ip_reass() fails to reassemble fragmented out-of-order traffic

[Eugene Grosbein]

Hi!

For long time I suffer from RELENG_8's inability to reassemble several types
of incoming fragmented packets when they arrive of-of-order.

For example: my gif(4) interface has MTU=1500, so it gets fragmented
when it goes out to the Internet. For some reason, in this setup 80% get reordered
while traveling the Internet. tcpdump shows me that at receiving side.

While I send these packets, sysctl net.inet.ip.fragpackets increases at receiving side.

No one reordered packet get reassembled. Some packet's fragments arrive in order
and those get reassembled just fine and tcpdump shows them at receiving gif interface,
and only them.

Note, there is no such problem for ICMP fragmented packets in this setup,
IPIP fragments are affected only.

Please help.

Eugene Grosbein.