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/* PCAP support for gsm-tvoid
* (C) 2008 by Harald Welte <laforge@gnumonks.org>
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <pcap.h>
#include <errno.h>
#include <time.h>
#include "out_pcap.h"
#include "gsmtap.h"
#ifndef LINKTYPE_GSMTAP
#define LINKTYPE_GSMTAP 2342
#endif
#define TCPDUMP_MAGIC 0xa1b2c3d4
struct pcap_timeval {
int32_t tv_sec;
int32_t tv_usec;
};
struct pcap_sf_pkthdr {
struct pcap_timeval ts; /* time stamp */
u_int32_t caplen; /* lenght of portion present */
u_int32_t len; /* length of this packet */
};
static int write_pcap_file_header(int fd)
{
struct pcap_file_header pfh;
pfh.magic = TCPDUMP_MAGIC;
pfh.version_major = PCAP_VERSION_MAJOR;
pfh.version_minor = PCAP_VERSION_MINOR;
pfh.thiszone = timezone;
pfh.sigfigs = 0;
pfh.snaplen = 1024; /* FIXME */
pfh.linktype = LINKTYPE_GSMTAP;
if (write(fd, &pfh, sizeof(pfh)) < sizeof(pfh))
return -1;
return 0;
}
/* open pcap file and write header */
int open_pcap_file(char *fname)
{
int fd;
int rc;
fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0660);
if (fd < 0)
return fd;
rc = write_pcap_file_header(fd);
if (rc < 0) {
close(fd);
fd = -EIO;
}
return fd;
}
int write_pcap_packet(int fd, int arfcn, int ts, int fn,
int burst, int burst_type,
const unsigned char *data, unsigned int len)
{
unsigned char buf[8192];
struct pcap_sf_pkthdr *ph;
struct gsmtap_hdr *gh;
struct timeval tv;
int rc;
if (fd < 0)
return -EINVAL;
ph = (struct pcap_sf_pkthdr *) &buf[0];
gh = (struct gsmtap_hdr *) &buf[sizeof(struct pcap_sf_pkthdr)];
gettimeofday(&tv, NULL);
ph->ts.tv_sec = tv.tv_sec;
ph->ts.tv_usec = tv.tv_usec;
ph->caplen = ph->len = len + sizeof(struct gsmtap_hdr);
gh->version = GSMTAP_VERSION;
gh->hdr_len = sizeof(struct gsmtap_hdr)>>2;
if (burst)
gh->type = GSMTAP_TYPE_UM_BURST;
else
gh->type = GSMTAP_TYPE_UM;
gh->timeslot = ts;
gh->arfcn = htons(arfcn);
/* we don't support signal/noise yet */
gh->noise_db = gh->signal_db = 0;
gh->frame_number = htonl(fn);
gh->burst_type = burst_type & 0xff;
memcpy(buf + sizeof(*ph) + sizeof(*gh), data, len);
rc = write(fd, buf, sizeof(*ph) + sizeof(*gh) + len);
//fsync(fd);
return rc;
}
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