Add support for DTLS 1.2 Connection IDs #473
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,77 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
| "log" | ||
| "net" | ||
|
|
||
| piondtls "github.com/pion/dtls/v2" | ||
| "github.com/plgd-dev/go-coap/v3/dtls" | ||
| ) | ||
|
|
||
| func main() { | ||
| conf := &piondtls.Config{ | ||
| PSK: func(hint []byte) ([]byte, error) { | ||
| fmt.Printf("Server's hint: %s \n", hint) | ||
| return []byte{0xAB, 0xC1, 0x23}, nil | ||
| }, | ||
| PSKIdentityHint: []byte("Pion DTLS Client"), | ||
| CipherSuites: []piondtls.CipherSuiteID{piondtls.TLS_PSK_WITH_AES_128_CCM_8}, | ||
| ConnectionIDGenerator: piondtls.OnlySendCIDGenerator(), | ||
| } | ||
| raddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:5688") | ||
| if err != nil { | ||
| log.Fatalf("Error resolving UDP address: %v", err) | ||
| } | ||
|
|
||
| // Setup first UDP listener. | ||
| udpconn, err := net.ListenUDP("udp", nil) | ||
| if err != nil { | ||
| log.Fatalf("Error establishing UDP listener: %v", err) | ||
| } | ||
|
|
||
| // Create DTLS client on UDP listener. | ||
| client, err := piondtls.Client(udpconn, raddr, conf) | ||
| if err != nil { | ||
| log.Fatalf("Error establishing DTLS client: %v", err) | ||
| } | ||
| co := dtls.Client(client) | ||
| resp, err := co.Get(context.Background(), "/a") | ||
| if err != nil { | ||
| log.Fatalf("Error performing request: %v", err) | ||
| } | ||
| log.Printf("Response payload: %+v", resp) | ||
| resp, err = co.Get(context.Background(), "/b") | ||
| if err != nil { | ||
| log.Fatalf("Error performing request: %v", err) | ||
| } | ||
| log.Printf("Response payload: %+v", resp) | ||
|
|
||
| // Export state to resume connection from another address. | ||
| state := client.ConnectionState() | ||
|
|
||
| // Setup second UDP listener on a different address. | ||
| udpconn, err = net.ListenUDP("udp", nil) | ||
| if err != nil { | ||
| log.Fatalf("Error establishing UDP listener: %v", err) | ||
| } | ||
|
|
||
| // Resume connection on new address with previous state. | ||
| client, err = piondtls.Resume(&state, udpconn, raddr, conf) | ||
| if err != nil { | ||
| log.Fatalf("Error resuming DTLS connection: %v", err) | ||
| } | ||
| co = dtls.Client(client) | ||
| // Requests can be performed without performing a second handshake. | ||
| resp, err = co.Get(context.Background(), "/a") | ||
| if err != nil { | ||
| log.Fatalf("Error performing request: %v", err) | ||
| } | ||
| log.Printf("Response payload: %+v", resp) | ||
| resp, err = co.Get(context.Background(), "/b") | ||
| if err != nil { | ||
| log.Fatalf("Error performing request: %v", err) | ||
| } | ||
| log.Printf("Response payload: %+v", resp) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,92 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "context" | ||
| "fmt" | ||
| "log" | ||
| "net" | ||
| "sync/atomic" | ||
| "time" | ||
|
|
||
| piondtls "github.com/pion/dtls/v2" | ||
| "github.com/plgd-dev/go-coap/v3/dtls/server" | ||
| "github.com/plgd-dev/go-coap/v3/message" | ||
| "github.com/plgd-dev/go-coap/v3/message/codes" | ||
| "github.com/plgd-dev/go-coap/v3/mux" | ||
| "github.com/plgd-dev/go-coap/v3/options" | ||
| udpClient "github.com/plgd-dev/go-coap/v3/udp/client" | ||
| ) | ||
|
|
||
| func handleA(w mux.ResponseWriter, r *mux.Message) { | ||
| log.Printf("got message in handleA: %+v from %v\n", r, w.Conn().RemoteAddr()) | ||
| err := w.SetResponse(codes.GET, message.TextPlain, bytes.NewReader([]byte("A hello world"))) | ||
| if err != nil { | ||
| log.Printf("cannot set response: %v", err) | ||
| } | ||
| } | ||
|
|
||
| func handleB(w mux.ResponseWriter, r *mux.Message) { | ||
| log.Printf("got message in handleB: %+v from %v\n", r, w.Conn().RemoteAddr()) | ||
| customResp := w.Conn().AcquireMessage(r.Context()) | ||
| defer w.Conn().ReleaseMessage(customResp) | ||
| customResp.SetCode(codes.Content) | ||
| customResp.SetToken(r.Token()) | ||
| customResp.SetContentFormat(message.TextPlain) | ||
| customResp.SetBody(bytes.NewReader([]byte("B hello world"))) | ||
| err := w.Conn().WriteMessage(customResp) | ||
| if err != nil { | ||
| log.Printf("cannot set response: %v", err) | ||
| } | ||
| } | ||
|
|
||
| // wrappedListener wraps a net.Listener and implements a go-coap DTLS | ||
| // server.Listener. | ||
| // NOTE: this utility is for example purposes only. Context should be handled | ||
| // properly in meaningful scenarios. | ||
| type wrappedListener struct { | ||
| l net.Listener | ||
| closed atomic.Bool | ||
| } | ||
|
|
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| // AcceptWithContext disregards the passed context and calls the underlying | ||
| // net.Listener Accept(). | ||
| func (w *wrappedListener) AcceptWithContext(_ context.Context) (net.Conn, error) { | ||
| return w.l.Accept() | ||
| } | ||
|
|
||
| // Close calls the underlying net.Listener Close(). | ||
| func (w *wrappedListener) Close() error { | ||
| return w.l.Close() | ||
| } | ||
|
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| // wrapListener wraps a net.Listener and returns a DTLS server.Listener. | ||
| func wrapListener(l net.Listener) server.Listener { | ||
| return &wrappedListener{ | ||
| l: l, | ||
| } | ||
| } | ||
|
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| func main() { | ||
| m := mux.NewRouter() | ||
| m.Handle("/a", mux.HandlerFunc(handleA)) | ||
| m.Handle("/b", mux.HandlerFunc(handleB)) | ||
| laddr, err := net.ResolveUDPAddr("udp", "127.0.0.1:5688") | ||
| if err != nil { | ||
| log.Fatalf("Error dialing: %v", err) | ||
| } | ||
| l, err := piondtls.Listen("udp", laddr, &piondtls.Config{ | ||
| PSK: func(hint []byte) ([]byte, error) { | ||
| fmt.Printf("Client's hint: %s \n", hint) | ||
| return []byte{0xAB, 0xC1, 0x23}, nil | ||
| }, | ||
| PSKIdentityHint: []byte("Pion DTLS Server"), | ||
| CipherSuites: []piondtls.CipherSuiteID{piondtls.TLS_PSK_WITH_AES_128_CCM_8}, | ||
| ConnectionIDGenerator: piondtls.RandomCIDGenerator(8), | ||
| }) | ||
| if err != nil { | ||
| log.Fatalf("Error establishing DTLS listener: %v", err) | ||
| } | ||
| s := server.New(options.WithMux(m), options.WithInactivityMonitor(10*time.Second, func(cc *udpClient.Conn) {})) | ||
| s.Serve(wrapListener(l)) | ||
| } | ||
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@jkralik I'm not sure if there is appetite to do so, but I would be interested in
go-coapdefining a commonContextListenerand utility wrappers to allow for the passing ofnet.Listener. For now, consumers of this functionality will need to use a custom listener as demonstrated in this example.There was a problem hiding this comment.
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Yes, I see the point. But one thing - Has handshaking been moved to
Conn.Read/Writefromlistener.Accept? If not, we need to incorporate it with https://github.com/plgd-dev/go-coap/blob/master/net/dtlslistener.go#L37.There was a problem hiding this comment.
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@jkralik I'm not sure I'm following your suggestion here. Handshaking has not moved -- from the perspective of the existing
DTLSListenernothing has changed. In fact, setting theconnectionIDGeneratoron thepion/dtlsconfig passed toNewDTLSListenerwould enable connection ID support. The issue is that the underlyingpion/transport/udppackage being used does not support routing based on Connection ID. A replacement has been introduced in https://github.com/pion/dtls/tree/master/internal/net/udp, which is ininternalfor now so that it can be iterated upon prior to folks taking a direct dependency on its API. It can be consumed by using thepion/dtls.Listenfunction.I do think it would be good for the functionality to become the default in
go-coap, but right now theDTLSListeneris restrictive about the behavior it allows (anecdotally, we use a different implementation of theDTLSListenerinternally so introduce additional functionality). This PR maintains the existinggo-coapfunctionality, while also demonstrating how a consumer can provide their own listener for custom functionality (including connection IDs).It seems like previously the
pion/dtls.Listenerwas used, but then was moved away from in order to introduce parallel handshakes. My understanding of this functionality is that theDTLSListeneressentially just continuously accepts connections so that the handshake can begin and complete, perhaps before the DTLSServercallsAcceptWithContext(). It seems the major blocker from using thepion/dtls.Listeneris the [starting of thepion/dtls.Serverin a go pool. My question is whether this could be functionality introduced inpion/dtlsinstead (i.e. stop blockingAccept()on completion of the handshake), which would allowgo-coapto treat the DTLS listener as just anet.Listener(with the generic wrapping to support context handling).There was a problem hiding this comment.
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(Note: this is what I would like to do long term, but the changes in this PR enable folks to implement custom behavior to enable connection ID support, while keeping the previous behavior of
go-coapunchanged when using the providedDTLSListenerimplementation. This feels like a good intermediate step to me as it does not introduce any breaking changes ingo-coap, but I am open to discussion and happy to explore other avenues as well!)There was a problem hiding this comment.
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There is a discussion (pion/dtls#279) about moving the handshake, as it is in the
golang/cryptopackage, to theRead/Writefunctions.I agree with you; we can proceed step by step.