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宽带重新拨号会重新分配ipv6前缀，有的设备仍然优先使用旧的ip段，导致ipv6不能使用，可减小preferred_lifetime时间使旧的ip段快速失效。
openwrt dhcp提供preferred_lifetime参数设置preferred时间，需要将ra_useleasetime启用才有效，同时会将valid_lifetime修改为leasetime时间。

option leasetime '2h' 
option ra_lifetime 1200
option ra_useleasetime '1'
option preferred_lifetime '10m'

odhcpd源码判断设置preferred_lifetime和valid_lifetime：

src/router.c
if (addr->preferred > (uint32_t)now) {
        preferred = TIME_LEFT(addr->preferred, now);

        if (iface->ra_useleasetime &&
                        preferred > iface->preferred_lifetime)
                preferred = iface->preferred_lifetime;
}

valid = TIME_LEFT(addr->valid, now);
if (iface->ra_useleasetime && valid > iface->dhcp_leasetime)
        valid = iface->dhcp_leasetime;

使用wireshark查看效果：

也可用tcpdump查看：

tcpdump -i br-lan -nn "icmp6 && ip6[40] == 134" -vv

使用udpxy和msd_lite都有一些小问题，参考多方用golang写了个简单rtp多播转http单播，无缓存，cpu占用有点小高，效果不错。

package main

import (
    "flag"
    "fmt"
    "github.com/pion/rtp"
    "io"
    "net"
    "net/http"
    //"strings"
    "time"
)

var timeout = 2000 * time.Millisecond
var readbuffer = 2 * 1024 * 1024
var buffer = 1500

const (
    RTP_Payload_MP2T = 33
    ContentType_MP2T    = "video/MP2T"
    ContentType_DEFAULT = "application/octet-stream"
)

var McastIface = flag.String("m", "eth1.23", "mcast iface (IP addr or name)")
var ListenAddr = flag.String("a", "0.0.0.0", "http listen addr (default 0.0.0.0)")
var ListenPort = flag.Int("p", 8080, "http listen port (default 8080)")

func main() {
    flag.Parse()
    http.HandleFunc("/", handler)
    fmt.Printf("http listen: %s:%d\n", *ListenAddr, *ListenPort)
    err := http.ListenAndServe(fmt.Sprintf("%s:%d", *ListenAddr, *ListenPort), nil)
    if err != nil {
        panic(err)
    }
}

var tag = "/udp/"
var tagLen = len(tag)

func handler(w http.ResponseWriter, r *http.Request) {
    var err error
    defer func(w http.ResponseWriter, r *http.Request) {
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            io.WriteString(w, err.Error()+"\n")
        }
        fmt.Println(time.Now().Format("2006-01-02 15:04:05"), "close http: "+r.RemoteAddr)
    }(w, r)

    path := r.URL.Path
    if len(path) < tagLen {
        w.WriteHeader(http.StatusBadRequest)
        io.WriteString(w, "No address specified\n")
        return
    }

    addr := path[tagLen:]
    fmt.Println(time.Now().Format("2006-01-02 15:04:05"), addr, r.RemoteAddr)

    conn, err := newMulticastReader(addr)
    if err != nil {
        return
    }

    defer func() {
        _ = conn.Close()
        fmt.Println(time.Now().Format("2006-01-02 15:04:05"), "close udp: "+addr)
    }()

    w.Header().Set("X-Content-Type-Options", "nosniff")
    conn.SetReadBuffer(readbuffer)
    headerSent := false
    p := &rtp.Packet{}
    var buf = make([]byte, buffer)
    for {
        conn.SetReadDeadline(time.Now().Add(timeout))
        n, err := conn.Read(buf)
        if err != nil {
            fmt.Println("read err:", err)
            w.WriteHeader(http.StatusInternalServerError)
            io.WriteString(w, err.Error())
            return
        }

        //fmt.Println(time.Now(), n, "buf len:", len(buf))
        if err = p.Unmarshal(buf[:n]); err != nil {
            fmt.Println("unpack err:", err)
            return
        }
        if !headerSent {
            headerSent = true
            if p.PayloadType == RTP_Payload_MP2T {
                w.Header().Set("Content-Type", ContentType_MP2T)
            } else {
                w.Header().Set("Content-Type", ContentType_DEFAULT)
            }
            w.WriteHeader(http.StatusOK)
        }
        if _, err = w.Write(p.Payload); err != nil {
            return
        }
    }
}

func newMulticastReader(address string) (conn *net.UDPConn, err error) {
    addr, err := net.ResolveUDPAddr("udp", address)
    if err != nil {
        return
    }
    //fmt.Printf(time.Now().Format("2006-01-02 15:04:05")+" multicast: listen addr %s\n", address)
    iface, err := net.InterfaceByName(*McastIface)
    conn, err = net.ListenMulticastUDP("udp", iface, addr)
    if err != nil {
        panic(err)
    }
    return
}

参考：
https://github.com/hello-xnew/gdpxy
https://github.com/darren/retv

修改密码后依旧如此，修改/etc/shadow用户第三个字段为正整数即可：

cat /etc/shadow
user:$1$ercaZtGB$S8x9tyPTC1Bd8Litu7irt/:17000:0:99999::::

https://blog.csdn.net/baidu_31381143/article/details/53976386

由于移动默认使用password认证，先开启telnet http://192.168.1.1/system.cgi?telnet，通过telnet登录切换到电信界面用loid认证，只要olt认证成功，配置手工创建，此猫固件不包含联通界面。

ritool set Custom AH

重启后在web界面恢复出厂设置，电信用户名: telecomadmin密码: nE7jA%5m，移动用户名：CMCCAdmin 密码：aDm8H%MdA

ttl连接，电路板正面网口朝上，ttl针脚从上面开始依次为RX,TX,GND

启动后进入shell：

enable
shell
LA(ImvZx%8

https://www.chinadsl.net/forum.php?mod=viewthread&tid=172429
https://blog.ylx.me/archives/691.html