Optimize Darwin process finder

experimental/libbox/connection_owner_darwin.go

@@ -0,0 +1,57 @@
+package libbox
+
+import (
+	"net/netip"
+	"os/user"
+	"syscall"
+
+	"github.com/sagernet/sing-box/common/process"
+	E "github.com/sagernet/sing/common/exceptions"
+	F "github.com/sagernet/sing/common/format"
+)
+
+func FindConnectionOwner(ipProtocol int32, sourceAddress string, sourcePort int32, destinationAddress string, destinationPort int32) (*ConnectionOwner, error) {
+	source, err := parseConnectionOwnerAddrPort(sourceAddress, sourcePort)
+	if err != nil {
+		return nil, E.Cause(err, "parse source")
+	}
+	destination, err := parseConnectionOwnerAddrPort(destinationAddress, destinationPort)
+	if err != nil {
+		return nil, E.Cause(err, "parse destination")
+	}
+	var network string
+	switch ipProtocol {
+	case syscall.IPPROTO_TCP:
+		network = "tcp"
+	case syscall.IPPROTO_UDP:
+		network = "udp"
+	default:
+		return nil, E.New("unknown protocol: ", ipProtocol)
+	}
+	owner, err := process.FindDarwinConnectionOwner(network, source, destination)
+	if err != nil {
+		return nil, err
+	}
+	result := &ConnectionOwner{
+		UserId:      owner.UserId,
+		ProcessPath: owner.ProcessPath,
+	}
+	if owner.UserId != -1 && owner.UserName == "" {
+		osUser, _ := user.LookupId(F.ToString(owner.UserId))
+		if osUser != nil {
+			result.UserName = osUser.Username
+		}
+	}
+	return result, nil
+}
+
+func parseConnectionOwnerAddrPort(address string, port int32) (netip.AddrPort, error) {
+	if port < 0 || port > 65535 {
+		return netip.AddrPort{}, E.New("invalid port: ", port)
+	}
+	addr, err := netip.ParseAddr(address)
+	if err != nil {
+		return netip.AddrPort{}, err
+	}
+	return netip.AddrPortFrom(addr.Unmap(), uint16(port)), nil
+}