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, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "nbd.h"
  20
  21 #include <errno.h>
  22 #include <string.h>
  23 #ifndef _WIN32
  24 #include <sys/ioctl.h>
  25 #endif
  26 #ifdef __sun__
  27 #include <sys/ioccom.h>
  28 #endif
  29 #include <ctype.h>
  30 #include <inttypes.h>
  31
  32 #include "qemu_socket.h"
  33
  34 //#define DEBUG_NBD
  35
  36 #ifdef DEBUG_NBD
  37 #define TRACE(msg, ...) do { \
  38     LOG(msg, ## __VA_ARGS__); \
  39 } while(0)
  40 #else
  41 #define TRACE(msg, ...) \
  42     do { } while (0)
  43 #endif
  44
  45 #define LOG(msg, ...) do { \
  46     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
  47             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
  48 } while(0)
  49
  50 /* This is all part of the "official" NBD API */
  51
  52 #define NBD_REQUEST_MAGIC       0x25609513
  53 #define NBD_REPLY_MAGIC         0x67446698
  54
  55 #define NBD_SET_SOCK            _IO(0xab, 0)
  56 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  57 #define NBD_SET_SIZE            _IO(0xab, 2)
  58 #define NBD_DO_IT               _IO(0xab, 3)
  59 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  60 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  61 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  62 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  63 #define NBD_DISCONNECT          _IO(0xab, 8)
  64
  65 /* That's all folks */
  66
  67 #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
  68 #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
  69
  70 size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
  71 {
  72     size_t offset = 0;
  73
  74     while (offset < size) {
  75         ssize_t len;
  76
  77         if (do_read) {
  78             len = recv(fd, buffer + offset, size - offset, 0);
  79         } else {
  80             len = send(fd, buffer + offset, size - offset, 0);
  81         }
  82
  83         if (len == -1)
  84             errno = socket_error();
  85
  86         /* recoverable error */
  87         if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
  88             continue;
  89         }
  90
  91         /* eof */
  92         if (len == 0) {
  93             break;
  94         }
  95
  96         /* unrecoverable error */
  97         if (len == -1) {
  98             return 0;
  99         }
 100
 101         offset += len;
 102     }
 103
 104     return offset;
 105 }
 106
 107 int tcp_socket_outgoing(const char *address, uint16_t port)
 108 {
 109     int s;
 110     struct in_addr in;
 111     struct sockaddr_in addr;
 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     closesocket(s);
 140     return -1;
 141 }
 142
 143 int tcp_socket_incoming(const char *address, uint16_t port)
 144 {
 145     int s;
 146     struct in_addr in;
 147     struct sockaddr_in addr;
 148     int opt;
 149
 150     s = socket(PF_INET, SOCK_STREAM, 0);
 151     if (s == -1) {
 152         return -1;
 153     }
 154
 155     if (inet_aton(address, &in) == 0) {
 156         struct hostent *ent;
 157
 158         ent = gethostbyname(address);
 159         if (ent == NULL) {
 160             goto error;
 161         }
 162
 163         memcpy(&in, ent->h_addr, sizeof(in));
 164     }
 165
 166     addr.sin_family = AF_INET;
 167     addr.sin_port = htons(port);
 168     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
 169
 170     opt = 1;
 171     if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
 172                    (const void *) &opt, sizeof(opt)) == -1) {
 173         goto error;
 174     }
 175
 176     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 177         goto error;
 178     }
 179
 180     if (listen(s, 128) == -1) {
 181         goto error;
 182     }
 183
 184     return s;
 185 error:
 186     closesocket(s);
 187     return -1;
 188 }
 189
 190 #ifndef _WIN32
 191 int unix_socket_incoming(const char *path)
 192 {
 193     int s;
 194     struct sockaddr_un addr;
 195
 196     s = socket(PF_UNIX, SOCK_STREAM, 0);
 197     if (s == -1) {
 198         return -1;
 199     }
 200
 201     memset(&addr, 0, sizeof(addr));
 202     addr.sun_family = AF_UNIX;
 203     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 204
 205     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 206         goto error;
 207     }
 208
 209     if (listen(s, 128) == -1) {
 210         goto error;
 211     }
 212
 213     return s;
 214 error:
 215     closesocket(s);
 216     return -1;
 217 }
 218
 219 int unix_socket_outgoing(const char *path)
 220 {
 221     int s;
 222     struct sockaddr_un addr;
 223
 224     s = socket(PF_UNIX, SOCK_STREAM, 0);
 225     if (s == -1) {
 226         return -1;
 227     }
 228
 229     memset(&addr, 0, sizeof(addr));
 230     addr.sun_family = AF_UNIX;
 231     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 232
 233     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 234         goto error;
 235     }
 236
 237     return s;
 238 error:
 239     closesocket(s);
 240     return -1;
 241 }
 242 #else
 243 int unix_socket_incoming(const char *path)
 244 {
 245     errno = ENOTSUP;
 246     return -1;
 247 }
 248
 249 int unix_socket_outgoing(const char *path)
 250 {
 251     errno = ENOTSUP;
 252     return -1;
 253 }
 254 #endif
 255
 256
 257 /* Basic flow
 258
 259    Server         Client
 260
 261    Negotiate
 262                   Request
 263    Response
 264                   Request
 265    Response
 266                   ...
 267    ...
 268                   Request (type == 2)
 269 */
 270
 271 int nbd_negotiate(int csock, off_t size)
 272 {
 273         char buf[8 + 8 + 8 + 128];
 274
 275         /* Negotiate
 276            [ 0 ..   7]   passwd   ("NBDMAGIC")
 277            [ 8 ..  15]   magic    (0x00420281861253)
 278            [16 ..  23]   size
 279            [24 .. 151]   reserved (0)
 280          */
 281
 282         TRACE("Beginning negotiation.");
 283         memcpy(buf, "NBDMAGIC", 8);
 284         cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
 285         cpu_to_be64w((uint64_t*)(buf + 16), size);
 286         memset(buf + 24, 0, 128);
 287
 288         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 289                 LOG("write failed");
 290                 errno = EINVAL;
 291                 return -1;
 292         }
 293
 294         TRACE("Negotation succeeded.");
 295
 296         return 0;
 297 }
 298
 299 int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
 300 {
 301         char buf[8 + 8 + 8 + 128];
 302         uint64_t magic;
 303
 304         TRACE("Receiving negotation.");
 305
 306         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 307                 LOG("read failed");
 308                 errno = EINVAL;
 309                 return -1;
 310         }
 311
 312         magic = be64_to_cpup((uint64_t*)(buf + 8));
 313         *size = be64_to_cpup((uint64_t*)(buf + 16));
 314         *blocksize = 1024;
 315
 316         TRACE("Magic is %c%c%c%c%c%c%c%c",
 317               qemu_isprint(buf[0]) ? buf[0] : '.',
 318               qemu_isprint(buf[1]) ? buf[1] : '.',
 319               qemu_isprint(buf[2]) ? buf[2] : '.',
 320               qemu_isprint(buf[3]) ? buf[3] : '.',
 321               qemu_isprint(buf[4]) ? buf[4] : '.',
 322               qemu_isprint(buf[5]) ? buf[5] : '.',
 323               qemu_isprint(buf[6]) ? buf[6] : '.',
 324               qemu_isprint(buf[7]) ? buf[7] : '.');
 325         TRACE("Magic is 0x%" PRIx64, magic);
 326         TRACE("Size is %" PRIu64, *size);
 327
 328         if (memcmp(buf, "NBDMAGIC", 8) != 0) {
 329                 LOG("Invalid magic received");
 330                 errno = EINVAL;
 331                 return -1;
 332         }
 333
 334         TRACE("Checking magic");
 335
 336         if (magic != 0x00420281861253LL) {
 337                 LOG("Bad magic received");
 338                 errno = EINVAL;
 339                 return -1;
 340         }
 341         return 0;
 342 }
 343
 344 #ifndef _WIN32
 345 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
 346 {
 347         TRACE("Setting block size to %lu", (unsigned long)blocksize);
 348
 349         if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
 350                 int serrno = errno;
 351                 LOG("Failed setting NBD block size");
 352                 errno = serrno;
 353                 return -1;
 354         }
 355
 356         TRACE("Setting size to %llu block(s)",
 357               (unsigned long long)(size / blocksize));
 358
 359         if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
 360                 int serrno = errno;
 361                 LOG("Failed setting size (in blocks)");
 362                 errno = serrno;
 363                 return -1;
 364         }
 365
 366         TRACE("Clearing NBD socket");
 367
 368         if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
 369                 int serrno = errno;
 370                 LOG("Failed clearing NBD socket");
 371                 errno = serrno;
 372                 return -1;
 373         }
 374
 375         TRACE("Setting NBD socket");
 376
 377         if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
 378                 int serrno = errno;
 379                 LOG("Failed to set NBD socket");
 380                 errno = serrno;
 381                 return -1;
 382         }
 383
 384         TRACE("Negotiation ended");
 385
 386         return 0;
 387 }
 388
 389 int nbd_disconnect(int fd)
 390 {
 391         ioctl(fd, NBD_CLEAR_QUE);
 392         ioctl(fd, NBD_DISCONNECT);
 393         ioctl(fd, NBD_CLEAR_SOCK);
 394         return 0;
 395 }
 396
 397 int nbd_client(int fd, int csock)
 398 {
 399         int ret;
 400         int serrno;
 401
 402         TRACE("Doing NBD loop");
 403
 404         ret = ioctl(fd, NBD_DO_IT);
 405         serrno = errno;
 406
 407         TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
 408
 409         TRACE("Clearing NBD queue");
 410         ioctl(fd, NBD_CLEAR_QUE);
 411
 412         TRACE("Clearing NBD socket");
 413         ioctl(fd, NBD_CLEAR_SOCK);
 414
 415         errno = serrno;
 416         return ret;
 417 }
 418 #else
 419 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
 420 {
 421     errno = ENOTSUP;
 422     return -1;
 423 }
 424
 425 int nbd_disconnect(int fd)
 426 {
 427     errno = ENOTSUP;
 428     return -1;
 429 }
 430
 431 int nbd_client(int fd, int csock)
 432 {
 433     errno = ENOTSUP;
 434     return -1;
 435 }
 436 #endif
 437
 438 int nbd_send_request(int csock, struct nbd_request *request)
 439 {
 440         uint8_t buf[4 + 4 + 8 + 8 + 4];
 441
 442         cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
 443         cpu_to_be32w((uint32_t*)(buf + 4), request->type);
 444         cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
 445         cpu_to_be64w((uint64_t*)(buf + 16), request->from);
 446         cpu_to_be32w((uint32_t*)(buf + 24), request->len);
 447
 448         TRACE("Sending request to client");
 449
 450         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 451                 LOG("writing to socket failed");
 452                 errno = EINVAL;
 453                 return -1;
 454         }
 455         return 0;
 456 }
 457
 458
 459 static int nbd_receive_request(int csock, struct nbd_request *request)
 460 {
 461         uint8_t buf[4 + 4 + 8 + 8 + 4];
 462         uint32_t magic;
 463
 464         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 465                 LOG("read failed");
 466                 errno = EINVAL;
 467                 return -1;
 468         }
 469
 470         /* Request
 471            [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 472            [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
 473            [ 8 .. 15]   handle
 474            [16 .. 23]   from
 475            [24 .. 27]   len
 476          */
 477
 478         magic = be32_to_cpup((uint32_t*)buf);
 479         request->type  = be32_to_cpup((uint32_t*)(buf + 4));
 480         request->handle = be64_to_cpup((uint64_t*)(buf + 8));
 481         request->from  = be64_to_cpup((uint64_t*)(buf + 16));
 482         request->len   = be32_to_cpup((uint32_t*)(buf + 24));
 483
 484         TRACE("Got request: "
 485               "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
 486               magic, request->type, request->from, request->len);
 487
 488         if (magic != NBD_REQUEST_MAGIC) {
 489                 LOG("invalid magic (got 0x%x)", magic);
 490                 errno = EINVAL;
 491                 return -1;
 492         }
 493         return 0;
 494 }
 495
 496 int nbd_receive_reply(int csock, struct nbd_reply *reply)
 497 {
 498         uint8_t buf[4 + 4 + 8];
 499         uint32_t magic;
 500
 501         memset(buf, 0xAA, sizeof(buf));
 502
 503         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 504                 LOG("read failed");
 505                 errno = EINVAL;
 506                 return -1;
 507         }
 508
 509         /* Reply
 510            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 511            [ 4 ..  7]    error   (0 == no error)
 512            [ 7 .. 15]    handle
 513          */
 514
 515         magic = be32_to_cpup((uint32_t*)buf);
 516         reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
 517         reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
 518
 519         TRACE("Got reply: "
 520               "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
 521               magic, reply->error, reply->handle);
 522
 523         if (magic != NBD_REPLY_MAGIC) {
 524                 LOG("invalid magic (got 0x%x)", magic);
 525                 errno = EINVAL;
 526                 return -1;
 527         }
 528         return 0;
 529 }
 530
 531 static int nbd_send_reply(int csock, struct nbd_reply *reply)
 532 {
 533         uint8_t buf[4 + 4 + 8];
 534
 535         /* Reply
 536            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 537            [ 4 ..  7]    error   (0 == no error)
 538            [ 7 .. 15]    handle
 539          */
 540         cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
 541         cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
 542         cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
 543
 544         TRACE("Sending response to client");
 545
 546         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 547                 LOG("writing to socket failed");
 548                 errno = EINVAL;
 549                 return -1;
 550         }
 551         return 0;
 552 }
 553
 554 int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
 555              off_t *offset, bool readonly, uint8_t *data, int data_size)
 556 {
 557         struct nbd_request request;
 558         struct nbd_reply reply;
 559
 560         TRACE("Reading request.");
 561
 562         if (nbd_receive_request(csock, &request) == -1)
 563                 return -1;
 564
 565         if (request.len > data_size) {
 566                 LOG("len (%u) is larger than max len (%u)",
 567                     request.len, data_size);
 568                 errno = EINVAL;
 569                 return -1;
 570         }
 571
 572         if ((request.from + request.len) < request.from) {
 573                 LOG("integer overflow detected! "
 574                     "you're probably being attacked");
 575                 errno = EINVAL;
 576                 return -1;
 577         }
 578
 579         if ((request.from + request.len) > size) {
 580                 LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
 581                     ", Offset: %" PRIu64 "\n",
 582                     request.from, request.len, (uint64_t)size, dev_offset);
 583                 LOG("requested operation past EOF--bad client?");
 584                 errno = EINVAL;
 585                 return -1;
 586         }
 587
 588         TRACE("Decoding type");
 589
 590         reply.handle = request.handle;
 591         reply.error = 0;
 592
 593         switch (request.type) {
 594         case NBD_CMD_READ:
 595                 TRACE("Request type is READ");
 596
 597                 if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
 598                               request.len / 512) == -1) {
 599                         LOG("reading from file failed");
 600                         errno = EINVAL;
 601                         return -1;
 602                 }
 603                 *offset += request.len;
 604
 605                 TRACE("Read %u byte(s)", request.len);
 606
 607                 if (nbd_send_reply(csock, &reply) == -1)
 608                         return -1;
 609
 610                 TRACE("Sending data to client");
 611
 612                 if (write_sync(csock, data, request.len) != request.len) {
 613                         LOG("writing to socket failed");
 614                         errno = EINVAL;
 615                         return -1;
 616                 }
 617                 break;
 618         case NBD_CMD_WRITE:
 619                 TRACE("Request type is WRITE");
 620
 621                 TRACE("Reading %u byte(s)", request.len);
 622
 623                 if (read_sync(csock, data, request.len) != request.len) {
 624                         LOG("reading from socket failed");
 625                         errno = EINVAL;
 626                         return -1;
 627                 }
 628
 629                 if (readonly) {
 630                         TRACE("Server is read-only, return error");
 631                         reply.error = 1;
 632                 } else {
 633                         TRACE("Writing to device");
 634
 635                         if (bdrv_write(bs, (request.from + dev_offset) / 512,
 636                                        data, request.len / 512) == -1) {
 637                                 LOG("writing to file failed");
 638                                 errno = EINVAL;
 639                                 return -1;
 640                         }
 641
 642                         *offset += request.len;
 643                 }
 644
 645                 if (nbd_send_reply(csock, &reply) == -1)
 646                         return -1;
 647                 break;
 648         case NBD_CMD_DISC:
 649                 TRACE("Request type is DISCONNECT");
 650                 errno = 0;
 651                 return 1;
 652         default:
 653                 LOG("invalid request type (%u) received", request.type);
 654                 errno = EINVAL;
 655                 return -1;
 656         }
 657
 658         TRACE("Request/Reply complete");
 659
 660         return 0;
 661 }