[bIackr0se]

Description

PNIORealTimeAcyclicPDUHeader declares PDUTypeType before PDUTypeVersion (pnio_rpc.py#L1356-L1357), so scapy reads the type from the high nibble of the PDUType octet. Wireshark (masks) and the rt-labs p-net stack (reader) put the type in bits 0-3 and the version in bits 4-7. A received RTA acknowledgement (0x13, ACK version 1) dissects as RTA_TYPE_DATA version 3, and Alarm_Low(PDUTypeType=3, PDUTypeVersion=1) writes 0x31, which Wireshark reads as a Data-RTA-PDU version 3. The existing tests do not check these two fields: the alarm captures use 0x11, where both orders agree, and the acknowledgement test uses 0x13 without asserting the type or version.

This PR swaps the two fields so the version is the high nibble.

from scapy.all import Ether, raw, load_contrib
load_contrib("pnio")
load_contrib("pnio_rpc")
from scapy.contrib.pnio_rpc import Alarm_Low
a = Alarm_Low(b'\x00\x03\x00\x03\x13\x00\x00\x00\xff\xff\x00\x00')
print(a.PDUTypeType, a.PDUTypeVersion)
print(raw(Alarm_Low(PDUTypeType=3, PDUTypeVersion=1))[4:5])

Before:

1 3
b'1'

After:

3 1
b'\x13'

tshark 4.6.9 decodes the PDUType of an Alarm_Low frame for each of the 256 octet values the same way scapy does after this change (before, only the 16 values with equal nibbles matched). A test is added to test/contrib/pnio_rpc.uts.

This message was written with the help of AI (Claude Opus 5.5).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.15%. Comparing base (0e2f6ba) to head (1ae8e54).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5297      +/-   ##
==========================================
+ Coverage   80.06%   80.15%   +0.08%     
==========================================
  Files         375      375              
  Lines       98775    98775              
==========================================
+ Hits        79083    79169      +86     
+ Misses      19692    19606      -86     

Files with missing lines	Coverage Δ
scapy/contrib/pnio_rpc.py	94.72% <ø> (ø)

... and 13 files with indirect coverage changes

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