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/* Command line utility to create GTP link */
/* (C) 2014 by sysmocom - s.f.m.c. GmbH
* (C) 2016 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* Author: Pablo Neira Ayuso <pablo@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <libmnl/libmnl.h>
#include <linux/if.h>
#include <linux/if_link.h>
#include <linux/rtnetlink.h>
#include <linux/gtp.h>
#include <linux/if_link.h>
#include <libgtpnl/gtpnl.h>
struct gtp_server_sock {
int family;
int fd1;
int fd2;
socklen_t len;
struct {
union {
struct sockaddr_in in;
struct sockaddr_in6 in6;
} fd1;
union {
struct sockaddr_in in;
struct sockaddr_in6 in6;
} fd2;
} sockaddr;
};
static void setup_sockaddr_in(struct sockaddr_in *sockaddr, uint16_t port)
{
sockaddr->sin_family = AF_INET;
sockaddr->sin_port = htons(port);
sockaddr->sin_addr.s_addr = INADDR_ANY;
}
static void setup_sockaddr_in6(struct sockaddr_in6 *sockaddr, uint16_t port)
{
sockaddr->sin6_family = AF_INET6;
sockaddr->sin6_port = htons(port);
sockaddr->sin6_addr = in6addr_any;
}
static int setup_socket(struct gtp_server_sock *gtp_sock, int family)
{
int fd1 = socket(family, SOCK_DGRAM, 0);
int fd2 = socket(family, SOCK_DGRAM, 0);
if (fd1 < 0 || fd2 < 0)
return -1;
memset(gtp_sock, 0, sizeof(*gtp_sock));
gtp_sock->family = family;
gtp_sock->fd1 = fd1;
gtp_sock->fd2 = fd2;
switch (family) {
case AF_INET:
gtp_sock->len = sizeof(struct sockaddr_in);
setup_sockaddr_in(>p_sock->sockaddr.fd1.in, 3386);
setup_sockaddr_in(>p_sock->sockaddr.fd2.in, 2152);
break;
case AF_INET6:
gtp_sock->len = sizeof(struct sockaddr_in6);
setup_sockaddr_in6(>p_sock->sockaddr.fd1.in6, 3386);
setup_sockaddr_in6(>p_sock->sockaddr.fd2.in6, 2152);
break;
}
return 0;
}
int main(int argc, char *argv[])
{
char buf[MNL_SOCKET_BUFFER_SIZE];
struct gtp_server_sock gtp_sock;
int ret, sgsn_mode = 0, family;
if (argc < 3) {
printf("Usage: %s add <device> <family> [--sgsn]\n", argv[0]);
printf(" %s del <device>\n", argv[0]);
exit(EXIT_FAILURE);
}
if (!strcmp(argv[1], "del")) {
printf("destroying gtp interface...\n");
if (gtp_dev_destroy(argv[2]) < 0)
perror("gtp_dev_destroy");
return 0;
} else if (!strcmp(argv[1], "add")) {
if (argc < 4) {
printf("Usage: %s add <device> <family> [--sgsn]\n", argv[0]);
exit(EXIT_FAILURE);
}
if (argc == 5 && !strcmp(argv[4], "--sgsn"))
sgsn_mode = 1;
}
if (!strcmp(argv[3], "ip"))
family = AF_INET;
else if (!strcmp(argv[3], "ip6"))
family = AF_INET6;
else {
fprintf(stderr, "unsupport family `%s', expecting `ip' or `ip6'\n",
argv[3]);
exit(EXIT_FAILURE);
}
if (setup_socket(>p_sock, family) < 0) {
perror("socket");
exit(EXIT_FAILURE);
}
if (bind(gtp_sock.fd1, (struct sockaddr *) >p_sock.sockaddr.fd1, gtp_sock.len) < 0) {
perror("bind");
exit(EXIT_FAILURE);
}
if (bind(gtp_sock.fd2, (struct sockaddr *) >p_sock.sockaddr.fd2, gtp_sock.len) < 0) {
perror("bind");
exit(EXIT_FAILURE);
}
if (sgsn_mode)
ret = gtp_dev_create_sgsn(-1, argv[2], gtp_sock.fd1, gtp_sock.fd2);
else
ret = gtp_dev_create(-1, argv[2], gtp_sock.fd1, gtp_sock.fd2);
if (ret < 0) {
perror("cannot create GTP device\n");
exit(EXIT_FAILURE);
}
fprintf(stderr, "WARNING: attaching dummy socket descriptors. Keep "
"this process running for testing purposes.\n");
while (1) {
union {
struct sockaddr_in addr;
struct sockaddr_in6 addr6;
} sock;
ret = recvfrom(gtp_sock.fd1, buf, sizeof(buf), 0,
(struct sockaddr *)&sock, >p_sock.len);
printf("received %d bytes via UDP socket\n", ret);
}
return 0;
}
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