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