Added bind_device_by_index_{v4,v6} for linux and android (#569)

[boris-n]

No description provided.

[ningyuan-wang]

For Android and Linux, the syscalls are independent of the V4 or V6 stack used, therefore the function name should be bind_device_by_index, and not having the suffix attached.

Since setsockopt for SO_BINDTOIFINDEX is added, the corresponding getsockopt is also needed.

Android support required a bump to libc version: See 0.2.172 updates for libc.

PR 573 is created that resolves the issues listed.

[boris-n]

For Android and Linux, the syscalls are independent of the V4 or V6 stack used, therefore the function name should be bind_device_by_index, and not having the suffix attached.

The question here is mainly if the socket2 library should provide an abstraction from the target OS (as far as possible) or provide a different set of functions for each target OS.

I leave it to the maintainers of the socket2 library to make this decision.

Since setsockopt for SO_BINDTOIFINDEX is added, the corresponding getsockopt is also needed.

Added. (Again, a decision from the socket2 maintainers is needed if this should be added to the existing device_index_{v4,v6} functions, or if a new, IP version independent function should be added for linux/android.

Android support required a bump to libc version: See 0.2.172 updates for libc.

Updated.

[boris-n]

For Android and Linux, the syscalls are independent of the V4 or V6 stack used, therefore the function name should be bind_device_by_index, and not having the suffix attached.

The question here is if the socket2 library should provide functions which abstract from the target OS (as far as possible) or if it should provide target OS specific functions. I.e. do we want to have bind_device_by_index_{v4,v6} for some targets and bind_device_by_index for Linux/Android, or do we want to have a single set of functions for all target OSes.

I leave it to the maintainer of the socket2 library to make this decision.

Since setsockopt for SO_BINDTOIFINDEX is added, the corresponding getsockopt is also needed.

Added. (Same as above: A decision is needed if we want to have device_index_{v4,v6} functions for some target OS and device_index function for Linux/Android or if we want to have a single set of functions for all target OSes.)

Android support required a bump to libc version: See 0.2.172 updates for libc.

Updated.