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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2025 Daniel Estevez <daniel@destevez.net>
#
# This file is part of gr-satellites
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
import pmt
from gnuradio import gr
class csp_address_filter(gr.sync_block):
"""CSP Address Filter block"""
def __init__(self, allowed_sources, allowed_destinations):
gr.sync_block.__init__(
self,
name='csp_address_filter',
in_sig=[],
out_sig=[]
)
self.sources = allowed_sources
self.destinations = allowed_destinations
self.message_port_register_in(pmt.intern('in'))
self.set_msg_handler(pmt.intern('in'), self.handle_msg)
self.message_port_register_out(pmt.intern('out'))
def handle_msg(self, msg_pmt):
msg = pmt.cdr(msg_pmt)
if not pmt.is_u8vector(msg):
print('[ERROR] received invalid message type. Expected u8vector')
return
msg = pmt.u8vector_elements(msg)
if len(msg) < 4:
print('[csp_address_filter] message is too short')
return
# extract addresses from CSP header
source = (msg[0] >> 1) & 0x1f
destination = ((msg[0] & 1) << 4) | (msg[1] >> 4)
if source not in self.sources or destination not in self.destinations:
# drop packet
return
self.message_port_pub(pmt.intern('out'), msg_pmt)
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