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 : elapsed_time <= 0xFFFF ? 2 : 4;
299 void dccp_insert_option_elapsed_time(struct sock *sk,
303 #ifdef CONFIG_IP_DCCP_DEBUG
304 struct dccp_sock *dp = dccp_sk(sk);
305 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
306 "CLIENT TX opt: " : "server TX opt: ";
308 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
309 const int len = 2 + elapsed_time_len;
312 /* If elapsed_time == 0... */
313 if (elapsed_time_len == 2)
316 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
317 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
318 "insert elapsed time!\n");
322 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
324 to = skb_push(skb, len);
325 *to++ = DCCPO_ELAPSED_TIME;
328 dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
330 dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
331 debug_prefix, elapsed_time,
333 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
336 EXPORT_SYMBOL(dccp_insert_option_elapsed_time);
338 static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
340 struct dccp_sock *dp = dccp_sk(sk);
341 #ifdef CONFIG_IP_DCCP_DEBUG
342 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
343 "CLIENT TX opt: " : "server TX opt: ";
345 struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
346 int len = ap->dccpap_buf_vector_len + 2;
347 const u32 elapsed_time = jiffies_to_usecs(jiffies - ap->dccpap_time) / 10;
348 unsigned char *to, *from;
350 if (elapsed_time != 0)
351 dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
353 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
354 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
355 "insert ACK Vector!\n");
360 * XXX: now we have just one ack vector sent record, so
361 * we have to wait for it to be cleared.
363 * Of course this is not acceptable, but this is just for
366 if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
369 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
371 to = skb_push(skb, len);
372 *to++ = DCCPO_ACK_VECTOR_0;
375 len = ap->dccpap_buf_vector_len;
376 from = ap->dccpap_buf + ap->dccpap_buf_head;
378 /* Check if buf_head wraps */
379 if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
380 const unsigned int tailsize = (ap->dccpap_buf_len -
381 ap->dccpap_buf_head);
383 memcpy(to, from, tailsize);
386 from = ap->dccpap_buf;
389 memcpy(to, from, len);
391 * From draft-ietf-dccp-spec-11.txt:
393 * For each acknowledgement it sends, the HC-Receiver will add an
394 * acknowledgement record. ack_seqno will equal the HC-Receiver
395 * sequence number it used for the ack packet; ack_ptr will equal
396 * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
399 * This implemention uses just one ack record for now.
401 ap->dccpap_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
402 ap->dccpap_ack_ptr = ap->dccpap_buf_head;
403 ap->dccpap_ack_ackno = ap->dccpap_buf_ackno;
404 ap->dccpap_ack_nonce = ap->dccpap_buf_nonce;
405 ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
407 dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
409 debug_prefix, ap->dccpap_ack_vector_len,
410 (unsigned long long) ap->dccpap_ack_seqno,
411 (unsigned long long) ap->dccpap_ack_ackno);
414 static inline void dccp_insert_option_timestamp(struct sock *sk,
417 const u32 now = htonl(tcp_time_stamp);
418 dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
421 static void dccp_insert_option_timestamp_echo(struct sock *sk,
424 struct dccp_sock *dp = dccp_sk(sk);
425 #ifdef CONFIG_IP_DCCP_DEBUG
426 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
427 "CLIENT TX opt: " : "server TX opt: ";
430 const u32 elapsed_time = jiffies_to_usecs(jiffies -
431 dp->dccps_timestamp_time) / 10;
432 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
433 const int len = 6 + elapsed_time_len;
436 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
437 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
438 "timestamp echo!\n");
442 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
444 to = skb_push(skb, len);
445 *to++ = DCCPO_TIMESTAMP_ECHO;
448 tstamp_echo = htonl(dp->dccps_timestamp_echo);
449 memcpy(to, &tstamp_echo, 4);
451 dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
453 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
454 debug_prefix, dp->dccps_timestamp_echo,
456 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
458 dp->dccps_timestamp_echo = 0;
459 dp->dccps_timestamp_time = 0;
462 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
464 struct dccp_sock *dp = dccp_sk(sk);
466 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
468 if (dp->dccps_options.dccpo_send_ndp_count)
469 dccp_insert_option_ndp(sk, skb);
471 if (!dccp_packet_without_ack(skb)) {
472 if (dp->dccps_options.dccpo_send_ack_vector &&
473 (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
475 dccp_insert_option_ack_vector(sk, skb);
477 dccp_insert_option_timestamp(sk, skb);
478 if (dp->dccps_timestamp_echo != 0)
479 dccp_insert_option_timestamp_echo(sk, skb);
482 ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
483 ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
485 /* XXX: insert other options when appropriate */
487 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
488 /* The length of all options has to be a multiple of 4 */
489 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
492 padding = 4 - padding;
493 memset(skb_push(skb, padding), 0, padding);
494 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
499 struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
500 const unsigned int __nocast priority)
502 struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
505 #ifdef CONFIG_IP_DCCP_DEBUG
506 memset(ap->dccpap_buf, 0xFF, len);
508 ap->dccpap_buf_len = len;
509 ap->dccpap_buf_head =
510 ap->dccpap_buf_tail =
511 ap->dccpap_buf_len - 1;
512 ap->dccpap_buf_ackno =
513 ap->dccpap_ack_ackno =
514 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
515 ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
516 ap->dccpap_ack_ptr = 0;
518 ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
524 void dccp_ackpkts_free(struct dccp_ackpkts *ap)
527 #ifdef CONFIG_IP_DCCP_DEBUG
528 memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
534 static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
535 const unsigned int index)
537 return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
540 static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
541 const unsigned int index)
543 return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
547 * If several packets are missing, the HC-Receiver may prefer to enter multiple
548 * bytes with run length 0, rather than a single byte with a larger run length;
549 * this simplifies table updates if one of the missing packets arrives.
551 static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
552 const unsigned int packets,
553 const unsigned char state)
556 signed long new_head;
558 if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
562 new_head = ap->dccpap_buf_head - packets;
566 memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
570 new_head += ap->dccpap_buf_len;
573 ap->dccpap_buf_head = new_head;
576 memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
577 DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
579 ap->dccpap_buf[ap->dccpap_buf_head] = state;
580 ap->dccpap_buf_vector_len += packets;
585 * Implements the draft-ietf-dccp-spec-11.txt Appendix A
587 int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state)
590 * Check at the right places if the buffer is full, if it is, tell the
591 * caller to start dropping packets till the HC-Sender acks our ACK
592 * vectors, when we will free up space in dccpap_buf.
594 * We may well decide to do buffer compression, etc, but for now lets
599 * Of course, the circular buffer may overflow, either when the
600 * HC-Sender is sending data at a very high rate, when the
601 * HC-Receiver's acknowledgements are not reaching the HC-Sender,
602 * or when the HC-Sender is forgetting to acknowledge those acks
603 * (so the HC-Receiver is unable to clean up old state). In this
604 * case, the HC-Receiver should either compress the buffer (by
605 * increasing run lengths when possible), transfer its state to
606 * a larger buffer, or, as a last resort, drop all received
607 * packets, without processing them whatsoever, until its buffer
611 /* See if this is the first ackno being inserted */
612 if (ap->dccpap_buf_vector_len == 0) {
613 ap->dccpap_buf[ap->dccpap_buf_head] = state;
614 ap->dccpap_buf_vector_len = 1;
615 } else if (after48(ackno, ap->dccpap_buf_ackno)) {
616 const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
620 * Look if the state of this packet is the same as the
621 * previous ackno and if so if we can bump the head len.
624 dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
625 (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
626 DCCP_ACKPKTS_LEN_MASK))
627 ap->dccpap_buf[ap->dccpap_buf_head]++;
628 else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
634 * When a packet with Sequence Number S arrives, and
635 * S <= buf_ackno, the HC-Receiver will scan the table
636 * for the byte corresponding to S. (Indexing structures
637 * could reduce the complexity of this scan.)
639 u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
640 unsigned int index = ap->dccpap_buf_head;
643 const u8 len = dccp_ackpkts_len(ap, index);
644 const u8 state = dccp_ackpkts_state(ap, index);
646 * valid packets not yet in dccpap_buf have a reserved
647 * entry, with a len equal to 0.
649 if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
650 len == 0 && delta == 0) { /* Found our
652 dccp_pr_debug("Found %llu reserved seat!\n",
653 (unsigned long long) ackno);
654 ap->dccpap_buf[index] = state;
657 /* len == 0 means one packet */
662 if (++index == ap->dccpap_buf_len)
667 ap->dccpap_buf_ackno = ackno;
668 ap->dccpap_time = jiffies;
671 dccp_ackpkts_print(ap);
675 /* Duplicate packet */
676 dccp_pr_debug("Received a dup or already considered lost "
677 "packet: %llu\n", (unsigned long long) ackno);
681 #ifdef CONFIG_IP_DCCP_DEBUG
682 void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
688 printk("ACK vector len=%d, ackno=%llu |", len,
689 (unsigned long long) ackno);
692 const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
693 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
695 printk("%d,%d|", state, rl);
702 void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
704 dccp_ackvector_print(ap->dccpap_buf_ackno,
705 ap->dccpap_buf + ap->dccpap_buf_head,
706 ap->dccpap_buf_vector_len);
710 static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
713 * As we're keeping track of the ack vector size
714 * (dccpap_buf_vector_len) and the sent ack vector size
715 * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
716 * keep this code here as in the future we'll implement a vector of
717 * ack records, as suggested in draft-ietf-dccp-spec-11.txt
721 ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
722 if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
723 ap->dccpap_buf_tail -= ap->dccpap_buf_len;
725 ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
728 void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
731 /* Check if we actually sent an ACK vector */
732 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
735 if (ackno == ap->dccpap_ack_seqno) {
736 #ifdef CONFIG_IP_DCCP_DEBUG
737 struct dccp_sock *dp = dccp_sk(sk);
738 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
739 "CLIENT rx ack: " : "server rx ack: ";
741 dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
742 "ack_ackno=%llu, ACKED!\n",
744 (unsigned long long) ap->dccpap_ack_seqno,
745 (unsigned long long) ap->dccpap_ack_ackno);
746 dccp_ackpkts_trow_away_ack_record(ap);
747 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
751 static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
752 struct sock *sk, u64 ackno,
753 const unsigned char len,
754 const unsigned char *vector)
758 /* Check if we actually sent an ACK vector */
759 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
762 * We're in the receiver half connection, so if the received an ACK
763 * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
766 * Extra explanation with example:
768 * if we received an ACK vector with ackno 50, it can only be acking
769 * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
771 /* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
772 if (before48(ackno, ap->dccpap_ack_seqno)) {
773 /* dccp_pr_debug_cat("yes\n"); */
776 /* dccp_pr_debug_cat("no\n"); */
780 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
783 dccp_set_seqno(&ackno_end_rl, ackno - rl);
786 * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
787 * ap->dccpap_ack_seqno, ackno);
789 if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
790 const u8 state = (*vector &
791 DCCP_ACKPKTS_STATE_MASK) >> 6;
792 /* dccp_pr_debug_cat("yes\n"); */
794 if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
795 #ifdef CONFIG_IP_DCCP_DEBUG
796 struct dccp_sock *dp = dccp_sk(sk);
797 const char *debug_prefix =
798 dp->dccps_role == DCCP_ROLE_CLIENT ?
799 "CLIENT rx ack: " : "server rx ack: ";
801 dccp_pr_debug("%sACK vector 0, len=%d, "
802 "ack_seqno=%llu, ack_ackno=%llu, "
806 ap->dccpap_ack_seqno,
808 ap->dccpap_ack_ackno);
809 dccp_ackpkts_trow_away_ack_record(ap);
812 * If dccpap_ack_seqno was not received, no problem
813 * we'll send another ACK vector.
815 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
818 /* dccp_pr_debug_cat("no\n"); */
820 dccp_set_seqno(&ackno, ackno_end_rl - 1);