/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- dccp_feat_change
- dccp_feat_update_ccid
- dccp_feat_update
- dccp_feat_reconcile
- dccp_feat_sp
- dccp_feat_nn
- dccp_feat_empty_confirm
- dccp_feat_flush_confirm
- dccp_feat_change_recv
- dccp_feat_confirm_recv
- dccp_feat_clean
- dccp_feat_clone
- __dccp_feat_init
- dccp_feat_init
- dccp_feat_typename
- dccp_feat_name
/*
* net/dccp/feat.c
*
* An implementation of the DCCP protocol
* Andrea Bittau <a.bittau@cs.ucl.ac.uk>
*
* ASSUMPTIONS
* -----------
* o All currently known SP features have 1-byte quantities. If in the future
* extensions of RFCs 4340..42 define features with item lengths larger than
* one byte, a feature-specific extension of the code will be required.
*
* 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/module.h>
#include "ccid.h"
#include "feat.h"
#define DCCP_FEAT_SP_NOAGREE (-123)
int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
u8 *val, u8 len, gfp_t gfp)
{
struct dccp_opt_pend *opt;
dccp_feat_debug(type, feature, *val);
if (len > 3) {
DCCP_WARN("invalid length %d\n", len);
return -EINVAL;
}
/* XXX add further sanity checks */
/* check if that feature is already being negotiated */
list_for_each_entry(opt, &dmsk->dccpms_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, &dmsk->dccpms_pending);
return 0;
}
EXPORT_SYMBOL_GPL(dccp_feat_change);
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;
}
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;
dccp_feat_debug(type, feature, *val);
/* 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:
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;
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;
}
/* 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 (!found)
dccp_pr_debug("%s(%d, ...) never requested\n",
dccp_feat_typename(type), feature);
return 0;
}
EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
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);
static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
u8 *val, u8 len)
{
int rc = -ENOMEM;
u8 *copy = kmemdup(val, len, GFP_KERNEL);
if (copy != NULL) {
rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
if (rc)
kfree(copy);
}
return rc;
}
int dccp_feat_init(struct dccp_minisock *dmsk)
{
int rc;
INIT_LIST_HEAD(&dmsk->dccpms_pending);
INIT_LIST_HEAD(&dmsk->dccpms_conf);
/* CCID L */
rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
&dmsk->dccpms_tx_ccid, 1);
if (rc)
goto out;
/* CCID R */
rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
&dmsk->dccpms_rx_ccid, 1);
if (rc)
goto out;
/* Ack ratio */
rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
&dmsk->dccpms_ack_ratio, 1);
out:
return rc;
}
EXPORT_SYMBOL_GPL(dccp_feat_init);
#ifdef CONFIG_IP_DCCP_DEBUG
const char *dccp_feat_typename(const u8 type)
{
switch(type) {
case DCCPO_CHANGE_L: return("ChangeL");
case DCCPO_CONFIRM_L: return("ConfirmL");
case DCCPO_CHANGE_R: return("ChangeR");
case DCCPO_CONFIRM_R: return("ConfirmR");
/* the following case must not appear in feature negotation */
default: dccp_pr_debug("unknown type %d [BUG!]\n", type);
}
return NULL;
}
EXPORT_SYMBOL_GPL(dccp_feat_typename);
const char *dccp_feat_name(const u8 feat)
{
static const char *feature_names[] = {
[DCCPF_RESERVED] = "Reserved",
[DCCPF_CCID] = "CCID",
[DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos",
[DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
[DCCPF_ECN_INCAPABLE] = "ECN Incapable",
[DCCPF_ACK_RATIO] = "Ack Ratio",
[DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
[DCCPF_SEND_NDP_COUNT] = "Send NDP Count",
[DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage",
[DCCPF_DATA_CHECKSUM] = "Send Data Checksum",
};
if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
return feature_names[DCCPF_RESERVED];
if (feat >= DCCPF_MIN_CCID_SPECIFIC)
return "CCID-specific";
return feature_names[feat];
}
EXPORT_SYMBOL_GPL(dccp_feat_name);
#endif /* CONFIG_IP_DCCP_DEBUG */