mirror of
https://github.com/slackhq/nebula.git
synced 2026-08-15 14:47:02 +02:00
Nate Brown
344 lines
8.9 KiB
Go
344 lines
8.9 KiB
Go
//go:build !android && !e2e_testing
|
|
// +build !android,!e2e_testing
|
|
|
|
package udp
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"errors"
|
|
"fmt"
|
|
"log/slog"
|
|
"net"
|
|
"net/netip"
|
|
"sync/atomic"
|
|
"syscall"
|
|
"unsafe"
|
|
|
|
"github.com/rcrowley/go-metrics"
|
|
"github.com/slackhq/nebula/config"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
type StdConn struct {
|
|
sysFd int
|
|
closed atomic.Bool
|
|
isV4 bool
|
|
l *slog.Logger
|
|
batch int
|
|
}
|
|
|
|
func NewListener(l *slog.Logger, ip netip.Addr, port int, multi bool, batch int) (Conn, error) {
|
|
af := unix.AF_INET6
|
|
if ip.Is4() {
|
|
af = unix.AF_INET
|
|
}
|
|
syscall.ForkLock.RLock()
|
|
fd, err := unix.Socket(af, unix.SOCK_DGRAM, unix.IPPROTO_UDP)
|
|
if err == nil {
|
|
unix.CloseOnExec(fd)
|
|
}
|
|
syscall.ForkLock.RUnlock()
|
|
if err != nil {
|
|
return nil, fmt.Errorf("unable to open socket: %w", err)
|
|
}
|
|
|
|
if multi {
|
|
if err = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEPORT, 1); err != nil {
|
|
_ = unix.Close(fd)
|
|
return nil, fmt.Errorf("unable to set SO_REUSEPORT: %w", err)
|
|
}
|
|
}
|
|
|
|
var sa unix.Sockaddr
|
|
if ip.Is4() {
|
|
sa4 := &unix.SockaddrInet4{Port: port}
|
|
sa4.Addr = ip.As4()
|
|
sa = sa4
|
|
} else {
|
|
sa6 := &unix.SockaddrInet6{Port: port}
|
|
sa6.Addr = ip.As16()
|
|
sa = sa6
|
|
}
|
|
if err = unix.Bind(fd, sa); err != nil {
|
|
_ = unix.Close(fd)
|
|
return nil, fmt.Errorf("unable to bind to socket: %w", err)
|
|
}
|
|
|
|
return &StdConn{sysFd: fd, isV4: ip.Is4(), l: l, batch: batch}, nil
|
|
}
|
|
|
|
func (u *StdConn) SupportsMultipleReaders() bool {
|
|
return true
|
|
}
|
|
|
|
func (u *StdConn) Rebind() error {
|
|
return nil
|
|
}
|
|
|
|
func (u *StdConn) SetRecvBuffer(n int) error {
|
|
return unix.SetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, n)
|
|
}
|
|
|
|
func (u *StdConn) SetSendBuffer(n int) error {
|
|
return unix.SetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_SNDBUFFORCE, n)
|
|
}
|
|
|
|
func (u *StdConn) SetSoMark(mark int) error {
|
|
return unix.SetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_MARK, mark)
|
|
}
|
|
|
|
func (u *StdConn) GetRecvBuffer() (int, error) {
|
|
return unix.GetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_RCVBUF)
|
|
}
|
|
|
|
func (u *StdConn) GetSendBuffer() (int, error) {
|
|
return unix.GetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_SNDBUF)
|
|
}
|
|
|
|
func (u *StdConn) GetSoMark() (int, error) {
|
|
return unix.GetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_MARK)
|
|
}
|
|
|
|
func (u *StdConn) LocalAddr() (netip.AddrPort, error) {
|
|
sa, err := unix.Getsockname(u.sysFd)
|
|
if err != nil {
|
|
return netip.AddrPort{}, err
|
|
}
|
|
switch sa := sa.(type) {
|
|
case *unix.SockaddrInet4:
|
|
return netip.AddrPortFrom(netip.AddrFrom4(sa.Addr), uint16(sa.Port)), nil
|
|
case *unix.SockaddrInet6:
|
|
return netip.AddrPortFrom(netip.AddrFrom16(sa.Addr), uint16(sa.Port)), nil
|
|
default:
|
|
return netip.AddrPort{}, fmt.Errorf("unsupported sock type: %T", sa)
|
|
}
|
|
}
|
|
|
|
// recvmmsg does one blocking recvmmsg (MSG_WAITFORONE), reading up to len(msgs) datagrams
|
|
func (u *StdConn) recvmmsg(msgs []rawMessage) (int, error) {
|
|
r, _, errno := unix.Syscall6(
|
|
unix.SYS_RECVMMSG,
|
|
uintptr(u.sysFd),
|
|
uintptr(unsafe.Pointer(&msgs[0])),
|
|
uintptr(len(msgs)),
|
|
unix.MSG_WAITFORONE,
|
|
0,
|
|
0,
|
|
)
|
|
if errno != 0 {
|
|
if u.closed.Load() {
|
|
return 0, net.ErrClosed
|
|
}
|
|
return 0, &net.OpError{Op: "recvmmsg", Err: errno}
|
|
}
|
|
n := int(r)
|
|
if (n == 0 || msgs[0].Len == 0) && u.closed.Load() {
|
|
return 0, net.ErrClosed
|
|
}
|
|
return n, nil
|
|
}
|
|
|
|
// recvmsg does one blocking recvmsg into msgs[0]
|
|
func (u *StdConn) recvmsg(msgs []rawMessage) (int, error) {
|
|
r, _, errno := unix.Syscall6(
|
|
unix.SYS_RECVMSG,
|
|
uintptr(u.sysFd),
|
|
uintptr(unsafe.Pointer(&msgs[0].Hdr)),
|
|
0,
|
|
0,
|
|
0,
|
|
0,
|
|
)
|
|
if errno != 0 {
|
|
if u.closed.Load() {
|
|
return 0, net.ErrClosed
|
|
}
|
|
return 0, &net.OpError{Op: "recvmsg", Err: errno}
|
|
}
|
|
if r == 0 && u.closed.Load() {
|
|
return 0, net.ErrClosed
|
|
}
|
|
msgs[0].Len = uint32(r)
|
|
return 1, nil
|
|
}
|
|
|
|
func (u *StdConn) ListenOut(r EncReader) error {
|
|
var ip netip.Addr
|
|
msgs, buffers, names := u.PrepareRawMessages(u.batch)
|
|
read := u.recvmmsg
|
|
if u.batch == 1 {
|
|
read = u.recvmsg
|
|
}
|
|
|
|
for {
|
|
n, err := read(msgs)
|
|
if err != nil {
|
|
if errors.Is(err, unix.EINTR) {
|
|
continue // interrupted by a signal, retry the read
|
|
}
|
|
// net.ErrClosed after Close() is teardown, absorbed by the caller's
|
|
// closed flag like the other platforms; anything else is a real error.
|
|
return err
|
|
}
|
|
|
|
for i := 0; i < n; i++ {
|
|
// Its ok to skip the ok check here, the slicing is the only error that can occur and it will panic
|
|
if u.isV4 {
|
|
ip, _ = netip.AddrFromSlice(names[i][4:8])
|
|
} else {
|
|
ip, _ = netip.AddrFromSlice(names[i][8:24])
|
|
}
|
|
r(netip.AddrPortFrom(ip.Unmap(), binary.BigEndian.Uint16(names[i][2:4])), buffers[i][:msgs[i].Len])
|
|
}
|
|
}
|
|
}
|
|
|
|
func (u *StdConn) WriteTo(b []byte, ip netip.AddrPort) error {
|
|
if u.isV4 {
|
|
return u.writeTo4(b, ip)
|
|
}
|
|
return u.writeTo6(b, ip)
|
|
}
|
|
|
|
func (u *StdConn) writeTo6(b []byte, ip netip.AddrPort) error {
|
|
var rsa unix.RawSockaddrInet6
|
|
rsa.Family = unix.AF_INET6
|
|
rsa.Addr = ip.Addr().As16()
|
|
binary.BigEndian.PutUint16((*[2]byte)(unsafe.Pointer(&rsa.Port))[:], ip.Port())
|
|
|
|
for {
|
|
_, _, err := unix.Syscall6(
|
|
unix.SYS_SENDTO,
|
|
uintptr(u.sysFd),
|
|
uintptr(unsafe.Pointer(&b[0])),
|
|
uintptr(len(b)),
|
|
uintptr(0),
|
|
uintptr(unsafe.Pointer(&rsa)),
|
|
uintptr(unix.SizeofSockaddrInet6),
|
|
)
|
|
if err != 0 {
|
|
return &net.OpError{Op: "sendto", Err: err}
|
|
}
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func (u *StdConn) writeTo4(b []byte, ip netip.AddrPort) error {
|
|
if !ip.Addr().Is4() {
|
|
return ErrInvalidIPv6RemoteForSocket
|
|
}
|
|
|
|
var rsa unix.RawSockaddrInet4
|
|
rsa.Family = unix.AF_INET
|
|
rsa.Addr = ip.Addr().As4()
|
|
binary.BigEndian.PutUint16((*[2]byte)(unsafe.Pointer(&rsa.Port))[:], ip.Port())
|
|
|
|
for {
|
|
_, _, err := unix.Syscall6(
|
|
unix.SYS_SENDTO,
|
|
uintptr(u.sysFd),
|
|
uintptr(unsafe.Pointer(&b[0])),
|
|
uintptr(len(b)),
|
|
uintptr(0),
|
|
uintptr(unsafe.Pointer(&rsa)),
|
|
uintptr(unix.SizeofSockaddrInet4),
|
|
)
|
|
if err != 0 {
|
|
return &net.OpError{Op: "sendto", Err: err}
|
|
}
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func (u *StdConn) ReloadConfig(c *config.C) {
|
|
b := c.GetInt("listen.read_buffer", 0)
|
|
if b > 0 {
|
|
if err := u.SetRecvBuffer(b); err == nil {
|
|
if s, err := u.GetRecvBuffer(); err == nil {
|
|
u.l.Info("listen.read_buffer was set", "size", s)
|
|
} else {
|
|
u.l.Warn("Failed to get listen.read_buffer", "error", err)
|
|
}
|
|
} else {
|
|
u.l.Error("Failed to set listen.read_buffer", "error", err)
|
|
}
|
|
}
|
|
|
|
b = c.GetInt("listen.write_buffer", 0)
|
|
if b > 0 {
|
|
if err := u.SetSendBuffer(b); err == nil {
|
|
if s, err := u.GetSendBuffer(); err == nil {
|
|
u.l.Info("listen.write_buffer was set", "size", s)
|
|
} else {
|
|
u.l.Warn("Failed to get listen.write_buffer", "error", err)
|
|
}
|
|
} else {
|
|
u.l.Error("Failed to set listen.write_buffer", "error", err)
|
|
}
|
|
}
|
|
|
|
b = c.GetInt("listen.so_mark", 0)
|
|
s, err := u.GetSoMark()
|
|
if b > 0 || (err == nil && s != 0) {
|
|
if err := u.SetSoMark(b); err == nil {
|
|
if s, err := u.GetSoMark(); err == nil {
|
|
u.l.Info("listen.so_mark was set", "mark", s)
|
|
} else {
|
|
u.l.Warn("Failed to get listen.so_mark", "error", err)
|
|
}
|
|
} else {
|
|
u.l.Error("Failed to set listen.so_mark", "error", err)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (u *StdConn) getMemInfo(meminfo *[unix.SK_MEMINFO_VARS]uint32) error {
|
|
var vallen uint32 = 4 * unix.SK_MEMINFO_VARS
|
|
_, _, err := unix.Syscall6(unix.SYS_GETSOCKOPT, uintptr(u.sysFd), uintptr(unix.SOL_SOCKET), uintptr(unix.SO_MEMINFO), uintptr(unsafe.Pointer(meminfo)), uintptr(unsafe.Pointer(&vallen)), 0)
|
|
if err != 0 {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (u *StdConn) Close() error {
|
|
u.closed.Store(true)
|
|
// Wake the reader parked in recvmmsg/recvmsg. shutdown(2) on an unconnected socket
|
|
// returns ENOTCONN but still wakes it, so ignore the error.
|
|
// The reader then sees closed and stops touching the fd, making the Close below safe.
|
|
_ = unix.Shutdown(u.sysFd, unix.SHUT_RDWR)
|
|
return unix.Close(u.sysFd)
|
|
}
|
|
|
|
func NewUDPStatsEmitter(udpConns []Conn) func() {
|
|
// Check if our kernel supports SO_MEMINFO before registering the gauges
|
|
var udpGauges [][unix.SK_MEMINFO_VARS]metrics.Gauge
|
|
var meminfo [unix.SK_MEMINFO_VARS]uint32
|
|
if err := udpConns[0].(*StdConn).getMemInfo(&meminfo); err == nil {
|
|
udpGauges = make([][unix.SK_MEMINFO_VARS]metrics.Gauge, len(udpConns))
|
|
for i := range udpConns {
|
|
udpGauges[i] = [unix.SK_MEMINFO_VARS]metrics.Gauge{
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.rmem_alloc", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.rcvbuf", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.wmem_alloc", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.sndbuf", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.fwd_alloc", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.wmem_queued", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.optmem", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.backlog", i), nil),
|
|
metrics.GetOrRegisterGauge(fmt.Sprintf("udp.%d.drops", i), nil),
|
|
}
|
|
}
|
|
}
|
|
|
|
return func() {
|
|
for i, gauges := range udpGauges {
|
|
if err := udpConns[i].(*StdConn).getMemInfo(&meminfo); err == nil {
|
|
for j := 0; j < unix.SK_MEMINFO_VARS; j++ {
|
|
gauges[j].Update(int64(meminfo[j]))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|