net/tap: simplify netlink send/receive functions
net/tap: simplify netlink send/receive functions

The tap_nl_recv() function does not need to use the full
complex recvmsg() system call, basic recv() will work here.

Ditto for tap_nl_send() full sendmsg is not needed.

Add logic to retry in case EINTR rather than forcing
error handling back in driver or worse to ethdev API.

Signed-off-by: Stephen Hemminger <06fa905d7f2aaced6dc72e9511c71a2a51e8aead@networkplumber.org>
Acked-by: Keith Wiles <f97a07384723981b442bf4ce37d40edbfd008094@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk