nbd/nbd-internal.h

   1 /*
   2  * NBD Internal Declarations
   3  *
   4  * Copyright (C) 2016 Red Hat, Inc.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #ifndef NBD_INTERNAL_H
  11 #define NBD_INTERNAL_H
  12 #include "block/nbd.h"
  13 #include "sysemu/block-backend.h"
  14 #include "io/channel-tls.h"
  15
  16 #include "qemu/coroutine.h"
  17 #include "qemu/iov.h"
  18
  19 #ifndef _WIN32
  20 #include <sys/ioctl.h>
  21 #endif
  22 #if defined(__sun__) || defined(__HAIKU__)
  23 #include <sys/ioccom.h>
  24 #endif
  25
  26 #ifdef __linux__
  27 #include <linux/fs.h>
  28 #endif
  29
  30 #include "qemu/bswap.h"
  31 #include "qemu/queue.h"
  32 #include "qemu/main-loop.h"
  33
  34 /* This is all part of the "official" NBD API.
  35  *
  36  * The most up-to-date documentation is available at:
  37  * https://github.com/yoe/nbd/blob/master/doc/proto.md
  38  */
  39
  40 /* Size of all NBD_OPT_*, without payload */
  41 #define NBD_REQUEST_SIZE        (4 + 2 + 2 + 8 + 8 + 4)
  42 /* Size of all NBD_REP_* sent in answer to most NBD_OPT_*, without payload */
  43 #define NBD_REPLY_SIZE          (4 + 4 + 8)
  44
  45 #define NBD_REQUEST_MAGIC       0x25609513
  46 #define NBD_REPLY_MAGIC         0x67446698
  47 #define NBD_OPTS_MAGIC          0x49484156454F5054LL
  48 #define NBD_CLIENT_MAGIC        0x0000420281861253LL
  49 #define NBD_REP_MAGIC           0x0003e889045565a9LL
  50
  51 #define NBD_SET_SOCK            _IO(0xab, 0)
  52 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  53 #define NBD_SET_SIZE            _IO(0xab, 2)
  54 #define NBD_DO_IT               _IO(0xab, 3)
  55 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  56 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  57 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  58 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  59 #define NBD_DISCONNECT          _IO(0xab, 8)
  60 #define NBD_SET_TIMEOUT         _IO(0xab, 9)
  61 #define NBD_SET_FLAGS           _IO(0xab, 10)
  62
  63 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
  64  * but only a limited set of errno values is specified in the protocol.
  65  * Everything else is squashed to EINVAL.
  66  */
  67 #define NBD_SUCCESS    0
  68 #define NBD_EPERM      1
  69 #define NBD_EIO        5
  70 #define NBD_ENOMEM     12
  71 #define NBD_EINVAL     22
  72 #define NBD_ENOSPC     28
  73 #define NBD_ESHUTDOWN  108
  74
  75 /* nbd_read_eof
  76  * Tries to read @size bytes from @ioc. Returns number of bytes actually read.
  77  * May return a value >= 0 and < size only on EOF, i.e. when iteratively called
  78  * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
  79  * iteratively.
  80  */
  81 static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
  82                                    Error **errp)
  83 {
  84     struct iovec iov = { .iov_base = buffer, .iov_len = size };
  85     /* Sockets are kept in blocking mode in the negotiation phase.  After
  86      * that, a non-readable socket simply means that another thread stole
  87      * our request/reply.  Synchronization is done with recv_coroutine, so
  88      * that this is coroutine-safe.
  89      */
  90     return nbd_rwv(ioc, &iov, 1, size, true, errp);
  91 }
  92
  93 /* nbd_read
  94  * Reads @size bytes from @ioc. Returns 0 on success.
  95  */
  96 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
  97                            Error **errp)
  98 {
  99     ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
 100
 101     if (ret >= 0 && ret != size) {
 102         ret = -EINVAL;
 103         error_setg(errp, "End of file");
 104     }
 105
 106     return ret < 0 ? ret : 0;
 107 }
 108
 109 /* nbd_write
 110  * Writes @size bytes to @ioc. Returns 0 on success.
 111  */
 112 static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,
 113                             Error **errp)
 114 {
 115     struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
 116
 117     ssize_t ret = nbd_rwv(ioc, &iov, 1, size, false, errp);
 118
 119     assert(ret < 0 || ret == size);
 120
 121     return ret < 0 ? ret : 0;
 122 }
 123
 124 struct NBDTLSHandshakeData {
 125     GMainLoop *loop;
 126     bool complete;
 127     Error *error;
 128 };
 129
 130
 131 void nbd_tls_handshake(QIOTask *task,
 132                        void *opaque);
 133 const char *nbd_opt_lookup(uint32_t opt);
 134 const char *nbd_rep_lookup(uint32_t rep);
 135 const char *nbd_info_lookup(uint16_t info);
 136 const char *nbd_cmd_lookup(uint16_t info);
 137
 138 int nbd_drop(QIOChannel *ioc, size_t size, Error **errp);
 139
 140 #endif