Re: [PATCH] tcp resets are misrouted

From: Alexey Kuznetsov <redacted>
Date: Fri, 12 Oct 2012 18:34:17 +0400

After commit e2446eaa.. tcp resets are always lost, when routing is asymmetric.
Yes, backing out that patch will result in misrouting of resets for dead connections
which used interface binding when were alive, but we actually cannot do anything here.
What's died that's died and correct handling normal unbound connections is obviously a priority.

Comment to comment:

quoted

This has few benefits:
  1. tcp_v6_send_reset already did that.

It was done to route resets for IPv6 link local addresses. It was a mistake to
do so for global addresses. The patch fixes this as well.

Actually, the problem appears to be even more serious than guaranteed loss of resets.
As reported by Sergey Soloviev [off-list ref], those misrouted resets create a lot of
arp traffic and huge amount of unresolved arp entires putting down to knees NAT firewalls
which use asymmetric routing.

Signed-off-by: Alexey Kuznetsov <redacted>

Applied and queued up for -stable, thanks!