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1 /*
2  * Copyright (c) 1998-2007 The TCPDUMP project
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that: (1) source code
6  * distributions retain the above copyright notice and this paragraph
7  * in its entirety, and (2) distributions including binary code include
8  * the above copyright notice and this paragraph in its entirety in
9  * the documentation or other materials provided with the distribution.
10  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
11  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
12  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
13  * FOR A PARTICULAR PURPOSE.
14  *
15  * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
16  */
17 
18 /* \summary: Dynamic Trunking Protocol (DTP) printer */
19 
20 #ifdef HAVE_CONFIG_H
21 #include "config.h"
22 #endif
23 
24 #include <netdissect-stdinc.h>
25 
26 #include "netdissect.h"
27 #include "addrtoname.h"
28 #include "extract.h"
29 
30 static const char tstr[] = " [|dtp]";
31 
32 #define DTP_HEADER_LEN			1
33 #define DTP_DOMAIN_TLV			0x0001
34 #define DTP_STATUS_TLV			0x0002
35 #define DTP_DTP_TYPE_TLV		0x0003
36 #define DTP_NEIGHBOR_TLV		0x0004
37 
38 static const struct tok dtp_tlv_values[] = {
39     { DTP_DOMAIN_TLV, "Domain TLV"},
40     { DTP_STATUS_TLV, "Status TLV"},
41     { DTP_DTP_TYPE_TLV, "DTP type TLV"},
42     { DTP_NEIGHBOR_TLV, "Neighbor TLV"},
43     { 0, NULL}
44 };
45 
46 void
dtp_print(netdissect_options * ndo,const u_char * pptr,u_int length)47 dtp_print (netdissect_options *ndo, const u_char *pptr, u_int length)
48 {
49     int type, len;
50     const u_char *tptr;
51 
52     if (length < DTP_HEADER_LEN)
53         goto trunc;
54 
55     tptr = pptr;
56 
57     ND_TCHECK2(*tptr, DTP_HEADER_LEN);
58 
59     ND_PRINT((ndo, "DTPv%u, length %u",
60            (*tptr),
61            length));
62 
63     /*
64      * In non-verbose mode, just print version.
65      */
66     if (ndo->ndo_vflag < 1) {
67 	return;
68     }
69 
70     tptr += DTP_HEADER_LEN;
71 
72     while (tptr < (pptr+length)) {
73 
74         ND_TCHECK2(*tptr, 4);
75 	type = EXTRACT_16BITS(tptr);
76         len  = EXTRACT_16BITS(tptr+2);
77        /* XXX: should not be but sometimes it is, see the test captures */
78         if (type == 0)
79             return;
80         ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
81                tok2str(dtp_tlv_values, "Unknown", type),
82                type, len));
83 
84         /* infinite loop check */
85         if (len < 4)
86             goto invalid;
87         ND_TCHECK2(*tptr, len);
88 
89         switch (type) {
90 	case DTP_DOMAIN_TLV:
91 		ND_PRINT((ndo, ", "));
92 		fn_printzp(ndo, tptr+4, len-4, pptr+length);
93 		break;
94 
95 	case DTP_STATUS_TLV:
96 	case DTP_DTP_TYPE_TLV:
97                 if (len < 5)
98                     goto invalid;
99                 ND_PRINT((ndo, ", 0x%x", *(tptr+4)));
100                 break;
101 
102 	case DTP_NEIGHBOR_TLV:
103                 if (len < 10)
104                     goto invalid;
105                 ND_PRINT((ndo, ", %s", etheraddr_string(ndo, tptr+4)));
106                 break;
107 
108         default:
109             break;
110         }
111         tptr += len;
112     }
113 
114     return;
115 
116  invalid:
117     ND_PRINT((ndo, "%s", istr));
118     return;
119  trunc:
120     ND_PRINT((ndo, "%s", tstr));
121 }
122 
123 /*
124  * Local Variables:
125  * c-style: whitesmith
126  * c-basic-offset: 4
127  * End:
128  */
129