Two years ago, Shan Wei tried to fix this:
http://patchwork.ozlabs.org/patch/43905/
The problem is that RFC2460 requires an ICMP Time
Exceeded -- Fragment Reassembly Time Exceeded message should be
sent to the source of that fragment, if the defragmentation
times out.
"
If insufficient fragments are received to complete reassembly of a
packet within 60 seconds of the reception of the first-arriving
fragment of that packet, reassembly of that packet must be
abandoned and all the fragments that have been received for that
packet must be discarded. If the first fragment (i.e., the one
with a Fragment Offset of zero) has been received, an ICMP Time
Exceeded -- Fragment Reassembly Time Exceeded message should be
sent to the source of that fragment.
"
As Herbert suggested, we could actually use the standard IPv6
reassembly code which follows RFC2460.
With this patch applied, I can see ICMP Time Exceeded sent
from the receiver when the sender sent out 3/4 fragmented
IPv6 UDP packet.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michal Kubeček <mkubecek@suse.cz>
Cc: David Miller <davem@davemloft.net>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
b836c99fd6