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Commit af3b867e authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

[DCCP]: Support inserting options during the 3-way handshake 



This provides a separate routine to insert options during the initial handshake.
The main purpose is to conduct feature negotiation, for the moment the only user
is the timestamp echo needed for the (CCID3) handshake RTT sample.

Padding of options has been put into a small separate routine, to be shared among
the two functions. This could also be used as a generic routine to finish inserting
options.

Also removed an `XXX' comment since its content was obvious.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b4d4f7c7

net/dccp/dccp.h

+1 −0
Original line number Diff line number Diff line
@@ -428,6 +428,7 @@ static inline int dccp_ack_pending(const struct sock *sk) 
}



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

extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);

extern int dccp_insert_option_elapsed_time(struct sock *sk,

					    struct sk_buff *skb,

					    u32 elapsed_time);

net/dccp/options.c

+22 −10
Original line number Diff line number Diff line
@@ -537,6 +537,18 @@ static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) 
	return 0;

}



/* The length of all options needs to be a multiple of 4 (5.8) */

static void dccp_insert_option_padding(struct sk_buff *skb)

{

	int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;



	if (padding != 0) {

		padding = 4 - padding;

		memset(skb_push(skb, padding), 0, padding);

		DCCP_SKB_CB(skb)->dccpd_opt_len += padding;

	}

}



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

{

	struct dccp_sock *dp = dccp_sk(sk);
@@ -580,18 +592,18 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb) 
	    dccp_insert_option_timestamp_echo(dp, NULL, skb))

		return -1;



	/* XXX: insert other options when appropriate */

	dccp_insert_option_padding(skb);

	return 0;

}



	if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {

		/* The length of all options has to be a multiple of 4 */

		int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;

int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)

{

	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;



		if (padding != 0) {

			padding = 4 - padding;

			memset(skb_push(skb, padding), 0, padding);

			DCCP_SKB_CB(skb)->dccpd_opt_len += padding;

		}

	}

	if (dreq->dreq_timestamp_echo != 0 &&

	    dccp_insert_option_timestamp_echo(NULL, dreq, skb))

		return -1;



	dccp_insert_option_padding(skb);

	return 0;

}

net/dccp/output.c

+1 −1
Original line number Diff line number Diff line
@@ -303,7 +303,7 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, 
	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;

	DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_iss;



	if (dccp_insert_options(sk, skb)) {

	if (dccp_insert_options_rsk(dreq, skb)) {

		kfree_skb(skb);

		return NULL;

	}