, and avoid the overhead of cloning into a bigger array.
458 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
459 u8 *val, u8 len, bool repeat_first)
463 /* take the `Feature' field and possible repetition into account */
464 if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
465 DCCP_WARN("length %u for feature %u too large\n", len, feat);
469 if (unlikely(val == NULL || len == 0))
470 len = repeat_first = 0;
471 tot_len = 3 + repeat_first + len;
473 if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
474 DCCP_WARN("packet too small for feature %d option!\n", feat);
477 DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
479 to = skb_push(skb, tot_len);
487 memcpy(to, val, len);
491 /* The length of all options needs to be a multiple of 4 (5.8) */
492 static void dccp_insert_option_padding(struct sk_buff *skb)
494 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
497 padding = 4 - padding;
498 memset(skb_push(skb, padding), 0, padding);
499 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
503 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
505 struct dccp_sock *dp = dccp_sk(sk);
507 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
509 if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
512 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
514 /* Feature Negotiation */
515 if (dccp_feat_insert_opts(dp, NULL, skb))
518 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
520 * Obtain RTT sample from Request/Response exchange.
521 * This is currently used in CCID 3 initialisation.
523 if (dccp_insert_option_timestamp(sk, skb))
526 } else if (dp->dccps_hc_rx_ackvec != NULL &&
527 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
528 dccp_insert_option_ackvec(sk, skb)) {
533 if (dp->dccps_hc_rx_insert_options) {
534 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
536 dp->dccps_hc_rx_insert_options = 0;
539 if (dp->dccps_timestamp_echo != 0 &&
540 dccp_insert_option_timestamp_echo(dp, NULL, skb))
543 dccp_insert_option_padding(skb);
547 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
549 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
551 if (dccp_feat_insert_opts(NULL, dreq, skb))
554 if (dreq->dreq_timestamp_echo != 0 &&
555 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
558 dccp_insert_option_padding(skb);