[PATCH] Fix CONFIG_ACPI_BLACKLIST_YEAR
[sfrench/cifs-2.6.git] / net / dccp / options.c
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
24 static 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 */
31 static 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
38 void dccp_options_init(struct dccp_options *dccpo)
39 {
40         memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
41 }
42
43 static 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
59 int 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
76         memset(opt_recv, 0, sizeof(*opt_recv));
77
78         while (opt_ptr != opt_end) {
79                 opt   = *opt_ptr++;
80                 len   = 0;
81                 value = NULL;
82
83                 /* Check if this isn't a single byte option */
84                 if (opt > DCCPO_MAX_RESERVED) {
85                         if (opt_ptr == opt_end)
86                                 goto out_invalid_option;
87
88                         len = *opt_ptr++;
89                         if (len < 3)
90                                 goto out_invalid_option;
91                         /*
92                          * Remove the type and len fields, leaving
93                          * just the value size
94                          */
95                         len     -= 2;
96                         value   = opt_ptr;
97                         opt_ptr += len;
98
99                         if (opt_ptr > opt_end)
100                                 goto out_invalid_option;
101                 }
102
103                 switch (opt) {
104                 case DCCPO_PADDING:
105                         break;
106                 case DCCPO_NDP_COUNT:
107                         if (len > 3)
108                                 goto out_invalid_option;
109
110                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
111                         dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
112                                       opt_recv->dccpor_ndp);
113                         break;
114                 case DCCPO_ACK_VECTOR_0:
115                         if (len > DCCP_MAX_ACK_VECTOR_LEN)
116                                 goto out_invalid_option;
117
118                         if (pkt_type == DCCP_PKT_DATA)
119                                 continue;
120
121                         opt_recv->dccpor_ack_vector_len = len;
122                         opt_recv->dccpor_ack_vector_idx = value - options;
123
124                         dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n",
125                                       debug_prefix, len,
126                                       (unsigned long long)
127                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
128                         dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq,
129                                              value, len);
130                         dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts,
131                                                          sk,
132                                                  DCCP_SKB_CB(skb)->dccpd_ack_seq,
133                                                          len, value);
134                         break;
135                 case DCCPO_TIMESTAMP:
136                         if (len != 4)
137                                 goto out_invalid_option;
138
139                         opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
140
141                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
142                         do_gettimeofday(&dp->dccps_timestamp_time);
143
144                         dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
145                                       debug_prefix, opt_recv->dccpor_timestamp,
146                                       (unsigned long long)
147                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
148                         break;
149                 case DCCPO_TIMESTAMP_ECHO:
150                         if (len != 4 && len != 6 && len != 8)
151                                 goto out_invalid_option;
152
153                         opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
154
155                         dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
156                                       debug_prefix,
157                                       opt_recv->dccpor_timestamp_echo,
158                                       len + 2,
159                                       (unsigned long long)
160                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
161
162                         if (len > 4) {
163                                 if (len == 6)
164                                         opt_recv->dccpor_elapsed_time =
165                                                  ntohs(*(u16 *)(value + 4));
166                                 else
167                                         opt_recv->dccpor_elapsed_time =
168                                                  ntohl(*(u32 *)(value + 4));
169
170                                 dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n",
171                                       debug_prefix,
172                                       opt_recv->dccpor_elapsed_time);
173                         }
174                         break;
175                 case DCCPO_ELAPSED_TIME:
176                         if (len != 2 && len != 4)
177                                 goto out_invalid_option;
178
179                         if (pkt_type == DCCP_PKT_DATA)
180                                 continue;
181
182                         if (len == 2)
183                                 opt_recv->dccpor_elapsed_time =
184                                                         ntohs(*(u16 *)value);
185                         else
186                                 opt_recv->dccpor_elapsed_time =
187                                                         ntohl(*(u32 *)value);
188
189                         dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
190                                       opt_recv->dccpor_elapsed_time);
191                         break;
192                         /*
193                          * From draft-ietf-dccp-spec-11.txt:
194                          *
195                          *      Option numbers 128 through 191 are for
196                          *      options sent from the HC-Sender to the
197                          *      HC-Receiver; option numbers 192 through 255
198                          *      are for options sent from the HC-Receiver to
199                          *      the HC-Sender.
200                          */
201                 case 128 ... 191: {
202                         const u16 idx = value - options;
203
204                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
205                                                      opt, len, idx,
206                                                      value) != 0)
207                                 goto out_invalid_option;
208                 }
209                         break;
210                 case 192 ... 255: {
211                         const u16 idx = value - options;
212
213                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
214                                                      opt, len, idx,
215                                                      value) != 0)
216                                 goto out_invalid_option;
217                 }
218                         break;
219                 default:
220                         pr_info("DCCP(%p): option %d(len=%d) not "
221                                 "implemented, ignoring\n",
222                                 sk, opt, len);
223                         break;
224                 }
225         }
226
227         return 0;
228
229 out_invalid_option:
230         DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
231         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
232         pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
233         return -1;
234 }
235
236 static void dccp_encode_value_var(const u32 value, unsigned char *to,
237                                   const unsigned int len)
238 {
239         if (len > 3)
240                 *to++ = (value & 0xFF000000) >> 24;
241         if (len > 2)
242                 *to++ = (value & 0xFF0000) >> 16;
243         if (len > 1)
244                 *to++ = (value & 0xFF00) >> 8;
245         if (len > 0)
246                 *to++ = (value & 0xFF);
247 }
248
249 static inline int dccp_ndp_len(const int ndp)
250 {
251         return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
252 }
253
254 void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
255                         const unsigned char option,
256                         const void *value, const unsigned char len)
257 {
258         unsigned char *to;
259
260         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
261                 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
262                                "%d option!\n", option);
263                 return;
264         }
265
266         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
267
268         to    = skb_push(skb, len + 2);
269         *to++ = option;
270         *to++ = len + 2;
271
272         memcpy(to, value, len);
273 }
274
275 EXPORT_SYMBOL_GPL(dccp_insert_option);
276
277 static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
278 {
279         struct dccp_sock *dp = dccp_sk(sk);
280         int ndp = dp->dccps_ndp_count;
281
282         if (dccp_non_data_packet(skb))
283                 ++dp->dccps_ndp_count;
284         else
285                 dp->dccps_ndp_count = 0;
286
287         if (ndp > 0) {
288                 unsigned char *ptr;
289                 const int ndp_len = dccp_ndp_len(ndp);
290                 const int len = ndp_len + 2;
291
292                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
293                         return;
294
295                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
296
297                 ptr = skb_push(skb, len);
298                 *ptr++ = DCCPO_NDP_COUNT;
299                 *ptr++ = len;
300                 dccp_encode_value_var(ndp, ptr, ndp_len);
301         }
302 }
303
304 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
305 {
306         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
307 }
308
309 void dccp_insert_option_elapsed_time(struct sock *sk,
310                                      struct sk_buff *skb,
311                                      u32 elapsed_time)
312 {
313 #ifdef CONFIG_IP_DCCP_DEBUG
314         struct dccp_sock *dp = dccp_sk(sk);
315         const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
316                                         "CLIENT TX opt: " : "server TX opt: ";
317 #endif
318         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
319         const int len = 2 + elapsed_time_len;
320         unsigned char *to;
321
322         if (elapsed_time_len == 0)
323                 return;
324
325         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
326                 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
327                                          "insert elapsed time!\n");
328                 return;
329         }
330
331         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
332
333         to    = skb_push(skb, len);
334         *to++ = DCCPO_ELAPSED_TIME;
335         *to++ = len;
336
337         if (elapsed_time_len == 2) {
338                 const u16 var16 = htons((u16)elapsed_time);
339                 memcpy(to, &var16, 2);
340         } else {
341                 const u32 var32 = htonl(elapsed_time);
342                 memcpy(to, &var32, 4);
343         }
344
345         dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
346                       debug_prefix, elapsed_time,
347                       len,
348                       (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
349 }
350
351 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
352
353 static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
354 {
355         struct dccp_sock *dp = dccp_sk(sk);
356 #ifdef CONFIG_IP_DCCP_DEBUG
357         const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
358                                         "CLIENT TX opt: " : "server TX opt: ";
359 #endif
360         struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
361         int len = ap->dccpap_buf_vector_len + 2;
362         const u32 elapsed_time = timeval_now_delta(&ap->dccpap_time) / 10;
363         unsigned char *to, *from;
364
365         if (elapsed_time != 0)
366                 dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
367
368         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
369                 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
370                                          "insert ACK Vector!\n");
371                 return;
372         }
373
374         /*
375          * XXX: now we have just one ack vector sent record, so
376          * we have to wait for it to be cleared.
377          *
378          * Of course this is not acceptable, but this is just for
379          * basic testing now.
380          */
381         if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
382                 return;
383
384         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
385
386         to    = skb_push(skb, len);
387         *to++ = DCCPO_ACK_VECTOR_0;
388         *to++ = len;
389
390         len  = ap->dccpap_buf_vector_len;
391         from = ap->dccpap_buf + ap->dccpap_buf_head;
392
393         /* Check if buf_head wraps */
394         if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
395                 const unsigned int tailsize = (ap->dccpap_buf_len -
396                                                ap->dccpap_buf_head);
397
398                 memcpy(to, from, tailsize);
399                 to   += tailsize;
400                 len  -= tailsize;
401                 from = ap->dccpap_buf;
402         }
403
404         memcpy(to, from, len);
405         /*
406          *      From draft-ietf-dccp-spec-11.txt:
407          *
408          *      For each acknowledgement it sends, the HC-Receiver will add an
409          *      acknowledgement record.  ack_seqno will equal the HC-Receiver
410          *      sequence number it used for the ack packet; ack_ptr will equal
411          *      buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
412          *      equal buf_nonce.
413          *
414          * This implemention uses just one ack record for now.
415          */
416         ap->dccpap_ack_seqno      = DCCP_SKB_CB(skb)->dccpd_seq;
417         ap->dccpap_ack_ptr        = ap->dccpap_buf_head;
418         ap->dccpap_ack_ackno      = ap->dccpap_buf_ackno;
419         ap->dccpap_ack_nonce      = ap->dccpap_buf_nonce;
420         ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
421
422         dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
423                       "ack_ackno=%llu\n",
424                       debug_prefix, ap->dccpap_ack_vector_len,
425                       (unsigned long long) ap->dccpap_ack_seqno,
426                       (unsigned long long) ap->dccpap_ack_ackno);
427 }
428
429 void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
430 {
431         struct timeval tv;
432         u32 now;
433         
434         do_gettimeofday(&tv);
435         now = (tv.tv_sec * USEC_PER_SEC + tv.tv_usec) / 10;
436         /* yes this will overflow but that is the point as we want a
437          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
438
439         now = htonl(now);
440         dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
441 }
442
443 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
444
445 static void dccp_insert_option_timestamp_echo(struct sock *sk,
446                                               struct sk_buff *skb)
447 {
448         struct dccp_sock *dp = dccp_sk(sk);
449 #ifdef CONFIG_IP_DCCP_DEBUG
450         const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
451                                         "CLIENT TX opt: " : "server TX opt: ";
452 #endif
453         u32 tstamp_echo;
454         const u32 elapsed_time =
455                         timeval_now_delta(&dp->dccps_timestamp_time) / 10;
456         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
457         const int len = 6 + elapsed_time_len;
458         unsigned char *to;
459
460         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
461                 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
462                                          "timestamp echo!\n");
463                 return;
464         }
465
466         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
467
468         to    = skb_push(skb, len);
469         *to++ = DCCPO_TIMESTAMP_ECHO;
470         *to++ = len;
471
472         tstamp_echo = htonl(dp->dccps_timestamp_echo);
473         memcpy(to, &tstamp_echo, 4);
474         to += 4;
475         
476         if (elapsed_time_len == 2) {
477                 const u16 var16 = htons((u16)elapsed_time);
478                 memcpy(to, &var16, 2);
479         } else if (elapsed_time_len == 4) {
480                 const u32 var32 = htonl(elapsed_time);
481                 memcpy(to, &var32, 4);
482         }
483
484         dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
485                       debug_prefix, dp->dccps_timestamp_echo,
486                       len,
487                       (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
488
489         dp->dccps_timestamp_echo = 0;
490         dp->dccps_timestamp_time.tv_sec = 0;
491         dp->dccps_timestamp_time.tv_usec = 0;
492 }
493
494 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
495 {
496         struct dccp_sock *dp = dccp_sk(sk);
497
498         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
499
500         if (dp->dccps_options.dccpo_send_ndp_count)
501                 dccp_insert_option_ndp(sk, skb);
502
503         if (!dccp_packet_without_ack(skb)) {
504                 if (dp->dccps_options.dccpo_send_ack_vector &&
505                     (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
506                      DCCP_MAX_SEQNO + 1))
507                         dccp_insert_option_ack_vector(sk, skb);
508
509                 if (dp->dccps_timestamp_echo != 0)
510                         dccp_insert_option_timestamp_echo(sk, skb);
511         }
512
513         ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
514         ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
515
516         /* XXX: insert other options when appropriate */
517
518         if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
519                 /* The length of all options has to be a multiple of 4 */
520                 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
521
522                 if (padding != 0) {
523                         padding = 4 - padding;
524                         memset(skb_push(skb, padding), 0, padding);
525                         DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
526                 }
527         }
528 }
529
530 struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
531                                         const unsigned int __nocast priority)
532 {
533         struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
534
535         if (ap != NULL) {
536 #ifdef CONFIG_IP_DCCP_DEBUG
537                 memset(ap->dccpap_buf, 0xFF, len);
538 #endif
539                 ap->dccpap_buf_len   = len;
540                 ap->dccpap_buf_head  =
541                         ap->dccpap_buf_tail =
542                                 ap->dccpap_buf_len - 1;
543                 ap->dccpap_buf_ackno =
544                         ap->dccpap_ack_ackno =
545                                 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
546                 ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
547                 ap->dccpap_ack_ptr   = 0;
548                 ap->dccpap_time.tv_sec = 0;
549                 ap->dccpap_time.tv_usec = 0;
550                 ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
551         }
552
553         return ap;
554 }
555
556 void dccp_ackpkts_free(struct dccp_ackpkts *ap)
557 {
558         if (ap != NULL) {
559 #ifdef CONFIG_IP_DCCP_DEBUG
560                 memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
561 #endif
562                 kfree(ap);
563         }
564 }
565
566 static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
567                                     const unsigned int index)
568 {
569         return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
570 }
571
572 static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
573                                   const unsigned int index)
574 {
575         return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
576 }
577
578 /*
579  * If several packets are missing, the HC-Receiver may prefer to enter multiple
580  * bytes with run length 0, rather than a single byte with a larger run length;
581  * this simplifies table updates if one of the missing packets arrives.
582  */
583 static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
584                                                   const unsigned int packets,
585                                                   const unsigned char state)
586 {
587         unsigned int gap;
588         signed long new_head;
589
590         if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
591                 return -ENOBUFS;
592
593         gap      = packets - 1;
594         new_head = ap->dccpap_buf_head - packets;
595
596         if (new_head < 0) {
597                 if (gap > 0) {
598                         memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
599                                gap + new_head + 1);
600                         gap = -new_head;
601                 }
602                 new_head += ap->dccpap_buf_len;
603         } 
604
605         ap->dccpap_buf_head = new_head;
606
607         if (gap > 0)
608                 memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
609                        DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
610
611         ap->dccpap_buf[ap->dccpap_buf_head] = state;
612         ap->dccpap_buf_vector_len += packets;
613         return 0;
614 }
615
616 /*
617  * Implements the draft-ietf-dccp-spec-11.txt Appendix A
618  */
619 int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state)
620 {
621         /*
622          * Check at the right places if the buffer is full, if it is, tell the
623          * caller to start dropping packets till the HC-Sender acks our ACK
624          * vectors, when we will free up space in dccpap_buf.
625          *
626          * We may well decide to do buffer compression, etc, but for now lets
627          * just drop.
628          *
629          * From Appendix A:
630          *
631          *      Of course, the circular buffer may overflow, either when the
632          *      HC-Sender is sending data at a very high rate, when the
633          *      HC-Receiver's acknowledgements are not reaching the HC-Sender,
634          *      or when the HC-Sender is forgetting to acknowledge those acks
635          *      (so the HC-Receiver is unable to clean up old state). In this
636          *      case, the HC-Receiver should either compress the buffer (by
637          *      increasing run lengths when possible), transfer its state to
638          *      a larger buffer, or, as a last resort, drop all received
639          *      packets, without processing them whatsoever, until its buffer
640          *      shrinks again.
641          */
642
643         /* See if this is the first ackno being inserted */
644         if (ap->dccpap_buf_vector_len == 0) {
645                 ap->dccpap_buf[ap->dccpap_buf_head] = state;
646                 ap->dccpap_buf_vector_len = 1;
647         } else if (after48(ackno, ap->dccpap_buf_ackno)) {
648                 const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
649                                                    ackno);
650
651                 /*
652                  * Look if the state of this packet is the same as the
653                  * previous ackno and if so if we can bump the head len.
654                  */
655                 if (delta == 1 &&
656                     dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
657                     (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
658                      DCCP_ACKPKTS_LEN_MASK))
659                         ap->dccpap_buf[ap->dccpap_buf_head]++;
660                 else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
661                         return -ENOBUFS;
662         } else {
663                 /*
664                  * A.1.2.  Old Packets
665                  *
666                  *      When a packet with Sequence Number S arrives, and
667                  *      S <= buf_ackno, the HC-Receiver will scan the table
668                  *      for the byte corresponding to S. (Indexing structures
669                  *      could reduce the complexity of this scan.)
670                  */
671                 u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
672                 unsigned int index = ap->dccpap_buf_head;
673
674                 while (1) {
675                         const u8 len = dccp_ackpkts_len(ap, index);
676                         const u8 state = dccp_ackpkts_state(ap, index);
677                         /*
678                          * valid packets not yet in dccpap_buf have a reserved
679                          * entry, with a len equal to 0.
680                          */
681                         if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
682                             len == 0 && delta == 0) { /* Found our
683                                                          reserved seat! */
684                                 dccp_pr_debug("Found %llu reserved seat!\n",
685                                               (unsigned long long) ackno);
686                                 ap->dccpap_buf[index] = state;
687                                 goto out;
688                         }
689                         /* len == 0 means one packet */
690                         if (delta < len + 1)
691                                 goto out_duplicate;
692
693                         delta -= len + 1;
694                         if (++index == ap->dccpap_buf_len)
695                                 index = 0;
696                 }
697         }
698
699         ap->dccpap_buf_ackno = ackno;
700         do_gettimeofday(&ap->dccpap_time);
701 out:
702         dccp_pr_debug("");
703         dccp_ackpkts_print(ap);
704         return 0;
705
706 out_duplicate:
707         /* Duplicate packet */
708         dccp_pr_debug("Received a dup or already considered lost "
709                       "packet: %llu\n", (unsigned long long) ackno);
710         return -EILSEQ;
711 }
712
713 #ifdef CONFIG_IP_DCCP_DEBUG
714 void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
715                           int len)
716 {
717         if (!dccp_debug)
718                 return;
719
720         printk("ACK vector len=%d, ackno=%llu |", len,
721                (unsigned long long) ackno);
722
723         while (len--) {
724                 const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
725                 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
726
727                 printk("%d,%d|", state, rl);
728                 ++vector;
729         }
730
731         printk("\n");
732 }
733
734 void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
735 {
736         dccp_ackvector_print(ap->dccpap_buf_ackno,
737                              ap->dccpap_buf + ap->dccpap_buf_head,
738                              ap->dccpap_buf_vector_len);
739 }
740 #endif
741
742 static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
743 {
744         /*
745          * As we're keeping track of the ack vector size
746          * (dccpap_buf_vector_len) and the sent ack vector size
747          * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
748          * keep this code here as in the future we'll implement a vector of
749          * ack records, as suggested in draft-ietf-dccp-spec-11.txt
750          * Appendix A. -acme
751          */
752 #if 0
753         ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
754         if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
755                 ap->dccpap_buf_tail -= ap->dccpap_buf_len;
756 #endif
757         ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
758 }
759
760 void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
761                                  u64 ackno)
762 {
763         /* Check if we actually sent an ACK vector */
764         if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
765                 return;
766
767         if (ackno == ap->dccpap_ack_seqno) {
768 #ifdef CONFIG_IP_DCCP_DEBUG
769                 struct dccp_sock *dp = dccp_sk(sk);
770                 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
771                                         "CLIENT rx ack: " : "server rx ack: ";
772 #endif
773                 dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
774                               "ack_ackno=%llu, ACKED!\n",
775                               debug_prefix, 1,
776                               (unsigned long long) ap->dccpap_ack_seqno,
777                               (unsigned long long) ap->dccpap_ack_ackno);
778                 dccp_ackpkts_trow_away_ack_record(ap);
779                 ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
780         }
781 }
782
783 static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
784                                              struct sock *sk, u64 ackno,
785                                              const unsigned char len,
786                                              const unsigned char *vector)
787 {
788         unsigned char i;
789
790         /* Check if we actually sent an ACK vector */
791         if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
792                 return;
793         /*
794          * We're in the receiver half connection, so if the received an ACK
795          * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
796          * not interested.
797          *
798          * Extra explanation with example:
799          * 
800          * if we received an ACK vector with ackno 50, it can only be acking
801          * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
802          */
803         /* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
804         if (before48(ackno, ap->dccpap_ack_seqno)) {
805                 /* dccp_pr_debug_cat("yes\n"); */
806                 return;
807         }
808         /* dccp_pr_debug_cat("no\n"); */
809
810         i = len;
811         while (i--) {
812                 const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
813                 u64 ackno_end_rl;
814
815                 dccp_set_seqno(&ackno_end_rl, ackno - rl);
816
817                 /*
818                  * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
819                  * ap->dccpap_ack_seqno, ackno);
820                  */
821                 if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
822                         const u8 state = (*vector &
823                                           DCCP_ACKPKTS_STATE_MASK) >> 6;
824                         /* dccp_pr_debug_cat("yes\n"); */
825
826                         if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
827 #ifdef CONFIG_IP_DCCP_DEBUG
828                                 struct dccp_sock *dp = dccp_sk(sk);
829                                 const char *debug_prefix =
830                                         dp->dccps_role == DCCP_ROLE_CLIENT ?
831                                         "CLIENT rx ack: " : "server rx ack: ";
832 #endif
833                                 dccp_pr_debug("%sACK vector 0, len=%d, "
834                                               "ack_seqno=%llu, ack_ackno=%llu, "
835                                               "ACKED!\n",
836                                               debug_prefix, len,
837                                               (unsigned long long)
838                                               ap->dccpap_ack_seqno,
839                                               (unsigned long long)
840                                               ap->dccpap_ack_ackno);
841                                 dccp_ackpkts_trow_away_ack_record(ap);
842                         }
843                         /*
844                          * If dccpap_ack_seqno was not received, no problem
845                          * we'll send another ACK vector.
846                          */
847                         ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
848                         break;
849                 }
850                 /* dccp_pr_debug_cat("no\n"); */
851
852                 dccp_set_seqno(&ackno, ackno_end_rl - 1);
853                 ++vector;
854         }
855 }