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supports AF_XDP socket diagnosis; skip XSK diag test if kernel doesn't support XSK diag

This commit is contained in:
TheDiveO 2024-07-05 19:04:27 +02:00 committed by Alessandro Boch
parent aed23dbf5e
commit d13535d71e
5 changed files with 391 additions and 0 deletions
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67
socket.go
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@ -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
}

195
socket_xdp_linux.go Normal file
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@ -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
}

49
socket_xdp_linux_test.go Normal file
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@ -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)
}
}

34
xdp_diag.go Normal file
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@ -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
}

46
xdp_linux.go Normal file
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@ -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
}