feat: Waku v2 bridge

Issue #12610

vendor/github.com/pion/dtls/v2/flight5bhandler.go

@@ -0,0 +1,75 @@
+package dtls
+
+import (
+	"context"
+
+	"github.com/pion/dtls/v2/pkg/crypto/prf"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight5bParse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	_, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence-1,
+		handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, false, false},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+
+	if _, ok = msgs[handshake.TypeFinished].(*handshake.MessageFinished); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	// Other party may re-transmit the last flight. Keep state to be flight5b.
+	return flight5b, nil, nil
+}
+
+func flight5bGenerate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) { //nolint:gocognit
+	var pkts []*packet
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &protocol.ChangeCipherSpec{},
+			},
+		})
+
+	if len(state.localVerifyData) == 0 {
+		plainText := cache.pullAndMerge(
+			handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, false, false},
+		)
+
+		var err error
+		state.localVerifyData, err = prf.VerifyDataClient(state.masterSecret, plainText, state.cipherSuite.HashFunc())
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+	}
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+					Epoch:   1,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageFinished{
+						VerifyData: state.localVerifyData,
+					},
+				},
+			},
+			shouldEncrypt:            true,
+			resetLocalSequenceNumber: true,
+		})
+
+	return pkts, nil, nil
+}