/*
  Copyright (C) JAEHYUK CHO
  All rights reserved.
  Code by JaeHyuk Cho <mailto:minzkn@minzkn.com>
*/

#if !defined(_ISOC99_SOURCE)
# define _ISOC99_SOURCE (1L)
#endif

#if !defined(_GNU_SOURCE)
# define _GNU_SOURCE (1L)
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <arpa/inet.h>

#include <linux/filter.h>
#include <linux/if_ether.h>
#include <linux/if.h>

int main(int s_argc, char **s_argv);

static void * (__mz_dump_ex__)(size_t s_s, size_t s_d, void * s_da, size_t s_si)
{ size_t s_o, s_w, s_lo; unsigned char s_b[ 16 + 1 ];
 if(s_da == NULL)return(NULL); s_b[sizeof(s_b) - 1] = (unsigned char)'\0';
 for(s_o = (size_t)0;s_o < s_si;s_o += (size_t)16){
  s_w = ((s_si - s_o) <= ((size_t)16)) ? (s_si - s_o) : ((size_t)16);
  (void)fprintf(stdout, "%08lX", (unsigned long)(s_d + s_o));
  for(s_lo = (size_t)0;s_lo < s_w;s_lo++){
   if(s_lo == ((size_t)(16 >> 1)))(void)fputs(" | ", stdout);
   else (void)fputs(" ", stdout);
   s_b[s_lo] = *(((unsigned char *)s_da) + (s_s + s_o + s_lo));
   (void)fprintf(stdout, "%02X", (int)s_b[s_lo]);
   if((s_b[s_lo] & ((unsigned char)(1 << 7))) || (s_b[s_lo] < ((unsigned char)' ')) ||
      (s_b[s_lo] == ((unsigned char)0x7f)))s_b[s_lo] = (unsigned char)'.';}
  while(s_lo < ((size_t)16)){
   if(s_lo == ((size_t)(16 >> 1)))(void)fputs("     ", stdout);
   else (void)fputs("   ", stdout);
   s_b[s_lo] = (unsigned char)' '; s_lo++;}
  (void)fprintf(stdout, " [%s]\n", (char *)(&s_b[0]));}
 return(s_da);
}
static __inline void * (mz_dump_ex)(size_t s_seek_offset, size_t s_display_offset, void * s_data, size_t s_size)
{ return(__mz_dump_ex__(s_seek_offset, s_display_offset, s_data, s_size)); }
#define mz_dump(m_data,m_size) mz_dump_ex((size_t)0,(size_t)0,(void *)(m_data),(size_t)(m_size))

int main(int s_argc, char **s_argv)
{
    int s_socket;
    unsigned char s_buffer[ 64 << 10 ];
    ssize_t s_recv_bytes;
# if 1L
    struct sock_filter s_bpf_code[] = { /* tcpdump -dd 'tcp[tcpflags] & (tcp-syn) != 0' */
        { 0x28, 0, 0, 0x0000000c },
        { 0x15, 0, 8, 0x00000800 },
        { 0x30, 0, 0, 0x00000017 },
        { 0x15, 0, 6, 0x00000006 },
        { 0x28, 0, 0, 0x00000014 },
        { 0x45, 4, 0, 0x00001fff },
        { 0xb1, 0, 0, 0x0000000e },
        { 0x50, 0, 0, 0x0000001b },
        { 0x45, 0, 1, 0x00000002 },
        { 0x6, 0, 0, 0x0000ffff },
        { 0x6, 0, 0, 0x00000000 },
    };
# else
    struct sock_filter s_bpf_code[] = { /* tcpdump -dd tcp */
        { 0x28, 0, 0, 0x0000000c },
        { 0x15, 0, 2, 0x000086dd },
        { 0x30, 0, 0, 0x00000014 },
        { 0x15, 3, 4, 0x00000006 },
        { 0x15, 0, 3, 0x00000800 },
        { 0x30, 0, 0, 0x00000017 },
        { 0x15, 0, 1, 0x00000006 },
        { 0x6, 0, 0, 0x00000800 },
        { 0x6, 0, 0, 0x00000000 }
    };
# endif
    struct sock_fprog s_filter;
    int s_check;

    (void)s_argc;
    (void)s_argv;

    s_socket = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP));
    if(s_socket == (-1)) {
        perror("socket");
        return(EXIT_FAILURE);
    }

    s_filter.len = sizeof(s_bpf_code) / sizeof(struct sock_filter);
    s_filter.filter = s_bpf_code;
    s_check = setsockopt(s_socket, SOL_SOCKET, SO_ATTACH_FILTER, (const void *)(&s_filter), (socklen_t)sizeof(s_filter));

    for(;;) {
        s_recv_bytes = recv(s_socket, (void *)(&s_buffer[0]), sizeof(s_buffer), 0);
        if(s_recv_bytes == ((ssize_t)(-1))) {
            perror("recv");
            break;
        }

        (void)fprintf(stdout, "recv %ld bytes\n", (long)s_recv_bytes);
        mz_dump(s_buffer, s_recv_bytes);
    }

    (void)close(s_socket);

    return(EXIT_SUCCESS);
}

/* vim: set expandtab: */
/* End of source */