1 files changed, 280 insertions, 0 deletions
diff --git a/net/ipv4/udp_tunnel_core.c b/net/ipv4/udp_tunnel_core.c
new file mode 100644
index 000000000000..b1f667c52cb2
--- /dev/null
+++ b/net/ipv4/udp_tunnel_core.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <net/dst_metadata.h>
+#include <net/flow.h>
+#include <net/udp.h>
+#include <net/udp_tunnel.h>
+#include <net/inet_dscp.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;
+
+	if (cfg->bind_ifindex) {
+		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true);
+		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_unsized *)&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_unsized *)&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);
+
+static bool sk_saddr_any(struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
+#else
+	return !sk->sk_rcv_saddr;
+#endif
+}
+
+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_clear_bit(MC_LOOP, sk);
+
+	/* 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_err_rcv = cfg->encap_err_rcv;
+	udp_sk(sk)->encap_err_lookup = cfg->encap_err_lookup;
+	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(sk);
+
+	udp_tunnel_update_gro_rcv(sk, true);
+
+	if (!sk->sk_dport && !sk->sk_bound_dev_if && sk_saddr_any(sk) &&
+	    sk->sk_kern_sock)
+		udp_tunnel_update_gro_lookup(net, sk, true);
+}
+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;
+
+	ti.type = type;
+	ti.sa_family = sk->sk_family;
+	ti.port = inet_sk(sk)->inet_sport;
+
+	udp_tunnel_nic_add_port(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;
+
+	ti.type = type;
+	ti.sa_family = sk->sk_family;
+	ti.port = inet_sk(sk)->inet_sport;
+
+	udp_tunnel_nic_del_port(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;
+
+	ASSERT_RTNL();
+
+	ti.type = type;
+	ti.sa_family = sk->sk_family;
+	ti.port = inet_sk(sk)->inet_sport;
+
+	for_each_netdev(net, dev) {
+		udp_tunnel_nic_lock(dev);
+		udp_tunnel_nic_add_port(dev, &ti);
+		udp_tunnel_nic_unlock(dev);
+	}
+}
+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;
+
+	ASSERT_RTNL();
+
+	ti.type = type;
+	ti.sa_family = sk->sk_family;
+	ti.port = inet_sk(sk)->inet_sport;
+
+	for_each_netdev(net, dev) {
+		udp_tunnel_nic_lock(dev);
+		udp_tunnel_nic_del_port(dev, &ti);
+		udp_tunnel_nic_unlock(dev);
+	}
+}
+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, u16 ipcb_flags)
+{
+	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,
+		      ipcb_flags);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
+
+void udp_tunnel_sock_release(struct socket *sock)
+{
+	rcu_assign_sk_user_data(sock->sk, NULL);
+	synchronize_rcu();
+	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,
+				    const unsigned long *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)
+		__set_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
+	return tun_dst;
+}
+EXPORT_SYMBOL_GPL(udp_tun_rx_dst);
+
+struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
+				     struct net_device *dev,
+				     struct net *net, int oif,
+				     __be32 *saddr,
+				     const struct ip_tunnel_key *key,
+				     __be16 sport, __be16 dport, u8 tos,
+				     struct dst_cache *dst_cache)
+{
+	struct rtable *rt = NULL;
+	struct flowi4 fl4;
+
+#ifdef CONFIG_DST_CACHE
+	if (dst_cache) {
+		rt = dst_cache_get_ip4(dst_cache, saddr);
+		if (rt)
+			return rt;
+	}
+#endif
+
+	memset(&fl4, 0, sizeof(fl4));
+	fl4.flowi4_mark = skb->mark;
+	fl4.flowi4_proto = IPPROTO_UDP;
+	fl4.flowi4_oif = oif;
+	fl4.daddr = key->u.ipv4.dst;
+	fl4.saddr = key->u.ipv4.src;
+	fl4.fl4_dport = dport;
+	fl4.fl4_sport = sport;
+	fl4.flowi4_dscp = inet_dsfield_to_dscp(tos);
+	fl4.flowi4_flags = key->flow_flags;
+
+	rt = ip_route_output_key(net, &fl4);
+	if (IS_ERR(rt)) {
+		netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
+		return ERR_PTR(-ENETUNREACH);
+	}
+	if (rt->dst.dev == dev) { /* is this necessary? */
+		netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
+		ip_rt_put(rt);
+		return ERR_PTR(-ELOOP);
+	}
+#ifdef CONFIG_DST_CACHE
+	if (dst_cache)
+		dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
+#endif
+	*saddr = fl4.saddr;
+	return rt;
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_dst_lookup);
+
+MODULE_DESCRIPTION("IPv4 Foo over UDP tunnel driver");
+MODULE_LICENSE("GPL");