protocol: add v2 wire protocol with binary framing and capability negotiation (#5294)

server/registry/registry.go

@@ -29,6 +29,7 @@ type ClientInfo struct {
 	Hostname         string
 	IP               string
 	Version          string
+	WireProtocol     string
 	FirstConnectedAt time.Time
 	LastConnectedAt  time.Time
 	DisconnectedAt   time.Time
@@ -51,7 +52,7 @@ func NewClientRegistry() *ClientRegistry {
 }
 
 // Register stores/updates metadata for a client and returns the registry key plus whether it conflicts with an online client.
-func (cr *ClientRegistry) Register(user, rawClientID, runID, hostname, version, remoteAddr string) (key string, conflict bool) {
+func (cr *ClientRegistry) Register(user, rawClientID, runID, hostname, version, remoteAddr, wireProtocol string) (key string, conflict bool) {
 	if runID == "" {
 		return "", false
 	}
@@ -88,6 +89,7 @@ func (cr *ClientRegistry) Register(user, rawClientID, runID, hostname, version,
 	info.Hostname = hostname
 	info.IP = remoteAddr
 	info.Version = version
+	info.WireProtocol = wireProtocol
 	if info.FirstConnectedAt.IsZero() {
 		info.FirstConnectedAt = now
 	}

server/registry/registry_test.go

@@ -0,0 +1,37 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package registry
+
+import (
+	"testing"
+
+	"github.com/fatedier/frp/pkg/proto/wire"
+)
+
+func TestClientRegistryRegisterStoresWireProtocol(t *testing.T) {
+	registry := NewClientRegistry()
+	key, conflict := registry.Register("user", "client-id", "run-id", "host", "1.0.0", "127.0.0.1", wire.ProtocolV2)
+	if conflict {
+		t.Fatal("unexpected client conflict")
+	}
+
+	info, ok := registry.GetByKey(key)
+	if !ok {
+		t.Fatalf("client %q not found", key)
+	}
+	if info.WireProtocol != wire.ProtocolV2 {
+		t.Fatalf("wire protocol mismatch, want %q got %q", wire.ProtocolV2, info.WireProtocol)
+	}
+}