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/* Trivial libtrace program that counts the number of HTTP packets in a trace.
* Designed to demonstrate the use of trace_get_transport()
*/
#include "libtrace.h"
#include <stdio.h>
#include <inttypes.h>
#include <assert.h>
#include <getopt.h>
uint64_t count = 0;
static void per_packet(libtrace_packet_t *packet)
{
void *transport;
uint8_t proto;
uint32_t remaining;
libtrace_tcp_t *tcp;
/* Remember that both proto and remaining will be set for us by
* this function, so we need to pass in pointers to pre-existing
* variables. Any values in those variables will be ignored and
* replaced by trace_get_transport
*/
transport = trace_get_transport(packet, &proto, &remaining);
/* If the packet does not have a transport header, skip it */
if (transport == NULL)
return;
/* If the transport header is not TCP, skip it */
if (proto != 6)
return;
/* Cast the transport header into a TCP header */
tcp = (libtrace_tcp_t *)transport;
/* Check if either port in the TCP header is 80. Note that we have
* to byteswap the port numbers because we are reading directly out
* of the zero-copied packet */
if ((ntohs(tcp->source) == 80) || (ntohs(tcp->dest) == 80))
count += 1;
}
static void libtrace_cleanup(libtrace_t *trace, libtrace_packet_t *packet) {
/* It's very important to ensure that we aren't trying to destroy
* a NULL structure, so each of the destroy calls will only occur
* if the structure exists */
if (trace)
trace_destroy(trace);
if (packet)
trace_destroy_packet(packet);
}
int main(int argc, char *argv[])
{
/* This is essentially the same main function from readdemo.c */
libtrace_t *trace = NULL;
libtrace_packet_t *packet = NULL;
/* Ensure we have at least one argument after the program name */
if (argc < 2) {
fprintf(stderr, "Usage: %s inputURI\n", argv[0]);
return 1;
}
packet = trace_create_packet();
if (packet == NULL) {
perror("Creating libtrace packet");
libtrace_cleanup(trace, packet);
return 1;
}
trace = trace_create(argv[1]);
if (trace_is_err(trace)) {
trace_perror(trace,"Opening trace file");
libtrace_cleanup(trace, packet);
return 1;
}
if (trace_start(trace) == -1) {
trace_perror(trace,"Starting trace");
libtrace_cleanup(trace, packet);
return 1;
}
while (trace_read_packet(trace,packet)>0) {
per_packet(packet);
}
if (trace_is_err(trace)) {
trace_perror(trace,"Reading packets");
libtrace_cleanup(trace, packet);
return 1;
}
printf("Packet Count = %" PRIu64 "\n", count);
libtrace_cleanup(trace, packet);
return 0;
}
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