Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1247 insertions, 0 deletions

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
new file mode 100644
index 000000000..202ad43e3
--- /dev/null
+++ b/net/bridge/br_netfilter_hooks.c
@@ -0,0 +1,1247 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Handle firewalling
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ *	Bart De Schuymer		<bdschuym@pandora.be>
+ *
+ *	Lennert dedicates this file to Kerstin Wurdinger.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.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/if_pppox.h>
+#include <linux/ppp_defs.h>
+#include <linux/netfilter_bridge.h>
+#include <uapi/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 <linux/rculist.h>
+#include <linux/inetdevice.h>
+
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/addrconf.h>
+#include <net/route.h>
+#include <net/netfilter/br_netfilter.h>
+#include <net/netns/generic.h>
+
+#include <linux/uaccess.h>
+#include "br_private.h"
+#ifdef CONFIG_SYSCTL
+#include <linux/sysctl.h>
+#endif
+
+static unsigned int brnf_net_id __read_mostly;
+
+struct brnf_net {
+	bool enabled;
+
+#ifdef CONFIG_SYSCTL
+	struct ctl_table_header *ctl_hdr;
+#endif
+
+	/* default value is 1 */
+	int call_iptables;
+	int call_ip6tables;
+	int call_arptables;
+
+	/* default value is 0 */
+	int filter_vlan_tagged;
+	int filter_pppoe_tagged;
+	int pass_vlan_indev;
+};
+
+#define IS_IP(skb) \
+	(!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
+
+#define IS_IPV6(skb) \
+	(!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
+
+#define IS_ARP(skb) \
+	(!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
+
+static inline __be16 vlan_proto(const struct sk_buff *skb)
+{
+	if (skb_vlan_tag_present(skb))
+		return skb->protocol;
+	else if (skb->protocol == htons(ETH_P_8021Q))
+		return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
+	else
+		return 0;
+}
+
+static inline bool is_vlan_ip(const struct sk_buff *skb, const struct net *net)
+{
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	return vlan_proto(skb) == htons(ETH_P_IP) && brnet->filter_vlan_tagged;
+}
+
+static inline bool is_vlan_ipv6(const struct sk_buff *skb,
+				const struct net *net)
+{
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	return vlan_proto(skb) == htons(ETH_P_IPV6) &&
+	       brnet->filter_vlan_tagged;
+}
+
+static inline bool is_vlan_arp(const struct sk_buff *skb, const struct net *net)
+{
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	return vlan_proto(skb) == htons(ETH_P_ARP) && brnet->filter_vlan_tagged;
+}
+
+static inline __be16 pppoe_proto(const struct sk_buff *skb)
+{
+	return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
+			    sizeof(struct pppoe_hdr)));
+}
+
+static inline bool is_pppoe_ip(const struct sk_buff *skb, const struct net *net)
+{
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	return skb->protocol == htons(ETH_P_PPP_SES) &&
+	       pppoe_proto(skb) == htons(PPP_IP) && brnet->filter_pppoe_tagged;
+}
+
+static inline bool is_pppoe_ipv6(const struct sk_buff *skb,
+				 const struct net *net)
+{
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	return skb->protocol == htons(ETH_P_PPP_SES) &&
+	       pppoe_proto(skb) == htons(PPP_IPV6) &&
+	       brnet->filter_pppoe_tagged;
+}
+
+/* largest possible L2 header, see br_nf_dev_queue_xmit() */
+#define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
+
+struct brnf_frag_data {
+	char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
+	u8 encap_size;
+	u8 size;
+	u16 vlan_tci;
+	__be16 vlan_proto;
+};
+
+static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage);
+
+static void nf_bridge_info_free(struct sk_buff *skb)
+{
+	skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
+}
+
+static inline struct net_device *bridge_parent(const struct net_device *dev)
+{
+	struct net_bridge_port *port;
+
+	port = br_port_get_rcu(dev);
+	return port ? port->br->dev : NULL;
+}
+
+static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
+{
+	return skb_ext_add(skb, SKB_EXT_BRIDGE_NF);
+}
+
+unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
+{
+	switch (skb->protocol) {
+	case __cpu_to_be16(ETH_P_8021Q):
+		return VLAN_HLEN;
+	case __cpu_to_be16(ETH_P_PPP_SES):
+		return PPPOE_SES_HLEN;
+	default:
+		return 0;
+	}
+}
+
+static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
+{
+	unsigned int len = nf_bridge_encap_header_len(skb);
+
+	skb_pull(skb, len);
+	skb->network_header += len;
+}
+
+static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
+{
+	unsigned int len = nf_bridge_encap_header_len(skb);
+
+	skb_pull_rcsum(skb, len);
+	skb->network_header += len;
+}
+
+/* When handing a packet over to the IP layer
+ * check whether we have a skb that is in the
+ * expected format
+ */
+
+static int br_validate_ipv4(struct net *net, struct sk_buff *skb)
+{
+	const struct iphdr *iph;
+	u32 len;
+
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto inhdr_error;
+
+	iph = ip_hdr(skb);
+
+	/* Basic sanity checks */
+	if (iph->ihl < 5 || iph->version != 4)
+		goto inhdr_error;
+
+	if (!pskb_may_pull(skb, iph->ihl*4))
+		goto inhdr_error;
+
+	iph = ip_hdr(skb);
+	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
+		goto csum_error;
+
+	len = ntohs(iph->tot_len);
+	if (skb->len < len) {
+		__IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
+		goto drop;
+	} else if (len < (iph->ihl*4))
+		goto inhdr_error;
+
+	if (pskb_trim_rcsum(skb, len)) {
+		__IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
+		goto drop;
+	}
+
+	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+	/* We should really parse IP options here but until
+	 * somebody who actually uses IP options complains to
+	 * us we'll just silently ignore the options because
+	 * we're lazy!
+	 */
+	return 0;
+
+csum_error:
+	__IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
+inhdr_error:
+	__IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
+drop:
+	return -1;
+}
+
+void nf_bridge_update_protocol(struct sk_buff *skb)
+{
+	const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+
+	switch (nf_bridge->orig_proto) {
+	case BRNF_PROTO_8021Q:
+		skb->protocol = htons(ETH_P_8021Q);
+		break;
+	case BRNF_PROTO_PPPOE:
+		skb->protocol = htons(ETH_P_PPP_SES);
+		break;
+	case BRNF_PROTO_UNCHANGED:
+		break;
+	}
+}
+
+/* Obtain the correct destination MAC address, while preserving the original
+ * source MAC address. If we already know this address, we just copy it. If we
+ * don't, we use the neighbour framework to find out. In both cases, we make
+ * sure that br_handle_frame_finish() is called afterwards.
+ */
+int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct neighbour *neigh;
+	struct dst_entry *dst;
+
+	skb->dev = bridge_parent(skb->dev);
+	if (!skb->dev)
+		goto free_skb;
+	dst = skb_dst(skb);
+	neigh = dst_neigh_lookup_skb(dst, skb);
+	if (neigh) {
+		struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+		int ret;
+
+		if ((READ_ONCE(neigh->nud_state) & NUD_CONNECTED) &&
+		    READ_ONCE(neigh->hh.hh_len)) {
+			struct net_device *br_indev;
+
+			br_indev = nf_bridge_get_physindev(skb, net);
+			if (!br_indev) {
+				neigh_release(neigh);
+				goto free_skb;
+			}
+
+			neigh_hh_bridge(&neigh->hh, skb);
+			skb->dev = br_indev;
+
+			ret = br_handle_frame_finish(net, sk, skb);
+		} else {
+			/* the neighbour function below overwrites the complete
+			 * MAC header, so we save the Ethernet source address and
+			 * protocol number.
+			 */
+			skb_copy_from_linear_data_offset(skb,
+							 -(ETH_HLEN-ETH_ALEN),
+							 nf_bridge->neigh_header,
+							 ETH_HLEN-ETH_ALEN);
+			/* tell br_dev_xmit to continue with forwarding */
+			nf_bridge->bridged_dnat = 1;
+			/* FIXME Need to refragment */
+			ret = READ_ONCE(neigh->output)(neigh, skb);
+		}
+		neigh_release(neigh);
+		return ret;
+	}
+free_skb:
+	kfree_skb(skb);
+	return 0;
+}
+
+static inline bool
+br_nf_ipv4_daddr_was_changed(const struct sk_buff *skb,
+			     const struct nf_bridge_info *nf_bridge)
+{
+	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
+ *    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's first consider the case that ip_route_input() succeeds:
+ *
+ * If the output device equals the logical bridge device the packet
+ * came in on, we can consider this bridging. The corresponding MAC
+ * address will be obtained in br_nf_pre_routing_finish_bridge.
+ * 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. For a redirected
+ * packet, ip_route_input() will give back the localhost as output device,
+ * which differs from the bridge device.
+ *
+ * Let's 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.
+ * If IP forwarding is disabled, ip_route_input() will fail, while
+ * ip_route_output_key() can 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 enabled. If the output device equals the logical bridge
+ * device, we proceed as if ip_route_input() succeeded. If it differs from the
+ * logical bridge port or if ip_route_output_key() fails we drop the packet.
+ */
+static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev, *br_indev;
+	struct iphdr *iph = ip_hdr(skb);
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct rtable *rt;
+	int err;
+
+	br_indev = nf_bridge_get_physindev(skb, net);
+	if (!br_indev) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
+
+	if (nf_bridge->pkt_otherhost) {
+		skb->pkt_type = PACKET_OTHERHOST;
+		nf_bridge->pkt_otherhost = false;
+	}
+	nf_bridge->in_prerouting = 0;
+	if (br_nf_ipv4_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);
+
+			/* 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;
+
+			rt = ip_route_output(net, iph->daddr, 0,
+					     RT_TOS(iph->tos), 0);
+			if (!IS_ERR(rt)) {
+				/* - Bridged-and-DNAT'ed traffic doesn't
+				 *   require ip_forwarding. */
+				if (rt->dst.dev == dev) {
+					skb_dst_drop(skb);
+					skb_dst_set(skb, &rt->dst);
+					goto bridged_dnat;
+				}
+				ip_rt_put(rt);
+			}
+free_skb:
+			kfree_skb(skb);
+			return 0;
+		} else {
+			if (skb_dst(skb)->dev == dev) {
+bridged_dnat:
+				skb->dev = br_indev;
+				nf_bridge_update_protocol(skb);
+				nf_bridge_push_encap_header(skb);
+				br_nf_hook_thresh(NF_BR_PRE_ROUTING,
+						  net, sk, skb, skb->dev,
+						  NULL,
+						  br_nf_pre_routing_finish_bridge);
+				return 0;
+			}
+			ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
+			skb->pkt_type = PACKET_HOST;
+		}
+	} else {
+		rt = bridge_parent_rtable(br_indev);
+		if (!rt) {
+			kfree_skb(skb);
+			return 0;
+		}
+		skb_dst_drop(skb);
+		skb_dst_set_noref(skb, &rt->dst);
+	}
+
+	skb->dev = br_indev;
+	nf_bridge_update_protocol(skb);
+	nf_bridge_push_encap_header(skb);
+	br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
+			  br_handle_frame_finish);
+	return 0;
+}
+
+static struct net_device *brnf_get_logical_dev(struct sk_buff *skb,
+					       const struct net_device *dev,
+					       const struct net *net)
+{
+	struct net_device *vlan, *br;
+	struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+	br = bridge_parent(dev);
+
+	if (brnet->pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
+		return br;
+
+	vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
+				    skb_vlan_tag_get(skb) & VLAN_VID_MASK);
+
+	return vlan ? vlan : br;
+}
+
+/* Some common code for IPv4/IPv6 */
+struct net_device *setup_pre_routing(struct sk_buff *skb, const struct net *net)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+
+	if (skb->pkt_type == PACKET_OTHERHOST) {
+		skb->pkt_type = PACKET_HOST;
+		nf_bridge->pkt_otherhost = true;
+	}
+
+	nf_bridge->in_prerouting = 1;
+	nf_bridge->physinif = skb->dev->ifindex;
+	skb->dev = brnf_get_logical_dev(skb, skb->dev, net);
+
+	if (skb->protocol == htons(ETH_P_8021Q))
+		nf_bridge->orig_proto = BRNF_PROTO_8021Q;
+	else if (skb->protocol == htons(ETH_P_PPP_SES))
+		nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
+
+	/* Must drop socket now because of tproxy. */
+	skb_orphan(skb);
+	return skb->dev;
+}
+
+/* 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(void *priv,
+				      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);
+	struct brnf_net *brnet;
+
+	if (unlikely(!pskb_may_pull(skb, len)))
+		return NF_DROP;
+
+	p = br_port_get_rcu(state->in);
+	if (p == NULL)
+		return NF_DROP;
+	br = p->br;
+
+	brnet = net_generic(state->net, brnf_net_id);
+	if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
+	    is_pppoe_ipv6(skb, state->net)) {
+		if (!brnet->call_ip6tables &&
+		    !br_opt_get(br, BROPT_NF_CALL_IP6TABLES))
+			return NF_ACCEPT;
+		if (!ipv6_mod_enabled()) {
+			pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
+			return NF_DROP;
+		}
+
+		nf_bridge_pull_encap_header_rcsum(skb);
+		return br_nf_pre_routing_ipv6(priv, skb, state);
+	}
+
+	if (!brnet->call_iptables && !br_opt_get(br, BROPT_NF_CALL_IPTABLES))
+		return NF_ACCEPT;
+
+	if (!IS_IP(skb) && !is_vlan_ip(skb, state->net) &&
+	    !is_pppoe_ip(skb, state->net))
+		return NF_ACCEPT;
+
+	nf_bridge_pull_encap_header_rcsum(skb);
+
+	if (br_validate_ipv4(state->net, skb))
+		return NF_DROP;
+
+	if (!nf_bridge_alloc(skb))
+		return NF_DROP;
+	if (!setup_pre_routing(skb, state->net))
+		return NF_DROP;
+
+	nf_bridge = nf_bridge_info_get(skb);
+	nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
+
+	skb->protocol = htons(ETH_P_IP);
+	skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
+
+	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
+		skb->dev, NULL,
+		br_nf_pre_routing_finish);
+
+	return NF_STOLEN;
+}
+
+
+/* PF_BRIDGE/FORWARD *************************************************/
+static int br_nf_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct net_device *in;
+
+	if (!IS_ARP(skb) && !is_vlan_arp(skb, net)) {
+
+		if (skb->protocol == htons(ETH_P_IP))
+			nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
+
+		if (skb->protocol == htons(ETH_P_IPV6))
+			nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
+
+		in = nf_bridge_get_physindev(skb, net);
+		if (!in) {
+			kfree_skb(skb);
+			return 0;
+		}
+		if (nf_bridge->pkt_otherhost) {
+			skb->pkt_type = PACKET_OTHERHOST;
+			nf_bridge->pkt_otherhost = false;
+		}
+		nf_bridge_update_protocol(skb);
+	} else {
+		in = *((struct net_device **)(skb->cb));
+	}
+	nf_bridge_push_encap_header(skb);
+
+	br_nf_hook_thresh(NF_BR_FORWARD, net, sk, skb, in, skb->dev,
+			  br_forward_finish);
+	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(void *priv,
+				     struct sk_buff *skb,
+				     const struct nf_hook_state *state)
+{
+	struct nf_bridge_info *nf_bridge;
+	struct net_device *parent;
+	u_int8_t pf;
+
+	nf_bridge = nf_bridge_info_get(skb);
+	if (!nf_bridge)
+		return NF_ACCEPT;
+
+	/* Need exclusive nf_bridge_info since we might have multiple
+	 * different physoutdevs. */
+	if (!nf_bridge_unshare(skb))
+		return NF_DROP;
+
+	nf_bridge = nf_bridge_info_get(skb);
+	if (!nf_bridge)
+		return NF_DROP;
+
+	parent = bridge_parent(state->out);
+	if (!parent)
+		return NF_DROP;
+
+	if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
+	    is_pppoe_ip(skb, state->net))
+		pf = NFPROTO_IPV4;
+	else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
+		 is_pppoe_ipv6(skb, state->net))
+		pf = NFPROTO_IPV6;
+	else
+		return NF_ACCEPT;
+
+	nf_bridge_pull_encap_header(skb);
+
+	if (skb->pkt_type == PACKET_OTHERHOST) {
+		skb->pkt_type = PACKET_HOST;
+		nf_bridge->pkt_otherhost = true;
+	}
+
+	if (pf == NFPROTO_IPV4) {
+		if (br_validate_ipv4(state->net, skb))
+			return NF_DROP;
+		IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
+	}
+
+	if (pf == NFPROTO_IPV6) {
+		if (br_validate_ipv6(state->net, skb))
+			return NF_DROP;
+		IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
+	}
+
+	nf_bridge->physoutdev = skb->dev;
+	if (pf == NFPROTO_IPV4)
+		skb->protocol = htons(ETH_P_IP);
+	else
+		skb->protocol = htons(ETH_P_IPV6);
+
+	NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
+		brnf_get_logical_dev(skb, state->in, state->net),
+		parent,	br_nf_forward_finish);
+
+	return NF_STOLEN;
+}
+
+static unsigned int br_nf_forward_arp(void *priv,
+				      struct sk_buff *skb,
+				      const struct nf_hook_state *state)
+{
+	struct net_bridge_port *p;
+	struct net_bridge *br;
+	struct net_device **d = (struct net_device **)(skb->cb);
+	struct brnf_net *brnet;
+
+	p = br_port_get_rcu(state->out);
+	if (p == NULL)
+		return NF_ACCEPT;
+	br = p->br;
+
+	brnet = net_generic(state->net, brnf_net_id);
+	if (!brnet->call_arptables && !br_opt_get(br, BROPT_NF_CALL_ARPTABLES))
+		return NF_ACCEPT;
+
+	if (!IS_ARP(skb)) {
+		if (!is_vlan_arp(skb, state->net))
+			return NF_ACCEPT;
+		nf_bridge_pull_encap_header(skb);
+	}
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(struct arphdr))))
+		return NF_DROP;
+
+	if (arp_hdr(skb)->ar_pln != 4) {
+		if (is_vlan_arp(skb, state->net))
+			nf_bridge_push_encap_header(skb);
+		return NF_ACCEPT;
+	}
+	*d = state->in;
+	NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
+		state->in, state->out, br_nf_forward_finish);
+
+	return NF_STOLEN;
+}
+
+static int br_nf_push_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct brnf_frag_data *data;
+	int err;
+
+	data = this_cpu_ptr(&brnf_frag_data_storage);
+	err = skb_cow_head(skb, data->size);
+
+	if (err) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	if (data->vlan_proto)
+		__vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci);
+
+	skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
+	__skb_push(skb, data->encap_size);
+
+	nf_bridge_info_free(skb);
+	return br_dev_queue_push_xmit(net, sk, skb);
+}
+
+static int
+br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
+		  int (*output)(struct net *, struct sock *, struct sk_buff *))
+{
+	unsigned int mtu = ip_skb_dst_mtu(sk, skb);
+	struct iphdr *iph = ip_hdr(skb);
+
+	if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+		     (IPCB(skb)->frag_max_size &&
+		      IPCB(skb)->frag_max_size > mtu))) {
+		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
+		kfree_skb(skb);
+		return -EMSGSIZE;
+	}
+
+	return ip_do_fragment(net, sk, skb, output);
+}
+
+static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
+{
+	const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+
+	if (nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
+		return PPPOE_SES_HLEN;
+	return 0;
+}
+
+static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	unsigned int mtu, mtu_reserved;
+
+	mtu_reserved = nf_bridge_mtu_reduction(skb);
+	mtu = skb->dev->mtu;
+
+	if (nf_bridge->pkt_otherhost) {
+		skb->pkt_type = PACKET_OTHERHOST;
+		nf_bridge->pkt_otherhost = false;
+	}
+
+	if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
+		mtu = nf_bridge->frag_max_size;
+
+	nf_bridge_update_protocol(skb);
+	nf_bridge_push_encap_header(skb);
+
+	if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
+		nf_bridge_info_free(skb);
+		return br_dev_queue_push_xmit(net, sk, skb);
+	}
+
+	/* This is wrong! We should preserve the original fragment
+	 * boundaries by preserving frag_list rather than refragmenting.
+	 */
+	if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) &&
+	    skb->protocol == htons(ETH_P_IP)) {
+		struct brnf_frag_data *data;
+
+		if (br_validate_ipv4(net, skb))
+			goto drop;
+
+		IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
+
+		data = this_cpu_ptr(&brnf_frag_data_storage);
+
+		if (skb_vlan_tag_present(skb)) {
+			data->vlan_tci = skb->vlan_tci;
+			data->vlan_proto = skb->vlan_proto;
+		} else {
+			data->vlan_proto = 0;
+		}
+
+		data->encap_size = nf_bridge_encap_header_len(skb);
+		data->size = ETH_HLEN + data->encap_size;
+
+		skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
+						 data->size);
+
+		return br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit);
+	}
+	if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) &&
+	    skb->protocol == htons(ETH_P_IPV6)) {
+		const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
+		struct brnf_frag_data *data;
+
+		if (br_validate_ipv6(net, skb))
+			goto drop;
+
+		IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
+
+		data = this_cpu_ptr(&brnf_frag_data_storage);
+		data->encap_size = nf_bridge_encap_header_len(skb);
+		data->size = ETH_HLEN + data->encap_size;
+
+		skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
+						 data->size);
+
+		if (v6ops)
+			return v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit);
+
+		kfree_skb(skb);
+		return -EMSGSIZE;
+	}
+	nf_bridge_info_free(skb);
+	return br_dev_queue_push_xmit(net, sk, skb);
+ drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+/* PF_BRIDGE/POST_ROUTING ********************************************/
+static unsigned int br_nf_post_routing(void *priv,
+				       struct sk_buff *skb,
+				       const struct nf_hook_state *state)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct net_device *realoutdev = bridge_parent(skb->dev);
+	u_int8_t pf;
+
+	/* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
+	 * on a bridge, but was delivered locally and is now being routed:
+	 *
+	 * POST_ROUTING was already invoked from the ip stack.
+	 */
+	if (!nf_bridge || !nf_bridge->physoutdev)
+		return NF_ACCEPT;
+
+	if (!realoutdev)
+		return NF_DROP;
+
+	if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
+	    is_pppoe_ip(skb, state->net))
+		pf = NFPROTO_IPV4;
+	else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
+		 is_pppoe_ipv6(skb, state->net))
+		pf = NFPROTO_IPV6;
+	else
+		return NF_ACCEPT;
+
+	if (skb->pkt_type == PACKET_OTHERHOST) {
+		skb->pkt_type = PACKET_HOST;
+		nf_bridge->pkt_otherhost = true;
+	}
+
+	nf_bridge_pull_encap_header(skb);
+	if (pf == NFPROTO_IPV4)
+		skb->protocol = htons(ETH_P_IP);
+	else
+		skb->protocol = htons(ETH_P_IPV6);
+
+	NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
+		NULL, realoutdev,
+		br_nf_dev_queue_xmit);
+
+	return NF_STOLEN;
+}
+
+/* IP/SABOTAGE *****************************************************/
+/* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
+ * for the second time. */
+static unsigned int ip_sabotage_in(void *priv,
+				   struct sk_buff *skb,
+				   const struct nf_hook_state *state)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+
+	if (nf_bridge) {
+		if (nf_bridge->sabotage_in_done)
+			return NF_ACCEPT;
+
+		if (!nf_bridge->in_prerouting &&
+		    !netif_is_l3_master(skb->dev) &&
+		    !netif_is_l3_slave(skb->dev)) {
+			nf_bridge->sabotage_in_done = 1;
+			state->okfn(state->net, state->sk, skb);
+			return NF_STOLEN;
+		}
+	}
+
+	return NF_ACCEPT;
+}
+
+/* This is called when br_netfilter has called into iptables/netfilter,
+ * and DNAT has taken place on a bridge-forwarded packet.
+ *
+ * neigh->output has created a new MAC header, with local br0 MAC
+ * as saddr.
+ *
+ * This restores the original MAC saddr of the bridged packet
+ * before invoking bridge forward logic to transmit the packet.
+ */
+static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
+{
+	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct net_device *br_indev;
+
+	br_indev = nf_bridge_get_physindev(skb, dev_net(skb->dev));
+	if (!br_indev) {
+		kfree_skb(skb);
+		return;
+	}
+
+	skb_pull(skb, ETH_HLEN);
+	nf_bridge->bridged_dnat = 0;
+
+	BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
+
+	skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
+				       nf_bridge->neigh_header,
+				       ETH_HLEN - ETH_ALEN);
+	skb->dev = br_indev;
+
+	nf_bridge->physoutdev = NULL;
+	br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
+}
+
+static int br_nf_dev_xmit(struct sk_buff *skb)
+{
+	const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+
+	if (nf_bridge && nf_bridge->bridged_dnat) {
+		br_nf_pre_routing_finish_bridge_slow(skb);
+		return 1;
+	}
+	return 0;
+}
+
+static const struct nf_br_ops br_ops = {
+	.br_dev_xmit_hook =	br_nf_dev_xmit,
+};
+
+/* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
+ * br_dev_queue_push_xmit is called afterwards */
+static const struct nf_hook_ops br_nf_ops[] = {
+	{
+		.hook = br_nf_pre_routing,
+		.pf = NFPROTO_BRIDGE,
+		.hooknum = NF_BR_PRE_ROUTING,
+		.priority = NF_BR_PRI_BRNF,
+	},
+	{
+		.hook = br_nf_forward_ip,
+		.pf = NFPROTO_BRIDGE,
+		.hooknum = NF_BR_FORWARD,
+		.priority = NF_BR_PRI_BRNF - 1,
+	},
+	{
+		.hook = br_nf_forward_arp,
+		.pf = NFPROTO_BRIDGE,
+		.hooknum = NF_BR_FORWARD,
+		.priority = NF_BR_PRI_BRNF,
+	},
+	{
+		.hook = br_nf_post_routing,
+		.pf = NFPROTO_BRIDGE,
+		.hooknum = NF_BR_POST_ROUTING,
+		.priority = NF_BR_PRI_LAST,
+	},
+	{
+		.hook = ip_sabotage_in,
+		.pf = NFPROTO_IPV4,
+		.hooknum = NF_INET_PRE_ROUTING,
+		.priority = NF_IP_PRI_FIRST,
+	},
+	{
+		.hook = ip_sabotage_in,
+		.pf = NFPROTO_IPV6,
+		.hooknum = NF_INET_PRE_ROUTING,
+		.priority = NF_IP6_PRI_FIRST,
+	},
+};
+
+static int brnf_device_event(struct notifier_block *unused, unsigned long event,
+			     void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct brnf_net *brnet;
+	struct net *net;
+	int ret;
+
+	if (event != NETDEV_REGISTER || !netif_is_bridge_master(dev))
+		return NOTIFY_DONE;
+
+	ASSERT_RTNL();
+
+	net = dev_net(dev);
+	brnet = net_generic(net, brnf_net_id);
+	if (brnet->enabled)
+		return NOTIFY_OK;
+
+	ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
+	if (ret)
+		return NOTIFY_BAD;
+
+	brnet->enabled = true;
+	return NOTIFY_OK;
+}
+
+static struct notifier_block brnf_notifier __read_mostly = {
+	.notifier_call = brnf_device_event,
+};
+
+/* recursively invokes nf_hook_slow (again), skipping already-called
+ * hooks (< NF_BR_PRI_BRNF).
+ *
+ * Called with rcu read lock held.
+ */
+int br_nf_hook_thresh(unsigned int hook, struct net *net,
+		      struct sock *sk, struct sk_buff *skb,
+		      struct net_device *indev,
+		      struct net_device *outdev,
+		      int (*okfn)(struct net *, struct sock *,
+				  struct sk_buff *))
+{
+	const struct nf_hook_entries *e;
+	struct nf_hook_state state;
+	struct nf_hook_ops **ops;
+	unsigned int i;
+	int ret;
+
+	e = rcu_dereference(net->nf.hooks_bridge[hook]);
+	if (!e)
+		return okfn(net, sk, skb);
+
+	ops = nf_hook_entries_get_hook_ops(e);
+	for (i = 0; i < e->num_hook_entries; i++) {
+		/* These hooks have already been called */
+		if (ops[i]->priority < NF_BR_PRI_BRNF)
+			continue;
+
+		/* These hooks have not been called yet, run them. */
+		if (ops[i]->priority > NF_BR_PRI_BRNF)
+			break;
+
+		/* take a closer look at NF_BR_PRI_BRNF. */
+		if (ops[i]->hook == br_nf_pre_routing) {
+			/* This hook diverted the skb to this function,
+			 * hooks after this have not been run yet.
+			 */
+			i++;
+			break;
+		}
+	}
+
+	nf_hook_state_init(&state, hook, NFPROTO_BRIDGE, indev, outdev,
+			   sk, net, okfn);
+
+	ret = nf_hook_slow(skb, &state, e, i);
+	if (ret == 1)
+		ret = okfn(net, sk, skb);
+
+	return ret;
+}
+
+#ifdef CONFIG_SYSCTL
+static
+int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,
+			    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret;
+
+	ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+
+	if (write && *(int *)(ctl->data))
+		*(int *)(ctl->data) = 1;
+	return ret;
+}
+
+static struct ctl_table brnf_table[] = {
+	{
+		.procname	= "bridge-nf-call-arptables",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{
+		.procname	= "bridge-nf-call-iptables",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{
+		.procname	= "bridge-nf-call-ip6tables",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{
+		.procname	= "bridge-nf-filter-vlan-tagged",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{
+		.procname	= "bridge-nf-filter-pppoe-tagged",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{
+		.procname	= "bridge-nf-pass-vlan-input-dev",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= brnf_sysctl_call_tables,
+	},
+	{ }
+};
+
+static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
+{
+	brnf->call_iptables = 1;
+	brnf->call_ip6tables = 1;
+	brnf->call_arptables = 1;
+	brnf->filter_vlan_tagged = 0;
+	brnf->filter_pppoe_tagged = 0;
+	brnf->pass_vlan_indev = 0;
+}
+
+static int br_netfilter_sysctl_init_net(struct net *net)
+{
+	struct ctl_table *table = brnf_table;
+	struct brnf_net *brnet;
+
+	if (!net_eq(net, &init_net)) {
+		table = kmemdup(table, sizeof(brnf_table), GFP_KERNEL);
+		if (!table)
+			return -ENOMEM;
+	}
+
+	brnet = net_generic(net, brnf_net_id);
+	table[0].data = &brnet->call_arptables;
+	table[1].data = &brnet->call_iptables;
+	table[2].data = &brnet->call_ip6tables;
+	table[3].data = &brnet->filter_vlan_tagged;
+	table[4].data = &brnet->filter_pppoe_tagged;
+	table[5].data = &brnet->pass_vlan_indev;
+
+	br_netfilter_sysctl_default(brnet);
+
+	brnet->ctl_hdr = register_net_sysctl(net, "net/bridge", table);
+	if (!brnet->ctl_hdr) {
+		if (!net_eq(net, &init_net))
+			kfree(table);
+
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void br_netfilter_sysctl_exit_net(struct net *net,
+					 struct brnf_net *brnet)
+{
+	struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
+
+	unregister_net_sysctl_table(brnet->ctl_hdr);
+	if (!net_eq(net, &init_net))
+		kfree(table);
+}
+
+static int __net_init brnf_init_net(struct net *net)
+{
+	return br_netfilter_sysctl_init_net(net);
+}
+#endif
+
+static void __net_exit brnf_exit_net(struct net *net)
+{
+	struct brnf_net *brnet;
+
+	brnet = net_generic(net, brnf_net_id);
+	if (brnet->enabled) {
+		nf_unregister_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
+		brnet->enabled = false;
+	}
+
+#ifdef CONFIG_SYSCTL
+	br_netfilter_sysctl_exit_net(net, brnet);
+#endif
+}
+
+static struct pernet_operations brnf_net_ops __read_mostly = {
+#ifdef CONFIG_SYSCTL
+	.init = brnf_init_net,
+#endif
+	.exit = brnf_exit_net,
+	.id   = &brnf_net_id,
+	.size = sizeof(struct brnf_net),
+};
+
+static int __init br_netfilter_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&brnf_net_ops);
+	if (ret < 0)
+		return ret;
+
+	ret = register_netdevice_notifier(&brnf_notifier);
+	if (ret < 0) {
+		unregister_pernet_subsys(&brnf_net_ops);
+		return ret;
+	}
+
+	RCU_INIT_POINTER(nf_br_ops, &br_ops);
+	printk(KERN_NOTICE "Bridge firewalling registered\n");
+	return 0;
+}
+
+static void __exit br_netfilter_fini(void)
+{
+	RCU_INIT_POINTER(nf_br_ops, NULL);
+	unregister_netdevice_notifier(&brnf_notifier);
+	unregister_pernet_subsys(&brnf_net_ops);
+}
+
+module_init(br_netfilter_init);
+module_exit(br_netfilter_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
+MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
+MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");