[Kea-users] KEA handling malformed packets

[Marcin Jurczuk]

Hi,
Kea migration story continues :)

I have lab system with isc-dhcp-server and kea installed.
I stuck on issue of handling malformed packets.
ISC-DHCP handles them flawlesly yet kea throws weird error:
DEBUG DHCP4_LEASE_QUERY_PACKET_UNPACK_FAILED failed to parse query from
10.0.0.1 to 172.16.0.10, received over interface ens18, reason: Option
parse failed. Tried to parse 161 bytes from 158-byte long buffer.

This is not LEASE QUERY packet at all. pcap shows this is malformed packet
where option125 length reported by CableModem is just wrong.
Below is wireshark text about exactly that packet that causes problem - it
was captured on dhcpd server.

To emphasise - turning off kea, starting isc-dhcp - and modem gets IP,
turning off isc-dhcp enabling kea - I'm getting this error and modem is not
getting IP.

---------------
Dynamic Host Configuration Protocol (Discover)
Message type: Boot Request (1)
Hardware type: Ethernet (0x01)
Hardware address length: 6
Hops: 1
Transaction ID: 0x7f9762fa
Seconds elapsed: 0
Bootp flags: 0x0000 (Unicast)
Client IP address: 0.0.0.0
Your (client) IP address: 0.0.0.0
Next server IP address: 0.0.0.0
Relay agent IP address: 10.0.0.1
Client MAC address: CompalBroadb_de:de:58 (90:5c:44:de:de:58)
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (Discover)
Length: 1
DHCP: Discover (1)
Option: (60) Vendor class identifier
Option: (0) Padding
Option: (61) Client identifier
Length: 15
IAID: 44dede58
DUID Type: link-layer address (3)
Hardware type: Ethernet (1)
Link layer address: 90:5c:44:de:de:58
Link layer address (Ethernet): CompalBroadb_de:de:58 (90:5c:44:de:de:58)
Option: (125) V-I Vendor-specific Information
Length: 162
Enterprise: Cable Television Laboratories, Inc. (4491)
Length: 157
Option 125 Suboption: (124) Unknown
Option 125 Suboption: (1) Option Request
Option 125 Suboption: (5) Modem Capabilities
Length: 150
[Malformed Packet: DHCP/BOOTP: length of contained item exceeds length of
containing item]
[Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]
[Malformed Packet (Exception occurred)]
[Severity level: Error]
[Group: Malformed]

Thanks in advance
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