Ability to obtain the default gateway

[silverwind]

I think it would be very useful to have a method on os which returns

• the default gateway of the machine, v4 and v6
• the default gateway's network interface name (if any)

Basically, something like @indutny's netroute but cross-platform. The ability to access this information seems critical for applications that do low-level things on the local network and I think this justifies its existance in core. My personal use case would be to automatically determine the right interface to do packet capture on.

Right now, the only way (without native modules) to obtain the information in a cross-platform way would be parsing the output of various commands, which is of course slow and error-prone.

@bnoordhuis: the request has been brought up in 2012 and you rejected it as bloat. Does this still stand?

cc: @sindresorhus (sindresorhus/internal-ip#5)

[bnoordhuis]

It would have to be implemented in libuv first and it would need to be generic enough to be useful. It should provide more than just the defaults and do something sane on multi-homed machines. Routing can be pretty complicated so there's a lot of potential for complexity.

[indutny]

@silverwind IMO, this is complicated non-obvious thing. Don't know if libuv may want to have it. Routing is hard.

[silverwind]

Yes, I see networkInterfaces as kind of borderline for libuv's purpose of being a IO library, this one may be too.

[jasnell]

Is there reason to keep this one open? given the responses it's not likely to be something we'll actually get. Perhaps open a feature request in libuv instead?

[silverwind]

I guess we can close it. It's still a desireable future in my eyes, but probably too hard to get right.