xref: /freebsd/contrib/tcpdump/print-pppoe.c (revision 4c8945a06b01a5c8122cdeb402af36bb46a06acc)
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 #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 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_SERVICE_NAME_ERROR = 0x0201,
74 	PPPOE_AC_SYSTEM_ERROR = 0x0202,
75 	PPPOE_GENERIC_ERROR = 0x0203
76 };
77 
78 static struct tok pppoetag2str[] = {
79 	{ PPPOE_EOL, "EOL" },
80 	{ PPPOE_SERVICE_NAME, "Service-Name" },
81 	{ PPPOE_AC_NAME, "AC-Name" },
82 	{ PPPOE_HOST_UNIQ, "Host-Uniq" },
83 	{ PPPOE_AC_COOKIE, "AC-Cookie" },
84 	{ PPPOE_VENDOR, "Vendor-Specific" },
85 	{ PPPOE_RELAY_SID, "Relay-Session-ID" },
86 	{ PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
87 	{ PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
88 	{ PPPOE_GENERIC_ERROR, "Generic-Error" },
89 	{ 0, NULL }
90 };
91 
92 #define PPPOE_HDRLEN 6
93 #define MAXTAGPRINT 80
94 
95 u_int
96 pppoe_if_print(const struct pcap_pkthdr *h, register const u_char *p)
97 {
98 	return (pppoe_print(p, h->len));
99 }
100 
101 u_int
102 pppoe_print(register const u_char *bp, u_int length)
103 {
104 	u_int16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
105 	u_int pppoe_length;
106 	const u_char *pppoe_packet, *pppoe_payload;
107 
108 	if (length < PPPOE_HDRLEN) {
109 		(void)printf("truncated-pppoe %u", length);
110 		return (length);
111 	}
112 	length -= PPPOE_HDRLEN;
113 	pppoe_packet = bp;
114 	TCHECK2(*pppoe_packet, PPPOE_HDRLEN);
115 	pppoe_ver  = (pppoe_packet[0] & 0xF0) >> 4;
116 	pppoe_type  = (pppoe_packet[0] & 0x0F);
117 	pppoe_code = pppoe_packet[1];
118 	pppoe_sessionid = EXTRACT_16BITS(pppoe_packet + 2);
119 	pppoe_length    = EXTRACT_16BITS(pppoe_packet + 4);
120 	pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
121 
122 	if (pppoe_ver != 1) {
123 		printf(" [ver %d]",pppoe_ver);
124 	}
125 	if (pppoe_type != 1) {
126 		printf(" [type %d]",pppoe_type);
127 	}
128 
129 	printf("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
130 	if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
131 		printf(" [len %u!]",pppoe_length);
132 	}
133 	if (pppoe_length > length) {
134 		printf(" [len %u > %u!]", pppoe_length, length);
135 		pppoe_length = length;
136 	}
137 	if (pppoe_sessionid) {
138 		printf(" [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 			TCHECK2(*p, 4);
153 			tag_type = EXTRACT_16BITS(p);
154 			tag_len = EXTRACT_16BITS(p + 2);
155 			p += 4;
156 			/* p points to tag_value */
157 
158 			if (tag_len) {
159 				unsigned isascii = 0, isgarbage = 0;
160 				const u_char *v = p;
161 				char tag_str[MAXTAGPRINT];
162 				unsigned tag_str_len = 0;
163 
164 				/* TODO print UTF-8 decoded text */
165 				TCHECK2(*p, tag_len);
166 				for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
167 					if (*v >= 32 && *v < 127) {
168 						tag_str[tag_str_len++] = *v;
169 						isascii++;
170 					} else {
171 						tag_str[tag_str_len++] = '.';
172 						isgarbage++;
173 					}
174 				tag_str[tag_str_len] = 0;
175 
176 				if (isascii > isgarbage) {
177 					printf(" [%s \"%*.*s\"]",
178 					       tok2str(pppoetag2str, "TAG-0x%x", tag_type),
179 					       (int)tag_str_len,
180 					       (int)tag_str_len,
181 					       tag_str);
182 				} else {
183 					/* Print hex, not fast to abuse printf but this doesn't get used much */
184 					printf(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
185 					for (v=p; v<p+tag_len; v++) {
186 						printf("%02X", *v);
187 					}
188 					printf("]");
189 				}
190 
191 
192 			} else
193 				printf(" [%s]", tok2str(pppoetag2str,
194 				    "TAG-0x%x", tag_type));
195 
196 			p += tag_len;
197 			/* p points to next tag */
198 		}
199 		return (0);
200 	} else {
201 		/* PPPoE data */
202 		printf(" ");
203 		return (PPPOE_HDRLEN + ppp_print(pppoe_payload, pppoe_length));
204 	}
205 
206 trunc:
207 	printf("[|pppoe]");
208 	return (PPPOE_HDRLEN);
209 }
210