Commit Graph

3 Commits (affd859121e331624af53fcc76363ba93949efde)

Author SHA1 Message Date
David Crawshaw d139fa9c92 net/interfaces: use a uint32_t for ipv4 address
The code was using a C "int", which is a signed 32-bit integer.
That means some valid IP addresses were negative numbers.
(In particular, the default router address handed out by AT&T
fiber: 192.168.1.254. No I don't know why they do that.)
A negative number is < 255, and so was treated by the Go code
as an error.

This fixes the unit test failure:

	$ go test -v -run=TestLikelyHomeRouterIPSyscallExec ./net/interfaces
	=== RUN   TestLikelyHomeRouterIPSyscallExec
	    interfaces_darwin_cgo_test.go:15: syscall() = invalid IP, false, netstat = 192.168.1.254, true
	--- FAIL: TestLikelyHomeRouterIPSyscallExec (0.00s)

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
4 years ago
Josh Bleecher Snyder a9b1e3f9e8 net/interfaces: remove old debug old
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
4 years ago
Josh Bleecher Snyder a16a793605 net/interfaces: use syscalls to find private gateway IP address
iOS doesn't let you run subprocesses,
which means we can't use netstat to get routing information.
Instead, use syscalls and grub around in the results.
We keep the old netstat version around,
both for use in non-cgo builds,
and for use testing the syscall-based version.

Note that iOS doesn't ship route.h,
so we include a copy here from the macOS 10.15 SDK
(which is itself unchanged from the 10.14 SDK).

I have tested manually that this yields the correct
gateway IP address on my own macOS and iOS devices.
More coverage would be most welcome.

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
4 years ago