sys/lib/libsa/tftp.c

   1 /*      $NetBSD: tftp.c,v 1.35 2014/03/20 03:13:18 christos Exp $        */
   2
   3 /*
   4  * Copyright (c) 1996
   5  *      Matthias Drochner.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  *
  27  */
  28
  29 /*
  30  * Simple TFTP implementation for libsa.
  31  * Assumes:
  32  *  - socket descriptor (int) at open_file->f_devdata
  33  *  - server host IP in global servip
  34  * Restrictions:
  35  *  - read only
  36  *  - lseek only with SEEK_SET or SEEK_CUR
  37  *  - no big time differences between transfers (<tftp timeout)
  38  */
  39
  40 /*
  41  * XXX Does not currently implement:
  42  * XXX
  43  * XXX LIBSA_NO_FS_CLOSE
  44  * XXX LIBSA_NO_FS_SEEK
  45  * XXX LIBSA_NO_FS_WRITE
  46  * XXX LIBSA_NO_FS_SYMLINK (does this even make sense?)
  47  * XXX LIBSA_FS_SINGLECOMPONENT (does this even make sense?)
  48  */
  49
  50 #include <sys/types.h>
  51 #include <sys/stat.h>
  52 #include <netinet/in.h>
  53 #include <netinet/udp.h>
  54 #include <netinet/in_systm.h>
  55 #include <lib/libkern/libkern.h>
  56
  57 #include "stand.h"
  58 #include "net.h"
  59
  60 #include "tftp.h"
  61
  62 extern struct in_addr servip;
  63
  64 static int      tftpport = 2000;
  65
  66 #define RSPACE 520              /* max data packet, rounded up */
  67
  68 struct tftp_handle {
  69         struct iodesc  *iodesc;
  70         int             currblock;      /* contents of lastdata */
  71         int             islastblock;    /* flag */
  72         int             validsize;
  73         int             off;
  74         const char     *path;   /* saved for re-requests */
  75         struct {
  76                 u_char header[UDP_TOTAL_HEADER_SIZE];
  77                 struct tftphdr t;
  78                 u_char space[RSPACE];
  79         } lastdata;
  80 };
  81
  82 static const int tftperrors[8] = {
  83         0,                      /* ??? */
  84         ENOENT,
  85         EPERM,
  86         ENOSPC,
  87         EINVAL,                 /* ??? */
  88         EINVAL,                 /* ??? */
  89         EEXIST,
  90         EINVAL,                 /* ??? */
  91 };
  92
  93 static ssize_t recvtftp(struct iodesc *, void *, size_t, saseconds_t);
  94 static int tftp_makereq(struct tftp_handle *);
  95 static int tftp_getnextblock(struct tftp_handle *);
  96 #ifndef TFTP_NOTERMINATE
  97 static void tftp_terminate(struct tftp_handle *);
  98 #endif
  99 static ssize_t tftp_size_of_file(struct tftp_handle *tftpfile);
 100
 101 static ssize_t
 102 recvtftp(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
 103 {
 104         ssize_t n;
 105         struct tftphdr *t;
 106
 107         errno = 0;
 108
 109         n = readudp(d, pkt, len, tleft);
 110
 111         if (n < 4)
 112                 return -1;
 113
 114         t = (struct tftphdr *)pkt;
 115         switch (ntohs(t->th_opcode)) {
 116         case DATA:
 117                 if (htons(t->th_block) != d->xid) {
 118                         /*
 119                          * Expected block?
 120                          */
 121                         return -1;
 122                 }
 123                 if (d->xid == 1) {
 124                         /*
 125                          * First data packet from new port.
 126                          */
 127                         struct udphdr *uh;
 128                         uh = (struct udphdr *)pkt - 1;
 129                         d->destport = uh->uh_sport;
 130                 } /* else check uh_sport has not changed??? */
 131                 return (n - (t->th_data - (char *)t));
 132         case ERROR:
 133                 if ((unsigned int)ntohs(t->th_code) >= 8) {
 134                         printf("illegal tftp error %d\n", ntohs(t->th_code));
 135                         errno = EIO;
 136                 } else {
 137 #ifdef DEBUG
 138                         printf("tftp-error %d\n", ntohs(t->th_code));
 139 #endif
 140                         errno = tftperrors[ntohs(t->th_code)];
 141                 }
 142                 return -1;
 143         default:
 144 #ifdef DEBUG
 145                 printf("tftp type %d not handled\n", ntohs(t->th_opcode));
 146 #endif
 147                 return -1;
 148         }
 149 }
 150
 151 /* send request, expect first block (or error) */
 152 static int
 153 tftp_makereq(struct tftp_handle *h)
 154 {
 155         struct {
 156                 u_char header[UDP_TOTAL_HEADER_SIZE];
 157                 struct tftphdr t;
 158                 u_char space[FNAME_SIZE + 6];
 159         } wbuf;
 160         char           *wtail;
 161         int             l;
 162         ssize_t         res;
 163         struct tftphdr *t;
 164
 165         wbuf.t.th_opcode = htons((u_short)RRQ);
 166         wtail = wbuf.t.th_stuff;
 167         l = strlen(h->path);
 168         (void)memcpy(wtail, h->path, l + 1);
 169         wtail += l + 1;
 170         (void)memcpy(wtail, "octet", 6);
 171         wtail += 6;
 172
 173         t = &h->lastdata.t;
 174
 175         /* h->iodesc->myport = htons(--tftpport); */
 176         h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff));
 177         h->iodesc->destport = htons(IPPORT_TFTP);
 178         h->iodesc->xid = 1;     /* expected block */
 179
 180         res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *)&wbuf.t,
 181                        recvtftp, t, sizeof(*t) + RSPACE);
 182
 183         if (res == -1)
 184                 return errno;
 185
 186         h->currblock = 1;
 187         h->validsize = res;
 188         h->islastblock = 0;
 189         if (res < SEGSIZE)
 190                 h->islastblock = 1;     /* very short file */
 191         return 0;
 192 }
 193
 194 /* ack block, expect next */
 195 static int
 196 tftp_getnextblock(struct tftp_handle *h)
 197 {
 198         struct {
 199                 u_char header[UDP_TOTAL_HEADER_SIZE];
 200                 struct tftphdr t;
 201         } wbuf;
 202         char           *wtail;
 203         int             res;
 204         struct tftphdr *t;
 205
 206         wbuf.t.th_opcode = htons((u_short)ACK);
 207         wbuf.t.th_block = htons((u_short)h->currblock);
 208         wtail = (char *)&wbuf.t.th_data;
 209
 210         t = &h->lastdata.t;
 211
 212         h->iodesc->xid = h->currblock + 1;      /* expected block */
 213
 214         res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *)&wbuf.t,
 215                        recvtftp, t, sizeof(*t) + RSPACE);
 216
 217         if (res == -1)          /* 0 is OK! */
 218                 return errno;
 219
 220         h->currblock++;
 221         h->validsize = res;
 222         if (res < SEGSIZE)
 223                 h->islastblock = 1;     /* EOF */
 224         return 0;
 225 }
 226
 227 #ifndef TFTP_NOTERMINATE
 228 static void
 229 tftp_terminate(struct tftp_handle *h)
 230 {
 231         struct {
 232                 u_char header[UDP_TOTAL_HEADER_SIZE];
 233                 struct tftphdr t;
 234         } wbuf;
 235         char           *wtail;
 236
 237         wtail = (char *)&wbuf.t.th_data;
 238         if (h->islastblock) {
 239                 wbuf.t.th_opcode = htons((u_short)ACK);
 240                 wbuf.t.th_block = htons((u_short)h->currblock);
 241         } else {
 242                 wbuf.t.th_opcode = htons((u_short)ERROR);
 243                 wbuf.t.th_code = htons((u_short)ENOSPACE); /* ??? */
 244                 *wtail++ = '\0'; /* empty error string */
 245         }
 246
 247         (void)sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t);
 248 }
 249 #endif
 250
 251 __compactcall int
 252 tftp_open(const char *path, struct open_file *f)
 253 {
 254         struct tftp_handle *tftpfile;
 255         struct iodesc  *io;
 256         int             res;
 257
 258         tftpfile = (struct tftp_handle *)alloc(sizeof(*tftpfile));
 259         if (!tftpfile)
 260                 return ENOMEM;
 261
 262         tftpfile->iodesc = io = socktodesc(*(int *)(f->f_devdata));
 263         io->destip = servip;
 264         tftpfile->off = 0;
 265         tftpfile->path = path;  /* XXXXXXX we hope it's static */
 266
 267         res = tftp_makereq(tftpfile);
 268
 269         if (res) {
 270                 dealloc(tftpfile, sizeof(*tftpfile));
 271                 return res;
 272         }
 273         f->f_fsdata = (void *)tftpfile;
 274         fsmod = "nfs";
 275         return 0;
 276 }
 277
 278 __compactcall int
 279 tftp_read(struct open_file *f, void *addr, size_t size, size_t *resid)
 280 {
 281         struct tftp_handle *tftpfile;
 282 #if !defined(LIBSA_NO_TWIDDLE)
 283         static int      tc = 0;
 284 #endif
 285         tftpfile = (struct tftp_handle *)f->f_fsdata;
 286
 287         while (size > 0) {
 288                 int needblock;
 289                 size_t count;
 290
 291 #if !defined(LIBSA_NO_TWIDDLE)
 292                 if (!(tc++ % 16))
 293                         twiddle();
 294 #endif
 295
 296                 needblock = tftpfile->off / SEGSIZE + 1;
 297
 298                 if (tftpfile->currblock > needblock) {  /* seek backwards */
 299 #ifndef TFTP_NOTERMINATE
 300                         tftp_terminate(tftpfile);
 301 #endif
 302                         tftp_makereq(tftpfile); /* no error check, it worked
 303                                                  * for open */
 304                 }
 305
 306                 while (tftpfile->currblock < needblock) {
 307                         int res;
 308
 309                         res = tftp_getnextblock(tftpfile);
 310                         if (res) {      /* no answer */
 311 #ifdef DEBUG
 312                                 printf("tftp: read error (block %d->%d)\n",
 313                                        tftpfile->currblock, needblock);
 314 #endif
 315                                 return res;
 316                         }
 317                         if (tftpfile->islastblock)
 318                                 break;
 319                 }
 320
 321                 if (tftpfile->currblock == needblock) {
 322                         size_t offinblock, inbuffer;
 323
 324                         offinblock = tftpfile->off % SEGSIZE;
 325
 326                         if (offinblock > tftpfile->validsize) {
 327 #ifdef DEBUG
 328                                 printf("tftp: invalid offset %d\n",
 329                                     tftpfile->off);
 330 #endif
 331                                 return EINVAL;
 332                         }
 333                         inbuffer = tftpfile->validsize - offinblock;
 334                         count = (size < inbuffer ? size : inbuffer);
 335                         (void)memcpy(addr,
 336                             tftpfile->lastdata.t.th_data + offinblock,
 337                             count);
 338
 339                         addr = (char *)addr + count;
 340                         tftpfile->off += count;
 341                         size -= count;
 342
 343                         if ((tftpfile->islastblock) && (count == inbuffer))
 344                                 break;  /* EOF */
 345                 } else {
 346 #ifdef DEBUG
 347                         printf("tftp: block %d not found\n", needblock);
 348 #endif
 349                         return EINVAL;
 350                 }
 351
 352         }
 353
 354         if (resid)
 355                 *resid = size;
 356         return 0;
 357 }
 358
 359 __compactcall int
 360 tftp_close(struct open_file *f)
 361 {
 362         struct tftp_handle *tftpfile;
 363         tftpfile = (struct tftp_handle *)f->f_fsdata;
 364
 365 #ifdef TFTP_NOTERMINATE
 366         /* let it time out ... */
 367 #else
 368         tftp_terminate(tftpfile);
 369 #endif
 370
 371         dealloc(tftpfile, sizeof(*tftpfile));
 372         return 0;
 373 }
 374
 375 __compactcall int
 376 tftp_write(struct open_file *f, void *start, size_t size, size_t *resid)
 377 {
 378
 379         return EROFS;
 380 }
 381
 382 static ssize_t
 383 tftp_size_of_file(struct tftp_handle *tftpfile)
 384 {
 385         ssize_t filesize;
 386
 387         if (tftpfile->currblock > 1) {  /* move to start of file */
 388 #ifndef TFTP_NOTERMINATE
 389                 tftp_terminate(tftpfile);
 390 #endif
 391                 tftp_makereq(tftpfile); /* no error check, it worked
 392                                          * for open */
 393         }
 394
 395         /* start with the size of block 1 */
 396         filesize = tftpfile->validsize;
 397
 398         /* and keep adding the sizes till we hit the last block */
 399         while (!tftpfile->islastblock) {
 400                 int res;
 401
 402                 res = tftp_getnextblock(tftpfile);
 403                 if (res) {      /* no answer */
 404 #ifdef DEBUG
 405                         printf("tftp: read error (block %d)\n",
 406                                         tftpfile->currblock);
 407 #endif
 408                         return -1;
 409                 }
 410                 filesize += tftpfile->validsize;
 411         }
 412 #ifdef DEBUG
 413         printf("tftp_size_of_file: file is %zu bytes\n", filesize);
 414 #endif
 415         return filesize;
 416 }
 417
 418 __compactcall int
 419 tftp_stat(struct open_file *f, struct stat *sb)
 420 {
 421         struct tftp_handle *tftpfile;
 422         tftpfile = (struct tftp_handle *)f->f_fsdata;
 423
 424         sb->st_mode = 0444;
 425         sb->st_nlink = 1;
 426         sb->st_uid = 0;
 427         sb->st_gid = 0;
 428         sb->st_size = tftp_size_of_file(tftpfile);
 429         return 0;
 430 }
 431
 432 #if defined(LIBSA_ENABLE_LS_OP)
 433 #include "ls.h"
 434 __compactcall void
 435 tftp_ls(struct open_file *f, const char *pattern)
 436 {
 437         lsunsup("tftp");
 438 }
 439 #endif
 440
 441 __compactcall off_t
 442 tftp_seek(struct open_file *f, off_t offset, int where)
 443 {
 444         struct tftp_handle *tftpfile;
 445         tftpfile = (struct tftp_handle *)f->f_fsdata;
 446
 447         switch (where) {
 448         case SEEK_SET:
 449                 tftpfile->off = offset;
 450                 break;
 451         case SEEK_CUR:
 452                 tftpfile->off += offset;
 453                 break;
 454         default:
 455                 errno = EOFFSET;
 456                 return -1;
 457         }
 458         return tftpfile->off;
 459 }