zebra: use SO_RCVBUFFORCE for netlink socket

so net.core.rmem_max must not be adjusted. Requires
linux kernel >= 2.6.14, falls back to SO_RCVBUF on error

Signed-off-by: Ulrich Weber <ulrich.weber@sophos.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
2 files changed