xref: /freebsd/contrib/tcpdump/print-tftp.c (revision 56b17de1e8360fe131d425de20b5e75ff3ea897c)
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 <config.h>
25 
26 #include "netdissect-stdinc.h"
27 
28 #include "netdissect.h"
29 #include "extract.h"
30 
31 /*
32  * Trivial File Transfer Protocol (IEN-133)
33  */
34 
35 /*
36  * Packet types.
37  */
38 #define	RRQ	01			/* read request */
39 #define	WRQ	02			/* write request */
40 #define	DATA	03			/* data packet */
41 #define	ACK	04			/* acknowledgement */
42 #define	TFTP_ERROR	05			/* error code */
43 #define OACK	06			/* option acknowledgement */
44 
45 /*
46  * Error codes.
47  */
48 #define	EUNDEF		0		/* not defined */
49 #define	ENOTFOUND	1		/* file not found */
50 #define	EACCESS		2		/* access violation */
51 #define	ENOSPACE	3		/* disk full or allocation exceeded */
52 #define	EBADOP		4		/* illegal TFTP operation */
53 #define	EBADID		5		/* unknown transfer ID */
54 #define	EEXISTS		6		/* file already exists */
55 #define	ENOUSER		7		/* no such user */
56 
57 
58 /* op code to string mapping */
59 static const struct tok op2str[] = {
60 	{ RRQ,		"RRQ" },	/* read request */
61 	{ WRQ,		"WRQ" },	/* write request */
62 	{ DATA,		"DATA" },	/* data packet */
63 	{ ACK,		"ACK" },	/* acknowledgement */
64 	{ TFTP_ERROR,	"ERROR" },	/* error code */
65 	{ OACK,		"OACK" },	/* option acknowledgement */
66 	{ 0,		NULL }
67 };
68 
69 /* error code to string mapping */
70 static const struct tok err2str[] = {
71 	{ EUNDEF,	"EUNDEF" },	/* not defined */
72 	{ ENOTFOUND,	"ENOTFOUND" },	/* file not found */
73 	{ EACCESS,	"EACCESS" },	/* access violation */
74 	{ ENOSPACE,	"ENOSPACE" },	/* disk full or allocation exceeded */
75 	{ EBADOP,	"EBADOP" },	/* illegal TFTP operation */
76 	{ EBADID,	"EBADID" },	/* unknown transfer ID */
77 	{ EEXISTS,	"EEXISTS" },	/* file already exists */
78 	{ ENOUSER,	"ENOUSER" },	/* no such user */
79 	{ 0,		NULL }
80 };
81 
82 /*
83  * Print trivial file transfer program requests
84  */
85 void
86 tftp_print(netdissect_options *ndo,
87            const u_char *bp, u_int length)
88 {
89 	const char *cp;
90 	u_int opcode;
91 	u_int ui;
92 
93 	ndo->ndo_protocol = "tftp";
94 
95 	/* Print protocol */
96 	nd_print_protocol_caps(ndo);
97 	/* Print length */
98 	ND_PRINT(", length %u", length);
99 
100 	/* Print tftp request type */
101 	if (length < 2)
102 		goto trunc;
103 	opcode = GET_BE_U_2(bp);
104 	cp = tok2str(op2str, "tftp-#%u", opcode);
105 	ND_PRINT(", %s", cp);
106 	/* Bail if bogus opcode */
107 	if (*cp == 't')
108 		return;
109 	bp += 2;
110 	length -= 2;
111 
112 	switch (opcode) {
113 
114 	case RRQ:
115 	case WRQ:
116 		if (length == 0)
117 			goto trunc;
118 		ND_PRINT(" ");
119 		/* Print filename */
120 		ND_PRINT("\"");
121 		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
122 		ND_PRINT("\"");
123 		if (ui == 0)
124 			goto trunc;
125 		bp += ui;
126 		length -= ui;
127 
128 		/* Print the mode - RRQ and WRQ only */
129 		if (length == 0)
130 			goto trunc;	/* no mode */
131 		ND_PRINT(" ");
132 		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
133 		if (ui == 0)
134 			goto trunc;
135 		bp += ui;
136 		length -= ui;
137 
138 		/* Print options, if any */
139 		while (length != 0) {
140 			if (GET_U_1(bp) != '\0')
141 				ND_PRINT(" ");
142 			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
143 			if (ui == 0)
144 				goto trunc;
145 			bp += ui;
146 			length -= ui;
147 		}
148 		break;
149 
150 	case OACK:
151 		/* Print options */
152 		while (length != 0) {
153 			if (GET_U_1(bp) != '\0')
154 				ND_PRINT(" ");
155 			ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
156 			if (ui == 0)
157 				goto trunc;
158 			bp += ui;
159 			length -= ui;
160 		}
161 		break;
162 
163 	case ACK:
164 	case DATA:
165 		if (length < 2)
166 			goto trunc;	/* no block number */
167 		ND_PRINT(" block %u", GET_BE_U_2(bp));
168 		break;
169 
170 	case TFTP_ERROR:
171 		/* Print error code string */
172 		if (length < 2)
173 			goto trunc;	/* no error code */
174 		ND_PRINT(" %s", tok2str(err2str, "tftp-err-#%u \"",
175 				       GET_BE_U_2(bp)));
176 		bp += 2;
177 		length -= 2;
178 		/* Print error message string */
179 		if (length == 0)
180 			goto trunc;	/* no error message */
181 		ND_PRINT(" \"");
182 		ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
183 		ND_PRINT("\"");
184 		if (ui == 0)
185 			goto trunc;
186 		break;
187 
188 	default:
189 		/* We shouldn't get here */
190 		ND_PRINT("(unknown #%u)", opcode);
191 		break;
192 	}
193 	return;
194 trunc:
195 	nd_print_trunc(ndo);
196 }
197