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      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 (at) mit.edu>
     22  */
     23 
     24 #ifndef lint
     25 static const char rcsid[] _U_ =
     26 "@(#) $Header: /tcpdump/master/tcpdump/print-pppoe.c,v 1.31 2005-04-26 19:48:38 guy 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 const 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_MAX_PAYLOAD = 0x0120,
     74 	PPPOE_SERVICE_NAME_ERROR = 0x0201,
     75 	PPPOE_AC_SYSTEM_ERROR = 0x0202,
     76 	PPPOE_GENERIC_ERROR = 0x0203
     77 };
     78 
     79 static const struct tok pppoetag2str[] = {
     80 	{ PPPOE_EOL, "EOL" },
     81 	{ PPPOE_SERVICE_NAME, "Service-Name" },
     82 	{ PPPOE_AC_NAME, "AC-Name" },
     83 	{ PPPOE_HOST_UNIQ, "Host-Uniq" },
     84 	{ PPPOE_AC_COOKIE, "AC-Cookie" },
     85 	{ PPPOE_VENDOR, "Vendor-Specific" },
     86 	{ PPPOE_RELAY_SID, "Relay-Session-ID" },
     87 	{ PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
     88 	{ PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
     89 	{ PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
     90 	{ PPPOE_GENERIC_ERROR, "Generic-Error" },
     91 	{ 0, NULL }
     92 };
     93 
     94 #define PPPOE_HDRLEN 6
     95 #define MAXTAGPRINT 80
     96 
     97 u_int
     98 pppoe_if_print(const struct pcap_pkthdr *h, register const u_char *p)
     99 {
    100 	return (pppoe_print(p, h->len));
    101 }
    102 
    103 u_int
    104 pppoe_print(register const u_char *bp, u_int length)
    105 {
    106 	u_int16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
    107 	u_int pppoe_length;
    108 	const u_char *pppoe_packet, *pppoe_payload;
    109 
    110 	if (length < PPPOE_HDRLEN) {
    111 		(void)printf("truncated-pppoe %u", length);
    112 		return (length);
    113 	}
    114 	length -= PPPOE_HDRLEN;
    115 	pppoe_packet = bp;
    116 	TCHECK2(*pppoe_packet, PPPOE_HDRLEN);
    117 	pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
    118 	pppoe_type  = (pppoe_packet[0] & 0x0F);
    119 	pppoe_code = pppoe_packet[1];
    120 	pppoe_sessionid = EXTRACT_16BITS(pppoe_packet + 2);
    121 	pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
    122 	pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
    123 
    124 	if (pppoe_ver != 1) {
    125 		printf(" [ver %d]",pppoe_ver);
    126 	}
    127 	if (pppoe_type != 1) {
    128 		printf(" [type %d]",pppoe_type);
    129 	}
    130 
    131 	printf("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
    132 	if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
    133 		printf(" [len %u!]",pppoe_length);
    134 	}
    135 	if (pppoe_length > length) {
    136 		printf(" [len %u > %u!]", pppoe_length, length);
    137 		pppoe_length = length;
    138 	}
    139 	if (pppoe_sessionid) {
    140 		printf(" [ses 0x%x]", pppoe_sessionid);
    141 	}
    142 
    143 	if (pppoe_code) {
    144 		/* PPP session packets don't contain tags */
    145 		u_short tag_type = 0xffff, tag_len;
    146 		const u_char *p = pppoe_payload;
    147 
    148 		/*
    149 		 * loop invariant:
    150 		 * p points to current tag,
    151 		 * tag_type is previous tag or 0xffff for first iteration
    152 		 */
    153 		while (tag_type && p < pppoe_payload + pppoe_length) {
    154 			TCHECK2(*p, 4);
    155 			tag_type = EXTRACT_16BITS(p);
    156 			tag_len = EXTRACT_16BITS(p + 2);
    157 			p += 4;
    158 			/* p points to tag_value */
    159 
    160 			if (tag_len) {
    161 				unsigned isascii = 0, isgarbage = 0;
    162 				const u_char *v;
    163 				char tag_str[MAXTAGPRINT];
    164 				unsigned tag_str_len = 0;
    165 
    166 				/* TODO print UTF-8 decoded text */
    167 				TCHECK2(*p, tag_len);
    168 				for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
    169 					if (*v >= 32 && *v < 127) {
    170 						tag_str[tag_str_len++] = *v;
    171 						isascii++;
    172 					} else {
    173 						tag_str[tag_str_len++] = '.';
    174 						isgarbage++;
    175 					}
    176 				tag_str[tag_str_len] = 0;
    177 
    178 				if (isascii > isgarbage) {
    179 					printf(" [%s \"%*.*s\"]",
    180 					       tok2str(pppoetag2str, "TAG-0x%x", tag_type),
    181 					       (int)tag_str_len,
    182 					       (int)tag_str_len,
    183 					       tag_str);
    184 				} else {
    185 					/* Print hex, not fast to abuse printf but this doesn't get used much */
    186 					printf(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
    187 					for (v=p; v<p+tag_len; v++) {
    188 						printf("%02X", *v);
    189 					}
    190 					printf("]");
    191 				}
    192 
    193 
    194 			} else
    195 				printf(" [%s]", tok2str(pppoetag2str,
    196 				    "TAG-0x%x", tag_type));
    197 
    198 			p += tag_len;
    199 			/* p points to next tag */
    200 		}
    201 		return (0);
    202 	} else {
    203 		/* PPPoE data */
    204 		printf(" ");
    205 		return (PPPOE_HDRLEN + ppp_print(pppoe_payload, pppoe_length));
    206 	}
    207 
    208 trunc:
    209 	printf("[|pppoe]");
    210 	return (PPPOE_HDRLEN);
    211 }
    212