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Commit 86349c8d authored by Gerrit Renker's avatar Gerrit Renker
Browse files

dccp: Registration routines for changing feature values 



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: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
parent 5591d286

net/dccp/ccids/ccid2.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

net/dccp/feat.c

+100 −23
Original line number Diff line number Diff line
@@ -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,

	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,

	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;

}

net/dccp/feat.h

+24 −1
Original line number Diff line number Diff line
@@ -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 */

net/dccp/proto.c

+1 −1
Original line number Diff line number Diff line
@@ -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;