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