4 * An implementation of the DCCP protocol
5 * Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
6 * Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 #include <linux/config.h>
14 #include <linux/dccp.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/skbuff.h>
23 static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
26 const unsigned char len,
27 const unsigned char *vector);
29 /* stores the default values for new connection. may be changed with sysctl */
30 static const struct dccp_options dccpo_default_values = {
31 .dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
32 .dccpo_ccid = DCCPF_INITIAL_CCID,
33 .dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
34 .dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
37 void dccp_options_init(struct dccp_options *dccpo)
39 memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
42 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
58 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
60 struct dccp_sock *dp = dccp_sk(sk);
61 #ifdef CONFIG_IP_DCCP_DEBUG
62 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
63 "CLIENT rx opt: " : "server rx opt: ";
65 const struct dccp_hdr *dh = dccp_hdr(skb);
66 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
67 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
68 unsigned char *opt_ptr = options;
69 const unsigned char *opt_end = (unsigned char *)dh +
71 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
72 unsigned char opt, len;
75 memset(opt_recv, 0, sizeof(*opt_recv));
77 while (opt_ptr != opt_end) {
82 /* Check if this isn't a single byte option */
83 if (opt > DCCPO_MAX_RESERVED) {
84 if (opt_ptr == opt_end)
85 goto out_invalid_option;
89 goto out_invalid_option;
91 * Remove the type and len fields, leaving
98 if (opt_ptr > opt_end)
99 goto out_invalid_option;
105 case DCCPO_NDP_COUNT:
107 goto out_invalid_option;
109 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
110 dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
111 opt_recv->dccpor_ndp);
113 case DCCPO_ACK_VECTOR_0:
114 if (len > DCCP_MAX_ACK_VECTOR_LEN)
115 goto out_invalid_option;
117 if (pkt_type == DCCP_PKT_DATA)
120 opt_recv->dccpor_ack_vector_len = len;
121 opt_recv->dccpor_ack_vector_idx = value - options;
123 dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n",
126 DCCP_SKB_CB(skb)->dccpd_ack_seq);
127 dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq,
129 dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts,
131 DCCP_SKB_CB(skb)->dccpd_ack_seq,
134 case DCCPO_TIMESTAMP:
136 goto out_invalid_option;
138 opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
140 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
141 dp->dccps_timestamp_time = jiffies;
143 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
144 debug_prefix, opt_recv->dccpor_timestamp,
146 DCCP_SKB_CB(skb)->dccpd_ack_seq);
148 case DCCPO_TIMESTAMP_ECHO:
149 if (len < 4 || len > 8)
150 goto out_invalid_option;
152 opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
154 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, "
157 opt_recv->dccpor_timestamp_echo,
160 DCCP_SKB_CB(skb)->dccpd_ack_seq,
162 opt_recv->dccpor_timestamp_echo));
164 opt_recv->dccpor_elapsed_time =
165 dccp_decode_value_var(value + 4,
167 dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n",
169 opt_recv->dccpor_elapsed_time);
171 case DCCPO_ELAPSED_TIME:
173 goto out_invalid_option;
175 if (pkt_type == DCCP_PKT_DATA)
177 opt_recv->dccpor_elapsed_time =
178 dccp_decode_value_var(value, len);
179 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
180 opt_recv->dccpor_elapsed_time);
183 * From draft-ietf-dccp-spec-11.txt:
185 * Option numbers 128 through 191 are for
186 * options sent from the HC-Sender to the
187 * HC-Receiver; option numbers 192 through 255
188 * are for options sent from the HC-Receiver to
192 const u16 idx = value - options;
194 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
197 goto out_invalid_option;
201 const u16 idx = value - options;
203 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
206 goto out_invalid_option;
210 pr_info("DCCP(%p): option %d(len=%d) not "
211 "implemented, ignoring\n",
220 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
221 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
222 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
226 static void dccp_encode_value_var(const u32 value, unsigned char *to,
227 const unsigned int len)
230 *to++ = (value & 0xFF000000) >> 24;
232 *to++ = (value & 0xFF0000) >> 16;
234 *to++ = (value & 0xFF00) >> 8;
236 *to++ = (value & 0xFF);
239 static inline int dccp_ndp_len(const int ndp)
241 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
244 void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
245 const unsigned char option,
246 const void *value, const unsigned char len)
250 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
251 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
252 "%d option!\n", option);
256 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
258 to = skb_push(skb, len + 2);
262 memcpy(to, value, len);
265 EXPORT_SYMBOL_GPL(dccp_insert_option);
267 static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
269 struct dccp_sock *dp = dccp_sk(sk);
270 int ndp = dp->dccps_ndp_count;
272 if (dccp_non_data_packet(skb))
273 ++dp->dccps_ndp_count;
275 dp->dccps_ndp_count = 0;
279 const int ndp_len = dccp_ndp_len(ndp);
280 const int len = ndp_len + 2;
282 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
285 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
287 ptr = skb_push(skb, len);
288 *ptr++ = DCCPO_NDP_COUNT;
290 dccp_encode_value_var(ndp, ptr, ndp_len);
294 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
296 return elapsed_time == 0 ? 0 :
297 elapsed_time <= 0xFF ? 1 :
298 elapsed_time <= 0xFFFF ? 2 :
299 elapsed_time <= 0xFFFFFF ? 3 : 4;
302 void dccp_insert_option_elapsed_time(struct sock *sk,
306 #ifdef CONFIG_IP_DCCP_DEBUG
307 struct dccp_sock *dp = dccp_sk(sk);
308 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
309 "CLIENT TX opt: " : "server TX opt: ";
311 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
312 const int len = 2 + elapsed_time_len;
315 /* If elapsed_time == 0... */
316 if (elapsed_time_len == 2)
319 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
320 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
321 "insert elapsed time!\n");
325 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
327 to = skb_push(skb, len);
328 *to++ = DCCPO_ELAPSED_TIME;
331 dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
333 dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
334 debug_prefix, elapsed_time,
336 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
339 EXPORT_SYMBOL(dccp_insert_option_elapsed_time);
341 static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
343 struct dccp_sock *dp = dccp_sk(sk);
344 #ifdef CONFIG_IP_DCCP_DEBUG
345 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
346 "CLIENT TX opt: " : "server TX opt: ";
348 struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
349 int len = ap->dccpap_buf_vector_len + 2;
350 const u32 elapsed_time = jiffies_to_usecs(jiffies - ap->dccpap_time) / 10;
351 unsigned char *to, *from;
353 if (elapsed_time != 0)
354 dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
356 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
357 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
358 "insert ACK Vector!\n");
363 * XXX: now we have just one ack vector sent record, so
364 * we have to wait for it to be cleared.
366 * Of course this is not acceptable, but this is just for
369 if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
372 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
374 to = skb_push(skb, len);
375 *to++ = DCCPO_ACK_VECTOR_0;
378 len = ap->dccpap_buf_vector_len;
379 from = ap->dccpap_buf + ap->dccpap_buf_head;
381 /* Check if buf_head wraps */
382 if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
383 const unsigned int tailsize = (ap->dccpap_buf_len -
384 ap->dccpap_buf_head);
386 memcpy(to, from, tailsize);
389 from = ap->dccpap_buf;
392 memcpy(to, from, len);
394 * From draft-ietf-dccp-spec-11.txt:
396 * For each acknowledgement it sends, the HC-Receiver will add an
397 * acknowledgement record. ack_seqno will equal the HC-Receiver
398 * sequence number it used for the ack packet; ack_ptr will equal
399 * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
402 * This implemention uses just one ack record for now.
404 ap->dccpap_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
405 ap->dccpap_ack_ptr = ap->dccpap_buf_head;
406 ap->dccpap_ack_ackno = ap->dccpap_buf_ackno;
407 ap->dccpap_ack_nonce = ap->dccpap_buf_nonce;
408 ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
410 dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
412 debug_prefix, ap->dccpap_ack_vector_len,
413 (unsigned long long) ap->dccpap_ack_seqno,
414 (unsigned long long) ap->dccpap_ack_ackno);
417 static inline void dccp_insert_option_timestamp(struct sock *sk,
420 const u32 now = htonl(tcp_time_stamp);
421 dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
424 static void dccp_insert_option_timestamp_echo(struct sock *sk,
427 struct dccp_sock *dp = dccp_sk(sk);
428 #ifdef CONFIG_IP_DCCP_DEBUG
429 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
430 "CLIENT TX opt: " : "server TX opt: ";
433 const u32 elapsed_time = jiffies_to_usecs(jiffies -
434 dp->dccps_timestamp_time) / 10;
435 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
436 const int len = 6 + elapsed_time_len;
439 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
440 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
441 "timestamp echo!\n");
445 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
447 to = skb_push(skb, len);
448 *to++ = DCCPO_TIMESTAMP_ECHO;
451 tstamp_echo = htonl(dp->dccps_timestamp_echo);
452 memcpy(to, &tstamp_echo, 4);
454 dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
456 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
457 debug_prefix, dp->dccps_timestamp_echo,
459 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
461 dp->dccps_timestamp_echo = 0;
462 dp->dccps_timestamp_time = 0;
465 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
467 struct dccp_sock *dp = dccp_sk(sk);
469 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
471 if (dp->dccps_options.dccpo_send_ndp_count)
472 dccp_insert_option_ndp(sk, skb);
474 if (!dccp_packet_without_ack(skb)) {
475 if (dp->dccps_options.dccpo_send_ack_vector &&
476 (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
478 dccp_insert_option_ack_vector(sk, skb);
480 dccp_insert_option_timestamp(sk, skb);
481 if (dp->dccps_timestamp_echo != 0)
482 dccp_insert_option_timestamp_echo(sk, skb);
485 ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
486 ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
488 /* XXX: insert other options when appropriate */
490 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
491 /* The length of all options has to be a multiple of 4 */
492 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
495 padding = 4 - padding;
496 memset(skb_push(skb, padding), 0, padding);
497 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
502 struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
503 const unsigned int __nocast priority)
505 struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
508 #ifdef CONFIG_IP_DCCP_DEBUG
509 memset(ap->dccpap_buf, 0xFF, len);
511 ap->dccpap_buf_len = len;
512 ap->dccpap_buf_head =
513 ap->dccpap_buf_tail =
514 ap->dccpap_buf_len - 1;
515 ap->dccpap_buf_ackno =
516 ap->dccpap_ack_ackno =
517 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
518 ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
519 ap->dccpap_ack_ptr = 0;
521 ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
527 void dccp_ackpkts_free(struct dccp_ackpkts *ap)
530 #ifdef CONFIG_IP_DCCP_DEBUG
531 memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
537 static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
538 const unsigned int index)
540 return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
543 static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
544 const unsigned int index)
546 return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
550 * If several packets are missing, the HC-Receiver may prefer to enter multiple
551 * bytes with run length 0, rather than a single byte with a larger run length;
552 * this simplifies table updates if one of the missing packets arrives.
554 static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
555 const unsigned int packets,
556 const unsigned char state)
559 signed long new_head;
561 if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
565 new_head = ap->dccpap_buf_head - packets;
569 memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
573 new_head += ap->dccpap_buf_len;
576 ap->dccpap_buf_head = new_head;
579 memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
580 DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
582 ap->dccpap_buf[ap->dccpap_buf_head] = state;
583 ap->dccpap_buf_vector_len += packets;
588 * Implements the draft-ietf-dccp-spec-11.txt Appendix A
590 int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state)
593 * Check at the right places if the buffer is full, if it is, tell the
594 * caller to start dropping packets till the HC-Sender acks our ACK
595 * vectors, when we will free up space in dccpap_buf.
597 * We may well decide to do buffer compression, etc, but for now lets
602 * Of course, the circular buffer may overflow, either when the
603 * HC-Sender is sending data at a very high rate, when the
604 * HC-Receiver's acknowledgements are not reaching the HC-Sender,
605 * or when the HC-Sender is forgetting to acknowledge those acks
606 * (so the HC-Receiver is unable to clean up old state). In this
607 * case, the HC-Receiver should either compress the buffer (by
608 * increasing run lengths when possible), transfer its state to
609 * a larger buffer, or, as a last resort, drop all received
610 * packets, without processing them whatsoever, until its buffer
614 /* See if this is the first ackno being inserted */
615 if (ap->dccpap_buf_vector_len == 0) {
616 ap->dccpap_buf[ap->dccpap_buf_head] = state;
617 ap->dccpap_buf_vector_len = 1;
618 } else if (after48(ackno, ap->dccpap_buf_ackno)) {
619 const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
623 * Look if the state of this packet is the same as the
624 * previous ackno and if so if we can bump the head len.
627 dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
628 (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
629 DCCP_ACKPKTS_LEN_MASK))
630 ap->dccpap_buf[ap->dccpap_buf_head]++;
631 else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
637 * When a packet with Sequence Number S arrives, and
638 * S <= buf_ackno, the HC-Receiver will scan the table
639 * for the byte corresponding to S. (Indexing structures
640 * could reduce the complexity of this scan.)
642 u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
643 unsigned int index = ap->dccpap_buf_head;
646 const u8 len = dccp_ackpkts_len(ap, index);
647 const u8 state = dccp_ackpkts_state(ap, index);
649 * valid packets not yet in dccpap_buf have a reserved
650 * entry, with a len equal to 0.
652 if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
653 len == 0 && delta == 0) { /* Found our
655 dccp_pr_debug("Found %llu reserved seat!\n",
656 (unsigned long long) ackno);
657 ap->dccpap_buf[index] = state;
660 /* len == 0 means one packet */
665 if (++index == ap->dccpap_buf_len)
670 ap->dccpap_buf_ackno = ackno;
671 ap->dccpap_time = jiffies;
674 dccp_ackpkts_print(ap);
678 /* Duplicate packet */
679 dccp_pr_debug("Received a dup or already considered lost "
680 "packet: %llu\n", (unsigned long long) ackno);
684 #ifdef CONFIG_IP_DCCP_DEBUG
685 void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
691 printk("ACK vector len=%d, ackno=%llu |", len,
692 (unsigned long long) ackno);
695 const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
696 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
698 printk("%d,%d|", state, rl);
705 void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
707 dccp_ackvector_print(ap->dccpap_buf_ackno,
708 ap->dccpap_buf + ap->dccpap_buf_head,
709 ap->dccpap_buf_vector_len);
713 static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
716 * As we're keeping track of the ack vector size
717 * (dccpap_buf_vector_len) and the sent ack vector size
718 * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
719 * keep this code here as in the future we'll implement a vector of
720 * ack records, as suggested in draft-ietf-dccp-spec-11.txt
724 ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
725 if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
726 ap->dccpap_buf_tail -= ap->dccpap_buf_len;
728 ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
731 void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
734 /* Check if we actually sent an ACK vector */
735 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
738 if (ackno == ap->dccpap_ack_seqno) {
739 #ifdef CONFIG_IP_DCCP_DEBUG
740 struct dccp_sock *dp = dccp_sk(sk);
741 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
742 "CLIENT rx ack: " : "server rx ack: ";
744 dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
745 "ack_ackno=%llu, ACKED!\n",
747 (unsigned long long) ap->dccpap_ack_seqno,
748 (unsigned long long) ap->dccpap_ack_ackno);
749 dccp_ackpkts_trow_away_ack_record(ap);
750 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
754 static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
755 struct sock *sk, u64 ackno,
756 const unsigned char len,
757 const unsigned char *vector)
761 /* Check if we actually sent an ACK vector */
762 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
765 * We're in the receiver half connection, so if the received an ACK
766 * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
769 * Extra explanation with example:
771 * if we received an ACK vector with ackno 50, it can only be acking
772 * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
774 /* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
775 if (before48(ackno, ap->dccpap_ack_seqno)) {
776 /* dccp_pr_debug_cat("yes\n"); */
779 /* dccp_pr_debug_cat("no\n"); */
783 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
786 dccp_set_seqno(&ackno_end_rl, ackno - rl);
789 * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
790 * ap->dccpap_ack_seqno, ackno);
792 if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
793 const u8 state = (*vector &
794 DCCP_ACKPKTS_STATE_MASK) >> 6;
795 /* dccp_pr_debug_cat("yes\n"); */
797 if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
798 #ifdef CONFIG_IP_DCCP_DEBUG
799 struct dccp_sock *dp = dccp_sk(sk);
800 const char *debug_prefix =
801 dp->dccps_role == DCCP_ROLE_CLIENT ?
802 "CLIENT rx ack: " : "server rx ack: ";
804 dccp_pr_debug("%sACK vector 0, len=%d, "
805 "ack_seqno=%llu, ack_ackno=%llu, "
809 ap->dccpap_ack_seqno,
811 ap->dccpap_ack_ackno);
812 dccp_ackpkts_trow_away_ack_record(ap);
815 * If dccpap_ack_seqno was not received, no problem
816 * we'll send another ACK vector.
818 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
821 /* dccp_pr_debug_cat("no\n"); */
823 dccp_set_seqno(&ackno, ackno_end_rl - 1);