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-rw-r--r--net/dccp/options.c887
1 files changed, 887 insertions, 0 deletions
diff --git a/net/dccp/options.c b/net/dccp/options.c
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1/*
2 * net/dccp/options.c
3 *
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 <iam4@cs.waikato.ac.nz>
8 *
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.
13 */
14#include <linux/config.h>
15#include <linux/dccp.h>
16#include <linux/module.h>
17#include <linux/types.h>
18#include <linux/kernel.h>
19#include <linux/skbuff.h>
20
21#include "ccid.h"
22#include "dccp.h"
23
24static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
25 struct sock *sk,
26 const u64 ackno,
27 const unsigned char len,
28 const unsigned char *vector);
29
30/* stores the default values for new connection. may be changed with sysctl */
31static const struct dccp_options dccpo_default_values = {
32 .dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
33 .dccpo_ccid = DCCPF_INITIAL_CCID,
34 .dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
35 .dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
36};
37
38void dccp_options_init(struct dccp_options *dccpo)
39{
40 memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
41}
42
43static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
44{
45 u32 value = 0;
46
47 if (len > 3)
48 value += *bf++ << 24;
49 if (len > 2)
50 value += *bf++ << 16;
51 if (len > 1)
52 value += *bf++ << 8;
53 if (len > 0)
54 value += *bf;
55
56 return value;
57}
58
59int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
60{
61 struct dccp_sock *dp = dccp_sk(sk);
62#ifdef CONFIG_IP_DCCP_DEBUG
63 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
64 "CLIENT rx opt: " : "server rx opt: ";
65#endif
66 const struct dccp_hdr *dh = dccp_hdr(skb);
67 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
68 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
69 unsigned char *opt_ptr = options;
70 const unsigned char *opt_end = (unsigned char *)dh +
71 (dh->dccph_doff * 4);
72 struct dccp_options_received *opt_recv = &dp->dccps_options_received;
73 unsigned char opt, len;
74 unsigned char *value;
75 u32 elapsed_time;
76
77 memset(opt_recv, 0, sizeof(*opt_recv));
78
79 while (opt_ptr != opt_end) {
80 opt = *opt_ptr++;
81 len = 0;
82 value = NULL;
83
84 /* Check if this isn't a single byte option */
85 if (opt > DCCPO_MAX_RESERVED) {
86 if (opt_ptr == opt_end)
87 goto out_invalid_option;
88
89 len = *opt_ptr++;
90 if (len < 3)
91 goto out_invalid_option;
92 /*
93 * Remove the type and len fields, leaving
94 * just the value size
95 */
96 len -= 2;
97 value = opt_ptr;
98 opt_ptr += len;
99
100 if (opt_ptr > opt_end)
101 goto out_invalid_option;
102 }
103
104 switch (opt) {
105 case DCCPO_PADDING:
106 break;
107 case DCCPO_NDP_COUNT:
108 if (len > 3)
109 goto out_invalid_option;
110
111 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
112 dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
113 opt_recv->dccpor_ndp);
114 break;
115 case DCCPO_ACK_VECTOR_0:
116 if (len > DCCP_MAX_ACK_VECTOR_LEN)
117 goto out_invalid_option;
118
119 if (pkt_type == DCCP_PKT_DATA)
120 continue;
121
122 opt_recv->dccpor_ack_vector_len = len;
123 opt_recv->dccpor_ack_vector_idx = value - options;
124
125 dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n",
126 debug_prefix, len,
127 (unsigned long long)
128 DCCP_SKB_CB(skb)->dccpd_ack_seq);
129 dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq,
130 value, len);
131 dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts,
132 sk,
133 DCCP_SKB_CB(skb)->dccpd_ack_seq,
134 len, value);
135 break;
136 case DCCPO_TIMESTAMP:
137 if (len != 4)
138 goto out_invalid_option;
139
140 opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
141
142 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
143 dccp_timestamp(sk, &dp->dccps_timestamp_time);
144
145 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
146 debug_prefix, opt_recv->dccpor_timestamp,
147 (unsigned long long)
148 DCCP_SKB_CB(skb)->dccpd_ack_seq);
149 break;
150 case DCCPO_TIMESTAMP_ECHO:
151 if (len != 4 && len != 6 && len != 8)
152 goto out_invalid_option;
153
154 opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
155
156 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
157 debug_prefix,
158 opt_recv->dccpor_timestamp_echo,
159 len + 2,
160 (unsigned long long)
161 DCCP_SKB_CB(skb)->dccpd_ack_seq);
162
163
164 if (len == 4)
165 break;
166
167 if (len == 6)
168 elapsed_time = ntohs(*(u16 *)(value + 4));
169 else
170 elapsed_time = ntohl(*(u32 *)(value + 4));
171
172 /* Give precedence to the biggest ELAPSED_TIME */
173 if (elapsed_time > opt_recv->dccpor_elapsed_time)
174 opt_recv->dccpor_elapsed_time = elapsed_time;
175 break;
176 case DCCPO_ELAPSED_TIME:
177 if (len != 2 && len != 4)
178 goto out_invalid_option;
179
180 if (pkt_type == DCCP_PKT_DATA)
181 continue;
182
183 if (len == 2)
184 elapsed_time = ntohs(*(u16 *)value);
185 else
186 elapsed_time = ntohl(*(u32 *)value);
187
188 if (elapsed_time > opt_recv->dccpor_elapsed_time)
189 opt_recv->dccpor_elapsed_time = elapsed_time;
190
191 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
192 elapsed_time);
193 break;
194 /*
195 * From draft-ietf-dccp-spec-11.txt:
196 *
197 * Option numbers 128 through 191 are for
198 * options sent from the HC-Sender to the
199 * HC-Receiver; option numbers 192 through 255
200 * are for options sent from the HC-Receiver to
201 * the HC-Sender.
202 */
203 case 128 ... 191: {
204 const u16 idx = value - options;
205
206 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
207 opt, len, idx,
208 value) != 0)
209 goto out_invalid_option;
210 }
211 break;
212 case 192 ... 255: {
213 const u16 idx = value - options;
214
215 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
216 opt, len, idx,
217 value) != 0)
218 goto out_invalid_option;
219 }
220 break;
221 default:
222 pr_info("DCCP(%p): option %d(len=%d) not "
223 "implemented, ignoring\n",
224 sk, opt, len);
225 break;
226 }
227 }
228
229 return 0;
230
231out_invalid_option:
232 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
233 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
234 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
235 return -1;
236}
237
238static void dccp_encode_value_var(const u32 value, unsigned char *to,
239 const unsigned int len)
240{
241 if (len > 3)
242 *to++ = (value & 0xFF000000) >> 24;
243 if (len > 2)
244 *to++ = (value & 0xFF0000) >> 16;
245 if (len > 1)
246 *to++ = (value & 0xFF00) >> 8;
247 if (len > 0)
248 *to++ = (value & 0xFF);
249}
250
251static inline int dccp_ndp_len(const int ndp)
252{
253 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
254}
255
256void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
257 const unsigned char option,
258 const void *value, const unsigned char len)
259{
260 unsigned char *to;
261
262 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
263 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
264 "%d option!\n", option);
265 return;
266 }
267
268 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
269
270 to = skb_push(skb, len + 2);
271 *to++ = option;
272 *to++ = len + 2;
273
274 memcpy(to, value, len);
275}
276
277EXPORT_SYMBOL_GPL(dccp_insert_option);
278
279static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
280{
281 struct dccp_sock *dp = dccp_sk(sk);
282 int ndp = dp->dccps_ndp_count;
283
284 if (dccp_non_data_packet(skb))
285 ++dp->dccps_ndp_count;
286 else
287 dp->dccps_ndp_count = 0;
288
289 if (ndp > 0) {
290 unsigned char *ptr;
291 const int ndp_len = dccp_ndp_len(ndp);
292 const int len = ndp_len + 2;
293
294 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
295 return;
296
297 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
298
299 ptr = skb_push(skb, len);
300 *ptr++ = DCCPO_NDP_COUNT;
301 *ptr++ = len;
302 dccp_encode_value_var(ndp, ptr, ndp_len);
303 }
304}
305
306static inline int dccp_elapsed_time_len(const u32 elapsed_time)
307{
308 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
309}
310
311void dccp_insert_option_elapsed_time(struct sock *sk,
312 struct sk_buff *skb,
313 u32 elapsed_time)
314{
315#ifdef CONFIG_IP_DCCP_DEBUG
316 struct dccp_sock *dp = dccp_sk(sk);
317 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
318 "CLIENT TX opt: " : "server TX opt: ";
319#endif
320 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
321 const int len = 2 + elapsed_time_len;
322 unsigned char *to;
323
324 if (elapsed_time_len == 0)
325 return;
326
327 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
328 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
329 "insert elapsed time!\n");
330 return;
331 }
332
333 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
334
335 to = skb_push(skb, len);
336 *to++ = DCCPO_ELAPSED_TIME;
337 *to++ = len;
338
339 if (elapsed_time_len == 2) {
340 const u16 var16 = htons((u16)elapsed_time);
341 memcpy(to, &var16, 2);
342 } else {
343 const u32 var32 = htonl(elapsed_time);
344 memcpy(to, &var32, 4);
345 }
346
347 dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
348 debug_prefix, elapsed_time,
349 len,
350 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
351}
352
353EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
354
355static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
356{
357 struct dccp_sock *dp = dccp_sk(sk);
358#ifdef CONFIG_IP_DCCP_DEBUG
359 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
360 "CLIENT TX opt: " : "server TX opt: ";
361#endif
362 struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
363 int len = ap->dccpap_buf_vector_len + 2;
364 struct timeval now;
365 u32 elapsed_time;
366 unsigned char *to, *from;
367
368 dccp_timestamp(sk, &now);
369 elapsed_time = timeval_delta(&now, &ap->dccpap_time) / 10;
370
371 if (elapsed_time != 0)
372 dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
373
374 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
375 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
376 "insert ACK Vector!\n");
377 return;
378 }
379
380 /*
381 * XXX: now we have just one ack vector sent record, so
382 * we have to wait for it to be cleared.
383 *
384 * Of course this is not acceptable, but this is just for
385 * basic testing now.
386 */
387 if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
388 return;
389
390 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
391
392 to = skb_push(skb, len);
393 *to++ = DCCPO_ACK_VECTOR_0;
394 *to++ = len;
395
396 len = ap->dccpap_buf_vector_len;
397 from = ap->dccpap_buf + ap->dccpap_buf_head;
398
399 /* Check if buf_head wraps */
400 if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
401 const unsigned int tailsize = (ap->dccpap_buf_len -
402 ap->dccpap_buf_head);
403
404 memcpy(to, from, tailsize);
405 to += tailsize;
406 len -= tailsize;
407 from = ap->dccpap_buf;
408 }
409
410 memcpy(to, from, len);
411 /*
412 * From draft-ietf-dccp-spec-11.txt:
413 *
414 * For each acknowledgement it sends, the HC-Receiver will add an
415 * acknowledgement record. ack_seqno will equal the HC-Receiver
416 * sequence number it used for the ack packet; ack_ptr will equal
417 * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
418 * equal buf_nonce.
419 *
420 * This implemention uses just one ack record for now.
421 */
422 ap->dccpap_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
423 ap->dccpap_ack_ptr = ap->dccpap_buf_head;
424 ap->dccpap_ack_ackno = ap->dccpap_buf_ackno;
425 ap->dccpap_ack_nonce = ap->dccpap_buf_nonce;
426 ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
427
428 dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
429 "ack_ackno=%llu\n",
430 debug_prefix, ap->dccpap_ack_vector_len,
431 (unsigned long long) ap->dccpap_ack_seqno,
432 (unsigned long long) ap->dccpap_ack_ackno);
433}
434
435void dccp_timestamp(const struct sock *sk, struct timeval *tv)
436{
437 const struct dccp_sock *dp = dccp_sk(sk);
438
439 do_gettimeofday(tv);
440 tv->tv_sec -= dp->dccps_epoch.tv_sec;
441 tv->tv_usec -= dp->dccps_epoch.tv_usec;
442
443 while (tv->tv_usec < 0) {
444 tv->tv_sec--;
445 tv->tv_usec += USEC_PER_SEC;
446 }
447}
448
449EXPORT_SYMBOL_GPL(dccp_timestamp);
450
451void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
452{
453 struct timeval tv;
454 u32 now;
455
456 dccp_timestamp(sk, &tv);
457 now = timeval_usecs(&tv) / 10;
458 /* yes this will overflow but that is the point as we want a
459 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
460
461 now = htonl(now);
462 dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
463}
464
465EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
466
467static void dccp_insert_option_timestamp_echo(struct sock *sk,
468 struct sk_buff *skb)
469{
470 struct dccp_sock *dp = dccp_sk(sk);
471#ifdef CONFIG_IP_DCCP_DEBUG
472 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
473 "CLIENT TX opt: " : "server TX opt: ";
474#endif
475 struct timeval now;
476 u32 tstamp_echo;
477 u32 elapsed_time;
478 int len, elapsed_time_len;
479 unsigned char *to;
480
481 dccp_timestamp(sk, &now);
482 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
483 elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
484 len = 6 + elapsed_time_len;
485
486 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
487 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
488 "timestamp echo!\n");
489 return;
490 }
491
492 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
493
494 to = skb_push(skb, len);
495 *to++ = DCCPO_TIMESTAMP_ECHO;
496 *to++ = len;
497
498 tstamp_echo = htonl(dp->dccps_timestamp_echo);
499 memcpy(to, &tstamp_echo, 4);
500 to += 4;
501
502 if (elapsed_time_len == 2) {
503 const u16 var16 = htons((u16)elapsed_time);
504 memcpy(to, &var16, 2);
505 } else if (elapsed_time_len == 4) {
506 const u32 var32 = htonl(elapsed_time);
507 memcpy(to, &var32, 4);
508 }
509
510 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
511 debug_prefix, dp->dccps_timestamp_echo,
512 len,
513 (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
514
515 dp->dccps_timestamp_echo = 0;
516 dp->dccps_timestamp_time.tv_sec = 0;
517 dp->dccps_timestamp_time.tv_usec = 0;
518}
519
520void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
521{
522 struct dccp_sock *dp = dccp_sk(sk);
523
524 DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
525
526 if (dp->dccps_options.dccpo_send_ndp_count)
527 dccp_insert_option_ndp(sk, skb);
528
529 if (!dccp_packet_without_ack(skb)) {
530 if (dp->dccps_options.dccpo_send_ack_vector &&
531 (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
532 DCCP_MAX_SEQNO + 1))
533 dccp_insert_option_ack_vector(sk, skb);
534 if (dp->dccps_timestamp_echo != 0)
535 dccp_insert_option_timestamp_echo(sk, skb);
536 }
537
538 if (dp->dccps_hc_rx_insert_options) {
539 ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
540 dp->dccps_hc_rx_insert_options = 0;
541 }
542 if (dp->dccps_hc_tx_insert_options) {
543 ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
544 dp->dccps_hc_tx_insert_options = 0;
545 }
546
547 /* XXX: insert other options when appropriate */
548
549 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
550 /* The length of all options has to be a multiple of 4 */
551 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
552
553 if (padding != 0) {
554 padding = 4 - padding;
555 memset(skb_push(skb, padding), 0, padding);
556 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
557 }
558 }
559}
560
561struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
562 const unsigned int __nocast priority)
563{
564 struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
565
566 if (ap != NULL) {
567#ifdef CONFIG_IP_DCCP_DEBUG
568 memset(ap->dccpap_buf, 0xFF, len);
569#endif
570 ap->dccpap_buf_len = len;
571 ap->dccpap_buf_head =
572 ap->dccpap_buf_tail =
573 ap->dccpap_buf_len - 1;
574 ap->dccpap_buf_ackno =
575 ap->dccpap_ack_ackno =
576 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
577 ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
578 ap->dccpap_ack_ptr = 0;
579 ap->dccpap_time.tv_sec = 0;
580 ap->dccpap_time.tv_usec = 0;
581 ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
582 }
583
584 return ap;
585}
586
587void dccp_ackpkts_free(struct dccp_ackpkts *ap)
588{
589 if (ap != NULL) {
590#ifdef CONFIG_IP_DCCP_DEBUG
591 memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
592#endif
593 kfree(ap);
594 }
595}
596
597static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
598 const unsigned int index)
599{
600 return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
601}
602
603static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
604 const unsigned int index)
605{
606 return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
607}
608
609/*
610 * If several packets are missing, the HC-Receiver may prefer to enter multiple
611 * bytes with run length 0, rather than a single byte with a larger run length;
612 * this simplifies table updates if one of the missing packets arrives.
613 */
614static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
615 const unsigned int packets,
616 const unsigned char state)
617{
618 unsigned int gap;
619 signed long new_head;
620
621 if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
622 return -ENOBUFS;
623
624 gap = packets - 1;
625 new_head = ap->dccpap_buf_head - packets;
626
627 if (new_head < 0) {
628 if (gap > 0) {
629 memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
630 gap + new_head + 1);
631 gap = -new_head;
632 }
633 new_head += ap->dccpap_buf_len;
634 }
635
636 ap->dccpap_buf_head = new_head;
637
638 if (gap > 0)
639 memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
640 DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
641
642 ap->dccpap_buf[ap->dccpap_buf_head] = state;
643 ap->dccpap_buf_vector_len += packets;
644 return 0;
645}
646
647/*
648 * Implements the draft-ietf-dccp-spec-11.txt Appendix A
649 */
650int dccp_ackpkts_add(struct dccp_ackpkts *ap, const struct sock *sk,
651 u64 ackno, u8 state)
652{
653 /*
654 * Check at the right places if the buffer is full, if it is, tell the
655 * caller to start dropping packets till the HC-Sender acks our ACK
656 * vectors, when we will free up space in dccpap_buf.
657 *
658 * We may well decide to do buffer compression, etc, but for now lets
659 * just drop.
660 *
661 * From Appendix A:
662 *
663 * Of course, the circular buffer may overflow, either when the
664 * HC-Sender is sending data at a very high rate, when the
665 * HC-Receiver's acknowledgements are not reaching the HC-Sender,
666 * or when the HC-Sender is forgetting to acknowledge those acks
667 * (so the HC-Receiver is unable to clean up old state). In this
668 * case, the HC-Receiver should either compress the buffer (by
669 * increasing run lengths when possible), transfer its state to
670 * a larger buffer, or, as a last resort, drop all received
671 * packets, without processing them whatsoever, until its buffer
672 * shrinks again.
673 */
674
675 /* See if this is the first ackno being inserted */
676 if (ap->dccpap_buf_vector_len == 0) {
677 ap->dccpap_buf[ap->dccpap_buf_head] = state;
678 ap->dccpap_buf_vector_len = 1;
679 } else if (after48(ackno, ap->dccpap_buf_ackno)) {
680 const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
681 ackno);
682
683 /*
684 * Look if the state of this packet is the same as the
685 * previous ackno and if so if we can bump the head len.
686 */
687 if (delta == 1 &&
688 dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
689 (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
690 DCCP_ACKPKTS_LEN_MASK))
691 ap->dccpap_buf[ap->dccpap_buf_head]++;
692 else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
693 return -ENOBUFS;
694 } else {
695 /*
696 * A.1.2. Old Packets
697 *
698 * When a packet with Sequence Number S arrives, and
699 * S <= buf_ackno, the HC-Receiver will scan the table
700 * for the byte corresponding to S. (Indexing structures
701 * could reduce the complexity of this scan.)
702 */
703 u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
704 unsigned int index = ap->dccpap_buf_head;
705
706 while (1) {
707 const u8 len = dccp_ackpkts_len(ap, index);
708 const u8 state = dccp_ackpkts_state(ap, index);
709 /*
710 * valid packets not yet in dccpap_buf have a reserved
711 * entry, with a len equal to 0.
712 */
713 if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
714 len == 0 && delta == 0) { /* Found our
715 reserved seat! */
716 dccp_pr_debug("Found %llu reserved seat!\n",
717 (unsigned long long) ackno);
718 ap->dccpap_buf[index] = state;
719 goto out;
720 }
721 /* len == 0 means one packet */
722 if (delta < len + 1)
723 goto out_duplicate;
724
725 delta -= len + 1;
726 if (++index == ap->dccpap_buf_len)
727 index = 0;
728 }
729 }
730
731 ap->dccpap_buf_ackno = ackno;
732 dccp_timestamp(sk, &ap->dccpap_time);
733out:
734 dccp_pr_debug("");
735 dccp_ackpkts_print(ap);
736 return 0;
737
738out_duplicate:
739 /* Duplicate packet */
740 dccp_pr_debug("Received a dup or already considered lost "
741 "packet: %llu\n", (unsigned long long) ackno);
742 return -EILSEQ;
743}
744
745#ifdef CONFIG_IP_DCCP_DEBUG
746void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
747 int len)
748{
749 if (!dccp_debug)
750 return;
751
752 printk("ACK vector len=%d, ackno=%llu |", len,
753 (unsigned long long) ackno);
754
755 while (len--) {
756 const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
757 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
758
759 printk("%d,%d|", state, rl);
760 ++vector;
761 }
762
763 printk("\n");
764}
765
766void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
767{
768 dccp_ackvector_print(ap->dccpap_buf_ackno,
769 ap->dccpap_buf + ap->dccpap_buf_head,
770 ap->dccpap_buf_vector_len);
771}
772#endif
773
774static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
775{
776 /*
777 * As we're keeping track of the ack vector size
778 * (dccpap_buf_vector_len) and the sent ack vector size
779 * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
780 * keep this code here as in the future we'll implement a vector of
781 * ack records, as suggested in draft-ietf-dccp-spec-11.txt
782 * Appendix A. -acme
783 */
784#if 0
785 ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
786 if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
787 ap->dccpap_buf_tail -= ap->dccpap_buf_len;
788#endif
789 ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
790}
791
792void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
793 u64 ackno)
794{
795 /* Check if we actually sent an ACK vector */
796 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
797 return;
798
799 if (ackno == ap->dccpap_ack_seqno) {
800#ifdef CONFIG_IP_DCCP_DEBUG
801 struct dccp_sock *dp = dccp_sk(sk);
802 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
803 "CLIENT rx ack: " : "server rx ack: ";
804#endif
805 dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
806 "ack_ackno=%llu, ACKED!\n",
807 debug_prefix, 1,
808 (unsigned long long) ap->dccpap_ack_seqno,
809 (unsigned long long) ap->dccpap_ack_ackno);
810 dccp_ackpkts_trow_away_ack_record(ap);
811 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
812 }
813}
814
815static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
816 struct sock *sk, u64 ackno,
817 const unsigned char len,
818 const unsigned char *vector)
819{
820 unsigned char i;
821
822 /* Check if we actually sent an ACK vector */
823 if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
824 return;
825 /*
826 * We're in the receiver half connection, so if the received an ACK
827 * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
828 * not interested.
829 *
830 * Extra explanation with example:
831 *
832 * if we received an ACK vector with ackno 50, it can only be acking
833 * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
834 */
835 /* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
836 if (before48(ackno, ap->dccpap_ack_seqno)) {
837 /* dccp_pr_debug_cat("yes\n"); */
838 return;
839 }
840 /* dccp_pr_debug_cat("no\n"); */
841
842 i = len;
843 while (i--) {
844 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
845 u64 ackno_end_rl;
846
847 dccp_set_seqno(&ackno_end_rl, ackno - rl);
848
849 /*
850 * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
851 * ap->dccpap_ack_seqno, ackno);
852 */
853 if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
854 const u8 state = (*vector &
855 DCCP_ACKPKTS_STATE_MASK) >> 6;
856 /* dccp_pr_debug_cat("yes\n"); */
857
858 if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
859#ifdef CONFIG_IP_DCCP_DEBUG
860 struct dccp_sock *dp = dccp_sk(sk);
861 const char *debug_prefix =
862 dp->dccps_role == DCCP_ROLE_CLIENT ?
863 "CLIENT rx ack: " : "server rx ack: ";
864#endif
865 dccp_pr_debug("%sACK vector 0, len=%d, "
866 "ack_seqno=%llu, ack_ackno=%llu, "
867 "ACKED!\n",
868 debug_prefix, len,
869 (unsigned long long)
870 ap->dccpap_ack_seqno,
871 (unsigned long long)
872 ap->dccpap_ack_ackno);
873 dccp_ackpkts_trow_away_ack_record(ap);
874 }
875 /*
876 * If dccpap_ack_seqno was not received, no problem
877 * we'll send another ACK vector.
878 */
879 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
880 break;
881 }
882 /* dccp_pr_debug_cat("no\n"); */
883
884 dccp_set_seqno(&ackno, ackno_end_rl - 1);
885 ++vector;
886 }
887}
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