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br_netfilter.c
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br_netfilter.c
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/*
* Handle firewalling
* Linux ethernet bridge
*
* Authors:
* Lennert Buytenhek <[email protected]>
* Bart De Schuymer (maintainer) <[email protected]>
*
* Changes:
* Apr 29 2003: physdev module support (bdschuym)
* Jun 19 2003: let arptables see bridged ARP traffic (bdschuym)
* Oct 06 2003: filter encapsulated IP/ARP VLAN traffic on untagged bridge
* (bdschuym)
* Sep 01 2004: add IPv6 filtering (bdschuym)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Lennert dedicates this file to Kerstin Wurdinger.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ip.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter_arp.h>
#include <linux/in_route.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/route.h>
#include <asm/uaccess.h>
#include "br_private.h"
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#define skb_origaddr(skb) (((struct bridge_skb_cb *) \
(skb->nf_bridge->data))->daddr.ipv4)
#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
#ifdef CONFIG_SYSCTL
static struct ctl_table_header *brnf_sysctl_header;
static int brnf_call_iptables __read_mostly = 1;
static int brnf_call_ip6tables __read_mostly = 1;
static int brnf_call_arptables __read_mostly = 1;
static int brnf_filter_vlan_tagged __read_mostly = 1;
#else
#define brnf_filter_vlan_tagged 1
#endif
int brnf_deferred_hooks;
EXPORT_SYMBOL_GPL(brnf_deferred_hooks);
static __be16 inline vlan_proto(const struct sk_buff *skb)
{
return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
}
#define IS_VLAN_IP(skb) \
(skb->protocol == htons(ETH_P_8021Q) && \
vlan_proto(skb) == htons(ETH_P_IP) && \
brnf_filter_vlan_tagged)
#define IS_VLAN_IPV6(skb) \
(skb->protocol == htons(ETH_P_8021Q) && \
vlan_proto(skb) == htons(ETH_P_IPV6) &&\
brnf_filter_vlan_tagged)
#define IS_VLAN_ARP(skb) \
(skb->protocol == htons(ETH_P_8021Q) && \
vlan_proto(skb) == htons(ETH_P_ARP) && \
brnf_filter_vlan_tagged)
/* We need these fake structures to make netfilter happy --
* lots of places assume that skb->dst != NULL, which isn't
* all that unreasonable.
*
* Currently, we fill in the PMTU entry because netfilter
* refragmentation needs it, and the rt_flags entry because
* ipt_REJECT needs it. Future netfilter modules might
* require us to fill additional fields. */
static struct net_device __fake_net_device = {
.hard_header_len = ETH_HLEN
};
static struct rtable __fake_rtable = {
.u = {
.dst = {
.__refcnt = ATOMIC_INIT(1),
.dev = &__fake_net_device,
.path = &__fake_rtable.u.dst,
.metrics = {[RTAX_MTU - 1] = 1500},
.flags = DST_NOXFRM,
}
},
.rt_flags = 0,
};
static inline struct net_device *bridge_parent(const struct net_device *dev)
{
struct net_bridge_port *port = rcu_dereference(dev->br_port);
return port ? port->br->dev : NULL;
}
static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
{
skb->nf_bridge = kzalloc(sizeof(struct nf_bridge_info), GFP_ATOMIC);
if (likely(skb->nf_bridge))
atomic_set(&(skb->nf_bridge->use), 1);
return skb->nf_bridge;
}
static inline void nf_bridge_save_header(struct sk_buff *skb)
{
int header_size = ETH_HLEN;
if (skb->protocol == htons(ETH_P_8021Q))
header_size += VLAN_HLEN;
memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
}
/*
* When forwarding bridge frames, we save a copy of the original
* header before processing.
*/
int nf_bridge_copy_header(struct sk_buff *skb)
{
int err;
int header_size = ETH_HLEN;
if (skb->protocol == htons(ETH_P_8021Q))
header_size += VLAN_HLEN;
err = skb_cow(skb, header_size);
if (err)
return err;
memcpy(skb->data - header_size, skb->nf_bridge->data, header_size);
if (skb->protocol == htons(ETH_P_8021Q))
__skb_push(skb, VLAN_HLEN);
return 0;
}
/* PF_BRIDGE/PRE_ROUTING *********************************************/
/* Undo the changes made for ip6tables PREROUTING and continue the
* bridge PRE_ROUTING hook. */
static int br_nf_pre_routing_finish_ipv6(struct sk_buff *skb)
{
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
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;
skb->dst = (struct dst_entry *)&__fake_rtable;
dst_hold(skb->dst);
skb->dev = nf_bridge->physindev;
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
br_handle_frame_finish, 1);
return 0;
}
static void __br_dnat_complain(void)
{
static unsigned long last_complaint;
if (jiffies - last_complaint >= 5 * HZ) {
printk(KERN_WARNING "Performing cross-bridge DNAT requires IP "
"forwarding to be enabled\n");
last_complaint = jiffies;
}
}
/* This requires some explaining. If DNAT has taken place,
* we will need to fix up the destination Ethernet address,
* and this is a tricky process.
*
* There are two cases to consider:
* 1. The packet was DNAT'ed to a device in the same bridge
* port group as it was received on. We can still bridge
* the packet.
* 2. The packet was DNAT'ed to a different device, either
* a non-bridged device or another bridge port group.
* The packet will need to be routed.
*
* The correct way of distinguishing between these two cases is to
* call ip_route_input() and to look at skb->dst->dev, which is
* changed to the destination device if ip_route_input() succeeds.
*
* Let us first consider the case that ip_route_input() succeeds:
*
* If skb->dst->dev equals the logical bridge device the packet
* came in on, we can consider this bridging. We then call
* skb->dst->output() which will make the packet enter br_nf_local_out()
* not much later. In that function it is assured that the iptables
* FORWARD chain is traversed for the packet.
*
* 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.
*
* Let us now consider the case that ip_route_input() fails:
*
* 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
* thinks we're handling a locally generated packet and won't care
* if IP forwarding is allowed. We send a warning message to the users's
* log telling her to put IP forwarding on.
*
* ip_route_input() will also fail if there is no route available.
* In that case we just drop the packet.
*
* --Lennert, 20020411
* --Bart, 20020416 (updated)
* --Bart, 20021007 (updated) */
static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb)
{
if (skb->pkt_type == PACKET_OTHERHOST) {
skb->pkt_type = PACKET_HOST;
skb->nf_bridge->mask |= BRNF_PKT_TYPE;
}
skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
skb->dev = bridge_parent(skb->dev);
if (!skb->dev)
kfree_skb(skb);
else {
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull(skb, VLAN_HLEN);
skb->nh.raw += VLAN_HLEN;
}
skb->dst->output(skb);
}
return 0;
}
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;
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)) {
struct rtable *rt;
struct flowi fl = {
.nl_u = {
.ip4_u = {
.daddr = iph->daddr,
.saddr = 0,
.tos = RT_TOS(iph->tos) },
},
.proto = 0,
};
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) {
skb->dst = (struct dst_entry *)rt;
goto bridged_dnat;
}
__br_dnat_complain();
dst_release((struct dst_entry *)rt);
}
kfree_skb(skb);
return 0;
} else {
if (skb->dst->dev == dev) {
bridged_dnat:
/* Tell br_nf_local_out this is a
* bridged frame */
nf_bridge->mask |= BRNF_BRIDGED_DNAT;
skb->dev = nf_bridge->physindev;
if (skb->protocol ==
htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING,
skb, skb->dev, NULL,
br_nf_pre_routing_finish_bridge,
1);
return 0;
}
memcpy(eth_hdr(skb)->h_dest, dev->dev_addr, ETH_ALEN);
skb->pkt_type = PACKET_HOST;
}
} else {
skb->dst = (struct dst_entry *)&__fake_rtable;
dst_hold(skb->dst);
}
skb->dev = nf_bridge->physindev;
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
br_handle_frame_finish, 1);
return 0;
}
/* Some common code for IPv4/IPv6 */
static struct net_device *setup_pre_routing(struct sk_buff *skb)
{
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
if (skb->pkt_type == PACKET_OTHERHOST) {
skb->pkt_type = PACKET_HOST;
nf_bridge->mask |= BRNF_PKT_TYPE;
}
nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
nf_bridge->physindev = skb->dev;
skb->dev = bridge_parent(skb->dev);
return skb->dev;
}
/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
static int check_hbh_len(struct sk_buff *skb)
{
unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
u32 pkt_len;
int off = raw - skb->nh.raw;
int len = (raw[1] + 1) << 3;
if ((raw + len) - skb->data > skb_headlen(skb))
goto bad;
off += 2;
len -= 2;
while (len > 0) {
int optlen = skb->nh.raw[off + 1] + 2;
switch (skb->nh.raw[off]) {
case IPV6_TLV_PAD0:
optlen = 1;
break;
case IPV6_TLV_PADN:
break;
case IPV6_TLV_JUMBO:
if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
goto bad;
pkt_len = ntohl(*(__be32 *) (skb->nh.raw + off + 2));
if (pkt_len <= IPV6_MAXPLEN ||
skb->nh.ipv6h->payload_len)
goto bad;
if (pkt_len > skb->len - sizeof(struct ipv6hdr))
goto bad;
if (pskb_trim_rcsum(skb,
pkt_len + sizeof(struct ipv6hdr)))
goto bad;
break;
default:
if (optlen > len)
goto bad;
break;
}
off += optlen;
len -= optlen;
}
if (len == 0)
return 0;
bad:
return -1;
}
/* Replicate the checks that IPv6 does on packet reception and pass the packet
* to ip6tables, which doesn't support NAT, so things are fairly simple. */
static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct ipv6hdr *hdr;
u32 pkt_len;
if (skb->len < sizeof(struct ipv6hdr))
goto inhdr_error;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto inhdr_error;
hdr = skb->nh.ipv6h;
if (hdr->version != 6)
goto inhdr_error;
pkt_len = ntohs(hdr->payload_len);
if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
goto inhdr_error;
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
goto inhdr_error;
}
if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
goto inhdr_error;
nf_bridge_put(skb->nf_bridge);
if (!nf_bridge_alloc(skb))
return NF_DROP;
if (!setup_pre_routing(skb))
return NF_DROP;
NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
br_nf_pre_routing_finish_ipv6);
return NF_STOLEN;
inhdr_error:
return NF_DROP;
}
/* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
* Replicate the checks that IPv4 does on packet reception.
* Set skb->dev to the bridge device (i.e. parent of the
* receiving device) to make netfilter happy, the REDIRECT
* target in particular. Save the original destination IP
* address to be able to detect DNAT afterwards. */
static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct iphdr *iph;
__u32 len;
struct sk_buff *skb = *pskb;
if (skb->protocol == htons(ETH_P_IPV6) || IS_VLAN_IPV6(skb)) {
#ifdef CONFIG_SYSCTL
if (!brnf_call_ip6tables)
return NF_ACCEPT;
#endif
if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
goto out;
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull_rcsum(skb, VLAN_HLEN);
skb->nh.raw += VLAN_HLEN;
}
return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
}
#ifdef CONFIG_SYSCTL
if (!brnf_call_iptables)
return NF_ACCEPT;
#endif
if (skb->protocol != htons(ETH_P_IP) && !IS_VLAN_IP(skb))
return NF_ACCEPT;
if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
goto out;
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull_rcsum(skb, VLAN_HLEN);
skb->nh.raw += VLAN_HLEN;
}
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto inhdr_error;
iph = skb->nh.iph;
if (iph->ihl < 5 || iph->version != 4)
goto inhdr_error;
if (!pskb_may_pull(skb, 4 * iph->ihl))
goto inhdr_error;
iph = skb->nh.iph;
if (ip_fast_csum((__u8 *) iph, iph->ihl) != 0)
goto inhdr_error;
len = ntohs(iph->tot_len);
if (skb->len < len || len < 4 * iph->ihl)
goto inhdr_error;
pskb_trim_rcsum(skb, len);
nf_bridge_put(skb->nf_bridge);
if (!nf_bridge_alloc(skb))
return NF_DROP;
if (!setup_pre_routing(skb))
return NF_DROP;
store_orig_dstaddr(skb);
NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
br_nf_pre_routing_finish);
return NF_STOLEN;
inhdr_error:
// IP_INC_STATS_BH(IpInHdrErrors);
out:
return NF_DROP;
}
/* PF_BRIDGE/LOCAL_IN ************************************************/
/* The packet is locally destined, which requires a real
* dst_entry, so detach the fake one. On the way up, the
* packet would pass through PRE_ROUTING again (which already
* took place when the packet entered the bridge), but we
* register an IPv4 PRE_ROUTING 'sabotage' hook that will
* prevent this from happening. */
static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *skb = *pskb;
if (skb->dst == (struct dst_entry *)&__fake_rtable) {
dst_release(skb->dst);
skb->dst = NULL;
}
return NF_ACCEPT;
}
/* PF_BRIDGE/FORWARD *************************************************/
static int br_nf_forward_finish(struct sk_buff *skb)
{
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
struct net_device *in;
if (skb->protocol != htons(ETH_P_ARP) && !IS_VLAN_ARP(skb)) {
in = nf_bridge->physindev;
if (nf_bridge->mask & BRNF_PKT_TYPE) {
skb->pkt_type = PACKET_OTHERHOST;
nf_bridge->mask ^= BRNF_PKT_TYPE;
}
} else {
in = *((struct net_device **)(skb->cb));
}
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_FORWARD, skb, in,
skb->dev, br_forward_finish, 1);
return 0;
}
/* This is the 'purely bridged' case. For IP, we pass the packet to
* netfilter with indev and outdev set to the bridge device,
* but we are still able to filter on the 'real' indev/outdev
* because of the physdev module. For ARP, indev and outdev are the
* bridge ports. */
static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *skb = *pskb;
struct nf_bridge_info *nf_bridge;
struct net_device *parent;
int pf;
if (!skb->nf_bridge)
return NF_ACCEPT;
parent = bridge_parent(out);
if (!parent)
return NF_DROP;
if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
pf = PF_INET;
else
pf = PF_INET6;
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull(*pskb, VLAN_HLEN);
(*pskb)->nh.raw += VLAN_HLEN;
}
nf_bridge = skb->nf_bridge;
if (skb->pkt_type == PACKET_OTHERHOST) {
skb->pkt_type = PACKET_HOST;
nf_bridge->mask |= BRNF_PKT_TYPE;
}
/* The physdev module checks on this */
nf_bridge->mask |= BRNF_BRIDGED;
nf_bridge->physoutdev = skb->dev;
NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
br_nf_forward_finish);
return NF_STOLEN;
}
static unsigned int br_nf_forward_arp(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *skb = *pskb;
struct net_device **d = (struct net_device **)(skb->cb);
#ifdef CONFIG_SYSCTL
if (!brnf_call_arptables)
return NF_ACCEPT;
#endif
if (skb->protocol != htons(ETH_P_ARP)) {
if (!IS_VLAN_ARP(skb))
return NF_ACCEPT;
skb_pull(*pskb, VLAN_HLEN);
(*pskb)->nh.raw += VLAN_HLEN;
}
if (skb->nh.arph->ar_pln != 4) {
if (IS_VLAN_ARP(skb)) {
skb_push(*pskb, VLAN_HLEN);
(*pskb)->nh.raw -= VLAN_HLEN;
}
return NF_ACCEPT;
}
*d = (struct net_device *)in;
NF_HOOK(NF_ARP, NF_ARP_FORWARD, skb, (struct net_device *)in,
(struct net_device *)out, br_nf_forward_finish);
return NF_STOLEN;
}
/* PF_BRIDGE/LOCAL_OUT ***********************************************/
static int br_nf_local_out_finish(struct sk_buff *skb)
{
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK_THRESH(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
br_forward_finish, NF_BR_PRI_FIRST + 1);
return 0;
}
/* This function sees both locally originated IP packets and forwarded
* IP packets (in both cases the destination device is a bridge
* device). It also sees bridged-and-DNAT'ed packets.
* To be able to filter on the physical bridge devices (with the physdev
* module), we steal packets destined to a bridge device away from the
* PF_INET/FORWARD and PF_INET/OUTPUT hook functions, and give them back later,
* when we have determined the real output device. This is done in here.
*
* If (nf_bridge->mask & BRNF_BRIDGED_DNAT) then the packet is bridged
* and we fake the PF_BRIDGE/FORWARD hook. The function br_nf_forward()
* will then fake the PF_INET/FORWARD hook. br_nf_local_out() has priority
* NF_BR_PRI_FIRST, so no relevant PF_BRIDGE/INPUT functions have been nor
* will be executed.
* Otherwise, if nf_bridge->physindev is NULL, the bridge-nf code never touched
* this packet before, and so the packet was locally originated. We fake
* the PF_INET/LOCAL_OUT hook.
* Finally, if nf_bridge->physindev isn't NULL, then the packet was IP routed,
* so we fake the PF_INET/FORWARD hook. ip_sabotage_out() makes sure
* even routed packets that didn't arrive on a bridge interface have their
* nf_bridge->physindev set. */
static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct net_device *realindev, *realoutdev;
struct sk_buff *skb = *pskb;
struct nf_bridge_info *nf_bridge;
int pf;
if (!skb->nf_bridge)
return NF_ACCEPT;
if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
pf = PF_INET;
else
pf = PF_INET6;
nf_bridge = skb->nf_bridge;
nf_bridge->physoutdev = skb->dev;
realindev = nf_bridge->physindev;
/* Bridged, take PF_BRIDGE/FORWARD.
* (see big note in front of br_nf_pre_routing_finish) */
if (nf_bridge->mask & BRNF_BRIDGED_DNAT) {
if (nf_bridge->mask & BRNF_PKT_TYPE) {
skb->pkt_type = PACKET_OTHERHOST;
nf_bridge->mask ^= BRNF_PKT_TYPE;
}
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_push(skb, VLAN_HLEN);
skb->nh.raw -= VLAN_HLEN;
}
NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, realindev,
skb->dev, br_forward_finish);
goto out;
}
realoutdev = bridge_parent(skb->dev);
if (!realoutdev)
return NF_DROP;
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
/* iptables should match -o br0.x */
if (nf_bridge->netoutdev)
realoutdev = nf_bridge->netoutdev;
#endif
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull(skb, VLAN_HLEN);
(*pskb)->nh.raw += VLAN_HLEN;
}
/* IP forwarded traffic has a physindev, locally
* generated traffic hasn't. */
if (realindev != NULL) {
if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT)) {
struct net_device *parent = bridge_parent(realindev);
if (parent)
realindev = parent;
}
NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
realoutdev, br_nf_local_out_finish,
NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
} else {
NF_HOOK_THRESH(pf, NF_IP_LOCAL_OUT, skb, realindev,
realoutdev, br_nf_local_out_finish,
NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT + 1);
}
out:
return NF_STOLEN;
}
static int br_nf_dev_queue_xmit(struct sk_buff *skb)
{
if (skb->protocol == htons(ETH_P_IP) &&
skb->len > skb->dev->mtu &&
!skb_is_gso(skb))
return ip_fragment(skb, br_dev_queue_push_xmit);
else
return br_dev_queue_push_xmit(skb);
}
/* PF_BRIDGE/POST_ROUTING ********************************************/
static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *skb = *pskb;
struct nf_bridge_info *nf_bridge = (*pskb)->nf_bridge;
struct net_device *realoutdev = bridge_parent(skb->dev);
int pf;
#ifdef CONFIG_NETFILTER_DEBUG
/* Be very paranoid. This probably won't happen anymore, but let's
* keep the check just to be sure... */
if (skb->mac.raw < skb->head || skb->mac.raw + ETH_HLEN > skb->data) {
printk(KERN_CRIT "br_netfilter: Argh!! br_nf_post_routing: "
"bad mac.raw pointer.\n");
goto print_error;
}
#endif
if (!nf_bridge)
return NF_ACCEPT;
if (!realoutdev)
return NF_DROP;
if (skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb))
pf = PF_INET;
else
pf = PF_INET6;
#ifdef CONFIG_NETFILTER_DEBUG
if (skb->dst == NULL) {
printk(KERN_INFO "br_netfilter post_routing: skb->dst == NULL\n");
goto print_error;
}
#endif
/* We assume any code from br_dev_queue_push_xmit onwards doesn't care
* about the value of skb->pkt_type. */
if (skb->pkt_type == PACKET_OTHERHOST) {
skb->pkt_type = PACKET_HOST;
nf_bridge->mask |= BRNF_PKT_TYPE;
}
if (skb->protocol == htons(ETH_P_8021Q)) {
skb_pull(skb, VLAN_HLEN);
skb->nh.raw += VLAN_HLEN;
}
nf_bridge_save_header(skb);
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
if (nf_bridge->netoutdev)
realoutdev = nf_bridge->netoutdev;
#endif
NF_HOOK(pf, NF_IP_POST_ROUTING, skb, NULL, realoutdev,
br_nf_dev_queue_xmit);
return NF_STOLEN;
#ifdef CONFIG_NETFILTER_DEBUG
print_error:
if (skb->dev != NULL) {
printk("[%s]", skb->dev->name);
if (realoutdev)
printk("[%s]", realoutdev->name);
}
printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
skb->data);
dump_stack();
return NF_ACCEPT;
#endif
}
/* IP/SABOTAGE *****************************************************/
/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
* for the second time. */
static unsigned int ip_sabotage_in(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
if ((*pskb)->nf_bridge &&
!((*pskb)->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)) {
return NF_STOP;
}
return NF_ACCEPT;
}
/* Postpone execution of PF_INET(6)/FORWARD, PF_INET(6)/LOCAL_OUT
* and PF_INET(6)/POST_ROUTING until we have done the forwarding
* decision in the bridge code and have determined nf_bridge->physoutdev. */
static unsigned int ip_sabotage_out(unsigned int hook, struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *skb = *pskb;
if ((out->hard_start_xmit == br_dev_xmit &&
okfn != br_nf_forward_finish &&
okfn != br_nf_local_out_finish && okfn != br_nf_dev_queue_xmit)
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
|| ((out->priv_flags & IFF_802_1Q_VLAN) &&
VLAN_DEV_INFO(out)->real_dev->hard_start_xmit == br_dev_xmit)
#endif
) {
struct nf_bridge_info *nf_bridge;
if (!skb->nf_bridge) {
#ifdef CONFIG_SYSCTL
/* This code is executed while in the IP(v6) stack,
the version should be 4 or 6. We can't use
skb->protocol because that isn't set on
PF_INET(6)/LOCAL_OUT. */
struct iphdr *ip = skb->nh.iph;
if (ip->version == 4 && !brnf_call_iptables)
return NF_ACCEPT;
else if (ip->version == 6 && !brnf_call_ip6tables)
return NF_ACCEPT;
else if (!brnf_deferred_hooks)
return NF_ACCEPT;
#endif
if (hook == NF_IP_POST_ROUTING)
return NF_ACCEPT;
if (!nf_bridge_alloc(skb))
return NF_DROP;
}
nf_bridge = skb->nf_bridge;
/* This frame will arrive on PF_BRIDGE/LOCAL_OUT and we
* will need the indev then. For a brouter, the real indev
* can be a bridge port, so we make sure br_nf_local_out()
* doesn't use the bridge parent of the indev by using
* the BRNF_DONT_TAKE_PARENT mask. */
if (hook == NF_IP_FORWARD && nf_bridge->physindev == NULL) {
nf_bridge->mask |= BRNF_DONT_TAKE_PARENT;
nf_bridge->physindev = (struct net_device *)in;
}
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
/* the iptables outdev is br0.x, not br0 */
if (out->priv_flags & IFF_802_1Q_VLAN)
nf_bridge->netoutdev = (struct net_device *)out;
#endif
return NF_STOP;
}
return NF_ACCEPT;
}
/* For br_nf_local_out we need (prio = NF_BR_PRI_FIRST), to insure that innocent
* PF_BRIDGE/NF_BR_LOCAL_OUT functions don't get bridged traffic as input.
* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
* ip_refrag() can return NF_STOLEN. */
static struct nf_hook_ops br_nf_ops[] = {
{ .hook = br_nf_pre_routing,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_PRE_ROUTING,
.priority = NF_BR_PRI_BRNF, },
{ .hook = br_nf_local_in,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_LOCAL_IN,
.priority = NF_BR_PRI_BRNF, },
{ .hook = br_nf_forward_ip,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_FORWARD,
.priority = NF_BR_PRI_BRNF - 1, },
{ .hook = br_nf_forward_arp,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_FORWARD,
.priority = NF_BR_PRI_BRNF, },
{ .hook = br_nf_local_out,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_LOCAL_OUT,
.priority = NF_BR_PRI_FIRST, },
{ .hook = br_nf_post_routing,
.owner = THIS_MODULE,
.pf = PF_BRIDGE,
.hooknum = NF_BR_POST_ROUTING,
.priority = NF_BR_PRI_LAST, },
{ .hook = ip_sabotage_in,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_PRE_ROUTING,
.priority = NF_IP_PRI_FIRST, },
{ .hook = ip_sabotage_in,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_PRE_ROUTING,
.priority = NF_IP6_PRI_FIRST, },
{ .hook = ip_sabotage_out,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_FORWARD,
.priority = NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD, },
{ .hook = ip_sabotage_out,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_IP6_FORWARD,
.priority = NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD, },
{ .hook = ip_sabotage_out,
.owner = THIS_MODULE,
.pf = PF_INET,
.hooknum = NF_IP_LOCAL_OUT,
.priority = NF_IP_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
{ .hook = ip_sabotage_out,