remarkable-linux/net/ipv4/udp_tunnel.c

#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_create4(struct net *net, struct udp_port_cfg *cfg,
		     struct socket **sockp)
{
	int err = -EINVAL;
	struct socket *sock = NULL;
	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;

	*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_create4);

MODULE_LICENSE("GPL");