xref: /dragonfly/contrib/tcpdump/print-pppoe.c (revision ed775ee7)
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 /* \summary: PPP-over-Ethernet (PPPoE) printer */
25 
26 #ifdef HAVE_CONFIG_H
27 #include <config.h>
28 #endif
29 
30 #include "netdissect-stdinc.h"
31 
32 #include "netdissect-ctype.h"
33 
34 #define ND_LONGJMP_FROM_TCHECK
35 #include "netdissect.h"
36 #include "extract.h"
37 
38 /* Codes */
39 enum {
40 	PPPOE_PADI = 0x09,
41 	PPPOE_PADO = 0x07,
42 	PPPOE_PADR = 0x19,
43 	PPPOE_PADS = 0x65,
44 	PPPOE_PADT = 0xa7
45 };
46 
47 static const struct tok pppoecode2str[] = {
48 	{ PPPOE_PADI, "PADI" },
49 	{ PPPOE_PADO, "PADO" },
50 	{ PPPOE_PADR, "PADR" },
51 	{ PPPOE_PADS, "PADS" },
52 	{ PPPOE_PADT, "PADT" },
53 	{ 0, "" }, /* PPP Data */
54 	{ 0, NULL }
55 };
56 
57 /* Tags */
58 enum {
59 	PPPOE_EOL = 0,
60 	PPPOE_SERVICE_NAME = 0x0101,
61 	PPPOE_AC_NAME = 0x0102,
62 	PPPOE_HOST_UNIQ = 0x0103,
63 	PPPOE_AC_COOKIE = 0x0104,
64 	PPPOE_VENDOR = 0x0105,
65 	PPPOE_RELAY_SID = 0x0110,
66 	PPPOE_MAX_PAYLOAD = 0x0120,
67 	PPPOE_SERVICE_NAME_ERROR = 0x0201,
68 	PPPOE_AC_SYSTEM_ERROR = 0x0202,
69 	PPPOE_GENERIC_ERROR = 0x0203
70 };
71 
72 static const struct tok pppoetag2str[] = {
73 	{ PPPOE_EOL, "EOL" },
74 	{ PPPOE_SERVICE_NAME, "Service-Name" },
75 	{ PPPOE_AC_NAME, "AC-Name" },
76 	{ PPPOE_HOST_UNIQ, "Host-Uniq" },
77 	{ PPPOE_AC_COOKIE, "AC-Cookie" },
78 	{ PPPOE_VENDOR, "Vendor-Specific" },
79 	{ PPPOE_RELAY_SID, "Relay-Session-ID" },
80 	{ PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
81 	{ PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
82 	{ PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
83 	{ PPPOE_GENERIC_ERROR, "Generic-Error" },
84 	{ 0, NULL }
85 };
86 
87 #define PPPOE_HDRLEN 6
88 #define MAXTAGPRINT 80
89 
90 void
pppoe_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)91 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
92 {
93 	ndo->ndo_protocol = "pppoe";
94 	ndo->ndo_ll_hdr_len += pppoe_print(ndo, p, h->len);
95 }
96 
97 u_int
pppoe_print(netdissect_options * ndo,const u_char * bp,u_int length)98 pppoe_print(netdissect_options *ndo, 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 	ndo->ndo_protocol = "pppoe";
105 	if (length < PPPOE_HDRLEN) {
106 		ND_PRINT(" (length %u < %u)", length, PPPOE_HDRLEN);
107 		goto invalid;
108 	}
109 	length -= PPPOE_HDRLEN;
110 	pppoe_packet = bp;
111 	ND_TCHECK_LEN(pppoe_packet, PPPOE_HDRLEN);
112 	pppoe_ver  = (GET_U_1(pppoe_packet) & 0xF0) >> 4;
113 	pppoe_type  = (GET_U_1(pppoe_packet) & 0x0F);
114 	pppoe_code = GET_U_1(pppoe_packet + 1);
115 	pppoe_sessionid = GET_BE_U_2(pppoe_packet + 2);
116 	pppoe_length    = GET_BE_U_2(pppoe_packet + 4);
117 	pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
118 
119 	if (pppoe_ver != 1) {
120 		ND_PRINT(" [ver %u]",pppoe_ver);
121 	}
122 	if (pppoe_type != 1) {
123 		ND_PRINT(" [type %u]",pppoe_type);
124 	}
125 
126 	ND_PRINT("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
127 	if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
128 		ND_PRINT(" [len %u!]",pppoe_length);
129 	}
130 	if (pppoe_length > length) {
131 		ND_PRINT(" [len %u > %u!]", pppoe_length, length);
132 		pppoe_length = length;
133 	}
134 	if (pppoe_sessionid) {
135 		ND_PRINT(" [ses 0x%x]", pppoe_sessionid);
136 	}
137 
138 	if (pppoe_code) {
139 		/* PPP session packets don't contain tags */
140 		u_short tag_type = 0xffff, tag_len;
141 		const u_char *p = pppoe_payload;
142 
143 		/*
144 		 * loop invariant:
145 		 * p points to current tag,
146 		 * tag_type is previous tag or 0xffff for first iteration
147 		 */
148 		while (tag_type && p < pppoe_payload + pppoe_length) {
149 			tag_type = GET_BE_U_2(p);
150 			tag_len = GET_BE_U_2(p + 2);
151 			p += 4;
152 			/* p points to tag_value */
153 
154 			if (tag_len) {
155 				unsigned ascii_count = 0, garbage_count = 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_TCHECK_LEN(p, tag_len);
162 				for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
163 					if (ND_ASCII_ISPRINT(GET_U_1(v))) {
164 						tag_str[tag_str_len++] = GET_U_1(v);
165 						ascii_count++;
166 					} else {
167 						tag_str[tag_str_len++] = '.';
168 						garbage_count++;
169 					}
170 				tag_str[tag_str_len] = 0;
171 
172 				if (ascii_count > garbage_count) {
173 					ND_PRINT(" [%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(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
181 					for (v=p; v<p+tag_len; v++) {
182 						ND_PRINT("%02X", GET_U_1(v));
183 					}
184 					ND_PRINT("]");
185 				}
186 
187 
188 			} else
189 				ND_PRINT(" [%s]", tok2str(pppoetag2str,
190 				    "TAG-0x%x", tag_type));
191 
192 			p += tag_len;
193 			/* p points to next tag */
194 		}
195 		return PPPOE_HDRLEN;
196 	} else {
197 		/* PPPoE data */
198 		ND_PRINT(" ");
199 		return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
200 	}
201 	/* NOTREACHED */
202 
203 invalid:
204 	nd_print_invalid(ndo);
205 	return 0;
206 }
207