[PATCH net-next v2 1/2] net: vxlan: enable local address bind for vxlan sockets

[Richard Gobert]

This patch adds support for binding to a local address in vxlan sockets.
It achieves this by using vxlan_addr union to represent a local address
to bind to, and copying it to udp_port_cfg in vxlan_create_sock.

Also change vxlan_find_sock to search the socket based on the listening address.

Signed-off-by: Richard Gobert <richardbgobert@xxxxxxxxx>
---
 drivers/net/vxlan/vxlan_core.c | 53 ++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index ba59e92ab941..9a797147beb7 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -72,22 +72,34 @@ static inline bool vxlan_collect_metadata(struct vxlan_sock *vs)
 }
 
 /* Find VXLAN socket based on network namespace, address family, UDP port,
- * enabled unshareable flags and socket device binding (see l3mdev with
- * non-default VRF).
+ * bounded address, enabled unshareable flags and socket device binding
+ * (see l3mdev with non-default VRF).
  */
 static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
-					  __be16 port, u32 flags, int ifindex)
+					  __be16 port, u32 flags, int ifindex, union vxlan_addr *saddr)
 {
 	struct vxlan_sock *vs;
 
 	flags &= VXLAN_F_RCV_FLAGS;
 
 	hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
-		if (inet_sk(vs->sock->sk)->inet_sport == port &&
+		struct sock *sk = vs->sock->sk;
+		struct inet_sock *inet = inet_sk(sk);
+
+		if (inet->inet_sport == port &&
 		    vxlan_get_sk_family(vs) == family &&
 		    vs->flags == flags &&
-		    vs->sock->sk->sk_bound_dev_if == ifindex)
-			return vs;
+		    vs->sock->sk->sk_bound_dev_if == ifindex) {
+			if (family == AF_INET && inet->inet_rcv_saddr == saddr->sin.sin_addr.s_addr) {
+				return vs;
+			}
+#if IS_ENABLED(CONFIG_IPV6)
+			else if (ipv6_addr_cmp(&sk->sk_v6_rcv_saddr, &saddr->sin6.sin6_addr) == 0)
+				return vs;
+			}
+#endif
+		}
+
 	}
 	return NULL;
 }
@@ -135,11 +147,11 @@ static struct vxlan_dev *vxlan_vs_find_vni(struct vxlan_sock *vs,
 /* Look up VNI in a per net namespace table */
 static struct vxlan_dev *vxlan_find_vni(struct net *net, int ifindex,
 					__be32 vni, sa_family_t family,
-					__be16 port, u32 flags)
+					__be16 port, u32 flags, union vxlan_addr *saddr)
 {
 	struct vxlan_sock *vs;
 
-	vs = vxlan_find_sock(net, family, port, flags, ifindex);
+	vs = vxlan_find_sock(net, family, port, flags, ifindex, saddr);
 	if (!vs)
 		return NULL;
 
@@ -2315,7 +2327,7 @@ static int encap_bypass_if_local(struct sk_buff *skb, struct net_device *dev,
 		dst_release(dst);
 		dst_vxlan = vxlan_find_vni(vxlan->net, dst_ifindex, vni,
 					   addr_family, dst_port,
-					   vxlan->cfg.flags);
+					   vxlan->cfg.flags, &vxlan->cfg.saddr);
 		if (!dst_vxlan) {
 			DEV_STATS_INC(dev, tx_errors);
 			vxlan_vnifilter_count(vxlan, vni, NULL,
@@ -3503,8 +3515,9 @@ static const struct ethtool_ops vxlan_ethtool_ops = {
 	.get_link_ksettings	= vxlan_get_link_ksettings,
 };
 
-static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
-					__be16 port, u32 flags, int ifindex)
+static struct socket *vxlan_create_sock(struct net *net, bool ipv6, __be16 port,
+					u32 flags, int ifindex,
+					union vxlan_addr *addr)
 {
 	struct socket *sock;
 	struct udp_port_cfg udp_conf;
@@ -3517,8 +3530,17 @@ static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
 		udp_conf.use_udp6_rx_checksums =
 		    !(flags & VXLAN_F_UDP_ZERO_CSUM6_RX);
 		udp_conf.ipv6_v6only = 1;
+#if IS_ENABLED(CONFIG_IPV6)
+		memcpy(&udp_conf.local_ip6.s6_addr32,
+		       &addr->sin6.sin6_addr.s6_addr32,
+		       sizeof(addr->sin6.sin6_addr.s6_addr32));
+#endif
 	} else {
 		udp_conf.family = AF_INET;
+		udp_conf.local_ip.s_addr = addr->sin.sin_addr.s_addr;
+		memcpy(&udp_conf.local_ip.s_addr,
+		       &addr->sin.sin_addr.s_addr,
+		       sizeof(addr->sin.sin_addr.s_addr));
 	}
 
 	udp_conf.local_udp_port = port;
@@ -3536,7 +3558,8 @@ static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
 /* Create new listen socket if needed */
 static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
 					      __be16 port, u32 flags,
-					      int ifindex)
+					      int ifindex,
+					      union vxlan_addr *addr)
 {
 	struct vxlan_net *vn = net_generic(net, vxlan_net_id);
 	struct vxlan_sock *vs;
@@ -3551,7 +3574,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
 	for (h = 0; h < VNI_HASH_SIZE; ++h)
 		INIT_HLIST_HEAD(&vs->vni_list[h]);
 
-	sock = vxlan_create_sock(net, ipv6, port, flags, ifindex);
+	sock = vxlan_create_sock(net, ipv6, port, flags, ifindex, addr);
 	if (IS_ERR(sock)) {
 		kfree(vs);
 		return ERR_CAST(sock);
@@ -3605,7 +3628,7 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
 		spin_lock(&vn->sock_lock);
 		vs = vxlan_find_sock(vxlan->net, ipv6 ? AF_INET6 : AF_INET,
 				     vxlan->cfg.dst_port, vxlan->cfg.flags,
-				     l3mdev_index);
+				     l3mdev_index, &vxlan->cfg.saddr);
 		if (vs && !refcount_inc_not_zero(&vs->refcnt)) {
 			spin_unlock(&vn->sock_lock);
 			return -EBUSY;
@@ -3615,7 +3638,7 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
 	if (!vs)
 		vs = vxlan_socket_create(vxlan->net, ipv6,
 					 vxlan->cfg.dst_port, vxlan->cfg.flags,
-					 l3mdev_index);
+					 l3mdev_index, &vxlan->cfg.saddr);
 	if (IS_ERR(vs))
 		return PTR_ERR(vs);
 #if IS_ENABLED(CONFIG_IPV6)
-- 
2.36.1