4 * An implementation of the DCCP protocol
5 * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
9 * o All currently known SP features have 1-byte quantities. If in the future
10 * extensions of RFCs 4340..42 define features with item lengths larger than
11 * one byte, a feature-specific extension of the code will be required.
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
19 #include <linux/module.h>
24 #define DCCP_FEAT_SP_NOAGREE (-123)
26 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
27 u8 *val, u8 len, gfp_t gfp)
29 struct dccp_opt_pend *opt;
31 dccp_feat_debug(type, feature, *val);
34 DCCP_WARN("invalid length %d\n", len);
37 /* XXX add further sanity checks */
39 /* check if that feature is already being negotiated */
40 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
41 /* ok we found a negotiation for this option already */
42 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
43 dccp_pr_debug("Replacing old\n");
45 BUG_ON(opt->dccpop_val == NULL);
46 kfree(opt->dccpop_val);
47 opt->dccpop_val = val;
48 opt->dccpop_len = len;
54 /* negotiation for a new feature */
55 opt = kmalloc(sizeof(*opt), gfp);
59 opt->dccpop_type = type;
60 opt->dccpop_feat = feature;
61 opt->dccpop_len = len;
62 opt->dccpop_val = val;
64 opt->dccpop_sc = NULL;
66 BUG_ON(opt->dccpop_val == NULL);
68 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
72 EXPORT_SYMBOL_GPL(dccp_feat_change);
74 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
76 struct dccp_sock *dp = dccp_sk(sk);
77 struct dccp_minisock *dmsk = dccp_msk(sk);
78 /* figure out if we are changing our CCID or the peer's */
79 const int rx = type == DCCPO_CHANGE_R;
80 const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
81 struct ccid *new_ccid;
83 /* Check if nothing is being changed. */
84 if (ccid_nr == new_ccid_nr)
87 new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
92 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
93 dp->dccps_hc_rx_ccid = new_ccid;
94 dmsk->dccpms_rx_ccid = new_ccid_nr;
96 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
97 dp->dccps_hc_tx_ccid = new_ccid;
98 dmsk->dccpms_tx_ccid = new_ccid_nr;
104 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
106 dccp_feat_debug(type, feat, val);
110 return dccp_feat_update_ccid(sk, type, val);
112 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
113 dccp_feat_typename(type), feat);
119 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
122 struct dccp_sock *dp = dccp_sk(sk);
123 u8 *spref, slen, *res = NULL;
124 int i, j, rc, agree = 1;
126 BUG_ON(rpref == NULL);
128 /* check if we are the black sheep */
129 if (dp->dccps_role == DCCP_ROLE_CLIENT) {
132 rpref = opt->dccpop_val;
133 rlen = opt->dccpop_len;
135 spref = opt->dccpop_val;
136 slen = opt->dccpop_len;
139 * Now we have server preference list in spref and client preference in
142 BUG_ON(spref == NULL);
143 BUG_ON(rpref == NULL);
145 /* FIXME sanity check vals */
147 /* Are values in any order? XXX Lame "algorithm" here */
148 for (i = 0; i < slen; i++) {
149 for (j = 0; j < rlen; j++) {
150 if (spref[i] == rpref[j]) {
159 /* we didn't agree on anything */
161 /* confirm previous value */
162 switch (opt->dccpop_feat) {
164 /* XXX did i get this right? =P */
165 if (opt->dccpop_type == DCCPO_CHANGE_L)
166 res = &dccp_msk(sk)->dccpms_tx_ccid;
168 res = &dccp_msk(sk)->dccpms_rx_ccid;
172 DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
173 /* XXX implement res */
177 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
178 agree = 0; /* this is used for mandatory options... */
181 /* need to put result and our preference list */
182 rlen = 1 + opt->dccpop_len;
183 rpref = kmalloc(rlen, GFP_ATOMIC);
188 memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
190 /* put it in the "confirm queue" */
191 if (opt->dccpop_sc == NULL) {
192 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
193 if (opt->dccpop_sc == NULL) {
198 /* recycle the confirm slot */
199 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
200 kfree(opt->dccpop_sc->dccpoc_val);
201 dccp_pr_debug("recycling confirm slot\n");
203 memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
205 opt->dccpop_sc->dccpoc_val = rpref;
206 opt->dccpop_sc->dccpoc_len = rlen;
208 /* update the option on our side [we are about to send the confirm] */
209 rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
211 kfree(opt->dccpop_sc->dccpoc_val);
212 kfree(opt->dccpop_sc);
213 opt->dccpop_sc = NULL;
217 dccp_pr_debug("Will confirm %d\n", *rpref);
219 /* say we want to change to X but we just got a confirm X, suppress our
222 if (!opt->dccpop_conf) {
223 if (*opt->dccpop_val == *res)
224 opt->dccpop_conf = 1;
225 dccp_pr_debug("won't ask for change of same feature\n");
228 return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
231 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
233 struct dccp_minisock *dmsk = dccp_msk(sk);
234 struct dccp_opt_pend *opt;
239 * We received a CHANGE. We gotta match it against our own preference
240 * list. If we got a CHANGE_R it means it's a change for us, so we need
241 * to compare our CHANGE_L list.
243 if (type == DCCPO_CHANGE_L)
248 /* find our preference list for this feature */
249 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
250 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
253 /* find the winner from the two preference lists */
254 rc = dccp_feat_reconcile(sk, opt, val, len);
258 /* We didn't deal with the change. This can happen if we have no
259 * preference list for the feature. In fact, it just shouldn't
260 * happen---if we understand a feature, we should have a preference list
261 * with at least the default value.
268 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
270 struct dccp_opt_pend *opt;
271 struct dccp_minisock *dmsk = dccp_msk(sk);
275 /* NN features must be Change L (sec. 6.3.2) */
276 if (type != DCCPO_CHANGE_L) {
277 dccp_pr_debug("received %s for NN feature %d\n",
278 dccp_feat_typename(type), feature);
282 /* XXX sanity check opt val */
284 /* copy option so we can confirm it */
285 opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
289 copy = kmemdup(val, len, GFP_ATOMIC);
295 opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
296 opt->dccpop_feat = feature;
297 opt->dccpop_val = copy;
298 opt->dccpop_len = len;
301 rc = dccp_feat_update(sk, type, feature, *val);
303 kfree(opt->dccpop_val);
308 dccp_feat_debug(type, feature, *copy);
310 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
315 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
318 /* XXX check if other confirms for that are queued and recycle slot */
319 struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
322 /* XXX what do we do? Ignoring should be fine. It's a change
330 opt->dccpop_type = DCCPO_CONFIRM_R;
333 opt->dccpop_type = DCCPO_CONFIRM_L;
336 DCCP_WARN("invalid type %d\n", type);
340 opt->dccpop_feat = feature;
341 opt->dccpop_val = NULL;
345 dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
347 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
350 static void dccp_feat_flush_confirm(struct sock *sk)
352 struct dccp_minisock *dmsk = dccp_msk(sk);
353 /* Check if there is anything to confirm in the first place */
354 int yes = !list_empty(&dmsk->dccpms_conf);
357 struct dccp_opt_pend *opt;
359 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
360 if (opt->dccpop_conf) {
370 /* OK there is something to confirm... */
371 /* XXX check if packet is in flight? Send delayed ack?? */
372 if (sk->sk_state == DCCP_OPEN)
376 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
380 dccp_feat_debug(type, feature, *val);
382 /* figure out if it's SP or NN feature */
384 /* deal with SP features */
386 rc = dccp_feat_sp(sk, type, feature, val, len);
389 /* deal with NN features */
390 case DCCPF_ACK_RATIO:
391 rc = dccp_feat_nn(sk, type, feature, val, len);
394 /* XXX implement other features */
396 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
397 dccp_feat_typename(type), feature);
402 /* check if there were problems changing features */
404 /* If we don't agree on SP, we sent a confirm for old value.
405 * However we propagate rc to caller in case option was
408 if (rc != DCCP_FEAT_SP_NOAGREE)
409 dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
412 /* generate the confirm [if required] */
413 dccp_feat_flush_confirm(sk);
418 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
420 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
424 struct dccp_opt_pend *opt;
425 struct dccp_minisock *dmsk = dccp_msk(sk);
427 int all_confirmed = 1;
429 dccp_feat_debug(type, feature, *val);
431 /* locate our change request */
433 case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
434 case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
435 default: DCCP_WARN("invalid type %d\n", type);
439 /* XXX sanity check feature value */
441 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
442 if (!opt->dccpop_conf && opt->dccpop_type == t &&
443 opt->dccpop_feat == feature) {
445 dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
447 /* XXX do sanity check */
449 opt->dccpop_conf = 1;
451 /* We got a confirmation---change the option */
452 dccp_feat_update(sk, opt->dccpop_type,
453 opt->dccpop_feat, *val);
455 /* XXX check the return value of dccp_feat_update */
459 if (!opt->dccpop_conf)
463 /* fix re-transmit timer */
464 /* XXX gotta make sure that no option negotiation occurs during
465 * connection shutdown. Consider that the CLOSEREQ is sent and timer is
466 * on. if all options are confirmed it might kill timer which should
467 * remain alive until close is received.
470 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
471 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
475 dccp_pr_debug("%s(%d, ...) never requested\n",
476 dccp_feat_typename(type), feature);
480 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
482 void dccp_feat_clean(struct dccp_minisock *dmsk)
484 struct dccp_opt_pend *opt, *next;
486 list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
488 BUG_ON(opt->dccpop_val == NULL);
489 kfree(opt->dccpop_val);
491 if (opt->dccpop_sc != NULL) {
492 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
493 kfree(opt->dccpop_sc->dccpoc_val);
494 kfree(opt->dccpop_sc);
499 INIT_LIST_HEAD(&dmsk->dccpms_pending);
501 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
503 if (opt->dccpop_val != NULL)
504 kfree(opt->dccpop_val);
507 INIT_LIST_HEAD(&dmsk->dccpms_conf);
510 EXPORT_SYMBOL_GPL(dccp_feat_clean);
512 /* this is to be called only when a listening sock creates its child. It is
513 * assumed by the function---the confirm is not duplicated, but rather it is
516 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
518 struct dccp_minisock *olddmsk = dccp_msk(oldsk);
519 struct dccp_minisock *newdmsk = dccp_msk(newsk);
520 struct dccp_opt_pend *opt;
523 INIT_LIST_HEAD(&newdmsk->dccpms_pending);
524 INIT_LIST_HEAD(&newdmsk->dccpms_conf);
526 list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
527 struct dccp_opt_pend *newopt;
528 /* copy the value of the option */
529 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
534 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
535 if (newopt == NULL) {
540 /* insert the option */
541 newopt->dccpop_val = val;
542 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
544 /* XXX what happens with backlogs and multiple connections at
547 /* the master socket no longer needs to worry about confirms */
548 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
550 /* reset state for a new socket */
551 opt->dccpop_conf = 0;
554 /* XXX not doing anything about the conf queue */
560 dccp_feat_clean(newdmsk);
565 EXPORT_SYMBOL_GPL(dccp_feat_clone);
567 static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
571 u8 *copy = kmemdup(val, len, GFP_KERNEL);
574 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
581 int dccp_feat_init(struct dccp_minisock *dmsk)
585 INIT_LIST_HEAD(&dmsk->dccpms_pending);
586 INIT_LIST_HEAD(&dmsk->dccpms_conf);
589 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
590 &dmsk->dccpms_tx_ccid, 1);
595 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
596 &dmsk->dccpms_rx_ccid, 1);
601 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
602 &dmsk->dccpms_ack_ratio, 1);
607 EXPORT_SYMBOL_GPL(dccp_feat_init);
609 #ifdef CONFIG_IP_DCCP_DEBUG
610 const char *dccp_feat_typename(const u8 type)
613 case DCCPO_CHANGE_L: return("ChangeL");
614 case DCCPO_CONFIRM_L: return("ConfirmL");
615 case DCCPO_CHANGE_R: return("ChangeR");
616 case DCCPO_CONFIRM_R: return("ConfirmR");
617 /* the following case must not appear in feature negotation */
618 default: dccp_pr_debug("unknown type %d [BUG!]\n", type);
623 EXPORT_SYMBOL_GPL(dccp_feat_typename);
625 const char *dccp_feat_name(const u8 feat)
627 static const char *feature_names[] = {
628 [DCCPF_RESERVED] = "Reserved",
629 [DCCPF_CCID] = "CCID",
630 [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos",
631 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
632 [DCCPF_ECN_INCAPABLE] = "ECN Incapable",
633 [DCCPF_ACK_RATIO] = "Ack Ratio",
634 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
635 [DCCPF_SEND_NDP_COUNT] = "Send NDP Count",
636 [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage",
637 [DCCPF_DATA_CHECKSUM] = "Send Data Checksum",
639 if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
640 return feature_names[DCCPF_RESERVED];
642 if (feat >= DCCPF_MIN_CCID_SPECIFIC)
643 return "CCID-specific";
645 return feature_names[feat];
648 EXPORT_SYMBOL_GPL(dccp_feat_name);
649 #endif /* CONFIG_IP_DCCP_DEBUG */