platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/trafficmode/autolocal.go

@@ -0,0 +1,128 @@
+package trafficmode
+
+import (
+	"net/netip"
+	"sort"
+	"strings"
+)
+
+var cgnatPrefix = netip.MustParsePrefix("100.64.0.0/10")
+
+type AutoLocalRoute struct {
+	Dst string
+	Dev string
+}
+
+func ParseAutoBypassRoutes(mainRoutes string, vpnIface string, isVPNLikeIface func(string) bool) []AutoLocalRoute {
+	vpnIface = strings.TrimSpace(vpnIface)
+	seen := map[string]struct{}{}
+	routes := make([]AutoLocalRoute, 0, 8)
+
+	add := func(dst, dev string) {
+		dst = strings.TrimSpace(dst)
+		dev = strings.TrimSpace(dev)
+		if dst == "" || dev == "" {
+			return
+		}
+		key := dst + "|" + dev
+		if _, ok := seen[key]; ok {
+			return
+		}
+		seen[key] = struct{}{}
+		routes = append(routes, AutoLocalRoute{Dst: dst, Dev: dev})
+	}
+
+	for _, raw := range strings.Split(mainRoutes, "\n") {
+		line := strings.TrimSpace(raw)
+		if line == "" {
+			continue
+		}
+		if RouteLineIsLinkDown(line) {
+			continue
+		}
+		fields := strings.Fields(line)
+		if len(fields) == 0 {
+			continue
+		}
+		dst := strings.TrimSpace(fields[0])
+		if dst == "" || dst == "default" {
+			continue
+		}
+		dev := ParseRouteDevice(fields)
+		if dev == "" || dev == "lo" {
+			continue
+		}
+		if vpnIface != "" && dev == vpnIface {
+			continue
+		}
+		if isVPNLikeIface != nil && isVPNLikeIface(dev) {
+			continue
+		}
+
+		isScopeLink := strings.Contains(" "+line+" ", " scope link ")
+		if isScopeLink || IsContainerIface(dev) || IsAutoBypassDestination(dst) {
+			add(dst, dev)
+		}
+	}
+
+	sort.Slice(routes, func(i, j int) bool {
+		if routes[i].Dev == routes[j].Dev {
+			return routes[i].Dst < routes[j].Dst
+		}
+		return routes[i].Dev < routes[j].Dev
+	})
+	return routes
+}
+
+func ParseRouteDevice(fields []string) string {
+	for i := 0; i+1 < len(fields); i++ {
+		if fields[i] == "dev" {
+			return strings.TrimSpace(fields[i+1])
+		}
+	}
+	return ""
+}
+
+func IsContainerIface(iface string) bool {
+	l := strings.ToLower(strings.TrimSpace(iface))
+	return strings.HasPrefix(l, "docker") ||
+		strings.HasPrefix(l, "br-") ||
+		strings.HasPrefix(l, "veth") ||
+		strings.HasPrefix(l, "svh") ||
+		strings.HasPrefix(l, "svn") ||
+		strings.HasPrefix(l, "cni")
+}
+
+func RouteLineIsLinkDown(line string) bool {
+	l := " " + strings.ToLower(strings.TrimSpace(line)) + " "
+	return strings.Contains(l, " linkdown ")
+}
+
+func IsPrivateLikeAddr(a netip.Addr) bool {
+	if !a.Is4() {
+		return false
+	}
+	if a.IsPrivate() || a.IsLoopback() || a.IsLinkLocalUnicast() {
+		return true
+	}
+	return cgnatPrefix.Contains(a)
+}
+
+func IsAutoBypassDestination(dst string) bool {
+	dst = strings.TrimSpace(dst)
+	if dst == "" || dst == "default" {
+		return false
+	}
+	if strings.Contains(dst, "/") {
+		pfx, err := netip.ParsePrefix(dst)
+		if err != nil {
+			return false
+		}
+		return IsPrivateLikeAddr(pfx.Addr())
+	}
+	addr, err := netip.ParseAddr(dst)
+	if err != nil {
+		return false
+	}
+	return IsPrivateLikeAddr(addr)
+}