2 * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
4 * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
6 * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 * This implementation should follow RFC 4341
26 #include <linux/slab.h>
31 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
32 static int ccid2_debug
;
33 #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
35 #define ccid2_pr_debug(format, a...)
38 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock
*hc
)
40 struct ccid2_seq
*seqp
;
43 /* check if we have space to preserve the pointer to the buffer */
44 if (hc
->tx_seqbufc
>= (sizeof(hc
->tx_seqbuf
) /
45 sizeof(struct ccid2_seq
*)))
48 /* allocate buffer and initialize linked list */
49 seqp
= kmalloc(CCID2_SEQBUF_LEN
* sizeof(struct ccid2_seq
), gfp_any());
53 for (i
= 0; i
< (CCID2_SEQBUF_LEN
- 1); i
++) {
54 seqp
[i
].ccid2s_next
= &seqp
[i
+ 1];
55 seqp
[i
+ 1].ccid2s_prev
= &seqp
[i
];
57 seqp
[CCID2_SEQBUF_LEN
- 1].ccid2s_next
= seqp
;
58 seqp
->ccid2s_prev
= &seqp
[CCID2_SEQBUF_LEN
- 1];
60 /* This is the first allocation. Initiate the head and tail. */
61 if (hc
->tx_seqbufc
== 0)
62 hc
->tx_seqh
= hc
->tx_seqt
= seqp
;
64 /* link the existing list with the one we just created */
65 hc
->tx_seqh
->ccid2s_next
= seqp
;
66 seqp
->ccid2s_prev
= hc
->tx_seqh
;
68 hc
->tx_seqt
->ccid2s_prev
= &seqp
[CCID2_SEQBUF_LEN
- 1];
69 seqp
[CCID2_SEQBUF_LEN
- 1].ccid2s_next
= hc
->tx_seqt
;
72 /* store the original pointer to the buffer so we can free it */
73 hc
->tx_seqbuf
[hc
->tx_seqbufc
] = seqp
;
79 static int ccid2_hc_tx_send_packet(struct sock
*sk
, struct sk_buff
*skb
)
81 if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk
)))
82 return CCID_PACKET_WILL_DEQUEUE_LATER
;
83 return CCID_PACKET_SEND_AT_ONCE
;
86 static void ccid2_change_l_ack_ratio(struct sock
*sk
, u32 val
)
88 struct dccp_sock
*dp
= dccp_sk(sk
);
89 u32 max_ratio
= DIV_ROUND_UP(ccid2_hc_tx_sk(sk
)->tx_cwnd
, 2);
92 * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
93 * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
94 * acceptable since this causes starvation/deadlock whenever cwnd < 2.
95 * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
97 if (val
== 0 || val
> max_ratio
) {
98 DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val
, max_ratio
);
101 if (val
> DCCPF_ACK_RATIO_MAX
)
102 val
= DCCPF_ACK_RATIO_MAX
;
104 if (val
== dp
->dccps_l_ack_ratio
)
107 ccid2_pr_debug("changing local ack ratio to %u\n", val
);
108 dp
->dccps_l_ack_ratio
= val
;
111 static void ccid2_hc_tx_rto_expire(unsigned long data
)
113 struct sock
*sk
= (struct sock
*)data
;
114 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
115 const bool sender_was_blocked
= ccid2_cwnd_network_limited(hc
);
118 if (sock_owned_by_user(sk
)) {
119 sk_reset_timer(sk
, &hc
->tx_rtotimer
, jiffies
+ HZ
/ 5);
123 ccid2_pr_debug("RTO_EXPIRE\n");
127 if (hc
->tx_rto
> DCCP_RTO_MAX
)
128 hc
->tx_rto
= DCCP_RTO_MAX
;
130 /* adjust pipe, cwnd etc */
131 hc
->tx_ssthresh
= hc
->tx_cwnd
/ 2;
132 if (hc
->tx_ssthresh
< 2)
137 /* clear state about stuff we sent */
138 hc
->tx_seqt
= hc
->tx_seqh
;
139 hc
->tx_packets_acked
= 0;
141 /* clear ack ratio state. */
143 hc
->tx_rpdupack
= -1;
144 ccid2_change_l_ack_ratio(sk
, 1);
146 /* if we were blocked before, we may now send cwnd=1 packet */
147 if (sender_was_blocked
)
148 tasklet_schedule(&dccp_sk(sk
)->dccps_xmitlet
);
149 /* restart backed-off timer */
150 sk_reset_timer(sk
, &hc
->tx_rtotimer
, jiffies
+ hc
->tx_rto
);
156 static void ccid2_hc_tx_packet_sent(struct sock
*sk
, unsigned int len
)
158 struct dccp_sock
*dp
= dccp_sk(sk
);
159 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
160 struct ccid2_seq
*next
;
164 hc
->tx_seqh
->ccid2s_seq
= dp
->dccps_gss
;
165 hc
->tx_seqh
->ccid2s_acked
= 0;
166 hc
->tx_seqh
->ccid2s_sent
= ccid2_time_stamp
;
168 next
= hc
->tx_seqh
->ccid2s_next
;
169 /* check if we need to alloc more space */
170 if (next
== hc
->tx_seqt
) {
171 if (ccid2_hc_tx_alloc_seq(hc
)) {
172 DCCP_CRIT("packet history - out of memory!");
173 /* FIXME: find a more graceful way to bail out */
176 next
= hc
->tx_seqh
->ccid2s_next
;
177 BUG_ON(next
== hc
->tx_seqt
);
181 ccid2_pr_debug("cwnd=%d pipe=%d\n", hc
->tx_cwnd
, hc
->tx_pipe
);
184 * FIXME: The code below is broken and the variables have been removed
185 * from the socket struct. The `ackloss' variable was always set to 0,
186 * and with arsent there are several problems:
187 * (i) it doesn't just count the number of Acks, but all sent packets;
188 * (ii) it is expressed in # of packets, not # of windows, so the
189 * comparison below uses the wrong formula: Appendix A of RFC 4341
190 * comes up with the number K = cwnd / (R^2 - R) of consecutive windows
191 * of data with no lost or marked Ack packets. If arsent were the # of
192 * consecutive Acks received without loss, then Ack Ratio needs to be
193 * decreased by 1 when
194 * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2)
195 * where cwnd / R is the number of Acks received per window of data
196 * (cf. RFC 4341, App. A). The problems are that
197 * - arsent counts other packets as well;
198 * - the comparison uses a formula different from RFC 4341;
199 * - computing a cubic/quadratic equation each time is too complicated.
200 * Hence a different algorithm is needed.
203 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
205 /* We had an ack loss in this window... */
206 if (hc
->tx_ackloss
) {
207 if (hc
->tx_arsent
>= hc
->tx_cwnd
) {
212 /* No acks lost up to now... */
213 /* decrease ack ratio if enough packets were sent */
214 if (dp
->dccps_l_ack_ratio
> 1) {
215 /* XXX don't calculate denominator each time */
216 int denom
= dp
->dccps_l_ack_ratio
* dp
->dccps_l_ack_ratio
-
217 dp
->dccps_l_ack_ratio
;
219 denom
= hc
->tx_cwnd
* hc
->tx_cwnd
/ denom
;
221 if (hc
->tx_arsent
>= denom
) {
222 ccid2_change_l_ack_ratio(sk
, dp
->dccps_l_ack_ratio
- 1);
226 /* we can't increase ack ratio further [1] */
227 hc
->tx_arsent
= 0; /* or maybe set it to cwnd*/
232 sk_reset_timer(sk
, &hc
->tx_rtotimer
, jiffies
+ hc
->tx_rto
);
234 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
236 struct ccid2_seq
*seqp
= hc
->tx_seqt
;
238 while (seqp
!= hc
->tx_seqh
) {
239 ccid2_pr_debug("out seq=%llu acked=%d time=%u\n",
240 (unsigned long long)seqp
->ccid2s_seq
,
241 seqp
->ccid2s_acked
, seqp
->ccid2s_sent
);
242 seqp
= seqp
->ccid2s_next
;
245 ccid2_pr_debug("=========\n");
249 /* XXX Lame code duplication!
250 * returns -1 if none was found.
251 * else returns the next offset to use in the function call.
253 static int ccid2_ackvector(struct sock
*sk
, struct sk_buff
*skb
, int offset
,
254 unsigned char **vec
, unsigned char *veclen
)
256 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
257 unsigned char *options
= (unsigned char *)dh
+ dccp_hdr_len(skb
);
258 unsigned char *opt_ptr
;
259 const unsigned char *opt_end
= (unsigned char *)dh
+
260 (dh
->dccph_doff
* 4);
261 unsigned char opt
, len
;
262 unsigned char *value
;
267 if (opt_ptr
>= opt_end
)
270 while (opt_ptr
!= opt_end
) {
275 /* Check if this isn't a single byte option */
276 if (opt
> DCCPO_MAX_RESERVED
) {
277 if (opt_ptr
== opt_end
)
278 goto out_invalid_option
;
282 goto out_invalid_option
;
284 * Remove the type and len fields, leaving
285 * just the value size
291 if (opt_ptr
> opt_end
)
292 goto out_invalid_option
;
296 case DCCPO_ACK_VECTOR_0
:
297 case DCCPO_ACK_VECTOR_1
:
300 return offset
+ (opt_ptr
- options
);
307 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
312 * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
313 * This code is almost identical with TCP's tcp_rtt_estimator(), since
314 * - it has a higher sampling frequency (recommended by RFC 1323),
315 * - the RTO does not collapse into RTT due to RTTVAR going towards zero,
316 * - it is simple (cf. more complex proposals such as Eifel timer or research
317 * which suggests that the gain should be set according to window size),
318 * - in tests it was found to work well with CCID2 [gerrit].
320 static void ccid2_rtt_estimator(struct sock
*sk
, const long mrtt
)
322 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
325 if (hc
->tx_srtt
== 0) {
326 /* First measurement m */
327 hc
->tx_srtt
= m
<< 3;
328 hc
->tx_mdev
= m
<< 1;
330 hc
->tx_mdev_max
= max(hc
->tx_mdev
, tcp_rto_min(sk
));
331 hc
->tx_rttvar
= hc
->tx_mdev_max
;
333 hc
->tx_rtt_seq
= dccp_sk(sk
)->dccps_gss
;
335 /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
336 m
-= (hc
->tx_srtt
>> 3);
339 /* Similarly, update scaled mdev with regard to |m| */
342 m
-= (hc
->tx_mdev
>> 2);
344 * This neutralises RTO increase when RTT < SRTT - mdev
345 * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
346 * in Linux TCP", USENIX 2002, pp. 49-62).
351 m
-= (hc
->tx_mdev
>> 2);
355 if (hc
->tx_mdev
> hc
->tx_mdev_max
) {
356 hc
->tx_mdev_max
= hc
->tx_mdev
;
357 if (hc
->tx_mdev_max
> hc
->tx_rttvar
)
358 hc
->tx_rttvar
= hc
->tx_mdev_max
;
362 * Decay RTTVAR at most once per flight, exploiting that
363 * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2)
364 * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1)
365 * GAR is a useful bound for FlightSize = pipe.
366 * AWL is probably too low here, as it over-estimates pipe.
368 if (after48(dccp_sk(sk
)->dccps_gar
, hc
->tx_rtt_seq
)) {
369 if (hc
->tx_mdev_max
< hc
->tx_rttvar
)
370 hc
->tx_rttvar
-= (hc
->tx_rttvar
-
371 hc
->tx_mdev_max
) >> 2;
372 hc
->tx_rtt_seq
= dccp_sk(sk
)->dccps_gss
;
373 hc
->tx_mdev_max
= tcp_rto_min(sk
);
378 * Set RTO from SRTT and RTTVAR
379 * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms.
380 * This agrees with RFC 4341, 5:
381 * "Because DCCP does not retransmit data, DCCP does not require
382 * TCP's recommended minimum timeout of one second".
384 hc
->tx_rto
= (hc
->tx_srtt
>> 3) + hc
->tx_rttvar
;
386 if (hc
->tx_rto
> DCCP_RTO_MAX
)
387 hc
->tx_rto
= DCCP_RTO_MAX
;
390 static void ccid2_new_ack(struct sock
*sk
, struct ccid2_seq
*seqp
,
391 unsigned int *maxincr
)
393 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
395 if (hc
->tx_cwnd
< hc
->tx_ssthresh
) {
396 if (*maxincr
> 0 && ++hc
->tx_packets_acked
== 2) {
399 hc
->tx_packets_acked
= 0;
401 } else if (++hc
->tx_packets_acked
>= hc
->tx_cwnd
) {
403 hc
->tx_packets_acked
= 0;
406 * FIXME: RTT is sampled several times per acknowledgment (for each
407 * entry in the Ack Vector), instead of once per Ack (as in TCP SACK).
408 * This causes the RTT to be over-estimated, since the older entries
409 * in the Ack Vector have earlier sending times.
410 * The cleanest solution is to not use the ccid2s_sent field at all
411 * and instead use DCCP timestamps: requires changes in other places.
413 ccid2_rtt_estimator(sk
, ccid2_time_stamp
- seqp
->ccid2s_sent
);
416 static void ccid2_congestion_event(struct sock
*sk
, struct ccid2_seq
*seqp
)
418 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
420 if ((s32
)(seqp
->ccid2s_sent
- hc
->tx_last_cong
) < 0) {
421 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
425 hc
->tx_last_cong
= ccid2_time_stamp
;
427 hc
->tx_cwnd
= hc
->tx_cwnd
/ 2 ? : 1U;
428 hc
->tx_ssthresh
= max(hc
->tx_cwnd
, 2U);
430 /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */
431 if (dccp_sk(sk
)->dccps_l_ack_ratio
> hc
->tx_cwnd
)
432 ccid2_change_l_ack_ratio(sk
, hc
->tx_cwnd
);
435 static void ccid2_hc_tx_packet_recv(struct sock
*sk
, struct sk_buff
*skb
)
437 struct dccp_sock
*dp
= dccp_sk(sk
);
438 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
439 const bool sender_was_blocked
= ccid2_cwnd_network_limited(hc
);
441 struct ccid2_seq
*seqp
;
442 unsigned char *vector
;
443 unsigned char veclen
;
446 unsigned int maxincr
= 0;
448 /* check reverse path congestion */
449 seqno
= DCCP_SKB_CB(skb
)->dccpd_seq
;
451 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
452 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
455 /* need to bootstrap */
456 if (hc
->tx_rpdupack
== -1) {
458 hc
->tx_rpseq
= seqno
;
460 /* check if packet is consecutive */
461 if (dccp_delta_seqno(hc
->tx_rpseq
, seqno
) == 1)
462 hc
->tx_rpseq
= seqno
;
463 /* it's a later packet */
464 else if (after48(seqno
, hc
->tx_rpseq
)) {
467 /* check if we got enough dupacks */
468 if (hc
->tx_rpdupack
>= NUMDUPACK
) {
469 hc
->tx_rpdupack
= -1; /* XXX lame */
472 ccid2_change_l_ack_ratio(sk
, 2 * dp
->dccps_l_ack_ratio
);
477 /* check forward path congestion */
478 /* still didn't send out new data packets */
479 if (hc
->tx_seqh
== hc
->tx_seqt
)
482 switch (DCCP_SKB_CB(skb
)->dccpd_type
) {
484 case DCCP_PKT_DATAACK
:
490 ackno
= DCCP_SKB_CB(skb
)->dccpd_ack_seq
;
491 if (after48(ackno
, hc
->tx_high_ack
))
492 hc
->tx_high_ack
= ackno
;
495 while (before48(seqp
->ccid2s_seq
, ackno
)) {
496 seqp
= seqp
->ccid2s_next
;
497 if (seqp
== hc
->tx_seqh
) {
498 seqp
= hc
->tx_seqh
->ccid2s_prev
;
504 * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2
505 * packets per acknowledgement. Rounding up avoids that cwnd is not
506 * advanced when Ack Ratio is 1 and gives a slight edge otherwise.
508 if (hc
->tx_cwnd
< hc
->tx_ssthresh
)
509 maxincr
= DIV_ROUND_UP(dp
->dccps_l_ack_ratio
, 2);
511 /* go through all ack vectors */
512 while ((offset
= ccid2_ackvector(sk
, skb
, offset
,
513 &vector
, &veclen
)) != -1) {
514 /* go through this ack vector */
516 const u8 rl
= *vector
& DCCP_ACKVEC_LEN_MASK
;
517 u64 ackno_end_rl
= SUB48(ackno
, rl
);
519 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
520 (unsigned long long)ackno
,
521 (unsigned long long)ackno_end_rl
);
522 /* if the seqno we are analyzing is larger than the
523 * current ackno, then move towards the tail of our
526 while (after48(seqp
->ccid2s_seq
, ackno
)) {
527 if (seqp
== hc
->tx_seqt
) {
531 seqp
= seqp
->ccid2s_prev
;
536 /* check all seqnos in the range of the vector
539 while (between48(seqp
->ccid2s_seq
,ackno_end_rl
,ackno
)) {
540 const u8 state
= *vector
&
541 DCCP_ACKVEC_STATE_MASK
;
543 /* new packet received or marked */
544 if (state
!= DCCP_ACKVEC_STATE_NOT_RECEIVED
&&
545 !seqp
->ccid2s_acked
) {
547 DCCP_ACKVEC_STATE_ECN_MARKED
) {
548 ccid2_congestion_event(sk
,
551 ccid2_new_ack(sk
, seqp
,
554 seqp
->ccid2s_acked
= 1;
555 ccid2_pr_debug("Got ack for %llu\n",
556 (unsigned long long)seqp
->ccid2s_seq
);
559 if (seqp
== hc
->tx_seqt
) {
563 seqp
= seqp
->ccid2s_prev
;
568 ackno
= SUB48(ackno_end_rl
, 1);
575 /* The state about what is acked should be correct now
576 * Check for NUMDUPACK
579 while (before48(seqp
->ccid2s_seq
, hc
->tx_high_ack
)) {
580 seqp
= seqp
->ccid2s_next
;
581 if (seqp
== hc
->tx_seqh
) {
582 seqp
= hc
->tx_seqh
->ccid2s_prev
;
588 if (seqp
->ccid2s_acked
) {
590 if (done
== NUMDUPACK
)
593 if (seqp
== hc
->tx_seqt
)
595 seqp
= seqp
->ccid2s_prev
;
598 /* If there are at least 3 acknowledgements, anything unacknowledged
599 * below the last sequence number is considered lost
601 if (done
== NUMDUPACK
) {
602 struct ccid2_seq
*last_acked
= seqp
;
604 /* check for lost packets */
606 if (!seqp
->ccid2s_acked
) {
607 ccid2_pr_debug("Packet lost: %llu\n",
608 (unsigned long long)seqp
->ccid2s_seq
);
609 /* XXX need to traverse from tail -> head in
610 * order to detect multiple congestion events in
613 ccid2_congestion_event(sk
, seqp
);
616 if (seqp
== hc
->tx_seqt
)
618 seqp
= seqp
->ccid2s_prev
;
621 hc
->tx_seqt
= last_acked
;
624 /* trim acked packets in tail */
625 while (hc
->tx_seqt
!= hc
->tx_seqh
) {
626 if (!hc
->tx_seqt
->ccid2s_acked
)
629 hc
->tx_seqt
= hc
->tx_seqt
->ccid2s_next
;
632 /* restart RTO timer if not all outstanding data has been acked */
633 if (hc
->tx_pipe
== 0)
634 sk_stop_timer(sk
, &hc
->tx_rtotimer
);
636 sk_reset_timer(sk
, &hc
->tx_rtotimer
, jiffies
+ hc
->tx_rto
);
638 /* check if incoming Acks allow pending packets to be sent */
639 if (sender_was_blocked
&& !ccid2_cwnd_network_limited(hc
))
640 tasklet_schedule(&dccp_sk(sk
)->dccps_xmitlet
);
643 static int ccid2_hc_tx_init(struct ccid
*ccid
, struct sock
*sk
)
645 struct ccid2_hc_tx_sock
*hc
= ccid_priv(ccid
);
646 struct dccp_sock
*dp
= dccp_sk(sk
);
649 /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
650 hc
->tx_ssthresh
= ~0U;
652 /* Use larger initial windows (RFC 4341, section 5). */
653 hc
->tx_cwnd
= rfc3390_bytes_to_packets(dp
->dccps_mss_cache
);
655 /* Make sure that Ack Ratio is enabled and within bounds. */
656 max_ratio
= DIV_ROUND_UP(hc
->tx_cwnd
, 2);
657 if (dp
->dccps_l_ack_ratio
== 0 || dp
->dccps_l_ack_ratio
> max_ratio
)
658 dp
->dccps_l_ack_ratio
= max_ratio
;
660 /* XXX init ~ to window size... */
661 if (ccid2_hc_tx_alloc_seq(hc
))
664 hc
->tx_rto
= DCCP_TIMEOUT_INIT
;
665 hc
->tx_rpdupack
= -1;
666 hc
->tx_last_cong
= ccid2_time_stamp
;
667 setup_timer(&hc
->tx_rtotimer
, ccid2_hc_tx_rto_expire
,
672 static void ccid2_hc_tx_exit(struct sock
*sk
)
674 struct ccid2_hc_tx_sock
*hc
= ccid2_hc_tx_sk(sk
);
677 sk_stop_timer(sk
, &hc
->tx_rtotimer
);
679 for (i
= 0; i
< hc
->tx_seqbufc
; i
++)
680 kfree(hc
->tx_seqbuf
[i
]);
684 static void ccid2_hc_rx_packet_recv(struct sock
*sk
, struct sk_buff
*skb
)
686 const struct dccp_sock
*dp
= dccp_sk(sk
);
687 struct ccid2_hc_rx_sock
*hc
= ccid2_hc_rx_sk(sk
);
689 switch (DCCP_SKB_CB(skb
)->dccpd_type
) {
691 case DCCP_PKT_DATAACK
:
693 if (hc
->rx_data
>= dp
->dccps_r_ack_ratio
) {
701 struct ccid_operations ccid2_ops
= {
702 .ccid_id
= DCCPC_CCID2
,
703 .ccid_name
= "TCP-like",
704 .ccid_hc_tx_obj_size
= sizeof(struct ccid2_hc_tx_sock
),
705 .ccid_hc_tx_init
= ccid2_hc_tx_init
,
706 .ccid_hc_tx_exit
= ccid2_hc_tx_exit
,
707 .ccid_hc_tx_send_packet
= ccid2_hc_tx_send_packet
,
708 .ccid_hc_tx_packet_sent
= ccid2_hc_tx_packet_sent
,
709 .ccid_hc_tx_packet_recv
= ccid2_hc_tx_packet_recv
,
710 .ccid_hc_rx_obj_size
= sizeof(struct ccid2_hc_rx_sock
),
711 .ccid_hc_rx_packet_recv
= ccid2_hc_rx_packet_recv
,
714 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
715 module_param(ccid2_debug
, bool, 0644);
716 MODULE_PARM_DESC(ccid2_debug
, "Enable CCID-2 debug messages");