func TestProtocolHandler(t *testing.T) {
var (
answers = rand.Intn(12) + 3
want = answers / 2
testHandler = dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
res := &dns.Msg{}
for i := 0; i < answers; i++ {
rr := &dns.A{
Hdr: dns.RR_Header{
Name: r.Question[0].Name,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 5,
},
A: net.ParseIP(fmt.Sprintf("1.2.3.%d", i)),
}
res.Answer = append(res.Answer, rr)
}
err := w.WriteMsg(res)
if err != nil {
t.Fatalf("write response failed: %s", err)
}
})
)
w := &testWriter{
remoteAddr: &net.UDPAddr{},
}
m := &dns.Msg{}
m.SetQuestion(dns.Fqdn("app.glimpse.io"), dns.TypeA)
protocolHandler(want, testHandler).ServeDNS(w, m)
if have := len(w.msg.Answer); want != have {
t.Errorf("want %d answers, have %d", want, have)
}
e := &errorWriter{w}
errorHandler := dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
err := w.WriteMsg(&dns.Msg{})
if err == nil {
t.Fatalf("want WriteMsg() to fail with errorWriter")
}
})
m = &dns.Msg{}
m.SetQuestion(dns.Fqdn("app.glimpse.io"), dns.TypeA)
protocolHandler(42, errorHandler).ServeDNS(e, m)
}
func (s *Server) systemdServe() {
// We will usually have at least one TCP socket and one UDP socket.
// PacketConns are UDP sockets, Listeners are TCP sockets.
// To make things more annoying, both can (and usually will) have nil
// entries for the file descriptors that don't match.
pconns, err := activation.PacketConns(false)
if err != nil {
glog.Fatalf("Error getting systemd packet conns: %v", err)
}
listeners, err := activation.Listeners(false)
if err != nil {
glog.Fatalf("Error getting systemd listeners: %v", err)
}
var wg sync.WaitGroup
for _, pconn := range pconns {
if pconn == nil {
continue
}
wg.Add(1)
go func(c net.PacketConn) {
defer wg.Done()
glog.Infof("Activate on packet connection (UDP)")
err := dns.ActivateAndServe(nil, c, dns.HandlerFunc(s.Handler))
glog.Fatalf("Exiting UDP listener: %v", err)
}(pconn)
}
for _, lis := range listeners {
if lis == nil {
continue
}
wg.Add(1)
go func(l net.Listener) {
defer wg.Done()
glog.Infof("Activate on listening socket (TCP)")
err := dns.ActivateAndServe(l, nil, dns.HandlerFunc(s.Handler))
glog.Fatalf("Exiting TCP listener: %v", err)
}(lis)
}
wg.Wait()
// We should only get here if there were no useful sockets.
glog.Fatalf("No systemd sockets, did you forget the .socket?")
}
func TestDNSLoggingHandlerError(t *testing.T) {
var (
b = &bytes.Buffer{}
l = log.New(b, "glimpse-agent ", log.Lmicroseconds)
m = &dns.Msg{}
e = &errorWriter{
&testWriter{
remoteAddr: &net.UDPAddr{},
},
}
errorHandler = dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
err := w.WriteMsg(&dns.Msg{})
if err == nil {
t.Fatalf("want WriteMsg() to fail with errorWriter")
}
})
)
m.SetQuestion(dns.Fqdn("app.glimpse.io"), dns.TypeA)
dnsLoggingHandler(l, errorHandler).ServeDNS(e, m)
sp := strings.SplitN(strings.Trim(b.String(), "\n"), " ", 10)
if want, have := "error: failed write", sp[9]; want != have {
t.Errorf("want %#v, have %#v", want, have)
}
}
func (c *MDNSClient) Start(ifi *net.Interface) (err error) {
if c.running {
return nil
}
if c.conn, err = net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0}); err != nil {
return err
}
multicast, err := LinkLocalMulticastListener(ifi)
if err != nil {
return err
}
handleMDNS := func(w dns.ResponseWriter, r *dns.Msg) {
// Don't want to handle queries here, so filter anything out that isn't a response
if len(r.Answer) > 0 {
c.ResponseCallback(r)
}
}
c.listener = &dns.Server{Unsafe: true, PacketConn: multicast, Handler: dns.HandlerFunc(handleMDNS)}
go c.listener.ActivateAndServe()
actionChan := make(chan MDNSAction, MailboxSize)
c.actionChan = actionChan
go c.actorLoop(actionChan)
return nil
}
func TestDNSLoggingHandler(t *testing.T) {
var (
b = &bytes.Buffer{}
l = log.New(b, "glimpse-agent ", log.Lmicroseconds)
fqdn = dns.Fqdn("db.glimpse.io")
w = &testWriter{
remoteAddr: &net.UDPAddr{
IP: net.ParseIP("8.7.6.5"),
Port: 4321,
},
}
testHandler = dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
res := &dns.Msg{}
res.SetReply(req)
res.SetRcode(req, dns.RcodeNotImplemented)
err := w.WriteMsg(res)
if err != nil {
t.Fatalf("write response failed: %s", err)
}
})
)
m := &dns.Msg{}
m.SetQuestion(fqdn, dns.TypeA)
dnsLoggingHandler(l, testHandler).ServeDNS(w, m)
sp := strings.SplitN(strings.Trim(b.String(), "\n"), " ", 10)
if want, have := 9, len(sp); want != have {
t.Fatalf("want %d fields, have %d fields", want, have)
}
if want, have := "DNS", sp[2]; want != have {
t.Errorf("want %s, have %s", want, have)
}
if want, have := "8.7.6.5:4321", sp[4]; want != have {
t.Errorf("want %s, have %s", want, have)
}
if want, have := "A", sp[5]; want != have {
t.Errorf("want %s, have %s", want, have)
}
if want, have := fqdn, sp[6]; want != have {
t.Errorf("want %s, have %s", want, have)
}
if want, have := dns.RcodeToString[dns.RcodeNotImplemented], sp[7]; want != have {
t.Errorf("want %s, have %s", want, have)
}
if want, have := "0", sp[8]; want != have {
t.Errorf("want %s, have %s", want, have)
}
}
func main() {
var listenports, ipranges StringList
var remote = flag.Bool("remote", false, "Run as the remote-end of the tunnel.")
var dnsaddr = flag.String("dns-addr", ":53", "Listen address for local DNS server.")
flag.Var(&ipranges, "iprange", "The IP address range to use for the proxy pool. Acceptable "+
"values are CIDR-style network addresses & single IP addresses. Can be set multiple "+
"times for multiple ranges.")
flag.Var(&listenports, "port", "TCP port to proxy. Can be set multiple times for multiple "+
"ports.")
flag.StringVar(&tunneladdr, "tunnel-addr", "", "Address for the remote-end of the tunnel.")
flag.StringVar(&dnsserver, "upstream-dns-server", "8.8.8.8:53", "DNS server to rely our "+
"incoming requests to.")
flag.Parse()
if *remote {
log.Fatal(listenAndTunnel(tunneladdr))
}
addrpool.pool.OnEvicted = func(key lru.Key, value interface{}) {
log.Printf("Evicting %s -> %v", uint32toip4(key.(uint32)), value.(string))
addrpool.freeaddr = uint32toip4(key.(uint32))
delete(addrpool.domains, value.(string))
}
// We pass IPs onto this channel as we parse them.
ipchan := make(chan uint32)
go func() {
for ip := range ipchan {
log.Printf("Adding %v", uint32toip4(ip))
addrpool.pool.Add(ip, "--invalid--")
for _, port := range listenports {
go listenAndProxy(uint32toip4(ip).String() + ":" + port)
}
}
}()
for _, r := range ipranges {
if err := parseCIDR(r, ipchan); err == nil {
continue
}
if err := parseIP(r, ipchan); err == nil {
continue
}
// TODO nmap-style octet addressing ip-range parsing.
log.Fatalf("Couldn't parse address range %v", r)
}
close(ipchan)
server := &dns.Server{
Addr: *dnsaddr,
Net: "udp",
Handler: dns.HandlerFunc(resolver),
}
log.Fatal(server.ListenAndServe())
}
// NewServer creates a new Server with the given options.
func NewServer(o Options) (*Server, error) {
if err := o.validate(); err != nil {
return nil, err
}
s := Server{
c: &dns.Client{},
s: &dns.Server{
Net: o.Net,
Addr: o.Bind,
},
white: o.Whitelist != "",
hosts: hosts{},
hostsRX: hostsRX{},
privateHosts: map[string]struct{}{},
privateHostsRX: map[string]*regexp.Regexp{},
}
hostListPath := o.Whitelist
if hostListPath == "" {
hostListPath = o.Blacklist
}
s.hostsFile.path = hostListPath
if err := s.loadHostEntries(); err != nil {
return nil, err
}
if o.Poll != 0 {
go s.monitorHostEntries(o.Poll)
}
s.s.Handler = dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
// If no upstream proxy is present, drop the query:
if len(o.Resolve) == 0 {
dns.HandleFailed(w, r)
return
}
// Filter Questions:
if r.Question = s.filter(r.Question); len(r.Question) == 0 {
w.WriteMsg(r)
return
}
// Proxy Query:
for _, addr := range o.Resolve {
in, _, err := s.c.Exchange(r, addr)
if err != nil {
continue
}
w.WriteMsg(in)
return
}
dns.HandleFailed(w, r)
})
return &s, nil
}
func (d *DNS) ListenAndServe() error {
udpErr := make(chan error)
tcpErr := make(chan error)
go func() {
udpErr <- dns.ListenAndServe(d.Config.Bind, "udp", dns.HandlerFunc(d.handler))
}()
go func() {
tcpErr <- dns.ListenAndServe(d.Config.Bind, "tcp", dns.HandlerFunc(d.handler))
}()
select {
case err := <-udpErr:
return err
case err := <-tcpErr:
return err
}
return nil
}
func TestDnsMetricsHandler(t *testing.T) {
testHandler := dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
res := &dns.Msg{}
res.SetReply(req)
res.SetRcode(req, dns.RcodeNotImplemented)
err := w.WriteMsg(res)
if err != nil {
t.Fatalf("write response failed: %s", err)
}
})
w := &testWriter{
remoteAddr: &net.UDPAddr{},
}
m := &dns.Msg{}
m.SetQuestion(dns.Fqdn("app.glimpse.io"), dns.TypeA)
dnsMetricsHandler(testHandler).ServeDNS(w, m)
r := w.msg
if want, have := dns.RcodeNotImplemented, r.Rcode; want != have {
t.Errorf(
"want rcode %s, have %s",
dns.RcodeToString[want],
dns.RcodeToString[have],
)
}
e := &errorWriter{w}
errorHandler := dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
err := w.WriteMsg(&dns.Msg{})
if err == nil {
t.Fatalf("want WriteMsg() to fail with errorWriter")
}
})
m = &dns.Msg{}
m.SetQuestion(dns.Fqdn("app.glimpse.io"), dns.TypeA)
dnsMetricsHandler(errorHandler).ServeDNS(e, m)
}
func NewServer() Server {
server := Server{
records: make(map[string][]miekgdns.RR),
truncatedDomainNames: make(map[string]bool),
}
server.udpServer = &miekgdns.Server{
Addr: ":53",
Net: "udp",
Handler: miekgdns.HandlerFunc(server.handleUDPDNSRequest),
}
server.tcpServer = &miekgdns.Server{
Addr: ":53",
Net: "tcp",
Handler: miekgdns.HandlerFunc(server.handleTCPDNSRequest),
}
return server
}
func initDNS() {
if GConf.LocalDNS.CacheSize > 0 {
dnsCache, _ = lru.New(GConf.LocalDNS.CacheSize)
}
if len(GConf.LocalDNS.Listen) > 0 {
err := dns.ListenAndServe(GConf.LocalDNS.Listen, "udp", dns.HandlerFunc(proxyDNS))
if nil != err {
log.Printf("Failed to start dns server:%v", err)
}
}
}
func (s *Server) classicServe() {
glog.Infof("DNS listening on %s", s.Addr)
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
err := dns.ListenAndServe(s.Addr, "udp", dns.HandlerFunc(s.Handler))
glog.Fatalf("Exiting UDP: %v", err)
}()
wg.Add(1)
go func() {
defer wg.Done()
err := dns.ListenAndServe(s.Addr, "tcp", dns.HandlerFunc(s.Handler))
glog.Fatalf("Exiting TCP: %v", err)
}()
wg.Wait()
}
func dnsDispatch() {
udpConn, err := net.ListenUDP("udp", dnsThis)
if err != nil {
kilog.Critical("%v", err.Error())
os.Exit(-1)
}
// hack to make Windows happy
nameToIP["dns.msftncsi.com."] = "131.107.255.255"
dns.ActivateAndServe(nil, udpConn, dns.HandlerFunc(dnsHandle))
}
func RunLocalMulticastServer() (*dns.Server, error) {
multicast, err := LinkLocalMulticastListener(nil)
if err != nil {
return nil, err
}
server := &dns.Server{
PacketConn: multicast,
Handler: dns.HandlerFunc(minimalServer),
ReadTimeout: 100 * time.Millisecond}
go server.ActivateAndServe()
return server, nil
}
func (s HelixServer) Start() {
server := &dns.Server{
Addr: ":" + strconv.Itoa(s.Port),
Net: "udp",
Handler: dns.HandlerFunc(s.Handler),
ReadTimeout: 10,
WriteTimeout: 10,
}
log.Print("Starting server...")
server.ListenAndServe()
}
// TvproxySrv is the main exported method to run the dns server
// It will forward requests we're not interested in, otherwise it'll
// intercept for us and return the external address of this server as
// specified in the config
func TvproxySrv(port string) {
pc, err := net.ListenPacket("udp", port)
if err != nil {
fmt.Printf("Cannot listen on address %s", port)
return
}
fmt.Printf("Starting server on %s\n", port)
srv := &dns.Server{Addr: port, Net: "udp", PacketConn: pc, Handler: dns.HandlerFunc(interceptRequest)}
defer srv.Shutdown()
// periodically update the cache
//go refreshCache()
// start the dns server. Ctrl + C (etc) to kill
srv.ActivateAndServe()
}
func (s *dnsServer) ListenAndServe() {
var err error
s.answerRR, err = dns.NewRR("test.blah A 1.2.3.4")
if err != nil {
panic(err)
}
s.srv = &dns.Server{
Addr: s.Addr,
Net: "udp",
Handler: dns.HandlerFunc(s.Handler),
}
err = s.srv.ListenAndServe()
if err != nil {
panic(err)
}
}
func main() {
var addr = flag.String("addr", "127.0.0.1:5300", "listen address")
var ip = flag.String("ip", "127.0.0.1", "resolve ipv4 address")
flag.Parse()
resolveIP = net.ParseIP(*ip)
if resolveIP == nil {
log.Fatalf("Invalid ip address: %s\n", *ip)
}
if resolveIP.To4() == nil {
log.Fatalf("Invalid ipv4 address: %s\n", *ip)
}
server := &dns.Server{Addr: *addr, Net: "udp"}
server.Handler = dns.HandlerFunc(handleRequest)
log.Printf("Listening on %s, resolving to %s\n", *addr, *ip)
log.Fatal(server.ListenAndServe())
}
func startUpstreamTestServer(c *C) (string, string, func()) {
h := dns.HandlerFunc(func(w dns.ResponseWriter, req *dns.Msg) {
res := &dns.Msg{}
res.SetReply(req)
switch req.Question[0].Name {
case "long-compressed-response.":
for i := 0; i < 25; i++ {
res.Answer = append(res.Answer, &dns.A{
Hdr: dns.RR_Header{
Name: req.Question[0].Name,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
},
A: net.IP{192, 168, 0, byte(i)},
})
}
if res.Len() <= 512 {
panic("not huge")
}
res.Compress = true
if res.Len() > 512 {
panic("too big compressed")
}
w.WriteMsg(res)
}
})
up := make(chan struct{}, 2)
notifyStart := func() { up <- struct{}{} }
udpListener, err := net.ListenPacket("udp4", "127.0.0.1:0")
c.Assert(err, IsNil)
udp := &dns.Server{
Net: "udp",
PacketConn: udpListener,
Handler: h,
NotifyStartedFunc: notifyStart,
}
go udp.ActivateAndServe()
tcpListener, err := net.Listen("tcp4", "127.0.0.1:0")
c.Assert(err, IsNil)
tcp := &dns.Server{
Net: "tcp",
Listener: tcpListener,
Handler: h,
NotifyStartedFunc: notifyStart,
}
go tcp.ActivateAndServe()
for i := 0; i < 2; i++ {
select {
case <-up:
case <-time.After(5 * time.Second):
c.Fatal("timed out waiting for server to start")
}
}
return udpListener.(*net.UDPConn).LocalAddr().String(), tcpListener.Addr().String(), func() {
udp.Shutdown()
tcp.Shutdown()
}
}
func main() {
l := lever.New("struggledns", nil)
l.Add(lever.Param{
Name: "--listen-addr",
Description: "Address to listen on for dns requests. Will bind to both tcp and udp",
Default: ":53",
})
l.Add(lever.Param{
Name: "--fwd-to",
Description: "Address (ip:port) of a dns server to attempt forward requests to. Specify multiple times to make multiple request attempts. Order specified dictates precedence should more than one server respond for a request",
})
l.Add(lever.Param{
Name: "--parallel",
Description: "If sent the query will be sent to all addresses in parallel",
Flag: true,
})
l.Add(lever.Param{
Name: "--timeout",
Description: "Timeout in milliseconds for each request",
Default: "300",
})
l.Add(lever.Param{
Name: "--log-level",
Description: "Minimum log level to show, either debug, info, warn, error, or fatal",
Default: "warn",
})
l.Add(lever.Param{
Name: "--allow-truncated",
Description: "If we should allow truncated responses to be proxied",
Flag: true,
})
if version != "" {
l.Add(lever.Param{
Name: "--version",
Aliases: []string{"-v"},
Description: "Print version info",
Flag: true,
})
}
l.Parse()
if l.ParamFlag("--version") {
fmt.Println(version)
return
}
addr, _ := l.ParamStr("--listen-addr")
dnsServers, _ := l.ParamStrs("--fwd-to")
combineGroups := l.ParamFlag("--parallel")
timeout, _ := l.ParamInt("--timeout")
logLevel, _ := l.ParamStr("--log-level")
llog.SetLevelFromString(logLevel)
allowTruncated = l.ParamFlag("--allow-truncated")
if combineGroups {
//combine all the servers sent into one group
dnsServerGroups = make([][]string, 1)
var groupServers []string
for i := range dnsServers {
groupServers = strings.Split(dnsServers[i], ",")
dnsServerGroups[0] = append(dnsServerGroups[0], groupServers...)
}
} else {
dnsServerGroups = make([][]string, len(dnsServers))
for i := range dnsServers {
dnsServerGroups[i] = strings.Split(dnsServers[i], ",")
}
}
client = dns.Client{
//since this is UDP, the Dial/Write timeouts don't mean much
//we really only care about setting the read
DialTimeout: time.Millisecond * 100,
WriteTimeout: time.Millisecond * 100,
ReadTimeout: time.Millisecond * time.Duration(timeout),
UDPSize: 4096,
}
handler := dns.HandlerFunc(handleRequest)
go func() {
llog.Info("listening on udp", llog.KV{"addr": addr})
err := dns.ListenAndServe(addr, "udp", handler)
llog.Fatal("error listening on udp", llog.KV{"err": err})
}()
go func() {
llog.Info("listening on tcp", llog.KV{"addr": addr})
err := dns.ListenAndServe(addr, "tcp", handler)
llog.Fatal("error listening on tcp", llog.KV{"err": err})
}()
select {}
}
// TODO(alx): Settle on naming for handlers acting as middleware.
func protocolHandler(maxAnswers int, next dns.Handler) dns.Handler {
return dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
next.ServeDNS(&truncatingWriter{w, maxAnswers}, r)
})
}
func TestServerSimpleQuery(t *testing.T) {
var (
testRecord1 = Record{"test.weave.local.", net.ParseIP("10.20.20.10"), 0, 0, 0}
testRecord2 = Record{"test.weave.local.", net.ParseIP("10.20.20.20"), 0, 0, 0}
testInAddr1 = "10.20.20.10.in-addr.arpa."
)
InitDefaultLogging(testing.Verbose())
Info.Println("TestServerSimpleQuery starting")
mzone := newMockedZoneWithRecords([]ZoneRecord{testRecord1, testRecord2})
mdnsServer, err := NewMDNSServer(mzone, true, DefaultLocalTTL)
require.NoError(t, err)
err = mdnsServer.Start(nil)
require.NoError(t, err)
defer mdnsServer.Stop()
var receivedAddrs []net.IP
receivedName := ""
recvChan := make(chan interface{})
receivedCount := 0
// Implement a minimal listener for responses
multicast, err := LinkLocalMulticastListener(nil)
require.NoError(t, err)
handleMDNS := func(w dns.ResponseWriter, r *dns.Msg) {
// Only handle responses here
if len(r.Answer) > 0 {
t.Logf("Received %d answer(s)", len(r.Answer))
for _, answer := range r.Answer {
recvChan <- answer
}
recvChan <- "ok"
}
}
sendQuery := func(name string, querytype uint16) {
receivedAddrs = make([]net.IP, 0)
receivedName = ""
receivedCount = 0
m := new(dns.Msg)
m.SetQuestion(name, querytype)
m.RecursionDesired = false
buf, err := m.Pack()
require.NoError(t, err)
conn, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
require.NoError(t, err)
Debug.Printf("Sending UDP packet to %s", ipv4Addr)
_, err = conn.WriteTo(buf, ipv4Addr)
require.NoError(t, err)
Debug.Printf("Waiting for response")
for {
select {
case x := <-recvChan:
switch rr := x.(type) {
case *dns.A:
t.Logf("... A:\n%+v", rr)
receivedAddrs = append(receivedAddrs, rr.A)
receivedCount++
case *dns.PTR:
t.Logf("... PTR:\n%+v", rr)
receivedName = rr.Ptr
receivedCount++
case string:
return
}
case <-time.After(100 * time.Millisecond):
Debug.Printf("Timeout while waiting for response")
return
}
}
}
listener := &dns.Server{
Unsafe: true,
PacketConn: multicast,
Handler: dns.HandlerFunc(handleMDNS),
ReadTimeout: 100 * time.Millisecond}
go listener.ActivateAndServe()
defer listener.Shutdown()
time.Sleep(100 * time.Millisecond) // Allow for server to get going
Debug.Printf("Checking that we get 2 IPs fo name '%s' [A]", testRecord1.Name())
sendQuery(testRecord1.Name(), dns.TypeA)
if receivedCount != 2 {
t.Fatalf("Unexpected result count %d for %s", receivedCount, testRecord1.Name())
}
if !(receivedAddrs[0].Equal(testRecord1.IP()) || receivedAddrs[0].Equal(testRecord2.IP())) {
t.Fatalf("Unexpected result %s for %s", receivedAddrs, testRecord1.Name())
}
if !(receivedAddrs[1].Equal(testRecord1.IP()) || receivedAddrs[1].Equal(testRecord2.IP())) {
t.Fatalf("Unexpected result %s for %s", receivedAddrs, testRecord1.Name())
}
Debug.Printf("Checking that 'testfail.weave.' [A] gets no answers")
sendQuery("testfail.weave.", dns.TypeA)
if receivedCount != 0 {
t.Fatalf("Unexpected result count %d for testfail.weave", receivedCount)
}
Debug.Printf("Checking that '%s' [PTR] gets one name", testInAddr1)
sendQuery(testInAddr1, dns.TypePTR)
if receivedCount != 1 {
t.Fatalf("Expected an answer to %s, got %d answers", testInAddr1, receivedCount)
} else if !(testRecord1.Name() == receivedName) {
t.Fatalf("Expected answer %s to query for %s, got %s", testRecord1.Name(), testInAddr1, receivedName)
}
}
