GitLab

* commit 'a1067c8d':
  Improve error return values on network selection.

* commit 'e8164ddc':
  Fix MSS clamping.

It's very confusing to see EPERM when opening or connecting a
socket when the problem is not security-related. In the (common)
case where an app cannot select a network because it does not
exist, return ENONET ("Machine is not on network") instead.

Also, return EREMOTEIO for when we can't figure out who the user
is, and use EPERM for VPN denials and EACCES for permission
bits.

Bug: 17702933
Change-Id: Ia680c485e0ea1efad1ad374231d994e9bfd4cd5a

http://ag/553410 added an iptables chain and rule to do MSS
clamping for tethered clients, but did not add the chain to any
other chains, so the rule had no effect.

Fix this by adding the chain to the proper forwarding chains.
Also rename some of the new variables and constants so they are
more consistent with the previous code.

Bug: 17552732
Bug: 17727533
Change-Id: I9fcae31de5c0283d7d9f1dac989de84f77c5e53c

Bug: 17408011

Change-Id: I558270f1ce2603f305d38ad8604379ea533f0a47
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>

With this change, IPv4 tethering clients (such as PC) with default
MTU size 1500 will be configured again in the phone to use MTU
matching the carrier network, then no IP fragemention in the phone
and have higher data throughput for tethering.

bug:17552732
Change-Id: Ia306b1b8454da1b0e2d9c320e770aeff172d5fc4