net/bridge/br_arp_nd_proxy.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Handle bridge arp/nd proxy/suppress
  *
  *  Copyright (C) 2017 Cumulus Networks
  *  Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com>
  *
  *  Authors:
  *	Roopa Prabhu <roopa@cumulusnetworks.com>
  */

 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/neighbour.h>
 #include <net/arp.h>
 #include <linux/if_vlan.h>
 #include <linux/inetdevice.h>
 #include <net/addrconf.h>
 #include <net/ipv6_stubs.h>
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ip6_checksum.h>
 #endif

 #include "br_private.h"

 void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
 {
 	struct net_bridge_port *p;
 	bool neigh_suppress = false;

 	list_for_each_entry(p, &br->port_list, list) {
 		if (p->flags & BR_NEIGH_SUPPRESS) {
 			neigh_suppress = true;
 			break;
 		}
 	}

 	br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress);
 }

 #if IS_ENABLED(CONFIG_INET)
 static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p,
 			struct net_device *dev, __be32 dest_ip, __be32 src_ip,
 			const unsigned char *dest_hw,
 			const unsigned char *src_hw,
 			const unsigned char *target_hw,
 			__be16 vlan_proto, u16 vlan_tci)
 {
 	struct net_bridge_vlan_group *vg;
 	struct sk_buff *skb;
 	u16 pvid;

 	netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n",
 		   dev->name, &dest_ip, dest_hw, &src_ip, src_hw);

 	if (!vlan_tci) {
 		arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
 			 dest_hw, src_hw, target_hw);
 		return;
 	}

 	skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
 			 dest_hw, src_hw, target_hw);
 	if (!skb)
 		return;

 	if (p)
 		vg = nbp_vlan_group_rcu(p);
 	else
 		vg = br_vlan_group_rcu(br);
 	pvid = br_get_pvid(vg);
 	if (pvid == (vlan_tci & VLAN_VID_MASK))
 		vlan_tci = 0;

 	if (vlan_tci)
 		__vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);

 	if (p) {
 		arp_xmit(skb);
 	} else {
 		skb_reset_mac_header(skb);
 		__skb_pull(skb, skb_network_offset(skb));
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 		skb->pkt_type = PACKET_HOST;

 		netif_rx_ni(skb);
 	}
 }

 static int br_chk_addr_ip(struct net_device *dev, void *data)
 {
 	__be32 ip = *(__be32 *)data;
 	struct in_device *in_dev;
 	__be32 addr = 0;

 	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev)
 		addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip,
 					 RT_SCOPE_HOST);

 	if (addr == ip)
 		return 1;

 	return 0;
 }

 static bool br_is_local_ip(struct net_device *dev, __be32 ip)
 {
 	if (br_chk_addr_ip(dev, &ip))
 		return true;

 	/* check if ip is configured on upper dev */
 	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &ip))
 		return true;

 	return false;
 }

 void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
 			      u16 vid, struct net_bridge_port *p)
 {
 	struct net_device *dev = br->dev;
 	struct net_device *vlandev = dev;
 	struct neighbour *n;
 	struct arphdr *parp;
 	u8 *arpptr, *sha;
 	__be32 sip, tip;

 	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;

 	if ((dev->flags & IFF_NOARP) ||
 	    !pskb_may_pull(skb, arp_hdr_len(dev)))
 		return;

 	parp = arp_hdr(skb);

 	if (parp->ar_pro != htons(ETH_P_IP) ||
 	    parp->ar_hln != dev->addr_len ||
 	    parp->ar_pln != 4)
 		return;

 	arpptr = (u8 *)parp + sizeof(struct arphdr);
 	sha = arpptr;
 	arpptr += dev->addr_len;	/* sha */
 	memcpy(&sip, arpptr, sizeof(sip));
 	arpptr += sizeof(sip);
 	arpptr += dev->addr_len;	/* tha */
 	memcpy(&tip, arpptr, sizeof(tip));

 	if (ipv4_is_loopback(tip) ||
 	    ipv4_is_multicast(tip))
 		return;

 	if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
 		if (p && (p->flags & BR_NEIGH_SUPPRESS))
 			return;
 		if (parp->ar_op != htons(ARPOP_RREQUEST) &&
 		    parp->ar_op != htons(ARPOP_RREPLY) &&
 		    (ipv4_is_zeronet(sip) || sip == tip)) {
 			/* prevent flooding to neigh suppress ports */
 			BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 			return;
 		}
 	}

 	if (parp->ar_op != htons(ARPOP_REQUEST))
 		return;

 	if (vid != 0) {
 		vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
 						   vid);
 		if (!vlandev)
 			return;
 	}

 	if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
 	    br_is_local_ip(vlandev, tip)) {
 		/* its our local ip, so don't proxy reply
 		 * and don't forward to neigh suppress ports
 		 */
 		BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		return;
 	}

 	n = neigh_lookup(&arp_tbl, &tip, vlandev);
 	if (n) {
 		struct net_bridge_fdb_entry *f;

 		if (!(n->nud_state & NUD_VALID)) {
 			neigh_release(n);
 			return;
 		}

 		f = br_fdb_find_rcu(br, n->ha, vid);
 		if (f) {
 			bool replied = false;

 			if ((p && (p->flags & BR_PROXYARP)) ||
 			    (f->dst && (f->dst->flags & (BR_PROXYARP_WIFI |
 							 BR_NEIGH_SUPPRESS)))) {
 				if (!vid)
 					br_arp_send(br, p, skb->dev, sip, tip,
 						    sha, n->ha, sha, 0, 0);
 				else
 					br_arp_send(br, p, skb->dev, sip, tip,
 						    sha, n->ha, sha,
 						    skb->vlan_proto,
 						    skb_vlan_tag_get(skb));
 				replied = true;
 			}

 			/* If we have replied or as long as we know the
 			 * mac, indicate to arp replied
 			 */
 			if (replied ||
 			    br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
 				BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		}

 		neigh_release(n);
 	}
 }
 #endif

 #if IS_ENABLED(CONFIG_IPV6)
 struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *msg)
 {
 	struct nd_msg *m;

 	m = skb_header_pointer(skb, skb_network_offset(skb) +
 			       sizeof(struct ipv6hdr), sizeof(*msg), msg);
 	if (!m)
 		return NULL;

 	if (m->icmph.icmp6_code != 0 ||
 	    (m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION &&
 	     m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT))
 		return NULL;

 	return m;
 }

 static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p,
 		       struct sk_buff *request, struct neighbour *n,
 		       __be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns)
 {
 	struct net_device *dev = request->dev;
 	struct net_bridge_vlan_group *vg;
 	struct sk_buff *reply;
 	struct nd_msg *na;
 	struct ipv6hdr *pip6;
 	int na_olen = 8; /* opt hdr + ETH_ALEN for target */
 	int ns_olen;
 	int i, len;
 	u8 *daddr;
 	u16 pvid;

 	if (!dev)
 		return;

 	len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
 		sizeof(*na) + na_olen + dev->needed_tailroom;

 	reply = alloc_skb(len, GFP_ATOMIC);
 	if (!reply)
 		return;

 	reply->protocol = htons(ETH_P_IPV6);
 	reply->dev = dev;
 	skb_reserve(reply, LL_RESERVED_SPACE(dev));
 	skb_push(reply, sizeof(struct ethhdr));
 	skb_set_mac_header(reply, 0);

 	daddr = eth_hdr(request)->h_source;

 	/* Do we need option processing ? */
 	ns_olen = request->len - (skb_network_offset(request) +
 				  sizeof(struct ipv6hdr)) - sizeof(*ns);
 	for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) {
 		if (!ns->opt[i + 1]) {
 			kfree_skb(reply);
 			return;
 		}
 		if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
 			daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
 			break;
 		}
 	}

 	/* Ethernet header */
 	ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
 	ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
 	eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
 	reply->protocol = htons(ETH_P_IPV6);

 	skb_pull(reply, sizeof(struct ethhdr));
 	skb_set_network_header(reply, 0);
 	skb_put(reply, sizeof(struct ipv6hdr));

 	/* IPv6 header */
 	pip6 = ipv6_hdr(reply);
 	memset(pip6, 0, sizeof(struct ipv6hdr));
 	pip6->version = 6;
 	pip6->priority = ipv6_hdr(request)->priority;
 	pip6->nexthdr = IPPROTO_ICMPV6;
 	pip6->hop_limit = 255;
 	pip6->daddr = ipv6_hdr(request)->saddr;
 	pip6->saddr = *(struct in6_addr *)n->primary_key;

 	skb_pull(reply, sizeof(struct ipv6hdr));
 	skb_set_transport_header(reply, 0);

 	na = (struct nd_msg *)skb_put(reply, sizeof(*na) + na_olen);

 	/* Neighbor Advertisement */
 	memset(na, 0, sizeof(*na) + na_olen);
 	na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 	na->icmph.icmp6_router = (n->flags & NTF_ROUTER) ? 1 : 0;
 	na->icmph.icmp6_override = 1;
 	na->icmph.icmp6_solicited = 1;
 	na->target = ns->target;
 	ether_addr_copy(&na->opt[2], n->ha);
 	na->opt[0] = ND_OPT_TARGET_LL_ADDR;
 	na->opt[1] = na_olen >> 3;

 	na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
 						&pip6->daddr,
 						sizeof(*na) + na_olen,
 						IPPROTO_ICMPV6,
 						csum_partial(na, sizeof(*na) + na_olen, 0));

 	pip6->payload_len = htons(sizeof(*na) + na_olen);

 	skb_push(reply, sizeof(struct ipv6hdr));
 	skb_push(reply, sizeof(struct ethhdr));

 	reply->ip_summed = CHECKSUM_UNNECESSARY;

 	if (p)
 		vg = nbp_vlan_group_rcu(p);
 	else
 		vg = br_vlan_group_rcu(br);
 	pvid = br_get_pvid(vg);
 	if (pvid == (vlan_tci & VLAN_VID_MASK))
 		vlan_tci = 0;

 	if (vlan_tci)
 		__vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci);

 	netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n",
 		   dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha);

 	if (p) {
 		dev_queue_xmit(reply);
 	} else {
 		skb_reset_mac_header(reply);
 		__skb_pull(reply, skb_network_offset(reply));
 		reply->ip_summed = CHECKSUM_UNNECESSARY;
 		reply->pkt_type = PACKET_HOST;

 		netif_rx_ni(reply);
 	}
 }

 static int br_chk_addr_ip6(struct net_device *dev, void *data)
 {
 	struct in6_addr *addr = (struct in6_addr *)data;

 	if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
 		return 1;

 	return 0;
 }

 static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr)

 {
 	if (br_chk_addr_ip6(dev, addr))
 		return true;

 	/* check if ip is configured on upper dev */
 	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, addr))
 		return true;

 	return false;
 }

 void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
 		       u16 vid, struct net_bridge_port *p, struct nd_msg *msg)
 {
 	struct net_device *dev = br->dev;
 	struct net_device *vlandev = NULL;
 	struct in6_addr *saddr, *daddr;
 	struct ipv6hdr *iphdr;
 	struct neighbour *n;

 	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;

 	if (p && (p->flags & BR_NEIGH_SUPPRESS))
 		return;

 	if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
 	    !msg->icmph.icmp6_solicited) {
 		/* prevent flooding to neigh suppress ports */
 		BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		return;
 	}

 	if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 		return;

 	iphdr = ipv6_hdr(skb);
 	saddr = &iphdr->saddr;
 	daddr = &iphdr->daddr;

 	if (ipv6_addr_any(saddr) || !ipv6_addr_cmp(saddr, daddr)) {
 		/* prevent flooding to neigh suppress ports */
 		BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		return;
 	}

 	if (vid != 0) {
 		/* build neigh table lookup on the vlan device */
 		vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
 						   vid);
 		if (!vlandev)
 			return;
 	} else {
 		vlandev = dev;
 	}

 	if (br_is_local_ip6(vlandev, &msg->target)) {
 		/* its our own ip, so don't proxy reply
 		 * and don't forward to arp suppress ports
 		 */
 		BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		return;
 	}

 	n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
 	if (n) {
 		struct net_bridge_fdb_entry *f;

 		if (!(n->nud_state & NUD_VALID)) {
 			neigh_release(n);
 			return;
 		}

 		f = br_fdb_find_rcu(br, n->ha, vid);
 		if (f) {
 			bool replied = false;

 			if (f->dst && (f->dst->flags & BR_NEIGH_SUPPRESS)) {
 				if (vid != 0)
 					br_nd_send(br, p, skb, n,
 						   skb->vlan_proto,
 						   skb_vlan_tag_get(skb), msg);
 				else
 					br_nd_send(br, p, skb, n, 0, 0, msg);
 				replied = true;
 			}

 			/* If we have replied or as long as we know the
 			 * mac, indicate to NEIGH_SUPPRESS ports that we
 			 * have replied
 			 */
 			if (replied ||
 			    br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
 				BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
 		}
 		neigh_release(n);
 	}
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Handle bridge arp/nd proxy/suppress
	*
	* Copyright (C) 2017 Cumulus Networks
	* Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com>
	*
	* Authors:
	* Roopa Prabhu <roopa@cumulusnetworks.com>
	*/

	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/neighbour.h>
	#include <net/arp.h>
	#include <linux/if_vlan.h>
	#include <linux/inetdevice.h>
	#include <net/addrconf.h>
	#include <net/ipv6_stubs.h>
	#if IS_ENABLED(CONFIG_IPV6)
	#include <net/ip6_checksum.h>
	#endif

	#include "br_private.h"

	void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
	{
	struct net_bridge_port *p;
	bool neigh_suppress = false;

	list_for_each_entry(p, &br->port_list, list) {
	if (p->flags & BR_NEIGH_SUPPRESS) {
	neigh_suppress = true;
	break;
	}
	}

	br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress);
	}

	#if IS_ENABLED(CONFIG_INET)
	static void br_arp_send(struct net_bridge br, struct net_bridge_port p,
	struct net_device *dev, __be32 dest_ip, __be32 src_ip,
	const unsigned char *dest_hw,
	const unsigned char *src_hw,
	const unsigned char *target_hw,
	__be16 vlan_proto, u16 vlan_tci)
	{
	struct net_bridge_vlan_group *vg;
	struct sk_buff *skb;
	u16 pvid;

	netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n",
	dev->name, &dest_ip, dest_hw, &src_ip, src_hw);

	if (!vlan_tci) {
	arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
	dest_hw, src_hw, target_hw);
	return;
	}

	skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
	dest_hw, src_hw, target_hw);
	if (!skb)
	return;

	if (p)
	vg = nbp_vlan_group_rcu(p);
	else
	vg = br_vlan_group_rcu(br);
	pvid = br_get_pvid(vg);
	if (pvid == (vlan_tci & VLAN_VID_MASK))
	vlan_tci = 0;

	if (vlan_tci)
	__vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);

	if (p) {
	arp_xmit(skb);
	} else {
	skb_reset_mac_header(skb);
	__skb_pull(skb, skb_network_offset(skb));
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	skb->pkt_type = PACKET_HOST;

	netif_rx_ni(skb);
	}
	}

	static int br_chk_addr_ip(struct net_device dev, void data)
	{
	__be32 ip = (__be32 )data;
	struct in_device *in_dev;
	__be32 addr = 0;

	in_dev = __in_dev_get_rcu(dev);
	if (in_dev)
	addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip,
	RT_SCOPE_HOST);

	if (addr == ip)
	return 1;

	return 0;
	}

	static bool br_is_local_ip(struct net_device *dev, __be32 ip)
	{
	if (br_chk_addr_ip(dev, &ip))
	return true;

	/* check if ip is configured on upper dev */
	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &ip))
	return true;

	return false;
	}

	void br_do_proxy_suppress_arp(struct sk_buff skb, struct net_bridge br,
	u16 vid, struct net_bridge_port *p)
	{
	struct net_device *dev = br->dev;
	struct net_device *vlandev = dev;
	struct neighbour *n;
	struct arphdr *parp;
	u8 arpptr, sha;
	__be32 sip, tip;

	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;

	if ((dev->flags & IFF_NOARP) \|\|
	!pskb_may_pull(skb, arp_hdr_len(dev)))
	return;

	parp = arp_hdr(skb);

	if (parp->ar_pro != htons(ETH_P_IP) \|\|
	parp->ar_hln != dev->addr_len \|\|
	parp->ar_pln != 4)
	return;

	arpptr = (u8 *)parp + sizeof(struct arphdr);
	sha = arpptr;
	arpptr += dev->addr_len; /* sha */
	memcpy(&sip, arpptr, sizeof(sip));
	arpptr += sizeof(sip);
	arpptr += dev->addr_len; /* tha */
	memcpy(&tip, arpptr, sizeof(tip));

	if (ipv4_is_loopback(tip) \|\|
	ipv4_is_multicast(tip))
	return;

	if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
	if (p && (p->flags & BR_NEIGH_SUPPRESS))
	return;
	if (parp->ar_op != htons(ARPOP_RREQUEST) &&
	parp->ar_op != htons(ARPOP_RREPLY) &&
	(ipv4_is_zeronet(sip) \|\| sip == tip)) {
	/* prevent flooding to neigh suppress ports */
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	return;
	}
	}

	if (parp->ar_op != htons(ARPOP_REQUEST))
	return;

	if (vid != 0) {
	vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
	vid);
	if (!vlandev)
	return;
	}

	if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
	br_is_local_ip(vlandev, tip)) {
	/* its our local ip, so don't proxy reply
	* and don't forward to neigh suppress ports
	*/
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	return;
	}

	n = neigh_lookup(&arp_tbl, &tip, vlandev);
	if (n) {
	struct net_bridge_fdb_entry *f;

	if (!(n->nud_state & NUD_VALID)) {
	neigh_release(n);
	return;
	}

	f = br_fdb_find_rcu(br, n->ha, vid);
	if (f) {
	bool replied = false;

	if ((p && (p->flags & BR_PROXYARP)) \|\|
	(f->dst && (f->dst->flags & (BR_PROXYARP_WIFI \|
	BR_NEIGH_SUPPRESS)))) {
	if (!vid)
	br_arp_send(br, p, skb->dev, sip, tip,
	sha, n->ha, sha, 0, 0);
	else
	br_arp_send(br, p, skb->dev, sip, tip,
	sha, n->ha, sha,
	skb->vlan_proto,
	skb_vlan_tag_get(skb));
	replied = true;
	}

	/* If we have replied or as long as we know the
	* mac, indicate to arp replied
	*/
	if (replied \|\|
	br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	}

	neigh_release(n);
	}
	}
	#endif

	#if IS_ENABLED(CONFIG_IPV6)
	struct nd_msg br_is_nd_neigh_msg(struct sk_buff skb, struct nd_msg *msg)
	{
	struct nd_msg *m;

	m = skb_header_pointer(skb, skb_network_offset(skb) +
	sizeof(struct ipv6hdr), sizeof(*msg), msg);
	if (!m)
	return NULL;

	if (m->icmph.icmp6_code != 0 \|\|
	(m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION &&
	m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT))
	return NULL;

	return m;
	}

	static void br_nd_send(struct net_bridge br, struct net_bridge_port p,
	struct sk_buff request, struct neighbour n,
	__be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns)
	{
	struct net_device *dev = request->dev;
	struct net_bridge_vlan_group *vg;
	struct sk_buff *reply;
	struct nd_msg *na;
	struct ipv6hdr *pip6;
	int na_olen = 8; /* opt hdr + ETH_ALEN for target */
	int ns_olen;
	int i, len;
	u8 *daddr;
	u16 pvid;

	if (!dev)
	return;

	len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
	sizeof(*na) + na_olen + dev->needed_tailroom;

	reply = alloc_skb(len, GFP_ATOMIC);
	if (!reply)
	return;

	reply->protocol = htons(ETH_P_IPV6);
	reply->dev = dev;
	skb_reserve(reply, LL_RESERVED_SPACE(dev));
	skb_push(reply, sizeof(struct ethhdr));
	skb_set_mac_header(reply, 0);

	daddr = eth_hdr(request)->h_source;

	/* Do we need option processing ? */
	ns_olen = request->len - (skb_network_offset(request) +
	sizeof(struct ipv6hdr)) - sizeof(*ns);
	for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) {
	if (!ns->opt[i + 1]) {
	kfree_skb(reply);
	return;
	}
	if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
	daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
	break;
	}
	}

	/* Ethernet header */
	ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
	ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
	eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
	reply->protocol = htons(ETH_P_IPV6);

	skb_pull(reply, sizeof(struct ethhdr));
	skb_set_network_header(reply, 0);
	skb_put(reply, sizeof(struct ipv6hdr));

	/* IPv6 header */
	pip6 = ipv6_hdr(reply);
	memset(pip6, 0, sizeof(struct ipv6hdr));
	pip6->version = 6;
	pip6->priority = ipv6_hdr(request)->priority;
	pip6->nexthdr = IPPROTO_ICMPV6;
	pip6->hop_limit = 255;
	pip6->daddr = ipv6_hdr(request)->saddr;
	pip6->saddr = (struct in6_addr )n->primary_key;

	skb_pull(reply, sizeof(struct ipv6hdr));
	skb_set_transport_header(reply, 0);

	na = (struct nd_msg )skb_put(reply, sizeof(na) + na_olen);

	/* Neighbor Advertisement */
	memset(na, 0, sizeof(*na) + na_olen);
	na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
	na->icmph.icmp6_router = (n->flags & NTF_ROUTER) ? 1 : 0;
	na->icmph.icmp6_override = 1;
	na->icmph.icmp6_solicited = 1;
	na->target = ns->target;
	ether_addr_copy(&na->opt[2], n->ha);
	na->opt[0] = ND_OPT_TARGET_LL_ADDR;
	na->opt[1] = na_olen >> 3;

	na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
	&pip6->daddr,
	sizeof(*na) + na_olen,
	IPPROTO_ICMPV6,
	csum_partial(na, sizeof(*na) + na_olen, 0));

	pip6->payload_len = htons(sizeof(*na) + na_olen);

	skb_push(reply, sizeof(struct ipv6hdr));
	skb_push(reply, sizeof(struct ethhdr));

	reply->ip_summed = CHECKSUM_UNNECESSARY;

	if (p)
	vg = nbp_vlan_group_rcu(p);
	else
	vg = br_vlan_group_rcu(br);
	pvid = br_get_pvid(vg);
	if (pvid == (vlan_tci & VLAN_VID_MASK))
	vlan_tci = 0;

	if (vlan_tci)
	__vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci);

	netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n",
	dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha);

	if (p) {
	dev_queue_xmit(reply);
	} else {
	skb_reset_mac_header(reply);
	__skb_pull(reply, skb_network_offset(reply));
	reply->ip_summed = CHECKSUM_UNNECESSARY;
	reply->pkt_type = PACKET_HOST;

	netif_rx_ni(reply);
	}
	}

	static int br_chk_addr_ip6(struct net_device dev, void data)
	{
	struct in6_addr addr = (struct in6_addr )data;

	if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
	return 1;

	return 0;
	}

	static bool br_is_local_ip6(struct net_device dev, struct in6_addr addr)

	{
	if (br_chk_addr_ip6(dev, addr))
	return true;

	/* check if ip is configured on upper dev */
	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, addr))
	return true;

	return false;
	}

	void br_do_suppress_nd(struct sk_buff skb, struct net_bridge br,
	u16 vid, struct net_bridge_port p, struct nd_msg msg)
	{
	struct net_device *dev = br->dev;
	struct net_device *vlandev = NULL;
	struct in6_addr saddr, daddr;
	struct ipv6hdr *iphdr;
	struct neighbour *n;

	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;

	if (p && (p->flags & BR_NEIGH_SUPPRESS))
	return;

	if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
	!msg->icmph.icmp6_solicited) {
	/* prevent flooding to neigh suppress ports */
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	return;
	}

	if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
	return;

	iphdr = ipv6_hdr(skb);
	saddr = &iphdr->saddr;
	daddr = &iphdr->daddr;

	if (ipv6_addr_any(saddr) \|\| !ipv6_addr_cmp(saddr, daddr)) {
	/* prevent flooding to neigh suppress ports */
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	return;
	}

	if (vid != 0) {
	/* build neigh table lookup on the vlan device */
	vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
	vid);
	if (!vlandev)
	return;
	} else {
	vlandev = dev;
	}

	if (br_is_local_ip6(vlandev, &msg->target)) {
	/* its our own ip, so don't proxy reply
	* and don't forward to arp suppress ports
	*/
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	return;
	}

	n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
	if (n) {
	struct net_bridge_fdb_entry *f;

	if (!(n->nud_state & NUD_VALID)) {
	neigh_release(n);
	return;
	}

	f = br_fdb_find_rcu(br, n->ha, vid);
	if (f) {
	bool replied = false;

	if (f->dst && (f->dst->flags & BR_NEIGH_SUPPRESS)) {
	if (vid != 0)
	br_nd_send(br, p, skb, n,
	skb->vlan_proto,
	skb_vlan_tag_get(skb), msg);
	else
	br_nd_send(br, p, skb, n, 0, 0, msg);
	replied = true;
	}

	/* If we have replied or as long as we know the
	* mac, indicate to NEIGH_SUPPRESS ports that we
	* have replied
	*/
	if (replied \|\|
	br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
	BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
	}
	neigh_release(n);
	}
	}
	#endif