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authorAndrea Bittau <a.bittau@cs.ucl.ac.uk>2006-03-20 17:43:56 -0800
committerDavid S. Miller <davem@davemloft.net>2006-03-20 17:43:56 -0800
commitafe00251dd9b53d51de91ff0099961f42bbf3754 (patch)
treea56aa987140662cf3e6e65be402b8591298c5ced /net/dccp/feat.c
parent2a91aa3967398fb94eccc8da67c82bce9f67afdf (diff)
[DCCP]: Initial feature negotiation implementation
Still needs more work, but boots and doesn't crashes, even does some negotiation! 18:38:52.174934 127.0.0.1.43458 > 127.0.0.1.5001: request <change_l ack_ratio 2, change_r ccid 2, change_l ccid 2> 18:38:52.218526 127.0.0.1.5001 > 127.0.0.1.43458: response <nop, nop, change_l ack_ratio 2, confirm_r ccid 2 2, confirm_l ccid 2 2, confirm_r ack_ratio 2> 18:38:52.185398 127.0.0.1.43458 > 127.0.0.1.5001: <nop, confirm_r ack_ratio 2, ack_vector0 0x00, elapsed_time 212> :-) Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/feat.c')
-rw-r--r--net/dccp/feat.c554
1 files changed, 554 insertions, 0 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
new file mode 100644
index 000000000000..99d7b7f9efa9
--- /dev/null
+++ b/net/dccp/feat.c
@@ -0,0 +1,554 @@
+/*
+ * net/dccp/feat.c
+ *
+ * An implementation of the DCCP protocol
+ * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include "dccp.h"
+#include "feat.h"
+
+#define DCCP_FEAT_SP_NOAGREE (-123)
+
+int dccp_feat_change(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len,
+ gfp_t gfp)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct dccp_opt_pend *opt;
+
+ dccp_pr_debug("feat change type=%d feat=%d\n", type, feature);
+
+ /* check if that feature is already being negotiated */
+ list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
+ dccpop_node) {
+ /* ok we found a negotiation for this option already */
+ if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
+ dccp_pr_debug("Replacing old\n");
+ /* replace */
+ BUG_ON(opt->dccpop_val == NULL);
+ kfree(opt->dccpop_val);
+ opt->dccpop_val = val;
+ opt->dccpop_len = len;
+ opt->dccpop_conf = 0;
+ return 0;
+ }
+ }
+
+ /* negotiation for a new feature */
+ opt = kmalloc(sizeof(*opt), gfp);
+ if (opt == NULL)
+ return -ENOMEM;
+
+ opt->dccpop_type = type;
+ opt->dccpop_feat = feature;
+ opt->dccpop_len = len;
+ opt->dccpop_val = val;
+ opt->dccpop_conf = 0;
+ opt->dccpop_sc = NULL;
+
+ BUG_ON(opt->dccpop_val == NULL);
+
+ list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_pending);
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_change);
+
+/* XXX taking only u8 vals */
+static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
+{
+ /* FIXME implement */
+ dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val);
+ return 0;
+}
+
+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 */
+ /* XXX assume values are 1 byte */
+ 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 = &dp->dccps_options.dccpo_tx_ccid;
+ else
+ res = &dp->dccps_options.dccpo_rx_ccid;
+ break;
+
+ default:
+ WARN_ON(1); /* 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 */
+ /* XXX assume 1 byte vals */
+ 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 = 0;
+ 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_sock *dp = dccp_sk(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, &dp->dccps_options.dccpo_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_sock *dp = dccp_sk(sk);
+ u8 *copy;
+ int rc;
+
+ /* NN features must be change L */
+ if (type == DCCPO_CHANGE_R) {
+ dccp_pr_debug("received CHANGE_R %d for NN feat %d\n",
+ 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 = kmalloc(len, GFP_ATOMIC);
+ if (copy == NULL) {
+ kfree(opt);
+ return -ENOMEM;
+ }
+ memcpy(copy, val, len);
+
+ 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_pr_debug("Confirming NN feature %d (val=%d)\n", feature, *copy);
+ list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf);
+
+ return 0;
+}
+
+static void dccp_feat_empty_confirm(struct sock *sk, u8 type, u8 feature)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ /* 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;
+ }
+
+ opt->dccpop_type = type == DCCPO_CHANGE_L ? DCCPO_CONFIRM_R :
+ DCCPO_CONFIRM_L;
+ opt->dccpop_feat = feature;
+ opt->dccpop_val = 0;
+ opt->dccpop_len = 0;
+
+ /* change feature */
+ dccp_pr_debug("Empty confirm feature %d type %d\n", feature, type);
+ list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf);
+}
+
+static void dccp_feat_flush_confirm(struct sock *sk)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ /* Check if there is anything to confirm in the first place */
+ int yes = !list_empty(&dp->dccps_options.dccpo_conf);
+
+ if (!yes) {
+ struct dccp_opt_pend *opt;
+
+ list_for_each_entry(opt, &dp->dccps_options.dccpo_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;
+
+ dccp_pr_debug("got feat change type=%d feat=%d\n", type, feature);
+
+ /* figure out if it's SP or NN feature */
+ switch (feature) {
+ /* deal with SP features */
+ case DCCPF_CCID:
+ rc = dccp_feat_sp(sk, type, feature, val, len);
+ break;
+
+ /* deal with NN features */
+ case DCCPF_ACK_RATIO:
+ rc = dccp_feat_nn(sk, type, feature, val, len);
+ break;
+
+ /* XXX implement other features */
+ default:
+ 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(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_sock *dp = dccp_sk(sk);
+ int rc = 1;
+ int all_confirmed = 1;
+
+ dccp_pr_debug("got feat confirm type=%d feat=%d\n", type, feature);
+
+ /* XXX sanity check type & feat */
+
+ /* locate our change request */
+ t = type == DCCPO_CONFIRM_L ? DCCPO_CHANGE_R : DCCPO_CHANGE_L;
+
+ list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
+ dccpop_node) {
+ if (!opt->dccpop_conf && opt->dccpop_type == t &&
+ opt->dccpop_feat == feature) {
+ /* we found it */
+ /* 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);
+
+ dccp_pr_debug("feat %d type %d confirmed %d\n",
+ feature, type, *val);
+ rc = 0;
+ break;
+ }
+
+ if (!opt->dccpop_conf)
+ all_confirmed = 0;
+ }
+
+ /* fix re-transmit timer */
+ /* XXX gotta make sure that no option negotiation occurs during
+ * connection shutdown. Consider that the CLOSEREQ is sent and timer is
+ * on. if all options are confirmed it might kill timer which should
+ * remain alive until close is received.
+ */
+ if (all_confirmed) {
+ dccp_pr_debug("clear feat negotiation timer %p\n", sk);
+ inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
+ }
+
+ if (rc)
+ dccp_pr_debug("feat %d type %d never requested\n",
+ feature, type);
+ return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
+
+void dccp_feat_clean(struct sock *sk)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct dccp_opt_pend *opt, *next;
+
+ list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_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(&dp->dccps_options.dccpo_pending);
+
+ list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_conf,
+ dccpop_node) {
+ BUG_ON(opt == NULL);
+ if (opt->dccpop_val != NULL)
+ kfree(opt->dccpop_val);
+ kfree(opt);
+ }
+ INIT_LIST_HEAD(&dp->dccps_options.dccpo_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_sock *olddp = dccp_sk(oldsk);
+ struct dccp_sock *newdp = dccp_sk(newsk);
+ struct dccp_opt_pend *opt;
+ int rc = 0;
+
+ INIT_LIST_HEAD(&newdp->dccps_options.dccpo_pending);
+ INIT_LIST_HEAD(&newdp->dccps_options.dccpo_conf);
+
+ list_for_each_entry(opt, &olddp->dccps_options.dccpo_pending,
+ dccpop_node) {
+ struct dccp_opt_pend *newopt;
+ /* copy the value of the option */
+ u8 *val = kmalloc(opt->dccpop_len, GFP_ATOMIC);
+
+ if (val == NULL)
+ goto out_clean;
+ memcpy(val, opt->dccpop_val, opt->dccpop_len);
+
+ newopt = kmalloc(sizeof(*newopt), GFP_ATOMIC);
+ if (newopt == NULL) {
+ kfree(val);
+ goto out_clean;
+ }
+
+ /* insert the option */
+ memcpy(newopt, opt, sizeof(*newopt));
+ newopt->dccpop_val = val;
+ list_add_tail(&newopt->dccpop_node,
+ &newdp->dccps_options.dccpo_pending);
+
+ /* XXX what happens with backlogs and multiple connections at
+ * once...
+ */
+ /* the master socket no longer needs to worry about confirms */
+ opt->dccpop_sc = 0; /* 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(newsk);
+ rc = -ENOMEM;
+ goto out;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_clone);
+
+static int __dccp_feat_init(struct sock *sk, u8 type, u8 feat, u8 *val, u8 len)
+{
+ int rc = -ENOMEM;
+ u8 *copy = kmalloc(len, GFP_KERNEL);
+
+ if (copy != NULL) {
+ memcpy(copy, val, len);
+ rc = dccp_feat_change(sk, type, feat, copy, len, GFP_KERNEL);
+ if (rc)
+ kfree(copy);
+ }
+ return rc;
+}
+
+int dccp_feat_init(struct sock *sk)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ int rc;
+
+ INIT_LIST_HEAD(&dp->dccps_options.dccpo_pending);
+ INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf);
+
+ /* CCID L */
+ rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_CCID,
+ &dp->dccps_options.dccpo_tx_ccid, 1);
+ if (rc)
+ goto out;
+
+ /* CCID R */
+ rc = __dccp_feat_init(sk, DCCPO_CHANGE_R, DCCPF_CCID,
+ &dp->dccps_options.dccpo_rx_ccid, 1);
+ if (rc)
+ goto out;
+
+ /* Ack ratio */
+ rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
+ &dp->dccps_options.dccpo_ack_ratio, 1);
+out:
+ return rc;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_init);

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