net/portmapper: handle multiple UPnP discovery responses

[andrew-d]

Instead of taking the first UPnP response we receive and using that to create port mappings, store all received UPnP responses, sort and deduplicate them, and then try all of them to obtain an external address.

Updates #10602

Change-Id: I783ccb1834834ee2a9ecbae2b16d801f2354302f

[andrew-d]

Reviewer note: the diff doesn't do a good job at capturing it, but there's not as much code changed as it seems. Most of tryUPnPPortmapWithDevice is just extracted from getUPnPPortMapping for clarity, and the test changes are mostly whitespace and indenting inside a loop.

[sailorfrag]

Do we try to make a permanent lease? I think it would be better to always try to make one that expires.

[andrew-d]

We always try a temporary lease first, but some UPnP implementations don't support that. In those cases, we fall back to a permanent lease, though we still explicitly remove that lease when we're not using it.

[andrew-d]

Switched away from a channel to an atomic.Bool since we didn't actually use the channel for anything other than signalling; mind taking another quick look, @jwhited and/or @sailorfrag?

[andrew-d]

Testing notes: tested on a networking running an eero device as the main router, along with a network running a Linux server with MiniUPnPd 2.3.3 as the router. Both networks were still able to obtain a portmap, and on the second network, deduplicated the returned UPnP responses successfully:

portmapper: UPnP reply {Location:http://192.168.X.Y:1234/rootDesc.xml Server:Linux/6.99.99 UPnP/1.1 MiniUPnPd/2.3.3 USN:uuid:aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee::urn:schemas-upnp-org:device:InternetGatewayDevice:2}, "HTTP/1.1 200 OK\r\nCACHE-CONTROL: max-age=120\r\nST: urn:schemas-upnp-org:device:InternetGatewayDevice:2\r\nUSN: uuid:aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee::urn:schemas-upnp-org:device:InternetGatewayDevice:2\r\nEXT:\r\nSERVER: Linux/6.99.99 UPnP/1.1 MiniUPnPd/2.3.3\r\nLOCATION: http://192.168.X.Y:1234/rootDesc.xml\r\nOPT: \"http://schemas.upnp.org/upnp/1/0/\"; ns=01\r\n01-NLS: 12345\r\nBOOTID.UPNP.ORG: 12345\r\nCONFIGID.UPNP.ORG: 1337\r\n\r\n"
portmapper: UPnP reply {Location:http://192.168.X.Y:1234/rootDesc.xml Server:Linux/6.99.99 UPnP/1.1 MiniUPnPd/2.3.3 USN:uuid:aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee::urn:schemas-upnp-org:device:InternetGatewayDevice:1}, "HTTP/1.1 200 OK\r\nCACHE-CONTROL: max-age=120\r\nST: urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\nUSN: uuid:aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee::urn:schemas-upnp-org:device:InternetGatewayDevice:1\r\nEXT:\r\nSERVER: Linux/6.99.99 UPnP/1.1 MiniUPnPd/2.3.3\r\nLOCATION: http://192.168.X.Y:1234/rootDesc.xml\r\nOPT: \"http://schemas.upnp.org/upnp/1/0/\"; ns=01\r\n01-NLS: 12345\r\nBOOTID.UPNP.ORG: 12345\r\nCONFIGID.UPNP.ORG: 1337\r\n\r\n"
portmapper: UPnP meta changed: [{Location:http://192.168.X.Y:1234/rootDesc.xml Server:Linux/6.99.99 UPnP/1.1 MiniUPnPd/2.3.3 USN:uuid:aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee::urn:schemas-upnp-org:device:InternetGatewayDevice:2}]