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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <pcap.h>
#include "gsmstack.h"
#include "gsmtap.h"
/* source_pcap_burst.c: read a PCAP file with GSMTAP_UM_BURST packets
* and feed them into the stack.
*
* (C) 2008 by Harald Welte <laforge@gnumonks.org>
*
* TODO:
* fix PCAP endianness
*/
static struct gsm_rf_chan *rfchans[NR_ARFCN];
static int read_pcap_hdr(int fd)
{
int rc;
struct pcap_file_header pfh;
rc = read(fd, &pfh, sizeof(pfh));
if (rc < sizeof(pfh))
return -EIO;
if (pfh.magic != TCPDUMP_MAGIC)
return -EINVAL;
if (pfh.linktype != LINKTYPE_GSMTAP)
return -EINVAL;
return 0;
}
static int send_burst(struct gsmtap_hdr *gh, int burst_len,
struct timeval *tv)
{
unsigned char *data = (unsigned char *)gh + sizeof(*gh);
struct gsm_burst burst;
struct gsm_rf_chan *rfchan;
struct gsm_phys_chan *pchan;
unsigned int arfcn;
arfcn = ntohs(gh->arfcn);
/* Create new RF channel structure if we've not seen this ARFCN
* before */
if (!rfchans[arfcn]) {
rfchans[arfcn] = gsm_init_rfchan(arfcn);
if (!rfchans[arfcn]) {
fprintf(stderr, "cannot init rfchan ARFCN=%u\n",
arfcn);
return -EINVAL;
}
}
rfchan = rfchans[arfcn];
pchan = &rfchan->phys_chan[gh->timeslot];
memset(&burst, 0, sizeof(burst));
burst.phys_chan = pchan;
burst.burst_type = gh->burst_type;
burst.rx_frame_nr = ntohl(gh->frame_number);
memcpy(&burst.rx_time, tv, sizeof(burst.rx_time));
memcpy(burst.decoded, data, burst_len);
return gsm_rx_burst(&burst, 0);
}
/* fills 'buf' with gsmtap_hdr and payload, returns length of payload */
static int read_one_pkt(int fd, unsigned char *buf, int bufsize,
struct timeval *tv)
{
struct pcap_sf_pkthdr pkthdr;
struct gsmtap_hdr *gh = (struct gsmtap_hdr *) buf;
int len, burstlen;
len = read(fd, &pkthdr, sizeof(pkthdr));
if (len < sizeof(pkthdr))
return -1;
/* FIXME: ntohl on caplen and len? */
if (pkthdr.caplen < sizeof(*gh))
return -2;
if (pkthdr.len > pkthdr.caplen)
return -3;
if (bufsize < pkthdr.len)
return -4;
if (tv) {
tv->tv_sec = pkthdr.ts.tv_sec;
tv->tv_usec = pkthdr.ts.tv_usec;
}
len = read(fd, buf, pkthdr.caplen);
if (len < pkthdr.caplen)
return -5;
if (gh->version != GSMTAP_VERSION ||
gh->type != GSMTAP_TYPE_UM_BURST)
return -6;
return pkthdr.caplen - sizeof(*gh);
}
int main(int argc, char **argv)
{
char *fname;
int fd, rc;
if (argc != 2) {
fprintf(stderr, "please specify pcap filename\n");
exit(2);
}
fname = argv[1];
fd = open(fname, O_RDONLY);
if (fd < 0) {
perror("open");
exit(1);
}
rc = read_pcap_hdr(fd);
if (rc < 0) {
perror("pcap_hdr");
exit(1);
}
while (1) {
unsigned char buf[1024];
struct timeval tv;
int burst_len;
burst_len = read_one_pkt(fd, buf, sizeof(buf), &tv);
if (burst_len < 0) {
fprintf(stderr, "read_one_pkt() = %d\n", burst_len);
exit(3);
}
rc = send_burst((struct gsmtap_hdr *)buf, burst_len, &tv);
}
}
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