nebula/udp/udp_linux.go

296 lines
7.2 KiB
Go

//go:build !android && !e2e_testing
// +build !android,!e2e_testing
package udp
import (
"encoding/binary"
"fmt"
"net"
"syscall"
"unsafe"
"github.com/rcrowley/go-metrics"
"github.com/sirupsen/logrus"
"github.com/slackhq/nebula/config"
"github.com/slackhq/nebula/firewall"
"github.com/slackhq/nebula/header"
"golang.org/x/sys/unix"
)
//TODO: make it support reload as best you can!
type Conn struct {
sysFd int
l *logrus.Logger
batch int
}
var x int
// From linux/sock_diag.h
const (
_SK_MEMINFO_RMEM_ALLOC = iota
_SK_MEMINFO_RCVBUF
_SK_MEMINFO_WMEM_ALLOC
_SK_MEMINFO_SNDBUF
_SK_MEMINFO_FWD_ALLOC
_SK_MEMINFO_WMEM_QUEUED
_SK_MEMINFO_OPTMEM
_SK_MEMINFO_BACKLOG
_SK_MEMINFO_DROPS
_SK_MEMINFO_VARS
)
type _SK_MEMINFO [_SK_MEMINFO_VARS]uint32
func NewListener(l *logrus.Logger, ip net.IP, port int, multi bool, batch int) (*Conn, error) {
syscall.ForkLock.RLock()
fd, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_UDP)
if err == nil {
unix.CloseOnExec(fd)
}
syscall.ForkLock.RUnlock()
if err != nil {
unix.Close(fd)
return nil, fmt.Errorf("unable to open socket: %s", err)
}
var lip [16]byte
copy(lip[:], ip.To16())
if multi {
if err = unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_REUSEPORT, 1); err != nil {
return nil, fmt.Errorf("unable to set SO_REUSEPORT: %s", err)
}
}
//TODO: support multiple listening IPs (for limiting ipv6)
if err = unix.Bind(fd, &unix.SockaddrInet6{Addr: lip, Port: port}); err != nil {
return nil, fmt.Errorf("unable to bind to socket: %s", err)
}
//TODO: this may be useful for forcing threads into specific cores
//unix.SetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_INCOMING_CPU, x)
//v, err := unix.GetsockoptInt(fd, unix.SOL_SOCKET, unix.SO_INCOMING_CPU)
//l.Println(v, err)
return &Conn{sysFd: fd, l: l, batch: batch}, err
}
func (u *Conn) Rebind() error {
return nil
}
func (u *Conn) SetRecvBuffer(n int) error {
return unix.SetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, n)
}
func (u *Conn) SetSendBuffer(n int) error {
return unix.SetsockoptInt(u.sysFd, unix.SOL_SOCKET, unix.SO_SNDBUFFORCE, n)
}
func (u *Conn) GetRecvBuffer() (int, error) {
return unix.GetsockoptInt(int(u.sysFd), unix.SOL_SOCKET, unix.SO_RCVBUF)
}
func (u *Conn) GetSendBuffer() (int, error) {
return unix.GetsockoptInt(int(u.sysFd), unix.SOL_SOCKET, unix.SO_SNDBUF)
}
func (u *Conn) LocalAddr() (*Addr, error) {
sa, err := unix.Getsockname(u.sysFd)
if err != nil {
return nil, err
}
addr := &Addr{}
switch sa := sa.(type) {
case *unix.SockaddrInet4:
addr.IP = net.IP{sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3]}.To16()
addr.Port = uint16(sa.Port)
case *unix.SockaddrInet6:
addr.IP = sa.Addr[0:]
addr.Port = uint16(sa.Port)
}
return addr, nil
}
func (u *Conn) ListenOut(r EncReader, lhf LightHouseHandlerFunc, cache *firewall.ConntrackCacheTicker, q int) {
plaintext := make([]byte, MTU)
h := &header.H{}
fwPacket := &firewall.Packet{}
udpAddr := &Addr{}
nb := make([]byte, 12, 12)
//TODO: should we track this?
//metric := metrics.GetOrRegisterHistogram("test.batch_read", nil, metrics.NewExpDecaySample(1028, 0.015))
msgs, buffers, names := u.PrepareRawMessages(u.batch)
read := u.ReadMulti
if u.batch == 1 {
read = u.ReadSingle
}
for {
n, err := read(msgs)
if err != nil {
u.l.WithError(err).Error("Failed to read packets")
continue
}
//metric.Update(int64(n))
for i := 0; i < n; i++ {
udpAddr.IP = names[i][8:24]
udpAddr.Port = binary.BigEndian.Uint16(names[i][2:4])
r(udpAddr, plaintext[:0], buffers[i][:msgs[i].Len], h, fwPacket, lhf, nb, q, cache.Get(u.l))
}
}
}
func (u *Conn) ReadSingle(msgs []rawMessage) (int, error) {
for {
n, _, err := unix.Syscall6(
unix.SYS_RECVMSG,
uintptr(u.sysFd),
uintptr(unsafe.Pointer(&(msgs[0].Hdr))),
0,
0,
0,
0,
)
if err != 0 {
return 0, &net.OpError{Op: "recvmsg", Err: err}
}
msgs[0].Len = uint32(n)
return 1, nil
}
}
func (u *Conn) ReadMulti(msgs []rawMessage) (int, error) {
for {
n, _, err := unix.Syscall6(
unix.SYS_RECVMMSG,
uintptr(u.sysFd),
uintptr(unsafe.Pointer(&msgs[0])),
uintptr(len(msgs)),
unix.MSG_WAITFORONE,
0,
0,
)
if err != 0 {
return 0, &net.OpError{Op: "recvmmsg", Err: err}
}
return int(n), nil
}
}
func (u *Conn) WriteTo(b []byte, addr *Addr) error {
var rsa unix.RawSockaddrInet6
rsa.Family = unix.AF_INET6
p := (*[2]byte)(unsafe.Pointer(&rsa.Port))
p[0] = byte(addr.Port >> 8)
p[1] = byte(addr.Port)
copy(rsa.Addr[:], addr.IP)
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}
}
//TODO: handle incomplete writes
return nil
}
}
func (u *Conn) ReloadConfig(c *config.C) {
b := c.GetInt("listen.read_buffer", 0)
if b > 0 {
err := u.SetRecvBuffer(b)
if err == nil {
s, err := u.GetRecvBuffer()
if err == nil {
u.l.WithField("size", s).Info("listen.read_buffer was set")
} else {
u.l.WithError(err).Warn("Failed to get listen.read_buffer")
}
} else {
u.l.WithError(err).Error("Failed to set listen.read_buffer")
}
}
b = c.GetInt("listen.write_buffer", 0)
if b > 0 {
err := u.SetSendBuffer(b)
if err == nil {
s, err := u.GetSendBuffer()
if err == nil {
u.l.WithField("size", s).Info("listen.write_buffer was set")
} else {
u.l.WithError(err).Warn("Failed to get listen.write_buffer")
}
} else {
u.l.WithError(err).Error("Failed to set listen.write_buffer")
}
}
}
func (u *Conn) getMemInfo(meminfo *_SK_MEMINFO) error {
var vallen uint32 = 4 * _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 NewUDPStatsEmitter(udpConns []*Conn) func() {
// Check if our kernel supports SO_MEMINFO before registering the gauges
var udpGauges [][_SK_MEMINFO_VARS]metrics.Gauge
var meminfo _SK_MEMINFO
if err := udpConns[0].getMemInfo(&meminfo); err == nil {
udpGauges = make([][_SK_MEMINFO_VARS]metrics.Gauge, len(udpConns))
for i := range udpConns {
udpGauges[i] = [_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].getMemInfo(&meminfo); err == nil {
for j := 0; j < _SK_MEMINFO_VARS; j++ {
gauges[j].Update(int64(meminfo[j]))
}
}
}
}
}