lib/libstand/tftp.c

   1 /*      $NetBSD: tftp.c,v 1.4 1997/09/17 16:57:07 drochner 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  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed for the NetBSD Project
  18  *      by Matthias Drochner.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libstand/tftp.c,v 1.2.6.4 2001/07/14 14:00:03 mikeh Exp $
  34  * $DragonFly: src/lib/libstand/tftp.c,v 1.5 2005/12/11 02:27:26 swildner Exp $
  35  */
  36
  37 /*
  38  * Simple TFTP implementation for libsa.
  39  * Assumes:
  40  *  - socket descriptor (int) at open_file->f_devdata
  41  *  - server host IP in global servip
  42  * Restrictions:
  43  *  - read only
  44  *  - lseek only with SEEK_SET or SEEK_CUR
  45  *  - no big time differences between transfers (<tftp timeout)
  46  */
  47
  48 #include <sys/param.h>
  49 #include <sys/stat.h>
  50 #include <netinet/in.h>
  51 #include <netinet/udp.h>
  52 #include <netinet/ip.h>
  53 #include <netinet/in_systm.h>
  54 #include <arpa/tftp.h>
  55
  56 #include <string.h>
  57
  58 #include "stand.h"
  59 #include "net.h"
  60 #include "netif.h"
  61
  62 #include "tftp.h"
  63
  64 static int      tftp_open(const char *path, struct open_file *f);
  65 static int      tftp_close(struct open_file *f);
  66 static int      tftp_read(struct open_file *f, void *buf, size_t size, size_t *resid);
  67 static int      tftp_write(struct open_file *f, void *buf, size_t size, size_t *resid);
  68 static off_t    tftp_seek(struct open_file *f, off_t offset, int where);
  69 static int      tftp_stat(struct open_file *f, struct stat *sb);
  70
  71 struct fs_ops tftp_fsops = {
  72         "tftp",
  73         tftp_open,
  74         tftp_close,
  75         tftp_read,
  76         tftp_write,
  77         tftp_seek,
  78         tftp_stat,
  79         null_readdir
  80 };
  81
  82 extern struct in_addr servip;
  83
  84 static int      tftpport = 2000;
  85
  86 #define RSPACE 520              /* max data packet, rounded up */
  87
  88 struct tftp_handle {
  89         struct iodesc  *iodesc;
  90         int             currblock;      /* contents of lastdata */
  91         int             islastblock;    /* flag */
  92         int             validsize;
  93         int             off;
  94         char           *path;   /* saved for re-requests */
  95         struct {
  96                 u_char header[HEADER_SIZE];
  97                 struct tftphdr t;
  98                 u_char space[RSPACE];
  99         } __packed __aligned(4) lastdata;
 100 };
 101
 102 static int tftperrors[8] = {
 103         0,                      /* ??? */
 104         ENOENT,
 105         EPERM,
 106         ENOSPC,
 107         EINVAL,                 /* ??? */
 108         EINVAL,                 /* ??? */
 109         EEXIST,
 110         EINVAL                  /* ??? */
 111 };
 112
 113 static ssize_t
 114 recvtftp(struct iodesc *d, void *pkt, size_t max_len, time_t tleft)
 115 {
 116         struct tftphdr *t;
 117         ssize_t len;
 118         ssize_t tmp_len;
 119
 120         /*
 121          * Note: errno of 0 with -1 return means udp poll failed or
 122          * packet was not for us.
 123          *
 124          * We may end up broadcasting the initial TFTP request.  Take the
 125          * first DATA result and save any ERROR result in case we do not
 126          * get a DATA.
 127          */
 128         errno = 0;
 129         bzero(pkt, len);
 130         if (d->xid == 1) {
 131                 len = -1;
 132                 while ((tmp_len = readudp(d, pkt, max_len, tleft)) > 0) {
 133                         len = tmp_len;
 134                         t = (struct tftphdr *)pkt;
 135                         if (ntohs(t->th_opcode) == DATA)
 136                                 break;
 137                 }
 138         } else {
 139                 len = readudp(d, pkt, max_len, tleft);
 140         }
 141         if ((int)len < (int)sizeof(*t))
 142                 return (-1);
 143         t = (struct tftphdr *)pkt;
 144         errno = 0;
 145
 146         switch (ntohs(t->th_opcode)) {
 147         case DATA: {
 148                 int got;
 149
 150                 if (htons(t->th_block) != d->xid) {
 151                         /*
 152                          * Expected block?
 153                          */
 154                         return (-1);
 155                 }
 156                 if (d->xid == 1) {
 157                         /*
 158                          * First data packet from new port.  Set destip in
 159                          * case we got replies from multiple hosts, so only
 160                          * one host is selected.
 161                          */
 162                         struct udphdr *uh;
 163                         struct ip *ip;
 164
 165                         uh = (struct udphdr *) pkt - 1;
 166                         ip = (struct ip *)uh - 1;
 167                         d->destport = uh->uh_sport;
 168                         d->destip = ip->ip_src;
 169                 } /* else check uh_sport has not changed??? */
 170                 got = len - (t->th_data - (char *)t);
 171                 return got;
 172         }
 173         case ERROR:
 174                 if ((unsigned) ntohs(t->th_code) >= 8) {
 175                         printf("illegal tftp error %d\n", ntohs(t->th_code));
 176                         errno = EIO;
 177                 } else {
 178 #ifdef DEBUG
 179                         printf("tftp-error %d\n", ntohs(t->th_code));
 180 #endif
 181                         errno = tftperrors[ntohs(t->th_code)];
 182                 }
 183                 return (-1);
 184         default:
 185 #ifdef DEBUG
 186                 printf("tftp type %d not handled\n", ntohs(t->th_opcode));
 187 #endif
 188                 return (-1);
 189         }
 190 }
 191
 192 /* send request, expect first block (or error) */
 193 static int
 194 tftp_makereq(struct tftp_handle *h)
 195 {
 196         struct {
 197                 u_char header[HEADER_SIZE];
 198                 struct tftphdr  t;
 199                 u_char space[FNAME_SIZE + 6];
 200         } __packed __aligned(4) wbuf;
 201         char           *wtail;
 202         int             l;
 203         ssize_t         res;
 204         struct tftphdr *t;
 205
 206         wbuf.t.th_opcode = htons((u_short) RRQ);
 207         wtail = wbuf.t.th_stuff;
 208         l = strlen(h->path);
 209         bcopy(h->path, wtail, l + 1);
 210         wtail += l + 1;
 211         bcopy("octet", wtail, 6);
 212         wtail += 6;
 213
 214         t = &h->lastdata.t;
 215
 216         /* h->iodesc->myport = htons(--tftpport); */
 217         h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff));
 218         h->iodesc->destport = htons(IPPORT_TFTP);
 219         h->iodesc->xid = 1;     /* expected block */
 220
 221         res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
 222                        recvtftp, t, sizeof(*t) + RSPACE);
 223
 224         if (res == -1)
 225                 return (errno);
 226
 227         h->currblock = 1;
 228         h->validsize = res;
 229         h->islastblock = 0;
 230         if (res < SEGSIZE)
 231                 h->islastblock = 1;     /* very short file */
 232         return (0);
 233 }
 234
 235 /* ack block, expect next */
 236 static int
 237 tftp_getnextblock(struct tftp_handle *h)
 238 {
 239         struct {
 240                 u_char header[HEADER_SIZE];
 241                 struct tftphdr t;
 242         } __packed __aligned(4) wbuf;
 243         char           *wtail;
 244         int             res;
 245         struct tftphdr *t;
 246
 247         /*
 248          * Ack previous block
 249          */
 250         wbuf.t.th_opcode = htons((u_short) ACK);
 251         wtail = (char *) &wbuf.t.th_block;
 252         wbuf.t.th_block = htons((u_short) h->currblock);
 253         wtail += 2;
 254
 255         t = &h->lastdata.t;
 256
 257         h->iodesc->xid = h->currblock + 1;      /* expected block */
 258
 259         res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
 260                        recvtftp, t, sizeof(*t) + RSPACE);
 261
 262         if (res == -1)          /* 0 is OK! */
 263                 return (errno);
 264
 265         h->currblock++;
 266         h->validsize = res;
 267         if (res < SEGSIZE)
 268                 h->islastblock = 1;     /* EOF */
 269         return (0);
 270 }
 271
 272 static int
 273 tftp_open(const char *path, struct open_file *f)
 274 {
 275         struct tftp_handle *tftpfile;
 276         struct iodesc  *io;
 277         int             res;
 278
 279         tftpfile = (struct tftp_handle *) malloc(sizeof(*tftpfile));
 280         if (!tftpfile)
 281                 return (ENOMEM);
 282
 283         tftpfile->iodesc = io = socktodesc(*(int *) (f->f_devdata));
 284         if (io == NULL)
 285                 return (EINVAL);
 286
 287         io->destip = servip;
 288         tftpfile->off = 0;
 289         tftpfile->path = strdup(path);
 290         if (tftpfile->path == NULL) {
 291             free(tftpfile);
 292             return(ENOMEM);
 293         }
 294
 295         res = tftp_makereq(tftpfile);
 296
 297         if (res) {
 298                 free(tftpfile->path);
 299                 free(tftpfile);
 300                 return (res);
 301         }
 302         f->f_fsdata = (void *) tftpfile;
 303         return (0);
 304 }
 305
 306 /*
 307  * Parameters:
 308  *      resid:  out
 309  */
 310 static int
 311 tftp_read(struct open_file *f, void *addr, size_t size, size_t *resid)
 312 {
 313         struct tftp_handle *tftpfile;
 314         static int      tc = 0;
 315         tftpfile = (struct tftp_handle *) f->f_fsdata;
 316
 317         while (size > 0) {
 318                 int needblock, count;
 319
 320                 if (!(tc++ % 16))
 321                         twiddle();
 322
 323                 needblock = tftpfile->off / SEGSIZE + 1;
 324
 325                 if (tftpfile->currblock > needblock)    /* seek backwards */
 326                         tftp_makereq(tftpfile); /* no error check, it worked
 327                                                  * for open */
 328
 329                 while (tftpfile->currblock < needblock) {
 330                         int res;
 331
 332                         res = tftp_getnextblock(tftpfile);
 333                         if (res) {      /* no answer */
 334 #ifdef DEBUG
 335                                 printf("tftp: read error\n");
 336 #endif
 337                                 return (res);
 338                         }
 339                         if (tftpfile->islastblock)
 340                                 break;
 341                 }
 342
 343                 if (tftpfile->currblock == needblock) {
 344                         int offinblock, inbuffer;
 345
 346                         offinblock = tftpfile->off % SEGSIZE;
 347
 348                         inbuffer = tftpfile->validsize - offinblock;
 349                         if (inbuffer < 0) {
 350 #ifdef DEBUG
 351                                 printf("tftp: invalid offset %d\n",
 352                                     tftpfile->off);
 353 #endif
 354                                 return (EINVAL);
 355                         }
 356                         count = (size < inbuffer ? size : inbuffer);
 357                         bcopy(tftpfile->lastdata.t.th_data + offinblock,
 358                               addr, count);
 359
 360                         addr = (char *)addr + count;
 361                         tftpfile->off += count;
 362                         size -= count;
 363
 364                         if ((tftpfile->islastblock) && (count == inbuffer))
 365                                 break;  /* EOF */
 366                 } else {
 367 #ifdef DEBUG
 368                         printf("tftp: block %d not found\n", needblock);
 369 #endif
 370                         return (EINVAL);
 371                 }
 372
 373         }
 374
 375         if (resid)
 376                 *resid = size;
 377         return (0);
 378 }
 379
 380 static int
 381 tftp_close(struct open_file *f)
 382 {
 383         struct tftp_handle *tftpfile;
 384         tftpfile = (struct tftp_handle *) f->f_fsdata;
 385
 386         /* let it time out ... */
 387         f->f_fsdata = NULL;
 388         if (tftpfile) {
 389                 free(tftpfile->path);
 390                 free(tftpfile);
 391                 f->f_fsdata = NULL;
 392         }
 393         return (0);
 394 }
 395
 396 /*
 397  * Parameters:
 398  *      resid:  out
 399  */
 400 static int
 401 tftp_write(struct open_file *f, void *start, size_t size, size_t *resid)
 402 {
 403         return (EROFS);
 404 }
 405
 406 static int
 407 tftp_stat(struct open_file *f, struct stat *sb)
 408 {
 409         struct tftp_handle *tftpfile;
 410         tftpfile = (struct tftp_handle *) f->f_fsdata;
 411
 412         sb->st_mode = 0444 | S_IFREG;
 413         sb->st_nlink = 1;
 414         sb->st_uid = 0;
 415         sb->st_gid = 0;
 416         sb->st_size = -1;
 417         return (0);
 418 }
 419
 420 static off_t
 421 tftp_seek(struct open_file *f, off_t offset, int where)
 422 {
 423         struct tftp_handle *tftpfile;
 424         tftpfile = (struct tftp_handle *) f->f_fsdata;
 425
 426         switch (where) {
 427         case SEEK_SET:
 428                 tftpfile->off = offset;
 429                 break;
 430         case SEEK_CUR:
 431                 tftpfile->off += offset;
 432                 break;
 433         default:
 434                 errno = EOFFSET;
 435                 return (-1);
 436         }
 437         return (tftpfile->off);
 438 }