xemu/qapi/sockets.json
Daniel P. Berrange 1723d6b1cf sockets: allow SocketAddress 'fd' to reference numeric file descriptors
The SocketAddress 'fd' kind accepts the name of a file descriptor passed
to the monitor with the 'getfd' command. This makes it impossible to use
the 'fd' kind in cases where a monitor is not available. This can apply in
handling command line argv at startup, or simply if internal code wants to
use SocketAddress and pass a numeric FD it has acquired from elsewhere.

Fortunately the 'getfd' command mandated that the FD names must not start
with a leading digit. We can thus safely extend semantics of the
SocketAddress 'fd' kind, to allow a purely numeric name to reference an
file descriptor that QEMU already has open. There will be restrictions on
when each kind can be used.

In codepaths where we are handling a monitor command (ie cur_mon != NULL),
we will only support use of named file descriptors as before. Use of FD
numbers is still not permitted for monitor commands.

In codepaths where we are not handling a monitor command (ie cur_mon ==
NULL), we will not support named file descriptors. Instead we can reference
FD numers explicitly. This allows the app spawning QEMU to intentionally
"leak" a pre-opened socket to QEMU and reference that in a SocketAddress
definition, or for code inside QEMU to pass pre-opened FDs around.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2018-03-13 18:06:06 +00:00

155 lines
3.3 KiB
Python

# -*- Mode: Python -*-
##
# = Socket data types
##
{ 'include': 'common.json' }
##
# @NetworkAddressFamily:
#
# The network address family
#
# @ipv4: IPV4 family
#
# @ipv6: IPV6 family
#
# @unix: unix socket
#
# @vsock: vsock family (since 2.8)
#
# @unknown: otherwise
#
# Since: 2.1
##
{ 'enum': 'NetworkAddressFamily',
'data': [ 'ipv4', 'ipv6', 'unix', 'vsock', 'unknown' ] }
##
# @InetSocketAddressBase:
#
# @host: host part of the address
# @port: port part of the address
##
{ 'struct': 'InetSocketAddressBase',
'data': {
'host': 'str',
'port': 'str' } }
##
# @InetSocketAddress:
#
# Captures a socket address or address range in the Internet namespace.
#
# @numeric: true if the host/port are guaranteed to be numeric,
# false if name resolution should be attempted. Defaults to false.
# (Since 2.9)
#
# @to: If present, this is range of possible addresses, with port
# between @port and @to.
#
# @ipv4: whether to accept IPv4 addresses, default try both IPv4 and IPv6
#
# @ipv6: whether to accept IPv6 addresses, default try both IPv4 and IPv6
#
# Since: 1.3
##
{ 'struct': 'InetSocketAddress',
'base': 'InetSocketAddressBase',
'data': {
'*numeric': 'bool',
'*to': 'uint16',
'*ipv4': 'bool',
'*ipv6': 'bool' } }
##
# @UnixSocketAddress:
#
# Captures a socket address in the local ("Unix socket") namespace.
#
# @path: filesystem path to use
#
# Since: 1.3
##
{ 'struct': 'UnixSocketAddress',
'data': {
'path': 'str' } }
##
# @VsockSocketAddress:
#
# Captures a socket address in the vsock namespace.
#
# @cid: unique host identifier
# @port: port
#
# Note: string types are used to allow for possible future hostname or
# service resolution support.
#
# Since: 2.8
##
{ 'struct': 'VsockSocketAddress',
'data': {
'cid': 'str',
'port': 'str' } }
##
# @SocketAddressLegacy:
#
# Captures the address of a socket, which could also be a named file descriptor
#
# Note: This type is deprecated in favor of SocketAddress. The
# difference between SocketAddressLegacy and SocketAddress is that the
# latter is a flat union rather than a simple union. Flat is nicer
# because it avoids nesting on the wire, i.e. that form has fewer {}.
#
# Since: 1.3
##
{ 'union': 'SocketAddressLegacy',
'data': {
'inet': 'InetSocketAddress',
'unix': 'UnixSocketAddress',
'vsock': 'VsockSocketAddress',
'fd': 'String' } }
##
# @SocketAddressType:
#
# Available SocketAddress types
#
# @inet: Internet address
#
# @unix: Unix domain socket
#
# @vsock: VMCI address
#
# @fd: decimal is for file descriptor number, otherwise a file descriptor name.
# Named file descriptors are permitted in monitor commands, in combination
# with the 'getfd' command. Decimal file descriptors are permitted at
# startup or other contexts where no monitor context is active.
#
# Since: 2.9
##
{ 'enum': 'SocketAddressType',
'data': [ 'inet', 'unix', 'vsock', 'fd' ] }
##
# @SocketAddress:
#
# Captures the address of a socket, which could also be a named file
# descriptor
#
# @type: Transport type
#
# Since: 2.9
##
{ 'union': 'SocketAddress',
'base': { 'type': 'SocketAddressType' },
'discriminator': 'type',
'data': { 'inet': 'InetSocketAddress',
'unix': 'UnixSocketAddress',
'vsock': 'VsockSocketAddress',
'fd': 'String' } }