2 * net/dccp/ccids/ccid2.c
4 * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
6 * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
8 * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 * This implementation should follow RFC 4341
29 * - sequence number wrapping
37 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
38 static int ccid2_debug
;
39 #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
41 static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock
*hctx
)
45 struct ccid2_seq
*seqp
= hctx
->ccid2hctx_seqh
;
47 /* there is data in the chain */
48 if (seqp
!= hctx
->ccid2hctx_seqt
) {
49 seqp
= seqp
->ccid2s_prev
;
51 if (!seqp
->ccid2s_acked
)
54 while (seqp
!= hctx
->ccid2hctx_seqt
) {
55 struct ccid2_seq
*prev
= seqp
->ccid2s_prev
;
58 if (!prev
->ccid2s_acked
)
61 /* packets are sent sequentially */
62 BUG_ON(seqp
->ccid2s_seq
<= prev
->ccid2s_seq
);
63 BUG_ON(time_before(seqp
->ccid2s_sent
,
70 BUG_ON(pipe
!= hctx
->ccid2hctx_pipe
);
71 ccid2_pr_debug("len of chain=%d\n", len
);
74 seqp
= seqp
->ccid2s_prev
;
76 } while (seqp
!= hctx
->ccid2hctx_seqh
);
78 ccid2_pr_debug("total len=%d\n", len
);
79 BUG_ON(len
!= hctx
->ccid2hctx_seqbufc
* CCID2_SEQBUF_LEN
);
82 #define ccid2_pr_debug(format, a...)
83 #define ccid2_hc_tx_check_sanity(hctx)
86 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock
*hctx
)
88 struct ccid2_seq
*seqp
;
91 /* check if we have space to preserve the pointer to the buffer */
92 if (hctx
->ccid2hctx_seqbufc
>= (sizeof(hctx
->ccid2hctx_seqbuf
) /
93 sizeof(struct ccid2_seq
*)))
96 /* allocate buffer and initialize linked list */
97 seqp
= kmalloc(CCID2_SEQBUF_LEN
* sizeof(struct ccid2_seq
), gfp_any());
101 for (i
= 0; i
< (CCID2_SEQBUF_LEN
- 1); i
++) {
102 seqp
[i
].ccid2s_next
= &seqp
[i
+ 1];
103 seqp
[i
+ 1].ccid2s_prev
= &seqp
[i
];
105 seqp
[CCID2_SEQBUF_LEN
- 1].ccid2s_next
= seqp
;
106 seqp
->ccid2s_prev
= &seqp
[CCID2_SEQBUF_LEN
- 1];
108 /* This is the first allocation. Initiate the head and tail. */
109 if (hctx
->ccid2hctx_seqbufc
== 0)
110 hctx
->ccid2hctx_seqh
= hctx
->ccid2hctx_seqt
= seqp
;
112 /* link the existing list with the one we just created */
113 hctx
->ccid2hctx_seqh
->ccid2s_next
= seqp
;
114 seqp
->ccid2s_prev
= hctx
->ccid2hctx_seqh
;
116 hctx
->ccid2hctx_seqt
->ccid2s_prev
= &seqp
[CCID2_SEQBUF_LEN
- 1];
117 seqp
[CCID2_SEQBUF_LEN
- 1].ccid2s_next
= hctx
->ccid2hctx_seqt
;
120 /* store the original pointer to the buffer so we can free it */
121 hctx
->ccid2hctx_seqbuf
[hctx
->ccid2hctx_seqbufc
] = seqp
;
122 hctx
->ccid2hctx_seqbufc
++;
127 static int ccid2_hc_tx_send_packet(struct sock
*sk
, struct sk_buff
*skb
)
129 struct ccid2_hc_tx_sock
*hctx
;
131 switch (DCCP_SKB_CB(skb
)->dccpd_type
) {
132 case 0: /* XXX data packets from userland come through like this */
134 case DCCP_PKT_DATAACK
:
136 /* No congestion control on other packets */
141 hctx
= ccid2_hc_tx_sk(sk
);
143 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx
->ccid2hctx_pipe
,
144 hctx
->ccid2hctx_cwnd
);
146 if (hctx
->ccid2hctx_pipe
< hctx
->ccid2hctx_cwnd
) {
147 /* OK we can send... make sure previous packet was sent off */
148 if (!hctx
->ccid2hctx_sendwait
) {
149 hctx
->ccid2hctx_sendwait
= 1;
154 return 1; /* XXX CCID should dequeue when ready instead of polling */
157 static void ccid2_change_l_ack_ratio(struct sock
*sk
, int val
)
159 struct dccp_sock
*dp
= dccp_sk(sk
);
161 * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
162 * should be 1... it shouldn't be allowed to become 2.
166 const struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
167 int max
= hctx
->ccid2hctx_cwnd
/ 2;
170 if (hctx
->ccid2hctx_cwnd
& 1)
177 ccid2_pr_debug("changing local ack ratio to %d\n", val
);
179 dp
->dccps_l_ack_ratio
= val
;
182 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock
*hctx
, u32 val
)
184 /* XXX do we need to change ack ratio? */
185 hctx
->ccid2hctx_cwnd
= val
? : 1;
186 ccid2_pr_debug("changed cwnd to %u\n", hctx
->ccid2hctx_cwnd
);
189 static void ccid2_change_srtt(struct ccid2_hc_tx_sock
*hctx
, long val
)
191 ccid2_pr_debug("change SRTT to %ld\n", val
);
192 hctx
->ccid2hctx_srtt
= val
;
195 static void ccid2_change_pipe(struct ccid2_hc_tx_sock
*hctx
, long val
)
197 hctx
->ccid2hctx_pipe
= val
;
200 static void ccid2_start_rto_timer(struct sock
*sk
);
202 static void ccid2_hc_tx_rto_expire(unsigned long data
)
204 struct sock
*sk
= (struct sock
*)data
;
205 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
209 if (sock_owned_by_user(sk
)) {
210 sk_reset_timer(sk
, &hctx
->ccid2hctx_rtotimer
,
215 ccid2_pr_debug("RTO_EXPIRE\n");
217 ccid2_hc_tx_check_sanity(hctx
);
220 hctx
->ccid2hctx_rto
<<= 1;
222 s
= hctx
->ccid2hctx_rto
/ HZ
;
224 hctx
->ccid2hctx_rto
= 60 * HZ
;
226 ccid2_start_rto_timer(sk
);
228 /* adjust pipe, cwnd etc */
229 ccid2_change_pipe(hctx
, 0);
230 hctx
->ccid2hctx_ssthresh
= hctx
->ccid2hctx_cwnd
>> 1;
231 if (hctx
->ccid2hctx_ssthresh
< 2)
232 hctx
->ccid2hctx_ssthresh
= 2;
233 ccid2_change_cwnd(hctx
, 1);
235 /* clear state about stuff we sent */
236 hctx
->ccid2hctx_seqt
= hctx
->ccid2hctx_seqh
;
237 hctx
->ccid2hctx_ssacks
= 0;
238 hctx
->ccid2hctx_acks
= 0;
239 hctx
->ccid2hctx_sent
= 0;
241 /* clear ack ratio state. */
242 hctx
->ccid2hctx_arsent
= 0;
243 hctx
->ccid2hctx_ackloss
= 0;
244 hctx
->ccid2hctx_rpseq
= 0;
245 hctx
->ccid2hctx_rpdupack
= -1;
246 ccid2_change_l_ack_ratio(sk
, 1);
247 ccid2_hc_tx_check_sanity(hctx
);
253 static void ccid2_start_rto_timer(struct sock
*sk
)
255 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
257 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx
->ccid2hctx_rto
);
259 BUG_ON(timer_pending(&hctx
->ccid2hctx_rtotimer
));
260 sk_reset_timer(sk
, &hctx
->ccid2hctx_rtotimer
,
261 jiffies
+ hctx
->ccid2hctx_rto
);
264 static void ccid2_hc_tx_packet_sent(struct sock
*sk
, int more
, unsigned int len
)
266 struct dccp_sock
*dp
= dccp_sk(sk
);
267 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
268 struct ccid2_seq
*next
;
271 ccid2_hc_tx_check_sanity(hctx
);
273 BUG_ON(!hctx
->ccid2hctx_sendwait
);
274 hctx
->ccid2hctx_sendwait
= 0;
275 ccid2_change_pipe(hctx
, hctx
->ccid2hctx_pipe
+ 1);
276 BUG_ON(hctx
->ccid2hctx_pipe
< 0);
278 /* There is an issue. What if another packet is sent between
279 * packet_send() and packet_sent(). Then the sequence number would be
285 hctx
->ccid2hctx_seqh
->ccid2s_seq
= seq
;
286 hctx
->ccid2hctx_seqh
->ccid2s_acked
= 0;
287 hctx
->ccid2hctx_seqh
->ccid2s_sent
= jiffies
;
289 next
= hctx
->ccid2hctx_seqh
->ccid2s_next
;
290 /* check if we need to alloc more space */
291 if (next
== hctx
->ccid2hctx_seqt
) {
292 if (ccid2_hc_tx_alloc_seq(hctx
)) {
293 DCCP_CRIT("packet history - out of memory!");
294 /* FIXME: find a more graceful way to bail out */
297 next
= hctx
->ccid2hctx_seqh
->ccid2s_next
;
298 BUG_ON(next
== hctx
->ccid2hctx_seqt
);
300 hctx
->ccid2hctx_seqh
= next
;
302 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx
->ccid2hctx_cwnd
,
303 hctx
->ccid2hctx_pipe
);
305 hctx
->ccid2hctx_sent
++;
307 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
308 hctx
->ccid2hctx_arsent
++;
309 /* We had an ack loss in this window... */
310 if (hctx
->ccid2hctx_ackloss
) {
311 if (hctx
->ccid2hctx_arsent
>= hctx
->ccid2hctx_cwnd
) {
312 hctx
->ccid2hctx_arsent
= 0;
313 hctx
->ccid2hctx_ackloss
= 0;
316 /* No acks lost up to now... */
317 /* decrease ack ratio if enough packets were sent */
318 if (dp
->dccps_l_ack_ratio
> 1) {
319 /* XXX don't calculate denominator each time */
320 int denom
= dp
->dccps_l_ack_ratio
* dp
->dccps_l_ack_ratio
-
321 dp
->dccps_l_ack_ratio
;
323 denom
= hctx
->ccid2hctx_cwnd
* hctx
->ccid2hctx_cwnd
/ denom
;
325 if (hctx
->ccid2hctx_arsent
>= denom
) {
326 ccid2_change_l_ack_ratio(sk
, dp
->dccps_l_ack_ratio
- 1);
327 hctx
->ccid2hctx_arsent
= 0;
330 /* we can't increase ack ratio further [1] */
331 hctx
->ccid2hctx_arsent
= 0; /* or maybe set it to cwnd*/
335 /* setup RTO timer */
336 if (!timer_pending(&hctx
->ccid2hctx_rtotimer
))
337 ccid2_start_rto_timer(sk
);
339 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
340 ccid2_pr_debug("pipe=%d\n", hctx
->ccid2hctx_pipe
);
341 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq
);
343 struct ccid2_seq
*seqp
= hctx
->ccid2hctx_seqt
;
345 while (seqp
!= hctx
->ccid2hctx_seqh
) {
346 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
347 (unsigned long long)seqp
->ccid2s_seq
,
348 seqp
->ccid2s_acked
, seqp
->ccid2s_sent
);
349 seqp
= seqp
->ccid2s_next
;
352 ccid2_pr_debug("=========\n");
353 ccid2_hc_tx_check_sanity(hctx
);
357 /* XXX Lame code duplication!
358 * returns -1 if none was found.
359 * else returns the next offset to use in the function call.
361 static int ccid2_ackvector(struct sock
*sk
, struct sk_buff
*skb
, int offset
,
362 unsigned char **vec
, unsigned char *veclen
)
364 const struct dccp_hdr
*dh
= dccp_hdr(skb
);
365 unsigned char *options
= (unsigned char *)dh
+ dccp_hdr_len(skb
);
366 unsigned char *opt_ptr
;
367 const unsigned char *opt_end
= (unsigned char *)dh
+
368 (dh
->dccph_doff
* 4);
369 unsigned char opt
, len
;
370 unsigned char *value
;
375 if (opt_ptr
>= opt_end
)
378 while (opt_ptr
!= opt_end
) {
383 /* Check if this isn't a single byte option */
384 if (opt
> DCCPO_MAX_RESERVED
) {
385 if (opt_ptr
== opt_end
)
386 goto out_invalid_option
;
390 goto out_invalid_option
;
392 * Remove the type and len fields, leaving
393 * just the value size
399 if (opt_ptr
> opt_end
)
400 goto out_invalid_option
;
404 case DCCPO_ACK_VECTOR_0
:
405 case DCCPO_ACK_VECTOR_1
:
408 return offset
+ (opt_ptr
- options
);
415 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
419 static void ccid2_hc_tx_kill_rto_timer(struct sock
*sk
)
421 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
423 sk_stop_timer(sk
, &hctx
->ccid2hctx_rtotimer
);
424 ccid2_pr_debug("deleted RTO timer\n");
427 static inline void ccid2_new_ack(struct sock
*sk
,
428 struct ccid2_seq
*seqp
,
429 unsigned int *maxincr
)
431 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
434 if (hctx
->ccid2hctx_cwnd
< hctx
->ccid2hctx_ssthresh
) {
435 hctx
->ccid2hctx_acks
= 0;
437 /* We can increase cwnd at most maxincr [ack_ratio/2] */
439 /* increase every 2 acks */
440 hctx
->ccid2hctx_ssacks
++;
441 if (hctx
->ccid2hctx_ssacks
== 2) {
442 ccid2_change_cwnd(hctx
, hctx
->ccid2hctx_cwnd
+1);
443 hctx
->ccid2hctx_ssacks
= 0;
444 *maxincr
= *maxincr
- 1;
447 /* increased cwnd enough for this single ack */
448 hctx
->ccid2hctx_ssacks
= 0;
451 hctx
->ccid2hctx_ssacks
= 0;
452 hctx
->ccid2hctx_acks
++;
454 if (hctx
->ccid2hctx_acks
>= hctx
->ccid2hctx_cwnd
) {
455 ccid2_change_cwnd(hctx
, hctx
->ccid2hctx_cwnd
+ 1);
456 hctx
->ccid2hctx_acks
= 0;
461 if (hctx
->ccid2hctx_srtt
== -1 ||
462 time_after(jiffies
, hctx
->ccid2hctx_lastrtt
+ hctx
->ccid2hctx_srtt
)) {
463 unsigned long r
= (long)jiffies
- (long)seqp
->ccid2s_sent
;
466 /* first measurement */
467 if (hctx
->ccid2hctx_srtt
== -1) {
468 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
470 (unsigned long long)seqp
->ccid2s_seq
);
471 ccid2_change_srtt(hctx
, r
);
472 hctx
->ccid2hctx_rttvar
= r
>> 1;
475 long tmp
= hctx
->ccid2hctx_srtt
- r
;
482 hctx
->ccid2hctx_rttvar
*= 3;
483 hctx
->ccid2hctx_rttvar
>>= 2;
484 hctx
->ccid2hctx_rttvar
+= tmp
;
487 srtt
= hctx
->ccid2hctx_srtt
;
492 ccid2_change_srtt(hctx
, srtt
);
494 s
= hctx
->ccid2hctx_rttvar
<< 2;
495 /* clock granularity is 1 when based on jiffies */
498 hctx
->ccid2hctx_rto
= hctx
->ccid2hctx_srtt
+ s
;
500 /* must be at least a second */
501 s
= hctx
->ccid2hctx_rto
/ HZ
;
502 /* DCCP doesn't require this [but I like it cuz my code sux] */
505 hctx
->ccid2hctx_rto
= HZ
;
509 hctx
->ccid2hctx_rto
= HZ
* 60;
511 hctx
->ccid2hctx_lastrtt
= jiffies
;
513 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
514 hctx
->ccid2hctx_srtt
, hctx
->ccid2hctx_rttvar
,
515 hctx
->ccid2hctx_rto
, HZ
, r
);
516 hctx
->ccid2hctx_sent
= 0;
519 /* we got a new ack, so re-start RTO timer */
520 ccid2_hc_tx_kill_rto_timer(sk
);
521 ccid2_start_rto_timer(sk
);
524 static void ccid2_hc_tx_dec_pipe(struct sock
*sk
)
526 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
528 ccid2_change_pipe(hctx
, hctx
->ccid2hctx_pipe
-1);
529 BUG_ON(hctx
->ccid2hctx_pipe
< 0);
531 if (hctx
->ccid2hctx_pipe
== 0)
532 ccid2_hc_tx_kill_rto_timer(sk
);
535 static void ccid2_congestion_event(struct ccid2_hc_tx_sock
*hctx
,
536 struct ccid2_seq
*seqp
)
538 if (time_before(seqp
->ccid2s_sent
, hctx
->ccid2hctx_last_cong
)) {
539 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
543 hctx
->ccid2hctx_last_cong
= jiffies
;
545 ccid2_change_cwnd(hctx
, hctx
->ccid2hctx_cwnd
>> 1);
546 hctx
->ccid2hctx_ssthresh
= hctx
->ccid2hctx_cwnd
;
547 if (hctx
->ccid2hctx_ssthresh
< 2)
548 hctx
->ccid2hctx_ssthresh
= 2;
551 static void ccid2_hc_tx_packet_recv(struct sock
*sk
, struct sk_buff
*skb
)
553 struct dccp_sock
*dp
= dccp_sk(sk
);
554 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
556 struct ccid2_seq
*seqp
;
557 unsigned char *vector
;
558 unsigned char veclen
;
561 unsigned int maxincr
= 0;
563 ccid2_hc_tx_check_sanity(hctx
);
564 /* check reverse path congestion */
565 seqno
= DCCP_SKB_CB(skb
)->dccpd_seq
;
567 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
568 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
571 /* need to bootstrap */
572 if (hctx
->ccid2hctx_rpdupack
== -1) {
573 hctx
->ccid2hctx_rpdupack
= 0;
574 hctx
->ccid2hctx_rpseq
= seqno
;
576 /* check if packet is consecutive */
577 if ((hctx
->ccid2hctx_rpseq
+ 1) == seqno
)
578 hctx
->ccid2hctx_rpseq
++;
579 /* it's a later packet */
580 else if (after48(seqno
, hctx
->ccid2hctx_rpseq
)) {
581 hctx
->ccid2hctx_rpdupack
++;
583 /* check if we got enough dupacks */
584 if (hctx
->ccid2hctx_rpdupack
>=
585 hctx
->ccid2hctx_numdupack
) {
586 hctx
->ccid2hctx_rpdupack
= -1; /* XXX lame */
587 hctx
->ccid2hctx_rpseq
= 0;
589 ccid2_change_l_ack_ratio(sk
, dp
->dccps_l_ack_ratio
<< 1);
594 /* check forward path congestion */
595 /* still didn't send out new data packets */
596 if (hctx
->ccid2hctx_seqh
== hctx
->ccid2hctx_seqt
)
599 switch (DCCP_SKB_CB(skb
)->dccpd_type
) {
601 case DCCP_PKT_DATAACK
:
607 ackno
= DCCP_SKB_CB(skb
)->dccpd_ack_seq
;
608 if (after48(ackno
, hctx
->ccid2hctx_high_ack
))
609 hctx
->ccid2hctx_high_ack
= ackno
;
611 seqp
= hctx
->ccid2hctx_seqt
;
612 while (before48(seqp
->ccid2s_seq
, ackno
)) {
613 seqp
= seqp
->ccid2s_next
;
614 if (seqp
== hctx
->ccid2hctx_seqh
) {
615 seqp
= hctx
->ccid2hctx_seqh
->ccid2s_prev
;
620 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
621 * this single ack. I round up.
624 maxincr
= dp
->dccps_l_ack_ratio
>> 1;
627 /* go through all ack vectors */
628 while ((offset
= ccid2_ackvector(sk
, skb
, offset
,
629 &vector
, &veclen
)) != -1) {
630 /* go through this ack vector */
632 const u8 rl
= *vector
& DCCP_ACKVEC_LEN_MASK
;
635 dccp_set_seqno(&ackno_end_rl
, ackno
- rl
);
636 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
637 (unsigned long long)ackno
,
638 (unsigned long long)ackno_end_rl
);
639 /* if the seqno we are analyzing is larger than the
640 * current ackno, then move towards the tail of our
643 while (after48(seqp
->ccid2s_seq
, ackno
)) {
644 if (seqp
== hctx
->ccid2hctx_seqt
) {
648 seqp
= seqp
->ccid2s_prev
;
653 /* check all seqnos in the range of the vector
656 while (between48(seqp
->ccid2s_seq
,ackno_end_rl
,ackno
)) {
657 const u8 state
= *vector
&
658 DCCP_ACKVEC_STATE_MASK
;
660 /* new packet received or marked */
661 if (state
!= DCCP_ACKVEC_STATE_NOT_RECEIVED
&&
662 !seqp
->ccid2s_acked
) {
664 DCCP_ACKVEC_STATE_ECN_MARKED
) {
665 ccid2_congestion_event(hctx
,
668 ccid2_new_ack(sk
, seqp
,
671 seqp
->ccid2s_acked
= 1;
672 ccid2_pr_debug("Got ack for %llu\n",
673 (unsigned long long)seqp
->ccid2s_seq
);
674 ccid2_hc_tx_dec_pipe(sk
);
676 if (seqp
== hctx
->ccid2hctx_seqt
) {
680 seqp
= seqp
->ccid2s_next
;
686 dccp_set_seqno(&ackno
, ackno_end_rl
- 1);
693 /* The state about what is acked should be correct now
694 * Check for NUMDUPACK
696 seqp
= hctx
->ccid2hctx_seqt
;
697 while (before48(seqp
->ccid2s_seq
, hctx
->ccid2hctx_high_ack
)) {
698 seqp
= seqp
->ccid2s_next
;
699 if (seqp
== hctx
->ccid2hctx_seqh
) {
700 seqp
= hctx
->ccid2hctx_seqh
->ccid2s_prev
;
706 if (seqp
->ccid2s_acked
) {
708 if (done
== hctx
->ccid2hctx_numdupack
)
711 if (seqp
== hctx
->ccid2hctx_seqt
)
713 seqp
= seqp
->ccid2s_prev
;
716 /* If there are at least 3 acknowledgements, anything unacknowledged
717 * below the last sequence number is considered lost
719 if (done
== hctx
->ccid2hctx_numdupack
) {
720 struct ccid2_seq
*last_acked
= seqp
;
722 /* check for lost packets */
724 if (!seqp
->ccid2s_acked
) {
725 ccid2_pr_debug("Packet lost: %llu\n",
726 (unsigned long long)seqp
->ccid2s_seq
);
727 /* XXX need to traverse from tail -> head in
728 * order to detect multiple congestion events in
731 ccid2_congestion_event(hctx
, seqp
);
732 ccid2_hc_tx_dec_pipe(sk
);
734 if (seqp
== hctx
->ccid2hctx_seqt
)
736 seqp
= seqp
->ccid2s_prev
;
739 hctx
->ccid2hctx_seqt
= last_acked
;
742 /* trim acked packets in tail */
743 while (hctx
->ccid2hctx_seqt
!= hctx
->ccid2hctx_seqh
) {
744 if (!hctx
->ccid2hctx_seqt
->ccid2s_acked
)
747 hctx
->ccid2hctx_seqt
= hctx
->ccid2hctx_seqt
->ccid2s_next
;
750 ccid2_hc_tx_check_sanity(hctx
);
753 static int ccid2_hc_tx_init(struct ccid
*ccid
, struct sock
*sk
)
755 struct ccid2_hc_tx_sock
*hctx
= ccid_priv(ccid
);
757 ccid2_change_cwnd(hctx
, 1);
758 /* Initialize ssthresh to infinity. This means that we will exit the
759 * initial slow-start after the first packet loss. This is what we
762 hctx
->ccid2hctx_ssthresh
= ~0;
763 hctx
->ccid2hctx_numdupack
= 3;
764 hctx
->ccid2hctx_seqbufc
= 0;
766 /* XXX init ~ to window size... */
767 if (ccid2_hc_tx_alloc_seq(hctx
))
770 hctx
->ccid2hctx_sent
= 0;
771 hctx
->ccid2hctx_rto
= 3 * HZ
;
772 ccid2_change_srtt(hctx
, -1);
773 hctx
->ccid2hctx_rttvar
= -1;
774 hctx
->ccid2hctx_lastrtt
= 0;
775 hctx
->ccid2hctx_rpdupack
= -1;
776 hctx
->ccid2hctx_last_cong
= jiffies
;
777 hctx
->ccid2hctx_high_ack
= 0;
779 hctx
->ccid2hctx_rtotimer
.function
= &ccid2_hc_tx_rto_expire
;
780 hctx
->ccid2hctx_rtotimer
.data
= (unsigned long)sk
;
781 init_timer(&hctx
->ccid2hctx_rtotimer
);
783 ccid2_hc_tx_check_sanity(hctx
);
787 static void ccid2_hc_tx_exit(struct sock
*sk
)
789 struct ccid2_hc_tx_sock
*hctx
= ccid2_hc_tx_sk(sk
);
792 ccid2_hc_tx_kill_rto_timer(sk
);
794 for (i
= 0; i
< hctx
->ccid2hctx_seqbufc
; i
++)
795 kfree(hctx
->ccid2hctx_seqbuf
[i
]);
796 hctx
->ccid2hctx_seqbufc
= 0;
799 static void ccid2_hc_rx_packet_recv(struct sock
*sk
, struct sk_buff
*skb
)
801 const struct dccp_sock
*dp
= dccp_sk(sk
);
802 struct ccid2_hc_rx_sock
*hcrx
= ccid2_hc_rx_sk(sk
);
804 switch (DCCP_SKB_CB(skb
)->dccpd_type
) {
806 case DCCP_PKT_DATAACK
:
807 hcrx
->ccid2hcrx_data
++;
808 if (hcrx
->ccid2hcrx_data
>= dp
->dccps_r_ack_ratio
) {
810 hcrx
->ccid2hcrx_data
= 0;
816 static struct ccid_operations ccid2
= {
817 .ccid_id
= DCCPC_CCID2
,
818 .ccid_name
= "ccid2",
819 .ccid_owner
= THIS_MODULE
,
820 .ccid_hc_tx_obj_size
= sizeof(struct ccid2_hc_tx_sock
),
821 .ccid_hc_tx_init
= ccid2_hc_tx_init
,
822 .ccid_hc_tx_exit
= ccid2_hc_tx_exit
,
823 .ccid_hc_tx_send_packet
= ccid2_hc_tx_send_packet
,
824 .ccid_hc_tx_packet_sent
= ccid2_hc_tx_packet_sent
,
825 .ccid_hc_tx_packet_recv
= ccid2_hc_tx_packet_recv
,
826 .ccid_hc_rx_obj_size
= sizeof(struct ccid2_hc_rx_sock
),
827 .ccid_hc_rx_packet_recv
= ccid2_hc_rx_packet_recv
,
830 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
831 module_param(ccid2_debug
, bool, 0444);
832 MODULE_PARM_DESC(ccid2_debug
, "Enable debug messages");
835 static __init
int ccid2_module_init(void)
837 return ccid_register(&ccid2
);
839 module_init(ccid2_module_init
);
841 static __exit
void ccid2_module_exit(void)
843 ccid_unregister(&ccid2
);
845 module_exit(ccid2_module_exit
);
847 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
848 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
849 MODULE_LICENSE("GPL");
850 MODULE_ALIAS("net-dccp-ccid-2");