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Commit 75757a7d authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

dccp: Preference list reconciliation 



This provides two functions to
 * reconcile preference lists (with appropriate return codes) and
 * reorder the preference list if successful reconciliation changed the
   preferred value.

The patch also removes the old code for processing SP/NN Change options, since
new code to process these is mostly there already; related references have been
commented out.

The code for processing Change options follows in the next patch.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8b7b6c75

net/dccp/feat.c

+75 −2
Original line number Original line Diff line number Diff line
@@ -690,6 +690,76 @@ static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) 
	return 0;

	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)

{

	u8 c, s;



	for (s = 0; s < slen; s++)

		for (c = 0; c < clen; c++)

			if (servlist[s] == clilist[c])

				return servlist[s];

	return -1;

}



/**

 * dccp_feat_prefer  -  Move preferred entry to the start of array

 * Reorder the @array_len elements in @array so that @preferred_value comes

 * first. Returns >0 to indicate that @preferred_value does occur in @array.

 */

static u8 dccp_feat_prefer(u8 preferred_value, u8 *array, u8 array_len)

{

	u8 i, does_occur = 0;



	if (array != NULL) {

		for (i = 0; i < array_len; i++)

			if (array[i] == preferred_value) {

				array[i] = array[0];

				does_occur++;

			}

		if (does_occur)

			array[0] = preferred_value;

	}

	return does_occur;

}



/**

 * dccp_feat_reconcile  -  Reconcile SP preference lists

 *  @fval: SP list to reconcile into

 *  @arr: received SP preference list

 *  @len: length of @arr in bytes

 *  @is_server: whether this side is the server (and @fv is the server's list)

 *  @reorder: whether to reorder the list in @fv after reconciling with @arr

 * When successful, > 0 is returned and the reconciled list is in @fval.

 * A value of 0 means that negotiation failed (no shared entry).

 */

static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len,

			       bool is_server, bool reorder)

{

	int rc;



	if (!fv->sp.vec || !arr) {

		DCCP_CRIT("NULL feature value or array");

		return 0;

	}



	if (is_server)

		rc = dccp_feat_preflist_match(fv->sp.vec, fv->sp.len, arr, len);

	else

		rc = dccp_feat_preflist_match(arr, len, fv->sp.vec, fv->sp.len);



	if (!reorder)

		return rc;

	if (rc < 0)

		return 0;



	/*

	 * Reorder list: used for activating features and in dccp_insert_fn_opt.

	 */

	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,

static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,

			       u8 *rpref, u8 rlen)

			       u8 *rpref, u8 rlen)

{

{
@@ -885,6 +955,7 @@ static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 




	return 0;

	return 0;

}

}

#endif /* (later) */





static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,

static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,

				    u8 type, u8 feature)

				    u8 type, u8 feature)
@@ -960,12 +1031,14 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 
	switch (feature) {

	switch (feature) {

	/* deal with SP features */

	/* deal with SP features */

	case DCCPF_CCID:

	case DCCPF_CCID:

		rc = dccp_feat_sp(sk, type, feature, val, len);

		/* XXX Obsoleted by next patch

		rc = dccp_feat_sp(sk, type, feature, val, len); */

		break;

		break;





	/* deal with NN features */

	/* deal with NN features */

	case DCCPF_ACK_RATIO:

	case DCCPF_ACK_RATIO:

		rc = dccp_feat_nn(sk, type, feature, val, len);

		/* XXX Obsoleted by next patch

		rc = dccp_feat_nn(sk, type, feature, val, len); */

		break;

		break;





	/* XXX implement other features */

	/* XXX implement other features */