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 #include <sys/cdefs.h> 25 #ifndef lint 26 __RCSID("$NetBSD: print-pppoe.c,v 1.9 2024/09/02 16:15:32 christos Exp $"); 27 #endif 28 29 /* \summary: PPP-over-Ethernet (PPPoE) printer */ 30 31 #include <config.h> 32 33 #include "netdissect-stdinc.h" 34 35 #include "netdissect-ctype.h" 36 37 #define ND_LONGJMP_FROM_TCHECK 38 #include "netdissect.h" 39 #include "extract.h" 40 41 /* Codes */ 42 enum { 43 PPPOE_PADI = 0x09, 44 PPPOE_PADO = 0x07, 45 PPPOE_PADR = 0x19, 46 PPPOE_PADS = 0x65, 47 PPPOE_PADT = 0xa7 48 }; 49 50 static const struct tok pppoecode2str[] = { 51 { PPPOE_PADI, "PADI" }, 52 { PPPOE_PADO, "PADO" }, 53 { PPPOE_PADR, "PADR" }, 54 { PPPOE_PADS, "PADS" }, 55 { PPPOE_PADT, "PADT" }, 56 { 0, "" }, /* PPP Data */ 57 { 0, NULL } 58 }; 59 60 /* Tags */ 61 enum { 62 PPPOE_EOL = 0, 63 PPPOE_SERVICE_NAME = 0x0101, 64 PPPOE_AC_NAME = 0x0102, 65 PPPOE_HOST_UNIQ = 0x0103, 66 PPPOE_AC_COOKIE = 0x0104, 67 PPPOE_VENDOR = 0x0105, 68 PPPOE_RELAY_SID = 0x0110, 69 PPPOE_MAX_PAYLOAD = 0x0120, 70 PPPOE_SERVICE_NAME_ERROR = 0x0201, 71 PPPOE_AC_SYSTEM_ERROR = 0x0202, 72 PPPOE_GENERIC_ERROR = 0x0203 73 }; 74 75 static const struct tok pppoetag2str[] = { 76 { PPPOE_EOL, "EOL" }, 77 { PPPOE_SERVICE_NAME, "Service-Name" }, 78 { PPPOE_AC_NAME, "AC-Name" }, 79 { PPPOE_HOST_UNIQ, "Host-Uniq" }, 80 { PPPOE_AC_COOKIE, "AC-Cookie" }, 81 { PPPOE_VENDOR, "Vendor-Specific" }, 82 { PPPOE_RELAY_SID, "Relay-Session-ID" }, 83 { PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" }, 84 { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" }, 85 { PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" }, 86 { PPPOE_GENERIC_ERROR, "Generic-Error" }, 87 { 0, NULL } 88 }; 89 90 #define PPPOE_HDRLEN 6 91 #define MAXTAGPRINT 80 92 93 void 94 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 95 { 96 ndo->ndo_protocol = "pppoe"; 97 ndo->ndo_ll_hdr_len += pppoe_print(ndo, p, h->len); 98 } 99 100 u_int 101 pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length) 102 { 103 uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid; 104 u_int pppoe_length; 105 const u_char *pppoe_packet, *pppoe_payload; 106 107 ndo->ndo_protocol = "pppoe"; 108 if (length < PPPOE_HDRLEN) { 109 ND_PRINT(" (length %u < %u)", length, PPPOE_HDRLEN); 110 goto invalid; 111 } 112 length -= PPPOE_HDRLEN; 113 pppoe_packet = bp; 114 ND_TCHECK_LEN(pppoe_packet, PPPOE_HDRLEN); 115 pppoe_ver = (GET_U_1(pppoe_packet) & 0xF0) >> 4; 116 pppoe_type = (GET_U_1(pppoe_packet) & 0x0F); 117 pppoe_code = GET_U_1(pppoe_packet + 1); 118 pppoe_sessionid = GET_BE_U_2(pppoe_packet + 2); 119 pppoe_length = GET_BE_U_2(pppoe_packet + 4); 120 pppoe_payload = pppoe_packet + PPPOE_HDRLEN; 121 122 if (pppoe_ver != 1) { 123 ND_PRINT(" [ver %u]",pppoe_ver); 124 } 125 if (pppoe_type != 1) { 126 ND_PRINT(" [type %u]",pppoe_type); 127 } 128 129 ND_PRINT("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code)); 130 if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) { 131 ND_PRINT(" [len %u!]",pppoe_length); 132 } 133 if (pppoe_length > length) { 134 ND_PRINT(" [len %u > %u!]", pppoe_length, length); 135 pppoe_length = length; 136 } 137 if (pppoe_sessionid) { 138 ND_PRINT(" [ses 0x%x]", pppoe_sessionid); 139 } 140 141 if (pppoe_code) { 142 /* PPP session packets don't contain tags */ 143 u_short tag_type = 0xffff, tag_len; 144 const u_char *p = pppoe_payload; 145 146 /* 147 * loop invariant: 148 * p points to current tag, 149 * tag_type is previous tag or 0xffff for first iteration 150 */ 151 while (tag_type && p < pppoe_payload + pppoe_length) { 152 tag_type = GET_BE_U_2(p); 153 tag_len = GET_BE_U_2(p + 2); 154 p += 4; 155 /* p points to tag_value */ 156 157 if (tag_len) { 158 unsigned ascii_count = 0, garbage_count = 0; 159 const u_char *v; 160 char tag_str[MAXTAGPRINT]; 161 unsigned tag_str_len = 0; 162 163 /* TODO print UTF-8 decoded text */ 164 ND_TCHECK_LEN(p, tag_len); 165 for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++) 166 if (ND_ASCII_ISPRINT(GET_U_1(v))) { 167 tag_str[tag_str_len++] = GET_U_1(v); 168 ascii_count++; 169 } else { 170 tag_str[tag_str_len++] = '.'; 171 garbage_count++; 172 } 173 tag_str[tag_str_len] = 0; 174 175 if (ascii_count > garbage_count) { 176 ND_PRINT(" [%s \"%*.*s\"]", 177 tok2str(pppoetag2str, "TAG-0x%x", tag_type), 178 (int)tag_str_len, 179 (int)tag_str_len, 180 tag_str); 181 } else { 182 /* Print hex, not fast to abuse printf but this doesn't get used much */ 183 ND_PRINT(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type)); 184 for (v=p; v<p+tag_len; v++) { 185 ND_PRINT("%02X", GET_U_1(v)); 186 } 187 ND_PRINT("]"); 188 } 189 190 191 } else 192 ND_PRINT(" [%s]", tok2str(pppoetag2str, 193 "TAG-0x%x", tag_type)); 194 195 p += tag_len; 196 /* p points to next tag */ 197 } 198 return PPPOE_HDRLEN; 199 } else { 200 /* PPPoE data */ 201 ND_PRINT(" "); 202 return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length)); 203 } 204 /* NOTREACHED */ 205 206 invalid: 207 nd_print_invalid(ndo); 208 return 0; 209 } 210