Discarded count not incremented for a malformed LLDP packet

[sriharshamadala]

Discarded count not incremented for a malformed LLDP packet

When I intentionally write an LLDP packet with zero-padded payload I see the received count incremented but not any of the other counters.

Steps to reproduce the problem

1. Create a tap interface:

ip tuntap add dev tap1 mode tap
ip link set dev tap1 up

2. launch the lldp in rx-only mode to listen to the Tap interface, like so:

lldpd -r -C tap1

3. Followed this tutorial to create a tap_client.c that writes a custom packet to the tap interface. The packet content is:

    lldp_packet_data_buffer[++ii] = htonl(0x0180c200);
    lldp_packet_data_buffer[++ii] = htonl(0x000e0080);
    lldp_packet_data_buffer[++ii] = htonl(0x1688309f);
    lldp_packet_data_buffer[++ii] = htonl(0x88cc0207);
    
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   
    lldp_packet_data_buffer[++ii] = htonl(0x00000000);
   

4. On another shell run the tcpdump command:

tcpdump -vvv -i tap1 'ether proto 0x88cc'

Expected outcome

I would expect the discarded count to be same as received count

Current outcome

discarded count is not incremented.

lldpcli show statistics

LLDP statistics:

Interface: tap1
Transmitted: 0
Received: 3
Discarded: 0
Unrecognized: 0
Ageout: 0
Inserted: 0
Deleted: 0

[vincentbernat]

Thanks for reporting! This has been fixed in 32f0dee.