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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
#include <ctype.h>
26
#include <inttypes.h>
27
#include <sys/socket.h>
28
#include <sys/un.h>
29
#include <netinet/in.h>
30
#include <netinet/tcp.h>
31
#include <arpa/inet.h>
32
#include <netdb.h>
33

    
34
#if defined(QEMU_NBD)
35
extern int verbose;
36
#else
37
static int verbose = 0;
38
#endif
39

    
40
#define TRACE(msg, ...) do { \
41
    if (verbose) LOG(msg, ## __VA_ARGS__); \
42
} while(0)
43

    
44
#define LOG(msg, ...) do { \
45
    fprintf(stderr, "%s:%s():L%d: " msg "\n", \
46
            __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
47
} while(0)
48

    
49
/* This is all part of the "official" NBD API */
50

    
51
#define NBD_REQUEST_MAGIC       0x25609513
52
#define NBD_REPLY_MAGIC         0x67446698
53

    
54
#define NBD_SET_SOCK            _IO(0xab, 0)
55
#define NBD_SET_BLKSIZE         _IO(0xab, 1)
56
#define NBD_SET_SIZE            _IO(0xab, 2)
57
#define NBD_DO_IT               _IO(0xab, 3)
58
#define NBD_CLEAR_SOCK          _IO(0xab, 4)
59
#define NBD_CLEAR_QUE           _IO(0xab, 5)
60
#define NBD_PRINT_DEBUG                _IO(0xab, 6)
61
#define NBD_SET_SIZE_BLOCKS        _IO(0xab, 7)
62
#define NBD_DISCONNECT          _IO(0xab, 8)
63

    
64
/* That's all folks */
65

    
66
#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
67
#define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
68

    
69
size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
70
{
71
    size_t offset = 0;
72

    
73
    while (offset < size) {
74
        ssize_t len;
75

    
76
        if (do_read) {
77
            len = read(fd, buffer + offset, size - offset);
78
        } else {
79
            len = write(fd, buffer + offset, size - offset);
80
        }
81

    
82
        /* recoverable error */
83
        if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
84
            continue;
85
        }
86

    
87
        /* eof */
88
        if (len == 0) {
89
            break;
90
        }
91

    
92
        /* unrecoverable error */
93
        if (len == -1) {
94
            return 0;
95
        }
96

    
97
        offset += len;
98
    }
99

    
100
    return offset;
101
}
102

    
103
int tcp_socket_outgoing(const char *address, uint16_t port)
104
{
105
    int s;
106
    struct in_addr in;
107
    struct sockaddr_in addr;
108
    int serrno;
109

    
110
    s = socket(PF_INET, SOCK_STREAM, 0);
111
    if (s == -1) {
112
        return -1;
113
    }
114

    
115
    if (inet_aton(address, &in) == 0) {
116
        struct hostent *ent;
117

    
118
        ent = gethostbyname(address);
119
        if (ent == NULL) {
120
            goto error;
121
        }
122

    
123
        memcpy(&in, ent->h_addr, sizeof(in));
124
    }
125

    
126
    addr.sin_family = AF_INET;
127
    addr.sin_port = htons(port);
128
    memcpy(&addr.sin_addr.s_addr, &in, sizeof(in));
129

    
130
    if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
131
        goto error;
132
    }
133

    
134
    return s;
135
error:
136
    serrno = errno;
137
    close(s);
138
    errno = serrno;
139
    return -1;
140
}
141

    
142
int tcp_socket_incoming(const char *address, uint16_t port)
143
{
144
    int s;
145
    struct in_addr in;
146
    struct sockaddr_in addr;
147
    int serrno;
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, &opt, sizeof(opt)) == -1) {
172
        goto error;
173
    }
174

    
175
    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
176
        goto error;
177
    }
178

    
179
    if (listen(s, 128) == -1) {
180
        goto error;
181
    }
182

    
183
    return s;
184
error:
185
    serrno = errno;
186
    close(s);
187
    errno = serrno;
188
    return -1;
189
}
190

    
191
int unix_socket_incoming(const char *path)
192
{
193
    int s;
194
    struct sockaddr_un addr;
195
    int serrno;
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
    serrno = errno;
217
    close(s);
218
    errno = serrno;
219
    return -1;
220
}
221

    
222
int unix_socket_outgoing(const char *path)
223
{
224
    int s;
225
    struct sockaddr_un addr;
226
    int serrno;
227

    
228
    s = socket(PF_UNIX, SOCK_STREAM, 0);
229
    if (s == -1) {
230
        return -1;
231
    }
232

    
233
    memset(&addr, 0, sizeof(addr));
234
    addr.sun_family = AF_UNIX;
235
    pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
236

    
237
    if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
238
        goto error;
239
    }
240

    
241
    return s;
242
error:
243
    serrno = errno;
244
    close(s);
245
    errno = serrno;
246
    return -1;
247
}
248

    
249

    
250
/* Basic flow
251

252
   Server         Client
253

254
   Negotiate
255
                  Request
256
   Response
257
                  Request
258
   Response
259
                  ...
260
   ...
261
                  Request (type == 2)
262
*/
263

    
264
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size)
265
{
266
        char buf[8 + 8 + 8 + 128];
267

    
268
        /* Negotiate
269
           [ 0 ..   7]   passwd   ("NBDMAGIC")
270
           [ 8 ..  15]   magic    (0x00420281861253)
271
           [16 ..  23]   size
272
           [24 .. 151]   reserved (0)
273
         */
274

    
275
        TRACE("Beginning negotiation.");
276
        memcpy(buf, "NBDMAGIC", 8);
277
        cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
278
        cpu_to_be64w((uint64_t*)(buf + 16), size);
279
        memset(buf + 24, 0, 128);
280

    
281
        if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
282
                LOG("write failed");
283
                errno = EINVAL;
284
                return -1;
285
        }
286

    
287
        TRACE("Negotation succeeded.");
288

    
289
        return 0;
290
}
291

    
292
int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
293
{
294
        char buf[8 + 8 + 8 + 128];
295
        uint64_t magic;
296

    
297
        TRACE("Receiving negotation.");
298

    
299
        if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
300
                LOG("read failed");
301
                errno = EINVAL;
302
                return -1;
303
        }
304

    
305
        magic = be64_to_cpup((uint64_t*)(buf + 8));
306
        *size = be64_to_cpup((uint64_t*)(buf + 16));
307
        *blocksize = 1024;
308

    
309
        TRACE("Magic is %c%c%c%c%c%c%c%c",
310
              isprint(buf[0]) ? buf[0] : '.',
311
              isprint(buf[1]) ? buf[1] : '.',
312
              isprint(buf[2]) ? buf[2] : '.',
313
              isprint(buf[3]) ? buf[3] : '.',
314
              isprint(buf[4]) ? buf[4] : '.',
315
              isprint(buf[5]) ? buf[5] : '.',
316
              isprint(buf[6]) ? buf[6] : '.',
317
              isprint(buf[7]) ? buf[7] : '.');
318
        TRACE("Magic is 0x%" PRIx64, magic);
319
        TRACE("Size is %" PRIu64, *size);
320

    
321
        if (memcmp(buf, "NBDMAGIC", 8) != 0) {
322
                LOG("Invalid magic received");
323
                errno = EINVAL;
324
                return -1;
325
        }
326

    
327
        TRACE("Checking magic");
328

    
329
        if (magic != 0x00420281861253LL) {
330
                LOG("Bad magic received");
331
                errno = EINVAL;
332
                return -1;
333
        }
334
        return 0;
335
}
336

    
337
int nbd_init(int fd, int csock, off_t size, size_t blocksize)
338
{
339
        TRACE("Setting block size to %lu", (unsigned long)blocksize);
340

    
341
        if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
342
                int serrno = errno;
343
                LOG("Failed setting NBD block size");
344
                errno = serrno;
345
                return -1;
346
        }
347

    
348
        TRACE("Setting size to %llu block(s)",
349
              (unsigned long long)(size / blocksize));
350

    
351
        if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) == -1) {
352
                int serrno = errno;
353
                LOG("Failed setting size (in blocks)");
354
                errno = serrno;
355
                return -1;
356
        }
357

    
358
        TRACE("Clearing NBD socket");
359

    
360
        if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
361
                int serrno = errno;
362
                LOG("Failed clearing NBD socket");
363
                errno = serrno;
364
                return -1;
365
        }
366

    
367
        TRACE("Setting NBD socket");
368

    
369
        if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
370
                int serrno = errno;
371
                LOG("Failed to set NBD socket");
372
                errno = serrno;
373
                return -1;
374
        }
375

    
376
        TRACE("Negotiation ended");
377

    
378
        return 0;
379
}
380

    
381
int nbd_disconnect(int fd)
382
{
383
        ioctl(fd, NBD_CLEAR_QUE);
384
        ioctl(fd, NBD_DISCONNECT);
385
        ioctl(fd, NBD_CLEAR_SOCK);
386
        return 0;
387
}
388

    
389
int nbd_client(int fd, int csock)
390
{
391
        int ret;
392
        int serrno;
393

    
394
        TRACE("Doing NBD loop");
395

    
396
        ret = ioctl(fd, NBD_DO_IT);
397
        serrno = errno;
398

    
399
        TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
400

    
401
        TRACE("Clearing NBD queue");
402
        ioctl(fd, NBD_CLEAR_QUE);
403

    
404
        TRACE("Clearing NBD socket");
405
        ioctl(fd, NBD_CLEAR_SOCK);
406

    
407
        errno = serrno;
408
        return ret;
409
}
410

    
411
int nbd_send_request(int csock, struct nbd_request *request)
412
{
413
        uint8_t buf[4 + 4 + 8 + 8 + 4];
414

    
415
        cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
416
        cpu_to_be32w((uint32_t*)(buf + 4), request->type);
417
        cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
418
        cpu_to_be64w((uint64_t*)(buf + 16), request->from);
419
        cpu_to_be32w((uint32_t*)(buf + 24), request->len);
420

    
421
        TRACE("Sending request to client");
422

    
423
        if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
424
                LOG("writing to socket failed");
425
                errno = EINVAL;
426
                return -1;
427
        }
428
        return 0;
429
}
430

    
431

    
432
static int nbd_receive_request(int csock, struct nbd_request *request)
433
{
434
        uint8_t buf[4 + 4 + 8 + 8 + 4];
435
        uint32_t magic;
436

    
437
        if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
438
                LOG("read failed");
439
                errno = EINVAL;
440
                return -1;
441
        }
442

    
443
        /* Request
444
           [ 0 ..  3]   magic   (NBD_REQUEST_MAGIC)
445
           [ 4 ..  7]   type    (0 == READ, 1 == WRITE)
446
           [ 8 .. 15]   handle
447
           [16 .. 23]   from
448
           [24 .. 27]   len
449
         */
450

    
451
        magic = be32_to_cpup((uint32_t*)buf);
452
        request->type  = be32_to_cpup((uint32_t*)(buf + 4));
453
        request->handle = be64_to_cpup((uint64_t*)(buf + 8));
454
        request->from  = be64_to_cpup((uint64_t*)(buf + 16));
455
        request->len   = be32_to_cpup((uint32_t*)(buf + 24));
456

    
457
        TRACE("Got request: "
458
              "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
459
              magic, request->type, request->from, request->len);
460

    
461
        if (magic != NBD_REQUEST_MAGIC) {
462
                LOG("invalid magic (got 0x%x)", magic);
463
                errno = EINVAL;
464
                return -1;
465
        }
466
}
467

    
468
int nbd_receive_reply(int csock, struct nbd_reply *reply)
469
{
470
        uint8_t buf[4 + 4 + 8];
471
        uint32_t magic;
472

    
473
        memset(buf, 0xAA, sizeof(buf));
474

    
475
        if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
476
                LOG("read failed");
477
                errno = EINVAL;
478
                return -1;
479
        }
480

    
481
        /* Reply
482
           [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
483
           [ 4 ..  7]    error   (0 == no error)
484
           [ 7 .. 15]    handle
485
         */
486

    
487
        magic = be32_to_cpup((uint32_t*)buf);
488
        reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
489
        reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
490

    
491
        TRACE("Got reply: "
492
              "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
493
              magic, reply->error, reply->handle);
494

    
495
        if (magic != NBD_REPLY_MAGIC) {
496
                LOG("invalid magic (got 0x%x)", magic);
497
                errno = EINVAL;
498
                return -1;
499
        }
500
        return 0;
501
}
502

    
503
static int nbd_send_reply(int csock, struct nbd_reply *reply)
504
{
505
        uint8_t buf[4 + 4 + 8];
506

    
507
        /* Reply
508
           [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
509
           [ 4 ..  7]    error   (0 == no error)
510
           [ 7 .. 15]    handle
511
         */
512
        cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
513
        cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
514
        cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
515

    
516
        TRACE("Sending response to client");
517

    
518
        if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
519
                LOG("writing to socket failed");
520
                errno = EINVAL;
521
                return -1;
522
        }
523
        return 0;
524
}
525

    
526
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
527
             off_t *offset, bool readonly, uint8_t *data, int data_size)
528
{
529
        struct nbd_request request;
530
        struct nbd_reply reply;
531

    
532
        TRACE("Reading request.");
533

    
534
        if (nbd_receive_request(csock, &request) == -1)
535
                return -1;
536

    
537
        if (request.len > data_size) {
538
                LOG("len (%u) is larger than max len (%u)",
539
                    request.len, data_size);
540
                errno = EINVAL;
541
                return -1;
542
        }
543

    
544
        if ((request.from + request.len) < request.from) {
545
                LOG("integer overflow detected! "
546
                    "you're probably being attacked");
547
                errno = EINVAL;
548
                return -1;
549
        }
550

    
551
        if ((request.from + request.len) > size) {
552
                LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
553
                    ", Offset: %" PRIu64 "\n",
554
                     request.from, request.len, size, dev_offset);
555
                LOG("requested operation past EOF--bad client?");
556
                errno = EINVAL;
557
                return -1;
558
        }
559

    
560
        TRACE("Decoding type");
561

    
562
        reply.handle = request.handle;
563
        reply.error = 0;
564

    
565
        switch (request.type) {
566
        case NBD_CMD_READ:
567
                TRACE("Request type is READ");
568

    
569
                if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
570
                              request.len / 512) == -1) {
571
                        LOG("reading from file failed");
572
                        errno = EINVAL;
573
                        return -1;
574
                }
575
                *offset += request.len;
576

    
577
                TRACE("Read %u byte(s)", request.len);
578

    
579
                if (nbd_send_reply(csock, &reply) == -1)
580
                        return -1;
581

    
582
                TRACE("Sending data to client");
583

    
584
                if (write_sync(csock, data, request.len) != request.len) {
585
                        LOG("writing to socket failed");
586
                        errno = EINVAL;
587
                        return -1;
588
                }
589
                break;
590
        case NBD_CMD_WRITE:
591
                TRACE("Request type is WRITE");
592

    
593
                TRACE("Reading %u byte(s)", request.len);
594

    
595
                if (read_sync(csock, data, request.len) != request.len) {
596
                        LOG("reading from socket failed");
597
                        errno = EINVAL;
598
                        return -1;
599
                }
600

    
601
                if (readonly) {
602
                        TRACE("Server is read-only, return error");
603
                        reply.error = 1;
604
                } else {
605
                        TRACE("Writing to device");
606

    
607
                        if (bdrv_write(bs, (request.from + dev_offset) / 512,
608
                                       data, request.len / 512) == -1) {
609
                                LOG("writing to file failed");
610
                                errno = EINVAL;
611
                                return -1;
612
                        }
613

    
614
                        *offset += request.len;
615
                }
616

    
617
                if (nbd_send_reply(csock, &reply) == -1)
618
                        return -1;
619
                break;
620
        case NBD_CMD_DISC:
621
                TRACE("Request type is DISCONNECT");
622
                errno = 0;
623
                return 1;
624
        default:
625
                LOG("invalid request type (%u) received", request.type);
626
                errno = EINVAL;
627
                return -1;
628
        }
629

    
630
        TRACE("Request/Reply complete");
631

    
632
        return 0;
633
}