4 * An implementation of the DCCP protocol
5 * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
9 * o Feature negotiation is coordinated with connection setup (as in TCP), wild
10 * changes of parameters of an established connection are not supported.
11 * o All currently known SP features have 1-byte quantities. If in the future
12 * extensions of RFCs 4340..42 define features with item lengths larger than
13 * one byte, a feature-specific extension of the code will be required.
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
21 #include <linux/module.h>
26 #define DCCP_FEAT_SP_NOAGREE (-123)
29 u8 feat_num; /* DCCPF_xxx */
30 enum dccp_feat_type rxtx; /* RX or TX */
31 enum dccp_feat_type reconciliation; /* SP or NN */
32 u8 default_value; /* as in 6.4 */
34 * Lookup table for location and type of features (from RFC 4340/4342)
35 * +--------------------------+----+-----+----+----+---------+-----------+
36 * | Feature | Location | Reconc. | Initial | Section |
37 * | | RX | TX | SP | NN | Value | Reference |
38 * +--------------------------+----+-----+----+----+---------+-----------+
39 * | DCCPF_CCID | | X | X | | 2 | 10 |
40 * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 |
41 * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 |
42 * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 |
43 * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 |
44 * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 |
45 * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 |
46 * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 |
47 * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 |
48 * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 |
49 * +--------------------------+----+-----+----+----+---------+-----------+
51 } dccp_feat_table[] = {
52 { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2 },
53 { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0 },
54 { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
55 { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0 },
56 { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2 },
57 { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
58 { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0 },
59 { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0 },
60 { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0 },
61 { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0 },
63 #define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table)
66 * dccp_feat_index - Hash function to map feature number into array position
67 * Returns consecutive array index or -1 if the feature is not understood.
69 static int dccp_feat_index(u8 feat_num)
71 /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
72 if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)
76 * Other features: add cases for new feature types here after adding
77 * them to the above table.
80 case DCCPF_SEND_LEV_RATE:
81 return DCCP_FEAT_SUPPORTED_MAX - 1;
86 static u8 dccp_feat_type(u8 feat_num)
88 int idx = dccp_feat_index(feat_num);
92 return dccp_feat_table[idx].reconciliation;
95 static int dccp_feat_default_value(u8 feat_num)
97 int idx = dccp_feat_index(feat_num);
99 * There are no default values for unknown features, so encountering a
100 * negative index here indicates a serious problem somewhere else.
102 DCCP_BUG_ON(idx < 0);
104 return idx < 0 ? 0 : dccp_feat_table[idx].default_value;
107 /* copy constructor, fval must not already contain allocated memory */
108 static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
111 if (fval->sp.len > 0) {
112 fval->sp.vec = kmemdup(val, len, gfp_any());
113 if (fval->sp.vec == NULL) {
121 static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
123 if (unlikely(val == NULL))
125 if (dccp_feat_type(feat_num) == FEAT_SP)
127 memset(val, 0, sizeof(*val));
130 static struct dccp_feat_entry *
131 dccp_feat_clone_entry(struct dccp_feat_entry const *original)
133 struct dccp_feat_entry *new;
134 u8 type = dccp_feat_type(original->feat_num);
136 if (type == FEAT_UNKNOWN)
139 new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any());
143 if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val,
144 original->val.sp.vec,
145 original->val.sp.len)) {
152 static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
155 dccp_feat_val_destructor(entry->feat_num, &entry->val);
161 * List management functions
163 * Feature negotiation lists rely on and maintain the following invariants:
164 * - each feat_num in the list is known, i.e. we know its type and default value
165 * - each feat_num/is_local combination is unique (old entries are overwritten)
166 * - SP values are always freshly allocated
167 * - list is sorted in increasing order of feature number (faster lookup)
169 static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list,
170 u8 feat_num, bool is_local)
172 struct dccp_feat_entry *entry;
174 list_for_each_entry(entry, fn_list, node)
175 if (entry->feat_num == feat_num && entry->is_local == is_local)
177 else if (entry->feat_num > feat_num)
183 * dccp_feat_entry_new - Central list update routine (called by all others)
184 * @head: list to add to
185 * @feat: feature number
186 * @local: whether the local (1) or remote feature with number @feat is meant
187 * This is the only constructor and serves to ensure the above invariants.
189 static struct dccp_feat_entry *
190 dccp_feat_entry_new(struct list_head *head, u8 feat, bool local)
192 struct dccp_feat_entry *entry;
194 list_for_each_entry(entry, head, node)
195 if (entry->feat_num == feat && entry->is_local == local) {
196 dccp_feat_val_destructor(entry->feat_num, &entry->val);
198 } else if (entry->feat_num > feat) {
203 entry = kmalloc(sizeof(*entry), gfp_any());
205 entry->feat_num = feat;
206 entry->is_local = local;
207 list_add_tail(&entry->node, head);
213 * dccp_feat_push_change - Add/overwrite a Change option in the list
214 * @fn_list: feature-negotiation list to update
215 * @feat: one of %dccp_feature_numbers
216 * @local: whether local (1) or remote (0) @feat_num is meant
217 * @needs_mandatory: whether to use Mandatory feature negotiation options
218 * @fval: pointer to NN/SP value to be inserted (will be copied)
220 static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
221 u8 mandatory, dccp_feat_val *fval)
223 struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
228 new->feat_num = feat;
229 new->is_local = local;
230 new->state = FEAT_INITIALISING;
231 new->needs_confirm = 0;
232 new->empty_confirm = 0;
234 new->needs_mandatory = mandatory;
239 static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
241 list_del(&entry->node);
242 dccp_feat_entry_destructor(entry);
245 void dccp_feat_list_purge(struct list_head *fn_list)
247 struct dccp_feat_entry *entry, *next;
249 list_for_each_entry_safe(entry, next, fn_list, node)
250 dccp_feat_entry_destructor(entry);
251 INIT_LIST_HEAD(fn_list);
253 EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
255 /* generate @to as full clone of @from - @to must not contain any nodes */
256 int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
258 struct dccp_feat_entry *entry, *new;
261 list_for_each_entry(entry, from, node) {
262 new = dccp_feat_clone_entry(entry);
265 list_add_tail(&new->node, to);
270 dccp_feat_list_purge(to);
274 static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
277 case DCCPF_ACK_RATIO:
278 return val <= DCCPF_ACK_RATIO_MAX;
279 case DCCPF_SEQUENCE_WINDOW:
280 return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX;
282 return 0; /* feature unknown - so we can't tell */
285 /* check that SP values are within the ranges defined in RFC 4340 */
286 static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val)
290 return val == DCCPC_CCID2 || val == DCCPC_CCID3;
291 /* Type-check Boolean feature values: */
292 case DCCPF_SHORT_SEQNOS:
293 case DCCPF_ECN_INCAPABLE:
294 case DCCPF_SEND_ACK_VECTOR:
295 case DCCPF_SEND_NDP_COUNT:
296 case DCCPF_DATA_CHECKSUM:
297 case DCCPF_SEND_LEV_RATE:
299 case DCCPF_MIN_CSUM_COVER:
302 return 0; /* feature unknown */
305 static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
307 if (sp_list == NULL || sp_len < 1)
310 if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++))
316 * __feat_register_nn - Register new NN value on socket
317 * @fn: feature-negotiation list to register with
318 * @feat: an NN feature from %dccp_feature_numbers
319 * @mandatory: use Mandatory option if 1
320 * @nn_val: value to register (restricted to 4 bytes)
321 * Note that NN features are local by definition (RFC 4340, 6.3.2).
323 static int __feat_register_nn(struct list_head *fn, u8 feat,
324 u8 mandatory, u64 nn_val)
326 dccp_feat_val fval = { .nn = nn_val };
328 if (dccp_feat_type(feat) != FEAT_NN ||
329 !dccp_feat_is_valid_nn_val(feat, nn_val))
332 /* Don't bother with default values, they will be activated anyway. */
333 if (nn_val - (u64)dccp_feat_default_value(feat) == 0)
336 return dccp_feat_push_change(fn, feat, 1, mandatory, &fval);
340 * __feat_register_sp - Register new SP value/list on socket
341 * @fn: feature-negotiation list to register with
342 * @feat: an SP feature from %dccp_feature_numbers
343 * @is_local: whether the local (1) or the remote (0) @feat is meant
344 * @mandatory: use Mandatory option if 1
345 * @sp_val: SP value followed by optional preference list
346 * @sp_len: length of @sp_val in bytes
348 static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
349 u8 mandatory, u8 const *sp_val, u8 sp_len)
353 if (dccp_feat_type(feat) != FEAT_SP ||
354 !dccp_feat_sp_list_ok(feat, sp_val, sp_len))
357 /* Avoid negotiating alien CCIDs by only advertising supported ones */
358 if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len))
361 if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
364 return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
367 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
368 u8 *val, u8 len, gfp_t gfp)
370 struct dccp_opt_pend *opt;
372 dccp_feat_debug(type, feature, *val);
375 DCCP_WARN("invalid length %d\n", len);
378 /* XXX add further sanity checks */
380 /* check if that feature is already being negotiated */
381 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
382 /* ok we found a negotiation for this option already */
383 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
384 dccp_pr_debug("Replacing old\n");
386 BUG_ON(opt->dccpop_val == NULL);
387 kfree(opt->dccpop_val);
388 opt->dccpop_val = val;
389 opt->dccpop_len = len;
390 opt->dccpop_conf = 0;
395 /* negotiation for a new feature */
396 opt = kmalloc(sizeof(*opt), gfp);
400 opt->dccpop_type = type;
401 opt->dccpop_feat = feature;
402 opt->dccpop_len = len;
403 opt->dccpop_val = val;
404 opt->dccpop_conf = 0;
405 opt->dccpop_sc = NULL;
407 BUG_ON(opt->dccpop_val == NULL);
409 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
413 EXPORT_SYMBOL_GPL(dccp_feat_change);
416 * Tracking features whose value depend on the choice of CCID
418 * This is designed with an extension in mind so that a list walk could be done
419 * before activating any features. However, the existing framework was found to
420 * work satisfactorily up until now, the automatic verification is left open.
421 * When adding new CCIDs, add a corresponding dependency table here.
423 static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local)
425 static const struct ccid_dependency ccid2_dependencies[2][2] = {
427 * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX
428 * feature and Send Ack Vector is an RX feature, `is_local'
429 * needs to be reversed.
431 { /* Dependencies of the receiver-side (remote) CCID2 */
433 .dependent_feat = DCCPF_SEND_ACK_VECTOR,
435 .is_mandatory = true,
440 { /* Dependencies of the sender-side (local) CCID2 */
442 .dependent_feat = DCCPF_SEND_ACK_VECTOR,
444 .is_mandatory = true,
450 static const struct ccid_dependency ccid3_dependencies[2][5] = {
452 * Dependencies of the receiver-side CCID3
454 { /* locally disable Ack Vectors */
455 .dependent_feat = DCCPF_SEND_ACK_VECTOR,
457 .is_mandatory = false,
460 { /* see below why Send Loss Event Rate is on */
461 .dependent_feat = DCCPF_SEND_LEV_RATE,
463 .is_mandatory = true,
466 { /* NDP Count is needed as per RFC 4342, 6.1.1 */
467 .dependent_feat = DCCPF_SEND_NDP_COUNT,
469 .is_mandatory = true,
475 * CCID3 at the TX side: we request that the HC-receiver
476 * will not send Ack Vectors (they will be ignored, so
477 * Mandatory is not set); we enable Send Loss Event Rate
478 * (Mandatory since the implementation does not support
479 * the Loss Intervals option of RFC 4342, 8.6).
480 * The last two options are for peer's information only.
483 .dependent_feat = DCCPF_SEND_ACK_VECTOR,
485 .is_mandatory = false,
489 .dependent_feat = DCCPF_SEND_LEV_RATE,
491 .is_mandatory = true,
494 { /* this CCID does not support Ack Ratio */
495 .dependent_feat = DCCPF_ACK_RATIO,
497 .is_mandatory = false,
500 { /* tell receiver we are sending NDP counts */
501 .dependent_feat = DCCPF_SEND_NDP_COUNT,
503 .is_mandatory = false,
511 return ccid2_dependencies[is_local];
513 return ccid3_dependencies[is_local];
520 * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID
521 * @fn: feature-negotiation list to update
522 * @id: CCID number to track
523 * @is_local: whether TX CCID (1) or RX CCID (0) is meant
524 * This function needs to be called after registering all other features.
526 static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local)
528 const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local);
529 int i, rc = (table == NULL);
531 for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++)
532 if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP)
533 rc = __feat_register_sp(fn, table[i].dependent_feat,
535 table[i].is_mandatory,
538 rc = __feat_register_nn(fn, table[i].dependent_feat,
539 table[i].is_mandatory,
545 * dccp_feat_finalise_settings - Finalise settings before starting negotiation
546 * @dp: client or listening socket (settings will be inherited)
547 * This is called after all registrations (socket initialisation, sysctls, and
548 * sockopt calls), and before sending the first packet containing Change options
549 * (ie. client-Request or server-Response), to ensure internal consistency.
551 int dccp_feat_finalise_settings(struct dccp_sock *dp)
553 struct list_head *fn = &dp->dccps_featneg;
554 struct dccp_feat_entry *entry;
555 int i = 2, ccids[2] = { -1, -1 };
559 * 1) not useful to propagate CCID settings if this host advertises more
560 * than one CCID: the choice of CCID may still change - if this is
561 * the client, or if this is the server and the client sends
562 * singleton CCID values.
563 * 2) since is that propagate_ccid changes the list, we defer changing
564 * the sorted list until after the traversal.
566 list_for_each_entry(entry, fn, node)
567 if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1)
568 ccids[entry->is_local] = entry->val.sp.vec[0];
570 if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i))
576 * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features
577 * It is the server which resolves the dependencies once the CCID has been
578 * fully negotiated. If no CCID has been negotiated, it uses the default CCID.
580 int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq)
582 struct list_head *fn = &dreq->dreq_featneg;
583 struct dccp_feat_entry *entry;
586 for (is_local = 0; is_local <= 1; is_local++) {
587 entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local);
589 if (entry != NULL && !entry->empty_confirm)
590 ccid = entry->val.sp.vec[0];
592 ccid = dccp_feat_default_value(DCCPF_CCID);
594 if (dccp_feat_propagate_ccid(fn, ccid, is_local))
600 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
602 struct dccp_sock *dp = dccp_sk(sk);
603 struct dccp_minisock *dmsk = dccp_msk(sk);
604 /* figure out if we are changing our CCID or the peer's */
605 const int rx = type == DCCPO_CHANGE_R;
606 const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
607 struct ccid *new_ccid;
609 /* Check if nothing is being changed. */
610 if (ccid_nr == new_ccid_nr)
613 new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
614 if (new_ccid == NULL)
618 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
619 dp->dccps_hc_rx_ccid = new_ccid;
620 dmsk->dccpms_rx_ccid = new_ccid_nr;
622 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
623 dp->dccps_hc_tx_ccid = new_ccid;
624 dmsk->dccpms_tx_ccid = new_ccid_nr;
630 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
632 dccp_feat_debug(type, feat, val);
636 return dccp_feat_update_ccid(sk, type, val);
638 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
639 dccp_feat_typename(type), feat);
645 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
648 struct dccp_sock *dp = dccp_sk(sk);
649 u8 *spref, slen, *res = NULL;
650 int i, j, rc, agree = 1;
652 BUG_ON(rpref == NULL);
654 /* check if we are the black sheep */
655 if (dp->dccps_role == DCCP_ROLE_CLIENT) {
658 rpref = opt->dccpop_val;
659 rlen = opt->dccpop_len;
661 spref = opt->dccpop_val;
662 slen = opt->dccpop_len;
665 * Now we have server preference list in spref and client preference in
668 BUG_ON(spref == NULL);
669 BUG_ON(rpref == NULL);
671 /* FIXME sanity check vals */
673 /* Are values in any order? XXX Lame "algorithm" here */
674 for (i = 0; i < slen; i++) {
675 for (j = 0; j < rlen; j++) {
676 if (spref[i] == rpref[j]) {
685 /* we didn't agree on anything */
687 /* confirm previous value */
688 switch (opt->dccpop_feat) {
690 /* XXX did i get this right? =P */
691 if (opt->dccpop_type == DCCPO_CHANGE_L)
692 res = &dccp_msk(sk)->dccpms_tx_ccid;
694 res = &dccp_msk(sk)->dccpms_rx_ccid;
698 DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
699 /* XXX implement res */
703 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
704 agree = 0; /* this is used for mandatory options... */
707 /* need to put result and our preference list */
708 rlen = 1 + opt->dccpop_len;
709 rpref = kmalloc(rlen, GFP_ATOMIC);
714 memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
716 /* put it in the "confirm queue" */
717 if (opt->dccpop_sc == NULL) {
718 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
719 if (opt->dccpop_sc == NULL) {
724 /* recycle the confirm slot */
725 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
726 kfree(opt->dccpop_sc->dccpoc_val);
727 dccp_pr_debug("recycling confirm slot\n");
729 memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
731 opt->dccpop_sc->dccpoc_val = rpref;
732 opt->dccpop_sc->dccpoc_len = rlen;
734 /* update the option on our side [we are about to send the confirm] */
735 rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
737 kfree(opt->dccpop_sc->dccpoc_val);
738 kfree(opt->dccpop_sc);
739 opt->dccpop_sc = NULL;
743 dccp_pr_debug("Will confirm %d\n", *rpref);
745 /* say we want to change to X but we just got a confirm X, suppress our
748 if (!opt->dccpop_conf) {
749 if (*opt->dccpop_val == *res)
750 opt->dccpop_conf = 1;
751 dccp_pr_debug("won't ask for change of same feature\n");
754 return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
757 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
759 struct dccp_minisock *dmsk = dccp_msk(sk);
760 struct dccp_opt_pend *opt;
765 * We received a CHANGE. We gotta match it against our own preference
766 * list. If we got a CHANGE_R it means it's a change for us, so we need
767 * to compare our CHANGE_L list.
769 if (type == DCCPO_CHANGE_L)
774 /* find our preference list for this feature */
775 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
776 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
779 /* find the winner from the two preference lists */
780 rc = dccp_feat_reconcile(sk, opt, val, len);
784 /* We didn't deal with the change. This can happen if we have no
785 * preference list for the feature. In fact, it just shouldn't
786 * happen---if we understand a feature, we should have a preference list
787 * with at least the default value.
794 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
796 struct dccp_opt_pend *opt;
797 struct dccp_minisock *dmsk = dccp_msk(sk);
801 /* NN features must be Change L (sec. 6.3.2) */
802 if (type != DCCPO_CHANGE_L) {
803 dccp_pr_debug("received %s for NN feature %d\n",
804 dccp_feat_typename(type), feature);
808 /* XXX sanity check opt val */
810 /* copy option so we can confirm it */
811 opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
815 copy = kmemdup(val, len, GFP_ATOMIC);
821 opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
822 opt->dccpop_feat = feature;
823 opt->dccpop_val = copy;
824 opt->dccpop_len = len;
827 rc = dccp_feat_update(sk, type, feature, *val);
829 kfree(opt->dccpop_val);
834 dccp_feat_debug(type, feature, *copy);
836 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
841 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
844 /* XXX check if other confirms for that are queued and recycle slot */
845 struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
848 /* XXX what do we do? Ignoring should be fine. It's a change
856 opt->dccpop_type = DCCPO_CONFIRM_R;
859 opt->dccpop_type = DCCPO_CONFIRM_L;
862 DCCP_WARN("invalid type %d\n", type);
866 opt->dccpop_feat = feature;
867 opt->dccpop_val = NULL;
871 dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
873 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
876 static void dccp_feat_flush_confirm(struct sock *sk)
878 struct dccp_minisock *dmsk = dccp_msk(sk);
879 /* Check if there is anything to confirm in the first place */
880 int yes = !list_empty(&dmsk->dccpms_conf);
883 struct dccp_opt_pend *opt;
885 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
886 if (opt->dccpop_conf) {
896 /* OK there is something to confirm... */
897 /* XXX check if packet is in flight? Send delayed ack?? */
898 if (sk->sk_state == DCCP_OPEN)
902 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
906 /* Ignore Change requests other than during connection setup */
907 if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
909 dccp_feat_debug(type, feature, *val);
911 /* figure out if it's SP or NN feature */
913 /* deal with SP features */
915 rc = dccp_feat_sp(sk, type, feature, val, len);
918 /* deal with NN features */
919 case DCCPF_ACK_RATIO:
920 rc = dccp_feat_nn(sk, type, feature, val, len);
923 /* XXX implement other features */
925 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
926 dccp_feat_typename(type), feature);
931 /* check if there were problems changing features */
933 /* If we don't agree on SP, we sent a confirm for old value.
934 * However we propagate rc to caller in case option was
937 if (rc != DCCP_FEAT_SP_NOAGREE)
938 dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
941 /* generate the confirm [if required] */
942 dccp_feat_flush_confirm(sk);
947 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
949 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
953 struct dccp_opt_pend *opt;
954 struct dccp_minisock *dmsk = dccp_msk(sk);
956 int all_confirmed = 1;
958 /* Ignore Confirm options other than during connection setup */
959 if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
961 dccp_feat_debug(type, feature, *val);
963 /* locate our change request */
965 case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
966 case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
967 default: DCCP_WARN("invalid type %d\n", type);
971 /* XXX sanity check feature value */
973 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
974 if (!opt->dccpop_conf && opt->dccpop_type == t &&
975 opt->dccpop_feat == feature) {
977 dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
979 /* XXX do sanity check */
981 opt->dccpop_conf = 1;
983 /* We got a confirmation---change the option */
984 dccp_feat_update(sk, opt->dccpop_type,
985 opt->dccpop_feat, *val);
987 /* XXX check the return value of dccp_feat_update */
991 if (!opt->dccpop_conf)
996 dccp_pr_debug("%s(%d, ...) never requested\n",
997 dccp_feat_typename(type), feature);
1001 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
1003 void dccp_feat_clean(struct dccp_minisock *dmsk)
1005 struct dccp_opt_pend *opt, *next;
1007 list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
1009 BUG_ON(opt->dccpop_val == NULL);
1010 kfree(opt->dccpop_val);
1012 if (opt->dccpop_sc != NULL) {
1013 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
1014 kfree(opt->dccpop_sc->dccpoc_val);
1015 kfree(opt->dccpop_sc);
1020 INIT_LIST_HEAD(&dmsk->dccpms_pending);
1022 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
1023 BUG_ON(opt == NULL);
1024 if (opt->dccpop_val != NULL)
1025 kfree(opt->dccpop_val);
1028 INIT_LIST_HEAD(&dmsk->dccpms_conf);
1031 EXPORT_SYMBOL_GPL(dccp_feat_clean);
1033 /* this is to be called only when a listening sock creates its child. It is
1034 * assumed by the function---the confirm is not duplicated, but rather it is
1037 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
1039 struct dccp_minisock *olddmsk = dccp_msk(oldsk);
1040 struct dccp_minisock *newdmsk = dccp_msk(newsk);
1041 struct dccp_opt_pend *opt;
1044 INIT_LIST_HEAD(&newdmsk->dccpms_pending);
1045 INIT_LIST_HEAD(&newdmsk->dccpms_conf);
1047 list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
1048 struct dccp_opt_pend *newopt;
1049 /* copy the value of the option */
1050 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
1055 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
1056 if (newopt == NULL) {
1061 /* insert the option */
1062 newopt->dccpop_val = val;
1063 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
1065 /* XXX what happens with backlogs and multiple connections at
1068 /* the master socket no longer needs to worry about confirms */
1069 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
1071 /* reset state for a new socket */
1072 opt->dccpop_conf = 0;
1075 /* XXX not doing anything about the conf queue */
1081 dccp_feat_clean(newdmsk);
1086 EXPORT_SYMBOL_GPL(dccp_feat_clone);
1088 int dccp_feat_init(struct sock *sk)
1090 struct dccp_sock *dp = dccp_sk(sk);
1091 struct dccp_minisock *dmsk = dccp_msk(sk);
1094 INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */
1095 INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */
1098 rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
1099 &dmsk->dccpms_tx_ccid, 1);
1104 rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
1105 &dmsk->dccpms_rx_ccid, 1);
1110 rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
1111 dmsk->dccpms_ack_ratio);
1116 EXPORT_SYMBOL_GPL(dccp_feat_init);
1118 #ifdef CONFIG_IP_DCCP_DEBUG
1119 const char *dccp_feat_typename(const u8 type)
1122 case DCCPO_CHANGE_L: return("ChangeL");
1123 case DCCPO_CONFIRM_L: return("ConfirmL");
1124 case DCCPO_CHANGE_R: return("ChangeR");
1125 case DCCPO_CONFIRM_R: return("ConfirmR");
1126 /* the following case must not appear in feature negotation */
1127 default: dccp_pr_debug("unknown type %d [BUG!]\n", type);
1132 EXPORT_SYMBOL_GPL(dccp_feat_typename);
1134 const char *dccp_feat_name(const u8 feat)
1136 static const char *feature_names[] = {
1137 [DCCPF_RESERVED] = "Reserved",
1138 [DCCPF_CCID] = "CCID",
1139 [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos",
1140 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
1141 [DCCPF_ECN_INCAPABLE] = "ECN Incapable",
1142 [DCCPF_ACK_RATIO] = "Ack Ratio",
1143 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
1144 [DCCPF_SEND_NDP_COUNT] = "Send NDP Count",
1145 [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage",
1146 [DCCPF_DATA_CHECKSUM] = "Send Data Checksum",
1148 if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
1149 return feature_names[DCCPF_RESERVED];
1151 if (feat == DCCPF_SEND_LEV_RATE)
1152 return "Send Loss Event Rate";
1153 if (feat >= DCCPF_MIN_CCID_SPECIFIC)
1154 return "CCID-specific";
1156 return feature_names[feat];
1159 EXPORT_SYMBOL_GPL(dccp_feat_name);
1160 #endif /* CONFIG_IP_DCCP_DEBUG */