nebula/udp_linux.go

309 lines
6.9 KiB
Go

package nebula
import (
"encoding/binary"
"encoding/json"
"fmt"
"net"
"strconv"
"strings"
"syscall"
"unsafe"
"golang.org/x/sys/unix"
)
//TODO: make it support reload as best you can!
type udpConn struct {
sysFd int
}
type udpAddr struct {
IP uint32
Port uint16
}
func NewUDPAddr(ip uint32, port uint16) *udpAddr {
return &udpAddr{IP: ip, Port: port}
}
func NewUDPAddrFromString(s string) *udpAddr {
p := strings.Split(s, ":")
if len(p) < 2 {
return nil
}
port, _ := strconv.Atoi(p[1])
return &udpAddr{
IP: ip2int(net.ParseIP(p[0])),
Port: uint16(port),
}
}
type rawSockaddr struct {
Family uint16
Data [14]uint8
}
type rawSockaddrAny struct {
Addr rawSockaddr
Pad [96]int8
}
var x int
func NewListener(ip string, port int, multi bool) (*udpConn, error) {
syscall.ForkLock.RLock()
fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
if err == nil {
syscall.CloseOnExec(fd)
}
syscall.ForkLock.RUnlock()
if err != nil {
syscall.Close(fd)
return nil, fmt.Errorf("unable to open socket: %s", err)
}
var lip [4]byte
copy(lip[:], net.ParseIP(ip).To4())
if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, unix.SO_REUSEPORT, 1); err != nil {
return nil, fmt.Errorf("unable to set SO_REUSEPORT: %s", err)
}
if err = syscall.Bind(fd, &syscall.SockaddrInet4{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
//syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, unix.SO_INCOMING_CPU, x)
//v, err := syscall.GetsockoptInt(fd, syscall.SOL_SOCKET, unix.SO_INCOMING_CPU)
//l.Println(v, err)
return &udpConn{sysFd: fd}, err
}
func (u *udpConn) SetRecvBuffer(n int) error {
return syscall.SetsockoptInt(u.sysFd, syscall.SOL_SOCKET, syscall.SO_RCVBUFFORCE, n)
}
func (u *udpConn) SetSendBuffer(n int) error {
return syscall.SetsockoptInt(u.sysFd, syscall.SOL_SOCKET, syscall.SO_SNDBUFFORCE, n)
}
func (u *udpConn) GetRecvBuffer() (int, error) {
return syscall.GetsockoptInt(int(u.sysFd), syscall.SOL_SOCKET, syscall.SO_RCVBUF)
}
func (u *udpConn) GetSendBuffer() (int, error) {
return syscall.GetsockoptInt(int(u.sysFd), syscall.SOL_SOCKET, syscall.SO_SNDBUF)
}
func (u *udpConn) LocalAddr() (*udpAddr, error) {
var rsa rawSockaddrAny
var rLen = syscall.SizeofSockaddrAny
_, _, err := syscall.Syscall(
syscall.SYS_GETSOCKNAME,
uintptr(u.sysFd),
uintptr(unsafe.Pointer(&rsa)),
uintptr(unsafe.Pointer(&rLen)),
)
if err != 0 {
return nil, err
}
addr := &udpAddr{}
if rsa.Addr.Family == syscall.AF_INET {
addr.Port = uint16(rsa.Addr.Data[0])<<8 + uint16(rsa.Addr.Data[1])
addr.IP = uint32(rsa.Addr.Data[2])<<24 + uint32(rsa.Addr.Data[3])<<16 + uint32(rsa.Addr.Data[4])<<8 + uint32(rsa.Addr.Data[5])
} else {
addr.Port = 0
addr.IP = 0
}
return addr, nil
}
func (u *udpConn) ListenOut(f *Interface) {
plaintext := make([]byte, mtu)
header := &Header{}
fwPacket := &FirewallPacket{}
udpAddr := &udpAddr{}
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(f.udpBatchSize)
for {
n, err := u.ReadMulti(msgs)
if err != nil {
l.WithError(err).Error("Failed to read packets")
continue
}
//metric.Update(int64(n))
for i := 0; i < n; i++ {
udpAddr.IP = binary.BigEndian.Uint32(names[i][4:8])
udpAddr.Port = binary.BigEndian.Uint16(names[i][2:4])
f.readOutsidePackets(udpAddr, plaintext[:0], buffers[i][:msgs[i].Len], header, fwPacket, nb)
}
}
}
func (u *udpConn) Read(addr *udpAddr, b []byte) ([]byte, error) {
var rsa rawSockaddrAny
var rLen = syscall.SizeofSockaddrAny
for {
n, _, err := syscall.Syscall6(
syscall.SYS_RECVFROM,
uintptr(u.sysFd),
uintptr(unsafe.Pointer(&b[0])),
uintptr(len(b)),
uintptr(0),
uintptr(unsafe.Pointer(&rsa)),
uintptr(unsafe.Pointer(&rLen)),
)
if err != 0 {
return nil, &net.OpError{Op: "read", Err: err}
}
if rsa.Addr.Family == syscall.AF_INET {
addr.Port = uint16(rsa.Addr.Data[0])<<8 + uint16(rsa.Addr.Data[1])
addr.IP = uint32(rsa.Addr.Data[2])<<24 + uint32(rsa.Addr.Data[3])<<16 + uint32(rsa.Addr.Data[4])<<8 + uint32(rsa.Addr.Data[5])
} else {
addr.Port = 0
addr.IP = 0
}
return b[:n], nil
}
}
func (u *udpConn) ReadMulti(msgs []rawMessage) (int, error) {
for {
n, _, err := syscall.Syscall6(
syscall.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 *udpConn) WriteTo(b []byte, addr *udpAddr) error {
var rsa syscall.RawSockaddrInet4
//TODO: sometimes addr is nil!
rsa.Family = syscall.AF_INET
p := (*[2]byte)(unsafe.Pointer(&rsa.Port))
p[0] = byte(addr.Port >> 8)
p[1] = byte(addr.Port)
rsa.Addr[0] = byte(addr.IP & 0xff000000 >> 24)
rsa.Addr[1] = byte(addr.IP & 0x00ff0000 >> 16)
rsa.Addr[2] = byte(addr.IP & 0x0000ff00 >> 8)
rsa.Addr[3] = byte(addr.IP & 0x000000ff)
for {
_, _, err := syscall.Syscall6(
syscall.SYS_SENDTO,
uintptr(u.sysFd),
uintptr(unsafe.Pointer(&b[0])),
uintptr(len(b)),
uintptr(0),
uintptr(unsafe.Pointer(&rsa)),
uintptr(syscall.SizeofSockaddrInet4),
)
if err != 0 {
return &net.OpError{Op: "sendto", Err: err}
}
//TODO: handle incomplete writes
return nil
}
}
func (u *udpConn) reloadConfig(c *Config) {
b := c.GetInt("listen.read_buffer", 0)
if b > 0 {
err := u.SetRecvBuffer(b)
if err == nil {
s, err := u.GetRecvBuffer()
if err == nil {
l.WithField("size", s).Info("listen.read_buffer was set")
} else {
l.WithError(err).Warn("Failed to get listen.read_buffer")
}
} else {
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 {
l.WithField("size", s).Info("listen.write_buffer was set")
} else {
l.WithError(err).Warn("Failed to get listen.write_buffer")
}
} else {
l.WithError(err).Error("Failed to set listen.write_buffer")
}
}
}
func (ua *udpAddr) Equals(t *udpAddr) bool {
if t == nil || ua == nil {
return t == nil && ua == nil
}
return ua.IP == t.IP && ua.Port == t.Port
}
func (ua *udpAddr) Copy() *udpAddr {
return &udpAddr{
Port: ua.Port,
IP: ua.IP,
}
}
func (ua *udpAddr) String() string {
return fmt.Sprintf("%s:%v", int2ip(ua.IP), ua.Port)
}
func (ua *udpAddr) MarshalJSON() ([]byte, error) {
return json.Marshal(m{"ip": int2ip(ua.IP), "port": ua.Port})
}
func udp2ip(addr *udpAddr) net.IP {
return int2ip(addr.IP)
}
func udp2ipInt(addr *udpAddr) uint32 {
return addr.IP
}
func hostDidRoam(addr *udpAddr, newaddr *udpAddr) bool {
return !addr.Equals(newaddr)
}