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