nbd.c

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include "nbd.h"
  21
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <sys/ioctl.h>
  25 #ifdef __sun__
  26 #include <sys/ioccom.h>
  27 #endif
  28 #include <ctype.h>
  29 #include <inttypes.h>
  30 #include <sys/socket.h>
  31 #include <sys/un.h>
  32 #include <netinet/in.h>
  33 #include <netinet/tcp.h>
  34 #include <arpa/inet.h>
  35 #include <netdb.h>
  36
  37 #if defined(QEMU_NBD)
  38 extern int verbose;
  39 #else
  40 static int verbose = 0;
  41 #endif
  42
  43 #define TRACE(msg, ...) do { \
  44     if (verbose) LOG(msg, ## __VA_ARGS__); \
  45 } while(0)
  46
  47 #define LOG(msg, ...) do { \
  48     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
  49             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
  50 } while(0)
  51
  52 /* This is all part of the "official" NBD API */
  53
  54 #define NBD_REQUEST_MAGIC       0x25609513
  55 #define NBD_REPLY_MAGIC         0x67446698
  56
  57 #define NBD_SET_SOCK            _IO(0xab, 0)
  58 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  59 #define NBD_SET_SIZE            _IO(0xab, 2)
  60 #define NBD_DO_IT               _IO(0xab, 3)
  61 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  62 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  63 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  64 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  65 #define NBD_DISCONNECT          _IO(0xab, 8)
  66
  67 /* That's all folks */
  68
  69 #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
  70 #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
  71
  72 size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
  73 {
  74     size_t offset = 0;
  75
  76     while (offset < size) {
  77         ssize_t len;
  78
  79         if (do_read) {
  80             len = read(fd, buffer + offset, size - offset);
  81         } else {
  82             len = write(fd, buffer + offset, size - offset);
  83         }
  84
  85         /* recoverable error */
  86         if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
  87             continue;
  88         }
  89
  90         /* eof */
  91         if (len == 0) {
  92             break;
  93         }
  94
  95         /* unrecoverable error */
  96         if (len == -1) {
  97             return 0;
  98         }
  99
 100         offset += len;
 101     }
 102
 103     return offset;
 104 }
 105
 106 int tcp_socket_outgoing(const char *address, uint16_t port)
 107 {
 108     int s;
 109     struct in_addr in;
 110     struct sockaddr_in addr;
 111     int serrno;
 112
 113     s = socket(PF_INET, SOCK_STREAM, 0);
 114     if (s == -1) {
 115         return -1;
 116     }
 117
 118     if (inet_aton(address, &in) == 0) {
 119         struct hostent *ent;
 120
 121         ent = gethostbyname(address);
 122         if (ent == NULL) {
 123             goto error;
 124         }
 125
 126         memcpy(&in, ent->h_addr, sizeof(in));
 127     }
 128
 129     addr.sin_family = AF_INET;
 130     addr.sin_port = htons(port);
 131     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
 132
 133     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 134         goto error;
 135     }
 136
 137     return s;
 138 error:
 139     serrno = errno;
 140     close(s);
 141     errno = serrno;
 142     return -1;
 143 }
 144
 145 int tcp_socket_incoming(const char *address, uint16_t port)
 146 {
 147     int s;
 148     struct in_addr in;
 149     struct sockaddr_in addr;
 150     int serrno;
 151     int opt;
 152
 153     s = socket(PF_INET, SOCK_STREAM, 0);
 154     if (s == -1) {
 155         return -1;
 156     }
 157
 158     if (inet_aton(address, &in) == 0) {
 159         struct hostent *ent;
 160
 161         ent = gethostbyname(address);
 162         if (ent == NULL) {
 163             goto error;
 164         }
 165
 166         memcpy(&in, ent->h_addr, sizeof(in));
 167     }
 168
 169     addr.sin_family = AF_INET;
 170     addr.sin_port = htons(port);
 171     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
 172
 173     opt = 1;
 174     if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1) {
 175         goto error;
 176     }
 177
 178     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 179         goto error;
 180     }
 181
 182     if (listen(s, 128) == -1) {
 183         goto error;
 184     }
 185
 186     return s;
 187 error:
 188     serrno = errno;
 189     close(s);
 190     errno = serrno;
 191     return -1;
 192 }
 193
 194 int unix_socket_incoming(const char *path)
 195 {
 196     int s;
 197     struct sockaddr_un addr;
 198     int serrno;
 199
 200     s = socket(PF_UNIX, SOCK_STREAM, 0);
 201     if (s == -1) {
 202         return -1;
 203     }
 204
 205     memset(&addr, 0, sizeof(addr));
 206     addr.sun_family = AF_UNIX;
 207     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 208
 209     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 210         goto error;
 211     }
 212
 213     if (listen(s, 128) == -1) {
 214         goto error;
 215     }
 216
 217     return s;
 218 error:
 219     serrno = errno;
 220     close(s);
 221     errno = serrno;
 222     return -1;
 223 }
 224
 225 int unix_socket_outgoing(const char *path)
 226 {
 227     int s;
 228     struct sockaddr_un addr;
 229     int serrno;
 230
 231     s = socket(PF_UNIX, SOCK_STREAM, 0);
 232     if (s == -1) {
 233         return -1;
 234     }
 235
 236     memset(&addr, 0, sizeof(addr));
 237     addr.sun_family = AF_UNIX;
 238     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 239
 240     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 241         goto error;
 242     }
 243
 244     return s;
 245 error:
 246     serrno = errno;
 247     close(s);
 248     errno = serrno;
 249     return -1;
 250 }
 251
 252
 253 /* Basic flow
 254
 255    Server         Client
 256
 257    Negotiate
 258                   Request
 259    Response
 260                   Request
 261    Response
 262                   ...
 263    ...
 264                   Request (type == 2)
 265 */
 266
 267 int nbd_negotiate(int csock, off_t size)
 268 {
 269         char buf[8 + 8 + 8 + 128];
 270
 271         /* Negotiate
 272            [ 0 ..   7]   passwd   ("NBDMAGIC")
 273            [ 8 ..  15]   magic    (0x00420281861253)
 274            [16 ..  23]   size
 275            [24 .. 151]   reserved (0)
 276          */
 277
 278         TRACE("Beginning negotiation.");
 279         memcpy(buf, "NBDMAGIC", 8);
 280         cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
 281         cpu_to_be64w((uint64_t*)(buf + 16), size);
 282         memset(buf + 24, 0, 128);
 283
 284         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 285                 LOG("write failed");
 286                 errno = EINVAL;
 287                 return -1;
 288         }
 289
 290         TRACE("Negotation succeeded.");
 291
 292         return 0;
 293 }
 294
 295 int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
 296 {
 297         char buf[8 + 8 + 8 + 128];
 298         uint64_t magic;
 299
 300         TRACE("Receiving negotation.");
 301
 302         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 303                 LOG("read failed");
 304                 errno = EINVAL;
 305                 return -1;
 306         }
 307
 308         magic = be64_to_cpup((uint64_t*)(buf + 8));
 309         *size = be64_to_cpup((uint64_t*)(buf + 16));
 310         *blocksize = 1024;
 311
 312         TRACE("Magic is %c%c%c%c%c%c%c%c",
 313               isprint(buf[0]) ? buf[0] : '.',
 314               isprint(buf[1]) ? buf[1] : '.',
 315               isprint(buf[2]) ? buf[2] : '.',
 316               isprint(buf[3]) ? buf[3] : '.',
 317               isprint(buf[4]) ? buf[4] : '.',
 318               isprint(buf[5]) ? buf[5] : '.',
 319               isprint(buf[6]) ? buf[6] : '.',
 320               isprint(buf[7]) ? buf[7] : '.');
 321         TRACE("Magic is 0x%" PRIx64, magic);
 322         TRACE("Size is %" PRIu64, *size);
 323
 324         if (memcmp(buf, "NBDMAGIC", 8) != 0) {
 325                 LOG("Invalid magic received");
 326                 errno = EINVAL;
 327                 return -1;
 328         }
 329
 330         TRACE("Checking magic");
 331
 332         if (magic != 0x00420281861253LL) {
 333                 LOG("Bad magic received");
 334                 errno = EINVAL;
 335                 return -1;
 336         }
 337         return 0;
 338 }
 339
 340 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
 341 {
 342         TRACE("Setting block size to %lu", (unsigned long)blocksize);
 343
 344         if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
 345                 int serrno = errno;
 346                 LOG("Failed setting NBD block size");
 347                 errno = serrno;
 348                 return -1;
 349         }
 350
 351         TRACE("Setting size to %llu block(s)",
 352               (unsigned long long)(size / blocksize));
 353
 354         if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
 355                 int serrno = errno;
 356                 LOG("Failed setting size (in blocks)");
 357                 errno = serrno;
 358                 return -1;
 359         }
 360
 361         TRACE("Clearing NBD socket");
 362
 363         if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
 364                 int serrno = errno;
 365                 LOG("Failed clearing NBD socket");
 366                 errno = serrno;
 367                 return -1;
 368         }
 369
 370         TRACE("Setting NBD socket");
 371
 372         if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
 373                 int serrno = errno;
 374                 LOG("Failed to set NBD socket");
 375                 errno = serrno;
 376                 return -1;
 377         }
 378
 379         TRACE("Negotiation ended");
 380
 381         return 0;
 382 }
 383
 384 int nbd_disconnect(int fd)
 385 {
 386         ioctl(fd, NBD_CLEAR_QUE);
 387         ioctl(fd, NBD_DISCONNECT);
 388         ioctl(fd, NBD_CLEAR_SOCK);
 389         return 0;
 390 }
 391
 392 int nbd_client(int fd, int csock)
 393 {
 394         int ret;
 395         int serrno;
 396
 397         TRACE("Doing NBD loop");
 398
 399         ret = ioctl(fd, NBD_DO_IT);
 400         serrno = errno;
 401
 402         TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
 403
 404         TRACE("Clearing NBD queue");
 405         ioctl(fd, NBD_CLEAR_QUE);
 406
 407         TRACE("Clearing NBD socket");
 408         ioctl(fd, NBD_CLEAR_SOCK);
 409
 410         errno = serrno;
 411         return ret;
 412 }
 413
 414 int nbd_send_request(int csock, struct nbd_request *request)
 415 {
 416         uint8_t buf[4 + 4 + 8 + 8 + 4];
 417
 418         cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
 419         cpu_to_be32w((uint32_t*)(buf + 4), request->type);
 420         cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
 421         cpu_to_be64w((uint64_t*)(buf + 16), request->from);
 422         cpu_to_be32w((uint32_t*)(buf + 24), request->len);
 423
 424         TRACE("Sending request to client");
 425
 426         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 427                 LOG("writing to socket failed");
 428                 errno = EINVAL;
 429                 return -1;
 430         }
 431         return 0;
 432 }
 433
 434
 435 static int nbd_receive_request(int csock, struct nbd_request *request)
 436 {
 437         uint8_t buf[4 + 4 + 8 + 8 + 4];
 438         uint32_t magic;
 439
 440         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 441                 LOG("read failed");
 442                 errno = EINVAL;
 443                 return -1;
 444         }
 445
 446         /* Request
 447            [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 448            [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
 449            [ 8 .. 15]   handle
 450            [16 .. 23]   from
 451            [24 .. 27]   len
 452          */
 453
 454         magic = be32_to_cpup((uint32_t*)buf);
 455         request->type  = be32_to_cpup((uint32_t*)(buf + 4));
 456         request->handle = be64_to_cpup((uint64_t*)(buf + 8));
 457         request->from  = be64_to_cpup((uint64_t*)(buf + 16));
 458         request->len   = be32_to_cpup((uint32_t*)(buf + 24));
 459
 460         TRACE("Got request: "
 461               "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
 462               magic, request->type, request->from, request->len);
 463
 464         if (magic != NBD_REQUEST_MAGIC) {
 465                 LOG("invalid magic (got 0x%x)", magic);
 466                 errno = EINVAL;
 467                 return -1;
 468         }
 469         return 0;
 470 }
 471
 472 int nbd_receive_reply(int csock, struct nbd_reply *reply)
 473 {
 474         uint8_t buf[4 + 4 + 8];
 475         uint32_t magic;
 476
 477         memset(buf, 0xAA, sizeof(buf));
 478
 479         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 480                 LOG("read failed");
 481                 errno = EINVAL;
 482                 return -1;
 483         }
 484
 485         /* Reply
 486            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 487            [ 4 ..  7]    error   (0 == no error)
 488            [ 7 .. 15]    handle
 489          */
 490
 491         magic = be32_to_cpup((uint32_t*)buf);
 492         reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
 493         reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
 494
 495         TRACE("Got reply: "
 496               "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
 497               magic, reply->error, reply->handle);
 498
 499         if (magic != NBD_REPLY_MAGIC) {
 500                 LOG("invalid magic (got 0x%x)", magic);
 501                 errno = EINVAL;
 502                 return -1;
 503         }
 504         return 0;
 505 }
 506
 507 static int nbd_send_reply(int csock, struct nbd_reply *reply)
 508 {
 509         uint8_t buf[4 + 4 + 8];
 510
 511         /* Reply
 512            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 513            [ 4 ..  7]    error   (0 == no error)
 514            [ 7 .. 15]    handle
 515          */
 516         cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
 517         cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
 518         cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
 519
 520         TRACE("Sending response to client");
 521
 522         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 523                 LOG("writing to socket failed");
 524                 errno = EINVAL;
 525                 return -1;
 526         }
 527         return 0;
 528 }
 529
 530 int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
 531              off_t *offset, bool readonly, uint8_t *data, int data_size)
 532 {
 533         struct nbd_request request;
 534         struct nbd_reply reply;
 535
 536         TRACE("Reading request.");
 537
 538         if (nbd_receive_request(csock, &request) == -1)
 539                 return -1;
 540
 541         if (request.len > data_size) {
 542                 LOG("len (%u) is larger than max len (%u)",
 543                     request.len, data_size);
 544                 errno = EINVAL;
 545                 return -1;
 546         }
 547
 548         if ((request.from + request.len) < request.from) {
 549                 LOG("integer overflow detected! "
 550                     "you're probably being attacked");
 551                 errno = EINVAL;
 552                 return -1;
 553         }
 554
 555         if ((request.from + request.len) > size) {
 556                 LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
 557                     ", Offset: %" PRIu64 "\n",
 558                      request.from, request.len, size, dev_offset);
 559                 LOG("requested operation past EOF--bad client?");
 560                 errno = EINVAL;
 561                 return -1;
 562         }
 563
 564         TRACE("Decoding type");
 565
 566         reply.handle = request.handle;
 567         reply.error = 0;
 568
 569         switch (request.type) {
 570         case NBD_CMD_READ:
 571                 TRACE("Request type is READ");
 572
 573                 if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
 574                               request.len / 512) == -1) {
 575                         LOG("reading from file failed");
 576                         errno = EINVAL;
 577                         return -1;
 578                 }
 579                 *offset += request.len;
 580
 581                 TRACE("Read %u byte(s)", request.len);
 582
 583                 if (nbd_send_reply(csock, &reply) == -1)
 584                         return -1;
 585
 586                 TRACE("Sending data to client");
 587
 588                 if (write_sync(csock, data, request.len) != request.len) {
 589                         LOG("writing to socket failed");
 590                         errno = EINVAL;
 591                         return -1;
 592                 }
 593                 break;
 594         case NBD_CMD_WRITE:
 595                 TRACE("Request type is WRITE");
 596
 597                 TRACE("Reading %u byte(s)", request.len);
 598
 599                 if (read_sync(csock, data, request.len) != request.len) {
 600                         LOG("reading from socket failed");
 601                         errno = EINVAL;
 602                         return -1;
 603                 }
 604
 605                 if (readonly) {
 606                         TRACE("Server is read-only, return error");
 607                         reply.error = 1;
 608                 } else {
 609                         TRACE("Writing to device");
 610
 611                         if (bdrv_write(bs, (request.from + dev_offset) / 512,
 612                                        data, request.len / 512) == -1) {
 613                                 LOG("writing to file failed");
 614                                 errno = EINVAL;
 615                                 return -1;
 616                         }
 617
 618                         *offset += request.len;
 619                 }
 620
 621                 if (nbd_send_reply(csock, &reply) == -1)
 622                         return -1;
 623                 break;
 624         case NBD_CMD_DISC:
 625                 TRACE("Request type is DISCONNECT");
 626                 errno = 0;
 627                 return 1;
 628         default:
 629                 LOG("invalid request type (%u) received", request.type);
 630                 errno = EINVAL;
 631                 return -1;
 632         }
 633
 634         TRACE("Request/Reply complete");
 635
 636         return 0;
 637 }