When this library was originally implemented, support for Linux 2.4 was
important. The Netlink implementation in Linux only added support for
joining and leaving multicast groups after a socket is bound as of Linux
2.6.14, so the library did not support it either. But the current version
of Open vSwitch targets Linux 2.6.18 and over, so it's fine to add this
support now, and this commit does so.
This will be used more extensively in upcoming commits.
Reviewed by Justin Pettit.
The parts of the netlink module that are related to sockets are
Linux-specific, since only Linux has AF_NETLINK sockets. The rest can be
built anywhere. This commit breaks them into two modules, and builds the
generic one on all platforms.
Acked-by: Jesse Gross <jesse@nicira.com>
