TheArchive/tailscale
1
0
Fork 0
mirror of https://github.com/tailscale/tailscale.git synced 2024-11-29 04:55:31 +00:00
Code Issues Packages Projects Releases Wiki Activity

tstest/natlab: refactor HandleEthernetPacketForRouter a bit

Browse Source 
Move all the UDP handling to its own func to remove a bunch of "if
isUDP" checks in a bunch of blocks.

Updates #13038

Change-Id: If71d71b49e57651d15bd307a2233c43751cc8639
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick 2024-08-24 18:43:40 -07:00 committed by Brad Fitzpatrick
parent 3a8cfbc381
commit 6dd1af0d1e
1 changed files with 45 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
tstest/natlab/vnet/vnet.go
View File

@ -1129,7 +1129,7 @@ func (n *network) serializedUDPPacket(src, dst netip.AddrPort, payload []byte, e
return buffer.Bytes(), nil
}
// HandleEthernetPacketForRouter handles an IPv4 packet that is
// HandleEthernetPacketForRouter handles a packet that is
// directed to the router/gateway itself. The packet may be to the
// broadcast MAC address, or to the router's MAC address. The target
// IP may be the router's IP, or an internet (routed) IP.
@ -1140,18 +1140,50 @@ func (n *network) HandleEthernetPacketForRouter(ep EthernetPacket) {
n.logf("dropping non-IP packet: %v", packet)
return
}
srcIP, dstIP := flow.src, flow.dst
dstIP := flow.dst
toForward := dstIP != n.lanIP4.Addr() && dstIP != netip.IPv4Unspecified() && !dstIP.IsLinkLocalUnicast()
udp, isUDP := packet.Layer(layers.LayerTypeUDP).(*layers.UDP)
// Pre-NAT mapping, for DNS/etc responses:
if srcIP.Is6() {
if flow.src.Is6() {
n.macMu.Lock()
mak.Set(&n.macOfIPv6, srcIP, ep.SrcMAC())
mak.Set(&n.macOfIPv6, flow.src, ep.SrcMAC())
n.macMu.Unlock()
}
if udp, ok := packet.Layer(layers.LayerTypeUDP).(*layers.UDP); ok {
n.handleUDPPacketForRouter(ep, udp, toForward, flow)
return
}
if toForward && n.s.shouldInterceptTCP(packet) {
var base *layers.BaseLayer
proto := header.IPv4ProtocolNumber
if v4, ok := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4); ok {
base = &v4.BaseLayer
} else if v6, ok := packet.Layer(layers.LayerTypeIPv6).(*layers.IPv6); ok {
base = &v6.BaseLayer
proto = header.IPv6ProtocolNumber
} else {
panic("not v4, not v6")
}
pktCopy := make([]byte, 0, len(base.Contents)+len(base.Payload))
pktCopy = append(pktCopy, base.Contents...)
pktCopy = append(pktCopy, base.Payload...)
packetBuf := stack.NewPacketBuffer(stack.PacketBufferOptions{
Payload: buffer.MakeWithData(pktCopy),
})
n.linkEP.InjectInbound(proto, packetBuf)
packetBuf.DecRef()
return
}
n.logf("router got unknown packet: %v", packet)
}
func (n *network) handleUDPPacketForRouter(ep EthernetPacket, udp *layers.UDP, toForward bool, flow ipSrcDst) {
packet := ep.gp
srcIP, dstIP := flow.src, flow.dst
if isDHCPRequest(packet) {
res, err := n.s.createDHCPResponse(packet)
if err != nil {
@ -1177,7 +1209,7 @@ func (n *network) HandleEthernetPacketForRouter(ep EthernetPacket) {
return
}
if isUDP && fakeSyslog.Match(dstIP) {
if fakeSyslog.Match(dstIP) {
node, ok := n.nodeForDestIP(srcIP)
if !ok {
return
@ -1190,7 +1222,7 @@ func (n *network) HandleEthernetPacketForRouter(ep EthernetPacket) {
return
}
if !toForward && isNATPMP(packet) {
if dstIP == n.lanIP4.Addr() && isNATPMP(udp) {
n.handleNATPMPRequest(UDPPacket{
Src: netip.AddrPortFrom(srcIP, uint16(udp.SrcPort)),
Dst: netip.AddrPortFrom(dstIP, uint16(udp.DstPort)),
@ -1199,7 +1231,7 @@ func (n *network) HandleEthernetPacketForRouter(ep EthernetPacket) {
return
}
if toForward && isUDP {
if toForward {
src := netip.AddrPortFrom(srcIP, uint16(udp.SrcPort))
dst := netip.AddrPortFrom(dstIP, uint16(udp.DstPort))
buf, err := n.serializedUDPPacket(src, dst, udp.Payload, nil)
@ -1246,36 +1278,14 @@ func (n *network) HandleEthernetPacketForRouter(ep EthernetPacket) {
return
}
if toForward && n.s.shouldInterceptTCP(packet) {
var base *layers.BaseLayer
proto := header.IPv4ProtocolNumber
if v4, ok := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4); ok {
base = &v4.BaseLayer
} else if v6, ok := packet.Layer(layers.LayerTypeIPv6).(*layers.IPv6); ok {
base = &v6.BaseLayer
proto = header.IPv6ProtocolNumber
} else {
panic("not v4, not v6")
}
pktCopy := make([]byte, 0, len(base.Contents)+len(base.Payload))
pktCopy = append(pktCopy, base.Contents...)
pktCopy = append(pktCopy, base.Payload...)
packetBuf := stack.NewPacketBuffer(stack.PacketBufferOptions{
Payload: buffer.MakeWithData(pktCopy),
})
n.linkEP.InjectInbound(proto, packetBuf)
packetBuf.DecRef()
return
}
if isUDP && (udp.DstPort == pcpPort || udp.DstPort == ssdpPort) {
if udp.DstPort == pcpPort || udp.DstPort == ssdpPort {
// We handle NAT-PMP, but not these yet.
// TODO(bradfitz): handle? marginal utility so far.
// Don't log about them being unknown.
return
}
n.logf("router got unknown packet: %v", packet)
n.logf("router got unknown UDP packet: %v", packet)
}
func (n *network) handleIPv6RouterSolicitation(ep EthernetPacket, rs *layers.ICMPv6RouterSolicitation) {
@ -1600,9 +1610,8 @@ func isDNSRequest(pkt gopacket.Packet) bool {
return ok && dns.QR == false && len(dns.Questions) > 0
}
func isNATPMP(pkt gopacket.Packet) bool {
udp, ok := pkt.Layer(layers.LayerTypeUDP).(*layers.UDP)
return ok && udp.DstPort == 5351 && len(udp.Payload) > 0 && udp.Payload[0] == 0 // version 0, not 2 for PCP
func isNATPMP(udp *layers.UDP) bool {
return udp.DstPort == 5351 && len(udp.Payload) > 0 && udp.Payload[0] == 0 // version 0, not 2 for PCP
}
func makeSTUNReply(req UDPPacket) (res UDPPacket, ok bool) {