From e0d715a5936e3c098262afae5af9eb6dc025e4ad Mon Sep 17 00:00:00 2001
From: chick <chick@chickdeiMac.local>
Date: Tue, 2 Jun 2026 23:10:58 +0800
Subject: [PATCH] feat: add virtual subnet forwarding rules

---
 README.md  | 21 ++++++++++++++++++++-
 install.sh | 20 +++++++++++++++++++-
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index a21118e..3886b35 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,9 @@
 
 - 开启 IPv4 转发：`/proc/sys/net/ipv4/ip_forward = 1`
 - 允许 `192.168.2.0/24` 与 `192.168.3.0/24` 双向转发
+- 允许 `192.168.2.0/24`、`192.168.3.0/24` 主动访问虚拟组网 `192.168.4.0/24`
+- 允许 `192.168.4.0/24` 到 `192.168.2.0/24`、`192.168.3.0/24` 的 RELATED/ESTABLISHED 回包
+- 禁止 `192.168.4.0/24` 主动访问 `192.168.2.0/24`、`192.168.3.0/24`，实现安全隔离
 - 允许 `tun0` 入站/出站 FORWARD
 - 开机延迟 `20s` 执行
 
@@ -25,7 +28,7 @@ curl -fsSL https://gitea.chickliu.fun/Hermes/fnos-iptables-forward/raw/branch/ma
 ## 自定义网段 / 网卡 / 延迟
 
 ```bash
-sudo LAN_A=192.168.2.0/24 LAN_B=192.168.3.0/24 TUN_IF=tun0 DELAY=20s bash install.sh install
+sudo LAN_A=192.168.2.0/24 LAN_B=192.168.3.0/24 VIRTUAL_LAN=192.168.4.0/24 TUN_IF=tun0 DELAY=20s bash install.sh install
 ```
 
 ## 查看状态
@@ -66,8 +69,24 @@ set -Eeuo pipefail
 echo 1 > /proc/sys/net/ipv4/ip_forward
 iptables -F FORWARD
 iptables -P FORWARD ACCEPT
+
+# 放行 192.168.3.0/24 <-> 192.168.2.0/24
 iptables -A FORWARD -s 192.168.2.0/24 -d 192.168.3.0/24 -j ACCEPT
 iptables -A FORWARD -s 192.168.3.0/24 -d 192.168.2.0/24 -j ACCEPT
+
+# 放行 192.168.3.0/24、192.168.2.0/24 -> 192.168.4.0/24（虚拟组网）
+iptables -A FORWARD -s 192.168.3.0/24 -d 192.168.4.0/24 -j ACCEPT
+iptables -A FORWARD -s 192.168.2.0/24 -d 192.168.4.0/24 -j ACCEPT
+
+# 放行 192.168.4.0/24 -> 192.168.3.0/24、192.168.2.0/24 的回包（必须）
+iptables -A FORWARD -s 192.168.4.0/24 -d 192.168.3.0/24 -m state --state RELATED,ESTABLISHED -j ACCEPT
+iptables -A FORWARD -s 192.168.4.0/24 -d 192.168.2.0/24 -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+# 禁止 192.168.4.0/24 主动访问 192.168.3.0/24、192.168.2.0/24（安全隔离）
+iptables -A FORWARD -s 192.168.4.0/24 -d 192.168.3.0/24 -j DROP
+iptables -A FORWARD -s 192.168.4.0/24 -d 192.168.2.0/24 -j DROP
+
+# 放行 EasyTier 虚拟网卡 tun0
 iptables -A FORWARD -i tun0 -j ACCEPT
 iptables -A FORWARD -o tun0 -j ACCEPT
 ```
diff --git a/install.sh b/install.sh
index 0338de8..d1e424a 100755
--- a/install.sh
+++ b/install.sh
@@ -9,6 +9,7 @@ TIMER_FILE="${TIMER_FILE:-/etc/systemd/system/${SERVICE_NAME}.timer}"
 DELAY="${DELAY:-20s}"
 LAN_A="${LAN_A:-192.168.2.0/24}"
 LAN_B="${LAN_B:-192.168.3.0/24}"
+VIRTUAL_LAN="${VIRTUAL_LAN:-192.168.4.0/24}"
 TUN_IF="${TUN_IF:-tun0}"
 MODE="${1:-install}"
 
@@ -28,8 +29,24 @@ echo 1 > /proc/sys/net/ipv4/ip_forward
 
 iptables -F FORWARD
 iptables -P FORWARD ACCEPT
+
+# 放行 ${LAN_B} <-> ${LAN_A}
 iptables -A FORWARD -s ${LAN_A} -d ${LAN_B} -j ACCEPT
 iptables -A FORWARD -s ${LAN_B} -d ${LAN_A} -j ACCEPT
+
+# 放行 ${LAN_B}/${LAN_A} -> ${VIRTUAL_LAN}（虚拟组网）
+iptables -A FORWARD -s ${LAN_B} -d ${VIRTUAL_LAN} -j ACCEPT
+iptables -A FORWARD -s ${LAN_A} -d ${VIRTUAL_LAN} -j ACCEPT
+
+# 放行 ${VIRTUAL_LAN} -> ${LAN_B}/${LAN_A} 的回包（必须）
+iptables -A FORWARD -s ${VIRTUAL_LAN} -d ${LAN_B} -m state --state RELATED,ESTABLISHED -j ACCEPT
+iptables -A FORWARD -s ${VIRTUAL_LAN} -d ${LAN_A} -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+# 禁止 ${VIRTUAL_LAN} 主动访问 ${LAN_B}/${LAN_A}（安全隔离）
+iptables -A FORWARD -s ${VIRTUAL_LAN} -d ${LAN_B} -j DROP
+iptables -A FORWARD -s ${VIRTUAL_LAN} -d ${LAN_A} -j DROP
+
+# 放行 EasyTier 虚拟网卡 ${TUN_IF}
 iptables -A FORWARD -i ${TUN_IF} -j ACCEPT
 iptables -A FORWARD -o ${TUN_IF} -j ACCEPT
 EOF
@@ -113,6 +130,7 @@ Usage: sudo bash install.sh [install|status|uninstall]
 Environment overrides:
   LAN_A=$LAN_A
   LAN_B=$LAN_B
+  VIRTUAL_LAN=$VIRTUAL_LAN
   TUN_IF=$TUN_IF
   DELAY=$DELAY
   SERVICE_NAME=$SERVICE_NAME
@@ -120,7 +138,7 @@ Environment overrides:
 
 Examples:
   sudo bash install.sh install
-  sudo LAN_A=192.168.2.0/24 LAN_B=192.168.3.0/24 TUN_IF=tun0 bash install.sh install
+  sudo LAN_A=192.168.2.0/24 LAN_B=192.168.3.0/24 VIRTUAL_LAN=192.168.4.0/24 TUN_IF=tun0 bash install.sh install
   sudo DELAY=30s bash install.sh install
   sudo bash install.sh status
   sudo bash install.sh uninstall