# ----------------------------------------------------------------------------
# Description : Name/address resolution logic
# Git repository : https://gitlab.com/qblox/packages/software/qblox_instruments.git
# Copyright (C) Qblox BV (2021)
# ----------------------------------------------------------------------------
# -- include -----------------------------------------------------------------
import re
import socket
import logging
import ipaddress
from collections import namedtuple
from typing import Optional, Union
from qblox_instruments.pnp import PlugAndPlay
# -- definitions -------------------------------------------------------------
# Port definitions for direct connections to an instrument.
MAIN_SCPI_PORT = 5025
MAIN_CFG_PORT = 5026
MAIN_ZMQ_RR_PORT = 20802
MAIN_ZMQ_PS_PORT = 20803
# Port definitions forwarded by the CMM to modules in the cluster, for direct
# module connections if needed.
MODULE_SCPI_PORT_OFFSET = 25000
MODULE_CFG_PORT_OFFSET = 26000
MODULE_ZMQ_RR_PORT_OFFSET = 23000
MODULE_ZMQ_PS_PORT_OFFSET = 24000
# Slot index of the CMM.
CMM_SLOT_INDEX = 0
# Structure returned by resolve(). See resolve() for more information.
AddressInfo = namedtuple(
"AddressInfo",
[
"protocol",
"address",
"slot_index",
"scpi_port",
"cfg_port",
"zmq_rr_port",
"zmq_ps_port",
],
)
AddressInfo.__doc__ = """
Connection information structure. Can be constructed from an instrument
identifier via resolve().
"""
AddressInfo.protocol.__doc__ = """
:str: The protocol that must be used to connect. Can be:
- ``"ip"`` for a normal IP-based connection; or
- ``"pnp"`` when the device is not accessible due to IP address
misconfiguration.
"""
AddressInfo.address.__doc__ = """
:str: IP address string for IP connections, or the device serial number for
plug & play.
"""
AddressInfo.slot_index.__doc__ = """
:Optional[int]: For clusters, this specifies which specific module to connect
to, if any. If None, the whole cluster will be treated as a single instrument.
"""
AddressInfo.scpi_port.__doc__ = """
:int: The port number for SCPI connections.
"""
AddressInfo.cfg_port.__doc__ = """
:int: The port number for configuration manager connections.
"""
AddressInfo.zmq_rr_port.__doc__ = """
:int: The port number for Qblox native ZeroMQ/CBOR REQ-REP connections.
"""
AddressInfo.zmq_ps_port.__doc__ = """
:int: The port number for Qblox native ZeroMQ/CBOR PUB-SUB connections.
"""
# -- functions ---------------------------------------------------------------
def _populate_ports(
protocol: str, address: str, slot_index: Optional[int]
) -> AddressInfo:
"""
Helper function for resolve(). Populates an :class:`~AddressInfo`
structure with port information.
Parameters
----------
protocol: str
Protocol, as determined by resolve().
address: str
IP address, as determined by resolve().
slot_index: Optional[int]
Slot index to retrieve port numbers for, or None to get the default
port numbers.
Returns
-------
AddressInfo
The completed address information structure.
"""
if slot_index is None or slot_index == CMM_SLOT_INDEX:
return AddressInfo(
protocol,
address,
slot_index,
MAIN_SCPI_PORT,
MAIN_CFG_PORT,
MAIN_ZMQ_RR_PORT,
MAIN_ZMQ_PS_PORT,
)
else:
return AddressInfo(
protocol,
address,
slot_index,
MODULE_SCPI_PORT_OFFSET + slot_index,
MODULE_CFG_PORT_OFFSET + slot_index,
MODULE_ZMQ_RR_PORT_OFFSET + slot_index,
MODULE_ZMQ_PS_PORT_OFFSET + slot_index,
)
# ----------------------------------------------------------------------------
[docs]
def resolve(identifier: Union[str, AddressInfo]) -> AddressInfo:
"""
Converts a device identifier to an IP address or (if only reachable via
plug and play) a serial number. For IP connections, also returns the ports
that the device should be listening on.
Parameters
----------
identifier: Union[str, AddressInfo]
If a string, this can be one of the following things:
- ``"[ip://]<ip-address>[/#]"``,
- ``"[pnp://]<device-name>[/#]"``,
- ``"[pnp://]<serial-number>[/#]"``, or
- ``"[ip://]<hostname>[/#]"``,
where:
- ``<ip-address>`` is a valid IPv4 or IPv6 address for the device to
be resolved;
- ``<device-name>`` is the customer-specified name of the instrument
(programmed into it with qblox-cfg, qblox-pnp, or the
``set_name()`` method);
- ``<serial-number>`` is the serial number of the instrument;
- ``<hostname>`` is a hostname that will resolve to the IP address of
the instrument via DNS (some routers support this if the device
connects via DHCP; the hostname requested by the device will be its
customer-specified name in lowercase, using dashes (``-``) for
sequences of non-alphanumeric characters);
- either ``ip://`` or ``pnp://`` may be prefixed to disambiguate
between the various methods of device identification, if necessary;
and
- the optional ``/#`` suffix may be used for cluster devices to
return information for a specific cluster module, where ``#`` is
the slot index of the module.
The four identification methods will be attempted in the sequence
shown.
If an :class:`~AddressInfo` object is passed as input, this function
simply returns it as-is.
Returns
-------
AddressInfo
Address information structure.
Raises
------
ValueError
If the identifier is invalid.
RuntimeError
If we failed to determine what this identifier is.
"""
# Fallthrough if input is already a resolved address.
if isinstance(identifier, AddressInfo):
return identifier
# Store the full identifier string for error messages.
full_identifier = identifier
# Properly log what we're doing.
logger = logging.getLogger("resolver")
logger.info('Resolving device identifier "%s"...', full_identifier)
# Split off slot index suffix, if specified.
if re.match(".*/[0-9]+$", identifier):
identifier, slot_index = identifier.rsplit("/", maxsplit=1)
slot_index = int(slot_index)
logger.info("Restricting connection to module in slot %d only.", slot_index)
else:
slot_index = None
# Split off protocol hint.
*hint, identifier = identifier.split("://", maxsplit=1)
if hint:
hint = hint[0]
if hint not in ("pnp", "ip"):
raise ValueError("protocol hint prefix must be pnp:// or ip://")
else:
hint = None
# See if this is an IP address.
if hint != "pnp":
try:
# Below line will throw a parse error if identifier is not a valid
# IP address.
ipaddress.ip_address(identifier)
# No error, so this is an IP address.
logger.info(
'"%s" is a valid IP address; skipping name resolution.', identifier
)
return _populate_ports("ip", identifier, slot_index)
except ValueError:
pass
# See if we can reach this device via plug & play.
if hint != "ip":
logger.info(
'Trying to resolve "%s" as device name or serial number '
"via plug & play...",
identifier,
)
data = None
try:
with PlugAndPlay() as p:
data = p.describe(identifier)
except Exception:
pass
if data is not None:
remote_ip = data.get("identity", {}).get("ip", None)
local_ip_and_prefix = data.get("connected_via", None)
if remote_ip is not None and local_ip_and_prefix is not None:
local_net = ipaddress.IPv4Network(local_ip_and_prefix, strict=False)
remote_net = ipaddress.IPv4Network(f"{remote_ip}/32", strict=False)
if local_net.overlaps(remote_net):
# Resolved via plug & play, but device should be
# accessible via regular TCP connections.
logger.info(
'Found "%s" at IP address %s via plug & play',
identifier,
remote_ip,
)
return _populate_ports("ip", remote_ip, slot_index)
else:
# IP misconfiguration, only plug & play is available. Use
# serial number instead of whatever the device responded
# to if possible.
logger.warning(
'Found "%s" at IP address %s via %s, but that won\'t '
"work; only plug & play connectivity is available",
identifier,
remote_ip,
local_ip_and_prefix,
)
address = data.get("identity", {}).get("ser", identifier)
return _populate_ports("pnp", address, slot_index)
# See if we can resolve the identifier via DNS.
if hint != "pnp":
logger.info('Trying to resolve "%s" via DNS lookup...', identifier)
try:
# Below line will throw a parse error if identifier is not a valid
# IP address.
data = socket.getaddrinfo(identifier, None)
if data:
remote_ip = data[0][4][0]
logger.info(
'Found "%s" at IP address %s via DNS lookup', identifier, remote_ip
)
return _populate_ports("ip", remote_ip, slot_index)
except OSError:
pass
raise RuntimeError(
f'Failed to resolve "{full_identifier}" as something we can connect to'
)
