From c68cd6cc21eb329c47ff020ff7412bf58176984e Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 17 Jun 2010 06:12:26 +0200 Subject: netfilter: nf_nat: support user-specified SNAT rules in LOCAL_IN 2.6.34 introduced 'conntrack zones' to deal with cases where packets from multiple identical networks are handled by conntrack/NAT. Packets are looped through veth devices, during which they are NATed to private addresses, after which they can continue normally through the stack and possibly have NAT rules applied a second time. This works well, but is needlessly complicated for cases where only a single SNAT/DNAT mapping needs to be applied to these packets. In that case, all that needs to be done is to assign each network to a seperate zone and perform NAT as usual. However this doesn't work for packets destined for the machine performing NAT itself since its corrently not possible to configure SNAT mappings for the LOCAL_IN chain. This patch adds a new INPUT chain to the NAT table and changes the targets performing SNAT to be usable in that chain. Example usage with two identical networks (192.168.0.0/24) on eth0/eth1: iptables -t raw -A PREROUTING -i eth0 -j CT --zone 1 iptables -t raw -A PREROUTING -i eth0 -j MARK --set-mark 1 iptables -t raw -A PREROUTING -i eth1 -j CT --zone 2 iptabels -t raw -A PREROUTING -i eth1 -j MARK --set-mark 2 iptables -t nat -A INPUT -m mark --mark 1 -j NETMAP --to 10.0.0.0/24 iptables -t nat -A POSTROUTING -m mark --mark 1 -j NETMAP --to 10.0.0.0/24 iptables -t nat -A INPUT -m mark --mark 2 -j NETMAP --to 10.0.1.0/24 iptables -t nat -A POSTROUTING -m mark --mark 2 -j NETMAP --to 10.0.1.0/24 iptables -t raw -A PREROUTING -d 10.0.0.0/24 -j CT --zone 1 iptables -t raw -A OUTPUT -d 10.0.0.0/24 -j CT --zone 1 iptables -t raw -A PREROUTING -d 10.0.1.0/24 -j CT --zone 2 iptables -t raw -A OUTPUT -d 10.0.1.0/24 -j CT --zone 2 iptables -t nat -A PREROUTING -d 10.0.0.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A OUTPUT -d 10.0.0.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A PREROUTING -d 10.0.1.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A OUTPUT -d 10.0.1.0/24 -j NETMAP --to 192.168.0.0/24 Signed-off-by: Patrick McHardy --- include/net/netfilter/nf_nat_rule.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_nat_rule.h b/include/net/netfilter/nf_nat_rule.h index e4a18ae..2890bdc 100644 --- a/include/net/netfilter/nf_nat_rule.h +++ b/include/net/netfilter/nf_nat_rule.h @@ -12,6 +12,4 @@ extern int nf_nat_rule_find(struct sk_buff *skb, const struct net_device *out, struct nf_conn *ct); -extern unsigned int -alloc_null_binding(struct nf_conn *ct, unsigned int hooknum); #endif /* _NF_NAT_RULE_H */ -- cgit v1.1