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 * Format and print trivial file transfer protocol packets.
22 */
23
24 #define NETDISSECT_REWORKED
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include <tcpdump-stdinc.h>
30
31 #include <string.h>
32
33 #include "interface.h"
34 #include "extract.h"
35
36 /*
37 * Trivial File Transfer Protocol (IEN-133)
38 */
39
40 /*
41 * Packet types.
42 */
43 #define RRQ 01 /* read request */
44 #define WRQ 02 /* write request */
45 #define DATA 03 /* data packet */
46 #define ACK 04 /* acknowledgement */
47 #define TFTP_ERROR 05 /* error code */
48 #define OACK 06 /* option acknowledgement */
49
50 struct tftphdr {
51 unsigned short th_opcode; /* packet type */
52 union {
53 unsigned short tu_block; /* block # */
54 unsigned short tu_code; /* error code */
55 char tu_stuff[1]; /* request packet stuff */
56 } th_u;
57 char th_data[1]; /* data or error string */
58 };
59
60 #define th_block th_u.tu_block
61 #define th_code th_u.tu_code
62 #define th_stuff th_u.tu_stuff
63 #define th_msg th_data
64
65 /*
66 * Error codes.
67 */
68 #define EUNDEF 0 /* not defined */
69 #define ENOTFOUND 1 /* file not found */
70 #define EACCESS 2 /* access violation */
71 #define ENOSPACE 3 /* disk full or allocation exceeded */
72 #define EBADOP 4 /* illegal TFTP operation */
73 #define EBADID 5 /* unknown transfer ID */
74 #define EEXISTS 6 /* file already exists */
75 #define ENOUSER 7 /* no such user */
76
77 static const char tstr[] = " [|tftp]";
78
79 /* op code to string mapping */
80 static const struct tok op2str[] = {
81 { RRQ, "RRQ" }, /* read request */
82 { WRQ, "WRQ" }, /* write request */
83 { DATA, "DATA" }, /* data packet */
84 { ACK, "ACK" }, /* acknowledgement */
85 { TFTP_ERROR, "ERROR" }, /* error code */
86 { OACK, "OACK" }, /* option acknowledgement */
87 { 0, NULL }
88 };
89
90 /* error code to string mapping */
91 static const struct tok err2str[] = {
92 { EUNDEF, "EUNDEF" }, /* not defined */
93 { ENOTFOUND, "ENOTFOUND" }, /* file not found */
94 { EACCESS, "EACCESS" }, /* access violation */
95 { ENOSPACE, "ENOSPACE" }, /* disk full or allocation exceeded */
96 { EBADOP, "EBADOP" }, /* illegal TFTP operation */
97 { EBADID, "EBADID" }, /* unknown transfer ID */
98 { EEXISTS, "EEXISTS" }, /* file already exists */
99 { ENOUSER, "ENOUSER" }, /* no such user */
100 { 0, NULL }
101 };
102
103 /*
104 * Print trivial file transfer program requests
105 */
106 void
tftp_print(netdissect_options * ndo,register const u_char * bp,u_int length)107 tftp_print(netdissect_options *ndo,
108 register const u_char *bp, u_int length)
109 {
110 register const struct tftphdr *tp;
111 register const char *cp;
112 register const u_char *p;
113 register int opcode, i;
114
115 tp = (const struct tftphdr *)bp;
116
117 /* Print length */
118 ND_PRINT((ndo, " %d", length));
119
120 /* Print tftp request type */
121 ND_TCHECK(tp->th_opcode);
122 opcode = EXTRACT_16BITS(&tp->th_opcode);
123 cp = tok2str(op2str, "tftp-#%d", opcode);
124 ND_PRINT((ndo, " %s", cp));
125 /* Bail if bogus opcode */
126 if (*cp == 't')
127 return;
128
129 switch (opcode) {
130
131 case RRQ:
132 case WRQ:
133 case OACK:
134 p = (u_char *)tp->th_stuff;
135 ND_PRINT((ndo, " "));
136 /* Print filename or first option */
137 if (opcode != OACK)
138 ND_PRINT((ndo, "\""));
139 i = fn_print(ndo, p, ndo->ndo_snapend);
140 if (opcode != OACK)
141 ND_PRINT((ndo, "\""));
142
143 /* Print the mode (RRQ and WRQ only) and any options */
144 while ((p = (const u_char *)strchr((const char *)p, '\0')) != NULL) {
145 if (length <= (u_int)(p - (const u_char *)&tp->th_block))
146 break;
147 p++;
148 if (*p != '\0') {
149 ND_PRINT((ndo, " "));
150 fn_print(ndo, p, ndo->ndo_snapend);
151 }
152 }
153
154 if (i)
155 goto trunc;
156 break;
157
158 case ACK:
159 case DATA:
160 ND_TCHECK(tp->th_block);
161 ND_PRINT((ndo, " block %d", EXTRACT_16BITS(&tp->th_block)));
162 break;
163
164 case TFTP_ERROR:
165 /* Print error code string */
166 ND_TCHECK(tp->th_code);
167 ND_PRINT((ndo, " %s \"", tok2str(err2str, "tftp-err-#%d \"",
168 EXTRACT_16BITS(&tp->th_code))));
169 /* Print error message string */
170 i = fn_print(ndo, (const u_char *)tp->th_data, ndo->ndo_snapend);
171 ND_PRINT((ndo, "\""));
172 if (i)
173 goto trunc;
174 break;
175
176 default:
177 /* We shouldn't get here */
178 ND_PRINT((ndo, "(unknown #%d)", opcode));
179 break;
180 }
181 return;
182 trunc:
183 ND_PRINT((ndo, "%s", tstr));
184 return;
185 }
186