/*
 * Written by Pejman Moghadam / 1401-02-30
 * Public domain.
 *
 */

/* gcc src.c -lpcap */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <pcap/pcap.h>

void show_packet(char *buf, int len)
{
    unsigned char ch;
    int i, j, k, space;

    printf("\n");
    for (i = 0; i < len; i+=16) {
        printf("\t0x%04x  ", i);
        for (j = i; j < i+16 && j < len; j++) {
            ch = (unsigned char)buf[j];
            printf("%02X ", ch);
        }
 
        if (j == i+16)
            space = 1;
        else
            space = 1 + (16*3) - (j-i)*3;
 
        for (k = 0; k < space; k++)
            printf(" ");
 
        for (j = i; j < i+16 && j < len; j++) {
            ch = (unsigned char)buf[j];
            if (ch <= 32 || ch >= 127)
                ch = '.';
            printf("%c", ch);
        }
        printf("\n");
    }
    printf("\n");
}

void packet_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes)
{
    static int packet_count = 0;
    printf("Packet: %d , Size: %d\n", ++packet_count, h->len);
    show_packet((char *)bytes, h->len);
}

int main()
{
    pcap_t *p;
    char errbuf[PCAP_ERRBUF_SIZE];
    p = pcap_open_offline("capture.pcap", errbuf);
    if (p == NULL) {
        fprintf(stderr, "\npcap_open_offline() failed: %s\n", errbuf);
        exit(EXIT_FAILURE);
    }

    if (pcap_loop(p, 0, packet_handler, NULL) < 0) {
        fprintf(stderr, "\npcap_loop() failed: %s\n", pcap_geterr(p));
        exit(EXIT_FAILURE);
    }

    return 0;
}