Previously, the prober was stateless, and probe needed to be called manually whenever additional
probes were required. This adds a stateful prober, which can theoretically reuse clients
between runs and have smarter strategies for delays between retries, which may be crucial
depending on how slow UPnP is.
Signed-off-by: julianknodt <julianknodt@gmail.com>
* move probing out of netcheck into new net/portmapper package
* use PCP ANNOUNCE op codes for PCP discovery, rather than causing
short-lived (sub-second) side effects with a 1-second-expiring map +
delete.
* track when we heard things from the router so we can be less wasteful
in querying the router's port mapping services in the future
* use portmapper from magicsock to map a public port
Fixes#1298Fixes#1080Fixes#1001
Updates #864
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
