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Commit d1935942 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP]: Extract tcp_match_queue_to_sack from sacktag code 



This is necessary for upcoming DSACK bugfix. Reduces sacktag
length which is not very sad thing at all... :-)

Notice that there's a need to handle out-of-mem at caller's
place.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f6fb128d

net/ipv4/tcp_input.c

+35 −19
Original line number Diff line number Diff line
@@ -1181,6 +1181,38 @@ static int tcp_check_dsack(struct tcp_sock *tp, struct sk_buff *ack_skb, 
	return dup_sack;

}



/* Check if skb is fully within the SACK block. In presence of GSO skbs,

 * the incoming SACK may not exactly match but we can find smaller MSS

 * aligned portion of it that matches. Therefore we might need to fragment

 * which may fail and creates some hassle (caller must handle error case

 * returns).

 */

int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,

			  u32 start_seq, u32 end_seq)

{

	int in_sack, err;

	unsigned int pkt_len;



	in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&

		  !before(end_seq, TCP_SKB_CB(skb)->end_seq);



	if (tcp_skb_pcount(skb) > 1 && !in_sack &&

	    after(TCP_SKB_CB(skb)->end_seq, start_seq)) {



		in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq);



		if (!in_sack)

			pkt_len = start_seq - TCP_SKB_CB(skb)->seq;

		else

			pkt_len = end_seq - TCP_SKB_CB(skb)->seq;

		err = tcp_fragment(sk, skb, pkt_len, skb_shinfo(skb)->gso_size);

		if (err < 0)

			return err;

	}



	return in_sack;

}



static int

tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_una)

{
@@ -1333,25 +1365,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_ 
			if (!before(TCP_SKB_CB(skb)->seq, end_seq))

				break;



			in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) &&

				!before(end_seq, TCP_SKB_CB(skb)->end_seq);



			if (tcp_skb_pcount(skb) > 1 && !in_sack &&

			    after(TCP_SKB_CB(skb)->end_seq, start_seq)) {

				unsigned int pkt_len;



				in_sack = !after(start_seq,

						 TCP_SKB_CB(skb)->seq);



				if (!in_sack)

					pkt_len = (start_seq -

						   TCP_SKB_CB(skb)->seq);

				else

					pkt_len = (end_seq -

						   TCP_SKB_CB(skb)->seq);

				if (tcp_fragment(sk, skb, pkt_len, skb_shinfo(skb)->gso_size))

			in_sack = tcp_match_skb_to_sack(sk, skb, start_seq, end_seq);

			if (in_sack < 0)

				break;

			}



			fack_count += tcp_skb_pcount(skb);