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/* Routines for a Virtual Um interface over GSMTAP/UDP */
/* (C) 2015 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 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 General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <net/if.h>
#include <osmocom/core/select.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/gsmtap.h>
#include "virtual_um.h"
#define VIRT_UM_MSGB_SIZE 256
static int mcast_join_group(int fd, const char *group, const char *netdev)
{
int ifindex = 0;
int rc, af;
socklen_t af_len = sizeof(af);
if (netdev) {
ifindex = if_nametoindex(netdev);
if (!ifindex)
return -1;
}
rc = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &af_len);
if (rc < 0)
return rc;
switch (af) {
case AF_INET:
{
struct ip_mreqn mr;
memset(&mr, 0, sizeof(mr));
inet_pton(AF_INET, group, &mr.imr_multiaddr);
if (ifindex)
mr.imr_ifindex = ifindex;
rc = setsockopt(fd, SOL_SOCKET, IP_ADD_MEMBERSHIP,
&mr, sizeof(mr));
}
break;
case AF_INET6:
{
struct ipv6_mreq mr;
memset(&mr, 0, sizeof(mr));
inet_pton(AF_INET6, group, &mr.ipv6mr_multiaddr);
if (ifindex)
mr.ipv6mr_interface = ifindex;
rc = setsockopt(fd, SOL_SOCKET, IPV6_ADD_MEMBERSHIP,
&mr, sizeof(mr));
}
break;
default:
rc = -1;
break;
}
return rc;
}
static int mcast_connect(int fd, const char *group, uint16_t port)
{
int rc, af;
socklen_t af_len = sizeof(af);
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
rc = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &af_len);
if (rc < 0)
return rc;
switch (af) {
case AF_INET:
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(port);
inet_pton(AF_INET, group, &sin.sin_addr);
rc = connect(fd, (struct sockaddr *) &sin, sizeof(sin));
break;
case AF_INET6:
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
sin6.sin6_port = htons(port);
inet_pton(AF_INET6, group, &sin6.sin6_addr);
rc = connect(fd, (struct sockaddr *) &sin6, sizeof(sin6));
break;
default:
return -1;
}
return rc;
}
static int virt_um_fd_cb(struct osmo_fd *ofd, unsigned int what)
{
struct virt_um_inst *vui = ofd->data;
if (what & BSC_FD_READ) {
struct msgb *msg = msgb_alloc(VIRT_UM_MSGB_SIZE, "Virtual UM Rx");
int rc;
rc = read(ofd->fd, msgb_data(msg), msgb_tailroom(msg));
if (rc > 0) {
msgb_put(msg, rc);
vui->recv_cb(vui, msg);
} else {
vui->recv_cb(vui, NULL);
osmo_fd_unregister(ofd);
close(ofd->fd);
ofd->fd = -1;
ofd->when = 0;
}
}
return 0;
}
struct virt_um_inst *virt_um_init(void *ctx, const char *group, uint16_t port,
const char *netdev, void *priv,
void (*recv_cb)(struct virt_um_inst *vui, struct msgb *msg))
{
struct virt_um_inst *vui;
int fd, rc;
if (!port)
port = GSMTAP_UDP_PORT;
if (!group)
group = "239.0.47.29";
/* crate a socked and bind it to the multicast group. Do NOT
* specify a fixed port locally, to make stack choose a random
* free UDP port. */
fd = osmo_sock_init(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, group,
0, OSMO_SOCK_F_BIND);
if (fd < 0)
return NULL;
/* join the multicast group */
rc = mcast_join_group(fd, group, netdev);
if (rc < 0) {
close(fd);
return NULL;
}
/* and finally also connect */
rc = mcast_connect(fd, group, port);
if (rc < 0) {
close(fd);
return NULL;
}
vui = talloc_zero(ctx, struct virt_um_inst);
vui->priv = priv;
vui->recv_cb = recv_cb;
vui->ofd.data = vui;
vui->ofd.fd = fd;
vui->ofd.when = BSC_FD_READ;
vui->ofd.cb = virt_um_fd_cb;
osmo_fd_register(&vui->ofd);
return vui;
}
void virt_um_destroy(struct virt_um_inst *vui)
{
struct osmo_fd *ofd = &vui->ofd;
osmo_fd_unregister(ofd);
close(ofd->fd);
ofd->fd = -1;
ofd->when = 0;
talloc_free(vui);
}
int virt_um_write_msg(struct virt_um_inst *vui, struct msgb *msg)
{
int rc;
rc = write(vui->ofd.fd, msgb_data(msg), msgb_length(msg));
msgb_free(msg);
return rc;
}
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