1-Openwrt ipv6之-odhcp6c客户端

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已于 2024-09-06 12:33:54 修改

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分类专栏： Openwrt 文章标签： spring java 前端

于 2024-09-06 12:11:55 首次发布

原文链接：https://blog.youkuaiyun.com/Creator_Ly/article/details/106992333

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wan口的拨号有好几种方式，SLAAC, stateless DHCPv6, stateful DHCPv6, DHCPv6-PD，这些请求方式在odhcpv6里面都可以配置。

1. odhcp6c客户端启动过程

开启openwrt .config配置

CONFIG_PACKAGE_odhcp6c=y
CONFIG_PACKAGE_odhcp6c_ext_prefix_class=0
CONFIG_PACKAGE_odhcp6c_ext_cer_id=0

odhcp6c的启动需要在/etc/config/network uci里面配置允许，类似IPV4的udhcpc

config globals 'globals'
        option ula_prefix 'auto'

config interface 'lan'
        option def_ifname 'eth0'
        option ifname 'eth0'
        option force_link '1'
        option type 'bridge'
        option proto 'static'
        option igmp_snooping '0'
        option ipaddr '192.168.18.1'
        option def_ipaddr '192.168.18.1'
        option res_ipaddr '10.1.2.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option macaddr 'DC:4B:DD:1D:FA:48'

config interface 'wan'
        option ipv6 '1'
        option def_ifname 'eth1'
        option ifname 'eth1'
        option proto 'dhcp'
        option web_proto 'dhcp'
        option macaddr 'DC:4B:DD:1d:fa:49'

config interface 'wan6'
        option ifname   'eth1'
        option proto    'dhcpv6'

配置好之后需要重启/etc/init.d/network restart里面会执行ubus call network reload然后就是一系列的ubus传输，最终会调用到/lib/netifd/proto里面对应的脚本，脚本netifd-proto.sh脚本里面会调用_proto_do_setup函数，启动各个协议进程。

/lib/netifd/proto$ ls
dhcp.sh

1.1 IPV4 CLIENT udhcpc启动
ipv4的启动在./lib/netifd/proto/dhcp.sh脚本里面的proto_dhcp_setup函数

dhcp.sh脚本属于netifd-2014-09-08.1模块
udhcpc可执行程序属于busybox-1.22.1模块

proto_export "INTERFACE=$config"
    proto_run_command "$config" udhcpc -R \
        -p /var/run/udhcpc-$iface.pid \
        -s /lib/netifd/dhcp.script \
        -f -t 0 -i "$iface" \
        ${ipaddr:+-r $ipaddr} \
        ${hostname:+-H $hostname} \
        ${vendorid:+-V $vendorid} \
        $clientid $broadcast $dhcpopts

1.2 IPV6 CLIENT odhcp6c启动
ipv6的启动在./lib/netifd/proto/dhcpv6.sh脚本里面的proto_dhcpv6_setup函数

dhcpv6.sh脚本和odhcp6c都属于odhcp6c-2014-12-10模块

proto_export "INTERFACE=$config"
    proto_run_command "$config" odhcp6c \
        -s /lib/netifd/dhcpv6.script \
        $opts $iface

udhcpc -R -p /var/run/udhcpc-eth1.pid -s /lib/netifd/dhcp.script -f -t 0 -i eth1 -C
odhcp6c -s /lib/netifd/dhcpv6.script -P0 -t120 eth1

1.3 进程查看
odhcp6c启动之后，在netstat下面可以看到udp的546端口，因为DHCPv6的客户端使用546端口，服务器使用的是547端口

root@openwrt:/# netstat -naup | grep dhcp
netstat: showing only processes with your user ID
udp        0      0 :::546                  :::*                                1481/odhcp6c
udp        0      0 :::547                  :::*                                1347/odhcpd

odhcp6c拨号方式选择
上面提到了wan口的拨号是有很多种的，而且wan口的ifname也是会变化的。
2.1 dhcpv6方式
wan口拨号的uci配置在官网可以查看到
https://openwrt.org/docs/guide-user/network/ipv6/start

在这里插入图片描述

config globals 'globals'
        option ula_prefix 'auto'

config interface 'lan'
        option proto 'static'
        option ip6assign '60'

config interface 'wan6'
        option ifname   'eth1'
        option proto    'dhcpv6'

所以默认情况，udhcp6c的dhcpv6使用SLAAC + stateful DHCPv6 + DHCPv6-PD的方式进行拨号的。

所以路由器wan口获取到多少个ipv6地址，就看上一级的服务器能提供多少种服务。

如果上级只有dhcpv6服务器，则wan只获取到一个Global 地址,加上自己本地的Link地址，是两个ipv6地址

root@openwrt:/# ifconfig eth1
eth1      Link encap:Ethernet  HWaddr 08:10:7B:A7:26:3C  
          inet6 addr: fe80::a10:7bff:fea7:263c/64 Scope:Link
          inet6 addr: 2001:db8:0:1::254/128 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1510 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3731 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:252070 (246.1 KiB)  TX bytes:501125 (489.3 KiB)

如果上级既有dhcpv6服务器，也有ra服务器，则就会有三个地址,一个本地Link,一个dhcp服务器分配的Global地址，一个ra服务器下发前缀算出来的Global地址。

eth1      Link encap:Ethernet  HWaddr 08:10:7B:A7:26:3C  
          inet6 addr: 2016:ac11:5cad:0:a10:7bff:fea7:263c/64 Scope:Global
          inet6 addr: fe80::a10:7bff:fea7:263c/64 Scope:Link
          inet6 addr: 2001:db8:0:1::254/128 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2288 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5709 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:387179 (378.1 KiB)  TX bytes:830273 (810.8 KiB)

支持DHCP-PD功能，所以在发送DHCP Solicit消息里面如果带了IA-Prefix的请求，则服务器就会在IA Prefix字段里面附带自己要在br-lan端口设置的ipv6端口地址前缀，2001:db8:0:f00::1/60，用于下发地址给lan口的设备的地址前缀，然后设置到br-lan的ifconfig里面。

在odhcp6c客户端发送DHCP-PD之后，会在br-lan口设置dhcp服务器的IP前缀，如下2001:db8:0:f00::，这样lan端就可以使用这个前缀地址通过odhcpd服务器下发给下一级ipv6地址了。

root@openwrt:/# ifconfig br-lan
br-lan    Link encap:Ethernet  HWaddr 08:10:7B:A7:26:3B  
          inet addr:192.168.18.1  Bcast:192.168.18.255  Mask:255.255.255.0
          inet6 addr: 2001:db8:0:f00::1/60 Scope:Global
          inet6 addr: fe80::a10:7bff:fea7:263b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:391 errors:0 dropped:0 overruns:0 frame:0
          TX packets:248 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:32339 (31.5 KiB)  TX bytes:74394 (72.6 KiB)

2.2 staticv6方式
ohdcp6c的静态IP方式将uci的值单独抽出来，没有跟上面的在一起，主要有如下参数
在这里插入图片描述

# cat /etc/config/network
config interface wan
        option ifname   eth1
        option proto    static
        option ip6addr  2001:db80::2/64   # Own address
        option ip6gw    2001:db80::1      # Gateway address
        option ip6prefix 2001:db80:1::/48 # Prefix addresses for distribution to downstream interfaces
        option dns      2001:db80::1      # DNS server
 
config interface lan
        option proto    static
        option ip6assign 60

上面这种方式就把wan接口配置成静态ipv6了模式了，这样ipv4也得是静态模式，所以一般在wan6里面设置成static，而wan里面ipv4的还是正常的dhcp/static

# cat /etc/config/network
config interface 'wan'
        option ipv6 '1'
        option def_ifname 'eth1'
        option ifname 'eth1'
        option proto 'dhcp'
        option web_proto 'dhcp'
        option macaddr 'DC:4B:DD:1d:fa:49'
        
config interface 'wan6'
        option ifname   eth1
        option proto    static
        option ip6addr  2001:db80::2/64   # Own address
        option ip6gw    2001:db80::1      # Gateway address
        option ip6prefix 2001:db80:1::/48 # Prefix addresses for distribution to downstream interfaces
        option dns      2001:db80::1      # DNS server
 
config interface lan
        option proto    static
        option ip6assign 60

查看ipv6信息
在获取到ipv6地址后，除了使用ifconfig看下信息外，还可以使用ifstatus查看

root@openwrt:/tmp/state# ifstatus wan6
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "uptime": 3195,
        "l3_device": "apcli0",
        "proto": "dhcpv6",
        "device": "apcli0",
        "metric": 0,
        "delegation": true,
        "ipv4-address": [

        ],
        "ipv6-address": [
                {
                        "address": "240e:ff:b112:7b52:dc4b:ddff:fe1d:fa08",
                        "mask": 64
                }
        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "240e:ff:b112:7b52::",
                        "mask": 64,
                        "nexthop": "::",
                        "metric": 256,
                        "source": "::\/0"
                },
                {
                        "target": "::",
                        "mask": 0,
                        "nexthop": "fe80::1c6e:5292:2b90:603",
                        "metric": 1024,
                        "valid": 8961,
                        "source": "240e:ff:b112:7b52:dc4b:ddff:fe1d:fa08\/64"
                },
                {
                        "target": "::",
                        "mask": 0,
                        "nexthop": "fe80::1c6e:5292:2b90:603",
                        "metric": 1024,
                        "valid": 8961,
                        "source": "::\/128"
                }
        ],
        "dns-server": [
                "fe80::1c6e:5292:2b90:603"
        ],
        "dns-search": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ]
        },
        "data": {
                "passthru": "00170010fe800000000000001c6e52922b900603"
        }
}

手机热点的测试
现在的手机热点，一般都可以提供ipv6地址，中继成功后获取到如下ipv6地址，跟手机在同一个网段

手机可以在http://www.test-ipv6.com/上面看到自己的网段

然后路由器设置成无线中继模式，连接手机的热点，wan6的ifname设置成apcli0，dhcpv6模式

config interface 'wan6'
        option ifname   'apcli0'
        option proto    'dhcpv6'

连接成功后，可以看到以下信息，一个本地链路地址和一个全球单播地址。

root@openwrt:/tmp/state# ifconfig apcli0
apcli0    Link encap:Ethernet  HWaddr DE:4B:DD:1D:FA:08
          inet addr:172.20.10.13  Bcast:172.20.10.15  Mask:255.255.255.240
          inet6 addr: 240e:ff:b112:7b52:dc4b:ddff:fe1d:fa08/64 Scope:Global
          inet6 addr: fe80::dc4b:ddff:fe1d:fa08/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:33129 errors:0 dropped:0 overruns:0 frame:0
          TX packets:36694 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:16662784 (15.8 MiB)  TX bytes:4734313 (4.5 MiB)

使用手机热点获取到的Global ipv6地址是通过EUI64自己算出来的，所以这个地址应该不是dhcpv6服务器下发的，而是通过RA无状态模式生成的。

另外可以看到路由器的br-lan端口是没有全球单播地址的，路由器发出的IA-PD手机没办法回复，没有提供给下一级设备使用的地址。

这时候可以在lan口设置一个同网段的ipv6地址，这样lan端的设备就可以获取到ipv6地址，不过担心会冲突吧，比较不是正在的dhcpv6/ra服务器下发的

root@openwrt:/# ifconfig apcli0
apcli0    Link encap:Ethernet  HWaddr DE:4B:DD:1D:FA:08
          inet addr:172.20.10.13  Bcast:172.20.10.15  Mask:255.255.255.240
          inet6 addr: 240e:ff:b4d5:621d:dc4b:ddff:fe1d:fa08/64 Scope:Global
          inet6 addr: fe80::dc4b:ddff:fe1d:fa08/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10193 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10338 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:9429739 (8.9 MiB)  TX bytes:3842656 (3.6 MiB)

root@openwrt:/# ifconfig br-lan add 240e:ff:b4d5:621d:dc4b:ddff:fe1d:fa08/64
root@openwrt:/# ifconfig br-lan
br-lan    Link encap:Ethernet  HWaddr DC:4B:DD:1D:FA:48
          inet addr:192.168.18.1  Bcast:192.168.18.255  Mask:255.255.255.0
          inet6 addr: 240e:ff:b4d5:621d:dc4b:ddff:fe1d:fa08/64 Scope:Global
          inet6 addr: fe80::de4b:ddff:fe1d:fa48/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2742 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1626 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:526741 (514.3 KiB)  TX bytes:441983 (431.6 KiB)

root@openwrt:/#ifconfig br-lan add 240e:ff:b112:7b52::2012/64