contrib/tcpdump/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 /* \summary: PPP-over-Ethernet (PPPoE) printer */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <netdissect-stdinc.h>
  31
  32 #include "netdissect.h"
  33 #include "extract.h"
  34
  35 /* Codes */
  36 enum {
  37         PPPOE_PADI = 0x09,
  38         PPPOE_PADO = 0x07,
  39         PPPOE_PADR = 0x19,
  40         PPPOE_PADS = 0x65,
  41         PPPOE_PADT = 0xa7
  42 };
  43
  44 static const struct tok pppoecode2str[] = {
  45         { PPPOE_PADI, "PADI" },
  46         { PPPOE_PADO, "PADO" },
  47         { PPPOE_PADR, "PADR" },
  48         { PPPOE_PADS, "PADS" },
  49         { PPPOE_PADT, "PADT" },
  50         { 0, "" }, /* PPP Data */
  51         { 0, NULL }
  52 };
  53
  54 /* Tags */
  55 enum {
  56         PPPOE_EOL = 0,
  57         PPPOE_SERVICE_NAME = 0x0101,
  58         PPPOE_AC_NAME = 0x0102,
  59         PPPOE_HOST_UNIQ = 0x0103,
  60         PPPOE_AC_COOKIE = 0x0104,
  61         PPPOE_VENDOR = 0x0105,
  62         PPPOE_RELAY_SID = 0x0110,
  63         PPPOE_MAX_PAYLOAD = 0x0120,
  64         PPPOE_SERVICE_NAME_ERROR = 0x0201,
  65         PPPOE_AC_SYSTEM_ERROR = 0x0202,
  66         PPPOE_GENERIC_ERROR = 0x0203
  67 };
  68
  69 static const struct tok pppoetag2str[] = {
  70         { PPPOE_EOL, "EOL" },
  71         { PPPOE_SERVICE_NAME, "Service-Name" },
  72         { PPPOE_AC_NAME, "AC-Name" },
  73         { PPPOE_HOST_UNIQ, "Host-Uniq" },
  74         { PPPOE_AC_COOKIE, "AC-Cookie" },
  75         { PPPOE_VENDOR, "Vendor-Specific" },
  76         { PPPOE_RELAY_SID, "Relay-Session-ID" },
  77         { PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
  78         { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
  79         { PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
  80         { PPPOE_GENERIC_ERROR, "Generic-Error" },
  81         { 0, NULL }
  82 };
  83
  84 #define PPPOE_HDRLEN 6
  85 #define MAXTAGPRINT 80
  86
  87 u_int
  88 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, register const u_char *p)
  89 {
  90         return (pppoe_print(ndo, p, h->len));
  91 }
  92
  93 u_int
  94 pppoe_print(netdissect_options *ndo, register const u_char *bp, u_int length)
  95 {
  96         uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
  97         u_int pppoe_length;
  98         const u_char *pppoe_packet, *pppoe_payload;
  99
 100         if (length < PPPOE_HDRLEN) {
 101                 ND_PRINT((ndo, "truncated-pppoe %u", length));
 102                 return (length);
 103         }
 104         length -= PPPOE_HDRLEN;
 105         pppoe_packet = bp;
 106         ND_TCHECK2(*pppoe_packet, PPPOE_HDRLEN);
 107         pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
 108         pppoe_type  = (pppoe_packet[0] & 0x0F);
 109         pppoe_code = pppoe_packet[1];
 110         pppoe_sessionid = EXTRACT_16BITS(pppoe_packet + 2);
 111         pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
 112         pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
 113
 114         if (pppoe_ver != 1) {
 115                 ND_PRINT((ndo, " [ver %d]",pppoe_ver));
 116         }
 117         if (pppoe_type != 1) {
 118                 ND_PRINT((ndo, " [type %d]",pppoe_type));
 119         }
 120
 121         ND_PRINT((ndo, "PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code)));
 122         if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
 123                 ND_PRINT((ndo, " [len %u!]",pppoe_length));
 124         }
 125         if (pppoe_length > length) {
 126                 ND_PRINT((ndo, " [len %u > %u!]", pppoe_length, length));
 127                 pppoe_length = length;
 128         }
 129         if (pppoe_sessionid) {
 130                 ND_PRINT((ndo, " [ses 0x%x]", pppoe_sessionid));
 131         }
 132
 133         if (pppoe_code) {
 134                 /* PPP session packets don't contain tags */
 135                 u_short tag_type = 0xffff, tag_len;
 136                 const u_char *p = pppoe_payload;
 137
 138                 /*
 139                  * loop invariant:
 140                  * p points to current tag,
 141                  * tag_type is previous tag or 0xffff for first iteration
 142                  */
 143                 while (tag_type && p < pppoe_payload + pppoe_length) {
 144                         ND_TCHECK2(*p, 4);
 145                         tag_type = EXTRACT_16BITS(p);
 146                         tag_len = EXTRACT_16BITS(p + 2);
 147                         p += 4;
 148                         /* p points to tag_value */
 149
 150                         if (tag_len) {
 151                                 unsigned ascii_count = 0, garbage_count = 0;
 152                                 const u_char *v;
 153                                 char tag_str[MAXTAGPRINT];
 154                                 unsigned tag_str_len = 0;
 155
 156                                 /* TODO print UTF-8 decoded text */
 157                                 ND_TCHECK2(*p, tag_len);
 158                                 for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
 159                                         if (*v >= 32 && *v < 127) {
 160                                                 tag_str[tag_str_len++] = *v;
 161                                                 ascii_count++;
 162                                         } else {
 163                                                 tag_str[tag_str_len++] = '.';
 164                                                 garbage_count++;
 165                                         }
 166                                 tag_str[tag_str_len] = 0;
 167
 168                                 if (ascii_count > garbage_count) {
 169                                         ND_PRINT((ndo, " [%s \"%*.*s\"]",
 170                                                tok2str(pppoetag2str, "TAG-0x%x", tag_type),
 171                                                (int)tag_str_len,
 172                                                (int)tag_str_len,
 173                                                tag_str));
 174                                 } else {
 175                                         /* Print hex, not fast to abuse printf but this doesn't get used much */
 176                                         ND_PRINT((ndo, " [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type)));
 177                                         for (v=p; v<p+tag_len; v++) {
 178                                                 ND_PRINT((ndo, "%02X", *v));
 179                                         }
 180                                         ND_PRINT((ndo, "]"));
 181                                 }
 182
 183
 184                         } else
 185                                 ND_PRINT((ndo, " [%s]", tok2str(pppoetag2str,
 186                                     "TAG-0x%x", tag_type)));
 187
 188                         p += tag_len;
 189                         /* p points to next tag */
 190                 }
 191                 return (0);
 192         } else {
 193                 /* PPPoE data */
 194                 ND_PRINT((ndo, " "));
 195                 return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
 196         }
 197
 198 trunc:
 199         ND_PRINT((ndo, "[|pppoe]"));
 200         return (PPPOE_HDRLEN);
 201 }