The test-vconn program binds a socket to a nonspecific port number. To
add SSL support to this program, it needs to be able to use SSL, and the
stream library is the easiest way to do that. But the stream library
can't bind to a nonspecific port. This commit adds that feature, by adding
it to the function that the stream SSL library uses as a building block.
The tcp_open_active() and tcp_open_passive() functions don't really have
any strong dependencies on TCP. With a couple of simple changes they
can be used for UDP also. Since this is useful for Netflow, this commit
does so.
The TCP and SSL vconn implementations had a lot of common code to make
and accept TCP connections, which this commit factors out into common
functions in socket-util.c.
Also adds the ability to bind ptcp and pssl vconns to a particular IP
address instead of the wildcard address.
