Implement UDP socket diagnostics

Signed-off-by: Sven Rebhan <srebhan@influxdata.com>

inet_diag.go

@@ -29,3 +29,8 @@ type InetDiagTCPInfoResp struct {
 	TCPInfo     *TCPInfo
 	TCPBBRInfo  *TCPBBRInfo
 }
+
+type InetDiagUDPInfoResp struct {
+	InetDiagMsg *Socket
+	Memory      *MemInfo
+}

socket_linux.go

@@ -174,8 +174,18 @@ func SocketGet(local, remote net.Addr) (*Socket, error) {
 
 // SocketDiagTCPInfo requests INET_DIAG_INFO for TCP protocol for specified family type and return with extension TCP info.
 func SocketDiagTCPInfo(family uint8) ([]*InetDiagTCPInfoResp, error) {
+	// Construct the request
+	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
+	req.AddData(&socketRequest{
+		Family:   family,
+		Protocol: unix.IPPROTO_TCP,
+		Ext:      (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
+		States:   uint32(0xfff), // all states
+	})
+
+	// Do the query and parse the result
 	var result []*InetDiagTCPInfoResp
-	err := socketDiagTCPExecutor(family, func(m syscall.NetlinkMessage) error {
+	err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
 		sockInfo := &Socket{}
 		if err := sockInfo.deserialize(m.Data); err != nil {
 			return err
@@ -201,8 +211,18 @@ func SocketDiagTCPInfo(family uint8) ([]*InetDiagTCPInfoResp, error) {
 
 // SocketDiagTCP requests INET_DIAG_INFO for TCP protocol for specified family type and return related socket.
 func SocketDiagTCP(family uint8) ([]*Socket, error) {
+	// Construct the request
+	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
+	req.AddData(&socketRequest{
+		Family:   family,
+		Protocol: unix.IPPROTO_TCP,
+		Ext:      (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
+		States:   uint32(0xfff), // all states
+	})
+
+	// Do the query and parse the result
 	var result []*Socket
-	err := socketDiagTCPExecutor(family, func(m syscall.NetlinkMessage) error {
+	err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
 		sockInfo := &Socket{}
 		if err := sockInfo.deserialize(m.Data); err != nil {
 			return err
@@ -216,21 +236,82 @@ func SocketDiagTCP(family uint8) ([]*Socket, error) {
 	return result, nil
 }
 
-// socketDiagTCPExecutor requests INET_DIAG_INFO for TCP protocol for specified family type.
+// SocketDiagUDPInfo requests INET_DIAG_INFO for UDP protocol for specified family type and return with extension info.
-func socketDiagTCPExecutor(family uint8, receiver func(syscall.NetlinkMessage) error) error {
+func SocketDiagUDPInfo(family uint8) ([]*InetDiagUDPInfoResp, error) {
+	// Construct the request
+	var extensions uint8
+	extensions = 1 << (INET_DIAG_VEGASINFO - 1)
+	extensions |= 1 << (INET_DIAG_INFO - 1)
+	extensions |= 1 << (INET_DIAG_MEMINFO - 1)
+
+	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
+	req.AddData(&socketRequest{
+		Family:   family,
+		Protocol: unix.IPPROTO_UDP,
+		Ext:      extensions,
+		States:   uint32(0xfff), // all states
+	})
+
+	// Do the query and parse the result
+	var result []*InetDiagUDPInfoResp
+	err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
+		sockInfo := &Socket{}
+		if err := sockInfo.deserialize(m.Data); err != nil {
+			return err
+		}
+		attrs, err := nl.ParseRouteAttr(m.Data[sizeofSocket:])
+		if err != nil {
+			return err
+		}
+
+		res, err := attrsToInetDiagUDPInfoResp(attrs, sockInfo)
+		if err != nil {
+			return err
+		}
+
+		result = append(result, res)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// SocketDiagUDP requests INET_DIAG_INFO for UDP protocol for specified family type and return related socket.
+func SocketDiagUDP(family uint8) ([]*Socket, error) {
+	// Construct the request
+	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
+	req.AddData(&socketRequest{
+		Family:   family,
+		Protocol: unix.IPPROTO_UDP,
+		Ext:      (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
+		States:   uint32(0xfff), // all states
+	})
+
+	// Do the query and parse the result
+	var result []*Socket
+	err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
+		sockInfo := &Socket{}
+		if err := sockInfo.deserialize(m.Data); err != nil {
+			return err
+		}
+		result = append(result, sockInfo)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// socketDiagExecutor requests diagnoses info from the NETLINK_INET_DIAG socket for the specified request.
+func socketDiagExecutor(req *nl.NetlinkRequest, receiver func(syscall.NetlinkMessage) error) error {
 	s, err := nl.Subscribe(unix.NETLINK_INET_DIAG)
 	if err != nil {
 		return err
 	}
 	defer s.Close()
-
-	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
-	req.AddData(&socketRequest{
-		Family:   family,
-		Protocol: unix.IPPROTO_TCP,
-		Ext:      (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
-		States:   uint32(0xfff), // All TCP states
-	})
 	s.Send(req)
 
 loop:
@@ -240,7 +321,7 @@ loop:
 			return err
 		}
 		if from.Pid != nl.PidKernel {
-			return fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
+			return fmt.Errorf("wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
 		}
 		if len(msgs) == 0 {
 			return errors.New("no message nor error from netlink")
@@ -263,29 +344,40 @@ loop:
 }
 
 func attrsToInetDiagTCPInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *Socket) (*InetDiagTCPInfoResp, error) {
-	var tcpInfo *TCPInfo
+	info := &InetDiagTCPInfoResp{
-	var tcpBBRInfo *TCPBBRInfo
+		InetDiagMsg: sockInfo,
+	}
 	for _, a := range attrs {
-		if a.Attr.Type == INET_DIAG_INFO {
+		switch a.Attr.Type {
-			tcpInfo = &TCPInfo{}
+		case INET_DIAG_INFO:
-			if err := tcpInfo.deserialize(a.Value); err != nil {
+			info.TCPInfo = &TCPInfo{}
+			if err := info.TCPInfo.deserialize(a.Value); err != nil {
 				return nil, err
 			}
-			continue
+		case INET_DIAG_BBRINFO:
-		}
+			info.TCPBBRInfo = &TCPBBRInfo{}
-
+			if err := info.TCPBBRInfo.deserialize(a.Value); err != nil {
-		if a.Attr.Type == INET_DIAG_BBRINFO {
-			tcpBBRInfo = &TCPBBRInfo{}
-			if err := tcpBBRInfo.deserialize(a.Value); err != nil {
 				return nil, err
 			}
-			continue
 		}
 	}
 
-	return &InetDiagTCPInfoResp{
+	return info, nil
-		InetDiagMsg: sockInfo,
+}
-		TCPInfo:     tcpInfo,
+
-		TCPBBRInfo:  tcpBBRInfo,
+func attrsToInetDiagUDPInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *Socket) (*InetDiagUDPInfoResp, error) {
-	}, nil
+	info := &InetDiagUDPInfoResp{
+		InetDiagMsg: sockInfo,
+	}
+	for _, a := range attrs {
+		switch a.Attr.Type {
+		case INET_DIAG_MEMINFO:
+			info.Memory = &MemInfo{}
+			if err := info.Memory.deserialize(a.Value); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return info, nil
 }

socket_test.go

@@ -1,3 +1,4 @@
+//go:build linux
 // +build linux
 
 package netlink
@@ -75,3 +76,18 @@ func TestSocketDiagTCPInfo(t *testing.T) {
 		}
 	}
 }
+
+func TestSocketDiagUDPnfo(t *testing.T) {
+	for _, want := range []uint8{syscall.AF_INET, syscall.AF_INET6} {
+		result, err := SocketDiagUDPInfo(want)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for _, r := range result {
+			if got := r.InetDiagMsg.Family; got != want {
+				t.Fatalf("protocol family = %v, want %v", got, want)
+			}
+		}
+	}
+}

tcp.go

@@ -82,3 +82,11 @@ type TCPBBRInfo struct {
 	BBRPacingGain uint32
 	BBRCwndGain   uint32
 }
+
+// According to https://man7.org/linux/man-pages/man7/sock_diag.7.html
+type MemInfo struct {
+	RMem uint32
+	WMem uint32
+	FMem uint32
+	TMem uint32
+}

tcp_linux.go

@@ -8,6 +8,7 @@ import (
 
 const (
 	tcpBBRInfoLen = 20
+	memInfoLen    = 16
 )
 
 func checkDeserErr(err error) error {
@@ -351,3 +352,17 @@ func (t *TCPBBRInfo) deserialize(b []byte) error {
 
 	return nil
 }
+
+func (m *MemInfo) deserialize(b []byte) error {
+	if len(b) != memInfoLen {
+		return errors.New("Invalid length")
+	}
+
+	rb := bytes.NewBuffer(b)
+	m.RMem = native.Uint32(rb.Next(4))
+	m.WMem = native.Uint32(rb.Next(4))
+	m.FMem = native.Uint32(rb.Next(4))
+	m.TMem = native.Uint32(rb.Next(4))
+
+	return nil
+}