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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 <osmocom/core/select.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/gsmtap.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
#include <virtphy/osmo_mcast_sock.h>
#include <virtphy/virtual_um.h>
#include <unistd.h>
/**
* Virtual UM interface file descriptor callback.
* Should be called by select.c when the fd is ready for reading.
*/
static int virt_um_fd_cb(struct osmo_fd *ofd, unsigned int what)
{
struct virt_um_inst *vui = ofd->data;
// check if the read flag is set
if (what & BSC_FD_READ) {
// allocate message buffer of specified size
struct msgb *msg = msgb_alloc(VIRT_UM_MSGB_SIZE,
"Virtual UM Rx");
int rc;
// read message from fd in message buffer
rc = mcast_bidir_sock_rx(vui->mcast_sock, msgb_data(msg),
msgb_tailroom(msg));
// rc is number of bytes actually read
if (rc > 0) {
msgb_put(msg, rc);
msg->l1h = msgb_data(msg);
// call the l1 callback function for a received msg
vui->recv_cb(vui, msg);
} else {
// TODO: this kind of error handling might be a bit harsh
vui->recv_cb(vui, NULL);
// Unregister fd from select loop
osmo_fd_unregister(ofd);
close(ofd->fd);
ofd->fd = -1;
ofd->when = 0;
}
}
return 0;
}
struct virt_um_inst *virt_um_init(
void *ctx, char *tx_mcast_group, uint16_t tx_mcast_port,
char *rx_mcast_group, uint16_t rx_mcast_port,
void (*recv_cb)(struct virt_um_inst *vui, struct msgb *msg))
{
struct virt_um_inst *vui = talloc_zero(ctx, struct virt_um_inst);
vui->mcast_sock = mcast_bidir_sock_setup(ctx, tx_mcast_group,
tx_mcast_port, rx_mcast_group, rx_mcast_port, 1,
virt_um_fd_cb, vui);
vui->recv_cb = recv_cb;
return vui;
}
void virt_um_destroy(struct virt_um_inst *vui)
{
mcast_bidir_sock_close(vui->mcast_sock);
talloc_free(vui);
}
/**
* Write msg to to multicast socket and free msg afterwards
*/
int virt_um_write_msg(struct virt_um_inst *vui, struct msgb *msg)
{
int rc;
rc = mcast_bidir_sock_tx(vui->mcast_sock, msgb_data(msg),
msgb_length(msg));
msgb_free(msg);
return rc;
}
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