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tstest/natlab: add unix address to writer for dgram mode

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updates tailcale/corp#22371

For dgram mode, we need to store the write addresses of
the client socket(s) alongside the writer functions and
the write operation needs to use WriteToUnix.

Unix also has multiple clients writing to the same socket,
so the serve method is modified to handle packets from
multiple mac addresses.

Cleans up a bit of cruft from the initial tailmac tooling
commit.

Now all the macOS packets are belong to us.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>
pull/13238/head
Jonathan Nobels 3 months ago committed by Brad Fitzpatrick
parent 743d296073
commit 1191eb0e3d
3 changed files with 84 additions and 131 deletions
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84
tstest/natlab/machost/README.md
Unescape Escape View File

@ -1,84 +0,0 @@
# macOS VM's for tstest and natlab
## Building
```
%make all
```
Will build both the TailMac and the VMHost app. You will need a developer account. The default bundle identifiers
default to tailscale owned ids, so if you don't have (or aren't using) a tailscale dev account, you will need to change this.
This should build automatically as long as you have a valid developer cert. Signing is automatic. The binaries both
require proper entitlements, so they do need to be signed.
There are separate recipes in the makefile to rebuild the individual components if needed.
All binaries are copied to the bin directory.
You can generally do all interactions via the TailMac command line util.
## Locations
Everything is persisted at ~/VM.bundle
Each vm gets it's own directory under there.
RestoreImage.ipsw is used to build new VMs. You may replace this manually if you wish.
Individual parameters for each instance are saved in a json config file (config.json)
## Installing
### Default a parameters
The default virtio socket device port is 51009
The default server socket for the virtual network device is /tmp/qemu.sock
The default memory size is 4Gb
The default mac address for the socket based network is 5a:94:ef:e4:0c:ee
The defualt mac address for normal ethernet is 5a:94:ef:e4:0c:ef
All of these parameters are configurable.
### Creating and managing VMs
To create a new VM (this will grab a restore image if needed). Restore images are large. Installation takes a minute
```
TailMac create --id my_vm_id
```
To delete a new VM
```
TailMac delete --id my_vm_id
```
To refresh an existing restore image:
```
TailMac refresh
```
To clone an existing vm (this will clone the mac and port as well)
```
TailMac clone --id old_vm_id --target-id new_vm_id
```
To reconfigure a vm with a specific mac and a virtio socket device port:
```
TailMac configure --id vm_id --mac 11:22:33:44:55:66 --port 12345 --ethermac 22:33:44:55:66:77 --mem 4000000000 --sock "/var/netdevice.sock"
```
## Running a VM
MacHost is an app bundle, but the main binary behaves as a command line util. You can invoke it
thusly:
```
TailMac --id machine_1
```
You may invoke multiple vms, but the limit on the number of concurrent instances is on the order of 2.
To stop a running VM (this is a fire and forget thing):
```
TailMac stop --id machine_1
```

111
tstest/natlab/vnet/vnet.go
Unescape Escape View File

@ -222,8 +222,8 @@ func (n *network) initStack() error {
log.Printf("Serialize error: %v", err) log.Printf("Serialize error: %v", err)
continue continue
} }
if writeFunc, ok := n.writeFunc.Load(node.mac); ok { if nw, ok := n.writers.Load(node.mac); ok {
writeFunc(buffer.Bytes()) nw.write(buffer.Bytes())
} else { } else {
log.Printf("No writeFunc for %v", node.mac) log.Printf("No writeFunc for %v", node.mac)
} }
@ -465,6 +465,20 @@ type portMapping struct {
expiry time.Time expiry time.Time
} }
type writerFunc func([]byte, *net.UnixAddr, int)
// Encapsulates both a write function, an optional outbound socket address
// for dgram mode and an interfaceID for packet captures.
type networkWriter struct {
writer writerFunc // Function to write packets to the network
addr *net.UnixAddr // Outbound socket address for dgram mode
interfaceID int // The interface ID of the src node (for writing pcaps)
}
func (nw *networkWriter) write(b []byte) {
nw.writer(b, nw.addr, nw.interfaceID)
}
type network struct { type network struct {
s *Server s *Server
mac MAC mac MAC
@ -485,16 +499,23 @@ type network struct {
portMap map[netip.AddrPort]portMapping // WAN ip:port -> LAN ip:port portMap map[netip.AddrPort]portMapping // WAN ip:port -> LAN ip:port
portMapFlow map[portmapFlowKey]netip.AddrPort // (lanAP, peerWANAP) -> portmapped wanAP portMapFlow map[portmapFlowKey]netip.AddrPort // (lanAP, peerWANAP) -> portmapped wanAP
// writeFunc is a map of MAC -> func to write to that MAC. // writers is a map of MAC -> networkWriters to write packets to that MAC.
// It contains entries for connected nodes only. // It contains entries for connected nodes only.
writeFunc syncs.Map[MAC, func([]byte)] // MAC -> func to write to that MAC writers syncs.Map[MAC, networkWriter] // MAC -> to networkWriter for that MAC
} }
func (n *network) registerWriter(mac MAC, f func([]byte)) { // Regsiters a writerFunc for a MAC address.
if f != nil { // raddr is and optional outbound socket address of the client interface for dgram mode.
n.writeFunc.Store(mac, f) // Pass nil for the writerFunc to deregister the writer.
func (n *network) registerWriter(mac MAC, raddr *net.UnixAddr, interfaceID int, wf writerFunc) {
if wf != nil {
n.writers.Store(mac, networkWriter{
writer: wf,
addr: raddr,
interfaceID: interfaceID,
})
} else { } else {
n.writeFunc.Delete(mac) n.writers.Delete(mac)
} }
} }
@ -684,10 +705,10 @@ type Protocol int
const ( const (
ProtocolQEMU = Protocol(iota + 1) ProtocolQEMU = Protocol(iota + 1)
ProtocolUnixDGRAM // for macOS Hypervisor.Framework and VZFileHandleNetworkDeviceAttachment ProtocolUnixDGRAM // for macOS Virtualization.Framework and VZFileHandleNetworkDeviceAttachment
) )
// serveConn serves a single connection from a client. // Handles a single connection from a QEMU-style client or muxd connections for dgram mode
func (s *Server) ServeUnixConn(uc *net.UnixConn, proto Protocol) { func (s *Server) ServeUnixConn(uc *net.UnixConn, proto Protocol) {
if s.shuttingDown.Load() { if s.shuttingDown.Load() {
return return
@ -702,24 +723,37 @@ func (s *Server) ServeUnixConn(uc *net.UnixConn, proto Protocol) {
bw := bufio.NewWriterSize(uc, 2<<10) bw := bufio.NewWriterSize(uc, 2<<10)
var writeMu sync.Mutex var writeMu sync.Mutex
var srcNode *node writePkt := func(pkt []byte, raddr *net.UnixAddr, interfaceID int) {
writePkt := func(pkt []byte) {
if pkt == nil { if pkt == nil {
return return
} }
writeMu.Lock() writeMu.Lock()
defer writeMu.Unlock() defer writeMu.Unlock()
if proto == ProtocolQEMU { switch proto {
case ProtocolQEMU:
hdr := binary.BigEndian.AppendUint32(bw.AvailableBuffer()[:0], uint32(len(pkt))) hdr := binary.BigEndian.AppendUint32(bw.AvailableBuffer()[:0], uint32(len(pkt)))
if _, err := bw.Write(hdr); err != nil { if _, err := bw.Write(hdr); err != nil {
log.Printf("Write hdr: %v", err) log.Printf("Write hdr: %v", err)
return return
} }
}
if _, err := bw.Write(pkt); err != nil { if _, err := bw.Write(pkt); err != nil {
log.Printf("Write pkt: %v", err) log.Printf("Write pkt: %v", err)
return return
}
case ProtocolUnixDGRAM:
if raddr == nil {
log.Printf("Write pkt: dgram mode write failure, no outbound socket address")
return
} }
if _, err := uc.WriteToUnix(pkt, raddr); err != nil {
log.Printf("Write pkt : %v", err)
return
}
}
if err := bw.Flush(); err != nil { if err := bw.Flush(); err != nil {
log.Printf("Flush: %v", err) log.Printf("Flush: %v", err)
} }
@ -727,22 +761,25 @@ func (s *Server) ServeUnixConn(uc *net.UnixConn, proto Protocol) {
Timestamp: time.Now(), Timestamp: time.Now(),
CaptureLength: len(pkt), CaptureLength: len(pkt),
Length: len(pkt), Length: len(pkt),
InterfaceIndex: srcNode.interfaceID, InterfaceIndex: interfaceID,
}, pkt)) }, pkt))
} }
buf := make([]byte, 16<<10) buf := make([]byte, 16<<10)
var netw *network // non-nil after first packet
for { for {
var packetRaw []byte var packetRaw []byte
if proto == ProtocolUnixDGRAM { var raddr *net.UnixAddr
n, _, err := uc.ReadFromUnix(buf)
switch proto {
case ProtocolUnixDGRAM:
n, addr, err := uc.ReadFromUnix(buf)
raddr = addr
if err != nil { if err != nil {
log.Printf("ReadFromUnix: %v", err) log.Printf("ReadFromUnix: %v", err)
continue continue
} }
packetRaw = buf[:n] packetRaw = buf[:n]
} else if proto == ProtocolQEMU { case ProtocolQEMU:
if _, err := io.ReadFull(uc, buf[:4]); err != nil { if _, err := io.ReadFull(uc, buf[:4]); err != nil {
if s.shutdownCtx.Err() != nil { if s.shutdownCtx.Err() != nil {
// Return without logging. // Return without logging.
@ -772,29 +809,29 @@ func (s *Server) ServeUnixConn(uc *net.UnixConn, proto Protocol) {
ep := EthernetPacket{le, packet} ep := EthernetPacket{le, packet}
srcMAC := ep.SrcMAC() srcMAC := ep.SrcMAC()
if srcNode == nil { srcNode, ok := s.nodeByMAC[srcMAC]
srcNode, ok = s.nodeByMAC[srcMAC]
if !ok { if !ok {
log.Printf("[conn %p] ignoring frame from unknown MAC %v", uc, srcMAC) log.Printf("[conn %p] got frame from unknown MAC %v", uc, srcMAC)
continue continue
} }
log.Printf("[conn %p] MAC %v is node %v", uc, srcMAC, srcNode.lanIP)
netw = srcNode.net // Register a writer for the source MAC address if one doesn't exist.
netw.registerWriter(srcMAC, writePkt) if _, ok := srcNode.net.writers.Load(srcMAC); !ok {
defer netw.registerWriter(srcMAC, nil) log.Printf("[conn %p] Registering writer for MAC %v is node %v", uc, srcMAC, srcNode.lanIP)
} else { srcNode.net.registerWriter(srcMAC, raddr, srcNode.interfaceID, writePkt)
if srcMAC != srcNode.mac { defer func() {
log.Printf("[conn %p] ignoring frame from MAC %v, expected %v", uc, srcMAC, srcNode.mac) srcNode.net.registerWriter(srcMAC, nil, 0, nil)
}()
continue continue
} }
}
must.Do(s.pcapWriter.WritePacket(gopacket.CaptureInfo{ must.Do(s.pcapWriter.WritePacket(gopacket.CaptureInfo{
Timestamp: time.Now(), Timestamp: time.Now(),
CaptureLength: len(packetRaw), CaptureLength: len(packetRaw),
Length: len(packetRaw), Length: len(packetRaw),
InterfaceIndex: srcNode.interfaceID, InterfaceIndex: srcNode.interfaceID,
}, packetRaw)) }, packetRaw))
netw.HandleEthernetPacket(ep) srcNode.net.HandleEthernetPacket(ep)
} }
} }
@ -839,8 +876,8 @@ func (n *network) writeEth(res []byte) {
dstMAC := MAC(res[0:6]) dstMAC := MAC(res[0:6])
srcMAC := MAC(res[6:12]) srcMAC := MAC(res[6:12])
if dstMAC.IsBroadcast() { if dstMAC.IsBroadcast() {
n.writeFunc.Range(func(mac MAC, writeFunc func([]byte)) bool { n.writers.Range(func(mac MAC, nw networkWriter) bool {
writeFunc(res) nw.write(res)
return true return true
}) })
return return
@ -849,8 +886,8 @@ func (n *network) writeEth(res []byte) {
n.logf("dropping write of packet from %v to itself", srcMAC) n.logf("dropping write of packet from %v to itself", srcMAC)
return return
} }
if writeFunc, ok := n.writeFunc.Load(dstMAC); ok { if nw, ok := n.writers.Load(dstMAC); ok {
writeFunc(res) nw.write(res)
return return
} }
} }

6
tstest/tailmac/TailMac.xcodeproj/xcshareddata/xcschemes/host.xcscheme
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@ -15,7 +15,7 @@
<BuildableReference <BuildableReference
BuildableIdentifier = "primary" BuildableIdentifier = "primary"
BlueprintIdentifier = "8F87D51C26C34111000EADA4" BlueprintIdentifier = "8F87D51C26C34111000EADA4"
BuildableName = "TailMac.app" BuildableName = "Host.app"
BlueprintName = "host" BlueprintName = "host"
ReferencedContainer = "container:TailMac.xcodeproj"> ReferencedContainer = "container:TailMac.xcodeproj">
</BuildableReference> </BuildableReference>
@ -45,7 +45,7 @@
<BuildableReference <BuildableReference
BuildableIdentifier = "primary" BuildableIdentifier = "primary"
BlueprintIdentifier = "8F87D51C26C34111000EADA4" BlueprintIdentifier = "8F87D51C26C34111000EADA4"
BuildableName = "TailMac.app" BuildableName = "Host.app"
BlueprintName = "host" BlueprintName = "host"
ReferencedContainer = "container:TailMac.xcodeproj"> ReferencedContainer = "container:TailMac.xcodeproj">
</BuildableReference> </BuildableReference>
@ -62,7 +62,7 @@
<BuildableReference <BuildableReference
BuildableIdentifier = "primary" BuildableIdentifier = "primary"
BlueprintIdentifier = "8F87D51C26C34111000EADA4" BlueprintIdentifier = "8F87D51C26C34111000EADA4"
BuildableName = "TailMac.app" BuildableName = "Host.app"
BlueprintName = "host" BlueprintName = "host"
ReferencedContainer = "container:TailMac.xcodeproj"> ReferencedContainer = "container:TailMac.xcodeproj">
</BuildableReference> </BuildableReference>

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