excluding USRP packets by parse, pcap extraction of single-fragment-lc and vbptc32,11, release v0.5

Author: smarek

okdmr/dmrlib/tools/pcap_tool.py

@@ -7,6 +7,7 @@
 
 from bitarray import bitarray
 from kaitaistruct import KaitaiStruct
+from okdmr.dmrlib.etsi.fec.vbptc_32_11 import VBPTC3211
 from okdmr.kaitai.homebrew.mmdvm2020 import Mmdvm2020
 from okdmr.kaitai.hytera.ip_site_connect_heartbeat import IpSiteConnectHeartbeat
 from okdmr.kaitai.hytera.ip_site_connect_protocol import IpSiteConnectProtocol
@@ -43,10 +44,12 @@ def process_packet(self, data: bytes, packet: IP) -> Optional[FullLinkControl]:
             burst
             and burst.has_emb
             and burst.emb.link_control_start_stop == LCSS.SingleFragmentLCorCSBK
+            and burst.embedded_signalling_bits.count(1)
         ):
             print(
-                f"Single burst data for VBPTC 32,11 [{burst.emb.preemption_and_power_control_indicator}] {burst.embedded_signalling_bits}"
+                f"Single burst data for VBPTC 32,11 [{burst.emb.preemption_and_power_control_indicator}] on-air(fec protected) {burst.embedded_signalling_bits} (vbptc deinterleaved) {VBPTC3211.deinterleave_data_bits(burst.embedded_signalling_bits)} in {data.hex()}"
             )
+            return
 
         if (
             not burst

okdmr/dmrlib/utils/parsing.py

@@ -48,6 +48,12 @@ def parse_hytera_data(bytedata: bytes) -> KaitaiStruct:
 
 def try_parse_packet(udpdata: bytes) -> Optional[KaitaiStruct]:
 
+    try:
+        if udpdata[:4] == b"USRP":
+            return None
+    finally:
+        pass
+
     # Try MMDVM/Homebrew packets
     try:
         mmdvm = Mmdvm2020.from_bytes(udpdata)

okdmr/tests/dmrlib/etsi/fec/test_vbptc_32_11.py

@@ -15,6 +15,9 @@ def test_vbptc_sanity():
 def test_encode_decode_vbptc():
     bursts: List[(str,)] = [
         ("00000100010110000000100010100100",),
+        # following are not valid vbptc protected payloads, probably something proprietary / unidentified
+        # ("00001100000100010010010001000001",),
+        # ("00010111000010100000011001000100",),
     ]
 
     for (burst,) in bursts:

okdmr/tests/dmrlib/utils/test_parsing.py

@@ -53,3 +53,7 @@ def test_parsing_detection():
     mmdvm_hex: str = "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"
     pkt: KaitaiStruct = try_parse_packet(bytes.fromhex(mmdvm_hex))
     assert isinstance(pkt, Mmdvm2020)
+
+    usrp_hex: str = "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"
+    pkt: Optional[KaitaiStruct] = try_parse_packet(bytes.fromhex(usrp_hex))
+    assert pkt is None

setup.py

@@ -17,7 +17,7 @@
     author="Marek Sebera",
     author_email="marek.sebera@gmail.com",
     license="AGPL-3.0",
-    version="0.4",
+    version="0.5",
     packages=[
         "okdmr.dmrlib",
         "okdmr.dmrlib.transmission",