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[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: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-10-11 17:34:25 -07:00 committed by David S. Miller
parent f6fb128d27
commit d193594299
1 changed files with 35 additions and 19 deletions
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54
net/ipv4/tcp_input.c
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@ -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))
break;
}
in_sack = tcp_match_skb_to_sack(sk, skb, start_seq, end_seq);
if (in_sack < 0)
break;
fack_count += tcp_skb_pcount(skb);