openwrt的默认/etc/config/network文件是如何生成的？

openwrt的network文件，或者说在/etc/config下的文件，都是动态生成的。

脚本的函数定义在openwrt1407/package/base-files/files/lib/functions中，有以下几个文件：

tf@ubuntu:~/projects/openwrt1407/package/base-files/files/lib/functions$ ls
leds.sh  network.sh  preinit.sh  service.sh  system.sh  uci-defaults.sh

其中uci-defaults.sh会生成默认的/etc/config下的文件，而其它文件是它的“库”。

我们看一看uci-default.sh的内容

#!/bin/sh
# Copyright (C) 2011 OpenWrt.org

UCIDEF_LEDS_CHANGED=0

ucidef_set_led_netdev() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local dev=$4

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.trigger='netdev'
set system.$cfg.dev='$dev'
set system.$cfg.mode='link tx rx'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_led_usbdev() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local dev=$4

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.trigger='usbdev'
set system.$cfg.dev='$dev'
set system.$cfg.interval='50'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_led_wlan() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local trigger=$4

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.trigger='$trigger'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_led_switch() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local trigger=$4
    local port_mask=$5

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.trigger='$trigger'
set system.$cfg.port_mask='$port_mask'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_led_default() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local default=$4

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.default='$default'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_led_rssi() {
    local cfg="led_$1"
    local name=$2
    local sysfs=$3
    local iface=$4
    local minq=$5
    local maxq=$6
    local offset=$7
    local factor=$8

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='led'
set system.$cfg.name='$name'
set system.$cfg.sysfs='$sysfs'
set system.$cfg.trigger='rssi'
set system.$cfg.iface='rssid_$iface'
set system.$cfg.minq='$minq'
set system.$cfg.maxq='$maxq'
set system.$cfg.offset='$offset'
set system.$cfg.factor='$factor'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_set_rssimon() {
    local dev="$1"
    local refresh="$2"
    local threshold="$3"

    local cfg="rssid_$dev"

    uci -q get system.$cfg && return 0

    uci batch <<EOF
set system.$cfg='rssid'
set system.$cfg.dev='$dev'
set system.$cfg.refresh='$refresh'
set system.$cfg.threshold='$threshold'
EOF
    UCIDEF_LEDS_CHANGED=1
}

ucidef_commit_leds()
{
    [ "$UCIDEF_LEDS_CHANGED" == "1" ] && uci commit system
}

ucidef_set_interface_loopback() {
    uci batch <<EOF
set network.loopback='interface'
set network.loopback.ifname='lo'
set network.loopback.proto='static'
set network.loopback.ipaddr='127.0.0.1'
set network.loopback.netmask='255.0.0.0'
set network.globals='globals'
set network.globals.ula_prefix='auto'
EOF
}

ucidef_set_interface_raw() {
    local cfg=$1
    local ifname=$2

    uci batch <<EOF
set network.$cfg='interface'
set network.$cfg.ifname='$ifname'
set network.$cfg.proto='none'
EOF
}

ucidef_set_interface_lan() {
    local ifname=$1

    uci batch <<EOF
set network.lan='interface'
set network.lan.ifname='$ifname'
set network.lan.force_link=1
set network.lan.type='bridge'
set network.lan.proto='static'
set network.lan.ipaddr='192.168.1.1'
set network.lan.netmask='255.255.255.0'
set network.lan.ip6assign='60'
EOF
}

ucidef_set_interface_wan() {
    local ifname=$1

    uci batch <<EOF
set network.wan='interface'
set network.wan.ifname='$ifname'
set network.wan.proto='dhcp'
set network.wan6='interface'
set network.wan6.ifname='@wan'
set network.wan6.proto='dhcpv6'
EOF
}

ucidef_set_interfaces_lan_wan() {
    local lan_ifname=$1
    local wan_ifname=$2

    ucidef_set_interface_lan "$lan_ifname"
    ucidef_set_interface_wan "$wan_ifname"
}

ucidef_set_interface_macaddr() {
    local ifname=$1
    local mac=$2

    uci batch <<EOF
set network.$ifname.macaddr='$mac'
EOF
}

ucidef_add_switch() {
    local name=$1
    local reset=$2
    local enable=$3
    uci batch <<EOF
add network switch
set network.@switch[-1].name='$name'
set network.@switch[-1].reset='$reset'
set network.@switch[-1].enable_vlan='$enable'
EOF
}

ucidef_add_switch_vlan() {
    local device=$1
    local vlan=$2
    local ports=$3
    uci batch <<EOF
add network switch_vlan
set network.@switch_vlan[-1].device='$device'
set network.@switch_vlan[-1].vlan='$vlan'
set network.@switch_vlan[-1].ports='$ports'
EOF
}

ucidef_add_switch_port() {
    local device=$1
    local port=$2
    uci batch <<EOF
add network switch_port
set network.@switch_port[-1].device='$device'
set network.@switch_port[-1].port='$port'
EOF
}

看到了吧，改这里的内容就会改到openwrt固件的默认配置了。

调用这些库的函数在这里：

tf@ubuntu:~/projects/openwrt1407/target/linux/ar71xx/base-files/etc/uci-defaults$ ls
01_leds                       03_network-vlan-migration  09_fix-trx-header
02_network                    04_led_migration
03_network-switchX-migration  09_fix-seama-header

对于网络，则是02_network文件，看看该文件的开头内容为：

#!/bin/sh
#
# Copyright (C) 2011 OpenWrt.org
#

[ -e /etc/config/network ] && exit 0

touch /etc/config/network

. /lib/functions/uci-defaults.sh
. /lib/ar71xx.sh

ucidef_set_interface_loopback

board=$(ar71xx_board_name)

...

这样就清晰了。