ss: print MD5 signature keys configured on TCP sockets

These keys are reported by kernel 4.14 and later under the
INET_DIAG_MD5SIG attribute, when INET_DIAG_INFO is requested (ss -i)
and we have CAP_NET_ADMIN. The additional output looks like:

	md5keys:fe80::/64=signing_key,10.1.2.0/24=foobar,::1/128=Test

Signed-off-by: Ivan Delalande <colona@arista.com>
1 file changed