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