diff options
Diffstat (limited to 'net/interfaces/interfaces_windows.go')
| -rw-r--r-- | net/interfaces/interfaces_windows.go | 108 |
1 files changed, 64 insertions, 44 deletions
diff --git a/net/interfaces/interfaces_windows.go b/net/interfaces/interfaces_windows.go index 19e9b48b4..91f679c97 100644 --- a/net/interfaces/interfaces_windows.go +++ b/net/interfaces/interfaces_windows.go @@ -7,17 +7,19 @@ package interfaces import ( "fmt" "log" + "net" "net/url" - "os/exec" "syscall" "unsafe" - "go4.org/mem" "golang.org/x/sys/windows" "golang.zx2c4.com/wireguard/windows/tunnel/winipcfg" "inet.af/netaddr" "tailscale.com/tsconst" - "tailscale.com/util/lineread" +) + +const ( + fallbackInterfaceMetric = uint32(0) // Used if we cannot get the actual interface metric ) func init() { @@ -25,58 +27,76 @@ func init() { getPAC = getPACWindows } -/* -Parse out 10.0.0.1 from: - -Z:\>route print -4 -=========================================================================== -Interface List - 15...aa 15 48 ff 1c 72 ......Red Hat VirtIO Ethernet Adapter - 5...........................Tailscale Tunnel - 1...........................Software Loopback Interface 1 -=========================================================================== - -IPv4 Route Table -=========================================================================== -Active Routes: -Network Destination Netmask Gateway Interface Metric - 0.0.0.0 0.0.0.0 10.0.0.1 10.0.28.63 5 - 10.0.0.0 255.255.0.0 On-link 10.0.28.63 261 - 10.0.28.63 255.255.255.255 On-link 10.0.28.63 261 - 10.0.42.0 255.255.255.0 100.103.42.106 100.103.42.106 5 - 10.0.255.255 255.255.255.255 On-link 10.0.28.63 261 - 34.193.248.174 255.255.255.255 100.103.42.106 100.103.42.106 5 - -*/ func likelyHomeRouterIPWindows() (ret netaddr.IP, ok bool) { - cmd := exec.Command("route", "print", "-4") - cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true} - stdout, err := cmd.StdoutPipe() + rs, err := winipcfg.GetIPForwardTable2(windows.AF_INET) if err != nil { + log.Printf("routerIP/GetIPForwardTable2 error: %v", err) return } - if err := cmd.Start(); err != nil { + + var ifaceMetricCache map[winipcfg.LUID]uint32 + + getIfaceMetric := func(luid winipcfg.LUID) (metric uint32) { + if ifaceMetricCache == nil { + ifaceMetricCache = make(map[winipcfg.LUID]uint32) + } else if m, ok := ifaceMetricCache[luid]; ok { + return m + } + + if iface, err := luid.IPInterface(windows.AF_INET); err == nil { + metric = iface.Metric + } else { + log.Printf("routerIP/luid.IPInterface error: %v", err) + metric = fallbackInterfaceMetric + } + + ifaceMetricCache[luid] = metric return } - defer cmd.Wait() - var f []mem.RO - lineread.Reader(stdout, func(lineb []byte) error { - line := mem.B(lineb) - if !mem.Contains(line, mem.S("0.0.0.0")) { - return nil + unspec := net.IPv4(0, 0, 0, 0) + var best *winipcfg.MibIPforwardRow2 // best (lowest metric) found so far, or nil + + for i := range rs { + r := &rs[i] + if r.Loopback || r.DestinationPrefix.PrefixLength != 0 || !r.DestinationPrefix.Prefix.IP().Equal(unspec) { + // Not a default route, so skip + continue } - f = mem.AppendFields(f[:0], line) - if len(f) < 3 || !f[0].EqualString("0.0.0.0") || !f[1].EqualString("0.0.0.0") { - return nil + + ip, ok := netaddr.FromStdIP(r.NextHop.IP()) + if !ok { + // Not a valid gateway, so skip (won't happen though) + continue } - ipm := f[2] - ip, err := netaddr.ParseIP(string(mem.Append(nil, ipm))) - if err == nil && isPrivateIP(ip) { + + if best == nil { + best = r ret = ip + continue } - return nil - }) + + // We can get here only if there are multiple default gateways defined (rare case), + // in which case we need to calculate the effective metric. + // Effective metric is sum of interface metric and route metric offset + if ifaceMetricCache == nil { + // If we're here it means that previous route still isn't updated, so update it + best.Metric += getIfaceMetric(best.InterfaceLUID) + } + r.Metric += getIfaceMetric(r.InterfaceLUID) + + if best.Metric > r.Metric || best.Metric == r.Metric && ret.Compare(ip) > 0 { + // Pick the route with lower metric, or lower IP if metrics are equal + best = r + ret = ip + } + } + + if !ret.IsZero() && !isPrivateIP(ret) { + // Default route has a non-private gateway + return netaddr.IP{}, false + } + return ret, !ret.IsZero() } |