Merge branch 'bridge-neigh-msg-proxy-and-flood-suppression-support'

Roopa Prabhu says:

====================
bridge: neigh msg proxy and flood suppression support

This series implements arp and nd suppression in the bridge
driver for ethernet vpns. It implements rfc7432, section 10
https://tools.ietf.org/html/rfc7432#section-10
for ethernet VPN deployments. It is similar to the existing
BR_PROXYARP* flags but has a few semantic differences to conform
to EVPN standard. Unlike the existing flags, this new flag suppresses
flood of all neigh discovery packets (arp and nd) to tunnel ports.
Supports both vlan filtering and non-vlan filtering bridges.

In case of EVPN, it is mainly used to avoid flooding
of arp and nd packets to tunnel ports like vxlan.

v2 : rebase to latest + address some optimization feedback from Nikolay.
v3 : fix kbuild reported build errors with CONFIG_INET off
v4 : simplify port flag mask as suggested by stephen
v5 : address some feedback from Toshiaki
v6 : some v5 cleanups in nd suppress (keep it consistent with arp suppress)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_bridge.h

@@ -49,6 +49,7 @@ struct br_ip_list {
 #define BR_MULTICAST_TO_UNICAST	BIT(12)
 #define BR_VLAN_TUNNEL		BIT(13)
 #define BR_BCAST_FLOOD		BIT(14)
+#define BR_NEIGH_SUPPRESS	BIT(15)
 
 #define BR_DEFAULT_AGEING_TIME	(300 * HZ)
 

include/uapi/linux/if_link.h

@@ -327,6 +327,7 @@ enum {
 	IFLA_BRPORT_VLAN_TUNNEL,
 	IFLA_BRPORT_BCAST_FLOOD,
 	IFLA_BRPORT_GROUP_FWD_MASK,
+	IFLA_BRPORT_NEIGH_SUPPRESS,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

net/bridge/Makefile

@@ -7,7 +7,7 @@ obj-$(CONFIG_BRIDGE) += bridge.o
 bridge-y	:= br.o br_device.o br_fdb.o br_forward.o br_if.o br_input.o \
 			br_ioctl.o br_stp.o br_stp_bpdu.o \
 			br_stp_if.o br_stp_timer.o br_netlink.o \
-			br_netlink_tunnel.o
+			br_netlink_tunnel.o br_arp_nd_proxy.o
 
 bridge-$(CONFIG_SYSFS) += br_sysfs_if.o br_sysfs_br.o
 

net/bridge/br_device.c

@@ -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 +58,30 @@ 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);
+	} 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;
 	if (is_broadcast_ether_addr(dest)) {
 		br_flood(br, skb, BR_PKT_BROADCAST, false, true);

net/bridge/br_forward.c

@@ -204,7 +204,7 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		/* Do not flood to ports that enable proxy ARP */
 		if (p->flags & BR_PROXYARP)
 			continue;
-		if ((p->flags & BR_PROXYARP_WIFI) &&
+		if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
 		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
 			continue;
 

net/bridge/br_if.c

@@ -310,6 +310,8 @@ void br_dev_delete(struct net_device *dev, struct list_head *head)
 		del_nbp(p);
 	}
 
+	br_recalculate_neigh_suppress_enabled(br);
+
 	br_fdb_delete_by_port(br, NULL, 0, 1);
 
 	cancel_delayed_work_sync(&br->gc_work);
@@ -660,4 +662,7 @@ void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
 
 	if (mask & BR_AUTO_MASK)
 		nbp_update_port_count(br);
+
+	if (mask & BR_NEIGH_SUPPRESS)
+		br_recalculate_neigh_suppress_enabled(br);
 }

net/bridge/br_input.c

@@ -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 +115,22 @@ 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);
+	} 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) {
 	case BR_PKT_MULTICAST:

net/bridge/br_netlink.c

@@ -138,6 +138,7 @@ static inline size_t br_port_info_size(void)
 		+ nla_total_size(1)	/* IFLA_BRPORT_PROXYARP */
 		+ nla_total_size(1)	/* IFLA_BRPORT_PROXYARP_WIFI */
 		+ nla_total_size(1)	/* IFLA_BRPORT_VLAN_TUNNEL */
+		+ nla_total_size(1)	/* IFLA_BRPORT_NEIGH_SUPPRESS */
 		+ nla_total_size(sizeof(struct ifla_bridge_id))	/* IFLA_BRPORT_ROOT_ID */
 		+ nla_total_size(sizeof(struct ifla_bridge_id))	/* IFLA_BRPORT_BRIDGE_ID */
 		+ nla_total_size(sizeof(u16))	/* IFLA_BRPORT_DESIGNATED_PORT */
@@ -210,7 +211,9 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put_u8(skb, IFLA_BRPORT_CONFIG_PENDING, p->config_pending) ||
 	    nla_put_u8(skb, IFLA_BRPORT_VLAN_TUNNEL, !!(p->flags &
 							BR_VLAN_TUNNEL)) ||
-	    nla_put_u16(skb, IFLA_BRPORT_GROUP_FWD_MASK, p->group_fwd_mask))
+	    nla_put_u16(skb, IFLA_BRPORT_GROUP_FWD_MASK, p->group_fwd_mask) ||
+	    nla_put_u8(skb, IFLA_BRPORT_NEIGH_SUPPRESS,
+		       !!(p->flags & BR_NEIGH_SUPPRESS)))
 		return -EMSGSIZE;
 
 	timerval = br_timer_value(&p->message_age_timer);
@@ -785,6 +788,11 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
 		p->group_fwd_mask = fwd_mask;
 	}
 
+	err = br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_SUPPRESS,
+			       BR_NEIGH_SUPPRESS);
+	if (err)
+		return err;
+
 	br_port_flags_change(p, old_flags ^ p->flags);
 	return 0;
 }

net/bridge/br_private.h

@@ -404,6 +404,7 @@ struct net_bridge {
 #ifdef CONFIG_NET_SWITCHDEV
 	int offload_fwd_mark;
 #endif
+	bool				neigh_suppress_enabled;
 };
 
 struct br_input_skb_cb {
@@ -1139,4 +1140,11 @@ 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);
+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

net/bridge/br_sysfs_if.c

@@ -191,6 +191,7 @@ BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
 BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
 BRPORT_ATTR_FLAG(multicast_flood, BR_MCAST_FLOOD);
 BRPORT_ATTR_FLAG(broadcast_flood, BR_BCAST_FLOOD);
+BRPORT_ATTR_FLAG(neigh_suppress, BR_NEIGH_SUPPRESS);
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@@ -241,6 +242,7 @@ static const struct brport_attribute *brport_attrs[] = {
 	&brport_attr_multicast_flood,
 	&brport_attr_broadcast_flood,
 	&brport_attr_group_fwd_mask,
+	&brport_attr_neigh_suppress,
 	NULL
 };