tcpdump.c

Raw TCP/IP interface for lwIP 0.5

/*
 * Copyright (c) 2001, Swedish Institute of Computer Science.
 * All rights reserved. 
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 * 3. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE. 
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <[e-mail]>
 *
 * $Id: tcpdump.c,v 1.2 2001/12/14 20:13:50 adam Exp $
 */

#include <stdio.h>
  
#include "netif/tcpdump.h"
#include "lwip/ip.h"
#include "lwip/tcp.h"
#include "lwip/udp.h"
#include "lwip/inet.h"

static FILE *file = NULL;

/*-----------------------------------------------------------------------------------*/
void
tcpdump_init(void)
{
  char *fname;

  fname = "/tmp/tcpdump";
  file = fopen(fname, "w");
  if(file == NULL) {
    perror("tcpdump_init: fopen");
  }
  DEBUGF(TCPDUMP_DEBUG, ("tcpdump: file %s\n", fname));
}
/*-----------------------------------------------------------------------------------*/
void
tcpdump(struct pbuf *p)
{
  struct ip_hdr *iphdr;
  struct tcp_hdr *tcphdr;
  struct udp_hdr *udphdr;
  char flags[5];
  int i;
  int len;
  int offset;

  if(file == NULL) {
    return;
  }
#ifdef IPv4  
  iphdr = p->payload;
  switch(IPH_PROTO(iphdr)) {
  case IP_PROTO_TCP:    
    tcphdr = (struct tcp_hdr *)((char *)iphdr + IP_HLEN);
    
    pbuf_header(p, -IP_HLEN);
    if(inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
			  (struct ip_addr *)&(iphdr->dest),
			  IP_PROTO_TCP, p->tot_len) != 0) {
      DEBUGF(TCPDUMP_DEBUG, ("tcpdump: IP checksum failed!\n"));
      /*    fprintf(file, "chksum 0x%lx ", tcphdr->chksum);
	    tcphdr->chksum = 0;
	    fprintf(file, "should be 0x%lx ", inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
	    (struct ip_addr *)&(iphdr->dest),
	    IP_PROTO_TCP, p->tot_len));*/
      fprintf(file, "!chksum ");
    }
    
    i = 0;
    if(TCPH_FLAGS(tcphdr) & TCP_SYN) {
      flags[i++] = 'S';
    }
    if(TCPH_FLAGS(tcphdr) & TCP_PSH) {
      flags[i++] = 'P';
    }
    if(TCPH_FLAGS(tcphdr) & TCP_FIN) {
      flags[i++] = 'F';
    }
    if(TCPH_FLAGS(tcphdr) & TCP_RST) {
      flags[i++] = 'R';
    }
    if(i == 0) {
      flags[i++] = '.';
    }
    flags[i++] = 0;    

    
    
    fprintf(file, "%d.%d.%d.%d.%u > %d.%d.%d.%d.%u: ",
	    (int)(ntohl(iphdr->src.addr) >> 24) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 16) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 8) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 0) & 0xff,
	    ntohs(tcphdr->src),
	  (int)(ntohl(iphdr->dest.addr) >> 24) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 16) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 8) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 0) & 0xff,
	    ntohs(tcphdr->dest));
    offset = TCPH_OFFSET(tcphdr) >> 4;
    
    len = ntohs(IPH_LEN(iphdr)) - offset * 4 - IP_HLEN;
    if(len != 0 || flags[0] != '.') {
      fprintf(file, "%s %lu:%lu(%u) ",
	      flags,
	      ntohl(tcphdr->seqno),
	      ntohl(tcphdr->seqno) + len,
	      len);
    }
    if(TCPH_FLAGS(tcphdr) & TCP_ACK) {
      fprintf(file, "ack %lu ",
	      ntohl(tcphdr->ackno));
    }
    fprintf(file, "wnd %u\n",
	    ntohs(tcphdr->wnd));
    
    fflush(file);
    
    pbuf_header(p, IP_HLEN);
    break;
    
  case IP_PROTO_UDP:    
    udphdr = (struct udp_hdr *)((char *)iphdr + IP_HLEN);
    
    pbuf_header(p, -IP_HLEN);
    if(inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
			  (struct ip_addr *)&(iphdr->dest),
			  IP_PROTO_UDP, p->tot_len) != 0) {
      DEBUGF(TCPDUMP_DEBUG, ("tcpdump: IP checksum failed!\n"));
      /*    fprintf(file, "chksum 0x%lx ", tcphdr->chksum);
	    tcphdr->chksum = 0;
	    fprintf(file, "should be 0x%lx ", inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src),
	    (struct ip_addr *)&(iphdr->dest),
	    IP_PROTO_TCP, p->tot_len));*/
      fprintf(file, "!chksum ");
    }
    
    fprintf(file, "%d.%d.%d.%d.%u > %d.%d.%d.%d.%u: ",
	    (int)(ntohl(iphdr->src.addr) >> 24) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 16) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 8) & 0xff,
	    (int)(ntohl(iphdr->src.addr) >> 0) & 0xff,
	    ntohs(udphdr->src),
	  (int)(ntohl(iphdr->dest.addr) >> 24) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 16) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 8) & 0xff,
	    (int)(ntohl(iphdr->dest.addr) >> 0) & 0xff,
	    ntohs(udphdr->dest));
    fprintf(file, "U ");
    len = ntohs(IPH_LEN(iphdr)) - sizeof(struct udp_hdr) - IP_HLEN;
    fprintf(file, " %d\n", len);
    
    fflush(file);
    
    pbuf_header(p, IP_HLEN);
    break;

  }
#endif /* IPv4 */
}
/*-----------------------------------------------------------------------------------*/