#!/bin/bash
# 设置 bridge 名称
BRIDGE=dragonos-bridge
# 设置网络信息
NETWORK=192.168.137.0
NETMASK=255.255.255.0
GATEWAY=192.168.137.1
DHCPRANGE=192.168.137.100,192.168.137.200
# 启用PXE支持的可选参数
TFTPROOT=
BOOTP=

function check_bridge()
{
        if brctl show | grep "^$BRIDGE" &> /dev/null; then
                return 1
        else
                return 0
        fi
}

function create_bridge()
{
        brctl addbr "$BRIDGE"
        brctl stp "$BRIDGE" on
        brctl setfd "$BRIDGE" 0
        ifconfig "$BRIDGE" "$GATEWAY" netmask "$NETMASK" up
}

function enable_ip_forward()
{
        echo 1 > /proc/sys/net/ipv4/ip_forward
}

function add_filter_rules()
{
        iptables -t nat -A POSTROUTING -s "$NETWORK"/"$NETMASK" \
                ! -d "$NETWORK"/"$NETMASK" -j MASQUERADE
}

function start_dnsmasq()
{
# 禁止重复运行dnsmasq
        ps -ef | grep "dnsmasq" | grep -v "grep" &> /dev/null
        if [ $? -eq 0 ]; then
                echo "dnsmasq 已经在运行"
                return 1
        fi
        dnsmasq \
                --strict-order \
                --except-interface=lo \
                --interface=$BRIDGE \
                --listen-address=$GATEWAY \
                --bind-interfaces \
                --dhcp-range=$DHCPRANGE \
                --conf-file="" \
                --pid-file=/var/run/qemu-dhcp-$BRIDGE.pid \
                --dhcp-leasefile=/var/run/qemu-dhcp-$BRIDGE.leases \
                --dhcp-no-override \
                ${TFTPROOT:+"--enable-tftp"} \
                ${TFTPROOT:+"--tftp-root=$TFTPROOT"} \
                ${BOOTP:+"--dhcp-boot=$BOOTP"}
}

function setup_bridge_nat()
{
        check_bridge "$BRIDGE"
        if [ $? -eq 0 ]; then
                create_bridge
        fi
        enable_ip_forward
        add_filter_rules "$BRIDGE"
        start_dnsmasq "$BRIDGE"
}

# 安装前需要检查$1参数
if [ -n "$1" ]; then
        setup_bridge_nat
        brctl addif "$BRIDGE" "$1"
        ifconfig "$1" 0.0.0.0 up
        exit 0
else
        echo "发现错误：没有指定接口"
        exit 1
fi