Chore: move find process name to a single part

component/process/process_freebsd_amd64.go

@@ -0,0 +1,228 @@
+package process
+
+import (
+	"encoding/binary"
+	"fmt"
+	"net"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/log"
+)
+
+// store process name for when dealing with multiple PROCESS-NAME rules
+var (
+	defaultSearcher *searcher
+
+	once sync.Once
+)
+
+func findProcessName(network string, ip net.IP, srcPort int) (string, error) {
+	once.Do(func() {
+		if err := initSearcher(); err != nil {
+			log.Errorln("Initialize PROCESS-NAME failed: %s", err.Error())
+			log.Warnln("All PROCESS-NAME rules will be skipped")
+			return
+		}
+	})
+
+	var spath string
+	isTCP := network == TCP
+	switch network {
+	case TCP:
+		spath = "net.inet.tcp.pcblist"
+	case UDP:
+		spath = "net.inet.udp.pcblist"
+	default:
+		return "", ErrInvalidNetwork
+	}
+
+	value, err := syscall.Sysctl(spath)
+	if err != nil {
+		return "", err
+	}
+
+	buf := []byte(value)
+	pid, err := defaultSearcher.Search(buf, ip, uint16(srcPort), isTCP)
+	if err != nil {
+		return "", err
+	}
+
+	return getExecPathFromPID(pid)
+}
+
+func getExecPathFromPID(pid uint32) (string, error) {
+	buf := make([]byte, 2048)
+	size := uint64(len(buf))
+	// CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, pid
+	mib := [4]uint32{1, 14, 12, pid}
+
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS___SYSCTL,
+		uintptr(unsafe.Pointer(&mib[0])),
+		uintptr(len(mib)),
+		uintptr(unsafe.Pointer(&buf[0])),
+		uintptr(unsafe.Pointer(&size)),
+		0,
+		0)
+	if errno != 0 || size == 0 {
+		return "", errno
+	}
+
+	return filepath.Base(string(buf[:size-1])), nil
+}
+
+func readNativeUint32(b []byte) uint32 {
+	return *(*uint32)(unsafe.Pointer(&b[0]))
+}
+
+type searcher struct {
+	// sizeof(struct xinpgen)
+	headSize int
+	// sizeof(struct xtcpcb)
+	tcpItemSize int
+	// sizeof(struct xinpcb)
+	udpItemSize  int
+	udpInpOffset int
+	port         int
+	ip           int
+	vflag        int
+	socket       int
+
+	// sizeof(struct xfile)
+	fileItemSize int
+	data         int
+	pid          int
+}
+
+func (s *searcher) Search(buf []byte, ip net.IP, port uint16, isTCP bool) (uint32, error) {
+	var itemSize int
+	var inpOffset int
+
+	if isTCP {
+		// struct xtcpcb
+		itemSize = s.tcpItemSize
+		inpOffset = 8
+	} else {
+		// struct xinpcb
+		itemSize = s.udpItemSize
+		inpOffset = s.udpInpOffset
+	}
+
+	isIPv4 := ip.To4() != nil
+	// skip the first xinpgen block
+	for i := s.headSize; i+itemSize <= len(buf); i += itemSize {
+		inp := i + inpOffset
+
+		srcPort := binary.BigEndian.Uint16(buf[inp+s.port : inp+s.port+2])
+
+		if port != srcPort {
+			continue
+		}
+
+		// xinpcb.inp_vflag
+		flag := buf[inp+s.vflag]
+
+		var srcIP net.IP
+		switch {
+		case flag&0x1 > 0 && isIPv4:
+			// ipv4
+			srcIP = net.IP(buf[inp+s.ip : inp+s.ip+4])
+		case flag&0x2 > 0 && !isIPv4:
+			// ipv6
+			srcIP = net.IP(buf[inp+s.ip-12 : inp+s.ip+4])
+		default:
+			continue
+		}
+
+		if !ip.Equal(srcIP) {
+			continue
+		}
+
+		// xsocket.xso_so, interpreted as big endian anyway since it's only used for comparison
+		socket := binary.BigEndian.Uint64(buf[inp+s.socket : inp+s.socket+8])
+		return s.searchSocketPid(socket)
+	}
+	return 0, ErrNotFound
+}
+
+func (s *searcher) searchSocketPid(socket uint64) (uint32, error) {
+	value, err := syscall.Sysctl("kern.file")
+	if err != nil {
+		return 0, err
+	}
+
+	buf := []byte(value)
+
+	// struct xfile
+	itemSize := s.fileItemSize
+	for i := 0; i+itemSize <= len(buf); i += itemSize {
+		// xfile.xf_data
+		data := binary.BigEndian.Uint64(buf[i+s.data : i+s.data+8])
+		if data == socket {
+			// xfile.xf_pid
+			pid := readNativeUint32(buf[i+s.pid : i+s.pid+4])
+			return pid, nil
+		}
+	}
+	return 0, ErrNotFound
+}
+
+func newSearcher(major int) *searcher {
+	var s *searcher = nil
+	switch major {
+	case 11:
+		s = &searcher{
+			headSize:     32,
+			tcpItemSize:  1304,
+			udpItemSize:  632,
+			port:         198,
+			ip:           228,
+			vflag:        116,
+			socket:       88,
+			fileItemSize: 80,
+			data:         56,
+			pid:          8,
+			udpInpOffset: 8,
+		}
+	case 12:
+		s = &searcher{
+			headSize:     64,
+			tcpItemSize:  744,
+			udpItemSize:  400,
+			port:         254,
+			ip:           284,
+			vflag:        392,
+			socket:       16,
+			fileItemSize: 128,
+			data:         56,
+			pid:          8,
+		}
+	}
+	return s
+}
+
+func initSearcher() error {
+	osRelease, err := syscall.Sysctl("kern.osrelease")
+	if err != nil {
+		return err
+	}
+
+	dot := strings.Index(osRelease, ".")
+	if dot != -1 {
+		osRelease = osRelease[:dot]
+	}
+	major, err := strconv.Atoi(osRelease)
+	if err != nil {
+		return err
+	}
+	defaultSearcher = newSearcher(major)
+	if defaultSearcher == nil {
+		return fmt.Errorf("unsupported freebsd version %d", major)
+	}
+	return nil
+}