1 files changed, 485 insertions, 0 deletions

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
new file mode 100644
index 000000000..b45c00c01
--- /dev/null
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -0,0 +1,485 @@
+// 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(skb);
+	}
+}
+
+static int br_chk_addr_ip(struct net_device *dev,
+			  struct netdev_nested_priv *priv)
+{
+	__be32 ip = *(__be32 *)priv->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)
+{
+	struct netdev_nested_priv priv = {
+		.data = (void *)&ip,
+	};
+
+	if (br_chk_addr_ip(dev, &priv))
+		return true;
+
+	/* check if ip is configured on upper dev */
+	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &priv))
+		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 (!(READ_ONCE(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(reply);
+	}
+}
+
+static int br_chk_addr_ip6(struct net_device *dev,
+			   struct netdev_nested_priv *priv)
+{
+	struct in6_addr *addr = (struct in6_addr *)priv->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)
+
+{
+	struct netdev_nested_priv priv = {
+		.data = (void *)addr,
+	};
+
+	if (br_chk_addr_ip6(dev, &priv))
+		return true;
+
+	/* check if ip is configured on upper dev */
+	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, &priv))
+		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 (!(READ_ONCE(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