nexmon – Rev 1
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/*
* Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Format and print trivial file transfer protocol packets.
*/
#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include <string.h>
#include "interface.h"
#include "extract.h"
/*
* Trivial File Transfer Protocol (IEN-133)
*/
/*
* Packet types.
*/
#define RRQ 01 /* read request */
#define WRQ 02 /* write request */
#define DATA 03 /* data packet */
#define ACK 04 /* acknowledgement */
#define TFTP_ERROR 05 /* error code */
#define OACK 06 /* option acknowledgement */
struct tftphdr {
unsigned short th_opcode; /* packet type */
union {
unsigned short tu_block; /* block # */
unsigned short tu_code; /* error code */
char tu_stuff[1]; /* request packet stuff */
} th_u;
char th_data[1]; /* data or error string */
};
#define th_block th_u.tu_block
#define th_code th_u.tu_code
#define th_stuff th_u.tu_stuff
#define th_msg th_data
/*
* Error codes.
*/
#define EUNDEF 0 /* not defined */
#define ENOTFOUND 1 /* file not found */
#define EACCESS 2 /* access violation */
#define ENOSPACE 3 /* disk full or allocation exceeded */
#define EBADOP 4 /* illegal TFTP operation */
#define EBADID 5 /* unknown transfer ID */
#define EEXISTS 6 /* file already exists */
#define ENOUSER 7 /* no such user */
static const char tstr[] = " [|tftp]";
/* op code to string mapping */
static const struct tok op2str[] = {
{ RRQ, "RRQ" }, /* read request */
{ WRQ, "WRQ" }, /* write request */
{ DATA, "DATA" }, /* data packet */
{ ACK, "ACK" }, /* acknowledgement */
{ TFTP_ERROR, "ERROR" }, /* error code */
{ OACK, "OACK" }, /* option acknowledgement */
{ 0, NULL }
};
/* error code to string mapping */
static const struct tok err2str[] = {
{ EUNDEF, "EUNDEF" }, /* not defined */
{ ENOTFOUND, "ENOTFOUND" }, /* file not found */
{ EACCESS, "EACCESS" }, /* access violation */
{ ENOSPACE, "ENOSPACE" }, /* disk full or allocation exceeded */
{ EBADOP, "EBADOP" }, /* illegal TFTP operation */
{ EBADID, "EBADID" }, /* unknown transfer ID */
{ EEXISTS, "EEXISTS" }, /* file already exists */
{ ENOUSER, "ENOUSER" }, /* no such user */
{ 0, NULL }
};
/*
* Print trivial file transfer program requests
*/
void
tftp_print(netdissect_options *ndo,
register const u_char *bp, u_int length)
{
register const struct tftphdr *tp;
register const char *cp;
register const u_char *p;
register int opcode, i;
tp = (const struct tftphdr *)bp;
/* Print length */
ND_PRINT((ndo, " %d", length));
/* Print tftp request type */
ND_TCHECK(tp->th_opcode);
opcode = EXTRACT_16BITS(&tp->th_opcode);
cp = tok2str(op2str, "tftp-#%d", opcode);
ND_PRINT((ndo, " %s", cp));
/* Bail if bogus opcode */
if (*cp == 't')
return;
switch (opcode) {
case RRQ:
case WRQ:
case OACK:
p = (u_char *)tp->th_stuff;
ND_PRINT((ndo, " "));
/* Print filename or first option */
if (opcode != OACK)
ND_PRINT((ndo, "\""));
i = fn_print(ndo, p, ndo->ndo_snapend);
if (opcode != OACK)
ND_PRINT((ndo, "\""));
/* Print the mode (RRQ and WRQ only) and any options */
while ((p = (const u_char *)strchr((const char *)p, '\0')) != NULL) {
if (length <= (u_int)(p - (const u_char *)&tp->th_block))
break;
p++;
if (*p != '\0') {
ND_PRINT((ndo, " "));
fn_print(ndo, p, ndo->ndo_snapend);
}
}
if (i)
goto trunc;
break;
case ACK:
case DATA:
ND_TCHECK(tp->th_block);
ND_PRINT((ndo, " block %d", EXTRACT_16BITS(&tp->th_block)));
break;
case TFTP_ERROR:
/* Print error code string */
ND_TCHECK(tp->th_code);
ND_PRINT((ndo, " %s \"", tok2str(err2str, "tftp-err-#%d \"",
EXTRACT_16BITS(&tp->th_code))));
/* Print error message string */
i = fn_print(ndo, (const u_char *)tp->th_data, ndo->ndo_snapend);
ND_PRINT((ndo, "\""));
if (i)
goto trunc;
break;
default:
/* We shouldn't get here */
ND_PRINT((ndo, "(unknown #%d)", opcode));
break;
}
return;
trunc:
ND_PRINT((ndo, "%s", tstr));
return;
}