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  * Format and print trivial file transfer protocol packets.
  22  */
  23
  24 #define NETDISSECT_REWORKED
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <tcpdump-stdinc.h>
  30
  31 #include <string.h>
  32
  33 #include "interface.h"
  34 #include "extract.h"
  35
  36 /*
  37  * Trivial File Transfer Protocol (IEN-133)
  38  */
  39
  40 /*
  41  * Packet types.
  42  */
  43 #define RRQ     01                      /* read request */
  44 #define WRQ     02                      /* write request */
  45 #define DATA    03                      /* data packet */
  46 #define ACK     04                      /* acknowledgement */
  47 #define TFTP_ERROR      05                      /* error code */
  48 #define OACK    06                      /* option acknowledgement */
  49
  50 struct  tftphdr {
  51         unsigned short  th_opcode;              /* packet type */
  52         union {
  53                 unsigned short  tu_block;       /* block # */
  54                 unsigned short  tu_code;        /* error code */
  55                 char    tu_stuff[1];    /* request packet stuff */
  56         } th_u;
  57         char    th_data[1];             /* data or error string */
  58 };
  59
  60 #define th_block        th_u.tu_block
  61 #define th_code         th_u.tu_code
  62 #define th_stuff        th_u.tu_stuff
  63 #define th_msg          th_data
  64
  65 /*
  66  * Error codes.
  67  */
  68 #define EUNDEF          0               /* not defined */
  69 #define ENOTFOUND       1               /* file not found */
  70 #define EACCESS         2               /* access violation */
  71 #define ENOSPACE        3               /* disk full or allocation exceeded */
  72 #define EBADOP          4               /* illegal TFTP operation */
  73 #define EBADID          5               /* unknown transfer ID */
  74 #define EEXISTS         6               /* file already exists */
  75 #define ENOUSER         7               /* no such user */
  76
  77 static const char tstr[] = " [|tftp]";
  78
  79 /* op code to string mapping */
  80 static const struct tok op2str[] = {
  81         { RRQ,          "RRQ" },        /* read request */
  82         { WRQ,          "WRQ" },        /* write request */
  83         { DATA,         "DATA" },       /* data packet */
  84         { ACK,          "ACK" },        /* acknowledgement */
  85         { TFTP_ERROR,   "ERROR" },      /* error code */
  86         { OACK,         "OACK" },       /* option acknowledgement */
  87         { 0,            NULL }
  88 };
  89
  90 /* error code to string mapping */
  91 static const struct tok err2str[] = {
  92         { EUNDEF,       "EUNDEF" },     /* not defined */
  93         { ENOTFOUND,    "ENOTFOUND" },  /* file not found */
  94         { EACCESS,      "EACCESS" },    /* access violation */
  95         { ENOSPACE,     "ENOSPACE" },   /* disk full or allocation exceeded */
  96         { EBADOP,       "EBADOP" },     /* illegal TFTP operation */
  97         { EBADID,       "EBADID" },     /* unknown transfer ID */
  98         { EEXISTS,      "EEXISTS" },    /* file already exists */
  99         { ENOUSER,      "ENOUSER" },    /* no such user */
 100         { 0,            NULL }
 101 };
 102
 103 /*
 104  * Print trivial file transfer program requests
 105  */
 106 void
 107 tftp_print(netdissect_options *ndo,
 108            register const u_char *bp, u_int length)
 109 {
 110         register const struct tftphdr *tp;
 111         register const char *cp;
 112         register const u_char *p;
 113         register int opcode, i;
 114
 115         tp = (const struct tftphdr *)bp;
 116
 117         /* Print length */
 118         ND_PRINT((ndo, " %d", length));
 119
 120         /* Print tftp request type */
 121         ND_TCHECK(tp->th_opcode);
 122         opcode = EXTRACT_16BITS(&tp->th_opcode);
 123         cp = tok2str(op2str, "tftp-#%d", opcode);
 124         ND_PRINT((ndo, " %s", cp));
 125         /* Bail if bogus opcode */
 126         if (*cp == 't')
 127                 return;
 128
 129         switch (opcode) {
 130
 131         case RRQ:
 132         case WRQ:
 133         case OACK:
 134                 p = (u_char *)tp->th_stuff;
 135                 ND_PRINT((ndo, " "));
 136                 /* Print filename or first option */
 137                 if (opcode != OACK)
 138                         ND_PRINT((ndo, "\""));
 139                 i = fn_print(ndo, p, ndo->ndo_snapend);
 140                 if (opcode != OACK)
 141                         ND_PRINT((ndo, "\""));
 142
 143                 /* Print the mode (RRQ and WRQ only) and any options */
 144                 while ((p = (const u_char *)strchr((const char *)p, '\0')) != NULL) {
 145                         if (length <= (u_int)(p - (const u_char *)&tp->th_block))
 146                                 break;
 147                         p++;
 148                         if (*p != '\0') {
 149                                 ND_PRINT((ndo, " "));
 150                                 fn_print(ndo, p, ndo->ndo_snapend);
 151                         }
 152                 }
 153
 154                 if (i)
 155                         goto trunc;
 156                 break;
 157
 158         case ACK:
 159         case DATA:
 160                 ND_TCHECK(tp->th_block);
 161                 ND_PRINT((ndo, " block %d", EXTRACT_16BITS(&tp->th_block)));
 162                 break;
 163
 164         case TFTP_ERROR:
 165                 /* Print error code string */
 166                 ND_TCHECK(tp->th_code);
 167                 ND_PRINT((ndo, " %s \"", tok2str(err2str, "tftp-err-#%d \"",
 168                                        EXTRACT_16BITS(&tp->th_code))));
 169                 /* Print error message string */
 170                 i = fn_print(ndo, (const u_char *)tp->th_data, ndo->ndo_snapend);
 171                 ND_PRINT((ndo, "\""));
 172                 if (i)
 173                         goto trunc;
 174                 break;
 175
 176         default:
 177                 /* We shouldn't get here */
 178                 ND_PRINT((ndo, "(unknown #%d)", opcode));
 179                 break;
 180         }
 181         return;
 182 trunc:
 183         ND_PRINT((ndo, "%s", tstr));
 184         return;
 185 }