Submission type

Bug report

systemd version

232-25

Used distribution

Debian 9.0

Expected behavior

• networkctl lldp shows information taken from LLDP messages containing padding after EndOfLLDPDUTLV, see note in standard IEEE Std 802.1AB-2016, p. 42, sec. 8.5.1:

For example, the IEEE 802.3 MAC adds pad octets to complete a minimum length data field if the 
user’s data is less than the minimum required length. Since pad octets are unspecified, an End Of  
LLDPDU TLV can be used to prevent non-zero pad octets from being interpreted by the receiving 
LLDP agent as another TLV.

Unexpected behavior

• LLDP messages containing padding after EndOfLLDPDUTLV are ignored/dropped

Steps to reproduce the problem

• configure interface X to accept LLDP reports
• switch interface to promiscuous mode (AFAIK already covered by another issue)
• send short LLDP DU ( < 60 bytes, just ChassisID = 'A' / PortID = 'B', TTL and EndOfTLV - no capabilities TLV - padding applied) from external device to interface X (see lldp-with-padding.pcapng.base64.txt - contains 32 bytes padding after EndOfTLV)
• networkctl lldp shows no entry for ChassisID = 'A' / PortID = 'B' ...
• replay trace lldp-no-padding.pcapng.base64.txt
  -> entry ChassisID ='A01234567890123456789012345678901' / PortID = 'B' present