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/* GSMTAP output for Osmocom Layer2 (will only work on the host PC) */
/*
* (C) 2010 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 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include "../config.h"
#ifdef HAVE_SYS_SELECT_H
#include <osmocom/core/gsmtap_util.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/gsmtap.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/select.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/rsl.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
static struct osmo_fd gsmtap_bfd = { .fd = -1 };
static struct osmo_fd gsmtap_sink_bfd = { .fd = -1 };
static LLIST_HEAD(gsmtap_txqueue);
uint8_t chantype_rsl2gsmtap(uint8_t rsl_chantype, uint8_t link_id)
{
uint8_t ret = GSMTAP_CHANNEL_UNKNOWN;
switch (rsl_chantype) {
case RSL_CHAN_Bm_ACCHs:
ret = GSMTAP_CHANNEL_TCH_F;
break;
case RSL_CHAN_Lm_ACCHs:
ret = GSMTAP_CHANNEL_TCH_H;
break;
case RSL_CHAN_SDCCH4_ACCH:
ret = GSMTAP_CHANNEL_SDCCH4;
break;
case RSL_CHAN_SDCCH8_ACCH:
ret = GSMTAP_CHANNEL_SDCCH8;
break;
case RSL_CHAN_BCCH:
ret = GSMTAP_CHANNEL_BCCH;
break;
case RSL_CHAN_RACH:
ret = GSMTAP_CHANNEL_RACH;
break;
case RSL_CHAN_PCH_AGCH:
/* it could also be AGCH... */
ret = GSMTAP_CHANNEL_PCH;
break;
}
if (link_id & 0x40)
ret |= GSMTAP_CHANNEL_ACCH;
return ret;
}
/* receive a message from L1/L2 and put it in GSMTAP */
struct msgb *gsmtap_makemsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type,
uint8_t ss, uint32_t fn, int8_t signal_dbm,
uint8_t snr, const uint8_t *data, unsigned int len)
{
struct msgb *msg;
struct gsmtap_hdr *gh;
uint8_t *dst;
msg = msgb_alloc(sizeof(*gh) + len, "gsmtap_tx");
if (!msg)
return NULL;
gh = (struct gsmtap_hdr *) msgb_put(msg, sizeof(*gh));
gh->version = GSMTAP_VERSION;
gh->hdr_len = sizeof(*gh)/4;
gh->type = GSMTAP_TYPE_UM;
gh->timeslot = ts;
gh->sub_slot = ss;
gh->arfcn = htons(arfcn);
gh->snr_db = snr;
gh->signal_dbm = signal_dbm;
gh->frame_number = htonl(fn);
gh->sub_type = chan_type;
gh->antenna_nr = 0;
dst = msgb_put(msg, len);
memcpy(dst, data, len);
return msg;
}
/* receive a message from L1/L2 and put it in GSMTAP */
int gsmtap_sendmsg(uint16_t arfcn, uint8_t ts, uint8_t chan_type, uint8_t ss,
uint32_t fn, int8_t signal_dbm, uint8_t snr,
const uint8_t *data, unsigned int len)
{
struct msgb *msg;
/* gsmtap was never initialized, so don't try to send anything */
if (gsmtap_bfd.fd == -1)
return 0;
msg = gsmtap_makemsg(arfcn, ts, chan_type, ss, fn, signal_dbm,
snr, data, len);
if (!msg)
return -ENOMEM;
msgb_enqueue(&gsmtap_txqueue, msg);
gsmtap_bfd.when |= BSC_FD_WRITE;
return 0;
}
/* Callback from select layer if we can write to the socket */
static int gsmtap_fd_cb(struct osmo_fd *fd, unsigned int flags)
{
struct msgb *msg;
int rc;
if (!(flags & BSC_FD_WRITE))
return 0;
msg = msgb_dequeue(&gsmtap_txqueue);
if (!msg) {
/* no more messages in the queue, disable READ cb */
gsmtap_bfd.when = 0;
return 0;
}
rc = write(gsmtap_bfd.fd, msg->data, msg->len);
if (rc < 0) {
perror("writing msgb to gsmtap fd");
msgb_free(msg);
return rc;
}
if (rc != msg->len) {
perror("short write to gsmtap fd");
msgb_free(msg);
return -EIO;
}
msgb_free(msg);
return 0;
}
int gsmtap_init(uint32_t dst_ip)
{
int rc;
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(GSMTAP_UDP_PORT);
sin.sin_addr.s_addr = htonl(dst_ip);
/* create socket */
rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (rc < 0) {
perror("creating UDP socket");
return rc;
}
gsmtap_bfd.fd = rc;
rc = connect(rc, (struct sockaddr *)&sin, sizeof(sin));
if (rc < 0) {
perror("connecting UDP socket");
close(gsmtap_bfd.fd);
gsmtap_bfd.fd = -1;
return rc;
}
gsmtap_bfd.when = BSC_FD_WRITE;
gsmtap_bfd.cb = gsmtap_fd_cb;
gsmtap_bfd.data = NULL;
return osmo_fd_register(&gsmtap_bfd);
}
/* Callback from select layer if we can read from the sink socket */
static int gsmtap_sink_fd_cb(struct osmo_fd *fd, unsigned int flags)
{
int rc;
uint8_t buf[4096];
if (!(flags & BSC_FD_READ))
return 0;
rc = read(fd->fd, buf, sizeof(buf));
if (rc < 0) {
perror("reading from gsmtap sink fd");
return rc;
}
/* simply discard any data arriving on the socket */
return 0;
}
/* Create a local 'gsmtap sink' avoiding the UDP packets being rejected
* with ICMP reject messages */
int gsmtap_sink_init(uint32_t bind_ip)
{
int rc;
struct sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(GSMTAP_UDP_PORT);
sin.sin_addr.s_addr = htonl(bind_ip);
rc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (rc < 0) {
perror("creating UDP socket");
return rc;
}
gsmtap_sink_bfd.fd = rc;
rc = bind(rc, (struct sockaddr *)&sin, sizeof(sin));
if (rc < 0) {
perror("binding UDP socket");
close(gsmtap_sink_bfd.fd);
gsmtap_sink_bfd.fd = -1;
return rc;
}
gsmtap_sink_bfd.when = BSC_FD_READ;
gsmtap_sink_bfd.cb = gsmtap_sink_fd_cb;
gsmtap_sink_bfd.data = NULL;
return osmo_fd_register(&gsmtap_sink_bfd);
}
#endif /* HAVE_SYS_SELECT_H */
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