1 /*
2 * Copyright (c) 1990, 1991, 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
22 /* \summary: Cisco HDLC printer */
23
24 #include <config.h>
25
26 #include "netdissect-stdinc.h"
27
28 #include "netdissect.h"
29 #include "addrtoname.h"
30 #include "ethertype.h"
31 #include "extract.h"
32 #include "chdlc.h"
33 #include "nlpid.h"
34
35 static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int);
36
37 static const struct tok chdlc_cast_values[] = {
38 { CHDLC_UNICAST, "unicast" },
39 { CHDLC_BCAST, "bcast" },
40 { 0, NULL}
41 };
42
43
44 /* Standard CHDLC printer */
45 void
chdlc_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)46 chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
47 {
48 ndo->ndo_protocol = "chdlc";
49 ndo->ndo_ll_hdr_len += chdlc_print(ndo, p, h->len);
50 }
51
52 u_int
chdlc_print(netdissect_options * ndo,const u_char * p,u_int length)53 chdlc_print(netdissect_options *ndo, const u_char *p, u_int length)
54 {
55 u_int proto;
56 const u_char *bp = p;
57
58 ndo->ndo_protocol = "chdlc";
59 if (length < CHDLC_HDRLEN)
60 goto trunc;
61 proto = GET_BE_U_2(p + 2);
62 if (ndo->ndo_eflag) {
63 ND_PRINT("%s, ethertype %s (0x%04x), length %u: ",
64 tok2str(chdlc_cast_values, "0x%02x", GET_U_1(p)),
65 tok2str(ethertype_values, "Unknown", proto),
66 proto,
67 length);
68 }
69
70 length -= CHDLC_HDRLEN;
71 p += CHDLC_HDRLEN;
72
73 switch (proto) {
74 case ETHERTYPE_IP:
75 ip_print(ndo, p, length);
76 break;
77 case ETHERTYPE_IPV6:
78 ip6_print(ndo, p, length);
79 break;
80 case CHDLC_TYPE_SLARP:
81 chdlc_slarp_print(ndo, p, length);
82 break;
83 case ETHERTYPE_MPLS:
84 case ETHERTYPE_MPLS_MULTI:
85 mpls_print(ndo, p, length);
86 break;
87 case ETHERTYPE_ISO:
88 /* is the fudge byte set ? lets verify by spotting ISO headers */
89 if (length < 2)
90 goto trunc;
91 if (GET_U_1(p + 1) == NLPID_CLNP ||
92 GET_U_1(p + 1) == NLPID_ESIS ||
93 GET_U_1(p + 1) == NLPID_ISIS)
94 isoclns_print(ndo, p + 1, length - 1);
95 else
96 isoclns_print(ndo, p, length);
97 break;
98 default:
99 if (!ndo->ndo_eflag)
100 ND_PRINT("unknown CHDLC protocol (0x%04x)", proto);
101 break;
102 }
103
104 return (CHDLC_HDRLEN);
105
106 trunc:
107 nd_print_trunc(ndo);
108 return (ND_BYTES_AVAILABLE_AFTER(bp));
109 }
110
111 /*
112 * The fixed-length portion of a SLARP packet.
113 */
114 struct cisco_slarp {
115 nd_uint32_t code;
116 #define SLARP_REQUEST 0
117 #define SLARP_REPLY 1
118 #define SLARP_KEEPALIVE 2
119 union {
120 struct {
121 uint8_t addr[4];
122 uint8_t mask[4];
123 } addr;
124 struct {
125 nd_uint32_t myseq;
126 nd_uint32_t yourseq;
127 nd_uint16_t rel;
128 } keep;
129 } un;
130 };
131
132 #define SLARP_MIN_LEN 14
133 #define SLARP_MAX_LEN 18
134
135 static void
chdlc_slarp_print(netdissect_options * ndo,const u_char * cp,u_int length)136 chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length)
137 {
138 const struct cisco_slarp *slarp;
139 u_int sec,min,hrs,days;
140
141 ndo->ndo_protocol = "chdlc_slarp";
142 ND_PRINT("SLARP (length: %u), ",length);
143 if (length < SLARP_MIN_LEN)
144 goto trunc;
145
146 slarp = (const struct cisco_slarp *)cp;
147 ND_TCHECK_LEN(slarp, SLARP_MIN_LEN);
148 switch (GET_BE_U_4(slarp->code)) {
149 case SLARP_REQUEST:
150 ND_PRINT("request");
151 /*
152 * At least according to William "Chops" Westfield's
153 * message in
154 *
155 * https://web.archive.org/web/20190725151313/www.nethelp.no/net/cisco-hdlc.txt
156 *
157 * the address and mask aren't used in requests -
158 * they're just zero.
159 */
160 break;
161 case SLARP_REPLY:
162 ND_PRINT("reply %s/%s",
163 GET_IPADDR_STRING(slarp->un.addr.addr),
164 GET_IPADDR_STRING(slarp->un.addr.mask));
165 break;
166 case SLARP_KEEPALIVE:
167 ND_PRINT("keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x",
168 GET_BE_U_4(slarp->un.keep.myseq),
169 GET_BE_U_4(slarp->un.keep.yourseq),
170 GET_BE_U_2(slarp->un.keep.rel));
171
172 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */
173 cp += SLARP_MIN_LEN;
174 sec = GET_BE_U_4(cp) / 1000;
175 min = sec / 60; sec -= min * 60;
176 hrs = min / 60; min -= hrs * 60;
177 days = hrs / 24; hrs -= days * 24;
178 ND_PRINT(", link uptime=%ud%uh%um%us",days,hrs,min,sec);
179 }
180 break;
181 default:
182 ND_PRINT("0x%02x unknown", GET_BE_U_4(slarp->code));
183 if (ndo->ndo_vflag <= 1)
184 print_unknown_data(ndo,cp+4,"\n\t",length-4);
185 break;
186 }
187
188 if (SLARP_MAX_LEN < length && ndo->ndo_vflag)
189 ND_PRINT(", (trailing junk: %u bytes)", length - SLARP_MAX_LEN);
190 if (ndo->ndo_vflag > 1)
191 print_unknown_data(ndo,cp+4,"\n\t",length-4);
192 return;
193
194 trunc:
195 nd_print_trunc(ndo);
196 }
197