Revert "More playing" way too much garbage emitted

This reverts commit fa098c551a23d055f7ba040f14991b21dd72868f.

go.mod

@@ -39,7 +39,6 @@ require (
 )
 
 require (
-	github.com/anacrolix/mmsg v1.1.1 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect

go.sum

@@ -6,8 +6,6 @@ github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuy
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
-github.com/anacrolix/mmsg v1.1.1 h1:4ce/3I5kM7qSF6T5A8MOmDCfac3UqYlk5Bzh5XsWebM=
-github.com/anacrolix/mmsg v1.1.1/go.mod h1:lPCXEN1eDDQtKktdKEzdw+roswx6wWPpeXAl/WpWVDU=
 github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be h1:9AeTilPcZAjCFIImctFaOjnTIavg87rW78vTPkQqLI8=
 github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be/go.mod h1:ySMOLuWl6zY27l47sB3qLNK6tF2fkHG55UZxx8oIVo4=
 github.com/armon/go-radix v1.0.0 h1:F4z6KzEeeQIMeLFa97iZU6vupzoecKdU5TX24SNppXI=

udp/udp_linux.go

@@ -5,6 +5,7 @@ package udp
 
 import (
 	"context"
+	"encoding/binary"
 	"fmt"
 	"net"
 	"net/netip"
@@ -15,13 +16,11 @@ import (
 	"github.com/rcrowley/go-metrics"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
-	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
 )
 
 type StdConn struct {
-	c     *ipv6.PacketConn
-	uc    *net.UDPConn
+	c     *net.UDPConn
 	rc    syscall.RawConn
 	isV4  bool
 	l     *logrus.Logger
@@ -66,7 +65,8 @@ func NewListener(l *logrus.Logger, ip netip.Addr, port int, multi bool, batch in
 		_ = c.Close()
 		return nil, fmt.Errorf("unable to open sysfd: %w", err)
 	}
-	return &StdConn{c: ipv6.NewPacketConn(c), rc: rc, uc: uc, isV4: ip.Is4(), l: l, batch: batch}, err
+
+	return &StdConn{c: uc, rc: rc, isV4: ip.Is4(), l: l, batch: batch}, err
 }
 
 func (u *StdConn) Rebind() error {
@@ -143,48 +143,36 @@ func (u *StdConn) GetSoMark() (int, error) {
 }
 
 func (u *StdConn) LocalAddr() (netip.AddrPort, error) {
-	sa := u.uc.LocalAddr()
+	sa := u.c.LocalAddr()
 	return netip.ParseAddrPort(sa.String())
 }
 
 func (u *StdConn) ListenOut(r EncReader) {
 	var ip netip.Addr
-	var port int
-
-	//u.msgs, u.buffers, u.names = u.PrepareRawMessages(u.batch)
-	//read := u.ReadMulti
-	//if u.batch == 1 {
-	//	read = u.ReadSingle
-	//}
 
-	var err error
-	var n int
-	msgs := make([]ipv6.Message, u.batch)
-	for i := range msgs {
-		msgs[i].Buffers = [][]byte{make([]byte, MTU)}
+	u.msgs, u.buffers, u.names = u.PrepareRawMessages(u.batch)
+	read := u.ReadMulti
+	if u.batch == 1 {
+		read = u.ReadSingle
 	}
 
 	for {
-		//read()
-		n, err = u.c.ReadBatch(msgs, 0)
-		if err != nil {
+		read()
+		if u.err != nil {
 			//TODO: remove logging, return error
-			u.l.WithError(err).Error("udp socket is closed, exiting read loop")
+			u.l.WithError(u.err).Error("udp socket is closed, exiting read loop")
 			return
 		}
 
-		for i := 0; i < n; i++ {
-			switch addr := msgs[i].Addr.(type) {
-			case *net.UDPAddr:
-				// Its ok to skip the ok check here, the slicing is the only error that can occur and it will panic
-				ip, _ = netip.AddrFromSlice(addr.IP)
-				port = addr.Port
-			default:
-				//TODO: this is an error, return?
+		for i := 0; i < int(u.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(u.names[i][4:8])
+			} else {
+				ip, _ = netip.AddrFromSlice(u.names[i][8:24])
 			}
-
 			//u.l.Error("GOT A PACKET", msgs[i].Len)
-			r(netip.AddrPortFrom(ip.Unmap(), uint16(port)), msgs[i].Buffers[0][:msgs[i].N])
+			r(netip.AddrPortFrom(ip.Unmap(), binary.BigEndian.Uint16(u.names[i][2:4])), u.buffers[i][:u.msgs[i].Len])
 		}
 	}
 }
@@ -257,7 +245,7 @@ func (u *StdConn) innerReadMulti(fd uintptr) bool {
 }
 
 func (u *StdConn) WriteTo(b []byte, ip netip.AddrPort) error {
-	_, err := u.uc.WriteToUDPAddrPort(b, ip)
+	_, err := u.c.WriteToUDPAddrPort(b, ip)
 	return err
 }
 
@@ -330,7 +318,7 @@ func (u *StdConn) getMemInfo(meminfo *[unix.SK_MEMINFO_VARS]uint32) error {
 }
 
 func (u *StdConn) Close() error {
-	err := u.uc.Close()
+	err := u.c.Close()
 	return err
 }