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Commit 0ef118a0 authored by Gerrit Renker's avatar Gerrit Renker
Browse files

dccp: Insert feature-negotiation options into skb 



This patch replaces the earlier insertion routine from options.c, so that
code specific to feature negotiation can remain in feat.c. This is possible
by calling a function already existing in options.c.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
parent cf9ddf73

net/dccp/dccp.h

+2 −0
Original line number Diff line number Diff line
@@ -443,6 +443,8 @@ static inline int dccp_ack_pending(const struct sock *sk) 


extern int  dccp_feat_finalise_settings(struct dccp_sock *dp);

extern int  dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);

extern int  dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,

				  struct sk_buff *skb);

extern void dccp_feat_list_purge(struct list_head *fn_list);



extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);

net/dccp/feat.c

+65 −0
Original line number Diff line number Diff line
@@ -300,6 +300,20 @@ int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) 
	return -ENOMEM;

}



/**

 * dccp_feat_valid_nn_length  -  Enforce length constraints on NN options

 * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only,

 * incoming options are accepted as long as their values are valid.

 */

static u8 dccp_feat_valid_nn_length(u8 feat_num)

{

	if (feat_num == DCCPF_ACK_RATIO)	/* RFC 4340, 11.3 and 6.6.8 */

		return 2;

	if (feat_num == DCCPF_SEQUENCE_WINDOW)	/* RFC 4340, 7.5.2 and 6.5  */

		return 6;

	return 0;

}



static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)

{

	switch (feat_num) {
@@ -341,6 +355,57 @@ static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) 
	return 1;

}



/**

 * dccp_feat_insert_opts  -  Generate FN options from current list state

 * @skb: next sk_buff to be sent to the peer

 * @dp: for client during handshake and general negotiation

 * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND)

 */

int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq,

			  struct sk_buff *skb)

{

	struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;

	struct dccp_feat_entry *pos, *next;

	u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN];

	bool rpt;



	/* put entries into @skb in the order they appear in the list */

	list_for_each_entry_safe_reverse(pos, next, fn, node) {

		opt  = dccp_feat_genopt(pos);

		type = dccp_feat_type(pos->feat_num);

		rpt  = false;



		if (pos->empty_confirm) {

			len = 0;

			ptr = NULL;

		} else {

			if (type == FEAT_SP) {

				len = pos->val.sp.len;

				ptr = pos->val.sp.vec;

				rpt = pos->needs_confirm;

			} else if (type == FEAT_NN) {

				len = dccp_feat_valid_nn_length(pos->feat_num);

				ptr = nn_in_nbo;

				dccp_encode_value_var(pos->val.nn, ptr, len);

			} else {

				DCCP_BUG("unknown feature %u", pos->feat_num);

				return -1;

			}

		}



		if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt))

			return -1;

		if (pos->needs_mandatory && dccp_insert_option_mandatory(skb))

			return -1;

		/*

		 * Enter CHANGING after transmitting the Change option (6.6.2).

		 */

		if (pos->state == FEAT_INITIALISING)

			pos->state = FEAT_CHANGING;

	}

	return 0;

}



/**

 * __feat_register_nn  -  Register new NN value on socket

 * @fn: feature-negotiation list to register with