diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_proto_tcp.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 984a8d1..44d1ea3 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -28,6 +28,7 @@ #include <net/netfilter/nf_conntrack_l4proto.h> #include <net/netfilter/nf_conntrack_ecache.h> #include <net/netfilter/nf_conntrack_seqadj.h> +#include <net/netfilter/nf_conntrack_synproxy.h> #include <net/netfilter/nf_log.h> #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> @@ -946,6 +947,21 @@ static int tcp_packet(struct nf_conn *ct, "state %s ", tcp_conntrack_names[old_state]); return NF_ACCEPT; case TCP_CONNTRACK_MAX: + /* Special case for SYN proxy: when the SYN to the server or + * the SYN/ACK from the server is lost, the client may transmit + * a keep-alive packet while in SYN_SENT state. This needs to + * be associated with the original conntrack entry in order to + * generate a new SYN with the correct sequence number. + */ + if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT && + index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL && + ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL && + ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) { + pr_debug("nf_ct_tcp: SYN proxy client keep alive\n"); + spin_unlock_bh(&ct->lock); + return NF_ACCEPT; + } + /* Invalid packet */ pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n", dir, get_conntrack_index(th), old_state); |
