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 /* Size of reply to NBD_OPT_EXPORT_NAME */
  45 #define NBD_REPLY_EXPORT_NAME_SIZE  (8 + 2 + 124)
  46 /* Size of oldstyle negotiation */
  47 #define NBD_OLDSTYLE_NEGOTIATE_SIZE (8 + 8 + 8 + 4 + 124)
  48
  49 #define NBD_REQUEST_MAGIC       0x25609513
  50 #define NBD_REPLY_MAGIC         0x67446698
  51 #define NBD_OPTS_MAGIC          0x49484156454F5054LL
  52 #define NBD_CLIENT_MAGIC        0x0000420281861253LL
  53 #define NBD_REP_MAGIC           0x0003e889045565a9LL
  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 #define NBD_SET_TIMEOUT         _IO(0xab, 9)
  65 #define NBD_SET_FLAGS           _IO(0xab, 10)
  66
  67 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
  68  * but only a limited set of errno values is specified in the protocol.
  69  * Everything else is squashed to EINVAL.
  70  */
  71 #define NBD_SUCCESS    0
  72 #define NBD_EPERM      1
  73 #define NBD_EIO        5
  74 #define NBD_ENOMEM     12
  75 #define NBD_EINVAL     22
  76 #define NBD_ENOSPC     28
  77 #define NBD_ESHUTDOWN  108
  78
  79 /* nbd_read_eof
  80  * Tries to read @size bytes from @ioc. Returns number of bytes actually read.
  81  * May return a value >= 0 and < size only on EOF, i.e. when iteratively called
  82  * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
  83  * iteratively.
  84  */
  85 static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
  86                                    Error **errp)
  87 {
  88     struct iovec iov = { .iov_base = buffer, .iov_len = size };
  89     /* Sockets are kept in blocking mode in the negotiation phase.  After
  90      * that, a non-readable socket simply means that another thread stole
  91      * our request/reply.  Synchronization is done with recv_coroutine, so
  92      * that this is coroutine-safe.
  93      */
  94     return nbd_rwv(ioc, &iov, 1, size, true, errp);
  95 }
  96
  97 /* nbd_read
  98  * Reads @size bytes from @ioc. Returns 0 on success.
  99  */
 100 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
 101                            Error **errp)
 102 {
 103     ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
 104
 105     if (ret >= 0 && ret != size) {
 106         ret = -EINVAL;
 107         error_setg(errp, "End of file");
 108     }
 109
 110     return ret < 0 ? ret : 0;
 111 }
 112
 113 /* nbd_write
 114  * Writes @size bytes to @ioc. Returns 0 on success.
 115  */
 116 static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,
 117                             Error **errp)
 118 {
 119     struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
 120
 121     ssize_t ret = nbd_rwv(ioc, &iov, 1, size, false, errp);
 122
 123     assert(ret < 0 || ret == size);
 124
 125     return ret < 0 ? ret : 0;
 126 }
 127
 128 struct NBDTLSHandshakeData {
 129     GMainLoop *loop;
 130     bool complete;
 131     Error *error;
 132 };
 133
 134
 135 void nbd_tls_handshake(QIOTask *task,
 136                        void *opaque);
 137 const char *nbd_opt_lookup(uint32_t opt);
 138 const char *nbd_rep_lookup(uint32_t rep);
 139 const char *nbd_info_lookup(uint16_t info);
 140 const char *nbd_cmd_lookup(uint16_t info);
 141
 142 int nbd_drop(QIOChannel *ioc, size_t size, Error **errp);
 143
 144 #endif