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_ack_ratio = DCCPF_INITIAL_ACK_RATIO;
30 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
31 int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT;
33 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
50 * dccp_parse_options - Parse DCCP options present in @skb
51 * @sk: client|server|listening dccp socket (when @dreq != NULL)
52 * @dreq: request socket to use during connection setup, or NULL
54 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
57 struct dccp_sock *dp = dccp_sk(sk);
58 const struct dccp_hdr *dh = dccp_hdr(skb);
59 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
60 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
61 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
62 unsigned char *opt_ptr = options;
63 const unsigned char *opt_end = (unsigned char *)dh +
65 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
66 unsigned char opt, len;
73 memset(opt_recv, 0, sizeof(*opt_recv));
76 while (opt_ptr != opt_end) {
81 /* Check if this isn't a single byte option */
82 if (opt > DCCPO_MAX_RESERVED) {
83 if (opt_ptr == opt_end)
84 goto out_invalid_option;
88 goto out_invalid_option;
90 * Remove the type and len fields, leaving
97 if (opt_ptr > opt_end)
98 goto out_invalid_option;
102 * CCID-Specific Options (from RFC 4340, sec. 10.3):
104 * Option numbers 128 through 191 are for options sent from the
105 * HC-Sender to the HC-Receiver; option numbers 192 through 255
106 * are for options sent from the HC-Receiver to the HC-Sender.
108 * CCID-specific options are ignored during connection setup, as
109 * negotiation may still be in progress (see RFC 4340, 10.3).
112 if (dreq != NULL && opt >= 128)
118 case DCCPO_MANDATORY:
120 goto out_invalid_option;
121 if (pkt_type != DCCP_PKT_DATA)
124 case DCCPO_NDP_COUNT:
126 goto out_invalid_option;
128 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
129 dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
130 opt_recv->dccpor_ndp);
135 if (pkt_type == DCCP_PKT_DATA)
138 goto out_invalid_option;
139 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
142 * When there is a change error, change_recv is
143 * responsible for dealing with it. i.e. reply with an
145 * If the change was mandatory, then we need to die.
148 goto out_invalid_option;
150 case DCCPO_CONFIRM_L:
152 case DCCPO_CONFIRM_R:
153 if (pkt_type == DCCP_PKT_DATA)
155 if (len < 2) /* FIXME this disallows empty confirm */
156 goto out_invalid_option;
157 if (dccp_feat_confirm_recv(sk, opt, *value,
159 goto out_invalid_option;
161 case DCCPO_ACK_VECTOR_0:
162 case DCCPO_ACK_VECTOR_1:
163 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
166 if (dccp_msk(sk)->dccpms_send_ack_vector &&
167 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
168 goto out_invalid_option;
170 case DCCPO_TIMESTAMP:
172 goto out_invalid_option;
174 * RFC 4340 13.1: "The precise time corresponding to
175 * Timestamp Value zero is not specified". We use
176 * zero to indicate absence of a meaningful timestamp.
178 opt_val = get_unaligned((__be32 *)value);
179 if (unlikely(opt_val == 0)) {
180 DCCP_WARN("Timestamp with zero value\n");
185 dreq->dreq_timestamp_echo = ntohl(opt_val);
186 dreq->dreq_timestamp_time = dccp_timestamp();
188 opt_recv->dccpor_timestamp =
189 dp->dccps_timestamp_echo = ntohl(opt_val);
190 dp->dccps_timestamp_time = dccp_timestamp();
192 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
193 dccp_role(sk), ntohl(opt_val),
195 DCCP_SKB_CB(skb)->dccpd_ack_seq);
197 case DCCPO_TIMESTAMP_ECHO:
198 if (len != 4 && len != 6 && len != 8)
199 goto out_invalid_option;
201 opt_val = get_unaligned((__be32 *)value);
202 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
204 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
205 "ackno=%llu", dccp_role(sk),
206 opt_recv->dccpor_timestamp_echo,
209 DCCP_SKB_CB(skb)->dccpd_ack_seq);
213 if (len == 4) { /* no elapsed time included */
214 dccp_pr_debug_cat("\n");
218 if (len == 6) { /* 2-byte elapsed time */
219 __be16 opt_val2 = get_unaligned((__be16 *)value);
220 elapsed_time = ntohs(opt_val2);
221 } else { /* 4-byte elapsed time */
222 opt_val = get_unaligned((__be32 *)value);
223 elapsed_time = ntohl(opt_val);
226 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
228 /* Give precedence to the biggest ELAPSED_TIME */
229 if (elapsed_time > opt_recv->dccpor_elapsed_time)
230 opt_recv->dccpor_elapsed_time = elapsed_time;
232 case DCCPO_ELAPSED_TIME:
233 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
237 __be16 opt_val2 = get_unaligned((__be16 *)value);
238 elapsed_time = ntohs(opt_val2);
239 } else if (len == 4) {
240 opt_val = get_unaligned((__be32 *)value);
241 elapsed_time = ntohl(opt_val);
243 goto out_invalid_option;
246 if (elapsed_time > opt_recv->dccpor_elapsed_time)
247 opt_recv->dccpor_elapsed_time = elapsed_time;
249 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
250 dccp_role(sk), elapsed_time);
253 const u16 idx = value - options;
255 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
258 goto out_invalid_option;
262 const u16 idx = value - options;
264 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
267 goto out_invalid_option;
271 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
272 "implemented, ignoring", sk, opt, len);
276 if (opt != DCCPO_MANDATORY)
280 /* mandatory was the last byte in option list -> reset connection */
282 goto out_invalid_option;
287 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
288 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
289 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
293 EXPORT_SYMBOL_GPL(dccp_parse_options);
295 static void dccp_encode_value_var(const u32 value, unsigned char *to,
296 const unsigned int len)
299 *to++ = (value & 0xFF000000) >> 24;
301 *to++ = (value & 0xFF0000) >> 16;
303 *to++ = (value & 0xFF00) >> 8;
305 *to++ = (value & 0xFF);
308 static inline int dccp_ndp_len(const int ndp)
310 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
313 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
314 const unsigned char option,
315 const void *value, const unsigned char len)
319 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
322 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
324 to = skb_push(skb, len + 2);
328 memcpy(to, value, len);
332 EXPORT_SYMBOL_GPL(dccp_insert_option);
334 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
336 struct dccp_sock *dp = dccp_sk(sk);
337 int ndp = dp->dccps_ndp_count;
339 if (dccp_non_data_packet(skb))
340 ++dp->dccps_ndp_count;
342 dp->dccps_ndp_count = 0;
346 const int ndp_len = dccp_ndp_len(ndp);
347 const int len = ndp_len + 2;
349 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
352 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
354 ptr = skb_push(skb, len);
355 *ptr++ = DCCPO_NDP_COUNT;
357 dccp_encode_value_var(ndp, ptr, ndp_len);
363 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
365 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
368 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
371 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
372 const int len = 2 + elapsed_time_len;
375 if (elapsed_time_len == 0)
378 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
381 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
383 to = skb_push(skb, len);
384 *to++ = DCCPO_ELAPSED_TIME;
387 if (elapsed_time_len == 2) {
388 const __be16 var16 = htons((u16)elapsed_time);
389 memcpy(to, &var16, 2);
391 const __be32 var32 = htonl(elapsed_time);
392 memcpy(to, &var32, 4);
398 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
400 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
402 __be32 now = htonl(dccp_timestamp());
403 /* yes this will overflow but that is the point as we want a
404 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
406 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
409 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
411 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
412 struct dccp_request_sock *dreq,
417 u32 elapsed_time, elapsed_time_len, len;
420 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
421 tstamp_echo = htonl(dreq->dreq_timestamp_echo);
422 dreq->dreq_timestamp_echo = 0;
424 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
425 tstamp_echo = htonl(dp->dccps_timestamp_echo);
426 dp->dccps_timestamp_echo = 0;
429 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
430 len = 6 + elapsed_time_len;
432 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
435 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
437 to = skb_push(skb, len);
438 *to++ = DCCPO_TIMESTAMP_ECHO;
441 memcpy(to, &tstamp_echo, 4);
444 if (elapsed_time_len == 2) {
445 const __be16 var16 = htons((u16)elapsed_time);
446 memcpy(to, &var16, 2);
447 } else if (elapsed_time_len == 4) {
448 const __be32 var32 = htonl(elapsed_time);
449 memcpy(to, &var32, 4);
455 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
460 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
461 DCCP_WARN("packet too small for feature %d option!\n", feat);
465 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
467 to = skb_push(skb, len + 3);
473 memcpy(to, val, len);
475 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
476 dccp_feat_typename(type),
477 dccp_feat_name(feat), feat, len);
481 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
483 struct dccp_sock *dp = dccp_sk(sk);
484 struct dccp_minisock *dmsk = dccp_msk(sk);
485 struct dccp_opt_pend *opt, *next;
488 /* confirm any options [NN opts] */
489 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
490 dccp_insert_feat_opt(skb, opt->dccpop_type,
491 opt->dccpop_feat, opt->dccpop_val,
493 /* fear empty confirms */
495 kfree(opt->dccpop_val);
498 INIT_LIST_HEAD(&dmsk->dccpms_conf);
500 /* see which features we need to send */
501 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
502 /* see if we need to send any confirm */
503 if (opt->dccpop_sc) {
504 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
506 opt->dccpop_sc->dccpoc_val,
507 opt->dccpop_sc->dccpoc_len);
509 BUG_ON(!opt->dccpop_sc->dccpoc_val);
510 kfree(opt->dccpop_sc->dccpoc_val);
511 kfree(opt->dccpop_sc);
512 opt->dccpop_sc = NULL;
515 /* any option not confirmed, re-send it */
516 if (!opt->dccpop_conf) {
517 dccp_insert_feat_opt(skb, opt->dccpop_type,
518 opt->dccpop_feat, opt->dccpop_val,
525 * If this is the master listening sock, we don't set a timer on it. It
526 * should be fine because if the dude doesn't receive our RESPONSE
527 * [which will contain the CHANGE] he will send another REQUEST which
528 * will "retrnasmit" the change.
530 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
531 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
533 /* XXX don't reset the timer on re-transmissions. I.e. reset it
534 * only when sending new stuff i guess. Currently the timer
535 * never backs off because on re-transmission it just resets it!
537 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
538 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
544 /* The length of all options needs to be a multiple of 4 (5.8) */
545 static void dccp_insert_option_padding(struct sk_buff *skb)
547 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
550 padding = 4 - padding;
551 memset(skb_push(skb, padding), 0, padding);
552 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
556 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
558 struct dccp_sock *dp = dccp_sk(sk);
559 struct dccp_minisock *dmsk = dccp_msk(sk);
561 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
563 if (dmsk->dccpms_send_ndp_count &&
564 dccp_insert_option_ndp(sk, skb))
567 if (!dccp_packet_without_ack(skb)) {
568 if (dmsk->dccpms_send_ack_vector &&
569 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
570 dccp_insert_option_ackvec(sk, skb))
574 if (dp->dccps_hc_rx_insert_options) {
575 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
577 dp->dccps_hc_rx_insert_options = 0;
580 /* Feature negotiation */
581 /* Data packets can't do feat negotiation */
582 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
583 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
584 dccp_insert_options_feat(sk, skb))
588 * Obtain RTT sample from Request/Response exchange.
589 * This is currently used in CCID 3 initialisation.
591 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
592 dccp_insert_option_timestamp(sk, skb))
595 if (dp->dccps_timestamp_echo != 0 &&
596 dccp_insert_option_timestamp_echo(dp, NULL, skb))
599 dccp_insert_option_padding(skb);
603 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
605 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
607 if (dreq->dreq_timestamp_echo != 0 &&
608 dccp_insert_option_timestamp_echo(NULL, dreq, skb))
611 dccp_insert_option_padding(skb);