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#include <sys/cdefs.h>
25#ifndef lint
26__RCSID("$NetBSD: print-tftp.c,v 1.9 2023/08/17 20:19:40 christos Exp $");
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include <config.h>
31#endif
32
33#include "netdissect-stdinc.h"
34
35#include "netdissect.h"
36#include "extract.h"
37
38/*
39 * Trivial File Transfer Protocol (IEN-133)
40 */
41
42/*
43 * Packet types.
44 */
45#define	RRQ	01			/* read request */
46#define	WRQ	02			/* write request */
47#define	DATA	03			/* data packet */
48#define	ACK	04			/* acknowledgement */
49#define	TFTP_ERROR	05			/* error code */
50#define OACK	06			/* option acknowledgement */
51
52/*
53 * Error codes.
54 */
55#define	EUNDEF		0		/* not defined */
56#define	ENOTFOUND	1		/* file not found */
57#define	EACCESS		2		/* access violation */
58#define	ENOSPACE	3		/* disk full or allocation exceeded */
59#define	EBADOP		4		/* illegal TFTP operation */
60#define	EBADID		5		/* unknown transfer ID */
61#define	EEXISTS		6		/* file already exists */
62#define	ENOUSER		7		/* no such user */
63
64
65/* op code to string mapping */
66static const struct tok op2str[] = {
67	{ RRQ,		"RRQ" },	/* read request */
68	{ WRQ,		"WRQ" },	/* write request */
69	{ DATA,		"DATA" },	/* data packet */
70	{ ACK,		"ACK" },	/* acknowledgement */
71	{ TFTP_ERROR,	"ERROR" },	/* error code */
72	{ OACK,		"OACK" },	/* option acknowledgement */
73	{ 0,		NULL }
74};
75
76/* error code to string mapping */
77static const struct tok err2str[] = {
78	{ EUNDEF,	"EUNDEF" },	/* not defined */
79	{ ENOTFOUND,	"ENOTFOUND" },	/* file not found */
80	{ EACCESS,	"EACCESS" },	/* access violation */
81	{ ENOSPACE,	"ENOSPACE" },	/* disk full or allocation exceeded */
82	{ EBADOP,	"EBADOP" },	/* illegal TFTP operation */
83	{ EBADID,	"EBADID" },	/* unknown transfer ID */
84	{ EEXISTS,	"EEXISTS" },	/* file already exists */
85	{ ENOUSER,	"ENOUSER" },	/* no such user */
86	{ 0,		NULL }
87};
88
89/*
90 * Print trivial file transfer program requests
91 */
92void
93tftp_print(netdissect_options *ndo,
94           const u_char *bp, u_int length)
95{
96	const char *cp;
97	u_int opcode;
98	u_int ui;
99
100	ndo->ndo_protocol = "tftp";
101
102	/* Print protocol */
103	nd_print_protocol_caps(ndo);
104	/* Print length */
105	ND_PRINT(", length %u", length);
106
107	/* Print tftp request type */
108	if (length < 2)
109		goto trunc;
110	opcode = GET_BE_U_2(bp);
111	cp = tok2str(op2str, "tftp-#%u", opcode);
112	ND_PRINT(", %s", cp);
113	/* Bail if bogus opcode */
114	if (*cp == 't')
115		return;
116	bp += 2;
117	length -= 2;
118
119	switch (opcode) {
120
121	case RRQ:
122	case WRQ:
123		if (length == 0)
124			goto trunc;
125		ND_PRINT(" ");
126		/* Print filename */
127		ND_PRINT("\"");
128		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
129		ND_PRINT("\"");
130		if (ui == 0)
131			goto trunc;
132		bp += ui;
133		length -= ui;
134
135		/* Print the mode - RRQ and WRQ only */
136		if (length == 0)
137			goto trunc;	/* no mode */
138		ND_PRINT(" ");
139		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
140		if (ui == 0)
141			goto trunc;
142		bp += ui;
143		length -= ui;
144
145		/* Print options, if any */
146		while (length != 0) {
147			if (GET_U_1(bp) != '\0')
148				ND_PRINT(" ");
149			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
150			if (ui == 0)
151				goto trunc;
152			bp += ui;
153			length -= ui;
154		}
155		break;
156
157	case OACK:
158		/* Print options */
159		while (length != 0) {
160			if (GET_U_1(bp) != '\0')
161				ND_PRINT(" ");
162			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
163			if (ui == 0)
164				goto trunc;
165			bp += ui;
166			length -= ui;
167		}
168		break;
169
170	case ACK:
171	case DATA:
172		if (length < 2)
173			goto trunc;	/* no block number */
174		ND_PRINT(" block %u", GET_BE_U_2(bp));
175		break;
176
177	case TFTP_ERROR:
178		/* Print error code string */
179		if (length < 2)
180			goto trunc;	/* no error code */
181		ND_PRINT(" %s", tok2str(err2str, "tftp-err-#%u \"",
182				       GET_BE_U_2(bp)));
183		bp += 2;
184		length -= 2;
185		/* Print error message string */
186		if (length == 0)
187			goto trunc;	/* no error message */
188		ND_PRINT(" \"");
189		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
190		ND_PRINT("\"");
191		if (ui == 0)
192			goto trunc;
193		break;
194
195	default:
196		/* We shouldn't get here */
197		ND_PRINT("(unknown #%u)", opcode);
198		break;
199	}
200	return;
201trunc:
202	nd_print_trunc(ndo);
203}
204