geneve: Add geneve_get_rx_port support

BugLink: http://bugs.launchpad.net/bugs/1536474

This patch adds an op that the drivers can call into to get existing
geneve ports.
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 05ca4029)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/net/geneve.c

@@ -1109,6 +1109,30 @@ static struct device_type geneve_type = {
 	.name = "geneve",
 };
 
+/* Calls the ndo_add_geneve_port of the caller in order to
+ * supply the listening GENEVE udp ports. Callers are expected
+ * to implement the ndo_add_geneve_port.
+ */
+void geneve_get_rx_port(struct net_device *dev)
+{
+	struct net *net = dev_net(dev);
+	struct geneve_net *gn = net_generic(net, geneve_net_id);
+	struct geneve_sock *gs;
+	sa_family_t sa_family;
+	struct sock *sk;
+	__be16 port;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(gs, &gn->sock_list, list) {
+		sk = gs->sock->sk;
+		sa_family = sk->sk_family;
+		port = inet_sk(sk)->inet_sport;
+		dev->netdev_ops->ndo_add_geneve_port(dev, sa_family, port);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(geneve_get_rx_port);
+
 /* Initialize the device structure. */
 static void geneve_setup(struct net_device *dev)
 {

include/net/geneve.h

@@ -62,6 +62,14 @@ struct genevehdr {
 	struct geneve_opt options[];
 };
 
+#if IS_ENABLED(CONFIG_GENEVE)
+void geneve_get_rx_port(struct net_device *netdev);
+#else
+static inline void geneve_get_rx_port(struct net_device *netdev)
+{
+}
+#endif
+
 #ifdef CONFIG_INET
 struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
 					u8 name_assign_type, u16 dst_port);