[TCP/DCCP/RANDOM]: Remove unused exports.
[linux-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 <ian.mcdonald@jandi.co.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/dccp.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/skbuff.h>
19
20 #include "ackvec.h"
21 #include "ccid.h"
22 #include "dccp.h"
23 #include "feat.h"
24
25 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
26 int sysctl_dccp_feat_rx_ccid          = DCCPF_INITIAL_CCID;
27 int sysctl_dccp_feat_tx_ccid          = DCCPF_INITIAL_CCID;
28 int sysctl_dccp_feat_ack_ratio        = DCCPF_INITIAL_ACK_RATIO;
29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
30 int sysctl_dccp_feat_send_ndp_count  = DCCPF_INITIAL_SEND_NDP_COUNT;
31
32 void dccp_minisock_init(struct dccp_minisock *dmsk)
33 {
34         dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
35         dmsk->dccpms_rx_ccid         = sysctl_dccp_feat_rx_ccid;
36         dmsk->dccpms_tx_ccid         = sysctl_dccp_feat_tx_ccid;
37         dmsk->dccpms_ack_ratio       = sysctl_dccp_feat_ack_ratio;
38         dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
39         dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
40 }
41
42 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
43 {
44         u32 value = 0;
45
46         if (len > 3)
47                 value += *bf++ << 24;
48         if (len > 2)
49                 value += *bf++ << 16;
50         if (len > 1)
51                 value += *bf++ << 8;
52         if (len > 0)
53                 value += *bf;
54
55         return value;
56 }
57
58 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
59 {
60         struct dccp_sock *dp = dccp_sk(sk);
61         const struct dccp_hdr *dh = dccp_hdr(skb);
62         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
63         u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
64         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
65         unsigned char *opt_ptr = options;
66         const unsigned char *opt_end = (unsigned char *)dh +
67                                         (dh->dccph_doff * 4);
68         struct dccp_options_received *opt_recv = &dp->dccps_options_received;
69         unsigned char opt, len;
70         unsigned char *value;
71         u32 elapsed_time;
72         int rc;
73         int mandatory = 0;
74
75         memset(opt_recv, 0, sizeof(*opt_recv));
76
77         opt = len = 0;
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_MANDATORY:
107                         if (mandatory)
108                                 goto out_invalid_option;
109                         if (pkt_type != DCCP_PKT_DATA)
110                                 mandatory = 1;
111                         break;
112                 case DCCPO_NDP_COUNT:
113                         if (len > 3)
114                                 goto out_invalid_option;
115
116                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
117                         dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
118                                       opt_recv->dccpor_ndp);
119                         break;
120                 case DCCPO_CHANGE_L:
121                         /* fall through */
122                 case DCCPO_CHANGE_R:
123                         if (len < 2)
124                                 goto out_invalid_option;
125                         rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
126                                                    len - 1);
127                         /*
128                          * When there is a change error, change_recv is
129                          * responsible for dealing with it.  i.e. reply with an
130                          * empty confirm.
131                          * If the change was mandatory, then we need to die.
132                          */
133                         if (rc && mandatory)
134                                 goto out_invalid_option;
135                         break;
136                 case DCCPO_CONFIRM_L:
137                         /* fall through */
138                 case DCCPO_CONFIRM_R:
139                         if (len < 2)
140                                 goto out_invalid_option;
141                         if (dccp_feat_confirm_recv(sk, opt, *value,
142                                                    value + 1, len - 1))
143                                 goto out_invalid_option;
144                         break;
145                 case DCCPO_ACK_VECTOR_0:
146                 case DCCPO_ACK_VECTOR_1:
147                         if (pkt_type == DCCP_PKT_DATA)
148                                 break;
149
150                         if (dccp_msk(sk)->dccpms_send_ack_vector &&
151                             dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
152                                 goto out_invalid_option;
153                         break;
154                 case DCCPO_TIMESTAMP:
155                         if (len != 4)
156                                 goto out_invalid_option;
157
158                         opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
159
160                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
161                         dccp_timestamp(sk, &dp->dccps_timestamp_time);
162
163                         dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
164                                       dccp_role(sk), opt_recv->dccpor_timestamp,
165                                       (unsigned long long)
166                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
167                         break;
168                 case DCCPO_TIMESTAMP_ECHO:
169                         if (len != 4 && len != 6 && len != 8)
170                                 goto out_invalid_option;
171
172                         opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
173
174                         dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
175                                       "ackno=%llu, ",  dccp_role(sk),
176                                       opt_recv->dccpor_timestamp_echo,
177                                       len + 2,
178                                       (unsigned long long)
179                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
180
181
182                         if (len == 4)
183                                 break;
184
185                         if (len == 6)
186                                 elapsed_time = ntohs(*(__be16 *)(value + 4));
187                         else
188                                 elapsed_time = ntohl(*(__be32 *)(value + 4));
189
190                         /* Give precedence to the biggest ELAPSED_TIME */
191                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
192                                 opt_recv->dccpor_elapsed_time = elapsed_time;
193                         break;
194                 case DCCPO_ELAPSED_TIME:
195                         if (len != 2 && len != 4)
196                                 goto out_invalid_option;
197
198                         if (pkt_type == DCCP_PKT_DATA)
199                                 continue;
200
201                         if (len == 2)
202                                 elapsed_time = ntohs(*(__be16 *)value);
203                         else
204                                 elapsed_time = ntohl(*(__be32 *)value);
205
206                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
207                                 opt_recv->dccpor_elapsed_time = elapsed_time;
208
209                         dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
210                                       dccp_role(sk), elapsed_time);
211                         break;
212                         /*
213                          * From RFC 4340, sec. 10.3:
214                          *
215                          *      Option numbers 128 through 191 are for
216                          *      options sent from the HC-Sender to the
217                          *      HC-Receiver; option numbers 192 through 255
218                          *      are for options sent from the HC-Receiver to
219                          *      the HC-Sender.
220                          */
221                 case 128 ... 191: {
222                         const u16 idx = value - options;
223
224                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
225                                                      opt, len, idx,
226                                                      value) != 0)
227                                 goto out_invalid_option;
228                 }
229                         break;
230                 case 192 ... 255: {
231                         const u16 idx = value - options;
232
233                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
234                                                      opt, len, idx,
235                                                      value) != 0)
236                                 goto out_invalid_option;
237                 }
238                         break;
239                 default:
240                         DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
241                                   "implemented, ignoring", sk, opt, len);
242                         break;
243                 }
244
245                 if (opt != DCCPO_MANDATORY)
246                         mandatory = 0;
247         }
248
249         /* mandatory was the last byte in option list -> reset connection */
250         if (mandatory)
251                 goto out_invalid_option;
252
253         return 0;
254
255 out_invalid_option:
256         DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
257         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
258         DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
259         return -1;
260 }
261
262 EXPORT_SYMBOL_GPL(dccp_parse_options);
263
264 static void dccp_encode_value_var(const u32 value, unsigned char *to,
265                                   const unsigned int len)
266 {
267         if (len > 3)
268                 *to++ = (value & 0xFF000000) >> 24;
269         if (len > 2)
270                 *to++ = (value & 0xFF0000) >> 16;
271         if (len > 1)
272                 *to++ = (value & 0xFF00) >> 8;
273         if (len > 0)
274                 *to++ = (value & 0xFF);
275 }
276
277 static inline int dccp_ndp_len(const int ndp)
278 {
279         return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
280 }
281
282 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
283                         const unsigned char option,
284                         const void *value, const unsigned char len)
285 {
286         unsigned char *to;
287
288         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
289                 return -1;
290
291         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
292
293         to    = skb_push(skb, len + 2);
294         *to++ = option;
295         *to++ = len + 2;
296
297         memcpy(to, value, len);
298         return 0;
299 }
300
301 EXPORT_SYMBOL_GPL(dccp_insert_option);
302
303 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
304 {
305         struct dccp_sock *dp = dccp_sk(sk);
306         int ndp = dp->dccps_ndp_count;
307
308         if (dccp_non_data_packet(skb))
309                 ++dp->dccps_ndp_count;
310         else
311                 dp->dccps_ndp_count = 0;
312
313         if (ndp > 0) {
314                 unsigned char *ptr;
315                 const int ndp_len = dccp_ndp_len(ndp);
316                 const int len = ndp_len + 2;
317
318                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
319                         return -1;
320
321                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
322
323                 ptr = skb_push(skb, len);
324                 *ptr++ = DCCPO_NDP_COUNT;
325                 *ptr++ = len;
326                 dccp_encode_value_var(ndp, ptr, ndp_len);
327         }
328
329         return 0;
330 }
331
332 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
333 {
334         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
335 }
336
337 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
338                                     u32 elapsed_time)
339 {
340         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
341         const int len = 2 + elapsed_time_len;
342         unsigned char *to;
343
344         if (elapsed_time_len == 0)
345                 return 0;
346
347         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
348                 return -1;
349
350         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
351
352         to    = skb_push(skb, len);
353         *to++ = DCCPO_ELAPSED_TIME;
354         *to++ = len;
355
356         if (elapsed_time_len == 2) {
357                 const __be16 var16 = htons((u16)elapsed_time);
358                 memcpy(to, &var16, 2);
359         } else {
360                 const __be32 var32 = htonl(elapsed_time);
361                 memcpy(to, &var32, 4);
362         }
363
364         return 0;
365 }
366
367 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
368
369 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
370 {
371         const struct dccp_sock *dp = dccp_sk(sk);
372
373         do_gettimeofday(tv);
374         tv->tv_sec  -= dp->dccps_epoch.tv_sec;
375         tv->tv_usec -= dp->dccps_epoch.tv_usec;
376
377         while (tv->tv_usec < 0) {
378                 tv->tv_sec--;
379                 tv->tv_usec += USEC_PER_SEC;
380         }
381 }
382
383 EXPORT_SYMBOL_GPL(dccp_timestamp);
384
385 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
386 {
387         struct timeval tv;
388         __be32 now;
389
390         dccp_timestamp(sk, &tv);
391         now = htonl(timeval_usecs(&tv) / 10);
392         /* yes this will overflow but that is the point as we want a
393          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
394
395         return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
396 }
397
398 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
399
400 static int dccp_insert_option_timestamp_echo(struct sock *sk,
401                                              struct sk_buff *skb)
402 {
403         struct dccp_sock *dp = dccp_sk(sk);
404         struct timeval now;
405         __be32 tstamp_echo;
406         u32 elapsed_time;
407         int len, elapsed_time_len;
408         unsigned char *to;
409
410         dccp_timestamp(sk, &now);
411         elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
412         elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
413         len = 6 + elapsed_time_len;
414
415         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
416                 return -1;
417
418         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
419
420         to    = skb_push(skb, len);
421         *to++ = DCCPO_TIMESTAMP_ECHO;
422         *to++ = len;
423
424         tstamp_echo = htonl(dp->dccps_timestamp_echo);
425         memcpy(to, &tstamp_echo, 4);
426         to += 4;
427
428         if (elapsed_time_len == 2) {
429                 const __be16 var16 = htons((u16)elapsed_time);
430                 memcpy(to, &var16, 2);
431         } else if (elapsed_time_len == 4) {
432                 const __be32 var32 = htonl(elapsed_time);
433                 memcpy(to, &var32, 4);
434         }
435
436         dp->dccps_timestamp_echo = 0;
437         dp->dccps_timestamp_time.tv_sec = 0;
438         dp->dccps_timestamp_time.tv_usec = 0;
439         return 0;
440 }
441
442 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
443                                 u8 *val, u8 len)
444 {
445         u8 *to;
446
447         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
448                 DCCP_WARN("packet too small for feature %d option!\n", feat);
449                 return -1;
450         }
451
452         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
453
454         to    = skb_push(skb, len + 3);
455         *to++ = type;
456         *to++ = len + 3;
457         *to++ = feat;
458
459         if (len)
460                 memcpy(to, val, len);
461
462         dccp_pr_debug("%s(%s (%d), ...), length %d\n",
463                       dccp_feat_typename(type),
464                       dccp_feat_name(feat), feat, len);
465         return 0;
466 }
467
468 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
469 {
470         struct dccp_sock *dp = dccp_sk(sk);
471         struct dccp_minisock *dmsk = dccp_msk(sk);
472         struct dccp_opt_pend *opt, *next;
473         int change = 0;
474
475         /* confirm any options [NN opts] */
476         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
477                 dccp_insert_feat_opt(skb, opt->dccpop_type,
478                                      opt->dccpop_feat, opt->dccpop_val,
479                                      opt->dccpop_len);
480                 /* fear empty confirms */
481                 if (opt->dccpop_val)
482                         kfree(opt->dccpop_val);
483                 kfree(opt);
484         }
485         INIT_LIST_HEAD(&dmsk->dccpms_conf);
486
487         /* see which features we need to send */
488         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
489                 /* see if we need to send any confirm */
490                 if (opt->dccpop_sc) {
491                         dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
492                                              opt->dccpop_feat,
493                                              opt->dccpop_sc->dccpoc_val,
494                                              opt->dccpop_sc->dccpoc_len);
495
496                         BUG_ON(!opt->dccpop_sc->dccpoc_val);
497                         kfree(opt->dccpop_sc->dccpoc_val);
498                         kfree(opt->dccpop_sc);
499                         opt->dccpop_sc = NULL;
500                 }
501
502                 /* any option not confirmed, re-send it */
503                 if (!opt->dccpop_conf) {
504                         dccp_insert_feat_opt(skb, opt->dccpop_type,
505                                              opt->dccpop_feat, opt->dccpop_val,
506                                              opt->dccpop_len);
507                         change++;
508                 }
509         }
510
511         /* Retransmit timer.
512          * If this is the master listening sock, we don't set a timer on it.  It
513          * should be fine because if the dude doesn't receive our RESPONSE
514          * [which will contain the CHANGE] he will send another REQUEST which
515          * will "retrnasmit" the change.
516          */
517         if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
518                 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
519
520                 /* XXX don't reset the timer on re-transmissions.  I.e. reset it
521                  * only when sending new stuff i guess.  Currently the timer
522                  * never backs off because on re-transmission it just resets it!
523                  */
524                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
525                                           inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
526         }
527
528         return 0;
529 }
530
531 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
532 {
533         struct dccp_sock *dp = dccp_sk(sk);
534         struct dccp_minisock *dmsk = dccp_msk(sk);
535
536         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
537
538         if (dmsk->dccpms_send_ndp_count &&
539             dccp_insert_option_ndp(sk, skb))
540                 return -1;
541
542         if (!dccp_packet_without_ack(skb)) {
543                 if (dmsk->dccpms_send_ack_vector &&
544                     dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
545                     dccp_insert_option_ackvec(sk, skb))
546                         return -1;
547
548                 if (dp->dccps_timestamp_echo != 0 &&
549                     dccp_insert_option_timestamp_echo(sk, skb))
550                         return -1;
551         }
552
553         if (dp->dccps_hc_rx_insert_options) {
554                 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
555                         return -1;
556                 dp->dccps_hc_rx_insert_options = 0;
557         }
558
559         /* Feature negotiation */
560         /* Data packets can't do feat negotiation */
561         if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
562             DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
563             dccp_insert_options_feat(sk, skb))
564                 return -1;
565
566         /* XXX: insert other options when appropriate */
567
568         if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
569                 /* The length of all options has to be a multiple of 4 */
570                 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
571
572                 if (padding != 0) {
573                         padding = 4 - padding;
574                         memset(skb_push(skb, padding), 0, padding);
575                         DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
576                 }
577         }
578
579         return 0;
580 }