The default MTU of 1500 is too high if kernel-libipsec is used (considering
the overhead of UDP-encapsulated ESP), but might also have an effect if
a TUN device is only used to install a virtual IP (the route points to it,
so the system might use its MTU and 1500 would still be too high).
This also works around an issue on macOS 12 where no RTM_IFINFO event
is sent for the newly created TUN device (neither for the creation,
setting it "up", nor adding the address). Changing the MTU, however,
triggers such an event and we can detect the virtual IP.
Closesstrongswan/strongswan#707
The main intention here is that we can change the hashtable_t
implementation without being impeded by the special requirements imposed
by get_match() and sorting the keys/items in buckets.
Enables us to ignore any future kernel features for routes unless
we actually need to consider them for the source IP routes.
Also enables us to actually really skip IPsec processing for those networks
(because even the routes don't touch those packets). It's more what
users expect.
Co-authored-by: Tobias Brunner <tobias@strongswan.org>
It seems that there is a race, at least in 10.13, that lets
if_indextoname() fail for the new TUN device. So we delay the call a bit,
which seems to "fix" the issue. It's strange anyway that the previous
delay was only applied when an iface entry was already found.
Tobias Brunner