Commit ed842fae authored by Roopa Prabhu's avatar Roopa Prabhu Committed by David S. Miller
Browse files

bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports 



This patch avoids flooding and proxies ndisc packets
for BR_NEIGH_SUPPRESS ports.

Signed-off-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 057658cb

net/bridge/br_arp_nd_proxy.c

+249 −0
Original line number Diff line number Diff line
@@ -21,6 +21,9 @@ 
#include <linux/if_vlan.h>

#include <linux/inetdevice.h>

#include <net/addrconf.h>

#if IS_ENABLED(CONFIG_IPV6)

#include <net/ip6_checksum.h>

#endif



#include "br_private.h"
@@ -218,3 +221,249 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br, 
	}

}

#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] == 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 = 0; /* XXX: should be 1 ? */

	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 = false;



	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 = true;

		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 = true;

		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 = true;

		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->neigh_suppress_enabled)

				BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;

		}

		neigh_release(n);

	}

}

#endif

net/bridge/br_device.c

+11 −0
Original line number Diff line number Diff line
@@ -69,6 +69,17 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) 
	     eth->h_proto == htons(ETH_P_RARP)) &&

	    br->neigh_suppress_enabled) {

		br_do_proxy_suppress_arp(skb, br, vid, NULL);

	} else if (IS_ENABLED(CONFIG_IPV6) &&

		   skb->protocol == htons(ETH_P_IPV6) &&

		   br->neigh_suppress_enabled &&

		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +

				 sizeof(struct nd_msg)) &&

		   ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {

			struct nd_msg *msg, _msg;



			msg = br_is_nd_neigh_msg(skb, &_msg);

			if (msg)

				br_do_suppress_nd(skb, br, vid, NULL, msg);

	}



	dest = eth_hdr(skb)->h_dest;

net/bridge/br_input.c

+11 −0
Original line number Diff line number Diff line
@@ -119,6 +119,17 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb 
	    (skb->protocol == htons(ETH_P_ARP) ||

	     skb->protocol == htons(ETH_P_RARP))) {

		br_do_proxy_suppress_arp(skb, br, vid, p);

	} else if (IS_ENABLED(CONFIG_IPV6) &&

		   skb->protocol == htons(ETH_P_IPV6) &&

		   br->neigh_suppress_enabled &&

		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +

				 sizeof(struct nd_msg)) &&

		   ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {

			struct nd_msg *msg, _msg;



			msg = br_is_nd_neigh_msg(skb, &_msg);

			if (msg)

				br_do_suppress_nd(skb, br, vid, p, msg);

	}



	switch (pkt_type) {

net/bridge/br_private.h

+3 −0
Original line number Diff line number Diff line
@@ -1144,4 +1144,7 @@ static inline void br_switchdev_frame_unmark(struct sk_buff *skb) 
void br_recalculate_neigh_suppress_enabled(struct net_bridge *br);

void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,

			      u16 vid, struct net_bridge_port *p);

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 nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *m);

#endif