udp_tunnel: Seperate ipv6 functions into its own file.

Add ip6_udp_tunnel.c for ipv6 UDP tunnel functions to avoid ifdefs
in udp_tunnel.c

Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
new file mode 100644
index 0000000..bcfbb4b
--- /dev/null
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -0,0 +1,63 @@
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/udp.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/in6.h>
+#include <net/udp.h>
+#include <net/udp_tunnel.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/ip6_tunnel.h>
+#include <net/ip6_checksum.h>
+
+int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
+		     struct socket **sockp)
+{
+	struct sockaddr_in6 udp6_addr;
+	int err;
+	struct socket *sock = NULL;
+
+	err = sock_create_kern(AF_INET6, SOCK_DGRAM, 0, &sock);
+	if (err < 0)
+		goto error;
+
+	sk_change_net(sock->sk, net);
+
+	udp6_addr.sin6_family = AF_INET6;
+	memcpy(&udp6_addr.sin6_addr, &cfg->local_ip6,
+	       sizeof(udp6_addr.sin6_addr));
+	udp6_addr.sin6_port = cfg->local_udp_port;
+	err = kernel_bind(sock, (struct sockaddr *)&udp6_addr,
+			  sizeof(udp6_addr));
+	if (err < 0)
+		goto error;
+
+	if (cfg->peer_udp_port) {
+		udp6_addr.sin6_family = AF_INET6;
+		memcpy(&udp6_addr.sin6_addr, &cfg->peer_ip6,
+		       sizeof(udp6_addr.sin6_addr));
+		udp6_addr.sin6_port = cfg->peer_udp_port;
+		err = kernel_connect(sock,
+				     (struct sockaddr *)&udp6_addr,
+				     sizeof(udp6_addr), 0);
+	}
+	if (err < 0)
+		goto error;
+
+	udp_set_no_check6_tx(sock->sk, !cfg->use_udp6_tx_checksums);
+	udp_set_no_check6_rx(sock->sk, !cfg->use_udp6_rx_checksums);
+
+	*sockp = sock;
+	return 0;
+
+error:
+	if (sock) {
+		kernel_sock_shutdown(sock, SHUT_RDWR);
+		sk_release_kernel(sock->sk);
+	}
+	*sockp = NULL;
+	return err;
+}
+EXPORT_SYMBOL_GPL(udp_sock_create6);