From: Guus Sliepen <guus@tinc-vpn.org>
Date: Wed, 23 Dec 2009 18:22:06 +0000 (+0100)
Subject: Do not fragment packets smaller than RFC defined minimum MTUs.
X-Git-Tag: release-1.0.12~17
X-Git-Url: https://git.librecmc.org/?p=oweals%2Ftinc.git;a=commitdiff_plain;h=43e34d8180c90682ed1601dec3de7f68ec96d65b;hp=43e34d8180c90682ed1601dec3de7f68ec96d65b

Do not fragment packets smaller than RFC defined minimum MTUs.

For IPv6, the minimum MTU is 1280 (RFC 2460), for IPv4 the minimum is actually
68, but this is such a low limit that it will probably hurt performance, so we
do as if it is 576 (the minimum packet size hosts should be able to handle, RFC
791). If we detect a path MTU smaller than those minima, and we have to handle
a packet that is bigger than the PMTU but smaller than those minima, we forward
them via TCP instead of fragmenting or returning ICMP packets.
---