mirror of
https://github.com/soypat/lneto.git
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huge tap/bridge overhaul; udp node; dhcp node; DHCP example
This commit is contained in:
soypat
@@ -0,0 +1,189 @@
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package main
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import (
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"crypto/rand"
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"encoding/binary"
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"fmt"
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"net"
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"net/netip"
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"os"
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"time"
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"github.com/soypat/lneto"
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"github.com/soypat/lneto/arp"
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"github.com/soypat/lneto/dhcpv4"
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"github.com/soypat/lneto/ethernet"
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"github.com/soypat/lneto/internal/ltesto"
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"github.com/soypat/lneto/internet"
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"github.com/soypat/lneto/internet/pcap"
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)
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func main() {
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err := run()
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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fmt.Println("success")
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}
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func run() (err error) {
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br := ltesto.NewHTTPTapClient("http://127.0.0.1:7070")
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defer br.Close()
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nicHW := br.HardwareAddr6()
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brHW := nicHW
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brHW[5]++ // We'll be using a similar HW address but with NIC specific identifier modified.
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mtu := br.MTU()
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nicAddr := br.IPPrefix()
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fmt.Println("NIC hardware address:", net.HardwareAddr(nicHW[:]).String(), "bridgeHW:", net.HardwareAddr(brHW[:]).String(), "mtu:", mtu, "addr:", nicAddr.String())
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var stack Stack
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err = stack.Reset(brHW, nicAddr.Addr().Next(), uint16(mtu))
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if err != nil {
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return err
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}
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err = stack.BeginDHCPRequest()
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if err != nil {
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return err
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}
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var shark pcap.PacketBreakdown
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buf := make([]byte, mtu)
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var iframes []pcap.Frame
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lastAction := time.Now()
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for {
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clear(buf)
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nwrite, err := stack.Encapsulate(buf[:], 0)
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if err != nil {
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fmt.Println("ERR:ENCAPSULATE", err)
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} else if nwrite > 0 {
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iframes, err = shark.CaptureEthernet(iframes[:0], buf[:nwrite], 0)
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if err != nil {
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fmt.Println("OU", iframes, err.Error())
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} else {
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fmt.Println("OU", iframes)
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}
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n, err := br.Write(buf[:nwrite])
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if err != nil {
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return err
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} else if n != nwrite {
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return fmt.Errorf("mismatch written bytes %d!=%d", nwrite, n)
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}
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}
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clear(buf)
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nread, err := br.Read(buf)
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if err != nil {
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return err
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} else if nread > 0 {
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iframes, err = shark.CaptureEthernet(iframes[:0], buf[:nread], 0)
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if err != nil {
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fmt.Println("IN", iframes, err.Error())
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} else {
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fmt.Println("IN", iframes)
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}
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err = stack.Demux(buf[:nread], 0)
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if err != nil {
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fmt.Println("ERR:DEMUX", err)
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}
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}
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if nread == 0 && nwrite == 0 && time.Since(lastAction) > 4*time.Second {
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time.Sleep(5 * time.Millisecond)
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} else {
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lastAction = time.Now()
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}
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}
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return nil
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}
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type Stack struct {
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link internet.StackEthernet
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ip internet.StackIP
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arp internet.NodeARP
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udps internet.StackPorts
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dhcp dhcpv4.Client
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}
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func (s *Stack) Demux(b []byte, _ int) error {
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return s.link.Demux(b, 0)
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}
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func (s *Stack) Encapsulate(b []byte, _ int) (int, error) {
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return s.link.Encapsulate(b, 0)
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}
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func (s *Stack) Reset(mac [6]byte, addr netip.Addr, mtu uint16) error {
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err := s.link.Reset6(mac, ethernet.BroadcastAddr(), int(mtu))
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if err != nil {
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return err
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}
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err = s.ip.Reset(addr)
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if err != nil {
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return err
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}
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ipaddr := addr.AsSlice()
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proto := ethernet.TypeIPv4
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if addr.Is6() {
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proto = ethernet.TypeIPv6
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}
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err = s.arp.Reset(arp.HandlerConfig{
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HardwareAddr: mac[:],
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ProtocolAddr: ipaddr,
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MaxQueries: 3,
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MaxPending: 3,
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HardwareType: 1,
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ProtocolType: proto,
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})
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if err != nil {
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return err
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}
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err = s.udps.Reset(uint64(lneto.IPProtoUDP), 2)
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if err != nil {
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return err
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}
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// Now setup stacks.
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err = s.link.Register(&s.arp) // ARP.
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if err != nil {
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return err
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}
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err = s.link.Register(&s.ip) // IPv4 | IPv6
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if err != nil {
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return err
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}
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err = s.ip.Register(&s.udps)
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if err != nil {
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return err
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}
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return nil
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}
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func (s *Stack) BeginDHCPRequest() error {
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addr4 := s.ip.Addr().As4()
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var buf [4]byte
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rand.Read(buf[:])
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xid := binary.LittleEndian.Uint32(buf[:])
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err := s.dhcp.BeginRequest(xid, dhcpv4.RequestConfig{
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RequestedAddr: addr4,
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ClientHardwareAddr: s.link.HardwareAddr6(),
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Hostname: "lneto",
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})
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if err != nil {
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return err
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}
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var u internet.StackUDPPort
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u.SetStackNode(&s.dhcp, dhcpv4.DefaultServerPort)
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err = s.udps.Register(&u)
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if err != nil {
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return err
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}
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return err
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}
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func clear(buf []byte) {
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for i := range buf {
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buf[i] = 0
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}
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}
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+41
-12
@@ -2,6 +2,7 @@ package main
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import (
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"errors"
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"flag"
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"fmt"
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"log"
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"log/slog"
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@@ -9,9 +10,11 @@ import (
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"net/http"
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"net/netip"
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"runtime"
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"strings"
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"time"
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"github.com/soypat/lneto"
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"github.com/soypat/lneto/internal"
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"github.com/soypat/lneto/internal/ltesto"
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"github.com/soypat/lneto/internet/pcap"
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"github.com/soypat/lneto/tcp"
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@@ -27,17 +30,35 @@ func main() {
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}
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func run() error {
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var (
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flagInterface = "tap0"
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)
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flag.StringVar(&flagInterface, "i", flagInterface, "Interface to select. tap* creates a tap interface. Any other name will create a bridge to the name of the interface i.e: 'enp7s0', 'wlp8s0', 'lo'")
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var (
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flagNet = "192.168.10.1/24"
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flagiface = "tap0"
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flagMTU = 1500
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flagPacketQueueSize = 2048
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)
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ip, err := netip.ParsePrefix(flagNet)
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if err != nil {
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return err
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var iface ltesto.Interface
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if strings.HasPrefix(flagInterface, "tap") {
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pfx, err := netip.ParsePrefix(flagNet)
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if err != nil {
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return err
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}
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tap, err := internal.NewTap(flagiface, pfx)
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if err != nil {
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return err
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}
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iface = tap
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} else {
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br, err := internal.NewBridge(flagInterface)
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if err != nil {
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return err
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}
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iface = br
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}
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sv, err := ltesto.NewHTTPTapServer(flagiface, ip, flagMTU, flagPacketQueueSize, flagPacketQueueSize)
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sv, err := ltesto.NewHTTPTapServer(iface, flagPacketQueueSize, flagPacketQueueSize)
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if err != nil {
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return err
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}
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@@ -48,8 +69,12 @@ func run() error {
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frames, err := cap.CaptureEthernet(nil, pkt, 0)
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if err == nil {
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flags, src, dst := getTCPData(frames, pkt)
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if flags != 0 {
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fmt.Println(channel, captime.Format("15:04:05.000"), frames, flags.String(), src, "->", dst)
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if src != 0 {
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if flags != 0 {
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fmt.Println(channel, captime.Format("15:04:05.000"), frames, flags.String(), src, "->", dst)
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} else {
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fmt.Println(channel, captime.Format("15:04:05.000"), frames, src, "->", dst)
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}
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} else {
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fmt.Println(channel, captime.Format("15:04:05.000"), frames)
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}
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@@ -86,12 +111,16 @@ func run() error {
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func getTCPData(frames []pcap.Frame, pkt []byte) (flags tcp.Flags, src, dst uint16) {
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for i := range frames {
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if frames[i].Protocol != lneto.IPProtoTCP {
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continue
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proto := frames[i].Protocol
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if proto == lneto.IPProtoTCP {
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return tcp.Flags(getFrameClassUint(frames[i], pkt, pcap.FieldClassFlags)),
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassSrc)),
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassDst))
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} else if proto == lneto.IPProtoUDP {
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return 0,
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassSrc)),
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassDst))
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}
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return tcp.Flags(getFrameClassUint(frames[i], pkt, pcap.FieldClassFlags)),
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassSrc)),
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uint16(getFrameClassUint(frames[i], pkt, pcap.FieldClassDst))
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}
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return 0, 0, 0
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}
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