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-rw-r--r--net/bridge/br_netfilter.c1087
1 files changed, 1087 insertions, 0 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
new file mode 100644
index 000000000000..be03d3ad2648
--- /dev/null
+++ b/net/bridge/br_netfilter.c
@@ -0,0 +1,1087 @@
+/*
+ * Handle firewalling
+ * Linux ethernet bridge
+ *
+ * Authors:
+ * Lennert Buytenhek <buytenh@gnu.org>
+ * Bart De Schuymer (maintainer) <bdschuym@pandora.be>
+ *
+ * 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_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 <asm/uaccess.h>
+#include <asm/checksum.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)
+
+#define has_bridge_parent(device) ((device)->br_port != NULL)
+#define bridge_parent(device) ((device)->br_port->br->dev)
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table_header *brnf_sysctl_header;
+static int brnf_call_iptables = 1;
+static int brnf_call_ip6tables = 1;
+static int brnf_call_arptables = 1;
+static int brnf_filter_vlan_tagged = 1;
+#else
+#define brnf_filter_vlan_tagged 1
+#endif
+
+#define IS_VLAN_IP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
+ hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IP) && \
+ brnf_filter_vlan_tagged)
+#define IS_VLAN_IPV6 (skb->protocol == __constant_htons(ETH_P_8021Q) && \
+ hdr->h_vlan_encapsulated_proto == __constant_htons(ETH_P_IPV6) && \
+ brnf_filter_vlan_tagged)
+#define IS_VLAN_ARP (skb->protocol == __constant_htons(ETH_P_8021Q) && \
+ hdr->h_vlan_encapsulated_proto == __constant_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},
+ }
+ },
+ .rt_flags = 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;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_BR_PRE_ROUTING);
+#endif
+
+ 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 == __constant_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)
+{
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug |= (1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_FORWARD);
+#endif
+
+ 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->protocol == __constant_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;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_BR_PRE_ROUTING);
+#endif
+
+ 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. */
+ if (((struct dst_entry *)rt)->dev == dev) {
+ 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 ==
+ __constant_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 == __constant_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 void 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);
+}
+
+/* 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 = 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(*(u32*)(skb->nh.raw+off+2));
+
+ if (pkt_len > skb->len - sizeof(struct ipv6hdr))
+ goto bad;
+ if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
+ if (__pskb_trim(skb,
+ pkt_len + sizeof(struct ipv6hdr)))
+ goto bad;
+ if (skb->ip_summed == CHECKSUM_HW)
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+ 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;
+ struct nf_bridge_info *nf_bridge;
+
+ 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 (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
+ if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr)))
+ goto inhdr_error;
+ if (skb->ip_summed == CHECKSUM_HW)
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+ }
+ if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
+ goto inhdr_error;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_IP6_PRE_ROUTING);
+#endif
+ if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
+ return NF_DROP;
+ setup_pre_routing(skb);
+
+ 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;
+ struct nf_bridge_info *nf_bridge;
+ struct vlan_ethhdr *hdr = vlan_eth_hdr(*pskb);
+
+ if (skb->protocol == __constant_htons(ETH_P_IPV6) || IS_VLAN_IPV6) {
+#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 == __constant_htons(ETH_P_8021Q)) {
+ skb_pull(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 != __constant_htons(ETH_P_IP) && !IS_VLAN_IP)
+ return NF_ACCEPT;
+
+ if ((skb = skb_share_check(*pskb, GFP_ATOMIC)) == NULL)
+ goto out;
+
+ if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+ skb_pull(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;
+
+ if (skb->len > len) {
+ __pskb_trim(skb, len);
+ if (skb->ip_summed == CHECKSUM_HW)
+ skb->ip_summed = CHECKSUM_NONE;
+ }
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_IP_PRE_ROUTING);
+#endif
+ if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
+ return NF_DROP;
+ setup_pre_routing(skb);
+ 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;
+ struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_BR_FORWARD);
+#endif
+
+ if (skb->protocol != __constant_htons(ETH_P_ARP) && !IS_VLAN_ARP) {
+ 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 == __constant_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 vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+ int pf;
+
+ if (!skb->nf_bridge)
+ return NF_ACCEPT;
+
+ if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
+ pf = PF_INET;
+ else
+ pf = PF_INET6;
+
+ if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+ skb_pull(*pskb, VLAN_HLEN);
+ (*pskb)->nh.raw += VLAN_HLEN;
+ }
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_BR_FORWARD);
+#endif
+ 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),
+ bridge_parent(out), 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 vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+ struct net_device **d = (struct net_device **)(skb->cb);
+
+#ifdef CONFIG_SYSCTL
+ if (!brnf_call_arptables)
+ return NF_ACCEPT;
+#endif
+
+ if (skb->protocol != __constant_htons(ETH_P_ARP)) {
+ if (!IS_VLAN_ARP)
+ return NF_ACCEPT;
+ skb_pull(*pskb, VLAN_HLEN);
+ (*pskb)->nh.raw += VLAN_HLEN;
+ }
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_BR_FORWARD);
+#endif
+
+ if (skb->nh.arph->ar_pln != 4) {
+ if (IS_VLAN_ARP) {
+ 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)
+{
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug &= ~(1 << NF_BR_LOCAL_OUT);
+#endif
+ if (skb->protocol == __constant_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;
+ struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+ int pf;
+
+ if (!skb->nf_bridge)
+ return NF_ACCEPT;
+
+ if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
+ pf = PF_INET;
+ else
+ pf = PF_INET6;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ /* Sometimes we get packets with NULL ->dst here (for example,
+ * running a dhcp client daemon triggers this). This should now
+ * be fixed, but let's keep the check around. */
+ if (skb->dst == NULL) {
+ printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
+ return NF_ACCEPT;
+ }
+#endif
+
+ 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 == __constant_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 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 == __constant_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) &&
+ has_bridge_parent(realindev))
+ realindev = bridge_parent(realindev);
+
+ NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
+ realoutdev, br_nf_local_out_finish,
+ NF_IP_PRI_BRIDGE_SABOTAGE_FORWARD + 1);
+ } else {
+#ifdef CONFIG_NETFILTER_DEBUG
+ skb->nf_debug ^= (1 << NF_IP_LOCAL_OUT);
+#endif
+
+ 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;
+}
+
+
+/* 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 vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+ 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.");
+ goto print_error;
+ }
+#endif
+
+ if (!nf_bridge)
+ return NF_ACCEPT;
+
+ if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
+ pf = PF_INET;
+ else
+ pf = PF_INET6;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+ if (skb->dst == NULL) {
+ printk(KERN_CRIT "br_netfilter: skb->dst == NULL.");
+ goto print_error;
+ }
+
+ skb->nf_debug ^= (1 << NF_IP_POST_ROUTING);
+#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 == __constant_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_dev_queue_push_xmit);
+
+ return NF_STOLEN;
+
+#ifdef CONFIG_NETFILTER_DEBUG
+print_error:
+ if (skb->dev != NULL) {
+ printk("[%s]", skb->dev->name);
+ if (has_bridge_parent(skb->dev))
+ printk("[%s]", bridge_parent(skb->dev)->name);
+ }
+ printk(" head:%p, raw:%p, data:%p\n", skb->head, skb->mac.raw,
+ skb->data);
+ 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_dev_queue_push_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;
+#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,
+ .owner = THIS_MODULE,
+ .pf = PF_INET6,
+ .hooknum = NF_IP6_LOCAL_OUT,
+ .priority = NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT, },
+ { .hook = ip_sabotage_out,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_POST_ROUTING,
+ .priority = NF_IP_PRI_FIRST, },
+ { .hook = ip_sabotage_out,
+ .owner = THIS_MODULE,
+ .pf = PF_INET6,
+ .hooknum = NF_IP6_POST_ROUTING,
+ .priority = NF_IP6_PRI_FIRST, },
+};
+
+#ifdef CONFIG_SYSCTL
+static
+int brnf_sysctl_call_tables(ctl_table *ctl, int write, struct file * filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
+
+ if (write && *(int *)(ctl->data))
+ *(int *)(ctl->data) = 1;
+ return ret;
+}
+
+static ctl_table brnf_table[] = {
+ {
+ .ctl_name = NET_BRIDGE_NF_CALL_ARPTABLES,
+ .procname = "bridge-nf-call-arptables",
+ .data = &brnf_call_arptables,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &brnf_sysctl_call_tables,
+ },
+ {
+ .ctl_name = NET_BRIDGE_NF_CALL_IPTABLES,
+ .procname = "bridge-nf-call-iptables",
+ .data = &brnf_call_iptables,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &brnf_sysctl_call_tables,
+ },
+ {
+ .ctl_name = NET_BRIDGE_NF_CALL_IP6TABLES,
+ .procname = "bridge-nf-call-ip6tables",
+ .data = &brnf_call_ip6tables,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &brnf_sysctl_call_tables,
+ },
+ {
+ .ctl_name = NET_BRIDGE_NF_FILTER_VLAN_TAGGED,
+ .procname = "bridge-nf-filter-vlan-tagged",
+ .data = &brnf_filter_vlan_tagged,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &brnf_sysctl_call_tables,
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table brnf_bridge_table[] = {
+ {
+ .ctl_name = NET_BRIDGE,
+ .procname = "bridge",
+ .mode = 0555,
+ .child = brnf_table,
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table brnf_net_table[] = {
+ {
+ .ctl_name = CTL_NET,
+ .procname = "net",
+ .mode = 0555,
+ .child = brnf_bridge_table,
+ },
+ { .ctl_name = 0 }
+};
+#endif
+
+int br_netfilter_init(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++) {
+ int ret;
+
+ if ((ret = nf_register_hook(&br_nf_ops[i])) >= 0)
+ continue;
+
+ while (i--)
+ nf_unregister_hook(&br_nf_ops[i]);
+
+ return ret;
+ }
+
+#ifdef CONFIG_SYSCTL
+ brnf_sysctl_header = register_sysctl_table(brnf_net_table, 0);
+ if (brnf_sysctl_header == NULL) {
+ printk(KERN_WARNING "br_netfilter: can't register to sysctl.\n");
+ for (i = 0; i < ARRAY_SIZE(br_nf_ops); i++)
+ nf_unregister_hook(&br_nf_ops[i]);
+ return -EFAULT;
+ }
+#endif
+
+ printk(KERN_NOTICE "Bridge firewalling registered\n");
+
+ return 0;
+}
+
+void br_netfilter_fini(void)
+{
+ int i;
+
+ for (i = ARRAY_SIZE(br_nf_ops) - 1; i >= 0; i--)
+ nf_unregister_hook(&br_nf_ops[i]);
+#ifdef CONFIG_SYSCTL
+ unregister_sysctl_table(brnf_sysctl_header);
+#endif
+}