supports AF_XDP socket diagnosis; skip XSK diag test if kernel doesn'…

…t support XSK diag

socket.go

@@ -35,3 +35,70 @@ type UnixSocket struct {
 	INode  uint32
 	Cookie [2]uint32
 }
+
+// XDPSocket represents an XDP socket (and the common diagnosis part in
+// particular). Please note that in contrast to [UnixSocket] the XDPSocket type
+// does not feature “State” information.
+type XDPSocket struct {
+	// xdp_diag_msg
+	// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L21
+	Family uint8
+	Type   uint8
+	pad    uint16
+	Ino    uint32
+	Cookie [2]uint32
+}
+
+type XDPInfo struct {
+	// XDP_DIAG_INFO/xdp_diag_info
+	// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L51
+	Ifindex uint32
+	QueueID uint32
+
+	// XDP_DIAG_UID
+	UID uint32
+
+	// XDP_RX_RING
+	// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L56
+	RxRingEntries             uint32
+	TxRingEntries             uint32
+	UmemFillRingEntries       uint32
+	UmemCompletionRingEntries uint32
+
+	// XDR_DIAG_UMEM
+	Umem *XDPDiagUmem
+
+	// XDR_DIAG_STATS
+	Stats *XDPDiagStats
+}
+
+const (
+	XDP_DU_F_ZEROCOPY = 1 << iota
+)
+
+// XDPDiagUmem describes the umem attached to an XDP socket.
+//
+// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L62
+type XDPDiagUmem struct {
+	Size      uint64
+	ID        uint32
+	NumPages  uint32
+	ChunkSize uint32
+	Headroom  uint32
+	Ifindex   uint32
+	QueueID   uint32
+	Flags     uint32
+	Refs      uint32
+}
+
+// XDPDiagStats contains ring statistics for an XDP socket.
+//
+// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L74
+type XDPDiagStats struct {
+	RxDropped     uint64
+	RxInvalid     uint64
+	RxFull        uint64
+	FillRingEmpty uint64
+	TxInvalid     uint64
+	TxRingEmpty   uint64
+}

socket_xdp_linux.go

@@ -0,0 +1,195 @@
+package netlink
+
+import (
+	"errors"
+	"fmt"
+	"syscall"
+
+	"github.com/vishvananda/netlink/nl"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	sizeofXDPSocketRequest = 1 + 1 + 2 + 4 + 4 + 2*4
+	sizeofXDPSocket        = 0x10
+)
+
+// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L12
+type xdpSocketRequest struct {
+	Family   uint8
+	Protocol uint8
+	pad      uint16
+	Ino      uint32
+	Show     uint32
+	Cookie   [2]uint32
+}
+
+func (r *xdpSocketRequest) Serialize() []byte {
+	b := writeBuffer{Bytes: make([]byte, sizeofSocketRequest)}
+	b.Write(r.Family)
+	b.Write(r.Protocol)
+	native.PutUint16(b.Next(2), r.pad)
+	native.PutUint32(b.Next(4), r.Ino)
+	native.PutUint32(b.Next(4), r.Show)
+	native.PutUint32(b.Next(4), r.Cookie[0])
+	native.PutUint32(b.Next(4), r.Cookie[1])
+	return b.Bytes
+}
+
+func (r *xdpSocketRequest) Len() int { return sizeofXDPSocketRequest }
+
+func (s *XDPSocket) deserialize(b []byte) error {
+	if len(b) < sizeofXDPSocket {
+		return fmt.Errorf("XDP socket data short read (%d); want %d", len(b), sizeofXDPSocket)
+	}
+	rb := readBuffer{Bytes: b}
+	s.Family = rb.Read()
+	s.Type = rb.Read()
+	s.pad = native.Uint16(rb.Next(2))
+	s.Ino = native.Uint32(rb.Next(4))
+	s.Cookie[0] = native.Uint32(rb.Next(4))
+	s.Cookie[1] = native.Uint32(rb.Next(4))
+	return nil
+}
+
+// XDPSocketGet returns the XDP socket identified by its inode number and/or
+// socket cookie. Specify the cookie as SOCK_ANY_COOKIE if
+func SocketXDPGetInfo(ino uint32, cookie uint64) (*XDPDiagInfoResp, error) {
+	// We have a problem here: dumping AF_XDP sockets currently does not support
+	// filtering. We thus need to dump all XSKs and then only filter afterwards
+	// :(
+	xsks, err := SocketDiagXDP()
+	if err != nil {
+		return nil, err
+	}
+	checkCookie := cookie != SOCK_ANY_COOKIE && cookie != 0
+	crumblingCookie := [2]uint32{uint32(cookie), uint32(cookie >> 32)}
+	checkIno := ino != 0
+	var xskinfo *XDPDiagInfoResp
+	for _, xsk := range xsks {
+		if checkIno && xsk.XDPDiagMsg.Ino != ino {
+			continue
+		}
+		if checkCookie && xsk.XDPDiagMsg.Cookie != crumblingCookie {
+			continue
+		}
+		if xskinfo != nil {
+			return nil, errors.New("multiple matching XDP sockets")
+		}
+		xskinfo = xsk
+	}
+	if xskinfo == nil {
+		return nil, errors.New("no matching XDP socket")
+	}
+	return xskinfo, nil
+}
+
+// SocketDiagXDP requests XDP_DIAG_INFO for XDP family sockets.
+func SocketDiagXDP() ([]*XDPDiagInfoResp, error) {
+	var result []*XDPDiagInfoResp
+	err := socketDiagXDPExecutor(func(m syscall.NetlinkMessage) error {
+		sockInfo := &XDPSocket{}
+		if err := sockInfo.deserialize(m.Data); err != nil {
+			return err
+		}
+		attrs, err := nl.ParseRouteAttr(m.Data[sizeofXDPSocket:])
+		if err != nil {
+			return err
+		}
+
+		res, err := attrsToXDPDiagInfoResp(attrs, sockInfo)
+		if err != nil {
+			return err
+		}
+
+		result = append(result, res)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// socketDiagXDPExecutor requests XDP_DIAG_INFO for XDP family sockets.
+func socketDiagXDPExecutor(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(&xdpSocketRequest{
+		Family: unix.AF_XDP,
+		Show:   XDP_SHOW_INFO | XDP_SHOW_RING_CFG | XDP_SHOW_UMEM | XDP_SHOW_STATS,
+	})
+	if err := s.Send(req); err != nil {
+		return err
+	}
+
+loop:
+	for {
+		msgs, from, err := s.Receive()
+		if err != nil {
+			return err
+		}
+		if 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")
+		}
+
+		for _, m := range msgs {
+			switch m.Header.Type {
+			case unix.NLMSG_DONE:
+				break loop
+			case unix.NLMSG_ERROR:
+				error := int32(native.Uint32(m.Data[0:4]))
+				return syscall.Errno(-error)
+			}
+			if err := receiver(m); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func attrsToXDPDiagInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *XDPSocket) (*XDPDiagInfoResp, error) {
+	resp := &XDPDiagInfoResp{
+		XDPDiagMsg: sockInfo,
+		XDPInfo:    &XDPInfo{},
+	}
+	for _, a := range attrs {
+		switch a.Attr.Type {
+		case XDP_DIAG_INFO:
+			resp.XDPInfo.Ifindex = native.Uint32(a.Value[0:4])
+			resp.XDPInfo.QueueID = native.Uint32(a.Value[4:8])
+		case XDP_DIAG_UID:
+			resp.XDPInfo.UID = native.Uint32(a.Value[0:4])
+		case XDP_DIAG_RX_RING:
+			resp.XDPInfo.RxRingEntries = native.Uint32(a.Value[0:4])
+		case XDP_DIAG_TX_RING:
+			resp.XDPInfo.TxRingEntries = native.Uint32(a.Value[0:4])
+		case XDP_DIAG_UMEM_FILL_RING:
+			resp.XDPInfo.UmemFillRingEntries = native.Uint32(a.Value[0:4])
+		case XDP_DIAG_UMEM_COMPLETION_RING:
+			resp.XDPInfo.UmemCompletionRingEntries = native.Uint32(a.Value[0:4])
+		case XDP_DIAG_UMEM:
+			umem := &XDPDiagUmem{}
+			if err := umem.deserialize(a.Value); err != nil {
+				return nil, err
+			}
+			resp.XDPInfo.Umem = umem
+		case XDP_DIAG_STATS:
+			stats := &XDPDiagStats{}
+			if err := stats.deserialize(a.Value); err != nil {
+				return nil, err
+			}
+			resp.XDPInfo.Stats = stats
+		}
+	}
+	return resp, nil
+}

socket_xdp_linux_test.go

@@ -0,0 +1,49 @@
+//go:build linux
+// +build linux
+
+package netlink
+
+import (
+	"os"
+	"testing"
+
+	"golang.org/x/sys/unix"
+)
+
+func TestSocketXDPGetInfo(t *testing.T) {
+	xdpsockfd, err := unix.Socket(unix.AF_XDP, unix.SOCK_RAW, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer unix.Close(xdpsockfd)
+
+	wantFamily := unix.AF_XDP
+
+	var xdpsockstat unix.Stat_t
+	err = unix.Fstat(xdpsockfd, &xdpsockstat)
+	if err != nil {
+		t.Fatal(err)
+	}
+	wantIno := xdpsockstat.Ino
+
+	result, err := SocketXDPGetInfo(uint32(wantIno), SOCK_ANY_COOKIE)
+	if err != nil {
+		if os.IsNotExist(err) {
+			t.Skip("kernel lacks support for AF_XDP socket diagnosis")
+		}
+		t.Fatal(err)
+	}
+
+	if got := result.XDPDiagMsg.Family; got != uint8(wantFamily) {
+		t.Fatalf("protocol family = %v, want %v", got, wantFamily)
+	}
+	if got := result.XDPDiagMsg.Ino; got != uint32(wantIno) {
+		t.Fatalf("protocol ino = %v, want %v", got, wantIno)
+	}
+	if result.XDPInfo == nil {
+		t.Fatalf("want non-nil XDPInfo, got nil")
+	}
+	if got := result.XDPInfo.Ifindex; got != 0 {
+		t.Fatalf("ifindex = %v, want 0", got)
+	}
+}

xdp_diag.go

@@ -0,0 +1,34 @@
+package netlink
+
+import "github.com/vishvananda/netlink/nl"
+
+const SOCK_ANY_COOKIE = uint64(nl.TCPDIAG_NOCOOKIE)<<32 + uint64(nl.TCPDIAG_NOCOOKIE)
+
+// XDP diagnosis show flag constants to request particular information elements.
+const (
+	XDP_SHOW_INFO = 1 << iota
+	XDP_SHOW_RING_CFG
+	XDP_SHOW_UMEM
+	XDP_SHOW_MEMINFO
+	XDP_SHOW_STATS
+)
+
+// XDP diag element constants
+const (
+	XDP_DIAG_NONE                 = iota
+	XDP_DIAG_INFO                 // when using XDP_SHOW_INFO
+	XDP_DIAG_UID                  // when using XDP_SHOW_INFO
+	XDP_DIAG_RX_RING              // when using XDP_SHOW_RING_CFG
+	XDP_DIAG_TX_RING              // when using XDP_SHOW_RING_CFG
+	XDP_DIAG_UMEM                 // when using XDP_SHOW_UMEM
+	XDP_DIAG_UMEM_FILL_RING       // when using XDP_SHOW_UMEM
+	XDP_DIAG_UMEM_COMPLETION_RING // when using XDP_SHOW_UMEM
+	XDP_DIAG_MEMINFO              // when using XDP_SHOW_MEMINFO
+	XDP_DIAG_STATS                // when using XDP_SHOW_STATS
+)
+
+// https://elixir.bootlin.com/linux/v6.2/source/include/uapi/linux/xdp_diag.h#L21
+type XDPDiagInfoResp struct {
+	XDPDiagMsg *XDPSocket
+	XDPInfo    *XDPInfo
+}

xdp_linux.go

@@ -0,0 +1,46 @@
+package netlink
+
+import (
+	"bytes"
+	"fmt"
+)
+
+const (
+	xdrDiagUmemLen  = 8 + 8*4
+	xdrDiagStatsLen = 6 * 8
+)
+
+func (x *XDPDiagUmem) deserialize(b []byte) error {
+	if len(b) < xdrDiagUmemLen {
+		return fmt.Errorf("XDP umem diagnosis data short read (%d); want %d", len(b), xdrDiagUmemLen)
+	}
+
+	rb := bytes.NewBuffer(b)
+	x.Size = native.Uint64(rb.Next(8))
+	x.ID = native.Uint32(rb.Next(4))
+	x.NumPages = native.Uint32(rb.Next(4))
+	x.ChunkSize = native.Uint32(rb.Next(4))
+	x.Headroom = native.Uint32(rb.Next(4))
+	x.Ifindex = native.Uint32(rb.Next(4))
+	x.QueueID = native.Uint32(rb.Next(4))
+	x.Flags = native.Uint32(rb.Next(4))
+	x.Refs = native.Uint32(rb.Next(4))
+
+	return nil
+}
+
+func (x *XDPDiagStats) deserialize(b []byte) error {
+	if len(b) < xdrDiagStatsLen {
+		return fmt.Errorf("XDP diagnosis statistics short read (%d); want %d", len(b), xdrDiagStatsLen)
+	}
+
+	rb := bytes.NewBuffer(b)
+	x.RxDropped = native.Uint64(rb.Next(8))
+	x.RxInvalid = native.Uint64(rb.Next(8))
+	x.RxFull = native.Uint64(rb.Next(8))
+	x.FillRingEmpty = native.Uint64(rb.Next(8))
+	x.TxInvalid = native.Uint64(rb.Next(8))
+	x.TxRingEmpty = native.Uint64(rb.Next(8))
+
+	return nil
+}