mosers
/
eaas-vde-proxy
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Added missing error handling

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main
Simon Moser vor 3 Jahren
Ursprung 240e4fd34e
Commit 03f1221dc8
Signiert von: mosers
GPG-Schlüssel-ID: 96B3365A234B500C
2 geänderte Dateien mit 56 neuen und 50 gelöschten Zeilen
Statistiken anzeigen Patch-Datei herunterladen Vergleichs-Datei herunterladen

2
.gitignore vendored
Unescapen Escapen Datei anzeigen

@ -3,3 +3,5 @@
*.qcow2
test-env/images
proxy/proxy
proxy/.idea
.idea

96
proxy/main.go
Unescapen Escapen Datei anzeigen

@ -7,7 +7,7 @@ import (
"fmt"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
dhcp "github.com/krolaw/dhcp4"
"github.com/krolaw/dhcp4"
log "github.com/sirupsen/logrus"
"io"
"net"
@ -51,7 +51,7 @@ func main() {
DisableTimestamp: true,
})
if *logFile != "" {
if f, err := os.OpenFile(*logFile, os.O_WRONLY | os.O_CREATE, 0755); err != nil {
if f, err := os.OpenFile(*logFile, os.O_WRONLY|os.O_CREATE, 0755); err != nil {
log.Error("Error opening logFile ", *logFile)
} else {
log.SetOutput(f)
@ -156,8 +156,12 @@ func pipeForward(prefix string) {
// Forward original frame to other plug
if Passthrough {
writer.Write(frameLength)
writer.Write(frameBytes)
if _, err := writer.Write(frameLength); err != nil {
log.Error("Error forwarding original packet length", err)
}
if _, err := writer.Write(frameBytes); err != nil {
log.Error("Error forwarding original packet data", err)
}
continue
}
@ -180,8 +184,12 @@ func pipeForward(prefix string) {
}
// Forward modified frame to other plug
writer.Write(newFrameLength)
writer.Write(newFrameBytes)
if _, err := writer.Write(newFrameLength); err != nil {
log.Error("Error forwarding packet length", err)
}
if _, err := writer.Write(newFrameBytes); err != nil {
log.Error("Error forwarding packet data", err)
}
}
}
@ -211,7 +219,7 @@ func filterIP(prefix string, dst interface{}, src interface{}, context gopacket.
return
} else if prefix == cmd.Out {
if isIp {
if!ip.IsGlobalUnicast() {
if !ip.IsGlobalUnicast() {
return
}
OldIP = *ip
@ -274,19 +282,19 @@ func filterMAC(prefix string, dst interface{}, src interface{}, context gopacket
}
func handleDHCP(content []byte, srcMAC net.HardwareAddr, prefix string) {
req := dhcp.Packet(content)
req := dhcp4.Packet(content)
if req.HLen() > 16 { // Invalid size
log.Error(prefix, "Invalid DHCP size")
return
}
options := req.ParseOptions()
var reqType dhcp.MessageType
if t := options[dhcp.OptionDHCPMessageType]; len(t) != 1 {
var reqType dhcp4.MessageType
if t := options[dhcp4.OptionDHCPMessageType]; len(t) != 1 {
log.Error(prefix, "Invalid DHCP message type")
return
} else {
reqType = dhcp.MessageType(t[0])
if reqType < dhcp.Discover || reqType > dhcp.Inform {
reqType = dhcp4.MessageType(t[0])
if reqType < dhcp4.Discover || reqType > dhcp4.Inform {
log.Error(prefix, "Invalid DHCP message type: ", reqType)
return
}
@ -294,13 +302,13 @@ func handleDHCP(content []byte, srcMAC net.HardwareAddr, prefix string) {
log.Debug(prefix, "DHCP message registered: ", reqType)
if prefix == cmd.Out {
switch reqType {
case dhcp.Discover:
case dhcp4.Discover:
if OldIP == nil {
log.Fatal(prefix, "DHCPDISCOVER but not previous address is known")
}
sendDHCPReply(req, dhcp.Offer, OldIP, options, srcMAC)
case dhcp.Request:
reqIP := net.IP(options[dhcp.OptionRequestedIPAddress])
sendDHCPReply(req, dhcp4.Offer, OldIP, options, srcMAC)
case dhcp4.Request:
reqIP := net.IP(options[dhcp4.OptionRequestedIPAddress])
if reqIP == nil {
reqIP = req.CIAddr()
}
@ -308,34 +316,37 @@ func handleDHCP(content []byte, srcMAC net.HardwareAddr, prefix string) {
log.Error(prefix, "Invalid IP requested in DHCP: ", reqIP)
return
}
sendDHCPReply(req, dhcp.ACK, reqIP, options, srcMAC)
sendDHCPReply(req, dhcp4.ACK, reqIP, options, srcMAC)
default:
return
}
} else {
// TODO: talk to dhcp server
// TODO: talk to DHCP server
}
}
// sendDHCPReply creates a response dhcp packet and sends it
func sendDHCPReply(req dhcp.Packet, mt dhcp.MessageType, lease net.IP, reqOpt dhcp.Options, dstMAC net.HardwareAddr) {
// sendDHCPReply creates a response DHCP packet and sends it
func sendDHCPReply(req dhcp4.Packet, mt dhcp4.MessageType, lease net.IP, reqOpt dhcp4.Options, dstMAC net.HardwareAddr) {
log.Info("Sending DHCP response: ", mt, lease)
// Getting the options
serverIP := []byte{10, 0, 0, 1} // TODO: serverIP
serverMAC := util.GenerateMac("") // TODO: server MAC
opt := dhcp.Options{
dhcp.OptionSubnetMask: []byte{255, 255, 255, 0}, // TODO: subnet mask
dhcp.OptionRouter: serverIP, // TODO: Presuming Server is also your router
dhcp.OptionDomainNameServer: serverIP, // TODO: Presuming Server is also your DNS server
}.SelectOrderOrAll(reqOpt[dhcp.OptionParameterRequestList])
opt := dhcp4.Options{
dhcp4.OptionSubnetMask: []byte{255, 255, 255, 0}, // TODO: subnet mask
dhcp4.OptionRouter: serverIP, // TODO: Presuming Server is also your router
dhcp4.OptionDomainNameServer: serverIP, // TODO: Presuming Server is also your DNS server
}.SelectOrderOrAll(reqOpt[dhcp4.OptionParameterRequestList])
// Creating the full packet layer by layer
dhcplayer := dhcp.ReplyPacket(req, mt, serverIP, lease, 24 * time.Hour, opt)
buf := gopacket.NewSerializeBuffer()
opts := gopacket.SerializeOptions{
ComputeChecksums: true,
FixLengths: true,
}
eth := layers.Ethernet{
SrcMAC: serverMAC,
DstMAC: dstMAC,
EthernetType: layers.EthernetTypeIPv4,
}
ipv4 := layers.IPv4{
Version: 4,
@ -348,18 +359,12 @@ func sendDHCPReply(req dhcp.Packet, mt dhcp.MessageType, lease net.IP, reqOpt dh
SrcPort: 67,
DstPort: 68,
}
udp.SetNetworkLayerForChecksum(&ipv4)
err := gopacket.SerializeLayers(buf, opts,
&layers.Ethernet{
SrcMAC: serverMAC,
DstMAC: dstMAC,
EthernetType: layers.EthernetTypeIPv4,
},
&ipv4,
&udp,
gopacket.Payload(dhcplayer))
if err != nil {
return
dhcp := dhcp4.ReplyPacket(req, mt, serverIP, lease, 24*time.Hour, opt)
if err := udp.SetNetworkLayerForChecksum(&ipv4); err != nil {
log.Error("Error building DHCP response", err)
}
if err := gopacket.SerializeLayers(buf, opts, &eth, &ipv4, &udp, gopacket.Payload(dhcp)); err != nil {
log.Error("Error serializing DHCP response", err)
}
packetData := buf.Bytes()
@ -367,11 +372,10 @@ func sendDHCPReply(req dhcp.Packet, mt dhcp.MessageType, lease net.IP, reqOpt dh
packetLength := make([]byte, 2)
binary.BigEndian.PutUint16(packetLength, uint16(len(packetData)))
util.WriteBinary(fmt.Sprintf("/tmp/dhcp_%d.dat", time.Now().Unix()), packetData)
util.WritePcap(fmt.Sprintf("/tmp/dhcp_%d.pcap", time.Now().Unix()), packetData)
util.WritePcap(fmt.Sprintf("/tmp/dhcp_%d2.pcap", time.Now().Unix()), packetData[36:])
VmWriter.Write(packetLength)
VmWriter.Write(packetData)
if _, err := VmWriter.Write(packetLength); err != nil {
log.Error("Error writing DHCP response length", err)
}
if _, err := VmWriter.Write(packetData); err != nil {
log.Error("Error writing DHCP response data", err)
}
}