support domain substitutions

[scareything]

Adding some variables that are resolved when evaluating intercept.v1 dialOptions.identity would make it easier to support multiple remote networks. This follows from discussion on discourse.

Proposed variables

variable	description	example value
$dst_fqdn	the fqdn that was intercepted. this is a synonym for $dst_hostname, but $dst_fqdn seems more clear	"host1.region1.dc1.openziti.io"
$dst_host	the host portion of the intercepted fqdn	"host1"
$dst_domain	the domain portion of the intercepted fqdn	"openziti.io"
$dst_subdomain	the complete subdomain portion of $dst_fqdn	"region1.dc1"
$dst_subdomain[n]	the n'th subdomain (starting from the right) in $dst_subdomain	$dst_subdomain[0] == "dc1", $dst_subdomain[1] == "region1"
$dst_matched_wildcard	the wildcard domain if $dst_fqdn matches an intercepted wildcard domain	e.g. if wildcard is "*.dc1.openziti.io" then $dst_matched_wildcard == "dc1.openziti.io"

[jesse2point0]

To clarify, $dst_host would match output of the `hostname' command of a Device, correct? If so, PERFECT!

How would devices with no domain (p2p hosts) be identified beyond their hostname? A scenario might be that there are two hosts named frontdeskpc in two different networks. Is there any conflict? They can be further distinguished by subnet or tag or attributes?

[scareything]

It can be easy to forget that ziti "hostnames" are completely fictional as far as the hosts are concerned - that is unless you intentionally align the system hostnames with your ziti hostnames. When using $dst_hostname and the like, the ziti hostnames are just the addresses that you use to access other devices through the openziti overlay.

So you're free to line up system hostnames with ziti identities, but that alignment is really just a coincidence that you created (and probably need to maintain and keep straight). If you do this, and the hostnames are not sufficient to uniquely identify each device, then you'd probably quickly find that the openziti controller does not allow identities to have the same name.