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 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
27 int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID;
28 int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID;
29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
30 int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
32 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
36 if (len >= DCCP_OPTVAL_MAXLEN)
37 value += ((u64)*bf++) << 40;
39 value += ((u64)*bf++) << 32;
41 value += ((u64)*bf++) << 24;
43 value += ((u64)*bf++) << 16;
45 value += ((u64)*bf++) << 8;
53 * dccp_parse_options - Parse DCCP options present in @skb
54 * @sk: client|server|listening dccp socket (when @dreq != NULL)
55 * @dreq: request socket to use during connection setup, or NULL
57 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
60 struct dccp_sock *dp = dccp_sk(sk);
61 const struct dccp_hdr *dh = dccp_hdr(skb);
62 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
63 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
64 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
65 unsigned char *opt_ptr = options;
66 const unsigned char *opt_end = (unsigned char *)dh +
68 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
69 unsigned char opt, len;
76 memset(opt_recv, 0, sizeof(*opt_recv));
79 while (opt_ptr != opt_end) {
84 /* Check if this isn't a single byte option */
85 if (opt > DCCPO_MAX_RESERVED) {
86 if (opt_ptr == opt_end)
87 goto out_nonsensical_length;
91 goto out_nonsensical_length;
93 * Remove the type and len fields, leaving
100 if (opt_ptr > opt_end)
101 goto out_nonsensical_length;
105 * CCID-Specific Options (from RFC 4340, sec. 10.3):
107 * Option numbers 128 through 191 are for options sent from the
108 * HC-Sender to the HC-Receiver; option numbers 192 through 255
109 * are for options sent from the HC-Receiver to the HC-Sender.
111 * CCID-specific options are ignored during connection setup, as
112 * negotiation may still be in progress (see RFC 4340, 10.3).
113 * The same applies to Ack Vectors, as these depend on the CCID.
116 if (dreq != NULL && (opt >= 128 ||
117 opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
123 case DCCPO_MANDATORY:
125 goto out_invalid_option;
126 if (pkt_type != DCCP_PKT_DATA)
129 case DCCPO_NDP_COUNT:
131 goto out_invalid_option;
133 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
134 dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
135 (unsigned long long)opt_recv->dccpor_ndp);
140 if (pkt_type == DCCP_PKT_DATA)
143 goto out_invalid_option;
144 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
147 * When there is a change error, change_recv is
148 * responsible for dealing with it. i.e. reply with an
150 * If the change was mandatory, then we need to die.
153 goto out_invalid_option;
155 case DCCPO_CONFIRM_L:
157 case DCCPO_CONFIRM_R:
158 if (pkt_type == DCCP_PKT_DATA)
160 if (len < 2) /* FIXME this disallows empty confirm */
161 goto out_invalid_option;
162 if (dccp_feat_confirm_recv(sk, opt, *value,
164 goto out_invalid_option;
166 case DCCPO_ACK_VECTOR_0:
167 case DCCPO_ACK_VECTOR_1:
168 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
171 if (dccp_msk(sk)->dccpms_send_ack_vector &&
172 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
173 goto out_invalid_option;
175 case DCCPO_TIMESTAMP:
177 goto out_invalid_option;
179 * RFC 4340 13.1: "The precise time corresponding to
180 * Timestamp Value zero is not specified". We use
181 * zero to indicate absence of a meaningful timestamp.
183 opt_val = get_unaligned((__be32 *)value);
184 if (unlikely(opt_val == 0)) {
185 DCCP_WARN("Timestamp with zero value\n");
190 dreq->dreq_timestamp_echo = ntohl(opt_val);
191 dreq->dreq_timestamp_time = dccp_timestamp();
193 opt_recv->dccpor_timestamp =
194 dp->dccps_timestamp_echo = ntohl(opt_val);
195 dp->dccps_timestamp_time = dccp_timestamp();
197 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
198 dccp_role(sk), ntohl(opt_val),
200 DCCP_SKB_CB(skb)->dccpd_ack_seq);
202 case DCCPO_TIMESTAMP_ECHO:
203 if (len != 4 && len != 6 && len != 8)
204 goto out_invalid_option;
206 opt_val = get_unaligned((__be32 *)value);
207 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
209 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
210 "ackno=%llu", dccp_role(sk),
211 opt_recv->dccpor_timestamp_echo,
214 DCCP_SKB_CB(skb)->dccpd_ack_seq);
218 if (len == 4) { /* no elapsed time included */
219 dccp_pr_debug_cat("\n");
223 if (len == 6) { /* 2-byte elapsed time */
224 __be16 opt_val2 = get_unaligned((__be16 *)value);
225 elapsed_time = ntohs(opt_val2);
226 } else { /* 4-byte elapsed time */
227 opt_val = get_unaligned((__be32 *)value);
228 elapsed_time = ntohl(opt_val);
231 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
233 /* Give precedence to the biggest ELAPSED_TIME */
234 if (elapsed_time > opt_recv->dccpor_elapsed_time)
235 opt_recv->dccpor_elapsed_time = elapsed_time;
237 case DCCPO_ELAPSED_TIME:
238 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
242 __be16 opt_val2 = get_unaligned((__be16 *)value);
243 elapsed_time = ntohs(opt_val2);
244 } else if (len == 4) {
245 opt_val = get_unaligned((__be32 *)value);
246 elapsed_time = ntohl(opt_val);
248 goto out_invalid_option;
251 if (elapsed_time > opt_recv->dccpor_elapsed_time)
252 opt_recv->dccpor_elapsed_time = elapsed_time;
254 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
255 dccp_role(sk), elapsed_time);
258 const u16 idx = value - options;
260 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
263 goto out_invalid_option;
267 const u16 idx = value - options;
269 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
272 goto out_invalid_option;
276 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
277 "implemented, ignoring", sk, opt, len);
281 if (opt != DCCPO_MANDATORY)
285 /* mandatory was the last byte in option list -> reset connection */
287 goto out_invalid_option;
289 out_nonsensical_length:
290 /* RFC 4340, 5.8: ignore option and all remaining option space */
294 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
295 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
296 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
297 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
298 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
299 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
303 EXPORT_SYMBOL_GPL(dccp_parse_options);
305 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
307 if (len >= DCCP_OPTVAL_MAXLEN)
308 *to++ = (value & 0xFF0000000000ull) >> 40;
310 *to++ = (value & 0xFF00000000ull) >> 32;
312 *to++ = (value & 0xFF000000) >> 24;
314 *to++ = (value & 0xFF0000) >> 16;
316 *to++ = (value & 0xFF00) >> 8;
318 *to++ = (value & 0xFF);
321 static inline u8 dccp_ndp_len(const u64 ndp)
323 if (likely(ndp <= 0xFF))
325 return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
328 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
329 const unsigned char option,
330 const void *value, const unsigned char len)
334 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
337 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
339 to = skb_push(skb, len + 2);
343 memcpy(to, value, len);
347 EXPORT_SYMBOL_GPL(dccp_insert_option);
349 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
351 struct dccp_sock *dp = dccp_sk(sk);
352 u64 ndp = dp->dccps_ndp_count;
354 if (dccp_non_data_packet(skb))
355 ++dp->dccps_ndp_count;
357 dp->dccps_ndp_count = 0;
361 const int ndp_len = dccp_ndp_len(ndp);
362 const int len = ndp_len + 2;
364 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
367 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
369 ptr = skb_push(skb, len);
370 *ptr++ = DCCPO_NDP_COUNT;
372 dccp_encode_value_var(ndp, ptr, ndp_len);
378 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
380 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
383 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
386 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
387 const int len = 2 + elapsed_time_len;
390 if (elapsed_time_len == 0)
393 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
396 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
398 to = skb_push(skb, len);
399 *to++ = DCCPO_ELAPSED_TIME;
402 if (elapsed_time_len == 2) {
403 const __be16 var16 = htons((u16)elapsed_time);
404 memcpy(to, &var16, 2);
406 const __be32 var32 = htonl(elapsed_time);
407 memcpy(to, &var32, 4);
413 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
415 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
417 __be32 now = htonl(dccp_timestamp());
418 /* yes this will overflow but that is the point as we want a
419 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
421 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
424 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
426 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
427 struct dccp_request_sock *dreq,
432 u32 elapsed_time, elapsed_time_len, len;
435 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
436 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
437 dreq->dreq_timestamp_echo = 0;
439 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
440 tstamp_echo = htonl(dp->dccps_timestamp_echo);
441 dp->dccps_timestamp_echo = 0;
444 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
445 len = 6 + elapsed_time_len;
447 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
450 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
452 to = skb_push(skb, len);
453 *to++ = DCCPO_TIMESTAMP_ECHO;
456 memcpy(to, &tstamp_echo, 4);
459 if (elapsed_time_len == 2) {
460 const __be16 var16 = htons((u16)elapsed_time);
461 memcpy(to, &var16, 2);
462 } else if (elapsed_time_len == 4) {
463 const __be32 var32 = htonl(elapsed_time);
464 memcpy(to, &var32, 4);
471 * dccp_insert_option_mandatory - Mandatory option (5.8.2)
472 * Note that since we are using skb_push, this function needs to be called
473 * _after_ inserting the option it is supposed to influence (stack order).
475 int dccp_insert_option_mandatory(struct sk_buff *skb)
477 if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
480 DCCP_SKB_CB(skb)->dccpd_opt_len++;
481 *skb_push(skb, 1) = DCCPO_MANDATORY;
485 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
490 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
491 DCCP_WARN("packet too small for feature %d option!\n", feat);
495 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
497 to = skb_push(skb, len + 3);
503 memcpy(to, val, len);
505 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
506 dccp_feat_typename(type),
507 dccp_feat_name(feat), feat, len);
511 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
513 struct dccp_minisock *dmsk = dccp_msk(sk);
514 struct dccp_opt_pend *opt, *next;
517 /* confirm any options [NN opts] */
518 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
519 dccp_insert_feat_opt(skb, opt->dccpop_type,
520 opt->dccpop_feat, opt->dccpop_val,
522 /* fear empty confirms */
524 kfree(opt->dccpop_val);
527 INIT_LIST_HEAD(&dmsk->dccpms_conf);
529 /* see which features we need to send */
530 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
531 /* see if we need to send any confirm */
532 if (opt->dccpop_sc) {
533 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
535 opt->dccpop_sc->dccpoc_val,
536 opt->dccpop_sc->dccpoc_len);
538 BUG_ON(!opt->dccpop_sc->dccpoc_val);
539 kfree(opt->dccpop_sc->dccpoc_val);
540 kfree(opt->dccpop_sc);
541 opt->dccpop_sc = NULL;
544 /* any option not confirmed, re-send it */
545 if (!opt->dccpop_conf) {
546 dccp_insert_feat_opt(skb, opt->dccpop_type,
547 opt->dccpop_feat, opt->dccpop_val,
556 /* The length of all options needs to be a multiple of 4 (5.8) */
557 static void dccp_insert_option_padding(struct sk_buff *skb)
559 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
562 padding = 4 - padding;
563 memset(skb_push(skb, padding), 0, padding);
564 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
568 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
570 struct dccp_sock *dp = dccp_sk(sk);
571 struct dccp_minisock *dmsk = dccp_msk(sk);
573 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
575 if (dmsk->dccpms_send_ndp_count &&
576 dccp_insert_option_ndp(sk, skb))
579 if (!dccp_packet_without_ack(skb)) {
580 if (dmsk->dccpms_send_ack_vector &&
581 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
582 dccp_insert_option_ackvec(sk, skb))
586 if (dp->dccps_hc_rx_insert_options) {
587 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
589 dp->dccps_hc_rx_insert_options = 0;
592 /* Feature negotiation */
593 /* Data packets can't do feat negotiation */
594 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
595 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
596 dccp_insert_options_feat(sk, skb))
600 * Obtain RTT sample from Request/Response exchange.
601 * This is currently used in CCID 3 initialisation.
603 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
604 dccp_insert_option_timestamp(sk, skb))
607 if (dp->dccps_timestamp_echo != 0 &&
608 dccp_insert_option_timestamp_echo(dp, NULL, skb))
611 dccp_insert_option_padding(skb);
615 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
617 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
619 if (dreq->dreq_timestamp_echo != 0 &&
620 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
623 dccp_insert_option_padding(skb);