fix: detect and auto-configure rp_filter to loose mode (2) to prevent policy routing packet loss

install.sh

@@ -1020,6 +1020,36 @@ with open('$AUTH_FILE', 'w', encoding='utf-8') as f:
 fi
 
 # 8. Start service
+# 8.5 Optimize network parameters (rp_filter for policy routing)
+echo -e "\n正在优化网络参数 (配置反向路径过滤 rp_filter=2 以支持策略路由)..."
+if [ -d "/etc/sysctl.d" ]; then
+    cat > /etc/sysctl.d/99-aimilivpn.conf <<EOF
+net.ipv4.conf.all.rp_filter = 2
+net.ipv4.conf.default.rp_filter = 2
+EOF
+    sysctl -p /etc/sysctl.d/99-aimilivpn.conf >/dev/null 2>&1 || true
+else
+    # Fallback to appending to /etc/sysctl.conf
+    if ! grep -q "net.ipv4.conf.all.rp_filter" /etc/sysctl.conf; then
+        echo "" >> /etc/sysctl.conf
+        echo "net.ipv4.conf.all.rp_filter = 2" >> /etc/sysctl.conf
+        echo "net.ipv4.conf.default.rp_filter = 2" >> /etc/sysctl.conf
+    else
+        sed -i 's/net.ipv4.conf.all.rp_filter\s*=\s*[0-9]/net.ipv4.conf.all.rp_filter = 2/g' /etc/sysctl.conf
+        sed -i 's/net.ipv4.conf.default.rp_filter\s*=\s*[0-9]/net.ipv4.conf.default.rp_filter = 2/g' /etc/sysctl.conf
+    fi
+    sysctl -p >/dev/null 2>&1 || true
+fi
+# Apply to currently active interfaces dynamically
+sysctl -w net.ipv4.conf.all.rp_filter=2 >/dev/null 2>&1 || true
+sysctl -w net.ipv4.conf.default.rp_filter=2 >/dev/null 2>&1 || true
+if [ -d "/proc/sys/net/ipv4/conf" ]; then
+    for dev_dir in /proc/sys/net/ipv4/conf/*; do
+        dev_name=$(basename "$dev_dir")
+        sysctl -w net.ipv4.conf.${dev_name}.rp_filter=2 >/dev/null 2>&1 || true
+    done
+fi
+
 echo -e "\n正在启动 AimiliVPN 服务并初始化网络..."
 if command -v systemctl >/dev/null 2>&1; then
     systemctl restart aimilivpn.service || true

vpn_utils.py

@@ -611,4 +611,14 @@ def diagnose_local_obstructions(proxy_port: int = 7928, host: str = "127.0.0.1")
         except Exception:
             pass
 
+        # 4. 检查系统反向路径过滤 (rp_filter) 设置
+        rp_all_path = Path("/proc/sys/net/ipv4/conf/all/rp_filter")
+        if rp_all_path.exists():
+            try:
+                val = rp_all_path.read_text(encoding="utf-8").strip()
+                if val == "1":
+                    return 3008, "[ERR_ROUTE_RP_FILTER_STRICT] 系统启用了严格的反向路径过滤(rp_filter=1)。原因: 在启用策略路由时，严格的路径过滤会导致通过虚拟网卡 tun0 的回包被内核静默丢弃，导致连接超时。请将 net.ipv4.conf.all.rp_filter 设置为 2 或 0。"
+            except Exception:
+                pass
+
     return None␍

vpngate_manager.py

@@ -598,6 +598,12 @@ def setup_policy_routing(interface: str = "tun0") -> None:
         try:
             subprocess.run(["ip", "route", "add", "default", "dev", interface, "table", "100"], check=True, timeout=2)
             subprocess.run(["ip", "rule", "add", "oif", interface, "table", "100"], check=True, timeout=2)
+            # 配置反向路径过滤 rp_filter 为 loose 模式 (2)，防止回包被内核静默丢弃
+            for proc_path in ["all", "default", interface]:
+                try:
+                    subprocess.run(["sysctl", "-w", f"net.ipv4.conf.{proc_path}.rp_filter=2"], capture_output=True, timeout=2)
+                except Exception:
+                    pass
             print(f"[policy_routing] Enabled policy routing for interface {interface} (attempt {attempt} success)", flush=True)
             success = True
             break