Commit 9ec06ff5 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: fix retrans_out leaks 



There's conflicting assumptions in shifting, the caller assumes
that dupsack results in S'ed skbs (or a part of it) for sure but
never gave a hint to tcp_sacktag_one when dsack is actually in
use. Thus DSACK retrans_out -= pcount was not taken and the
counter became out of sync. Remove obstacle from that information
flow to get DSACKs accounted in tcp_sacktag_one as expected.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Tested-by: default avatarDenys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 709ab326

net/ipv4/tcp_input.c

+5 −4
Original line number Diff line number Diff line
@@ -1374,7 +1374,8 @@ static u8 tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, 


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

			   struct tcp_sacktag_state *state,

			   unsigned int pcount, int shifted, int mss)

			   unsigned int pcount, int shifted, int mss,

			   int dup_sack)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
@@ -1410,7 +1411,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, 
	}



	/* We discard results */

	tcp_sacktag_one(skb, sk, state, 0, pcount);

	tcp_sacktag_one(skb, sk, state, 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);
@@ -1561,7 +1562,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, 


	if (!skb_shift(prev, skb, len))

		goto fallback;

	if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss))

	if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))

		goto out;



	/* Hole filled allows collapsing with the next as well, this is very
@@ -1580,7 +1581,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, 
	len = skb->len;

	if (skb_shift(prev, skb, len)) {

		pcount += tcp_skb_pcount(skb);

		tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss);

		tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);

	}



out:

CRA Git | Maintained and supported by SUSTech CRA and CCSE