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 #define NBD_REQUEST_SIZE        (4 + 2 + 2 + 8 + 8 + 4)
  41 #define NBD_REPLY_SIZE          (4 + 4 + 8)
  42 #define NBD_REQUEST_MAGIC       0x25609513
  43 #define NBD_REPLY_MAGIC         0x67446698
  44 #define NBD_OPTS_MAGIC          0x49484156454F5054LL
  45 #define NBD_CLIENT_MAGIC        0x0000420281861253LL
  46 #define NBD_REP_MAGIC           0x0003e889045565a9LL
  47
  48 #define NBD_SET_SOCK            _IO(0xab, 0)
  49 #define NBD_SET_BLKSIZE         _IO(0xab, 1)
  50 #define NBD_SET_SIZE            _IO(0xab, 2)
  51 #define NBD_DO_IT               _IO(0xab, 3)
  52 #define NBD_CLEAR_SOCK          _IO(0xab, 4)
  53 #define NBD_CLEAR_QUE           _IO(0xab, 5)
  54 #define NBD_PRINT_DEBUG         _IO(0xab, 6)
  55 #define NBD_SET_SIZE_BLOCKS     _IO(0xab, 7)
  56 #define NBD_DISCONNECT          _IO(0xab, 8)
  57 #define NBD_SET_TIMEOUT         _IO(0xab, 9)
  58 #define NBD_SET_FLAGS           _IO(0xab, 10)
  59
  60 #define NBD_OPT_EXPORT_NAME     (1)
  61 #define NBD_OPT_ABORT           (2)
  62 #define NBD_OPT_LIST            (3)
  63 #define NBD_OPT_PEEK_EXPORT     (4)
  64 #define NBD_OPT_STARTTLS        (5)
  65
  66 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
  67  * but only a limited set of errno values is specified in the protocol.
  68  * Everything else is squashed to EINVAL.
  69  */
  70 #define NBD_SUCCESS    0
  71 #define NBD_EPERM      1
  72 #define NBD_EIO        5
  73 #define NBD_ENOMEM     12
  74 #define NBD_EINVAL     22
  75 #define NBD_ENOSPC     28
  76 #define NBD_ESHUTDOWN  108
  77
  78 /* nbd_read_eof
  79  * Tries to read @size bytes from @ioc. Returns number of bytes actually read.
  80  * May return a value >= 0 and < size only on EOF, i.e. when iteratively called
  81  * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
  82  * iteratively.
  83  */
  84 static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
  85                                    Error **errp)
  86 {
  87     struct iovec iov = { .iov_base = buffer, .iov_len = size };
  88     /* Sockets are kept in blocking mode in the negotiation phase.  After
  89      * that, a non-readable socket simply means that another thread stole
  90      * our request/reply.  Synchronization is done with recv_coroutine, so
  91      * that this is coroutine-safe.
  92      */
  93     return nbd_rwv(ioc, &iov, 1, size, true, errp);
  94 }
  95
  96 /* nbd_read
  97  * Reads @size bytes from @ioc. Returns 0 on success.
  98  */
  99 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
 100                            Error **errp)
 101 {
 102     ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
 103
 104     if (ret >= 0 && ret != size) {
 105         ret = -EINVAL;
 106         error_setg(errp, "End of file");
 107     }
 108
 109     return ret < 0 ? ret : 0;
 110 }
 111
 112 /* nbd_write
 113  * Writes @size bytes to @ioc. Returns 0 on success.
 114  */
 115 static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,
 116                             Error **errp)
 117 {
 118     struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
 119
 120     ssize_t ret = nbd_rwv(ioc, &iov, 1, size, false, errp);
 121
 122     assert(ret < 0 || ret == size);
 123
 124     return ret < 0 ? ret : 0;
 125 }
 126
 127 struct NBDTLSHandshakeData {
 128     GMainLoop *loop;
 129     bool complete;
 130     Error *error;
 131 };
 132
 133
 134 void nbd_tls_handshake(QIOTask *task,
 135                        void *opaque);
 136
 137 int nbd_drop(QIOChannel *ioc, size_t size, Error **errp);
 138
 139 #endif