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 #include <config.h>
27
28 #include "netdissect-stdinc.h"
29
30 #include "netdissect-ctype.h"
31
32 #define ND_LONGJMP_FROM_TCHECK
33 #include "netdissect.h"
34 #include "extract.h"
35
36 /* Codes */
37 enum {
38 PPPOE_PADI = 0x09,
39 PPPOE_PADO = 0x07,
40 PPPOE_PADR = 0x19,
41 PPPOE_PADS = 0x65,
42 PPPOE_PADT = 0xa7
43 };
44
45 static const struct tok pppoecode2str[] = {
46 { PPPOE_PADI, "PADI" },
47 { PPPOE_PADO, "PADO" },
48 { PPPOE_PADR, "PADR" },
49 { PPPOE_PADS, "PADS" },
50 { PPPOE_PADT, "PADT" },
51 { 0, "" }, /* PPP Data */
52 { 0, NULL }
53 };
54
55 /* Tags */
56 enum {
57 PPPOE_EOL = 0,
58 PPPOE_SERVICE_NAME = 0x0101,
59 PPPOE_AC_NAME = 0x0102,
60 PPPOE_HOST_UNIQ = 0x0103,
61 PPPOE_AC_COOKIE = 0x0104,
62 PPPOE_VENDOR = 0x0105,
63 PPPOE_RELAY_SID = 0x0110,
64 PPPOE_MAX_PAYLOAD = 0x0120,
65 PPPOE_SERVICE_NAME_ERROR = 0x0201,
66 PPPOE_AC_SYSTEM_ERROR = 0x0202,
67 PPPOE_GENERIC_ERROR = 0x0203
68 };
69
70 static const struct tok pppoetag2str[] = {
71 { PPPOE_EOL, "EOL" },
72 { PPPOE_SERVICE_NAME, "Service-Name" },
73 { PPPOE_AC_NAME, "AC-Name" },
74 { PPPOE_HOST_UNIQ, "Host-Uniq" },
75 { PPPOE_AC_COOKIE, "AC-Cookie" },
76 { PPPOE_VENDOR, "Vendor-Specific" },
77 { PPPOE_RELAY_SID, "Relay-Session-ID" },
78 { PPPOE_MAX_PAYLOAD, "PPP-Max-Payload" },
79 { PPPOE_SERVICE_NAME_ERROR, "Service-Name-Error" },
80 { PPPOE_AC_SYSTEM_ERROR, "AC-System-Error" },
81 { PPPOE_GENERIC_ERROR, "Generic-Error" },
82 { 0, NULL }
83 };
84
85 #define PPPOE_HDRLEN 6
86 #define MAXTAGPRINT 80
87
88 void
pppoe_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)89 pppoe_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
90 {
91 ndo->ndo_protocol = "pppoe";
92 ndo->ndo_ll_hdr_len += pppoe_print(ndo, p, h->len);
93 }
94
95 u_int
pppoe_print(netdissect_options * ndo,const u_char * bp,u_int length)96 pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length)
97 {
98 uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
99 u_int pppoe_length;
100 const u_char *pppoe_packet, *pppoe_payload;
101
102 ndo->ndo_protocol = "pppoe";
103 if (length < PPPOE_HDRLEN) {
104 ND_PRINT(" (length %u < %u)", length, PPPOE_HDRLEN);
105 goto invalid;
106 }
107 length -= PPPOE_HDRLEN;
108 pppoe_packet = bp;
109 ND_TCHECK_LEN(pppoe_packet, PPPOE_HDRLEN);
110 pppoe_ver = (GET_U_1(pppoe_packet) & 0xF0) >> 4;
111 pppoe_type = (GET_U_1(pppoe_packet) & 0x0F);
112 pppoe_code = GET_U_1(pppoe_packet + 1);
113 pppoe_sessionid = GET_BE_U_2(pppoe_packet + 2);
114 pppoe_length = GET_BE_U_2(pppoe_packet + 4);
115 pppoe_payload = pppoe_packet + PPPOE_HDRLEN;
116
117 if (pppoe_ver != 1) {
118 ND_PRINT(" [ver %u]",pppoe_ver);
119 }
120 if (pppoe_type != 1) {
121 ND_PRINT(" [type %u]",pppoe_type);
122 }
123
124 ND_PRINT("PPPoE %s", tok2str(pppoecode2str, "PAD-%x", pppoe_code));
125 if (pppoe_code == PPPOE_PADI && pppoe_length > 1484 - PPPOE_HDRLEN) {
126 ND_PRINT(" [len %u!]",pppoe_length);
127 }
128 if (pppoe_length > length) {
129 ND_PRINT(" [len %u > %u!]", pppoe_length, length);
130 pppoe_length = length;
131 }
132 if (pppoe_sessionid) {
133 ND_PRINT(" [ses 0x%x]", pppoe_sessionid);
134 }
135
136 if (pppoe_code) {
137 /* PPP session packets don't contain tags */
138 u_short tag_type = 0xffff, tag_len;
139 const u_char *p = pppoe_payload;
140
141 /*
142 * loop invariant:
143 * p points to current tag,
144 * tag_type is previous tag or 0xffff for first iteration
145 */
146 while (tag_type && p < pppoe_payload + pppoe_length) {
147 tag_type = GET_BE_U_2(p);
148 tag_len = GET_BE_U_2(p + 2);
149 p += 4;
150 /* p points to tag_value */
151
152 if (tag_len) {
153 unsigned ascii_count = 0, garbage_count = 0;
154 const u_char *v;
155 char tag_str[MAXTAGPRINT];
156 unsigned tag_str_len = 0;
157
158 /* TODO print UTF-8 decoded text */
159 ND_TCHECK_LEN(p, tag_len);
160 for (v = p; v < p + tag_len && tag_str_len < MAXTAGPRINT-1; v++)
161 if (ND_ASCII_ISPRINT(GET_U_1(v))) {
162 tag_str[tag_str_len++] = GET_U_1(v);
163 ascii_count++;
164 } else {
165 tag_str[tag_str_len++] = '.';
166 garbage_count++;
167 }
168 tag_str[tag_str_len] = 0;
169
170 if (ascii_count > garbage_count) {
171 ND_PRINT(" [%s \"%*.*s\"]",
172 tok2str(pppoetag2str, "TAG-0x%x", tag_type),
173 (int)tag_str_len,
174 (int)tag_str_len,
175 tag_str);
176 } else {
177 /* Print hex, not fast to abuse printf but this doesn't get used much */
178 ND_PRINT(" [%s 0x", tok2str(pppoetag2str, "TAG-0x%x", tag_type));
179 for (v=p; v<p+tag_len; v++) {
180 ND_PRINT("%02X", GET_U_1(v));
181 }
182 ND_PRINT("]");
183 }
184
185
186 } else
187 ND_PRINT(" [%s]", tok2str(pppoetag2str,
188 "TAG-0x%x", tag_type));
189
190 p += tag_len;
191 /* p points to next tag */
192 }
193 return PPPOE_HDRLEN;
194 } else {
195 /* PPPoE data */
196 ND_PRINT(" ");
197 return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
198 }
199 /* NOTREACHED */
200
201 invalid:
202 nd_print_invalid(ndo);
203 return 0;
204 }
205