print-tftp.c revision 327234 
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: Trivial File Transfer Protocol (TFTP) printer */
23
24#ifdef HAVE_CONFIG_H
25#include "config.h"
26#endif
27
28#include <netdissect-stdinc.h>
29
30#include <string.h>
31
32#include "netdissect.h"
33#include "extract.h"
34
35/*
36 * Trivial File Transfer Protocol (IEN-133)
37 */
38
39/*
40 * Packet types.
41 */
42#define	RRQ	01			/* read request */
43#define	WRQ	02			/* write request */
44#define	DATA	03			/* data packet */
45#define	ACK	04			/* acknowledgement */
46#define	TFTP_ERROR	05			/* error code */
47#define OACK	06			/* option acknowledgement */
48
49/*
50 * Error codes.
51 */
52#define	EUNDEF		0		/* not defined */
53#define	ENOTFOUND	1		/* file not found */
54#define	EACCESS		2		/* access violation */
55#define	ENOSPACE	3		/* disk full or allocation exceeded */
56#define	EBADOP		4		/* illegal TFTP operation */
57#define	EBADID		5		/* unknown transfer ID */
58#define	EEXISTS		6		/* file already exists */
59#define	ENOUSER		7		/* no such user */
60
61static const char tstr[] = " [|tftp]";
62
63/* op code to string mapping */
64static const struct tok op2str[] = {
65	{ RRQ,		"RRQ" },	/* read request */
66	{ WRQ,		"WRQ" },	/* write request */
67	{ DATA,		"DATA" },	/* data packet */
68	{ ACK,		"ACK" },	/* acknowledgement */
69	{ TFTP_ERROR,	"ERROR" },	/* error code */
70	{ OACK,		"OACK" },	/* option acknowledgement */
71	{ 0,		NULL }
72};
73
74/* error code to string mapping */
75static const struct tok err2str[] = {
76	{ EUNDEF,	"EUNDEF" },	/* not defined */
77	{ ENOTFOUND,	"ENOTFOUND" },	/* file not found */
78	{ EACCESS,	"EACCESS" },	/* access violation */
79	{ ENOSPACE,	"ENOSPACE" },	/* disk full or allocation exceeded */
80	{ EBADOP,	"EBADOP" },	/* illegal TFTP operation */
81	{ EBADID,	"EBADID" },	/* unknown transfer ID */
82	{ EEXISTS,	"EEXISTS" },	/* file already exists */
83	{ ENOUSER,	"ENOUSER" },	/* no such user */
84	{ 0,		NULL }
85};
86
87/*
88 * Print trivial file transfer program requests
89 */
90void
91tftp_print(netdissect_options *ndo,
92           register const u_char *bp, u_int length)
93{
94	register const char *cp;
95	register int opcode;
96	u_int ui;
97
98	/* Print length */
99	ND_PRINT((ndo, " %d", length));
100
101	/* Print tftp request type */
102	if (length < 2)
103		goto trunc;
104	ND_TCHECK_16BITS(bp);
105	opcode = EXTRACT_16BITS(bp);
106	cp = tok2str(op2str, "tftp-#%d", opcode);
107	ND_PRINT((ndo, " %s", cp));
108	/* Bail if bogus opcode */
109	if (*cp == 't')
110		return;
111	bp += 2;
112	length -= 2;
113
114	switch (opcode) {
115
116	case RRQ:
117	case WRQ:
118		if (length == 0)
119			goto trunc;
120		ND_PRINT((ndo, " "));
121		/* Print filename */
122		ND_PRINT((ndo, "\""));
123		ui = fn_printztn(ndo, bp, length, ndo->ndo_snapend);
124		ND_PRINT((ndo, "\""));
125		if (ui == 0)
126			goto trunc;
127		bp += ui;
128		length -= ui;
129
130		/* Print the mode - RRQ and WRQ only */
131		if (length == 0)
132			goto trunc;	/* no mode */
133		ND_PRINT((ndo, " "));
134		ui = fn_printztn(ndo, bp, length, ndo->ndo_snapend);
135		if (ui == 0)
136			goto trunc;
137		bp += ui;
138		length -= ui;
139
140		/* Print options, if any */
141		while (length != 0) {
142			ND_TCHECK(*bp);
143			if (*bp != '\0')
144				ND_PRINT((ndo, " "));
145			ui = fn_printztn(ndo, bp, length, ndo->ndo_snapend);
146			if (ui == 0)
147				goto trunc;
148			bp += ui;
149			length -= ui;
150		}
151		break;
152
153	case OACK:
154		/* Print options */
155		while (length != 0) {
156			ND_TCHECK(*bp);
157			if (*bp != '\0')
158				ND_PRINT((ndo, " "));
159			ui = fn_printztn(ndo, bp, length, ndo->ndo_snapend);
160			if (ui == 0)
161				goto trunc;
162			bp += ui;
163			length -= ui;
164		}
165		break;
166
167	case ACK:
168	case DATA:
169		if (length < 2)
170			goto trunc;	/* no block number */
171		ND_TCHECK_16BITS(bp);
172		ND_PRINT((ndo, " block %d", EXTRACT_16BITS(bp)));
173		break;
174
175	case TFTP_ERROR:
176		/* Print error code string */
177		if (length < 2)
178			goto trunc;	/* no error code */
179		ND_TCHECK_16BITS(bp);
180		ND_PRINT((ndo, " %s", tok2str(err2str, "tftp-err-#%d \"",
181				       EXTRACT_16BITS(bp))));
182		bp += 2;
183		length -= 2;
184		/* Print error message string */
185		if (length == 0)
186			goto trunc;	/* no error message */
187		ND_PRINT((ndo, " \""));
188		ui = fn_printztn(ndo, bp, length, ndo->ndo_snapend);
189		ND_PRINT((ndo, "\""));
190		if (ui == 0)
191			goto trunc;
192		break;
193
194	default:
195		/* We shouldn't get here */
196		ND_PRINT((ndo, "(unknown #%d)", opcode));
197		break;
198	}
199	return;
200trunc:
201	ND_PRINT((ndo, "%s", tstr));
202	return;
203}
204