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., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA
  18  */
  19
  20 #include "nbd.h"
  21
  22 #include <errno.h>
  23 #include <string.h>
  24 #ifndef _WIN32
  25 #include <sys/ioctl.h>
  26 #endif
  27 #ifdef __sun__
  28 #include <sys/ioccom.h>
  29 #endif
  30 #include <ctype.h>
  31 #include <inttypes.h>
  32
  33 #include "qemu_socket.h"
  34
  35 //#define DEBUG_NBD
  36
  37 #ifdef DEBUG_NBD
  38 #define TRACE(msg, ...) do { \
  39     LOG(msg, ## __VA_ARGS__); \
  40 } while(0)
  41 #else
  42 #define TRACE(msg, ...) \
  43     do { } while (0)
  44 #endif
  45
  46 #define LOG(msg, ...) do { \
  47     fprintf(stderr, "%s:%s():L%d: " msg "\n", \
  48             __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
  49 } while(0)
  50
  51 /* This is all part of the "official" NBD API */
  52
  53 #define NBD_REQUEST_MAGIC       0x25609513
  54 #define NBD_REPLY_MAGIC         0x67446698
  55
  56 #define NBD_SET_SOCK            _IO(0xab, 0)
  57 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  58 #define NBD_SET_SIZE            _IO(0xab, 2)
  59 #define NBD_DO_IT               _IO(0xab, 3)
  60 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  61 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  62 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  63 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  64 #define NBD_DISCONNECT          _IO(0xab, 8)
  65
  66 /* That's all folks */
  67
  68 #define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
  69 #define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
  70
  71 size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
  72 {
  73     size_t offset = 0;
  74
  75     while (offset < size) {
  76         ssize_t len;
  77
  78         if (do_read) {
  79             len = recv(fd, buffer + offset, size - offset, 0);
  80         } else {
  81             len = send(fd, buffer + offset, size - offset, 0);
  82         }
  83
  84         if (len == -1)
  85             errno = socket_error();
  86
  87         /* recoverable error */
  88         if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
  89             continue;
  90         }
  91
  92         /* eof */
  93         if (len == 0) {
  94             break;
  95         }
  96
  97         /* unrecoverable error */
  98         if (len == -1) {
  99             return 0;
 100         }
 101
 102         offset += len;
 103     }
 104
 105     return offset;
 106 }
 107
 108 int tcp_socket_outgoing(const char *address, uint16_t port)
 109 {
 110     int s;
 111     struct in_addr in;
 112     struct sockaddr_in addr;
 113
 114     s = socket(PF_INET, SOCK_STREAM, 0);
 115     if (s == -1) {
 116         return -1;
 117     }
 118
 119     if (inet_aton(address, &in) == 0) {
 120         struct hostent *ent;
 121
 122         ent = gethostbyname(address);
 123         if (ent == NULL) {
 124             goto error;
 125         }
 126
 127         memcpy(&in, ent->h_addr, sizeof(in));
 128     }
 129
 130     addr.sin_family = AF_INET;
 131     addr.sin_port = htons(port);
 132     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
 133
 134     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 135         goto error;
 136     }
 137
 138     return s;
 139 error:
 140     closesocket(s);
 141     return -1;
 142 }
 143
 144 int tcp_socket_incoming(const char *address, uint16_t port)
 145 {
 146     int s;
 147     struct in_addr in;
 148     struct sockaddr_in addr;
 149     int opt;
 150
 151     s = socket(PF_INET, SOCK_STREAM, 0);
 152     if (s == -1) {
 153         return -1;
 154     }
 155
 156     if (inet_aton(address, &in) == 0) {
 157         struct hostent *ent;
 158
 159         ent = gethostbyname(address);
 160         if (ent == NULL) {
 161             goto error;
 162         }
 163
 164         memcpy(&in, ent->h_addr, sizeof(in));
 165     }
 166
 167     addr.sin_family = AF_INET;
 168     addr.sin_port = htons(port);
 169     memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
 170
 171     opt = 1;
 172     if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
 173                    (const void *) &opt, sizeof(opt)) == -1) {
 174         goto error;
 175     }
 176
 177     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 178         goto error;
 179     }
 180
 181     if (listen(s, 128) == -1) {
 182         goto error;
 183     }
 184
 185     return s;
 186 error:
 187     closesocket(s);
 188     return -1;
 189 }
 190
 191 #ifndef _WIN32
 192 int unix_socket_incoming(const char *path)
 193 {
 194     int s;
 195     struct sockaddr_un addr;
 196
 197     s = socket(PF_UNIX, SOCK_STREAM, 0);
 198     if (s == -1) {
 199         return -1;
 200     }
 201
 202     memset(&addr, 0, sizeof(addr));
 203     addr.sun_family = AF_UNIX;
 204     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 205
 206     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 207         goto error;
 208     }
 209
 210     if (listen(s, 128) == -1) {
 211         goto error;
 212     }
 213
 214     return s;
 215 error:
 216     closesocket(s);
 217     return -1;
 218 }
 219
 220 int unix_socket_outgoing(const char *path)
 221 {
 222     int s;
 223     struct sockaddr_un addr;
 224
 225     s = socket(PF_UNIX, SOCK_STREAM, 0);
 226     if (s == -1) {
 227         return -1;
 228     }
 229
 230     memset(&addr, 0, sizeof(addr));
 231     addr.sun_family = AF_UNIX;
 232     pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
 233
 234     if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
 235         goto error;
 236     }
 237
 238     return s;
 239 error:
 240     closesocket(s);
 241     return -1;
 242 }
 243 #else
 244 int unix_socket_incoming(const char *path)
 245 {
 246     errno = ENOTSUP;
 247     return -1;
 248 }
 249
 250 int unix_socket_outgoing(const char *path)
 251 {
 252     errno = ENOTSUP;
 253     return -1;
 254 }
 255 #endif
 256
 257
 258 /* Basic flow
 259
 260    Server         Client
 261
 262    Negotiate
 263                   Request
 264    Response
 265                   Request
 266    Response
 267                   ...
 268    ...
 269                   Request (type == 2)
 270 */
 271
 272 int nbd_negotiate(int csock, off_t size)
 273 {
 274         char buf[8 + 8 + 8 + 128];
 275
 276         /* Negotiate
 277            [ 0 ..   7]   passwd   ("NBDMAGIC")
 278            [ 8 ..  15]   magic    (0x00420281861253)
 279            [16 ..  23]   size
 280            [24 .. 151]   reserved (0)
 281          */
 282
 283         TRACE("Beginning negotiation.");
 284         memcpy(buf, "NBDMAGIC", 8);
 285         cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
 286         cpu_to_be64w((uint64_t*)(buf + 16), size);
 287         memset(buf + 24, 0, 128);
 288
 289         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 290                 LOG("write failed");
 291                 errno = EINVAL;
 292                 return -1;
 293         }
 294
 295         TRACE("Negotation succeeded.");
 296
 297         return 0;
 298 }
 299
 300 int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
 301 {
 302         char buf[8 + 8 + 8 + 128];
 303         uint64_t magic;
 304
 305         TRACE("Receiving negotation.");
 306
 307         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 308                 LOG("read failed");
 309                 errno = EINVAL;
 310                 return -1;
 311         }
 312
 313         magic = be64_to_cpup((uint64_t*)(buf + 8));
 314         *size = be64_to_cpup((uint64_t*)(buf + 16));
 315         *blocksize = 1024;
 316
 317         TRACE("Magic is %c%c%c%c%c%c%c%c",
 318               qemu_isprint(buf[0]) ? buf[0] : '.',
 319               qemu_isprint(buf[1]) ? buf[1] : '.',
 320               qemu_isprint(buf[2]) ? buf[2] : '.',
 321               qemu_isprint(buf[3]) ? buf[3] : '.',
 322               qemu_isprint(buf[4]) ? buf[4] : '.',
 323               qemu_isprint(buf[5]) ? buf[5] : '.',
 324               qemu_isprint(buf[6]) ? buf[6] : '.',
 325               qemu_isprint(buf[7]) ? buf[7] : '.');
 326         TRACE("Magic is 0x%" PRIx64, magic);
 327         TRACE("Size is %" PRIu64, *size);
 328
 329         if (memcmp(buf, "NBDMAGIC", 8) != 0) {
 330                 LOG("Invalid magic received");
 331                 errno = EINVAL;
 332                 return -1;
 333         }
 334
 335         TRACE("Checking magic");
 336
 337         if (magic != 0x00420281861253LL) {
 338                 LOG("Bad magic received");
 339                 errno = EINVAL;
 340                 return -1;
 341         }
 342         return 0;
 343 }
 344
 345 #ifndef _WIN32
 346 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
 347 {
 348         TRACE("Setting block size to %lu", (unsigned long)blocksize);
 349
 350         if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
 351                 int serrno = errno;
 352                 LOG("Failed setting NBD block size");
 353                 errno = serrno;
 354                 return -1;
 355         }
 356
 357         TRACE("Setting size to %llu block(s)",
 358               (unsigned long long)(size / blocksize));
 359
 360         if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
 361                 int serrno = errno;
 362                 LOG("Failed setting size (in blocks)");
 363                 errno = serrno;
 364                 return -1;
 365         }
 366
 367         TRACE("Clearing NBD socket");
 368
 369         if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
 370                 int serrno = errno;
 371                 LOG("Failed clearing NBD socket");
 372                 errno = serrno;
 373                 return -1;
 374         }
 375
 376         TRACE("Setting NBD socket");
 377
 378         if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
 379                 int serrno = errno;
 380                 LOG("Failed to set NBD socket");
 381                 errno = serrno;
 382                 return -1;
 383         }
 384
 385         TRACE("Negotiation ended");
 386
 387         return 0;
 388 }
 389
 390 int nbd_disconnect(int fd)
 391 {
 392         ioctl(fd, NBD_CLEAR_QUE);
 393         ioctl(fd, NBD_DISCONNECT);
 394         ioctl(fd, NBD_CLEAR_SOCK);
 395         return 0;
 396 }
 397
 398 int nbd_client(int fd, int csock)
 399 {
 400         int ret;
 401         int serrno;
 402
 403         TRACE("Doing NBD loop");
 404
 405         ret = ioctl(fd, NBD_DO_IT);
 406         serrno = errno;
 407
 408         TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
 409
 410         TRACE("Clearing NBD queue");
 411         ioctl(fd, NBD_CLEAR_QUE);
 412
 413         TRACE("Clearing NBD socket");
 414         ioctl(fd, NBD_CLEAR_SOCK);
 415
 416         errno = serrno;
 417         return ret;
 418 }
 419 #else
 420 int nbd_init(int fd, int csock, off_t size, size_t blocksize)
 421 {
 422     errno = ENOTSUP;
 423     return -1;
 424 }
 425
 426 int nbd_disconnect(int fd)
 427 {
 428     errno = ENOTSUP;
 429     return -1;
 430 }
 431
 432 int nbd_client(int fd, int csock)
 433 {
 434     errno = ENOTSUP;
 435     return -1;
 436 }
 437 #endif
 438
 439 int nbd_send_request(int csock, struct nbd_request *request)
 440 {
 441         uint8_t buf[4 + 4 + 8 + 8 + 4];
 442
 443         cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
 444         cpu_to_be32w((uint32_t*)(buf + 4), request->type);
 445         cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
 446         cpu_to_be64w((uint64_t*)(buf + 16), request->from);
 447         cpu_to_be32w((uint32_t*)(buf + 24), request->len);
 448
 449         TRACE("Sending request to client");
 450
 451         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 452                 LOG("writing to socket failed");
 453                 errno = EINVAL;
 454                 return -1;
 455         }
 456         return 0;
 457 }
 458
 459
 460 static int nbd_receive_request(int csock, struct nbd_request *request)
 461 {
 462         uint8_t buf[4 + 4 + 8 + 8 + 4];
 463         uint32_t magic;
 464
 465         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 466                 LOG("read failed");
 467                 errno = EINVAL;
 468                 return -1;
 469         }
 470
 471         /* Request
 472            [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
 473            [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
 474            [ 8 .. 15]   handle
 475            [16 .. 23]   from
 476            [24 .. 27]   len
 477          */
 478
 479         magic = be32_to_cpup((uint32_t*)buf);
 480         request->type  = be32_to_cpup((uint32_t*)(buf + 4));
 481         request->handle = be64_to_cpup((uint64_t*)(buf + 8));
 482         request->from  = be64_to_cpup((uint64_t*)(buf + 16));
 483         request->len   = be32_to_cpup((uint32_t*)(buf + 24));
 484
 485         TRACE("Got request: "
 486               "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
 487               magic, request->type, request->from, request->len);
 488
 489         if (magic != NBD_REQUEST_MAGIC) {
 490                 LOG("invalid magic (got 0x%x)", magic);
 491                 errno = EINVAL;
 492                 return -1;
 493         }
 494         return 0;
 495 }
 496
 497 int nbd_receive_reply(int csock, struct nbd_reply *reply)
 498 {
 499         uint8_t buf[4 + 4 + 8];
 500         uint32_t magic;
 501
 502         memset(buf, 0xAA, sizeof(buf));
 503
 504         if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 505                 LOG("read failed");
 506                 errno = EINVAL;
 507                 return -1;
 508         }
 509
 510         /* Reply
 511            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 512            [ 4 ..  7]    error   (0 == no error)
 513            [ 7 .. 15]    handle
 514          */
 515
 516         magic = be32_to_cpup((uint32_t*)buf);
 517         reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
 518         reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
 519
 520         TRACE("Got reply: "
 521               "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
 522               magic, reply->error, reply->handle);
 523
 524         if (magic != NBD_REPLY_MAGIC) {
 525                 LOG("invalid magic (got 0x%x)", magic);
 526                 errno = EINVAL;
 527                 return -1;
 528         }
 529         return 0;
 530 }
 531
 532 static int nbd_send_reply(int csock, struct nbd_reply *reply)
 533 {
 534         uint8_t buf[4 + 4 + 8];
 535
 536         /* Reply
 537            [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
 538            [ 4 ..  7]    error   (0 == no error)
 539            [ 7 .. 15]    handle
 540          */
 541         cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
 542         cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
 543         cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
 544
 545         TRACE("Sending response to client");
 546
 547         if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
 548                 LOG("writing to socket failed");
 549                 errno = EINVAL;
 550                 return -1;
 551         }
 552         return 0;
 553 }
 554
 555 int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
 556              off_t *offset, bool readonly, uint8_t *data, int data_size)
 557 {
 558         struct nbd_request request;
 559         struct nbd_reply reply;
 560
 561         TRACE("Reading request.");
 562
 563         if (nbd_receive_request(csock, &request) == -1)
 564                 return -1;
 565
 566         if (request.len > data_size) {
 567                 LOG("len (%u) is larger than max len (%u)",
 568                     request.len, data_size);
 569                 errno = EINVAL;
 570                 return -1;
 571         }
 572
 573         if ((request.from + request.len) < request.from) {
 574                 LOG("integer overflow detected! "
 575                     "you're probably being attacked");
 576                 errno = EINVAL;
 577                 return -1;
 578         }
 579
 580         if ((request.from + request.len) > size) {
 581                 LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
 582                     ", Offset: %" PRIu64 "\n",
 583                     request.from, request.len, (uint64_t)size, dev_offset);
 584                 LOG("requested operation past EOF--bad client?");
 585                 errno = EINVAL;
 586                 return -1;
 587         }
 588
 589         TRACE("Decoding type");
 590
 591         reply.handle = request.handle;
 592         reply.error = 0;
 593
 594         switch (request.type) {
 595         case NBD_CMD_READ:
 596                 TRACE("Request type is READ");
 597
 598                 if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
 599                               request.len / 512) == -1) {
 600                         LOG("reading from file failed");
 601                         errno = EINVAL;
 602                         return -1;
 603                 }
 604                 *offset += request.len;
 605
 606                 TRACE("Read %u byte(s)", request.len);
 607
 608                 if (nbd_send_reply(csock, &reply) == -1)
 609                         return -1;
 610
 611                 TRACE("Sending data to client");
 612
 613                 if (write_sync(csock, data, request.len) != request.len) {
 614                         LOG("writing to socket failed");
 615                         errno = EINVAL;
 616                         return -1;
 617                 }
 618                 break;
 619         case NBD_CMD_WRITE:
 620                 TRACE("Request type is WRITE");
 621
 622                 TRACE("Reading %u byte(s)", request.len);
 623
 624                 if (read_sync(csock, data, request.len) != request.len) {
 625                         LOG("reading from socket failed");
 626                         errno = EINVAL;
 627                         return -1;
 628                 }
 629
 630                 if (readonly) {
 631                         TRACE("Server is read-only, return error");
 632                         reply.error = 1;
 633                 } else {
 634                         TRACE("Writing to device");
 635
 636                         if (bdrv_write(bs, (request.from + dev_offset) / 512,
 637                                        data, request.len / 512) == -1) {
 638                                 LOG("writing to file failed");
 639                                 errno = EINVAL;
 640                                 return -1;
 641                         }
 642
 643                         *offset += request.len;
 644                 }
 645
 646                 if (nbd_send_reply(csock, &reply) == -1)
 647                         return -1;
 648                 break;
 649         case NBD_CMD_DISC:
 650                 TRACE("Request type is DISCONNECT");
 651                 errno = 0;
 652                 return 1;
 653         default:
 654                 LOG("invalid request type (%u) received", request.type);
 655                 errno = EINVAL;
 656                 return -1;
 657         }
 658
 659         TRACE("Request/Reply complete");
 660
 661         return 0;
 662 }