nebula/e2e/router/router.go

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//go:build e2e_testing
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// +build e2e_testing
package router
import (
"fmt"
"net"
"reflect"
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"strconv"
"sync"
"github.com/slackhq/nebula"
"github.com/slackhq/nebula/header"
"github.com/slackhq/nebula/udp"
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)
type R struct {
// Simple map of the ip:port registered on a control to the control
// Basically a router, right?
controls map[string]*nebula.Control
// A map for inbound packets for a control that doesn't know about this address
inNat map[string]*nebula.Control
// A last used map, if an inbound packet hit the inNat map then
// all return packets should use the same last used inbound address for the outbound sender
// map[from address + ":" + to address] => ip:port to rewrite in the udp packet to receiver
outNat map[string]net.UDPAddr
// All interactions are locked to help serialize behavior
sync.Mutex
}
type ExitType int
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const (
// Keeps routing, the function will get called again on the next packet
KeepRouting ExitType = 0
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// Does not route this packet and exits immediately
ExitNow ExitType = 1
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// Routes this packet and exits immediately afterwards
RouteAndExit ExitType = 2
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)
type ExitFunc func(packet *udp.Packet, receiver *nebula.Control) ExitType
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func NewR(controls ...*nebula.Control) *R {
r := &R{
controls: make(map[string]*nebula.Control),
inNat: make(map[string]*nebula.Control),
outNat: make(map[string]net.UDPAddr),
}
for _, c := range controls {
addr := c.GetUDPAddr()
if _, ok := r.controls[addr]; ok {
panic("Duplicate listen address: " + addr)
}
r.controls[addr] = c
}
return r
}
// AddRoute will place the nebula controller at the ip and port specified.
// It does not look at the addr attached to the instance.
// If a route is used, this will behave like a NAT for the return path.
// Rewriting the source ip:port to what was last sent to from the origin
func (r *R) AddRoute(ip net.IP, port uint16, c *nebula.Control) {
r.Lock()
defer r.Unlock()
inAddr := net.JoinHostPort(ip.String(), fmt.Sprintf("%v", port))
if _, ok := r.inNat[inAddr]; ok {
panic("Duplicate listen address inNat: " + inAddr)
}
r.inNat[inAddr] = c
}
// OnceFrom will route a single packet from sender then return
// If the router doesn't have the nebula controller for that address, we panic
func (r *R) OnceFrom(sender *nebula.Control) {
r.RouteExitFunc(sender, func(*udp.Packet, *nebula.Control) ExitType {
return RouteAndExit
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})
}
// RouteUntilTxTun will route for sender and return when a packet is seen on receivers tun
// If the router doesn't have the nebula controller for that address, we panic
func (r *R) RouteUntilTxTun(sender *nebula.Control, receiver *nebula.Control) []byte {
tunTx := receiver.GetTunTxChan()
udpTx := sender.GetUDPTxChan()
for {
select {
// Maybe we already have something on the tun for us
case b := <-tunTx:
return b
// Nope, lets push the sender along
case p := <-udpTx:
outAddr := sender.GetUDPAddr()
r.Lock()
inAddr := net.JoinHostPort(p.ToIp.String(), fmt.Sprintf("%v", p.ToPort))
c := r.getControl(outAddr, inAddr, p)
if c == nil {
r.Unlock()
panic("No control for udp tx")
}
c.InjectUDPPacket(p)
r.Unlock()
}
}
}
// RouteExitFunc will call the whatDo func with each udp packet from sender.
// whatDo can return:
// - exitNow: the packet will not be routed and this call will return immediately
// - routeAndExit: this call will return immediately after routing the last packet from sender
// - keepRouting: the packet will be routed and whatDo will be called again on the next packet from sender
func (r *R) RouteExitFunc(sender *nebula.Control, whatDo ExitFunc) {
h := &header.H{}
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for {
p := sender.GetFromUDP(true)
r.Lock()
if err := h.Parse(p.Data); err != nil {
panic(err)
}
outAddr := sender.GetUDPAddr()
inAddr := net.JoinHostPort(p.ToIp.String(), fmt.Sprintf("%v", p.ToPort))
receiver := r.getControl(outAddr, inAddr, p)
if receiver == nil {
r.Unlock()
panic("Can't route for host: " + inAddr)
}
e := whatDo(p, receiver)
switch e {
case ExitNow:
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r.Unlock()
return
case RouteAndExit:
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receiver.InjectUDPPacket(p)
r.Unlock()
return
case KeepRouting:
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receiver.InjectUDPPacket(p)
default:
panic(fmt.Sprintf("Unknown exitFunc return: %v", e))
}
r.Unlock()
}
}
// RouteUntilAfterMsgType will route for sender until a message type is seen and sent from sender
// If the router doesn't have the nebula controller for that address, we panic
func (r *R) RouteUntilAfterMsgType(sender *nebula.Control, msgType header.MessageType, subType header.MessageSubType) {
h := &header.H{}
r.RouteExitFunc(sender, func(p *udp.Packet, r *nebula.Control) ExitType {
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if err := h.Parse(p.Data); err != nil {
panic(err)
}
if h.Type == msgType && h.Subtype == subType {
return RouteAndExit
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}
return KeepRouting
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})
}
// RouteForUntilAfterToAddr will route for sender and return only after it sees and sends a packet destined for toAddr
// finish can be any of the exitType values except `keepRouting`, the default value is `routeAndExit`
// If the router doesn't have the nebula controller for that address, we panic
func (r *R) RouteForUntilAfterToAddr(sender *nebula.Control, toAddr *net.UDPAddr, finish ExitType) {
if finish == KeepRouting {
finish = RouteAndExit
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}
r.RouteExitFunc(sender, func(p *udp.Packet, r *nebula.Control) ExitType {
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if p.ToIp.Equal(toAddr.IP) && p.ToPort == uint16(toAddr.Port) {
return finish
}
return KeepRouting
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})
}
// RouteForAllExitFunc will route for every registered controller and calls the whatDo func with each udp packet from
// whatDo can return:
// - exitNow: the packet will not be routed and this call will return immediately
// - routeAndExit: this call will return immediately after routing the last packet from sender
// - keepRouting: the packet will be routed and whatDo will be called again on the next packet from sender
func (r *R) RouteForAllExitFunc(whatDo ExitFunc) {
sc := make([]reflect.SelectCase, len(r.controls))
cm := make([]*nebula.Control, len(r.controls))
i := 0
for _, c := range r.controls {
sc[i] = reflect.SelectCase{
Dir: reflect.SelectRecv,
Chan: reflect.ValueOf(c.GetUDPTxChan()),
Send: reflect.Value{},
}
cm[i] = c
i++
}
for {
x, rx, _ := reflect.Select(sc)
r.Lock()
p := rx.Interface().(*udp.Packet)
outAddr := cm[x].GetUDPAddr()
inAddr := net.JoinHostPort(p.ToIp.String(), fmt.Sprintf("%v", p.ToPort))
receiver := r.getControl(outAddr, inAddr, p)
if receiver == nil {
r.Unlock()
panic("Can't route for host: " + inAddr)
}
e := whatDo(p, receiver)
switch e {
case ExitNow:
r.Unlock()
return
case RouteAndExit:
receiver.InjectUDPPacket(p)
r.Unlock()
return
case KeepRouting:
receiver.InjectUDPPacket(p)
default:
panic(fmt.Sprintf("Unknown exitFunc return: %v", e))
}
r.Unlock()
}
}
// FlushAll will route for every registered controller, exiting once there are no packets left to route
func (r *R) FlushAll() {
sc := make([]reflect.SelectCase, len(r.controls))
cm := make([]*nebula.Control, len(r.controls))
i := 0
for _, c := range r.controls {
sc[i] = reflect.SelectCase{
Dir: reflect.SelectRecv,
Chan: reflect.ValueOf(c.GetUDPTxChan()),
Send: reflect.Value{},
}
cm[i] = c
i++
}
// Add a default case to exit when nothing is left to send
sc = append(sc, reflect.SelectCase{
Dir: reflect.SelectDefault,
Chan: reflect.Value{},
Send: reflect.Value{},
})
for {
x, rx, ok := reflect.Select(sc)
if !ok {
return
}
r.Lock()
p := rx.Interface().(*udp.Packet)
outAddr := cm[x].GetUDPAddr()
inAddr := net.JoinHostPort(p.ToIp.String(), fmt.Sprintf("%v", p.ToPort))
receiver := r.getControl(outAddr, inAddr, p)
if receiver == nil {
r.Unlock()
panic("Can't route for host: " + inAddr)
}
r.Unlock()
}
}
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// getControl performs or seeds NAT translation and returns the control for toAddr, p from fields may change
// This is an internal router function, the caller must hold the lock
func (r *R) getControl(fromAddr, toAddr string, p *udp.Packet) *nebula.Control {
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if newAddr, ok := r.outNat[fromAddr+":"+toAddr]; ok {
p.FromIp = newAddr.IP
p.FromPort = uint16(newAddr.Port)
}
c, ok := r.inNat[toAddr]
if ok {
sHost, sPort, err := net.SplitHostPort(toAddr)
if err != nil {
panic(err)
}
port, err := strconv.Atoi(sPort)
if err != nil {
panic(err)
}
r.outNat[c.GetUDPAddr()+":"+fromAddr] = net.UDPAddr{
IP: net.ParseIP(sHost),
Port: port,
}
return c
}
return r.controls[toAddr]
}