Commit daef52ba authored by Neal Cardwell's avatar Neal Cardwell Committed by David S. Miller
Browse files

tcp: fix range tcp_shifted_skb() passes to tcp_sacktag_one() 



Fix the newly-SACKed range to be the range of newly-shifted bytes.

Previously - since 832d11c5 -
tcp_shifted_skb() incorrectly called tcp_sacktag_one() with the start
and end sequence numbers of the skb it passes in set to the range just
beyond the range that is newly-SACKed.

This commit also removes a special-case adjustment to lost_cnt_hint in
tcp_shifted_skb() since the pre-existing adjustment of lost_cnt_hint
in tcp_sacktag_one() now properly handles this things now that the
correct start sequence number is passed in.

Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cc9a672e

net/ipv4/tcp_input.c

+10 −9
Original line number Diff line number Diff line
@@ -1388,6 +1388,9 @@ static u8 tcp_sacktag_one(struct sock *sk, 
	return sacked;

}



/* Shift newly-SACKed bytes from this skb to the immediately previous

 * already-SACKed sk_buff. Mark the newly-SACKed bytes as such.

 */

static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,

			   struct tcp_sacktag_state *state,

			   unsigned int pcount, int shifted, int mss,
@@ -1395,12 +1398,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, 
{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *prev = tcp_write_queue_prev(sk, skb);

	u32 start_seq = TCP_SKB_CB(skb)->seq;	/* start of newly-SACKed */

	u32 end_seq = start_seq + shifted;	/* end of newly-SACKed */



	BUG_ON(!pcount);



	if (skb == tp->lost_skb_hint)

		tp->lost_cnt_hint += pcount;



	TCP_SKB_CB(prev)->end_seq += shifted;

	TCP_SKB_CB(skb)->seq += shifted;
@@ -1424,12 +1426,11 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, 
		skb_shinfo(skb)->gso_type = 0;

	}



	/* We discard results */

	tcp_sacktag_one(sk, state,

			TCP_SKB_CB(skb)->sacked,

			TCP_SKB_CB(skb)->seq,

			TCP_SKB_CB(skb)->end_seq,

			dup_sack, pcount);

	/* Adjust counters and hints for the newly sacked sequence range but

	 * discard the return value since prev is already marked.

	 */

	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,

			start_seq, end_seq, dup_sack, pcount);



	/* Difference in this won't matter, both ACKed by the same cumul. ACK */

	TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);

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