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      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 
     61 static const char tstr[] = " [|tftp]";
     62 
     63 /* op code to string mapping */
     64 static 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 */
     75 static 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  */
     90 void
     91 tftp_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;
    200 trunc:
    201 	ND_PRINT((ndo, "%s", tstr));
    202 	return;
    203 }
    204