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#
# Copyright 2017 Ettus Research, a National Instruments Company
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
"""Code to run the discovery port.
"""
import socket
from multiprocessing import Process, current_process
from usrp_mpm.mpmlog import get_main_logger
from usrp_mpm.mpmtypes import MPM_DISCOVERY_PORT
from usrp_mpm.mpmutils import to_binary_str, set_proc_title
RESPONSE_PREAMBLE = b"USRP-MPM"
RESPONSE_SEP = b";"
RESPONSE_CLAIMED_KEY = b"claimed"
# A buffer size large enough to capture any UDP packet we receive on the
# discovery socket
MAX_SOCK_BUFSIZ = 9000
# For setsockopt
IP_MTU_DISCOVER = 10
IP_PMTUDISC_DO = 2
def spawn_discovery_process(shared_state, discovery_addr):
"""Returns a process that contains the device discovery.
:param shared_state: Shared state of device (is it claimed, etc.).
Is a SharedState() object.
:param discovery_addr: Discovery will listen on this address(es)
"""
proc = Process(target=_discovery_process, name="Discovery", args=(shared_state, discovery_addr))
proc.start()
return proc
def _discovery_process(state, discovery_addr):
"""The actual process for device discovery.
Is spawned by spawn_discovery_process().
"""
log = get_main_logger().getChild("discovery")
set_proc_title(current_process().name, log)
def create_response_string(state):
"""Generate the string that gets sent back to the requester.
Uses state to generate a human-readable string that describes the
device.
:param state: The shared state of the device.
"""
return RESPONSE_SEP.join(
[RESPONSE_PREAMBLE]
+ [b"type=" + state.dev_type.value]
+ [b"product=" + state.dev_product.value]
+ [b"serial=" + state.dev_serial.value]
+ [b"name=" + state.dev_name.value]
+ [b"fpga=" + state.dev_fpga_type.value]
+ [RESPONSE_CLAIMED_KEY + to_binary_str("={}".format(state.claim_status.value))]
)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# FIXME really, we should only bind to the subnet but I haven't gotten that
# working yet
sock.bind((("0.0.0.0", MPM_DISCOVERY_PORT)))
sock.setsockopt(socket.IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DO)
# TODO yeah I know that's not how you do this
discovery_addr_prefix = discovery_addr.replace(".255", "")
if discovery_addr == "0.0.0.0":
discovery_addr_prefix = ""
try:
while True:
data, sender = sock.recvfrom(MAX_SOCK_BUFSIZ)
log.debug("Got poked by: %s", sender[0])
# TODO this is still part of the awful subnet identification
if not sender[0].startswith(discovery_addr_prefix):
continue
if data.strip(b"\0") == b"MPM-DISC":
log.debug("Sending discovery response to %s port: %d", sender[0], sender[1])
resp_str = create_response_string(state)
send_data = resp_str
log.trace("Return data: %s", send_data)
sock.sendto(send_data, sender)
elif data.startswith(b"MPM-ECHO"):
log.debug(
"Received echo request ({len} bytes) from {sender}".format(
len=len(data), sender=sender[0]
)
)
send_data = data
try:
sock.sendto(send_data, sender)
except OSError as ex:
log.debug("ECHO send error: %s", str(ex))
except Exception as err:
log.error("Unexpected error: `%s' Type: `%s'", str(err), type(err))
sock.close()
exit(1)
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