Routing: process supports UID on Android (#5915)

Example: https://github.com/XTLS/Xray-core/pull/5915#issuecomment-4232122895

---------

Co-authored-by: 风扇滑翔翼 <Fangliding.fshxy@outlook.com>

common/net/find_process_android.go

@@ -0,0 +1,20 @@
+//go:build android
+
+package net
+
+import (
+	"github.com/xtls/xray-core/common/errors"
+)
+
+var androidProcessFinder func(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (int, string, string, error)
+
+func RegisterAndroidProcessFinder(f func(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (int, string, string, error)) {
+	androidProcessFinder = f
+}
+
+func FindProcess(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (int, string, string, error) {
+	if androidProcessFinder != nil {
+		return androidProcessFinder(network, srcIP, srcPort, destIP, destPort)
+	}
+	return 0, "", "", errors.New("android process lookup must be registered before use")
+}

common/net/find_process_linux.go

@@ -1,4 +1,4 @@
-//go:build linux
+//go:build linux && !android
 
 package net
 
@@ -6,6 +6,7 @@ import (
 	"bufio"
 	"encoding/hex"
 	"fmt"
+	"net"
 	"os"
 	"strconv"
 	"strings"
@@ -13,43 +14,38 @@ import (
 	"github.com/xtls/xray-core/common/errors"
 )
 
-func FindProcess(dest Destination) (PID int, Name string, AbsolutePath string, err error) {
-	isLocal, err := IsLocal(dest.Address.IP())
+func FindProcess(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (PID int, Name string, AbsolutePath string, err error) {
+	isLocal, err := IsLocal(net.ParseIP(srcIP))
 	if err != nil {
 		return 0, "", "", errors.New("failed to determine if address is local: ", err)
 	}
 	if !isLocal {
 		return 0, "", "", ErrNotLocal
 	}
-	if dest.Network != Network_TCP && dest.Network != Network_UDP {
+	if network != "tcp" && network != "udp" {
 		panic("Unsupported network type for process lookup.")
 	}
-	// the core should never has a domain as source(?
-	if dest.Address.Family() == AddressFamilyDomain {
-		panic("Domain addresses are not supported for process lookup.")
-	}
+
 	var procFile string
 
-	switch dest.Network {
-	case Network_TCP:
-		if dest.Address.Family() == AddressFamilyIPv4 {
+	switch network {
+	case "tcp":
+		if net.ParseIP(srcIP).To4() != nil {
 			procFile = "/proc/net/tcp"
-		}
-		if dest.Address.Family() == AddressFamilyIPv6 {
+		} else {
 			procFile = "/proc/net/tcp6"
 		}
-	case Network_UDP:
-		if dest.Address.Family() == AddressFamilyIPv4 {
+	case "udp":
+		if net.ParseIP(srcIP).To4() != nil {
 			procFile = "/proc/net/udp"
-		}
-		if dest.Address.Family() == AddressFamilyIPv6 {
+		} else {
 			procFile = "/proc/net/udp6"
 		}
 	default:
 		panic("Unsupported network type for process lookup.")
 	}
 
-	targetHexAddr, err := formatLittleEndianString(dest.Address, dest.Port)
+	targetHexAddr, err := formatLittleEndianString(net.ParseIP(srcIP), Port(srcPort))
 	if err != nil {
 		return 0, "", "", errors.New("failed to format address: ", err)
 	}
@@ -59,7 +55,7 @@ func FindProcess(dest Destination) (PID int, Name string, AbsolutePath string, e
 		return 0, "", "", errors.New("could not search in ", procFile).Base(err)
 	}
 	if inode == "" {
-		return 0, "", "", errors.New("connection for ", dest.Address, ":", dest.Port, " not found in ", procFile)
+		return 0, "", "", errors.New("connection for ", srcIP, ":", srcPort, " not found in ", procFile)
 	}
 
 	pidStr, err := findPidByInode(inode)
@@ -86,16 +82,16 @@ func FindProcess(dest Destination) (PID int, Name string, AbsolutePath string, e
 	return pid, procName, absPath, nil
 }
 
-func formatLittleEndianString(addr Address, port Port) (string, error) {
-	ip := addr.IP()
+func formatLittleEndianString(addr net.IP, port Port) (string, error) {
+	ip := addr
 	var ipBytes []byte
-	if addr.Family() == AddressFamilyIPv4 {
+	if ip.To4() != nil {
 		ipBytes = ip.To4()
 	} else {
 		ipBytes = ip.To16()
 	}
 	if ipBytes == nil {
-		return "", errors.New("invalid IP format for ", addr.Family(), ": ", ip)
+		return "", errors.New("invalid IP format for ", addr, ": ", ip)
 	}
 
 	for i, j := 0, len(ipBytes)-1; i < j; i, j = i+1, j-1 {

common/net/find_process_others.go

@@ -1,4 +1,4 @@
-//go:build !windows && !linux
+//go:build !windows && !linux && !android
 
 package net
 
@@ -6,6 +6,6 @@ import (
 	"github.com/xtls/xray-core/common/errors"
 )
 
-func FindProcess(dest Destination) (int, string, string, error) {
+func FindProcess(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (int, string, string, error) {
 	return 0, "", "", errors.New("process lookup is not supported on this platform")
 }

common/net/find_process_windows.go

@@ -3,6 +3,7 @@
 package net
 
 import (
+	"net"
 	"net/netip"
 	"path/filepath"
 	"strings"
@@ -49,41 +50,37 @@ func initWin32API() error {
 	return nil
 }
 
-func FindProcess(dest Destination) (PID int, Name string, AbsolutePath string, err error) {
+func FindProcess(network, srcIP string, srcPort uint16, destIP string, destPort uint16) (PID int, Name string, AbsolutePath string, err error) {
 	once.Do(func() {
 		initErr = initWin32API()
 	})
 	if initErr != nil {
 		return 0, "", "", initErr
 	}
-	isLocal, err := IsLocal(dest.Address.IP())
+	isLocal, err := IsLocal(net.ParseIP(srcIP))
 	if err != nil {
 		return 0, "", "", errors.New("failed to determine if address is local: ", err)
 	}
 	if !isLocal {
 		return 0, "", "", ErrNotLocal
 	}
-	if dest.Network != Network_TCP && dest.Network != Network_UDP {
+	if network != "tcp" && network != "udp" {
 		panic("Unsupported network type for process lookup.")
 	}
-	// the core should never has a domain as source(?
-	if dest.Address.Family() == AddressFamilyDomain {
-		panic("Domain addresses are not supported for process lookup.")
-	}
 	var class int
 	var fn uintptr
-	switch dest.Network {
-	case Network_TCP:
+	switch network {
+	case "tcp":
 		fn = getExTCPTable
 		class = tcpTablePidConn
-	case Network_UDP:
+	case "udp":
 		fn = getExUDPTable
 		class = udpTablePid
 	default:
 		panic("Unsupported network type for process lookup.")
 	}
-	ip := dest.Address.IP()
-	port := int(dest.Port)
+	ip := net.ParseIP(srcIP)
+	port := int(srcPort)
 
 	addr, ok := netip.AddrFromSlice(ip)
 	if !ok {
@@ -101,7 +98,15 @@ func FindProcess(dest Destination) (PID int, Name string, AbsolutePath string, e
 		return 0, "", "", err
 	}
 
-	s := newSearcher(dest.Network, dest.Address.Family())
+	networkType := Network_TCP
+	if network == "udp" {
+		networkType = Network_UDP
+	}
+	familyType := AddressFamilyIPv4
+	if addr.Is6() {
+		familyType = AddressFamilyIPv6
+	}
+	s := newSearcher(networkType, familyType)
 
 	pid, err := s.Search(buf, addr, uint16(port))
 	if err != nil {