net core: fix kernel-doc for new function parameters
[linux-2.6.git] / net / dccp / feat.c
1 /*
2  *  net/dccp/feat.c
3  *
4  *  An implementation of the DCCP protocol
5  *  Andrea Bittau <a.bittau@cs.ucl.ac.uk>
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License
9  *      as published by the Free Software Foundation; either version
10  *      2 of the License, or (at your option) any later version.
11  */
12
13 #include <linux/module.h>
14
15 #include "ccid.h"
16 #include "feat.h"
17
18 #define DCCP_FEAT_SP_NOAGREE (-123)
19
20 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
21                      u8 *val, u8 len, gfp_t gfp)
22 {
23         struct dccp_opt_pend *opt;
24
25         dccp_feat_debug(type, feature, *val);
26
27         if (!dccp_feat_is_valid_type(type)) {
28                 DCCP_WARN("option type %d invalid in negotiation\n", type);
29                 return 1;
30         }
31         if (!dccp_feat_is_valid_length(type, feature, len)) {
32                 DCCP_WARN("invalid length %d\n", len);
33                 return 1;
34         }
35         /* XXX add further sanity checks */
36
37         /* check if that feature is already being negotiated */
38         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
39                 /* ok we found a negotiation for this option already */
40                 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
41                         dccp_pr_debug("Replacing old\n");
42                         /* replace */
43                         BUG_ON(opt->dccpop_val == NULL);
44                         kfree(opt->dccpop_val);
45                         opt->dccpop_val  = val;
46                         opt->dccpop_len  = len;
47                         opt->dccpop_conf = 0;
48                         return 0;
49                 }
50         }
51
52         /* negotiation for a new feature */
53         opt = kmalloc(sizeof(*opt), gfp);
54         if (opt == NULL)
55                 return -ENOMEM;
56
57         opt->dccpop_type = type;
58         opt->dccpop_feat = feature;
59         opt->dccpop_len  = len;
60         opt->dccpop_val  = val;
61         opt->dccpop_conf = 0;
62         opt->dccpop_sc   = NULL;
63
64         BUG_ON(opt->dccpop_val == NULL);
65
66         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
67         return 0;
68 }
69
70 EXPORT_SYMBOL_GPL(dccp_feat_change);
71
72 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
73 {
74         struct dccp_sock *dp = dccp_sk(sk);
75         struct dccp_minisock *dmsk = dccp_msk(sk);
76         /* figure out if we are changing our CCID or the peer's */
77         const int rx = type == DCCPO_CHANGE_R;
78         const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
79         struct ccid *new_ccid;
80
81         /* Check if nothing is being changed. */
82         if (ccid_nr == new_ccid_nr)
83                 return 0;
84
85         new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
86         if (new_ccid == NULL)
87                 return -ENOMEM;
88
89         if (rx) {
90                 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
91                 dp->dccps_hc_rx_ccid = new_ccid;
92                 dmsk->dccpms_rx_ccid = new_ccid_nr;
93         } else {
94                 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
95                 dp->dccps_hc_tx_ccid = new_ccid;
96                 dmsk->dccpms_tx_ccid = new_ccid_nr;
97         }
98
99         return 0;
100 }
101
102 /* XXX taking only u8 vals */
103 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
104 {
105         dccp_feat_debug(type, feat, val);
106
107         switch (feat) {
108         case DCCPF_CCID:
109                 return dccp_feat_update_ccid(sk, type, val);
110         default:
111                 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
112                               dccp_feat_typename(type), feat);
113                 break;
114         }
115         return 0;
116 }
117
118 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
119                                u8 *rpref, u8 rlen)
120 {
121         struct dccp_sock *dp = dccp_sk(sk);
122         u8 *spref, slen, *res = NULL;
123         int i, j, rc, agree = 1;
124
125         BUG_ON(rpref == NULL);
126
127         /* check if we are the black sheep */
128         if (dp->dccps_role == DCCP_ROLE_CLIENT) {
129                 spref = rpref;
130                 slen  = rlen;
131                 rpref = opt->dccpop_val;
132                 rlen  = opt->dccpop_len;
133         } else {
134                 spref = opt->dccpop_val;
135                 slen  = opt->dccpop_len;
136         }
137         /*
138          * Now we have server preference list in spref and client preference in
139          * rpref
140          */
141         BUG_ON(spref == NULL);
142         BUG_ON(rpref == NULL);
143
144         /* FIXME sanity check vals */
145
146         /* Are values in any order?  XXX Lame "algorithm" here */
147         /* XXX assume values are 1 byte */
148         for (i = 0; i < slen; i++) {
149                 for (j = 0; j < rlen; j++) {
150                         if (spref[i] == rpref[j]) {
151                                 res = &spref[i];
152                                 break;
153                         }
154                 }
155                 if (res)
156                         break;
157         }
158
159         /* we didn't agree on anything */
160         if (res == NULL) {
161                 /* confirm previous value */
162                 switch (opt->dccpop_feat) {
163                 case DCCPF_CCID:
164                         /* XXX did i get this right? =P */
165                         if (opt->dccpop_type == DCCPO_CHANGE_L)
166                                 res = &dccp_msk(sk)->dccpms_tx_ccid;
167                         else
168                                 res = &dccp_msk(sk)->dccpms_rx_ccid;
169                         break;
170
171                 default:
172                         DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
173                         /* XXX implement res */
174                         return -EFAULT;
175                 }
176
177                 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
178                 agree = 0; /* this is used for mandatory options... */
179         }
180
181         /* need to put result and our preference list */
182         /* XXX assume 1 byte vals */
183         rlen = 1 + opt->dccpop_len;
184         rpref = kmalloc(rlen, GFP_ATOMIC);
185         if (rpref == NULL)
186                 return -ENOMEM;
187
188         *rpref = *res;
189         memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
190
191         /* put it in the "confirm queue" */
192         if (opt->dccpop_sc == NULL) {
193                 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
194                 if (opt->dccpop_sc == NULL) {
195                         kfree(rpref);
196                         return -ENOMEM;
197                 }
198         } else {
199                 /* recycle the confirm slot */
200                 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
201                 kfree(opt->dccpop_sc->dccpoc_val);
202                 dccp_pr_debug("recycling confirm slot\n");
203         }
204         memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
205
206         opt->dccpop_sc->dccpoc_val = rpref;
207         opt->dccpop_sc->dccpoc_len = rlen;
208
209         /* update the option on our side [we are about to send the confirm] */
210         rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
211         if (rc) {
212                 kfree(opt->dccpop_sc->dccpoc_val);
213                 kfree(opt->dccpop_sc);
214                 opt->dccpop_sc = NULL;
215                 return rc;
216         }
217
218         dccp_pr_debug("Will confirm %d\n", *rpref);
219
220         /* say we want to change to X but we just got a confirm X, suppress our
221          * change
222          */
223         if (!opt->dccpop_conf) {
224                 if (*opt->dccpop_val == *res)
225                         opt->dccpop_conf = 1;
226                 dccp_pr_debug("won't ask for change of same feature\n");
227         }
228
229         return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
230 }
231
232 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
233 {
234         struct dccp_minisock *dmsk = dccp_msk(sk);
235         struct dccp_opt_pend *opt;
236         int rc = 1;
237         u8 t;
238
239         /*
240          * We received a CHANGE.  We gotta match it against our own preference
241          * list.  If we got a CHANGE_R it means it's a change for us, so we need
242          * to compare our CHANGE_L list.
243          */
244         if (type == DCCPO_CHANGE_L)
245                 t = DCCPO_CHANGE_R;
246         else
247                 t = DCCPO_CHANGE_L;
248
249         /* find our preference list for this feature */
250         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
251                 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
252                         continue;
253
254                 /* find the winner from the two preference lists */
255                 rc = dccp_feat_reconcile(sk, opt, val, len);
256                 break;
257         }
258
259         /* We didn't deal with the change.  This can happen if we have no
260          * preference list for the feature.  In fact, it just shouldn't
261          * happen---if we understand a feature, we should have a preference list
262          * with at least the default value.
263          */
264         BUG_ON(rc == 1);
265
266         return rc;
267 }
268
269 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
270 {
271         struct dccp_opt_pend *opt;
272         struct dccp_minisock *dmsk = dccp_msk(sk);
273         u8 *copy;
274         int rc;
275
276         /* NN features must be Change L (sec. 6.3.2) */
277         if (type != DCCPO_CHANGE_L) {
278                 dccp_pr_debug("received %s for NN feature %d\n",
279                                 dccp_feat_typename(type), feature);
280                 return -EFAULT;
281         }
282
283         /* XXX sanity check opt val */
284
285         /* copy option so we can confirm it */
286         opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
287         if (opt == NULL)
288                 return -ENOMEM;
289
290         copy = kmemdup(val, len, GFP_ATOMIC);
291         if (copy == NULL) {
292                 kfree(opt);
293                 return -ENOMEM;
294         }
295
296         opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
297         opt->dccpop_feat = feature;
298         opt->dccpop_val  = copy;
299         opt->dccpop_len  = len;
300
301         /* change feature */
302         rc = dccp_feat_update(sk, type, feature, *val);
303         if (rc) {
304                 kfree(opt->dccpop_val);
305                 kfree(opt);
306                 return rc;
307         }
308
309         dccp_feat_debug(type, feature, *copy);
310
311         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
312
313         return 0;
314 }
315
316 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
317                                     u8 type, u8 feature)
318 {
319         /* XXX check if other confirms for that are queued and recycle slot */
320         struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
321
322         if (opt == NULL) {
323                 /* XXX what do we do?  Ignoring should be fine.  It's a change
324                  * after all =P
325                  */
326                 return;
327         }
328
329         switch (type) {
330         case DCCPO_CHANGE_L:
331                 opt->dccpop_type = DCCPO_CONFIRM_R;
332                 break;
333         case DCCPO_CHANGE_R:
334                 opt->dccpop_type = DCCPO_CONFIRM_L;
335                 break;
336         default:
337                 DCCP_WARN("invalid type %d\n", type);
338                 kfree(opt);
339                 return;
340         }
341         opt->dccpop_feat = feature;
342         opt->dccpop_val  = NULL;
343         opt->dccpop_len  = 0;
344
345         /* change feature */
346         dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
347
348         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
349 }
350
351 static void dccp_feat_flush_confirm(struct sock *sk)
352 {
353         struct dccp_minisock *dmsk = dccp_msk(sk);
354         /* Check if there is anything to confirm in the first place */
355         int yes = !list_empty(&dmsk->dccpms_conf);
356
357         if (!yes) {
358                 struct dccp_opt_pend *opt;
359
360                 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
361                         if (opt->dccpop_conf) {
362                                 yes = 1;
363                                 break;
364                         }
365                 }
366         }
367
368         if (!yes)
369                 return;
370
371         /* OK there is something to confirm... */
372         /* XXX check if packet is in flight?  Send delayed ack?? */
373         if (sk->sk_state == DCCP_OPEN)
374                 dccp_send_ack(sk);
375 }
376
377 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
378 {
379         int rc;
380
381         dccp_feat_debug(type, feature, *val);
382
383         /* figure out if it's SP or NN feature */
384         switch (feature) {
385         /* deal with SP features */
386         case DCCPF_CCID:
387                 rc = dccp_feat_sp(sk, type, feature, val, len);
388                 break;
389
390         /* deal with NN features */
391         case DCCPF_ACK_RATIO:
392                 rc = dccp_feat_nn(sk, type, feature, val, len);
393                 break;
394
395         /* XXX implement other features */
396         default:
397                 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
398                               dccp_feat_typename(type), feature);
399                 rc = -EFAULT;
400                 break;
401         }
402
403         /* check if there were problems changing features */
404         if (rc) {
405                 /* If we don't agree on SP, we sent a confirm for old value.
406                  * However we propagate rc to caller in case option was
407                  * mandatory
408                  */
409                 if (rc != DCCP_FEAT_SP_NOAGREE)
410                         dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
411         }
412
413         /* generate the confirm [if required] */
414         dccp_feat_flush_confirm(sk);
415
416         return rc;
417 }
418
419 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
420
421 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
422                            u8 *val, u8 len)
423 {
424         u8 t;
425         struct dccp_opt_pend *opt;
426         struct dccp_minisock *dmsk = dccp_msk(sk);
427         int found = 0;
428         int all_confirmed = 1;
429
430         dccp_feat_debug(type, feature, *val);
431
432         /* locate our change request */
433         switch (type) {
434         case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
435         case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
436         default:              DCCP_WARN("invalid type %d\n", type);
437                               return 1;
438
439         }
440         /* XXX sanity check feature value */
441
442         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
443                 if (!opt->dccpop_conf && opt->dccpop_type == t &&
444                     opt->dccpop_feat == feature) {
445                         found = 1;
446                         dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
447
448                         /* XXX do sanity check */
449
450                         opt->dccpop_conf = 1;
451
452                         /* We got a confirmation---change the option */
453                         dccp_feat_update(sk, opt->dccpop_type,
454                                          opt->dccpop_feat, *val);
455
456                         /* XXX check the return value of dccp_feat_update */
457                         break;
458                 }
459
460                 if (!opt->dccpop_conf)
461                         all_confirmed = 0;
462         }
463
464         /* fix re-transmit timer */
465         /* XXX gotta make sure that no option negotiation occurs during
466          * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
467          * on.  if all options are confirmed it might kill timer which should
468          * remain alive until close is received.
469          */
470         if (all_confirmed) {
471                 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
472                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
473         }
474
475         if (!found)
476                 dccp_pr_debug("%s(%d, ...) never requested\n",
477                               dccp_feat_typename(type), feature);
478         return 0;
479 }
480
481 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
482
483 void dccp_feat_clean(struct dccp_minisock *dmsk)
484 {
485         struct dccp_opt_pend *opt, *next;
486
487         list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
488                                  dccpop_node) {
489                 BUG_ON(opt->dccpop_val == NULL);
490                 kfree(opt->dccpop_val);
491
492                 if (opt->dccpop_sc != NULL) {
493                         BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
494                         kfree(opt->dccpop_sc->dccpoc_val);
495                         kfree(opt->dccpop_sc);
496                 }
497
498                 kfree(opt);
499         }
500         INIT_LIST_HEAD(&dmsk->dccpms_pending);
501
502         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
503                 BUG_ON(opt == NULL);
504                 if (opt->dccpop_val != NULL)
505                         kfree(opt->dccpop_val);
506                 kfree(opt);
507         }
508         INIT_LIST_HEAD(&dmsk->dccpms_conf);
509 }
510
511 EXPORT_SYMBOL_GPL(dccp_feat_clean);
512
513 /* this is to be called only when a listening sock creates its child.  It is
514  * assumed by the function---the confirm is not duplicated, but rather it is
515  * "passed on".
516  */
517 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
518 {
519         struct dccp_minisock *olddmsk = dccp_msk(oldsk);
520         struct dccp_minisock *newdmsk = dccp_msk(newsk);
521         struct dccp_opt_pend *opt;
522         int rc = 0;
523
524         INIT_LIST_HEAD(&newdmsk->dccpms_pending);
525         INIT_LIST_HEAD(&newdmsk->dccpms_conf);
526
527         list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
528                 struct dccp_opt_pend *newopt;
529                 /* copy the value of the option */
530                 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
531
532                 if (val == NULL)
533                         goto out_clean;
534
535                 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
536                 if (newopt == NULL) {
537                         kfree(val);
538                         goto out_clean;
539                 }
540
541                 /* insert the option */
542                 newopt->dccpop_val = val;
543                 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
544
545                 /* XXX what happens with backlogs and multiple connections at
546                  * once...
547                  */
548                 /* the master socket no longer needs to worry about confirms */
549                 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
550
551                 /* reset state for a new socket */
552                 opt->dccpop_conf = 0;
553         }
554
555         /* XXX not doing anything about the conf queue */
556
557 out:
558         return rc;
559
560 out_clean:
561         dccp_feat_clean(newdmsk);
562         rc = -ENOMEM;
563         goto out;
564 }
565
566 EXPORT_SYMBOL_GPL(dccp_feat_clone);
567
568 static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
569                             u8 *val, u8 len)
570 {
571         int rc = -ENOMEM;
572         u8 *copy = kmemdup(val, len, GFP_KERNEL);
573
574         if (copy != NULL) {
575                 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
576                 if (rc)
577                         kfree(copy);
578         }
579         return rc;
580 }
581
582 int dccp_feat_init(struct dccp_minisock *dmsk)
583 {
584         int rc;
585
586         INIT_LIST_HEAD(&dmsk->dccpms_pending);
587         INIT_LIST_HEAD(&dmsk->dccpms_conf);
588
589         /* CCID L */
590         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
591                               &dmsk->dccpms_tx_ccid, 1);
592         if (rc)
593                 goto out;
594
595         /* CCID R */
596         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
597                               &dmsk->dccpms_rx_ccid, 1);
598         if (rc)
599                 goto out;
600
601         /* Ack ratio */
602         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
603                               &dmsk->dccpms_ack_ratio, 1);
604 out:
605         return rc;
606 }
607
608 EXPORT_SYMBOL_GPL(dccp_feat_init);
609
610 #ifdef CONFIG_IP_DCCP_DEBUG
611 const char *dccp_feat_typename(const u8 type)
612 {
613         switch(type) {
614         case DCCPO_CHANGE_L:  return("ChangeL");
615         case DCCPO_CONFIRM_L: return("ConfirmL");
616         case DCCPO_CHANGE_R:  return("ChangeR");
617         case DCCPO_CONFIRM_R: return("ConfirmR");
618         /* the following case must not appear in feature negotation  */
619         default:              dccp_pr_debug("unknown type %d [BUG!]\n", type);
620         }
621         return NULL;
622 }
623
624 EXPORT_SYMBOL_GPL(dccp_feat_typename);
625
626 const char *dccp_feat_name(const u8 feat)
627 {
628         static const char *feature_names[] = {
629                 [DCCPF_RESERVED]        = "Reserved",
630                 [DCCPF_CCID]            = "CCID",
631                 [DCCPF_SHORT_SEQNOS]    = "Allow Short Seqnos",
632                 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
633                 [DCCPF_ECN_INCAPABLE]   = "ECN Incapable",
634                 [DCCPF_ACK_RATIO]       = "Ack Ratio",
635                 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
636                 [DCCPF_SEND_NDP_COUNT]  = "Send NDP Count",
637                 [DCCPF_MIN_CSUM_COVER]  = "Min. Csum Coverage",
638                 [DCCPF_DATA_CHECKSUM]   = "Send Data Checksum",
639         };
640         if (feat >= DCCPF_MIN_CCID_SPECIFIC)
641                 return "CCID-specific";
642
643         if (dccp_feat_is_reserved(feat))
644                 return feature_names[DCCPF_RESERVED];
645
646         return feature_names[feat];
647 }
648
649 EXPORT_SYMBOL_GPL(dccp_feat_name);
650 #endif /* CONFIG_IP_DCCP_DEBUG */