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 <iam4@cs.waikato.ac.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/config.h>
15 #include <linux/dccp.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/skbuff.h>
26 /* stores the default values for new connection. may be changed with sysctl */
27 static const struct dccp_options dccpo_default_values = {
28 .dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
29 .dccpo_rx_ccid = DCCPF_INITIAL_CCID,
30 .dccpo_tx_ccid = DCCPF_INITIAL_CCID,
31 .dccpo_ack_ratio = DCCPF_INITIAL_ACK_RATIO,
32 .dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
33 .dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
36 void dccp_options_init(struct dccp_options *dccpo)
38 memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
41 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
57 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
59 struct dccp_sock *dp = dccp_sk(sk);
60 #ifdef CONFIG_IP_DCCP_DEBUG
61 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
62 "CLIENT rx opt: " : "server rx opt: ";
64 const struct dccp_hdr *dh = dccp_hdr(skb);
65 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
66 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
67 unsigned char *opt_ptr = options;
68 const unsigned char *opt_end = (unsigned char *)dh +
70 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
71 unsigned char opt, len;
77 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_invalid_option;
91 goto out_invalid_option;
93 * Remove the type and len fields, leaving
100 if (opt_ptr > opt_end)
101 goto out_invalid_option;
107 case DCCPO_MANDATORY:
109 goto out_invalid_option;
112 case DCCPO_NDP_COUNT:
114 goto out_invalid_option;
116 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
117 dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
118 opt_recv->dccpor_ndp);
124 goto out_invalid_option;
125 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
128 * When there is a change error, change_recv is
129 * responsible for dealing with it. i.e. reply with an
131 * If the change was mandatory, then we need to die.
134 goto out_invalid_option;
136 case DCCPO_CONFIRM_L:
138 case DCCPO_CONFIRM_R:
140 goto out_invalid_option;
141 if (dccp_feat_confirm_recv(sk, opt, *value,
143 goto out_invalid_option;
145 case DCCPO_ACK_VECTOR_0:
146 case DCCPO_ACK_VECTOR_1:
147 if (pkt_type == DCCP_PKT_DATA)
150 if (dp->dccps_options.dccpo_send_ack_vector &&
151 dccp_ackvec_parse(sk, skb, opt, value, len))
152 goto out_invalid_option;
154 case DCCPO_TIMESTAMP:
156 goto out_invalid_option;
158 opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
160 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
161 dccp_timestamp(sk, &dp->dccps_timestamp_time);
163 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
164 debug_prefix, opt_recv->dccpor_timestamp,
166 DCCP_SKB_CB(skb)->dccpd_ack_seq);
168 case DCCPO_TIMESTAMP_ECHO:
169 if (len != 4 && len != 6 && len != 8)
170 goto out_invalid_option;
172 opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
174 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
176 opt_recv->dccpor_timestamp_echo,
179 DCCP_SKB_CB(skb)->dccpd_ack_seq);
186 elapsed_time = ntohs(*(u16 *)(value + 4));
188 elapsed_time = ntohl(*(u32 *)(value + 4));
190 /* Give precedence to the biggest ELAPSED_TIME */
191 if (elapsed_time > opt_recv->dccpor_elapsed_time)
192 opt_recv->dccpor_elapsed_time = elapsed_time;
194 case DCCPO_ELAPSED_TIME:
195 if (len != 2 && len != 4)
196 goto out_invalid_option;
198 if (pkt_type == DCCP_PKT_DATA)
202 elapsed_time = ntohs(*(u16 *)value);
204 elapsed_time = ntohl(*(u32 *)value);
206 if (elapsed_time > opt_recv->dccpor_elapsed_time)
207 opt_recv->dccpor_elapsed_time = elapsed_time;
209 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
213 * From draft-ietf-dccp-spec-11.txt:
215 * Option numbers 128 through 191 are for
216 * options sent from the HC-Sender to the
217 * HC-Receiver; option numbers 192 through 255
218 * are for options sent from the HC-Receiver to
222 const u16 idx = value - options;
224 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
227 goto out_invalid_option;
231 const u16 idx = value - options;
233 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
236 goto out_invalid_option;
240 pr_info("DCCP(%p): option %d(len=%d) not "
241 "implemented, ignoring\n",
246 if (opt != DCCPO_MANDATORY)
253 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
254 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
255 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
259 static void dccp_encode_value_var(const u32 value, unsigned char *to,
260 const unsigned int len)
263 *to++ = (value & 0xFF000000) >> 24;
265 *to++ = (value & 0xFF0000) >> 16;
267 *to++ = (value & 0xFF00) >> 8;
269 *to++ = (value & 0xFF);
272 static inline int dccp_ndp_len(const int ndp)
274 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
277 void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
278 const unsigned char option,
279 const void *value, const unsigned char len)
283 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
284 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
285 "%d option!\n", option);
289 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
291 to = skb_push(skb, len + 2);
295 memcpy(to, value, len);
298 EXPORT_SYMBOL_GPL(dccp_insert_option);
300 static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
302 struct dccp_sock *dp = dccp_sk(sk);
303 int ndp = dp->dccps_ndp_count;
305 if (dccp_non_data_packet(skb))
306 ++dp->dccps_ndp_count;
308 dp->dccps_ndp_count = 0;
312 const int ndp_len = dccp_ndp_len(ndp);
313 const int len = ndp_len + 2;
315 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
318 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
320 ptr = skb_push(skb, len);
321 *ptr++ = DCCPO_NDP_COUNT;
323 dccp_encode_value_var(ndp, ptr, ndp_len);
327 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
329 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
332 void dccp_insert_option_elapsed_time(struct sock *sk,
336 #ifdef CONFIG_IP_DCCP_DEBUG
337 struct dccp_sock *dp = dccp_sk(sk);
338 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
339 "CLIENT TX opt: " : "server TX opt: ";
341 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
342 const int len = 2 + elapsed_time_len;
345 if (elapsed_time_len == 0)
348 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
349 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
350 "insert elapsed time!\n");
354 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
356 to = skb_push(skb, len);
357 *to++ = DCCPO_ELAPSED_TIME;
360 if (elapsed_time_len == 2) {
361 const u16 var16 = htons((u16)elapsed_time);
362 memcpy(to, &var16, 2);
364 const u32 var32 = htonl(elapsed_time);
365 memcpy(to, &var32, 4);
368 dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
369 debug_prefix, elapsed_time,
371 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
374 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
376 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
378 const struct dccp_sock *dp = dccp_sk(sk);
381 tv->tv_sec -= dp->dccps_epoch.tv_sec;
382 tv->tv_usec -= dp->dccps_epoch.tv_usec;
384 while (tv->tv_usec < 0) {
386 tv->tv_usec += USEC_PER_SEC;
390 EXPORT_SYMBOL_GPL(dccp_timestamp);
392 void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
397 dccp_timestamp(sk, &tv);
398 now = timeval_usecs(&tv) / 10;
399 /* yes this will overflow but that is the point as we want a
400 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
403 dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
406 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
408 static void dccp_insert_option_timestamp_echo(struct sock *sk,
411 struct dccp_sock *dp = dccp_sk(sk);
412 #ifdef CONFIG_IP_DCCP_DEBUG
413 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
414 "CLIENT TX opt: " : "server TX opt: ";
419 int len, elapsed_time_len;
422 dccp_timestamp(sk, &now);
423 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
424 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
425 len = 6 + elapsed_time_len;
427 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
428 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
429 "timestamp echo!\n");
433 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
435 to = skb_push(skb, len);
436 *to++ = DCCPO_TIMESTAMP_ECHO;
439 tstamp_echo = htonl(dp->dccps_timestamp_echo);
440 memcpy(to, &tstamp_echo, 4);
443 if (elapsed_time_len == 2) {
444 const u16 var16 = htons((u16)elapsed_time);
445 memcpy(to, &var16, 2);
446 } else if (elapsed_time_len == 4) {
447 const u32 var32 = htonl(elapsed_time);
448 memcpy(to, &var32, 4);
451 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
452 debug_prefix, dp->dccps_timestamp_echo,
454 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
456 dp->dccps_timestamp_echo = 0;
457 dp->dccps_timestamp_time.tv_sec = 0;
458 dp->dccps_timestamp_time.tv_usec = 0;
461 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
466 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
467 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small"
468 " to insert feature %d option!\n", feat);
472 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
474 to = skb_push(skb, len + 3);
480 memcpy(to, val, len);
481 dccp_pr_debug("option %d feat %d len %d\n", type, feat, len);
486 static void dccp_insert_feat(struct sock *sk, struct sk_buff *skb)
488 struct dccp_sock *dp = dccp_sk(sk);
489 struct dccp_opt_pend *opt, *next;
492 /* confirm any options [NN opts] */
493 list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_conf,
495 dccp_insert_feat_opt(skb, opt->dccpop_type,
496 opt->dccpop_feat, opt->dccpop_val,
498 /* fear empty confirms */
500 kfree(opt->dccpop_val);
503 INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf);
505 /* see which features we need to send */
506 list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
508 /* see if we need to send any confirm */
509 if (opt->dccpop_sc) {
510 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
512 opt->dccpop_sc->dccpoc_val,
513 opt->dccpop_sc->dccpoc_len);
515 BUG_ON(!opt->dccpop_sc->dccpoc_val);
516 kfree(opt->dccpop_sc->dccpoc_val);
517 kfree(opt->dccpop_sc);
518 opt->dccpop_sc = NULL;
521 /* any option not confirmed, re-send it */
522 if (!opt->dccpop_conf) {
523 dccp_insert_feat_opt(skb, opt->dccpop_type,
524 opt->dccpop_feat, opt->dccpop_val,
531 * If this is the master listening sock, we don't set a timer on it. It
532 * should be fine because if the dude doesn't receive our RESPONSE
533 * [which will contain the CHANGE] he will send another REQUEST which
534 * will "retrnasmit" the change.
536 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
537 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
539 /* XXX don't reset the timer on re-transmissions. I.e. reset it
540 * only when sending new stuff i guess. Currently the timer
541 * never backs off because on re-transmission it just resets it!
543 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
544 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
548 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
550 struct dccp_sock *dp = dccp_sk(sk);
552 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
554 if (dp->dccps_options.dccpo_send_ndp_count)
555 dccp_insert_option_ndp(sk, skb);
557 if (!dccp_packet_without_ack(skb)) {
558 if (dp->dccps_options.dccpo_send_ack_vector &&
559 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec))
560 dccp_insert_option_ackvec(sk, skb);
561 if (dp->dccps_timestamp_echo != 0)
562 dccp_insert_option_timestamp_echo(sk, skb);
565 if (dp->dccps_hc_rx_insert_options) {
566 ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
567 dp->dccps_hc_rx_insert_options = 0;
569 if (dp->dccps_hc_tx_insert_options) {
570 ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
571 dp->dccps_hc_tx_insert_options = 0;
574 /* Feature negotiation */
575 switch(DCCP_SKB_CB(skb)->dccpd_type) {
576 /* Data packets can't do feat negotiation */
578 case DCCP_PKT_DATAACK:
581 dccp_insert_feat(sk, skb);
585 /* XXX: insert other options when appropriate */
587 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
588 /* The length of all options has to be a multiple of 4 */
589 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
592 padding = 4 - padding;
593 memset(skb_push(skb, padding), 0, padding);
594 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;