diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/bridge/br_netfilter.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index ac47ba2ba02..bd221ad52ea 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -34,6 +34,7 @@ #include <linux/netfilter_ipv6.h> #include <linux/netfilter_arp.h> #include <linux/in_route.h> +#include <linux/inetdevice.h> #include <net/ip.h> #include <net/ipv6.h> @@ -221,10 +222,14 @@ static void __br_dnat_complain(void) * * Otherwise, the packet is considered to be routed and we just * change the destination MAC address so that the packet will - * later be passed up to the IP stack to be routed. + * later be passed up to the IP stack to be routed. For a redirected + * packet, ip_route_input() will give back the localhost as output device, + * which differs from the bridge device. * * Let us now consider the case that ip_route_input() fails: * + * This can be because the destination address is martian, in which case + * the packet will be dropped. * After a "echo '0' > /proc/sys/net/ipv4/ip_forward" ip_route_input() * will fail, while __ip_route_output_key() will return success. The source * address for __ip_route_output_key() is set to zero, so __ip_route_output_key @@ -237,7 +242,8 @@ static void __br_dnat_complain(void) * * --Lennert, 20020411 * --Bart, 20020416 (updated) - * --Bart, 20021007 (updated) */ + * --Bart, 20021007 (updated) + * --Bart, 20062711 (updated) */ static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb) { if (skb->pkt_type == PACKET_OTHERHOST) { @@ -264,15 +270,15 @@ static int br_nf_pre_routing_finish(struct sk_buff *skb) struct net_device *dev = skb->dev; struct iphdr *iph = skb->nh.iph; struct nf_bridge_info *nf_bridge = skb->nf_bridge; + int err; if (nf_bridge->mask & BRNF_PKT_TYPE) { skb->pkt_type = PACKET_OTHERHOST; nf_bridge->mask ^= BRNF_PKT_TYPE; } nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING; - if (dnat_took_place(skb)) { - if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev)) { + if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) { struct rtable *rt; struct flowi fl = { .nl_u = { @@ -283,19 +289,33 @@ static int br_nf_pre_routing_finish(struct sk_buff *skb) }, .proto = 0, }; + struct in_device *in_dev = in_dev_get(dev); + + /* If err equals -EHOSTUNREACH the error is due to a + * martian destination or due to the fact that + * forwarding is disabled. For most martian packets, + * ip_route_output_key() will fail. It won't fail for 2 types of + * martian destinations: loopback destinations and destination + * 0.0.0.0. In both cases the packet will be dropped because the + * destination is the loopback device and not the bridge. */ + if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev)) + goto free_skb; if (!ip_route_output_key(&rt, &fl)) { /* - Bridged-and-DNAT'ed traffic doesn't - * require ip_forwarding. - * - Deal with redirected traffic. */ - if (((struct dst_entry *)rt)->dev == dev || - rt->rt_type == RTN_LOCAL) { + * require ip_forwarding. */ + if (((struct dst_entry *)rt)->dev == dev) { skb->dst = (struct dst_entry *)rt; goto bridged_dnat; } + /* we are sure that forwarding is disabled, so printing + * this message is no problem. Note that the packet could + * still have a martian destination address, in which case + * the packet could be dropped even if forwarding were enabled */ __br_dnat_complain(); dst_release((struct dst_entry *)rt); } +free_skb: kfree_skb(skb); return 0; } else { |