[NETFILTER]: tcp conntrack: do liberal tracking for picked up connections

Do liberal tracking (only RSTs need to be in-window) for connections picked
up without seeing a SYN to deal with window scaling. Also change logging
of invalid packets not to log packets accepted by liberal tracking to avoid
spamming the logs.

Based on suggestion from James Ralston <ralston@pobox.com>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/netfilter/nf_conntrack_tcp.h b/include/linux/netfilter/nf_conntrack_tcp.h
index 2f4e98b90cc0..007af4c2770b 100644
--- a/include/linux/netfilter/nf_conntrack_tcp.h
+++ b/include/linux/netfilter/nf_conntrack_tcp.h
@@ -27,6 +27,9 @@ enum tcp_conntrack {
 /* This sender sent FIN first */
 #define IP_CT_TCP_FLAG_CLOSE_INIT               0x04
 
+/* Be liberal in window checking */
+#define IP_CT_TCP_FLAG_BE_LIBERAL               0x08
+
 #ifdef __KERNEL__
 
 struct ip_ct_tcp_state {
@@ -34,7 +37,6 @@ struct ip_ct_tcp_state {
         u_int32_t       td_maxend;      /* max of ack + max(win, 1) */
         u_int32_t       td_maxwin;      /* max(win) */
         u_int8_t        td_scale;       /* window scale factor */
-        u_int8_t        loose;          /* used when connection picked up from the middle */
         u_int8_t        flags;          /* per direction options */
 };