The Tcpdump Group git mirrors - tcpdump/blob - print-pppoe.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * Original code by Greg Stark <gsstark@mit.edu>
  22  */
  23
  24 #ifndef lint
  25 static const char rcsid[] =
  26 "@(#) $Header: /tcpdump/master/tcpdump/print-pppoe.c,v 1.23 2003-06-14 06:05:52 hannes Exp $ (LBL)";
  27 #endif
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <tcpdump-stdinc.h>
  34
  35 #include <stdio.h>
  36 #include <string.h>
  37
  38 #include "interface.h"
  39 #include "addrtoname.h"
  40 #include "ppp.h"
  41 #include "ethertype.h"
  42 #include "ether.h"
  43 #include "extract.h"                    /* must come after interface.h */
  44
  45 /* Codes */
  46 enum {
  47         PPPOE_PADI = 0x09,
  48         PPPOE_PADO = 0x07,
  49         PPPOE_PADR = 0x19,
  50         PPPOE_PADS = 0x65,
  51         PPPOE_PADT = 0xa7
  52 };
  53
  54 static struct tok pppoecode2str[] = {
  55         { PPPOE_PADI, "PADI" },
  56         { PPPOE_PADO, "PADO" },
  57         { PPPOE_PADR, "PADR" },
  58         { PPPOE_PADS, "PADS" },
  59         { PPPOE_PADT, "PADT" },
  60         { 0, "" }, /* PPP Data */
  61         { 0, NULL }
  62 };
  63
  64 /* Tags */
  65 enum {
  66         PPPOE_EOL = 0,
  67         PPPOE_SERVICE_NAME = 0x0101,
  68         PPPOE_AC_NAME = 0x0102,
  69         PPPOE_HOST_UNIQ = 0x0103,
  70         PPPOE_AC_COOKIE = 0x0104,
  71         PPPOE_VENDOR = 0x0105,
  72         PPPOE_RELAY_SID = 0x0110,
  73         PPPOE_SERVICE_NAME_ERROR = 0x0201,
  74         PPPOE_AC_SYSTEM_ERROR = 0x0202,
  75         PPPOE_GENERIC_ERROR = 0x0203
  76 };
  77
  78 static struct tok pppoetag2str[] = {
  79         { PPPOE_EOL, "EOL" },
  80         { PPPOE_SERVICE_NAME, "Service-Name" },
  81         { PPPOE_AC_NAME, "AC-Name" },
  82         { PPPOE_HOST_UNIQ, "Host-Uniq" },
  83         { PPPOE_AC_COOKIE, "AC-Cookie" },
  84         { PPPOE_VENDOR, "Vendor-Specific" },
  85         { PPPOE_RELAY_SID, "Relay-Session-ID" },
  86         { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
  87         { PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
  88         { PPPOE_GENERIC_ERROR, "Generic-Error" },
  89         { 0, NULL }
  90 };
  91
  92 #define PPPOE_HDRLEN 6
  93 #define MAXTAGPRINT 80
  94
  95 u_int
  96 pppoe_if_print(const struct pcap_pkthdr *h, register const u_char *p)
  97 {
  98         return (pppoe_print(p, h->len));
  99 }
 100
 101 u_int
 102 pppoe_print(register const u_char *bp, u_int length)
 103 {
 104         u_short pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid, pppoe_length;
 105         const u_char *pppoe_packet, *pppoe_payload;
 106
 107         pppoe_packet = bp;
 108         if (pppoe_packet > snapend) {
 109                 printf("[|pppoe]");
 110                 return (PPPOE_HDRLEN);
 111         }
 112
 113         pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
 114         pppoe_type  = (pppoe_packet[0] & 0x0F);
 115         pppoe_code = pppoe_packet[1];
 116         pppoe_sessionid = EXTRACT_16BITS(pppoe_packet + 2);
 117         pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
 118         pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
 119
 120         if (snapend < pppoe_payload) {
 121                 printf(" truncated PPPoE");
 122                 return (PPPOE_HDRLEN);
 123         }
 124
 125         if (pppoe_ver != 1) {
 126                 printf(" [ver %d]",pppoe_ver);
 127         }
 128         if (pppoe_type != 1) {
 129                 printf(" [type %d]",pppoe_type);
 130         }
 131
 132         printf("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
 133         if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
 134                 printf(" [len %d!]",pppoe_length);
 135         }
 136         if (pppoe_sessionid) {
 137                 printf(" [ses 0x%x]", pppoe_sessionid);
 138         }
 139
 140         if (pppoe_payload + pppoe_length < snapend && snapend-pppoe_payload+14 > 64) {
 141                 /* (small packets are probably just padded up to the ethernet
 142                    minimum of 64 bytes) */
 143                 printf(" [length %d (%d extra bytes)]",
 144                     pppoe_length, snapend - pppoe_payload - pppoe_length);
 145 #if RESPECT_PAYLOAD_LENGTH
 146                 snapend = pppoe_payload+pppoe_length;
 147 #else
 148                 /* Actual PPPoE implementations appear to ignore the payload
 149                    length and use the full ethernet frame anyways */
 150                 pppoe_length = snapend-pppoe_payload;
 151 #endif
 152
 153         }
 154
 155         if (pppoe_code) {
 156                 /* PPP session packets don't contain tags */
 157                 u_short tag_type = 0xffff, tag_len;
 158                 const u_char *p = pppoe_payload;
 159
 160                 /*
 161                  * loop invariant:
 162                  * p points to next tag,
 163                  * tag_type is previous tag or 0xffff for first iteration
 164                  */
 165                 while (tag_type && p + 4 < pppoe_payload + length &&
 166                     p + 4 < snapend) {
 167                         tag_type = EXTRACT_16BITS(p);
 168                         tag_len = EXTRACT_16BITS(p + 2);
 169                         p += 4;
 170                         /* p points to tag_value */
 171
 172                         if (tag_len) {
 173                                 unsigned isascii = 0, isgarbage = 0;
 174                                 const u_char *v = p;
 175                                 u_short l;
 176                                 char tag_str[MAXTAGPRINT];
 177                                 unsigned tag_str_len = 0;
 178
 179                                 for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
 180                                         if (*v >= 32 && *v < 127) {
 181                                                 tag_str[tag_str_len++] = *v;
 182                                                 isascii++;
 183                                         } else {
 184                                                 tag_str[tag_str_len++] = '.';
 185                                                 isgarbage++;
 186                                         }
 187                                 tag_str[tag_str_len] = 0;
 188
 189                                 if (isascii > isgarbage) {
 190                                         printf(" [%s \"%*.*s\"]",
 191                                                tok2str(pppoetag2str, "TAG-0x%x", tag_type),
 192                                                tag_str_len, tag_str_len, tag_str);
 193                                 } else {
 194                                         /* Print hex, not fast to abuse printf but this doesn't get used much */
 195                                         printf(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
 196                                         for (v=p; v<p+tag_len; v++) {
 197                                                 printf("%02.2X", *v);
 198                                         }
 199                                         printf("]");
 200                                 }
 201
 202
 203                         } else
 204                                 printf(" [%s]", tok2str(pppoetag2str,
 205                                     "TAG-0x%x", tag_type));
 206
 207                         p += tag_len;
 208                         /* p points to next tag */
 209                 }
 210                 return (0);
 211         } else {
 212                 /* PPPoE data */
 213                 printf(" ");
 214                 return (PPPOE_HDRLEN + ppp_print(pppoe_payload, pppoe_length));
 215         }
 216 }