4 * An implementation of the DCCP protocol
5 * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
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.
13 #include <linux/config.h>
14 #include <linux/module.h>
20 #define DCCP_FEAT_SP_NOAGREE (-123)
22 int dccp_feat_change(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len,
25 struct dccp_minisock *dmsk = dccp_msk(sk);
26 struct dccp_opt_pend *opt;
28 dccp_pr_debug("feat change type=%d feat=%d\n", type, feature);
30 /* XXX sanity check feat change request */
32 /* check if that feature is already being negotiated */
33 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
34 /* ok we found a negotiation for this option already */
35 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
36 dccp_pr_debug("Replacing old\n");
38 BUG_ON(opt->dccpop_val == NULL);
39 kfree(opt->dccpop_val);
40 opt->dccpop_val = val;
41 opt->dccpop_len = len;
47 /* negotiation for a new feature */
48 opt = kmalloc(sizeof(*opt), gfp);
52 opt->dccpop_type = type;
53 opt->dccpop_feat = feature;
54 opt->dccpop_len = len;
55 opt->dccpop_val = val;
57 opt->dccpop_sc = NULL;
59 BUG_ON(opt->dccpop_val == NULL);
61 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
65 EXPORT_SYMBOL_GPL(dccp_feat_change);
67 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
69 struct dccp_sock *dp = dccp_sk(sk);
70 struct dccp_minisock *dmsk = dccp_msk(sk);
71 /* figure out if we are changing our CCID or the peer's */
72 const int rx = type == DCCPO_CHANGE_R;
73 const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
74 struct ccid *new_ccid;
76 /* Check if nothing is being changed. */
77 if (ccid_nr == new_ccid_nr)
80 new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
85 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
86 dp->dccps_hc_rx_ccid = new_ccid;
87 dmsk->dccpms_rx_ccid = new_ccid_nr;
89 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
90 dp->dccps_hc_tx_ccid = new_ccid;
91 dmsk->dccpms_tx_ccid = new_ccid_nr;
97 /* XXX taking only u8 vals */
98 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
100 dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val);
104 return dccp_feat_update_ccid(sk, type, val);
106 dccp_pr_debug("IMPLEMENT changing [%d] feat %d to %d\n",
113 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
116 struct dccp_sock *dp = dccp_sk(sk);
117 u8 *spref, slen, *res = NULL;
118 int i, j, rc, agree = 1;
120 BUG_ON(rpref == NULL);
122 /* check if we are the black sheep */
123 if (dp->dccps_role == DCCP_ROLE_CLIENT) {
126 rpref = opt->dccpop_val;
127 rlen = opt->dccpop_len;
129 spref = opt->dccpop_val;
130 slen = opt->dccpop_len;
133 * Now we have server preference list in spref and client preference in
136 BUG_ON(spref == NULL);
137 BUG_ON(rpref == NULL);
139 /* FIXME sanity check vals */
141 /* Are values in any order? XXX Lame "algorithm" here */
142 /* XXX assume values are 1 byte */
143 for (i = 0; i < slen; i++) {
144 for (j = 0; j < rlen; j++) {
145 if (spref[i] == rpref[j]) {
154 /* we didn't agree on anything */
156 /* confirm previous value */
157 switch (opt->dccpop_feat) {
159 /* XXX did i get this right? =P */
160 if (opt->dccpop_type == DCCPO_CHANGE_L)
161 res = &dccp_msk(sk)->dccpms_tx_ccid;
163 res = &dccp_msk(sk)->dccpms_rx_ccid;
167 WARN_ON(1); /* XXX implement res */
171 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
172 agree = 0; /* this is used for mandatory options... */
175 /* need to put result and our preference list */
176 /* XXX assume 1 byte vals */
177 rlen = 1 + opt->dccpop_len;
178 rpref = kmalloc(rlen, GFP_ATOMIC);
183 memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
185 /* put it in the "confirm queue" */
186 if (opt->dccpop_sc == NULL) {
187 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
188 if (opt->dccpop_sc == NULL) {
193 /* recycle the confirm slot */
194 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
195 kfree(opt->dccpop_sc->dccpoc_val);
196 dccp_pr_debug("recycling confirm slot\n");
198 memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
200 opt->dccpop_sc->dccpoc_val = rpref;
201 opt->dccpop_sc->dccpoc_len = rlen;
203 /* update the option on our side [we are about to send the confirm] */
204 rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
206 kfree(opt->dccpop_sc->dccpoc_val);
207 kfree(opt->dccpop_sc);
212 dccp_pr_debug("Will confirm %d\n", *rpref);
214 /* say we want to change to X but we just got a confirm X, suppress our
217 if (!opt->dccpop_conf) {
218 if (*opt->dccpop_val == *res)
219 opt->dccpop_conf = 1;
220 dccp_pr_debug("won't ask for change of same feature\n");
223 return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
226 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
228 struct dccp_minisock *dmsk = dccp_msk(sk);
229 struct dccp_opt_pend *opt;
234 * We received a CHANGE. We gotta match it against our own preference
235 * list. If we got a CHANGE_R it means it's a change for us, so we need
236 * to compare our CHANGE_L list.
238 if (type == DCCPO_CHANGE_L)
243 /* find our preference list for this feature */
244 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
245 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
248 /* find the winner from the two preference lists */
249 rc = dccp_feat_reconcile(sk, opt, val, len);
253 /* We didn't deal with the change. This can happen if we have no
254 * preference list for the feature. In fact, it just shouldn't
255 * happen---if we understand a feature, we should have a preference list
256 * with at least the default value.
263 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
265 struct dccp_opt_pend *opt;
266 struct dccp_minisock *dmsk = dccp_msk(sk);
270 /* NN features must be change L */
271 if (type == DCCPO_CHANGE_R) {
272 dccp_pr_debug("received CHANGE_R %d for NN feat %d\n",
277 /* XXX sanity check opt val */
279 /* copy option so we can confirm it */
280 opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
284 copy = kmalloc(len, GFP_ATOMIC);
289 memcpy(copy, val, len);
291 opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
292 opt->dccpop_feat = feature;
293 opt->dccpop_val = copy;
294 opt->dccpop_len = len;
297 rc = dccp_feat_update(sk, type, feature, *val);
299 kfree(opt->dccpop_val);
304 dccp_pr_debug("Confirming NN feature %d (val=%d)\n", feature, *copy);
305 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
310 static void dccp_feat_empty_confirm(struct sock *sk, u8 type, u8 feature)
312 struct dccp_minisock *dmsk = dccp_msk(sk);
313 /* XXX check if other confirms for that are queued and recycle slot */
314 struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
317 /* XXX what do we do? Ignoring should be fine. It's a change
323 opt->dccpop_type = type == DCCPO_CHANGE_L ? DCCPO_CONFIRM_R :
325 opt->dccpop_feat = feature;
330 dccp_pr_debug("Empty confirm feature %d type %d\n", feature, type);
331 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
334 static void dccp_feat_flush_confirm(struct sock *sk)
336 struct dccp_minisock *dmsk = dccp_msk(sk);
337 /* Check if there is anything to confirm in the first place */
338 int yes = !list_empty(&dmsk->dccpms_conf);
341 struct dccp_opt_pend *opt;
343 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
344 if (opt->dccpop_conf) {
354 /* OK there is something to confirm... */
355 /* XXX check if packet is in flight? Send delayed ack?? */
356 if (sk->sk_state == DCCP_OPEN)
360 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
364 dccp_pr_debug("got feat change type=%d feat=%d\n", type, feature);
366 /* figure out if it's SP or NN feature */
368 /* deal with SP features */
370 rc = dccp_feat_sp(sk, type, feature, val, len);
373 /* deal with NN features */
374 case DCCPF_ACK_RATIO:
375 rc = dccp_feat_nn(sk, type, feature, val, len);
378 /* XXX implement other features */
384 /* check if there were problems changing features */
386 /* If we don't agree on SP, we sent a confirm for old value.
387 * However we propagate rc to caller in case option was
390 if (rc != DCCP_FEAT_SP_NOAGREE)
391 dccp_feat_empty_confirm(sk, type, feature);
394 /* generate the confirm [if required] */
395 dccp_feat_flush_confirm(sk);
400 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
402 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
406 struct dccp_opt_pend *opt;
407 struct dccp_minisock *dmsk = dccp_msk(sk);
409 int all_confirmed = 1;
411 dccp_pr_debug("got feat confirm type=%d feat=%d\n", type, feature);
413 /* XXX sanity check type & feat */
415 /* locate our change request */
416 t = type == DCCPO_CONFIRM_L ? DCCPO_CHANGE_R : DCCPO_CHANGE_L;
418 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
419 if (!opt->dccpop_conf && opt->dccpop_type == t &&
420 opt->dccpop_feat == feature) {
422 /* XXX do sanity check */
424 opt->dccpop_conf = 1;
426 /* We got a confirmation---change the option */
427 dccp_feat_update(sk, opt->dccpop_type,
428 opt->dccpop_feat, *val);
430 dccp_pr_debug("feat %d type %d confirmed %d\n",
431 feature, type, *val);
436 if (!opt->dccpop_conf)
440 /* fix re-transmit timer */
441 /* XXX gotta make sure that no option negotiation occurs during
442 * connection shutdown. Consider that the CLOSEREQ is sent and timer is
443 * on. if all options are confirmed it might kill timer which should
444 * remain alive until close is received.
447 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
448 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
452 dccp_pr_debug("feat %d type %d never requested\n",
457 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
459 void dccp_feat_clean(struct sock *sk)
461 struct dccp_minisock *dmsk = dccp_msk(sk);
462 struct dccp_opt_pend *opt, *next;
464 list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
466 BUG_ON(opt->dccpop_val == NULL);
467 kfree(opt->dccpop_val);
469 if (opt->dccpop_sc != NULL) {
470 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
471 kfree(opt->dccpop_sc->dccpoc_val);
472 kfree(opt->dccpop_sc);
477 INIT_LIST_HEAD(&dmsk->dccpms_pending);
479 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
481 if (opt->dccpop_val != NULL)
482 kfree(opt->dccpop_val);
485 INIT_LIST_HEAD(&dmsk->dccpms_conf);
488 EXPORT_SYMBOL_GPL(dccp_feat_clean);
490 /* this is to be called only when a listening sock creates its child. It is
491 * assumed by the function---the confirm is not duplicated, but rather it is
494 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
496 struct dccp_minisock *olddmsk = dccp_msk(oldsk);
497 struct dccp_minisock *newdmsk = dccp_msk(newsk);
498 struct dccp_opt_pend *opt;
501 INIT_LIST_HEAD(&newdmsk->dccpms_pending);
502 INIT_LIST_HEAD(&newdmsk->dccpms_conf);
504 list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
505 struct dccp_opt_pend *newopt;
506 /* copy the value of the option */
507 u8 *val = kmalloc(opt->dccpop_len, GFP_ATOMIC);
511 memcpy(val, opt->dccpop_val, opt->dccpop_len);
513 newopt = kmalloc(sizeof(*newopt), GFP_ATOMIC);
514 if (newopt == NULL) {
519 /* insert the option */
520 memcpy(newopt, opt, sizeof(*newopt));
521 newopt->dccpop_val = val;
522 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
524 /* XXX what happens with backlogs and multiple connections at
527 /* the master socket no longer needs to worry about confirms */
528 opt->dccpop_sc = 0; /* it's not a memleak---new socket has it */
530 /* reset state for a new socket */
531 opt->dccpop_conf = 0;
534 /* XXX not doing anything about the conf queue */
540 dccp_feat_clean(newsk);
545 EXPORT_SYMBOL_GPL(dccp_feat_clone);
547 static int __dccp_feat_init(struct sock *sk, u8 type, u8 feat, u8 *val, u8 len)
550 u8 *copy = kmalloc(len, GFP_KERNEL);
553 memcpy(copy, val, len);
554 rc = dccp_feat_change(sk, type, feat, copy, len, GFP_KERNEL);
561 int dccp_feat_init(struct sock *sk)
563 struct dccp_minisock *dmsk = dccp_msk(sk);
566 INIT_LIST_HEAD(&dmsk->dccpms_pending);
567 INIT_LIST_HEAD(&dmsk->dccpms_conf);
570 rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_CCID,
571 &dmsk->dccpms_tx_ccid, 1);
576 rc = __dccp_feat_init(sk, DCCPO_CHANGE_R, DCCPF_CCID,
577 &dmsk->dccpms_rx_ccid, 1);
582 rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
583 &dmsk->dccpms_ack_ratio, 1);
588 EXPORT_SYMBOL_GPL(dccp_feat_init);