udp: Add udp_sock_create for UDP tunnels to open listener socket

Added udp_tunnel.c which can contain some common functions for UDP
tunnels. The first function in this is udp_sock_create which is used
to open the listener port for a UDP tunnel.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
new file mode 100644 (file)
index 0000000..ffd69cb
--- /dev/null
+++ b/include/net/udp_tunnel.h
@@ -0,0 +1,32 @@
+#ifndef __NET_UDP_TUNNEL_H
+#define __NET_UDP_TUNNEL_H
+
+struct udp_port_cfg {
+       u8                      family;
+
+       /* Used only for kernel-created sockets */
+       union {
+               struct in_addr          local_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+               struct in6_addr         local_ip6;
+#endif
+       };
+
+       union {
+               struct in_addr          peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+               struct in6_addr         peer_ip6;
+#endif
+       };
+
+       __be16                  local_udp_port;
+       __be16                  peer_udp_port;
+       unsigned int            use_udp_checksums:1,
+                               use_udp6_tx_checksums:1,
+                               use_udp6_rx_checksums:1;
+};
+
+int udp_sock_create(struct net *net, struct udp_port_cfg *cfg,
+                   struct socket **sockp);
+
+#endif

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 05c57f0..dbc10d8 100644 (file)
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -307,6 +307,10 @@ config NET_IPVTI
          the notion of a secure tunnel for IPSEC and then use routing protocol
          on top.
 
+config NET_UDP_TUNNEL
+       tristate
+       default n
+
 config INET_AH
        tristate "IP: AH transformation"
        select XFRM_ALGO

diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index f032688..8ee1cd4 100644 (file)
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_NET_IPIP) += ipip.o
 gre-y := gre_demux.o
 obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
 obj-$(CONFIG_NET_IPGRE) += ip_gre.o
+obj-$(CONFIG_NET_UDP_TUNNEL) += udp_tunnel.o
 obj-$(CONFIG_NET_IPVTI) += ip_vti.o
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
 obj-$(CONFIG_INET_AH) += ah4.o

diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
new file mode 100644 (file)
index 0000000..61ec1a6
--- /dev/null
+++ b/net/ipv4/udp_tunnel.c
@@ -0,0 +1,100 @@
+#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/udp.h>
+#include <net/udp_tunnel.h>
+#include <net/net_namespace.h>
+
+int udp_sock_create(struct net *net, struct udp_port_cfg *cfg,
+                   struct socket **sockp)
+{
+       int err = -EINVAL;
+       struct socket *sock = NULL;
+
+#if IS_ENABLED(CONFIG_IPV6)
+       if (cfg->family == AF_INET6) {
+               struct sockaddr_in6 udp6_addr;
+
+               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);
+       } else
+#endif
+       if (cfg->family == AF_INET) {
+               struct sockaddr_in udp_addr;
+
+               err = sock_create_kern(AF_INET, SOCK_DGRAM, 0, &sock);
+               if (err < 0)
+                       goto error;
+
+               sk_change_net(sock->sk, net);
+
+               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;
+       } else {
+               return -EPFNOSUPPORT;
+       }
+
+
+       *sockp = sock;
+
+       return 0;
+
+error:
+       if (sock) {
+               kernel_sock_shutdown(sock, SHUT_RDWR);
+               sk_release_kernel(sock->sk);
+       }
+       *sockp = NULL;
+       return err;
+}
+EXPORT_SYMBOL(udp_sock_create);
+
+MODULE_LICENSE("GPL");