From faecbb45ebefb20260ad4a631e011e93c896cb73 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 20 May 2015 13:42:25 +0200 Subject: [PATCH] Revert "netfilter: bridge: query conntrack about skb dnat" This reverts commit c055d5b03bb4cb69d349d787c9787c0383abd8b2. There are two issues: 'dnat_took_place' made me think that this is related to -j DNAT/MASQUERADE. But thats only one part of the story. This is also relevant for SNAT when we undo snat translation in reverse/reply direction. Furthermore, I originally wanted to do this mainly to avoid storing ipv6 addresses once we make DNAT/REDIRECT work for ipv6 on bridges. However, I forgot about SNPT/DNPT which is stateless. So we can't escape storing address for ipv6 anyway. Might as well do it for ipv4 too. Reported-and-tested-by: Bernhard Thaler Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/skbuff.h | 1 + net/bridge/br_netfilter.c | 27 +++++++++------------------ 2 files changed, 10 insertions(+), 18 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 66e374d62f64..f15154a879c7 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -176,6 +176,7 @@ struct nf_bridge_info { struct net_device *physindev; struct net_device *physoutdev; char neigh_header[8]; + __be32 ipv4_daddr; }; #endif diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index ab55e2472beb..60ddfbeb47f5 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -37,10 +37,6 @@ #include #include -#if IS_ENABLED(CONFIG_NF_CONNTRACK) -#include -#endif - #include #include "br_private.h" #ifdef CONFIG_SYSCTL @@ -350,24 +346,15 @@ static int br_nf_pre_routing_finish_bridge(struct sock *sk, struct sk_buff *skb) return 0; } -static bool dnat_took_place(const struct sk_buff *skb) +static bool daddr_was_changed(const struct sk_buff *skb, + const struct nf_bridge_info *nf_bridge) { -#if IS_ENABLED(CONFIG_NF_CONNTRACK) - enum ip_conntrack_info ctinfo; - struct nf_conn *ct; - - ct = nf_ct_get(skb, &ctinfo); - if (!ct || nf_ct_is_untracked(ct)) - return false; - - return test_bit(IPS_DST_NAT_BIT, &ct->status); -#else - return false; -#endif + return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr; } /* This requires some explaining. If DNAT has taken place, * we will need to fix up the destination Ethernet address. + * This is also true when SNAT takes place (for the reply direction). * * There are two cases to consider: * 1. The packet was DNAT'ed to a device in the same bridge @@ -421,7 +408,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb) nf_bridge->pkt_otherhost = false; } nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; - if (dnat_took_place(skb)) { + if (daddr_was_changed(skb, nf_bridge)) { if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) { struct in_device *in_dev = __in_dev_get_rcu(dev); @@ -632,6 +619,7 @@ static unsigned int br_nf_pre_routing(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct nf_hook_state *state) { + struct nf_bridge_info *nf_bridge; struct net_bridge_port *p; struct net_bridge *br; __u32 len = nf_bridge_encap_header_len(skb); @@ -669,6 +657,9 @@ static unsigned int br_nf_pre_routing(const struct nf_hook_ops *ops, if (!setup_pre_routing(skb)) return NF_DROP; + nf_bridge = nf_bridge_info_get(skb); + nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr; + skb->protocol = htons(ETH_P_IP); NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->sk, skb,