xref: /minix3/external/bsd/tcpdump/dist/print-pppoe.c (revision b636d99d91c3d54204248f643c14627405d4afd1)
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 1.5 2014/11/20 03:05:03 christos Exp $");
27 #endif
28 
29 #define NETDISSECT_REWORKED
30 #ifdef HAVE_CONFIG_H
31 #include "config.h"
32 #endif
33 
34 #include <tcpdump-stdinc.h>
35 
36 #include "interface.h"
37 #include "extract.h"			/* must come after interface.h */
38 
39 /* Codes */
40 enum {
41 	PPPOE_PADI = 0x09,
42 	PPPOE_PADO = 0x07,
43 	PPPOE_PADR = 0x19,
44 	PPPOE_PADS = 0x65,
45 	PPPOE_PADT = 0xa7
46 };
47 
48 static const struct tok pppoecode2str[] = {
49 	{ PPPOE_PADI, "PADI" },
50 	{ PPPOE_PADO, "PADO" },
51 	{ PPPOE_PADR, "PADR" },
52 	{ PPPOE_PADS, "PADS" },
53 	{ PPPOE_PADT, "PADT" },
54 	{ 0, "" }, /* PPP Data */
55 	{ 0, NULL }
56 };
57 
58 /* Tags */
59 enum {
60 	PPPOE_EOL = 0,
61 	PPPOE_SERVICE_NAME = 0x0101,
62 	PPPOE_AC_NAME = 0x0102,
63 	PPPOE_HOST_UNIQ = 0x0103,
64 	PPPOE_AC_COOKIE = 0x0104,
65 	PPPOE_VENDOR = 0x0105,
66 	PPPOE_RELAY_SID = 0x0110,
67 	PPPOE_MAX_PAYLOAD = 0x0120,
68 	PPPOE_SERVICE_NAME_ERROR = 0x0201,
69 	PPPOE_AC_SYSTEM_ERROR = 0x0202,
70 	PPPOE_GENERIC_ERROR = 0x0203
71 };
72 
73 static const struct tok pppoetag2str[] = {
74 	{ PPPOE_EOL, "EOL" },
75 	{ PPPOE_SERVICE_NAME, "Service-Name" },
76 	{ PPPOE_AC_NAME, "AC-Name" },
77 	{ PPPOE_HOST_UNIQ, "Host-Uniq" },
78 	{ PPPOE_AC_COOKIE, "AC-Cookie" },
79 	{ PPPOE_VENDOR, "Vendor-Specific" },
80 	{ PPPOE_RELAY_SID, "Relay-Session-ID" },
81 	{ PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
82 	{ PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
83 	{ PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
84 	{ PPPOE_GENERIC_ERROR, "Generic-Error" },
85 	{ 0, NULL }
86 };
87 
88 #define PPPOE_HDRLEN 6
89 #define MAXTAGPRINT 80
90 
91 u_int
pppoe_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,register const u_char * p)92 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, register const u_char *p)
93 {
94 	return (pppoe_print(ndo, p, h->len));
95 }
96 
97 u_int
pppoe_print(netdissect_options * ndo,register const u_char * bp,u_int length)98 pppoe_print(netdissect_options *ndo, register const u_char *bp, u_int length)
99 {
100 	uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
101 	u_int pppoe_length;
102 	const u_char *pppoe_packet, *pppoe_payload;
103 
104 	if (length < PPPOE_HDRLEN) {
105 		ND_PRINT((ndo, "truncated-pppoe %u", length));
106 		return (length);
107 	}
108 	length -= PPPOE_HDRLEN;
109 	pppoe_packet = bp;
110 	ND_TCHECK2(*pppoe_packet, PPPOE_HDRLEN);
111 	pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
112 	pppoe_type  = (pppoe_packet[0] & 0x0F);
113 	pppoe_code = pppoe_packet[1];
114 	pppoe_sessionid = EXTRACT_16BITS(pppoe_packet + 2);
115 	pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
116 	pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
117 
118 	if (pppoe_ver != 1) {
119 		ND_PRINT((ndo, " [ver %d]",pppoe_ver));
120 	}
121 	if (pppoe_type != 1) {
122 		ND_PRINT((ndo, " [type %d]",pppoe_type));
123 	}
124 
125 	ND_PRINT((ndo, "PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code)));
126 	if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
127 		ND_PRINT((ndo, " [len %u!]",pppoe_length));
128 	}
129 	if (pppoe_length > length) {
130 		ND_PRINT((ndo, " [len %u > %u!]", pppoe_length, length));
131 		pppoe_length = length;
132 	}
133 	if (pppoe_sessionid) {
134 		ND_PRINT((ndo, " [ses 0x%x]", pppoe_sessionid));
135 	}
136 
137 	if (pppoe_code) {
138 		/* PPP session packets don't contain tags */
139 		u_short tag_type = 0xffff, tag_len;
140 		const u_char *p = pppoe_payload;
141 
142 		/*
143 		 * loop invariant:
144 		 * p points to current tag,
145 		 * tag_type is previous tag or 0xffff for first iteration
146 		 */
147 		while (tag_type && p < pppoe_payload + pppoe_length) {
148 			ND_TCHECK2(*p, 4);
149 			tag_type = EXTRACT_16BITS(p);
150 			tag_len = EXTRACT_16BITS(p + 2);
151 			p += 4;
152 			/* p points to tag_value */
153 
154 			if (tag_len) {
155 				unsigned isascii = 0, isgarbage = 0;
156 				const u_char *v;
157 				char tag_str[MAXTAGPRINT];
158 				unsigned tag_str_len = 0;
159 
160 				/* TODO print UTF-8 decoded text */
161 				ND_TCHECK2(*p, tag_len);
162 				for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
163 					if (*v >= 32 && *v < 127) {
164 						tag_str[tag_str_len++] = *v;
165 						isascii++;
166 					} else {
167 						tag_str[tag_str_len++] = '.';
168 						isgarbage++;
169 					}
170 				tag_str[tag_str_len] = 0;
171 
172 				if (isascii > isgarbage) {
173 					ND_PRINT((ndo, " [%s \"%*.*s\"]",
174 					       tok2str(pppoetag2str, "TAG-0x%x", tag_type),
175 					       (int)tag_str_len,
176 					       (int)tag_str_len,
177 					       tag_str));
178 				} else {
179 					/* Print hex, not fast to abuse printf but this doesn't get used much */
180 					ND_PRINT((ndo, " [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type)));
181 					for (v=p; v<p+tag_len; v++) {
182 						ND_PRINT((ndo, "%02X", *v));
183 					}
184 					ND_PRINT((ndo, "]"));
185 				}
186 
187 
188 			} else
189 				ND_PRINT((ndo, " [%s]", tok2str(pppoetag2str,
190 				    "TAG-0x%x", tag_type)));
191 
192 			p += tag_len;
193 			/* p points to next tag */
194 		}
195 		return (0);
196 	} else {
197 		/* PPPoE data */
198 		ND_PRINT((ndo, " "));
199 		return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
200 	}
201 
202 trunc:
203 	ND_PRINT((ndo, "[|pppoe]"));
204 	return (PPPOE_HDRLEN);
205 }
206