feat(vxlan-overlay-hub): added and modified Ansible roles

- Added new role 'vxlan-overlay-hub' to ansible playbooks
- Renamed vpn-overlay.yaml playbook to vpn-overlay-vxlan-site.yaml
- Modified sit/vpn-overlay configuration according to the new setup

ansible/playbooks/roles/vhosts/vpn-overlay/vxlan/hub/defaults/main.yml

@@ -0,0 +1,7 @@
+---
+# Default VXLAN settings for site nodes
+vxlan_dev_if: wg0
+vxlan_vni: 100
+vxlan_cidr_suffix: 16
+overlay_config_path: config/sit/vpn-overlay.yaml
+

ansible/playbooks/roles/vhosts/vpn-overlay/vxlan/hub/files/setup_sit_vxlan.sh

@@ -0,0 +1,83 @@
+#!/bin/bash
+# 安全增强版 VXLAN Overlay 脚本（支持 wg0 作为通道设备 + 可选公网 DNAT 映射）
+# 用法： ./setup_sit_vxlan.sh <dev_if> <local_ip> <remote_ip> <br0_ip> [cidr_suffix] [vxlan_id] [mtu] [expose_port]
+
+set -e
+
+DEV_IF="$1"
+LOCAL_IP="$2"
+REMOTE_IP="$3"
+BRIDGE_IP="$4"
+CIDR_SUFFIX="${5:-16}"
+VNI="${6:-100}"
+MTU="${7:-1400}"
+EXPOSE_PORT="${8:-443}"
+
+if [[ -z "$DEV_IF" || -z "$LOCAL_IP" || -z "$REMOTE_IP" || -z "$BRIDGE_IP" ]]; then
+  echo "Usage: $0 <dev_if> <local_ip> <remote_ip> <br0_ip> [cidr_suffix] [vxlan_id] [mtu] [expose_port]"
+  exit 1
+fi
+
+VXLAN_IF="vxlan${VNI}"
+BR_IF="br0"
+BRIDGE_CIDR="${BRIDGE_IP}/${CIDR_SUFFIX}"
+SUBNET="$(echo "$BRIDGE_IP" | cut -d. -f1-2).0.0/${CIDR_SUFFIX}"
+
+# 自动判断 dev 是否能用于 VXLAN（需支持广播）
+function is_vxlan_dev_usable() {
+  [[ -d "/sys/class/net/$1" ]] && grep -q "broadcast" "/sys/class/net/$1/flags"
+}
+
+echo "🔍 检查 $DEV_IF 是否可用于 VXLAN..."
+USE_DEV_PARAM=true
+if ! is_vxlan_dev_usable "$DEV_IF"; then
+  echo "⚠️  $DEV_IF 不支持广播，将省略 dev 参数（通过路由走隧道）"
+  USE_DEV_PARAM=false
+fi
+
+# 清理旧接口
+for iface in "$VXLAN_IF" "$BR_IF"; do
+  ip link show "$iface" &>/dev/null && ip link set "$iface" down && ip link del "$iface"
+done
+
+# 创建 VXLAN 接口
+echo "🛠️ 创建 VXLAN 接口 $VXLAN_IF ..."
+if $USE_DEV_PARAM; then
+  ip link add "$VXLAN_IF" type vxlan id "$VNI" dstport 4789 local "$LOCAL_IP" remote "$REMOTE_IP" dev "$DEV_IF"
+else
+  ip link add "$VXLAN_IF" type vxlan id "$VNI" dstport 4789 local "$LOCAL_IP" remote "$REMOTE_IP"
+fi
+ip link set "$VXLAN_IF" mtu "$MTU"
+ip link set "$VXLAN_IF" up
+
+# 创建 br0 桥
+ip link add "$BR_IF" type bridge
+ip link set "$BR_IF" mtu "$MTU"
+ip link set "$VXLAN_IF" master "$BR_IF"
+ip link set "$BR_IF" up
+
+# 配置 IP
+ip addr add "$BRIDGE_CIDR" dev "$BR_IF"
+
+# 启用转发 + SNAT（仅主机出网时）
+sysctl -w net.ipv4.ip_forward=1
+iptables -t nat -C POSTROUTING -s "$SUBNET" -o "$DEV_IF" -j MASQUERADE 2>/dev/null || \
+iptables -t nat -A POSTROUTING -s "$SUBNET" -o "$DEV_IF" -j MASQUERADE
+
+# ⚠️ 可选：仅在 EXPOSE_PORT 被定义时启用 DNAT 公网端口映射
+if [[ -n "$EXPOSE_PORT" ]]; then
+  echo "🌐 添加 DNAT 映射规则：公网:$EXPOSE_PORT → ${BRIDGE_IP}:443"
+
+  iptables -t nat -C PREROUTING -p tcp -m tcp --dport "$EXPOSE_PORT" -j DNAT --to-destination "${BRIDGE_IP}:443" 2>/dev/null || \
+  iptables -t nat -A PREROUTING -p tcp -m tcp --dport "$EXPOSE_PORT" -j DNAT --to-destination "${BRIDGE_IP}:443"
+fi
+
+# 展示结果
+echo ""
+echo "✅ VXLAN Overlay 已建立"
+echo "  - bridge: $BR_IF ($BRIDGE_CIDR)"
+echo "  - vxlan: $VXLAN_IF ($LOCAL_IP ⇄ $REMOTE_IP, id=$VNI, mtu=$MTU)"
+echo "  - SNAT: $SUBNET → $DEV_IF"
+if [[ -n "$EXPOSE_PORT" ]]; then
+echo "  - DNAT: 公网:$EXPOSE_PORT → ${BRIDGE_IP}:443"
+fi

ansible/playbooks/roles/vhosts/vpn-overlay/vxlan/hub/tasks/main.yml

@@ -0,0 +1,50 @@
+---
+- name: Load site overlay config
+  set_fact:
+    overlay_data: "{{ lookup('file', overlay_config_path) | from_yaml }}"
+
+- name: Select current site from config
+  set_fact:
+    current_hub: "{{ overlay_data.hubs | selectattr('name', 'equalto', inventory_hostname) | list | first }}"
+
+- name: Fail if no matching site found
+  fail:
+    msg: "当前主机 {{ inventory_hostname }} 未在 config 中定义"
+  when: current_hub is not defined
+
+- name: Set VXLAN parameters
+  set_fact:
+    vxlan_dev_if: "{{ current_hub.interface}}"
+    vxlan_local_ip: "{{ current_hub.local_ip }}"
+    vxlan_remote_ip: "{{ current_hub.remote_ip }}"
+    vxlan_br_ip: "{{ current_hub.br_ip }}"
+    vxlan_cidr_suffix: "{{ overlay_data.vxlan_cidr_suffix | default(16) }}"
+    vxlan_vni: "{{ overlay_data.vxlan_id | default(100) }}"
+
+- name: 使用 rsync 分发 VXLAN 脚本
+  synchronize:
+    src: "files/setup_sit_vxlan.sh"
+    dest: /tmp/setup_sit_vxlan.sh
+    mode: push
+
+- name: 移动脚本并赋权到 /usr/local/bin
+  shell: |
+    mv /tmp/setup_sit_vxlan.sh /usr/local/bin/setup_sit_vxlan.sh
+    chmod +x /usr/local/bin/setup_sit_vxlan.sh
+  become: true
+
+- name: Render systemd unit for VXLAN
+  template:
+    src: vxlan-setup.service.j2
+    dest: /etc/systemd/system/vxlan-setup.service
+    mode: '0644'
+
+- name: Reload systemd daemon
+  systemd:
+    daemon_reload: true
+
+- name: Enable and start VXLAN overlay setup
+  systemd:
+    name: vxlan-setup
+    enabled: true
+    state: started

ansible/playbooks/roles/vhosts/vpn-overlay/vxlan/hub/templates/vxlan-setup.service.j2

@@ -0,0 +1,12 @@
+[Unit]
+Description=VXLAN Overlay Setup for {{ inventory_hostname }}
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/bin/setup_sit_vxlan.sh {{ vxlan_dev_if }} {{ vxlan_local_ip }} {{ vxlan_remote_ip }} {{ vxlan_br_ip }} {{ vxlan_cidr_suffix }} {{ vxlan_vni }}
+RemainAfterExit=true
+
+[Install]
+WantedBy=multi-user.target

ansible/playbooks/vpn-overlay-vxlan-hub.yaml

@@ -0,0 +1,8 @@
+- name: Run infrastructure setup
+  hosts: all
+  become: yes
+  gather_facts: yes
+  vars:
+    overlay_config_path: "{{ playbook_dir }}/../../config/sit/vpn-overlay.yaml" 
+  roles:
+    - vhosts/vpn-overlay/vxlan/hub

config/sit/vpn-overlay.yaml

@@ -19,7 +19,7 @@ hubs:
     wg_ip: 172.30.0.1
     br_ip: 10.253.253.1
     local_ip: 172.30.0.1
-    remote_ip: 172.31.0.1
+    remote_ip: 172.31.0.10
     xray:
       uuid: "18d270a9-533d-4b13-b3f1-e7f55540a9b2"
       relay_address: "global-proxy.onwalk.net"