[DCCP]: Miscellaneous code tidy-ups
[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 EXPORT_SYMBOL_GPL(sysctl_dccp_feat_sequence_window);
33
34 void dccp_minisock_init(struct dccp_minisock *dmsk)
35 {
36         dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
37         dmsk->dccpms_rx_ccid         = sysctl_dccp_feat_rx_ccid;
38         dmsk->dccpms_tx_ccid         = sysctl_dccp_feat_tx_ccid;
39         dmsk->dccpms_ack_ratio       = sysctl_dccp_feat_ack_ratio;
40         dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
41         dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
42 }
43
44 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
45 {
46         u32 value = 0;
47
48         if (len > 3)
49                 value += *bf++ << 24;
50         if (len > 2)
51                 value += *bf++ << 16;
52         if (len > 1)
53                 value += *bf++ << 8;
54         if (len > 0)
55                 value += *bf;
56
57         return value;
58 }
59
60 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
61 {
62         struct dccp_sock *dp = dccp_sk(sk);
63         const struct dccp_hdr *dh = dccp_hdr(skb);
64         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
65         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
66         unsigned char *opt_ptr = options;
67         const unsigned char *opt_end = (unsigned char *)dh +
68                                         (dh->dccph_doff * 4);
69         struct dccp_options_received *opt_recv = &dp->dccps_options_received;
70         unsigned char opt, len;
71         unsigned char *value;
72         u32 elapsed_time;
73         int rc;
74         int mandatory = 0;
75
76         memset(opt_recv, 0, sizeof(*opt_recv));
77
78         opt = len = 0;
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_MANDATORY:
108                         if (mandatory)
109                                 goto out_invalid_option;
110                         if (pkt_type != DCCP_PKT_DATA)
111                                 mandatory = 1;
112                         break;
113                 case DCCPO_NDP_COUNT:
114                         if (len > 3)
115                                 goto out_invalid_option;
116
117                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
118                         dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
119                                       opt_recv->dccpor_ndp);
120                         break;
121                 case DCCPO_CHANGE_L:
122                         /* fall through */
123                 case DCCPO_CHANGE_R:
124                         if (len < 2)
125                                 goto out_invalid_option;
126                         rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
127                                                    len - 1);
128                         /*
129                          * When there is a change error, change_recv is
130                          * responsible for dealing with it.  i.e. reply with an
131                          * empty confirm.
132                          * If the change was mandatory, then we need to die.
133                          */
134                         if (rc && mandatory)
135                                 goto out_invalid_option;
136                         break;
137                 case DCCPO_CONFIRM_L:
138                         /* fall through */
139                 case DCCPO_CONFIRM_R:
140                         if (len < 2)
141                                 goto out_invalid_option;
142                         if (dccp_feat_confirm_recv(sk, opt, *value,
143                                                    value + 1, len - 1))
144                                 goto out_invalid_option;
145                         break;
146                 case DCCPO_ACK_VECTOR_0:
147                 case DCCPO_ACK_VECTOR_1:
148                         if (pkt_type == DCCP_PKT_DATA)
149                                 break;
150
151                         if (dccp_msk(sk)->dccpms_send_ack_vector &&
152                             dccp_ackvec_parse(sk, skb, opt, value, len))
153                                 goto out_invalid_option;
154                         break;
155                 case DCCPO_TIMESTAMP:
156                         if (len != 4)
157                                 goto out_invalid_option;
158
159                         opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
160
161                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
162                         dccp_timestamp(sk, &dp->dccps_timestamp_time);
163
164                         dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
165                                       dccp_role(sk), opt_recv->dccpor_timestamp,
166                                       (unsigned long long)
167                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
168                         break;
169                 case DCCPO_TIMESTAMP_ECHO:
170                         if (len != 4 && len != 6 && len != 8)
171                                 goto out_invalid_option;
172
173                         opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
174
175                         dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
176                                       "ackno=%llu, ",  dccp_role(sk),
177                                       opt_recv->dccpor_timestamp_echo,
178                                       len + 2,
179                                       (unsigned long long)
180                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
181
182
183                         if (len == 4)
184                                 break;
185
186                         if (len == 6)
187                                 elapsed_time = ntohs(*(__be16 *)(value + 4));
188                         else
189                                 elapsed_time = ntohl(*(__be32 *)(value + 4));
190
191                         /* Give precedence to the biggest ELAPSED_TIME */
192                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
193                                 opt_recv->dccpor_elapsed_time = elapsed_time;
194                         break;
195                 case DCCPO_ELAPSED_TIME:
196                         if (len != 2 && len != 4)
197                                 goto out_invalid_option;
198
199                         if (pkt_type == DCCP_PKT_DATA)
200                                 continue;
201
202                         if (len == 2)
203                                 elapsed_time = ntohs(*(__be16 *)value);
204                         else
205                                 elapsed_time = ntohl(*(__be32 *)value);
206
207                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
208                                 opt_recv->dccpor_elapsed_time = elapsed_time;
209
210                         dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
211                                       dccp_role(sk), elapsed_time);
212                         break;
213                         /*
214                          * From RFC 4340, sec. 10.3:
215                          *
216                          *      Option numbers 128 through 191 are for
217                          *      options sent from the HC-Sender to the
218                          *      HC-Receiver; option numbers 192 through 255
219                          *      are for options sent from the HC-Receiver to
220                          *      the HC-Sender.
221                          */
222                 case 128 ... 191: {
223                         const u16 idx = value - options;
224
225                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
226                                                      opt, len, idx,
227                                                      value) != 0)
228                                 goto out_invalid_option;
229                 }
230                         break;
231                 case 192 ... 255: {
232                         const u16 idx = value - options;
233
234                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
235                                                      opt, len, idx,
236                                                      value) != 0)
237                                 goto out_invalid_option;
238                 }
239                         break;
240                 default:
241                         pr_info("DCCP(%p): option %d(len=%d) not "
242                                 "implemented, ignoring\n",
243                                 sk, opt, len);
244                         break;
245                 }
246
247                 if (opt != DCCPO_MANDATORY)
248                         mandatory = 0;
249         }
250
251         /* mandatory was the last byte in option list -> reset connection */
252         if (mandatory)
253                 goto out_invalid_option;
254
255         return 0;
256
257 out_invalid_option:
258         DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
259         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
260         pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
261         return -1;
262 }
263
264 EXPORT_SYMBOL_GPL(dccp_parse_options);
265
266 static void dccp_encode_value_var(const u32 value, unsigned char *to,
267                                   const unsigned int len)
268 {
269         if (len > 3)
270                 *to++ = (value & 0xFF000000) >> 24;
271         if (len > 2)
272                 *to++ = (value & 0xFF0000) >> 16;
273         if (len > 1)
274                 *to++ = (value & 0xFF00) >> 8;
275         if (len > 0)
276                 *to++ = (value & 0xFF);
277 }
278
279 static inline int dccp_ndp_len(const int ndp)
280 {
281         return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
282 }
283
284 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
285                         const unsigned char option,
286                         const void *value, const unsigned char len)
287 {
288         unsigned char *to;
289
290         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
291                 return -1;
292
293         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
294
295         to    = skb_push(skb, len + 2);
296         *to++ = option;
297         *to++ = len + 2;
298
299         memcpy(to, value, len);
300         return 0;
301 }
302
303 EXPORT_SYMBOL_GPL(dccp_insert_option);
304
305 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
306 {
307         struct dccp_sock *dp = dccp_sk(sk);
308         int ndp = dp->dccps_ndp_count;
309
310         if (dccp_non_data_packet(skb))
311                 ++dp->dccps_ndp_count;
312         else
313                 dp->dccps_ndp_count = 0;
314
315         if (ndp > 0) {
316                 unsigned char *ptr;
317                 const int ndp_len = dccp_ndp_len(ndp);
318                 const int len = ndp_len + 2;
319
320                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
321                         return -1;
322
323                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
324
325                 ptr = skb_push(skb, len);
326                 *ptr++ = DCCPO_NDP_COUNT;
327                 *ptr++ = len;
328                 dccp_encode_value_var(ndp, ptr, ndp_len);
329         }
330
331         return 0;
332 }
333
334 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
335 {
336         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
337 }
338
339 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
340                                     u32 elapsed_time)
341 {
342         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
343         const int len = 2 + elapsed_time_len;
344         unsigned char *to;
345
346         if (elapsed_time_len == 0)
347                 return 0;
348
349         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
350                 return -1;
351
352         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
353
354         to    = skb_push(skb, len);
355         *to++ = DCCPO_ELAPSED_TIME;
356         *to++ = len;
357
358         if (elapsed_time_len == 2) {
359                 const __be16 var16 = htons((u16)elapsed_time);
360                 memcpy(to, &var16, 2);
361         } else {
362                 const __be32 var32 = htonl(elapsed_time);
363                 memcpy(to, &var32, 4);
364         }
365
366         return 0;
367 }
368
369 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
370
371 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
372 {
373         const struct dccp_sock *dp = dccp_sk(sk);
374
375         do_gettimeofday(tv);
376         tv->tv_sec  -= dp->dccps_epoch.tv_sec;
377         tv->tv_usec -= dp->dccps_epoch.tv_usec;
378
379         while (tv->tv_usec < 0) {
380                 tv->tv_sec--;
381                 tv->tv_usec += USEC_PER_SEC;
382         }
383 }
384
385 EXPORT_SYMBOL_GPL(dccp_timestamp);
386
387 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
388 {
389         struct timeval tv;
390         __be32 now;
391
392         dccp_timestamp(sk, &tv);
393         now = htonl(timeval_usecs(&tv) / 10);
394         /* yes this will overflow but that is the point as we want a
395          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
396
397         return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
398 }
399
400 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
401
402 static int dccp_insert_option_timestamp_echo(struct sock *sk,
403                                              struct sk_buff *skb)
404 {
405         struct dccp_sock *dp = dccp_sk(sk);
406         struct timeval now;
407         __be32 tstamp_echo;
408         u32 elapsed_time;
409         int len, elapsed_time_len;
410         unsigned char *to;
411
412         dccp_timestamp(sk, &now);
413         elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
414         elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
415         len = 6 + elapsed_time_len;
416
417         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
418                 return -1;
419
420         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
421
422         to    = skb_push(skb, len);
423         *to++ = DCCPO_TIMESTAMP_ECHO;
424         *to++ = len;
425
426         tstamp_echo = htonl(dp->dccps_timestamp_echo);
427         memcpy(to, &tstamp_echo, 4);
428         to += 4;
429
430         if (elapsed_time_len == 2) {
431                 const __be16 var16 = htons((u16)elapsed_time);
432                 memcpy(to, &var16, 2);
433         } else if (elapsed_time_len == 4) {
434                 const __be32 var32 = htonl(elapsed_time);
435                 memcpy(to, &var32, 4);
436         }
437
438         dp->dccps_timestamp_echo = 0;
439         dp->dccps_timestamp_time.tv_sec = 0;
440         dp->dccps_timestamp_time.tv_usec = 0;
441         return 0;
442 }
443
444 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
445                                 u8 *val, u8 len)
446 {
447         u8 *to;
448
449         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
450                 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small"
451                                " to insert feature %d option!\n", feat);
452                 return -1;
453         }
454
455         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
456
457         to    = skb_push(skb, len + 3);
458         *to++ = type;
459         *to++ = len + 3;
460         *to++ = feat;
461
462         if (len)
463                 memcpy(to, val, len);
464
465         dccp_pr_debug("%s(%s (%d), ...), length %d\n",
466                       dccp_feat_typename(type),
467                       dccp_feat_name(feat), feat, len);
468         return 0;
469 }
470
471 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
472 {
473         struct dccp_sock *dp = dccp_sk(sk);
474         struct dccp_minisock *dmsk = dccp_msk(sk);
475         struct dccp_opt_pend *opt, *next;
476         int change = 0;
477
478         /* confirm any options [NN opts] */
479         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
480                 dccp_insert_feat_opt(skb, opt->dccpop_type,
481                                      opt->dccpop_feat, opt->dccpop_val,
482                                      opt->dccpop_len);
483                 /* fear empty confirms */
484                 if (opt->dccpop_val)
485                         kfree(opt->dccpop_val);
486                 kfree(opt);
487         }
488         INIT_LIST_HEAD(&dmsk->dccpms_conf);
489
490         /* see which features we need to send */
491         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
492                 /* see if we need to send any confirm */
493                 if (opt->dccpop_sc) {
494                         dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
495                                              opt->dccpop_feat,
496                                              opt->dccpop_sc->dccpoc_val,
497                                              opt->dccpop_sc->dccpoc_len);
498
499                         BUG_ON(!opt->dccpop_sc->dccpoc_val);
500                         kfree(opt->dccpop_sc->dccpoc_val);
501                         kfree(opt->dccpop_sc);
502                         opt->dccpop_sc = NULL;
503                 }
504
505                 /* any option not confirmed, re-send it */
506                 if (!opt->dccpop_conf) {
507                         dccp_insert_feat_opt(skb, opt->dccpop_type,
508                                              opt->dccpop_feat, opt->dccpop_val,
509                                              opt->dccpop_len);
510                         change++;
511                 }
512         }
513
514         /* Retransmit timer.
515          * If this is the master listening sock, we don't set a timer on it.  It
516          * should be fine because if the dude doesn't receive our RESPONSE
517          * [which will contain the CHANGE] he will send another REQUEST which
518          * will "retrnasmit" the change.
519          */
520         if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
521                 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
522
523                 /* XXX don't reset the timer on re-transmissions.  I.e. reset it
524                  * only when sending new stuff i guess.  Currently the timer
525                  * never backs off because on re-transmission it just resets it!
526                  */
527                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
528                                           inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
529         }
530
531         return 0;
532 }
533
534 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
535 {
536         struct dccp_sock *dp = dccp_sk(sk);
537         struct dccp_minisock *dmsk = dccp_msk(sk);
538
539         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
540
541         if (dmsk->dccpms_send_ndp_count &&
542             dccp_insert_option_ndp(sk, skb))
543                 return -1;
544
545         if (!dccp_packet_without_ack(skb)) {
546                 if (dmsk->dccpms_send_ack_vector &&
547                     dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
548                     dccp_insert_option_ackvec(sk, skb))
549                         return -1;
550
551                 if (dp->dccps_timestamp_echo != 0 &&
552                     dccp_insert_option_timestamp_echo(sk, skb))
553                         return -1;
554         }
555
556         if (dp->dccps_hc_rx_insert_options) {
557                 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
558                         return -1;
559                 dp->dccps_hc_rx_insert_options = 0;
560         }
561         if (dp->dccps_hc_tx_insert_options) {
562                 if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb))
563                         return -1;
564                 dp->dccps_hc_tx_insert_options = 0;
565         }
566
567         /* Feature negotiation */
568         /* Data packets can't do feat negotiation */
569         if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
570             DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
571             dccp_insert_options_feat(sk, skb))
572                 return -1;
573
574         /* XXX: insert other options when appropriate */
575
576         if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
577                 /* The length of all options has to be a multiple of 4 */
578                 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
579
580                 if (padding != 0) {
581                         padding = 4 - padding;
582                         memset(skb_push(skb, padding), 0, padding);
583                         DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
584                 }
585         }
586
587         return 0;
588 }