tftp.c

   1 /* ------------------------------------------------------------------------- */
   2 /* tftp.c                                                                    */
   3 /*                                                                           */
   4 /* A simple tftp client for busybox.                                         */
   5 /* Tries to follow RFC1350.                                                  */
   6 /* Only "octet" mode and 512-byte data blocks are supported.                 */
   7 /*                                                                           */
   8 /* Copyright (C) 2001 Magnus Damm <damm@opensource.se>                       */
   9 /*                                                                           */
  10 /* Parts of the code based on:                                               */
  11 /*                                                                           */
  12 /* atftp:  Copyright (C) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca>   */
  13 /*                        and Remi Lefebvre <remi@debian.org>                */
  14 /*                                                                           */
  15 /* utftp:  Copyright (C) 1999 Uwe Ohse <uwe@ohse.de>                         */
  16 /*                                                                           */
  17 /* This program is free software; you can redistribute it and/or modify      */
  18 /* it under the terms of the GNU General Public License as published by      */
  19 /* the Free Software Foundation; either version 2 of the License, or         */
  20 /* (at your option) any later version.                                       */
  21 /*                                                                           */
  22 /* This program is distributed in the hope that it will be useful,           */
  23 /* but WITHOUT ANY WARRANTY; without even the implied warranty of            */
  24 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU          */
  25 /* General Public License for more details.                                  */
  26 /*                                                                           */
  27 /* You should have received a copy of the GNU General Public License         */
  28 /* along with this program; if not, write to the Free Software               */
  29 /* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA   */
  30 /*                                                                           */
  31 /* ------------------------------------------------------------------------- */
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38 #include <sys/time.h>
  39 #include <sys/stat.h>
  40 #include <netdb.h>
  41 #include <netinet/in.h>
  42 #include <arpa/inet.h>
  43 #include <unistd.h>
  44 #include <fcntl.h>
  45
  46 #include "busybox.h"
  47
  48 //#define BB_FEATURE_TFTP_DEBUG
  49
  50 /* we don't need #ifdefs with these constants and optimization... */
  51
  52 #ifdef BB_FEATURE_TFTP_GET
  53 #define BB_TFTP_GET (1 << 0)
  54 #else
  55 #define BB_TFTP_GET 0
  56 #endif
  57
  58 #ifdef BB_FEATURE_TFTP_PUT
  59 #define BB_TFTP_PUT (1 << 1)
  60 #else
  61 #define BB_TFTP_PUT 0
  62 #endif
  63
  64 #ifdef BB_FEATURE_TFTP_DEBUG
  65 #define BB_TFTP_DEBUG 1
  66 #else
  67 #define BB_TFTP_DEBUG 0
  68 #endif
  69
  70 #define BB_TFTP_NO_RETRIES 5
  71 #define BB_TFTP_TIMEOUT    5    /* seconds */
  72
  73 #define RRQ     1                       /* read request */
  74 #define WRQ     2                       /* write request */
  75 #define DATA    3               /* data packet */
  76 #define ACK     4                       /* acknowledgement */
  77 #define ERROR   5               /* error code */
  78
  79 #define BUFSIZE (512+4)
  80
  81 static const char *tftp_error_msg[] = {
  82         "Undefined error",
  83         "File not found",
  84         "Access violation",
  85         "Disk full or allocation error",
  86         "Illegal TFTP operation",
  87         "Unknown transfer ID",
  88         "File already exists",
  89         "No such user"
  90 };
  91
  92 static inline int tftp(int cmd, struct hostent *host,
  93                                            char *serverfile, int localfd, int port)
  94 {
  95         struct sockaddr_in sa;
  96         int socketfd;
  97         struct timeval tv;
  98         fd_set rfds;
  99         struct sockaddr_in from;
 100         socklen_t fromlen;
 101         char *cp;
 102         unsigned short tmp;
 103         int len, opcode, finished;
 104         int timeout, block_nr;
 105
 106         RESERVE_BB_BUFFER(buf, BUFSIZE);
 107
 108         opcode = finished = timeout = 0;
 109         block_nr = 1;
 110
 111         if ((socketfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
 112                 perror_msg("socket");
 113                 return EXIT_FAILURE;
 114         }
 115
 116         len = sizeof(sa);
 117
 118         memset(&sa, 0, len);
 119         bind(socketfd, (struct sockaddr *)&sa, len);
 120
 121         sa.sin_family = host->h_addrtype;
 122         sa.sin_port = htons(port);
 123         memcpy(&sa.sin_addr, (struct in_addr *) host->h_addr,
 124                    sizeof(sa.sin_addr));
 125
 126         /* build opcode */
 127
 128         if (cmd & BB_TFTP_GET) {
 129                 opcode = RRQ;
 130         }
 131
 132         if (cmd & BB_TFTP_PUT) {
 133                 opcode = WRQ;
 134         }
 135
 136         while (1) {
 137
 138
 139                 /* build packet of type "opcode" */
 140
 141
 142                 cp = buf;
 143
 144                 *((unsigned short *) cp) = htons(opcode);
 145
 146                 cp += 2;
 147
 148                 /* add filename and mode */
 149
 150                 if ((BB_TFTP_GET && (opcode == RRQ)) ||
 151                         (BB_TFTP_PUT && (opcode == WRQ))) {
 152
 153                         while (cp != &buf[BUFSIZE - 1]) {
 154                                 if ((*cp = *serverfile++) == '\0')
 155                                         break;
 156                                 cp++;
 157                         }
 158
 159                         if ((*cp != '\0') || (&buf[BUFSIZE - 1] - cp) < 7) {
 160                                 error_msg("too long server-filename");
 161                                 break;
 162                         }
 163
 164                         memcpy(cp + 1, "octet", 6);
 165                         cp += 7;
 166                 }
 167
 168                 /* add ack and data */
 169
 170                 if ((BB_TFTP_GET && (opcode == ACK)) ||
 171                         (BB_TFTP_PUT && (opcode == DATA))) {
 172
 173                         *((unsigned short *) cp) = htons(block_nr);
 174
 175                         cp += 2;
 176
 177                         block_nr++;
 178
 179                         if (BB_TFTP_PUT && (opcode == DATA)) {
 180                                 len = read(localfd, cp, BUFSIZE - 4);
 181
 182                                 if (len < 0) {
 183                                         perror_msg("read");
 184                                         break;
 185                                 }
 186
 187                                 if (len != (BUFSIZE - 4)) {
 188                                         finished++;
 189                                 }
 190
 191                                 cp += len;
 192                         } else if (finished) {
 193                                 break;
 194                         }
 195                 }
 196
 197
 198                 /* send packet */
 199
 200
 201                 do {
 202
 203                         len = cp - buf;
 204
 205                         if (BB_TFTP_DEBUG) {
 206                                 printf("sending %u bytes\n", len);
 207
 208                                 for (cp = buf; cp < &buf[len]; cp++)
 209                                         printf("%02x ", *cp);
 210                                 printf("\n");
 211                         }
 212
 213                         if (sendto(socketfd, buf, len, 0,
 214                                            (struct sockaddr *) &sa, sizeof(sa)) < 0) {
 215                                 perror_msg("send");
 216                                 len = -1;
 217                                 break;
 218                         }
 219
 220
 221                         /* receive packet */
 222
 223
 224                         memset(&from, 0, sizeof(from));
 225                         fromlen = sizeof(from);
 226
 227                         tv.tv_sec = BB_TFTP_TIMEOUT;
 228                         tv.tv_usec = 0;
 229
 230                         FD_ZERO(&rfds);
 231                         FD_SET(socketfd, &rfds);
 232
 233                         switch (select(FD_SETSIZE, &rfds, NULL, NULL, &tv)) {
 234                         case 1:
 235                                 len = recvfrom(socketfd, buf,
 236                                                            BUFSIZE, 0,
 237                                                            (struct sockaddr *) &from, &fromlen);
 238
 239                                 if (len < 0) {
 240                                         perror_msg("recvfrom");
 241                                         break;
 242                                 }
 243
 244                                 timeout = 0;
 245
 246                                 if (sa.sin_port == htons(port)) {
 247                                         sa.sin_port = from.sin_port;
 248                                         break;
 249                                 }
 250
 251                                 if (sa.sin_port == from.sin_port) {
 252                                         break;
 253                                 }
 254
 255                                 /* fall-through for bad packets! */
 256                                 /* discard the packet - treat as timeout */
 257
 258                         case 0:
 259                                 error_msg("timeout");
 260
 261                                 if (!timeout) {
 262                                         timeout = BB_TFTP_NO_RETRIES;
 263                                 } else {
 264                                         timeout--;
 265                                 }
 266
 267                                 if (!timeout) {
 268                                         len = -1;
 269                                         error_msg("last timeout");
 270                                 }
 271                                 break;
 272
 273                         default:
 274                                 perror_msg("select");
 275                                 len = -1;
 276                         }
 277
 278                 } while (timeout && (len >= 0));
 279
 280                 if (len < 0) {
 281                         break;
 282                 }
 283
 284                 /* process received packet */
 285
 286
 287                 opcode = ntohs(*((unsigned short *) buf));
 288                 tmp = ntohs(*((unsigned short *) &buf[2]));
 289
 290                 if (BB_TFTP_DEBUG) {
 291                         printf("received %d bytes: %04x %04x\n", len, opcode, tmp);
 292                 }
 293
 294                 if (BB_TFTP_GET && (opcode == DATA)) {
 295
 296                         if (tmp == block_nr) {
 297                                 len = write(localfd, &buf[4], len - 4);
 298
 299                                 if (len < 0) {
 300                                         perror_msg("write");
 301                                         break;
 302                                 }
 303
 304                                 if (len != (BUFSIZE - 4)) {
 305                                         finished++;
 306                                 }
 307
 308                                 opcode = ACK;
 309                                 continue;
 310                         }
 311                 }
 312
 313                 if (BB_TFTP_PUT && (opcode == ACK)) {
 314
 315                         if (tmp == (block_nr - 1)) {
 316                                 if (finished) {
 317                                         break;
 318                                 }
 319
 320                                 opcode = DATA;
 321                                 continue;
 322                         }
 323                 }
 324
 325                 if (opcode == ERROR) {
 326                         char *msg = NULL;
 327
 328                         if (buf[4] != '\0') {
 329                                 msg = &buf[4];
 330                                 buf[BUFSIZE - 1] = '\0';
 331                         } else if (tmp < (sizeof(tftp_error_msg) / sizeof(char *))) {
 332                                 msg = (char *) tftp_error_msg[tmp];
 333                         }
 334
 335                         if (msg) {
 336                                 error_msg("server says: %s", msg);
 337                         }
 338
 339                         break;
 340                 }
 341         }
 342
 343         close(socketfd);
 344
 345         return finished ? EXIT_SUCCESS : EXIT_FAILURE;
 346 }
 347
 348 int tftp_main(int argc, char **argv)
 349 {
 350         char *cp, *s;
 351         char *serverstr;
 352         struct hostent *host;
 353         char *serverfile;
 354         char *localfile;
 355         int cmd, flags, fd, bad;
 356
 357         host = (void *) serverstr = serverfile = localfile = NULL;
 358         flags = cmd = 0;
 359         bad = 1;
 360
 361         if (argc > 3) {
 362                 if (BB_TFTP_GET && (strcmp(argv[1], "get") == 0)) {
 363                         cmd = BB_TFTP_GET;
 364                         flags = O_WRONLY | O_CREAT;
 365                         serverstr = argv[2];
 366                         localfile = argv[3];
 367                 }
 368
 369                 if (BB_TFTP_PUT && (strcmp(argv[1], "put") == 0)) {
 370                         cmd = BB_TFTP_PUT;
 371                         flags = O_RDONLY;
 372                         localfile = argv[2];
 373                         serverstr = argv[3];
 374                 }
 375
 376         }
 377
 378         if (!(cmd & (BB_TFTP_GET | BB_TFTP_PUT))) {
 379                 show_usage();
 380         }
 381
 382         for (cp = serverstr; *cp != '\0'; cp++)
 383                 if (*cp == ':')
 384                         break;
 385
 386         if (*cp == ':') {
 387
 388                 serverfile = cp + 1;
 389
 390                 s = xstrdup(serverstr);
 391                 s[cp - serverstr] = '\0';
 392
 393                 host = xgethostbyname(s);
 394
 395                 free(s);
 396         }
 397
 398         if (BB_TFTP_DEBUG) {
 399                 printf("using server \"%s\", serverfile \"%s\","
 400                            "localfile \"%s\".\n",
 401                            inet_ntoa(*((struct in_addr *) host->h_addr)),
 402                            serverfile, localfile);
 403         }
 404
 405         if ((fd = open(localfile, flags, 0644)) < 0) {
 406                 perror_msg_and_die("local file");
 407         }
 408
 409         flags = tftp(cmd, host, serverfile, fd, 69);
 410
 411         close(fd);
 412
 413         return flags;
 414 }