/*
* net/dccp/feat.c
*
- * An implementation of the DCCP protocol
- * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ * Feature negotiation for the DCCP protocol (RFC 4340, section 6)
+ *
+ * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk>
+ * Rewrote from scratch, some bits from earlier code by
+ * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
*
* ASSUMPTIONS
* -----------
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
-
#include <linux/module.h>
-
#include "ccid.h"
#include "feat.h"
-#define DCCP_FEAT_SP_NOAGREE (-123)
-
/*
* Feature activation handlers.
*
return 0;
}
-static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
-{
- struct dccp_sock *dp = dccp_sk(sk);
- struct dccp_minisock *dmsk = dccp_msk(sk);
- /* figure out if we are changing our CCID or the peer's */
- const int rx = type == DCCPO_CHANGE_R;
- const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
- struct ccid *new_ccid;
-
- /* Check if nothing is being changed. */
- if (ccid_nr == new_ccid_nr)
- return 0;
-
- new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
- if (new_ccid == NULL)
- return -ENOMEM;
-
- if (rx) {
- ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
- dp->dccps_hc_rx_ccid = new_ccid;
- dmsk->dccpms_rx_ccid = new_ccid_nr;
- } else {
- ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
- dp->dccps_hc_tx_ccid = new_ccid;
- dmsk->dccpms_tx_ccid = new_ccid_nr;
- }
-
- return 0;
-}
-
-static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
-{
- dccp_feat_debug(type, feat, val);
-
- switch (feat) {
- case DCCPF_CCID:
- return dccp_feat_update_ccid(sk, type, val);
- default:
- dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
- dccp_feat_typename(type), feat);
- break;
- }
- return 0;
-}
-
/* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */
static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen)
{
return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len);
}
-#ifdef __this_is_the_old_framework_and_will_be_removed_later_in_a_subsequent_patch
-static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
- u8 *rpref, u8 rlen)
-{
- struct dccp_sock *dp = dccp_sk(sk);
- u8 *spref, slen, *res = NULL;
- int i, j, rc, agree = 1;
-
- BUG_ON(rpref == NULL);
-
- /* check if we are the black sheep */
- if (dp->dccps_role == DCCP_ROLE_CLIENT) {
- spref = rpref;
- slen = rlen;
- rpref = opt->dccpop_val;
- rlen = opt->dccpop_len;
- } else {
- spref = opt->dccpop_val;
- slen = opt->dccpop_len;
- }
- /*
- * Now we have server preference list in spref and client preference in
- * rpref
- */
- BUG_ON(spref == NULL);
- BUG_ON(rpref == NULL);
-
- /* FIXME sanity check vals */
-
- /* Are values in any order? XXX Lame "algorithm" here */
- for (i = 0; i < slen; i++) {
- for (j = 0; j < rlen; j++) {
- if (spref[i] == rpref[j]) {
- res = &spref[i];
- break;
- }
- }
- if (res)
- break;
- }
-
- /* we didn't agree on anything */
- if (res == NULL) {
- /* confirm previous value */
- switch (opt->dccpop_feat) {
- case DCCPF_CCID:
- /* XXX did i get this right? =P */
- if (opt->dccpop_type == DCCPO_CHANGE_L)
- res = &dccp_msk(sk)->dccpms_tx_ccid;
- else
- res = &dccp_msk(sk)->dccpms_rx_ccid;
- break;
-
- default:
- DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
- /* XXX implement res */
- return -EFAULT;
- }
-
- dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
- agree = 0; /* this is used for mandatory options... */
- }
-
- /* need to put result and our preference list */
- rlen = 1 + opt->dccpop_len;
- rpref = kmalloc(rlen, GFP_ATOMIC);
- if (rpref == NULL)
- return -ENOMEM;
-
- *rpref = *res;
- memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
-
- /* put it in the "confirm queue" */
- if (opt->dccpop_sc == NULL) {
- opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
- if (opt->dccpop_sc == NULL) {
- kfree(rpref);
- return -ENOMEM;
- }
- } else {
- /* recycle the confirm slot */
- BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
- kfree(opt->dccpop_sc->dccpoc_val);
- dccp_pr_debug("recycling confirm slot\n");
- }
- memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
-
- opt->dccpop_sc->dccpoc_val = rpref;
- opt->dccpop_sc->dccpoc_len = rlen;
-
- /* update the option on our side [we are about to send the confirm] */
- rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
- if (rc) {
- kfree(opt->dccpop_sc->dccpoc_val);
- kfree(opt->dccpop_sc);
- opt->dccpop_sc = NULL;
- return rc;
- }
-
- dccp_pr_debug("Will confirm %d\n", *rpref);
-
- /* say we want to change to X but we just got a confirm X, suppress our
- * change
- */
- if (!opt->dccpop_conf) {
- if (*opt->dccpop_val == *res)
- opt->dccpop_conf = 1;
- dccp_pr_debug("won't ask for change of same feature\n");
- }
-
- return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
-}
-
-static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
-{
- struct dccp_minisock *dmsk = dccp_msk(sk);
- struct dccp_opt_pend *opt;
- int rc = 1;
- u8 t;
-
- /*
- * We received a CHANGE. We gotta match it against our own preference
- * list. If we got a CHANGE_R it means it's a change for us, so we need
- * to compare our CHANGE_L list.
- */
- if (type == DCCPO_CHANGE_L)
- t = DCCPO_CHANGE_R;
- else
- t = DCCPO_CHANGE_L;
-
- /* find our preference list for this feature */
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (opt->dccpop_type != t || opt->dccpop_feat != feature)
- continue;
-
- /* find the winner from the two preference lists */
- rc = dccp_feat_reconcile(sk, opt, val, len);
- break;
- }
-
- /* We didn't deal with the change. This can happen if we have no
- * preference list for the feature. In fact, it just shouldn't
- * happen---if we understand a feature, we should have a preference list
- * with at least the default value.
- */
- BUG_ON(rc == 1);
-
- return rc;
-}
-
-static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
-{
- struct dccp_opt_pend *opt;
- struct dccp_minisock *dmsk = dccp_msk(sk);
- u8 *copy;
- int rc;
-
- /* NN features must be Change L (sec. 6.3.2) */
- if (type != DCCPO_CHANGE_L) {
- dccp_pr_debug("received %s for NN feature %d\n",
- dccp_feat_typename(type), feature);
- return -EFAULT;
- }
-
- /* XXX sanity check opt val */
-
- /* copy option so we can confirm it */
- opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
- if (opt == NULL)
- return -ENOMEM;
-
- copy = kmemdup(val, len, GFP_ATOMIC);
- if (copy == NULL) {
- kfree(opt);
- return -ENOMEM;
- }
-
- opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
- opt->dccpop_feat = feature;
- opt->dccpop_val = copy;
- opt->dccpop_len = len;
-
- /* change feature */
- rc = dccp_feat_update(sk, type, feature, *val);
- if (rc) {
- kfree(opt->dccpop_val);
- kfree(opt);
- return rc;
- }
-
- dccp_feat_debug(type, feature, *copy);
-
- list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
-
- return 0;
-}
-
-static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
- u8 type, u8 feature)
-{
- /* XXX check if other confirms for that are queued and recycle slot */
- struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
-
- if (opt == NULL) {
- /* XXX what do we do? Ignoring should be fine. It's a change
- * after all =P
- */
- return;
- }
-
- switch (type) {
- case DCCPO_CHANGE_L:
- opt->dccpop_type = DCCPO_CONFIRM_R;
- break;
- case DCCPO_CHANGE_R:
- opt->dccpop_type = DCCPO_CONFIRM_L;
- break;
- default:
- DCCP_WARN("invalid type %d\n", type);
- kfree(opt);
- return;
- }
- opt->dccpop_feat = feature;
- opt->dccpop_val = NULL;
- opt->dccpop_len = 0;
-
- /* change feature */
- dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
-
- list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
-}
-
-static void dccp_feat_flush_confirm(struct sock *sk)
-{
- struct dccp_minisock *dmsk = dccp_msk(sk);
- /* Check if there is anything to confirm in the first place */
- int yes = !list_empty(&dmsk->dccpms_conf);
-
- if (!yes) {
- struct dccp_opt_pend *opt;
-
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (opt->dccpop_conf) {
- yes = 1;
- break;
- }
- }
- }
-
- if (!yes)
- return;
-
- /* OK there is something to confirm... */
- /* XXX check if packet is in flight? Send delayed ack?? */
- if (sk->sk_state == DCCP_OPEN)
- dccp_send_ack(sk);
-}
-
-int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
-{
- int rc;
-
- /* Ignore Change requests other than during connection setup */
- if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
- return 0;
- dccp_feat_debug(type, feature, *val);
-
- /* figure out if it's SP or NN feature */
- switch (feature) {
- /* deal with SP features */
- case DCCPF_CCID:
- /* XXX Obsoleted by next patch
- rc = dccp_feat_sp(sk, type, feature, val, len); */
- break;
-
- /* deal with NN features */
- case DCCPF_ACK_RATIO:
- /* XXX Obsoleted by next patch
- rc = dccp_feat_nn(sk, type, feature, val, len); */
- break;
-
- /* XXX implement other features */
- default:
- dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
- dccp_feat_typename(type), feature);
- rc = -EFAULT;
- break;
- }
-
- /* check if there were problems changing features */
- if (rc) {
- /* If we don't agree on SP, we sent a confirm for old value.
- * However we propagate rc to caller in case option was
- * mandatory
- */
- if (rc != DCCP_FEAT_SP_NOAGREE)
- dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
- }
-
- /* generate the confirm [if required] */
- dccp_feat_flush_confirm(sk);
-
- return rc;
-}
-
-EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
-
-int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
- u8 *val, u8 len)
-{
- u8 t;
- struct dccp_opt_pend *opt;
- struct dccp_minisock *dmsk = dccp_msk(sk);
- int found = 0;
- int all_confirmed = 1;
-
- /* Ignore Confirm options other than during connection setup */
- if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
- return 0;
- dccp_feat_debug(type, feature, *val);
-
- /* locate our change request */
- switch (type) {
- case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
- case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
- default: DCCP_WARN("invalid type %d\n", type);
- return 1;
-
- }
- /* XXX sanity check feature value */
-
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (!opt->dccpop_conf && opt->dccpop_type == t &&
- opt->dccpop_feat == feature) {
- found = 1;
- dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
-
- /* XXX do sanity check */
-
- opt->dccpop_conf = 1;
-
- /* We got a confirmation---change the option */
- dccp_feat_update(sk, opt->dccpop_type,
- opt->dccpop_feat, *val);
-
- /* XXX check the return value of dccp_feat_update */
- break;
- }
-
- if (!opt->dccpop_conf)
- all_confirmed = 0;
- }
-
- if (!found)
- dccp_pr_debug("%s(%d, ...) never requested\n",
- dccp_feat_typename(type), feature);
- return 0;
-}
-
-EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
-#endif /* (later) */
-
-void dccp_feat_clean(struct dccp_minisock *dmsk)
-{
- struct dccp_opt_pend *opt, *next;
-
- list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
- dccpop_node) {
- BUG_ON(opt->dccpop_val == NULL);
- kfree(opt->dccpop_val);
-
- if (opt->dccpop_sc != NULL) {
- BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
- kfree(opt->dccpop_sc->dccpoc_val);
- kfree(opt->dccpop_sc);
- }
-
- kfree(opt);
- }
- INIT_LIST_HEAD(&dmsk->dccpms_pending);
-
- list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
- BUG_ON(opt == NULL);
- if (opt->dccpop_val != NULL)
- kfree(opt->dccpop_val);
- kfree(opt);
- }
- INIT_LIST_HEAD(&dmsk->dccpms_conf);
-}
-
-EXPORT_SYMBOL_GPL(dccp_feat_clean);
-
-/* this is to be called only when a listening sock creates its child. It is
- * assumed by the function---the confirm is not duplicated, but rather it is
- * "passed on".
- */
-int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
-{
- struct dccp_minisock *olddmsk = dccp_msk(oldsk);
- struct dccp_minisock *newdmsk = dccp_msk(newsk);
- struct dccp_opt_pend *opt;
- int rc = 0;
-
- INIT_LIST_HEAD(&newdmsk->dccpms_pending);
- INIT_LIST_HEAD(&newdmsk->dccpms_conf);
-
- list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
- struct dccp_opt_pend *newopt;
- /* copy the value of the option */
- u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
-
- if (val == NULL)
- goto out_clean;
-
- newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
- if (newopt == NULL) {
- kfree(val);
- goto out_clean;
- }
-
- /* insert the option */
- newopt->dccpop_val = val;
- list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
-
- /* XXX what happens with backlogs and multiple connections at
- * once...
- */
- /* the master socket no longer needs to worry about confirms */
- opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
-
- /* reset state for a new socket */
- opt->dccpop_conf = 0;
- }
-
- /* XXX not doing anything about the conf queue */
-
-out:
- return rc;
-
-out_clean:
- dccp_feat_clean(newdmsk);
- rc = -ENOMEM;
- goto out;
-}
-
-EXPORT_SYMBOL_GPL(dccp_feat_clone);
-
/**
* dccp_feat_change_recv - Process incoming ChangeL/R options
* @fn: feature-negotiation list to update
git://bbs.cooldavid.org / net-next-2.6.git / commitdiff