windtear 追求完美

研究过 /sbin/ifup 的话 会发现 ifup 脚本有 vconfig 和 VLAN 支持的判断
(当时搞 ifup 的 bridge 支持也patch过这个脚本
 2005-04-08 19:01 hBridge - Linux Ethernet bridging)

# Ethernet 802.1Q VLAN support
if [ -x /sbin/vconfig -a "${VLAN}" = "yes" ]; then
    if echo ${DEVICE} | LANG=C egrep -v '(:)' | LANG=C egrep -q 'eth[0-9][0-9]*\.[0-9][0-9]?[0-9]?[0-9]?' ; then
        if [ ! -d /proc/net/vlan ]; then
            if modprobe 8021q >/dev/null 2>&1 ; then
                /sbin/vconfig set_name_type DEV_PLUS_VID_NO_PAD >/dev/null 2>&1 || {
                    echo $"Could not set 802.1Q VLAN parameters."
                }
            else
                echo $"No 802.1Q VLAN support available in kernel for device ${DEVICE}"
                exit 1
            fi
        fi
        VID="`echo ${DEVICE} | \
            LANG=C egrep 'eth[0-9]+\.[0-9][0-9]?[0-9]?[0-9]?$' | \
            LANG=C sed 's/^[a-z0-9]*\.//g;s/^0*//'`"
        PHYSDEV="`echo ${DEVICE} | \
            LANG=C egrep 'eth[0-9]+\.[0-9][0-9]?[0-9]?[0-9]?$' | \
            LANG=C sed 's/\.[a-z0-9]*$//g'`"

        is_available ${PHYSDEV} || {
            if [ "$?" = "1" ] ; then
                echo $"$alias device ${DEVICE} does not seem to be present, delaying initialization."
                exit 1
            else
                exit 0
            fi
        }

        # Link on Physical device needs to be up but no ip required
        check_device_down ${PHYSDEV} && {
            ip -o link set dev ${PHYSDEV} up
        }

        if [ ! -f /proc/net/vlan/${DEVICE} ]; then
            /sbin/vconfig add ${PHYSDEV} ${VID} || {
                (logger -p daemon.info -t ifup \
                    $"ERROR: could not add vlan ${VID} as ${DEVICE} on dev ${PHYSDEV}" &)&
                echo $"ERROR: could not add vlan ${VID} as ${DEVICE} on dev ${PHYSDEV}"
                exit 1
            }
        fi

        if [ -f /proc/net/vlan/${DEVICE} ]; then
            case "$REORDER_HDR" in
                yes|1)
                    /sbin/vconfig set_flag ${DEVICE} 1 1 || {
                        (logger -p daemon.info -t ifup \
                            "WARNING: vconfig not able to enable REORDER_HDR on ${DEVICE}" &)&
                    }
                    ;;
                no|0)
                    /sbin/vconfig set_flag ${DEVICE} 1 0 || {
                        (logger -p daemon.info -t ifup \
                            $"WARNING: vconfig not able to disable REORDER_HDR on ${DEVICE}" &)&
                    }
                    ;;
            esac
        fi
    fi
fi


vconfig 就是 Linux 下 802.1Q VLAN 实现配置工具
Name        : vconfig                      Relocations: (not relocatable)
Version     : 1.6                               Vendor: Red Hat, Inc.
Release     : 2                             Build Date: Sat 01 Feb 2003 06:20:05 AM CST
Install Date: Tue 01 Jun 2004 04:55:57 PM CST      Build Host: porky.devel.redhat.com
Group       : System Environment/Base       Source RPM: vconfig-1.6-2.src.rpm
Size        : 170822                           License: LGPL
Signature   : DSA/SHA1, Mon 24 Feb 2003 02:05:29 PM CST, Key ID 219180cddb42a60e
Packager    : Red Hat, Inc. 
URL         : http://www.candelatech.com/~greear/vlan.html
Summary     : Linux 802.1q VLAN configuration utility.
Description :
The vconfig program configures and adjusts 802.1q VLAN parameters.
/sbin/vconfig
/usr/share/doc/vconfig-1.6
/usr/share/doc/vconfig-1.6/CHANGELOG
/usr/share/doc/vconfig-1.6/README
/usr/share/doc/vconfig-1.6/contrib
/usr/share/doc/vconfig-1.6/contrib/CVS
/usr/share/doc/vconfig-1.6/contrib/CVS/Entries
/usr/share/doc/vconfig-1.6/contrib/CVS/Repository
/usr/share/doc/vconfig-1.6/contrib/CVS/Root
/usr/share/doc/vconfig-1.6/contrib/README
/usr/share/doc/vconfig-1.6/contrib/vlan_2.2-full.patch
/usr/share/doc/vconfig-1.6/contrib/vlan_2.2-module.patch
/usr/share/doc/vconfig-1.6/vlan.html
/usr/share/doc/vconfig-1.6/vlan_test.pl
/usr/share/man/man8/vconfig.8.gz

% vconfig
Expecting argc to be 3-5, inclusive.  Was: 1

Usage: add             [interface-name] [vlan_id]
       rem             [vlan-name]
       set_flag        [interface-name] [flag-num]       [0 | 1]
       set_egress_map  [vlan-name]      [skb_priority]   [vlan_qos]
       set_ingress_map [vlan-name]      [skb_priority]   [vlan_qos]
       set_name_type   [name-type]

* The [interface-name] is the name of the ethernet card that hosts
  the VLAN you are talking about.
* The vlan_id is the identifier (0-4095) of the VLAN you are operating on.
* skb_priority is the priority in the socket buffer (sk_buff).
* vlan_qos is the 3 bit priority in the VLAN header
* name-type:  VLAN_PLUS_VID (vlan0005), VLAN_PLUS_VID_NO_PAD (vlan5),
              DEV_PLUS_VID (eth0.0005), DEV_PLUS_VID_NO_PAD (eth0.5)
* bind-type:  PER_DEVICE  # Allows vlan 5 on eth0 and eth1 to be unique.
              PER_KERNEL  # Forces vlan 5 to be unique across all devices.
* FLAGS:  1 REORDER_HDR  When this is set, the VLAN device will move the
            ethernet header around to make it look exactly like a real
            ethernet device.  This may help programs such as DHCPd which
            read the raw ethernet packet and make assumptions about the
            location of bytes.  If you don't need it, don't turn it on, because
            there will be at least a small performance degradation.  Default
            is OFF.

----->   在eth0接口配置两个vlan  如果没有加载模块会自动加载8021q模块
vconfig add eth0 11
vconfig add eth0 21

----->   设置参数 REORDER_HDR (默认就是)
vconfig set_flag eth0.11 1 1
vconfig set_flag eth0.21 1 1

----->   查看一下
cat /proc/net/vlan/eth0.11
cat /proc/net/vlan/eth0.21

----->   改接口启动配置文件
cd /etc/sysconfig/network-scripts/
cp ifcfg-eth0 ifcfg-eth0.11
perl -pi -e 's/DEVICE=eth0/DEVICE=eth0.11/g' ifcfg-eth0.11
cp ifcfg-eth0 ifcfg-eth0.21
perl -pi -e 's/DEVICE=eth0/DEVICE=eth0.21/g' ifcfg-eth0.21

perl -pi -e 's/IPADDR=/#IPADDR=/g' ifcfg-eth0
perl -pi -e 's/NETMASK=/#NETMASK=/g' ifcfg-eth0
......

----->   手工切换 这时需要更改交换机配置
ifdown eth0;ifup eth0;ifup eth0.11;ifup eth0.21

----->   设置下次启动自动加载 8021q 模块
echo VLAN=yes >> /etc/sysconfig/network