v4.19.13 snapshot.
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
new file mode 100644
index 0000000..6539ff1
--- /dev/null
+++ b/net/ipv4/udp_tunnel.c
@@ -0,0 +1,216 @@
+#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 <net/dst_metadata.h>
+#include <net/net_namespace.h>
+#include <net/udp.h>
+#include <net/udp_tunnel.h>
+
+int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
+ struct socket **sockp)
+{
+ int err;
+ struct socket *sock = NULL;
+ struct sockaddr_in udp_addr;
+
+ err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 0, &sock);
+ if (err < 0)
+ goto error;
+
+ udp_addr.sin_family = AF_INET;
+ udp_addr.sin_addr = cfg->local_ip;
+ udp_addr.sin_port = cfg->local_udp_port;
+ err = kernel_bind(sock, (struct sockaddr *)&udp_addr,
+ sizeof(udp_addr));
+ if (err < 0)
+ goto error;
+
+ if (cfg->peer_udp_port) {
+ udp_addr.sin_family = AF_INET;
+ udp_addr.sin_addr = cfg->peer_ip;
+ udp_addr.sin_port = cfg->peer_udp_port;
+ err = kernel_connect(sock, (struct sockaddr *)&udp_addr,
+ sizeof(udp_addr), 0);
+ if (err < 0)
+ goto error;
+ }
+
+ sock->sk->sk_no_check_tx = !cfg->use_udp_checksums;
+
+ *sockp = sock;
+ return 0;
+
+error:
+ if (sock) {
+ kernel_sock_shutdown(sock, SHUT_RDWR);
+ sock_release(sock);
+ }
+ *sockp = NULL;
+ return err;
+}
+EXPORT_SYMBOL(udp_sock_create4);
+
+void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
+ struct udp_tunnel_sock_cfg *cfg)
+{
+ struct sock *sk = sock->sk;
+
+ /* Disable multicast loopback */
+ inet_sk(sk)->mc_loop = 0;
+
+ /* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
+ inet_inc_convert_csum(sk);
+
+ rcu_assign_sk_user_data(sk, cfg->sk_user_data);
+
+ udp_sk(sk)->encap_type = cfg->encap_type;
+ udp_sk(sk)->encap_rcv = cfg->encap_rcv;
+ udp_sk(sk)->encap_destroy = cfg->encap_destroy;
+ udp_sk(sk)->gro_receive = cfg->gro_receive;
+ udp_sk(sk)->gro_complete = cfg->gro_complete;
+
+ udp_tunnel_encap_enable(sock);
+}
+EXPORT_SYMBOL_GPL(setup_udp_tunnel_sock);
+
+void udp_tunnel_push_rx_port(struct net_device *dev, struct socket *sock,
+ unsigned short type)
+{
+ struct sock *sk = sock->sk;
+ struct udp_tunnel_info ti;
+
+ if (!dev->netdev_ops->ndo_udp_tunnel_add ||
+ !(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+ return;
+
+ ti.type = type;
+ ti.sa_family = sk->sk_family;
+ ti.port = inet_sk(sk)->inet_sport;
+
+ dev->netdev_ops->ndo_udp_tunnel_add(dev, &ti);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_push_rx_port);
+
+void udp_tunnel_drop_rx_port(struct net_device *dev, struct socket *sock,
+ unsigned short type)
+{
+ struct sock *sk = sock->sk;
+ struct udp_tunnel_info ti;
+
+ if (!dev->netdev_ops->ndo_udp_tunnel_del ||
+ !(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+ return;
+
+ ti.type = type;
+ ti.sa_family = sk->sk_family;
+ ti.port = inet_sk(sk)->inet_sport;
+
+ dev->netdev_ops->ndo_udp_tunnel_del(dev, &ti);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_drop_rx_port);
+
+/* Notify netdevs that UDP port started listening */
+void udp_tunnel_notify_add_rx_port(struct socket *sock, unsigned short type)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct udp_tunnel_info ti;
+ struct net_device *dev;
+
+ ti.type = type;
+ ti.sa_family = sk->sk_family;
+ ti.port = inet_sk(sk)->inet_sport;
+
+ rcu_read_lock();
+ for_each_netdev_rcu(net, dev) {
+ if (!dev->netdev_ops->ndo_udp_tunnel_add)
+ continue;
+ if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+ continue;
+ dev->netdev_ops->ndo_udp_tunnel_add(dev, &ti);
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_notify_add_rx_port);
+
+/* Notify netdevs that UDP port is no more listening */
+void udp_tunnel_notify_del_rx_port(struct socket *sock, unsigned short type)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct udp_tunnel_info ti;
+ struct net_device *dev;
+
+ ti.type = type;
+ ti.sa_family = sk->sk_family;
+ ti.port = inet_sk(sk)->inet_sport;
+
+ rcu_read_lock();
+ for_each_netdev_rcu(net, dev) {
+ if (!dev->netdev_ops->ndo_udp_tunnel_del)
+ continue;
+ if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+ continue;
+ dev->netdev_ops->ndo_udp_tunnel_del(dev, &ti);
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_notify_del_rx_port);
+
+void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
+ __be32 src, __be32 dst, __u8 tos, __u8 ttl,
+ __be16 df, __be16 src_port, __be16 dst_port,
+ bool xnet, bool nocheck)
+{
+ struct udphdr *uh;
+
+ __skb_push(skb, sizeof(*uh));
+ skb_reset_transport_header(skb);
+ uh = udp_hdr(skb);
+
+ uh->dest = dst_port;
+ uh->source = src_port;
+ uh->len = htons(skb->len);
+
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
+ udp_set_csum(nocheck, skb, src, dst, skb->len);
+
+ iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
+
+void udp_tunnel_sock_release(struct socket *sock)
+{
+ rcu_assign_sk_user_data(sock->sk, NULL);
+ kernel_sock_shutdown(sock, SHUT_RDWR);
+ sock_release(sock);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);
+
+struct metadata_dst *udp_tun_rx_dst(struct sk_buff *skb, unsigned short family,
+ __be16 flags, __be64 tunnel_id, int md_size)
+{
+ struct metadata_dst *tun_dst;
+ struct ip_tunnel_info *info;
+
+ if (family == AF_INET)
+ tun_dst = ip_tun_rx_dst(skb, flags, tunnel_id, md_size);
+ else
+ tun_dst = ipv6_tun_rx_dst(skb, flags, tunnel_id, md_size);
+ if (!tun_dst)
+ return NULL;
+
+ info = &tun_dst->u.tun_info;
+ info->key.tp_src = udp_hdr(skb)->source;
+ info->key.tp_dst = udp_hdr(skb)->dest;
+ if (udp_hdr(skb)->check)
+ info->key.tun_flags |= TUNNEL_CSUM;
+ return tun_dst;
+}
+EXPORT_SYMBOL_GPL(udp_tun_rx_dst);
+
+MODULE_LICENSE("GPL");