_pppoe.c

This directory contains source code for tcpdump, a tool for network monitoring and data acquisition

/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
 * The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if 0
static const char rcsid[] =
"@(#) $Header: print-arp.c,v 1.43 97/06/15 13:20:27 leres Exp $ (LBL)";
#endif

#include <stdio.h>
#include <string.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>

#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>

#include "interfac.h"
#include "a2name.h"
#include "ppp.h"
#include "ethertyp.h"
#include "extract.h"           /* must come after interface.h */

/* Codes */
enum pppeo_codes {
     PPPOE_PADI = 0x09,
     PPPOE_PADO = 0x07,
     PPPOE_PADR = 0x19,
     PPPOE_PADS = 0x65,
     PPPOE_PADT = 0xa7
   };

static struct tok pppoecode2str[] = {
  { PPPOE_PADI, "PADI"},
  { PPPOE_PADO, "PADO"},
  { PPPOE_PADR, "PADR"},
  { PPPOE_PADS, "PADS"},
  { PPPOE_PADT, "PADT"},
  { 0, ""}, /* PPP Data */
  { 0, NULL }
};

/* Tags */
enum pppoe_tags {
     PPPOE_EOL = 0,
     PPPOE_SERVICE_NAME = 0x0101,
     PPPOE_AC_NAME = 0x0102,
     PPPOE_HOST_UNIQ = 0x0103,
     PPPOE_AC_COOKIE = 0x0104,
     PPPOE_VENDOR = 0x0105,
     PPPOE_RELAY_SID = 0x0110,
     PPPOE_SERVICE_NAME_ERROR = 0x0201,
     PPPOE_AC_SYSTEM_ERROR = 0x0202,
     PPPOE_GENERIC_ERROR = 0x0203,
   };

static struct tok pppoetag2str[] = {
  { PPPOE_EOL,                "EOL"},
  { PPPOE_SERVICE_NAME,       "Service-Name" },
  { PPPOE_AC_NAME,            "AC-Name" },
  { PPPOE_HOST_UNIQ,          "Host-Uniq" },
  { PPPOE_AC_COOKIE,          "AC-Cookie" },
  { PPPOE_VENDOR,             "Vendor-Specific" },
  { PPPOE_RELAY_SID,          "Relay-Session-ID" },
  { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
  { PPPOE_AC_SYSTEM_ERROR,    "AC-System-Error" },
  { PPPOE_GENERIC_ERROR,      "Generic-Error" },
  { 0, NULL}
};

#define PPPOE_HDRLEN 6

void pppoe_print (const u_char *bp, u_int length, u_int caplen)
{
  const struct ether_header *eh;
  const u_char *pppoe_packet, *pppoe_payload;
  u_short      pppoe_ver, pppoe_type, pppoe_code;
  u_short      pppoe_sessionid, pppoe_length;

  eh = (struct ether_header *)packetp;
  pppoe_packet = packetp+sizeof(struct ether_header);
  if (pppoe_packet > snapend)
  {
    PUTS ("[|pppoe]");
    return;
  }

  pppoe_ver       = (pppoe_packet[0]&0xF0)>>4;
  pppoe_type      = (pppoe_packet[0]&0x0F);
  pppoe_code      = (pppoe_packet[1]);
  pppoe_sessionid = (EXTRACT_16BITS(pppoe_packet+2));
  pppoe_length    = (EXTRACT_16BITS(pppoe_packet+4));
  pppoe_payload   = pppoe_packet+6;

  if (snapend < pppoe_payload)
  {
    PUTS (" truncated PPPoE");
    return;
  }

  if (pppoe_ver != 1)
     PRINTF (" [ver %d]",pppoe_ver);

  if (pppoe_type != 1)
     PRINTF (" [type %d]",pppoe_type);

  PRINTF ("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
  if (pppoe_code == PPPOE_PADI && pppoe_length > 1484-PPPOE_HDRLEN)
     PRINTF (" [len %d!]",pppoe_length);

  if (pppoe_sessionid)
     PRINTF (" [ses 0x%x]",pppoe_sessionid);

  if (pppoe_payload + pppoe_length < snapend)
  {
#if 0
    PRINTF (" [length %d (%d extra bytes)]",
            pppoe_length, snapend-pppoe_payload-pppoe_length);
    {
      const u_char *x = pppoe_payload+pppoe_length;
      default_print(x, snapend - x);
    }
#endif
    snapend = pppoe_payload+pppoe_length;
  }


  if (pppoe_code)
  {
    /* PPP session packets don't contain tags */
    u_short tag_type = -1, tag_len;
    const u_char *p = pppoe_payload;

    /* loop invariant:
     * p points to next tag,
     * tag_type is previous tag or -1 for first iteration
     */
    while (tag_type &&
           p+4 < pppoe_payload + length &&
           p+4 < snapend)
    {
      tag_type = EXTRACT_16BITS(p);
      tag_len  = EXTRACT_16BITS(p+2);
      p += 4;
      /* p points to tag_value */

      if (tag_len)
      {
        int isascii = 1;
        const u_char *v = p;

        for (v=p; v<p+tag_len; v++)
            if (*v >= 127 || *v < 32)
            {
              isascii = 0;
              break;
            }

        /* TODO print UTF8 decoded text */
        if (isascii)
             PRINTF (" [%s \"%*.*s\"]",
                     tok2str(pppoetag2str, "TAG-0x%x", tag_type),
                     tag_len < 80 ? tag_len : 80,
                     tag_len < 80 ? tag_len : 80, p);
        else PRINTF (" [%s UTF8]", tok2str(pppoetag2str,
                                   "TAG-0x%x", tag_type));
      }
      else
        PRINTF (" [%s]", tok2str(pppoetag2str, "TAG-0x%x", tag_type));

      p += tag_len;
      /* p points to next tag */
    }
  }
  else
  {
    u_short ptype;
    if (pppoe_payload[0] & 0x1)
    {
      ptype = pppoe_payload[0];
      pppoe_payload +=1;
      pppoe_length  -=1;
    }
    else if (pppoe_payload[1] & 0x1)
    {
      ptype = ntohs(*(u_short *)pppoe_payload);
      pppoe_payload +=2;
      pppoe_length  -=2;
    }
    else
    {
      PRINTF (" Invalid PPP protocol ID: %x %x",
             pppoe_payload[0],pppoe_payload[1]);
      return;
    }
    PUTCHAR (' ');

    if (ptype == PPP_IP)
         ip_print(pppoe_payload, pppoe_length);
    else if (ptype == PPP_LCP)
         lcp_print(pppoe_payload, pppoe_length, 0);
    else PRINTF ("%s ", tok2str(ppptype2str, "proto-0x%x", ptype));
  }
}