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);
136 goto out_invalid_option;
137 rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
140 * When there is a change error, change_recv is
141 * responsible for dealing with it. i.e. reply with an
143 * If the change was mandatory, then we need to die.
146 goto out_invalid_option;
148 case DCCPO_CONFIRM_L:
150 case DCCPO_CONFIRM_R:
152 goto out_invalid_option;
153 if (dccp_feat_confirm_recv(sk, opt, *value,
155 goto out_invalid_option;
157 case DCCPO_ACK_VECTOR_0:
158 case DCCPO_ACK_VECTOR_1:
159 if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
162 if (dccp_msk(sk)->dccpms_send_ack_vector &&
163 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
164 goto out_invalid_option;
166 case DCCPO_TIMESTAMP:
168 goto out_invalid_option;
170 opt_val = get_unaligned((__be32 *)value);
171 opt_recv->dccpor_timestamp = ntohl(opt_val);
173 /* FIXME: if dreq != NULL, don't store this on listening socket */
174 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
175 dp->dccps_timestamp_time = ktime_get_real();
177 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
178 dccp_role(sk), opt_recv->dccpor_timestamp,
180 DCCP_SKB_CB(skb)->dccpd_ack_seq);
182 case DCCPO_TIMESTAMP_ECHO:
183 if (len != 4 && len != 6 && len != 8)
184 goto out_invalid_option;
186 opt_val = get_unaligned((__be32 *)value);
187 opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
189 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
190 "ackno=%llu", dccp_role(sk),
191 opt_recv->dccpor_timestamp_echo,
194 DCCP_SKB_CB(skb)->dccpd_ack_seq);
198 if (len == 4) { /* no elapsed time included */
199 dccp_pr_debug_cat("\n");
203 if (len == 6) { /* 2-byte elapsed time */
204 __be16 opt_val2 = get_unaligned((__be16 *)value);
205 elapsed_time = ntohs(opt_val2);
206 } else { /* 4-byte elapsed time */
207 opt_val = get_unaligned((__be32 *)value);
208 elapsed_time = ntohl(opt_val);
211 dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
213 /* Give precedence to the biggest ELAPSED_TIME */
214 if (elapsed_time > opt_recv->dccpor_elapsed_time)
215 opt_recv->dccpor_elapsed_time = elapsed_time;
217 case DCCPO_ELAPSED_TIME:
218 if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
222 __be16 opt_val2 = get_unaligned((__be16 *)value);
223 elapsed_time = ntohs(opt_val2);
224 } else if (len == 4) {
225 opt_val = get_unaligned((__be32 *)value);
226 elapsed_time = ntohl(opt_val);
228 goto out_invalid_option;
231 if (elapsed_time > opt_recv->dccpor_elapsed_time)
232 opt_recv->dccpor_elapsed_time = elapsed_time;
234 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
235 dccp_role(sk), elapsed_time);
238 const u16 idx = value - options;
240 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
243 goto out_invalid_option;
247 const u16 idx = value - options;
249 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
252 goto out_invalid_option;
256 DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
257 "implemented, ignoring", sk, opt, len);
261 if (opt != DCCPO_MANDATORY)
265 /* mandatory was the last byte in option list -> reset connection */
267 goto out_invalid_option;
272 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
273 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
274 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
278 EXPORT_SYMBOL_GPL(dccp_parse_options);
280 static void dccp_encode_value_var(const u32 value, unsigned char *to,
281 const unsigned int len)
284 *to++ = (value & 0xFF000000) >> 24;
286 *to++ = (value & 0xFF0000) >> 16;
288 *to++ = (value & 0xFF00) >> 8;
290 *to++ = (value & 0xFF);
293 static inline int dccp_ndp_len(const int ndp)
295 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
298 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
299 const unsigned char option,
300 const void *value, const unsigned char len)
304 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
307 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
309 to = skb_push(skb, len + 2);
313 memcpy(to, value, len);
317 EXPORT_SYMBOL_GPL(dccp_insert_option);
319 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
321 struct dccp_sock *dp = dccp_sk(sk);
322 int ndp = dp->dccps_ndp_count;
324 if (dccp_non_data_packet(skb))
325 ++dp->dccps_ndp_count;
327 dp->dccps_ndp_count = 0;
331 const int ndp_len = dccp_ndp_len(ndp);
332 const int len = ndp_len + 2;
334 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
337 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
339 ptr = skb_push(skb, len);
340 *ptr++ = DCCPO_NDP_COUNT;
342 dccp_encode_value_var(ndp, ptr, ndp_len);
348 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
350 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
353 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
356 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
357 const int len = 2 + elapsed_time_len;
360 if (elapsed_time_len == 0)
363 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
366 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
368 to = skb_push(skb, len);
369 *to++ = DCCPO_ELAPSED_TIME;
372 if (elapsed_time_len == 2) {
373 const __be16 var16 = htons((u16)elapsed_time);
374 memcpy(to, &var16, 2);
376 const __be32 var32 = htonl(elapsed_time);
377 memcpy(to, &var32, 4);
383 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
385 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
387 __be32 now = htonl(dccp_timestamp());
388 /* yes this will overflow but that is the point as we want a
389 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
391 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
394 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
396 static int dccp_insert_option_timestamp_echo(struct sock *sk,
399 struct dccp_sock *dp = dccp_sk(sk);
401 int len, elapsed_time_len;
403 const suseconds_t delta = ktime_us_delta(ktime_get_real(),
404 dp->dccps_timestamp_time);
405 u32 elapsed_time = delta / 10;
406 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
407 len = 6 + elapsed_time_len;
409 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
412 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
414 to = skb_push(skb, len);
415 *to++ = DCCPO_TIMESTAMP_ECHO;
418 tstamp_echo = htonl(dp->dccps_timestamp_echo);
419 memcpy(to, &tstamp_echo, 4);
422 if (elapsed_time_len == 2) {
423 const __be16 var16 = htons((u16)elapsed_time);
424 memcpy(to, &var16, 2);
425 } else if (elapsed_time_len == 4) {
426 const __be32 var32 = htonl(elapsed_time);
427 memcpy(to, &var32, 4);
430 dp->dccps_timestamp_echo = 0;
431 dp->dccps_timestamp_time = ktime_set(0, 0);
435 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
440 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
441 DCCP_WARN("packet too small for feature %d option!\n", feat);
445 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
447 to = skb_push(skb, len + 3);
453 memcpy(to, val, len);
455 dccp_pr_debug("%s(%s (%d), ...), length %d\n",
456 dccp_feat_typename(type),
457 dccp_feat_name(feat), feat, len);
461 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
463 struct dccp_sock *dp = dccp_sk(sk);
464 struct dccp_minisock *dmsk = dccp_msk(sk);
465 struct dccp_opt_pend *opt, *next;
468 /* confirm any options [NN opts] */
469 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
470 dccp_insert_feat_opt(skb, opt->dccpop_type,
471 opt->dccpop_feat, opt->dccpop_val,
473 /* fear empty confirms */
475 kfree(opt->dccpop_val);
478 INIT_LIST_HEAD(&dmsk->dccpms_conf);
480 /* see which features we need to send */
481 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
482 /* see if we need to send any confirm */
483 if (opt->dccpop_sc) {
484 dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
486 opt->dccpop_sc->dccpoc_val,
487 opt->dccpop_sc->dccpoc_len);
489 BUG_ON(!opt->dccpop_sc->dccpoc_val);
490 kfree(opt->dccpop_sc->dccpoc_val);
491 kfree(opt->dccpop_sc);
492 opt->dccpop_sc = NULL;
495 /* any option not confirmed, re-send it */
496 if (!opt->dccpop_conf) {
497 dccp_insert_feat_opt(skb, opt->dccpop_type,
498 opt->dccpop_feat, opt->dccpop_val,
505 * If this is the master listening sock, we don't set a timer on it. It
506 * should be fine because if the dude doesn't receive our RESPONSE
507 * [which will contain the CHANGE] he will send another REQUEST which
508 * will "retrnasmit" the change.
510 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
511 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
513 /* XXX don't reset the timer on re-transmissions. I.e. reset it
514 * only when sending new stuff i guess. Currently the timer
515 * never backs off because on re-transmission it just resets it!
517 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
518 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
524 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
526 struct dccp_sock *dp = dccp_sk(sk);
527 struct dccp_minisock *dmsk = dccp_msk(sk);
529 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
531 if (dmsk->dccpms_send_ndp_count &&
532 dccp_insert_option_ndp(sk, skb))
535 if (!dccp_packet_without_ack(skb)) {
536 if (dmsk->dccpms_send_ack_vector &&
537 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
538 dccp_insert_option_ackvec(sk, skb))
541 if (dp->dccps_timestamp_echo != 0 &&
542 dccp_insert_option_timestamp_echo(sk, skb))
546 if (dp->dccps_hc_rx_insert_options) {
547 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
549 dp->dccps_hc_rx_insert_options = 0;
552 /* Feature negotiation */
553 /* Data packets can't do feat negotiation */
554 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
555 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
556 dccp_insert_options_feat(sk, skb))
560 * Obtain RTT sample from Request/Response exchange.
561 * This is currently used in CCID 3 initialisation.
563 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
564 dccp_insert_option_timestamp(sk, skb))
567 /* XXX: insert other options when appropriate */
569 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
570 /* The length of all options has to be a multiple of 4 */
571 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
574 padding = 4 - padding;
575 memset(skb_push(skb, padding), 0, padding);
576 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;