feat(vpn): replace buggy custom TCP/UDP bridge with robust gVisor-based FakeDNS proxy via tun2socks interceptor

Author: Hidden-Node

mobile/mobile.go

@@ -148,19 +148,34 @@ func GetListenAddress() string {
 	return ""
 }
 
-// StartTunBridge starts the TUN bridge with DNS interception.
+// StartTunBridge starts the TUN bridge with DNS interception using FakeDNS proxy.
 func StartTunBridge(tunFd int64, mtu int64, socksAddr string) error {
-	return tun.StartTunBridge(int32(tunFd), int32(mtu), socksAddr)
+	proxyAddr, err := tun.StartFakeDNSProxy(socksAddr)
+	if err != nil {
+		return err
+	}
+	
+	key := &engine.Key{
+		Proxy:  "socks5://" + proxyAddr,
+		Device: fmt.Sprintf("fd://%d", tunFd),
+		MTU:    int(mtu),
+	}
+
+	engine.Insert(key)
+	engine.Start()
+	
+	return nil
 }
 
 // StopTunBridge stops the DNS-aware TUN bridge.
 func StopTunBridge() {
-	tun.StopTunBridge()
+	engine.Stop()
+	tun.StopFakeDNSProxy()
 }
 
 // IsTunBridgeRunning returns true if the DNS-aware TUN bridge is active.
 func IsTunBridgeRunning() bool {
-	return tun.IsTunBridgeRunning()
+	return tun.IsFakeDNSProxyRunning()
 }
 
 // GetTunBandwidth returns upload/download counters from the TUN bridge.

mobile/tun/dns_mapper.go

@@ -0,0 +1,55 @@
+package tun
+
+import (
+	"fmt"
+	"log"
+	"sync"
+	"sync/atomic"
+)
+
+type DNSMapper struct {
+	mu           sync.RWMutex
+	hostnameToIP map[string]string
+	ipToHostname map[string]string
+	counter      uint32
+}
+
+func NewDNSMapper() *DNSMapper {
+	return &DNSMapper{
+		hostnameToIP: make(map[string]string),
+		ipToHostname: make(map[string]string),
+		counter:      1,
+	}
+}
+
+func (d *DNSMapper) GetFakeIP(hostname string) string {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	if ip, ok := d.hostnameToIP[hostname]; ok {
+		return ip
+	}
+
+	counter := atomic.AddUint32(&d.counter, 1)
+	if counter > 65535 {
+		atomic.StoreUint32(&d.counter, 1)
+		counter = 1
+	}
+
+	octet3 := byte(counter >> 8)
+	octet4 := byte(counter & 0xFF)
+	fakeIP := fmt.Sprintf("198.18.%d.%d", octet3, octet4)
+
+	d.hostnameToIP[hostname] = fakeIP
+	d.ipToHostname[fakeIP] = hostname
+
+	log.Printf("[TUN-DNS] Mapped %s -> %s", hostname, fakeIP)
+	return fakeIP
+}
+
+func (d *DNSMapper) GetHostname(fakeIP string) (string, bool) {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	hostname, ok := d.ipToHostname[fakeIP]
+	return hostname, ok
+}