The Tcpdump Group git mirrors - tcpdump/blob - print-tftp.c

   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
  62 /* op code to string mapping */
  63 static const struct tok op2str[] = {
  64         { RRQ,          "RRQ" },        /* read request */
  65         { WRQ,          "WRQ" },        /* write request */
  66         { DATA,         "DATA" },       /* data packet */
  67         { ACK,          "ACK" },        /* acknowledgement */
  68         { TFTP_ERROR,   "ERROR" },      /* error code */
  69         { OACK,         "OACK" },       /* option acknowledgement */
  70         { 0,            NULL }
  71 };
  72
  73 /* error code to string mapping */
  74 static const struct tok err2str[] = {
  75         { EUNDEF,       "EUNDEF" },     /* not defined */
  76         { ENOTFOUND,    "ENOTFOUND" },  /* file not found */
  77         { EACCESS,      "EACCESS" },    /* access violation */
  78         { ENOSPACE,     "ENOSPACE" },   /* disk full or allocation exceeded */
  79         { EBADOP,       "EBADOP" },     /* illegal TFTP operation */
  80         { EBADID,       "EBADID" },     /* unknown transfer ID */
  81         { EEXISTS,      "EEXISTS" },    /* file already exists */
  82         { ENOUSER,      "ENOUSER" },    /* no such user */
  83         { 0,            NULL }
  84 };
  85
  86 /*
  87  * Print trivial file transfer program requests
  88  */
  89 void
  90 tftp_print(netdissect_options *ndo,
  91            const u_char *bp, u_int length)
  92 {
  93         const char *cp;
  94         u_int opcode;
  95         u_int ui;
  96
  97         ndo->ndo_protocol = "tftp";
  98
  99         /* Print protocol */
 100         ND_PRINT("TFTP");
 101         /* Print length */
 102         ND_PRINT(", length %u", length);
 103
 104         /* Print tftp request type */
 105         if (length < 2)
 106                 goto trunc;
 107         ND_TCHECK_2(bp);
 108         opcode = GET_BE_U_2(bp);
 109         cp = tok2str(op2str, "tftp-#%u", opcode);
 110         ND_PRINT(", %s", cp);
 111         /* Bail if bogus opcode */
 112         if (*cp == 't')
 113                 return;
 114         bp += 2;
 115         length -= 2;
 116
 117         switch (opcode) {
 118
 119         case RRQ:
 120         case WRQ:
 121                 if (length == 0)
 122                         goto trunc;
 123                 ND_PRINT(" ");
 124                 /* Print filename */
 125                 ND_PRINT("\"");
 126                 ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
 127                 ND_PRINT("\"");
 128                 if (ui == 0)
 129                         goto trunc;
 130                 bp += ui;
 131                 length -= ui;
 132
 133                 /* Print the mode - RRQ and WRQ only */
 134                 if (length == 0)
 135                         goto trunc;     /* no mode */
 136                 ND_PRINT(" ");
 137                 ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
 138                 if (ui == 0)
 139                         goto trunc;
 140                 bp += ui;
 141                 length -= ui;
 142
 143                 /* Print options, if any */
 144                 while (length != 0) {
 145                         ND_TCHECK_1(bp);
 146                         if (GET_U_1(bp) != '\0')
 147                                 ND_PRINT(" ");
 148                         ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
 149                         if (ui == 0)
 150                                 goto trunc;
 151                         bp += ui;
 152                         length -= ui;
 153                 }
 154                 break;
 155
 156         case OACK:
 157                 /* Print options */
 158                 while (length != 0) {
 159                         ND_TCHECK_1(bp);
 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_TCHECK_2(bp);
 175                 ND_PRINT(" block %u", GET_BE_U_2(bp));
 176                 break;
 177
 178         case TFTP_ERROR:
 179                 /* Print error code string */
 180                 if (length < 2)
 181                         goto trunc;     /* no error code */
 182                 ND_TCHECK_2(bp);
 183                 ND_PRINT(" %s", tok2str(err2str, "tftp-err-#%u \"",
 184                                        GET_BE_U_2(bp)));
 185                 bp += 2;
 186                 length -= 2;
 187                 /* Print error message string */
 188                 if (length == 0)
 189                         goto trunc;     /* no error message */
 190                 ND_PRINT(" \"");
 191                 ui = nd_printztn(ndo, bp, length, ndo->ndo_snapend);
 192                 ND_PRINT("\"");
 193                 if (ui == 0)
 194                         goto trunc;
 195                 break;
 196
 197         default:
 198                 /* We shouldn't get here */
 199                 ND_PRINT("(unknown #%u)", opcode);
 200                 break;
 201         }
 202         return;
 203 trunc:
 204         nd_print_trunc(ndo);
 205         return;
 206 }