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dccp: Registration routines for changing feature values

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Two registration routines, for SP and NN features, are provided by this patch,
replacing a previous routine which was used for both feature types.

These are internal-only routines and therefore start with `__feat_register'.

It further exports the known limits of Sequence Window and Ack Ratio as symbolic
constants.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This commit is contained in:
Gerrit Renker 2008-09-04 07:30:19 +02:00
parent 5591d28628
commit 86349c8d9c
4 changed files with 128 additions and 28 deletions
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6
net/dccp/ccids/ccid2.c
View file

@ -25,7 +25,7 @@
/*
* This implementation should follow RFC 4341
*/
#include "../feat.h"
#include "../ccid.h"
#include "../dccp.h"
#include "ccid2.h"
@ -147,8 +147,8 @@ static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
val = max_ratio;
}
if (val > 0xFFFF) /* RFC 4340, 11.3 */
val = 0xFFFF;
if (val > DCCPF_ACK_RATIO_MAX)
val = DCCPF_ACK_RATIO_MAX;
if (val == dp->dccps_l_ack_ratio)
return;

123
net/dccp/feat.c
View file

@ -300,6 +300,95 @@ int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
return -ENOMEM;
}
static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
{
switch (feat_num) {
case DCCPF_ACK_RATIO:
return val <= DCCPF_ACK_RATIO_MAX;
case DCCPF_SEQUENCE_WINDOW:
return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX;
}
return 0; /* feature unknown - so we can't tell */
}
/* check that SP values are within the ranges defined in RFC 4340 */
static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val)
{
switch (feat_num) {
case DCCPF_CCID:
return val == DCCPC_CCID2 || val == DCCPC_CCID3;
/* Type-check Boolean feature values: */
case DCCPF_SHORT_SEQNOS:
case DCCPF_ECN_INCAPABLE:
case DCCPF_SEND_ACK_VECTOR:
case DCCPF_SEND_NDP_COUNT:
case DCCPF_DATA_CHECKSUM:
case DCCPF_SEND_LEV_RATE:
return val < 2;
case DCCPF_MIN_CSUM_COVER:
return val < 16;
}
return 0; /* feature unknown */
}
static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
{
if (sp_list == NULL || sp_len < 1)
return 0;
while (sp_len--)
if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++))
return 0;
return 1;
}
/**
* __feat_register_nn - Register new NN value on socket
* @fn: feature-negotiation list to register with
* @feat: an NN feature from %dccp_feature_numbers
* @mandatory: use Mandatory option if 1
* @nn_val: value to register (restricted to 4 bytes)
* Note that NN features are local by definition (RFC 4340, 6.3.2).
*/
static int __feat_register_nn(struct list_head *fn, u8 feat,
u8 mandatory, u64 nn_val)
{
dccp_feat_val fval = { .nn = nn_val };
if (dccp_feat_type(feat) != FEAT_NN ||
!dccp_feat_is_valid_nn_val(feat, nn_val))
return -EINVAL;
/* Don't bother with default values, they will be activated anyway. */
if (nn_val - (u64)dccp_feat_default_value(feat) == 0)
return 0;
return dccp_feat_push_change(fn, feat, 1, mandatory, &fval);
}
/**
* __feat_register_sp - Register new SP value/list on socket
* @fn: feature-negotiation list to register with
* @feat: an SP feature from %dccp_feature_numbers
* @is_local: whether the local (1) or the remote (0) @feat is meant
* @mandatory: use Mandatory option if 1
* @sp_val: SP value followed by optional preference list
* @sp_len: length of @sp_val in bytes
*/
static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
u8 mandatory, u8 const *sp_val, u8 sp_len)
{
dccp_feat_val fval;
if (dccp_feat_type(feat) != FEAT_SP ||
!dccp_feat_sp_list_ok(feat, sp_val, sp_len))
return -EINVAL;
if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
return -ENOMEM;
return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
}
int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
u8 *val, u8 len, gfp_t gfp)
{
@ -836,42 +925,30 @@ int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
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 dccp_feat_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_minisock *dmsk = dccp_msk(sk);
int rc;
INIT_LIST_HEAD(&dmsk->dccpms_pending);
INIT_LIST_HEAD(&dmsk->dccpms_conf);
INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */
INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */
/* CCID L */
rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
&dmsk->dccpms_tx_ccid, 1);
rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
&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);
rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
&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);
rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
dmsk->dccpms_ack_ratio);
out:
return rc;
}

25
net/dccp/feat.h
View file

@ -14,6 +14,15 @@
#include <linux/types.h>
#include "dccp.h"
/*
* Known limit values
*/
/* Ack Ratio takes 2-byte integer values (11.3) */
#define DCCPF_ACK_RATIO_MAX 0xFFFF
/* Wmin=32 and Wmax=2^46-1 from 7.5.2 */
#define DCCPF_SEQ_WMIN 32
#define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull
enum dccp_feat_type {
FEAT_AT_RX = 1, /* located at RX side of half-connection */
FEAT_AT_TX = 2, /* located at TX side of half-connection */
@ -74,6 +83,20 @@ static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry)
return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R;
}
/**
* struct ccid_dependency - Track changes resulting from choosing a CCID
* @dependent_feat: one of %dccp_feature_numbers
* @is_local: local (1) or remote (0) @dependent_feat
* @is_mandatory: whether presence of @dependent_feat is mission-critical or not
* @val: corresponding default value for @dependent_feat (u8 is sufficient here)
*/
struct ccid_dependency {
u8 dependent_feat;
bool is_local:1,
is_mandatory:1;
u8 val;
};
#ifdef CONFIG_IP_DCCP_DEBUG
extern const char *dccp_feat_typename(const u8 type);
extern const char *dccp_feat_name(const u8 feat);
@ -96,6 +119,6 @@ extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
extern void dccp_feat_clean(struct dccp_minisock *dmsk);
extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
extern int dccp_feat_init(struct dccp_minisock *dmsk);
extern int dccp_feat_init(struct sock *sk);
#endif /* _DCCP_FEAT_H */

2
net/dccp/proto.c
View file

@ -202,7 +202,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
* setsockopt(CCIDs-I-want/accept). -acme
*/
if (likely(ctl_sock_initialized)) {
int rc = dccp_feat_init(dmsk);
int rc = dccp_feat_init(sk);
if (rc)
return rc;