Commit 057658cb authored by Roopa Prabhu's avatar Roopa Prabhu Committed by David S. Miller
Browse files

bridge: suppress arp pkts on BR_NEIGH_SUPPRESS ports 



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

Moves existing br_do_proxy_arp to br_do_proxy_suppress_arp
to support both proxy arp and neigh suppress.

Signed-off-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 821f1b21

net/bridge/br_arp_nd_proxy.c

+188 −0
Original line number Diff line number Diff line
@@ -14,6 +14,14 @@ 
 */



#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 "br_private.h"



void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
@@ -30,3 +38,183 @@ void br_recalculate_neigh_suppress_enabled(struct net_bridge *br) 


	br->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 = false;



	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->neigh_suppress_enabled) {

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

			return;

		if (ipv4_is_zeronet(sip) || sip == tip) {

			/* prevent flooding to neigh suppress ports */

			BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;

			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->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 = true;

		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->neigh_suppress_enabled)

				BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;

		}



		neigh_release(n);

	}

}

#endif

net/bridge/br_device.c

+9 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);

	const struct nf_br_ops *nf_ops;

	const unsigned char *dest;

	struct ethhdr *eth;

	u16 vid = 0;



	rcu_read_lock();
@@ -57,11 +58,19 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) 
	BR_INPUT_SKB_CB(skb)->brdev = dev;



	skb_reset_mac_header(skb);

	eth = eth_hdr(skb);

	skb_pull(skb, ETH_HLEN);



	if (!br_allowed_ingress(br, br_vlan_group_rcu(br), skb, &vid))

		goto out;



	if (IS_ENABLED(CONFIG_INET) &&

	    (eth->h_proto == htons(ETH_P_ARP) ||

	     eth->h_proto == htons(ETH_P_RARP)) &&

	    br->neigh_suppress_enabled) {

		br_do_proxy_suppress_arp(skb, br, vid, NULL);

	}



	dest = eth_hdr(skb)->h_dest;

	if (is_broadcast_ether_addr(dest)) {

		br_flood(br, skb, BR_PKT_BROADCAST, false, true);

net/bridge/br_input.c

+5 −58
Original line number Diff line number Diff line
@@ -71,62 +71,6 @@ static int br_pass_frame_up(struct sk_buff *skb) 
		       br_netif_receive_skb);

}



static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,

			    u16 vid, struct net_bridge_port *p)

{

	struct net_device *dev = br->dev;

	struct neighbour *n;

	struct arphdr *parp;

	u8 *arpptr, *sha;

	__be32 sip, tip;



	BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;



	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_op != htons(ARPOP_REQUEST) ||

	    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;



	n = neigh_lookup(&arp_tbl, &tip, dev);

	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 && ((p->flags & BR_PROXYARP) ||

			  (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {

			arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,

				 sha, n->ha, sha);

			BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;

		}



		neigh_release(n);

	}

}



/* note: already called with rcu_read_lock */

int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)

{
@@ -171,8 +115,11 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb 


	BR_INPUT_SKB_CB(skb)->brdev = br->dev;



	if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))

		br_do_proxy_arp(skb, br, vid, p);

	if (IS_ENABLED(CONFIG_INET) &&

	    (skb->protocol == htons(ETH_P_ARP) ||

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

		br_do_proxy_suppress_arp(skb, br, vid, p);

	}



	switch (pkt_type) {

	case BR_PKT_MULTICAST:

net/bridge/br_private.h

+3 −0
Original line number Diff line number Diff line
@@ -1140,5 +1140,8 @@ static inline void br_switchdev_frame_unmark(struct sk_buff *skb) 
}

#endif /* CONFIG_NET_SWITCHDEV */



/* br_arp_nd_proxy.c */

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);

#endif

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