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 "netdissect.h"
31#include "extract.h"
32
33/*
34 * Trivial File Transfer Protocol (IEN-133)
35 */
36
37/*
38 * Packet types.
39 */
40#define	RRQ	01			/* read request */
41#define	WRQ	02			/* write request */
42#define	DATA	03			/* data packet */
43#define	ACK	04			/* acknowledgement */
44#define	TFTP_ERROR	05			/* error code */
45#define OACK	06			/* option acknowledgement */
46
47/*
48 * Error codes.
49 */
50#define	EUNDEF		0		/* not defined */
51#define	ENOTFOUND	1		/* file not found */
52#define	EACCESS		2		/* access violation */
53#define	ENOSPACE	3		/* disk full or allocation exceeded */
54#define	EBADOP		4		/* illegal TFTP operation */
55#define	EBADID		5		/* unknown transfer ID */
56#define	EEXISTS		6		/* file already exists */
57#define	ENOUSER		7		/* no such user */
58
59
60/* op code to string mapping */
61static const struct tok op2str[] = {
62	{ RRQ,		"RRQ" },	/* read request */
63	{ WRQ,		"WRQ" },	/* write request */
64	{ DATA,		"DATA" },	/* data packet */
65	{ ACK,		"ACK" },	/* acknowledgement */
66	{ TFTP_ERROR,	"ERROR" },	/* error code */
67	{ OACK,		"OACK" },	/* option acknowledgement */
68	{ 0,		NULL }
69};
70
71/* error code to string mapping */
72static const struct tok err2str[] = {
73	{ EUNDEF,	"EUNDEF" },	/* not defined */
74	{ ENOTFOUND,	"ENOTFOUND" },	/* file not found */
75	{ EACCESS,	"EACCESS" },	/* access violation */
76	{ ENOSPACE,	"ENOSPACE" },	/* disk full or allocation exceeded */
77	{ EBADOP,	"EBADOP" },	/* illegal TFTP operation */
78	{ EBADID,	"EBADID" },	/* unknown transfer ID */
79	{ EEXISTS,	"EEXISTS" },	/* file already exists */
80	{ ENOUSER,	"ENOUSER" },	/* no such user */
81	{ 0,		NULL }
82};
83
84/*
85 * Print trivial file transfer program requests
86 */
87void
88tftp_print(netdissect_options *ndo,
89           const u_char *bp, u_int length)
90{
91	const char *cp;
92	u_int opcode;
93	u_int ui;
94
95	ndo->ndo_protocol = "tftp";
96
97	/* Print protocol */
98	nd_print_protocol_caps(ndo);
99	/* Print length */
100	ND_PRINT(", length %u", length);
101
102	/* Print tftp request type */
103	if (length < 2)
104		goto trunc;
105	opcode = GET_BE_U_2(bp);
106	cp = tok2str(op2str, "tftp-#%u", opcode);
107	ND_PRINT(", %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(" ");
121		/* Print filename */
122		ND_PRINT("\"");
123		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
124		ND_PRINT("\"");
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(" ");
134		ui = nd_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			if (GET_U_1(bp) != '\0')
143				ND_PRINT(" ");
144			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
145			if (ui == 0)
146				goto trunc;
147			bp += ui;
148			length -= ui;
149		}
150		break;
151
152	case OACK:
153		/* Print options */
154		while (length != 0) {
155			if (GET_U_1(bp) != '\0')
156				ND_PRINT(" ");
157			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
158			if (ui == 0)
159				goto trunc;
160			bp += ui;
161			length -= ui;
162		}
163		break;
164
165	case ACK:
166	case DATA:
167		if (length < 2)
168			goto trunc;	/* no block number */
169		ND_PRINT(" block %u", GET_BE_U_2(bp));
170		break;
171
172	case TFTP_ERROR:
173		/* Print error code string */
174		if (length < 2)
175			goto trunc;	/* no error code */
176		ND_PRINT(" %s", tok2str(err2str, "tftp-err-#%u \"",
177				       GET_BE_U_2(bp)));
178		bp += 2;
179		length -= 2;
180		/* Print error message string */
181		if (length == 0)
182			goto trunc;	/* no error message */
183		ND_PRINT(" \"");
184		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
185		ND_PRINT("\"");
186		if (ui == 0)
187			goto trunc;
188		break;
189
190	default:
191		/* We shouldn't get here */
192		ND_PRINT("(unknown #%u)", opcode);
193		break;
194	}
195	return;
196trunc:
197	nd_print_trunc(ndo);
198}
199