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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-10-12 04:34:25 +0400
committerDavid S. Miller <davem@davemloft.net>2007-10-12 04:34:25 +0400
commitd193594299064d386a2705928cd61ab2ca3d7cee (patch)
treec84b5bde72a9f64e5504a9d05e88c8a5b628854e /net
parentf6fb128d272eb7b0f1a8be78153a724545e28be8 (diff)
downloadlinux-d193594299064d386a2705928cd61ab2ca3d7cee.tar.xz
[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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c54
1 files changed, 35 insertions, 19 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 50047045df62..bd18c252dee4 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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);