From c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Wed, 14 Mar 2007 16:45:19 -0700
Subject: [PATCH] [NETFILTER]: ctnetlink: add support for internal tcp
connection tracking flags handling
This patch let userspace programs set the IP_CT_TCP_BE_LIBERAL flag to
force the pickup of established connections.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/netfilter/nf_conntrack_tcp.h | 5 +++
include/linux/netfilter/nfnetlink_conntrack.h | 4 ++
net/netfilter/nf_conntrack_proto_tcp.c | 45 ++++++++++++++++++-
3 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/include/linux/netfilter/nf_conntrack_tcp.h b/include/linux/netfilter/nf_conntrack_tcp.h
index 007af4c2770b..22ce29995f13 100644
--- a/include/linux/netfilter/nf_conntrack_tcp.h
+++ b/include/linux/netfilter/nf_conntrack_tcp.h
@@ -30,6 +30,11 @@ enum tcp_conntrack {
/* Be liberal in window checking */
#define IP_CT_TCP_FLAG_BE_LIBERAL 0x08
+struct nf_ct_tcp_flags {
+ u_int8_t flags;
+ u_int8_t mask;
+};
+
#ifdef __KERNEL__
struct ip_ct_tcp_state {
diff --git a/include/linux/netfilter/nfnetlink_conntrack.h b/include/linux/netfilter/nfnetlink_conntrack.h
index b5883ccee295..d7c35039721e 100644
--- a/include/linux/netfilter/nfnetlink_conntrack.h
+++ b/include/linux/netfilter/nfnetlink_conntrack.h
@@ -83,6 +83,10 @@ enum ctattr_protoinfo {
enum ctattr_protoinfo_tcp {
CTA_PROTOINFO_TCP_UNSPEC,
CTA_PROTOINFO_TCP_STATE,
+ CTA_PROTOINFO_TCP_WSCALE_ORIGINAL,
+ CTA_PROTOINFO_TCP_WSCALE_REPLY,
+ CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
+ CTA_PROTOINFO_TCP_FLAGS_REPLY,
__CTA_PROTOINFO_TCP_MAX
};
#define CTA_PROTOINFO_TCP_MAX (__CTA_PROTOINFO_TCP_MAX - 1)
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index a1363626bccc..8439768f9d1c 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -1101,11 +1101,26 @@ static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
const struct nf_conn *ct)
{
struct nfattr *nest_parms;
+ struct nf_ct_tcp_flags tmp = {};
read_lock_bh(&tcp_lock);
nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
&ct->proto.tcp.state);
+
+ NFA_PUT(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, sizeof(u_int8_t),
+ &ct->proto.tcp.seen[0].td_scale);
+
+ NFA_PUT(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, sizeof(u_int8_t),
+ &ct->proto.tcp.seen[1].td_scale);
+
+ tmp.flags = ct->proto.tcp.seen[0].flags;
+ NFA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL,
+ sizeof(struct nf_ct_tcp_flags), &tmp);
+
+ tmp.flags = ct->proto.tcp.seen[1].flags;
+ NFA_PUT(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY,
+ sizeof(struct nf_ct_tcp_flags), &tmp);
read_unlock_bh(&tcp_lock);
NFA_NEST_END(skb, nest_parms);
@@ -1118,7 +1133,11 @@ static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
}
static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
- [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
+ [CTA_PROTOINFO_TCP_STATE-1] = sizeof(u_int8_t),
+ [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1] = sizeof(u_int8_t),
+ [CTA_PROTOINFO_TCP_WSCALE_REPLY-1] = sizeof(u_int8_t),
+ [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1] = sizeof(struct nf_ct_tcp_flags),
+ [CTA_PROTOINFO_TCP_FLAGS_REPLY-1] = sizeof(struct nf_ct_tcp_flags)
};
static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
@@ -1142,6 +1161,30 @@ static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
write_lock_bh(&tcp_lock);
ct->proto.tcp.state =
*(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
+
+ if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1]) {
+ struct nf_ct_tcp_flags *attr =
+ NFA_DATA(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL-1]);
+ ct->proto.tcp.seen[0].flags &= ~attr->mask;
+ ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask;
+ }
+
+ if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY-1]) {
+ struct nf_ct_tcp_flags *attr =
+ NFA_DATA(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY-1]);
+ ct->proto.tcp.seen[1].flags &= ~attr->mask;
+ ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask;
+ }
+
+ if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1] &&
+ tb[CTA_PROTOINFO_TCP_WSCALE_REPLY-1] &&
+ ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
+ ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {
+ ct->proto.tcp.seen[0].td_scale = *(u_int8_t *)
+ NFA_DATA(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL-1]);
+ ct->proto.tcp.seen[1].td_scale = *(u_int8_t *)
+ NFA_DATA(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY-1]);
+ }
write_unlock_bh(&tcp_lock);
return 0;
--
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