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 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
49 * dccp_parse_options - Parse DCCP options present in @skb
50 * @sk: client|server|listening dccp socket (when @dreq != NULL)
51 * @dreq: request socket to use during connection setup, or NULL
53 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
56 struct dccp_sock *dp = dccp_sk(sk);
57 const struct dccp_hdr *dh = dccp_hdr(skb);
58 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
59 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
60 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
61 unsigned char *opt_ptr = options;
62 const unsigned char *opt_end = (unsigned char *)dh +
64 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
65 unsigned char opt, len;
72 memset(opt_recv, 0, sizeof(*opt_recv));
75 while (opt_ptr != opt_end) {
80 /* Check if this isn't a single byte option */
81 if (opt > DCCPO_MAX_RESERVED) {
82 if (opt_ptr == opt_end)
83 goto out_nonsensical_length;
87 goto out_nonsensical_length;
89 * Remove the type and len fields, leaving
96 if (opt_ptr > opt_end)
97 goto out_nonsensical_length;
101 * CCID-Specific Options (from RFC 4340, sec. 10.3):
103 * Option numbers 128 through 191 are for options sent from the
104 * HC-Sender to the HC-Receiver; option numbers 192 through 255
105 * are for options sent from the HC-Receiver to the HC-Sender.
107 * CCID-specific options are ignored during connection setup, as
108 * negotiation may still be in progress (see RFC 4340, 10.3).
109 * The same applies to Ack Vectors, as these depend on the CCID.
112 if (dreq != NULL && (opt >= 128 ||
113 opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
119 case DCCPO_MANDATORY:
121 goto out_invalid_option;
122 if (pkt_type != DCCP_PKT_DATA)
125 case DCCPO_NDP_COUNT:
127 goto out_invalid_option;
129 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
130 dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
131 (unsigned long long)opt_recv->dccpor_ndp);
136 if (pkt_type == DCCP_PKT_DATA)
139 goto out_invalid_option;
140 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
143 * When there is a change error, change_recv is
144 * responsible for dealing with it. i.e. reply with an
146 * If the change was mandatory, then we need to die.
149 goto out_invalid_option;
151 case DCCPO_CONFIRM_L:
153 case DCCPO_CONFIRM_R:
154 if (pkt_type == DCCP_PKT_DATA)
156 if (len < 2) /* FIXME this disallows empty confirm */
157 goto out_invalid_option;
158 if (dccp_feat_confirm_recv(sk, opt, *value,
160 goto out_invalid_option;
162 case DCCPO_ACK_VECTOR_0:
163 case DCCPO_ACK_VECTOR_1:
164 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
167 if (dccp_msk(sk)->dccpms_send_ack_vector &&
168 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
169 goto out_invalid_option;
171 case DCCPO_TIMESTAMP:
173 goto out_invalid_option;
175 * RFC 4340 13.1: "The precise time corresponding to
176 * Timestamp Value zero is not specified". We use
177 * zero to indicate absence of a meaningful timestamp.
179 opt_val = get_unaligned((__be32 *)value);
180 if (unlikely(opt_val == 0)) {
181 DCCP_WARN("Timestamp with zero value\n");
186 dreq->dreq_timestamp_echo = ntohl(opt_val);
187 dreq->dreq_timestamp_time = dccp_timestamp();
189 opt_recv->dccpor_timestamp =
190 dp->dccps_timestamp_echo = ntohl(opt_val);
191 dp->dccps_timestamp_time = dccp_timestamp();
193 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
194 dccp_role(sk), ntohl(opt_val),
196 DCCP_SKB_CB(skb)->dccpd_ack_seq);
198 case DCCPO_TIMESTAMP_ECHO:
199 if (len != 4 && len != 6 && len != 8)
200 goto out_invalid_option;
202 opt_val = get_unaligned((__be32 *)value);
203 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
205 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
206 "ackno=%llu", dccp_role(sk),
207 opt_recv->dccpor_timestamp_echo,
210 DCCP_SKB_CB(skb)->dccpd_ack_seq);
214 if (len == 4) { /* no elapsed time included */
215 dccp_pr_debug_cat("\n");
219 if (len == 6) { /* 2-byte elapsed time */
220 __be16 opt_val2 = get_unaligned((__be16 *)value);
221 elapsed_time = ntohs(opt_val2);
222 } else { /* 4-byte elapsed time */
223 opt_val = get_unaligned((__be32 *)value);
224 elapsed_time = ntohl(opt_val);
227 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
229 /* Give precedence to the biggest ELAPSED_TIME */
230 if (elapsed_time > opt_recv->dccpor_elapsed_time)
231 opt_recv->dccpor_elapsed_time = elapsed_time;
233 case DCCPO_ELAPSED_TIME:
234 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
238 __be16 opt_val2 = get_unaligned((__be16 *)value);
239 elapsed_time = ntohs(opt_val2);
240 } else if (len == 4) {
241 opt_val = get_unaligned((__be32 *)value);
242 elapsed_time = ntohl(opt_val);
244 goto out_invalid_option;
247 if (elapsed_time > opt_recv->dccpor_elapsed_time)
248 opt_recv->dccpor_elapsed_time = elapsed_time;
250 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
251 dccp_role(sk), elapsed_time);
254 const u16 idx = value - options;
256 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
259 goto out_invalid_option;
263 const u16 idx = value - options;
265 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
268 goto out_invalid_option;
272 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
273 "implemented, ignoring", sk, opt, len);
277 if (opt != DCCPO_MANDATORY)
281 /* mandatory was the last byte in option list -> reset connection */
283 goto out_invalid_option;
285 out_nonsensical_length:
286 /* RFC 4340, 5.8: ignore option and all remaining option space */
290 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
291 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
292 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
293 DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
294 DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
295 DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
299 EXPORT_SYMBOL_GPL(dccp_parse_options);
301 static void dccp_encode_value_var(const u32 value, unsigned char *to,
302 const unsigned int len)
305 *to++ = (value & 0xFF000000) >> 24;
307 *to++ = (value & 0xFF0000) >> 16;
309 *to++ = (value & 0xFF00) >> 8;
311 *to++ = (value & 0xFF);
314 static inline u8 dccp_ndp_len(const u64 ndp)
316 if (likely(ndp <= 0xFF))
318 return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
321 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
322 const unsigned char option,
323 const void *value, const unsigned char len)
327 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
330 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
332 to = skb_push(skb, len + 2);
336 memcpy(to, value, len);
340 EXPORT_SYMBOL_GPL(dccp_insert_option);
342 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
344 struct dccp_sock *dp = dccp_sk(sk);
345 u64 ndp = dp->dccps_ndp_count;
347 if (dccp_non_data_packet(skb))
348 ++dp->dccps_ndp_count;
350 dp->dccps_ndp_count = 0;
354 const int ndp_len = dccp_ndp_len(ndp);
355 const int len = ndp_len + 2;
357 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
360 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
362 ptr = skb_push(skb, len);
363 *ptr++ = DCCPO_NDP_COUNT;
365 dccp_encode_value_var(ndp, ptr, ndp_len);
371 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
373 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
376 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
379 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
380 const int len = 2 + elapsed_time_len;
383 if (elapsed_time_len == 0)
386 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
389 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
391 to = skb_push(skb, len);
392 *to++ = DCCPO_ELAPSED_TIME;
395 if (elapsed_time_len == 2) {
396 const __be16 var16 = htons((u16)elapsed_time);
397 memcpy(to, &var16, 2);
399 const __be32 var32 = htonl(elapsed_time);
400 memcpy(to, &var32, 4);
406 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
408 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
410 __be32 now = htonl(dccp_timestamp());
411 /* yes this will overflow but that is the point as we want a
412 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
414 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
417 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
419 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
420 struct dccp_request_sock *dreq,
425 u32 elapsed_time, elapsed_time_len, len;
428 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
429 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
430 dreq->dreq_timestamp_echo = 0;
432 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
433 tstamp_echo = htonl(dp->dccps_timestamp_echo);
434 dp->dccps_timestamp_echo = 0;
437 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
438 len = 6 + elapsed_time_len;
440 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
443 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
445 to = skb_push(skb, len);
446 *to++ = DCCPO_TIMESTAMP_ECHO;
449 memcpy(to, &tstamp_echo, 4);
452 if (elapsed_time_len == 2) {
453 const __be16 var16 = htons((u16)elapsed_time);
454 memcpy(to, &var16, 2);
455 } else if (elapsed_time_len == 4) {
456 const __be32 var32 = htonl(elapsed_time);
457 memcpy(to, &var32, 4);
463 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
468 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
469 DCCP_WARN("packet too small for feature %d option!\n", feat);
473 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
475 to = skb_push(skb, len + 3);
481 memcpy(to, val, len);
483 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
484 dccp_feat_typename(type),
485 dccp_feat_name(feat), feat, len);
489 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
491 struct dccp_minisock *dmsk = dccp_msk(sk);
492 struct dccp_opt_pend *opt, *next;
495 /* confirm any options [NN opts] */
496 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
497 dccp_insert_feat_opt(skb, opt->dccpop_type,
498 opt->dccpop_feat, opt->dccpop_val,
500 /* fear empty confirms */
502 kfree(opt->dccpop_val);
505 INIT_LIST_HEAD(&dmsk->dccpms_conf);
507 /* see which features we need to send */
508 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
509 /* see if we need to send any confirm */
510 if (opt->dccpop_sc) {
511 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
513 opt->dccpop_sc->dccpoc_val,
514 opt->dccpop_sc->dccpoc_len);
516 BUG_ON(!opt->dccpop_sc->dccpoc_val);
517 kfree(opt->dccpop_sc->dccpoc_val);
518 kfree(opt->dccpop_sc);
519 opt->dccpop_sc = NULL;
522 /* any option not confirmed, re-send it */
523 if (!opt->dccpop_conf) {
524 dccp_insert_feat_opt(skb, opt->dccpop_type,
525 opt->dccpop_feat, opt->dccpop_val,
534 /* The length of all options needs to be a multiple of 4 (5.8) */
535 static void dccp_insert_option_padding(struct sk_buff *skb)
537 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
540 padding = 4 - padding;
541 memset(skb_push(skb, padding), 0, padding);
542 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
546 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
548 struct dccp_sock *dp = dccp_sk(sk);
549 struct dccp_minisock *dmsk = dccp_msk(sk);
551 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
553 if (dmsk->dccpms_send_ndp_count &&
554 dccp_insert_option_ndp(sk, skb))
557 if (!dccp_packet_without_ack(skb)) {
558 if (dmsk->dccpms_send_ack_vector &&
559 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
560 dccp_insert_option_ackvec(sk, skb))
564 if (dp->dccps_hc_rx_insert_options) {
565 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
567 dp->dccps_hc_rx_insert_options = 0;
570 /* Feature negotiation */
571 /* Data packets can't do feat negotiation */
572 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
573 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
574 dccp_insert_options_feat(sk, skb))
578 * Obtain RTT sample from Request/Response exchange.
579 * This is currently used in CCID 3 initialisation.
581 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
582 dccp_insert_option_timestamp(sk, skb))
585 if (dp->dccps_timestamp_echo != 0 &&
586 dccp_insert_option_timestamp_echo(dp, NULL, skb))
589 dccp_insert_option_padding(skb);
593 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
595 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
597 if (dreq->dreq_timestamp_echo != 0 &&
598 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
601 dccp_insert_option_padding(skb);