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OpenWrt/PandoraBox多网段中继转发mDNS Reflector

发布时间:February 12, 2022 // 分类: // No Comments

为了安全将物联网设备单独使用一个网段和本地网络隔离,这样基于mdns协议的发现应用就不能使用了,如电视投屏、打印机等,可以使用mDNS Reflector来中继两个网段的mdns。
编译方法参考:k2p交叉编译smartdns/openssl

/usr/local/bin/mdns-reflector -n br-lan br-robot br-guest

路由配置iptables防火墙允许udp 5353入,并允许本地网络访问电视所在的网络:

iptables -A INPUT -i br-robot -p udp --dport 5353 -j ACCEPT
iptables -A FORWARD -i br-lan -j ACCEPT
iptables -A FORWARD -i robot -o br-lan -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

openresty/nginx lua动态更新stream upstream/tcp udp端口转发服务器

发布时间:February 7, 2022 // 分类: // No Comments

有一应用需动态更新目标的ip和端口,使用nginx/openresty tcp/udp端口转发配合lua扩展很方便实现。

stream {
    lua_shared_dict ups_dict 1m;
    lua_shared_dict ups_list 1m;
    lua_add_variable $ups_name;
    #当nginx启动或reload时读取配置文件内upstream列表到lua_shared_dict,更新后端的时候判断是否有效
    init_by_lua_block {
       ngx.shared.ups_list:flush_all()
       local file = "/etc/nginx/stream.conf"
       local f = io.open(file, "r")
       local content = f:read("*a")
       f:close()
       for substr in string.gmatch(content, "upstream%s+([%w-_]+)%s+%{") do
           ngx.log(ngx.WARN, substr)
           ngx.shared.ups_list:set(substr, 1)
       end
    }
  
    log_format main '$remote_addr [$time_local] '
                    '$protocol $status $bytes_sent $bytes_received '
                    '$session_time "$upstream_addr" '
                    '"$upstream_bytes_sent" "$upstream_bytes_received" "$upstream_connect_time"';
    access_log /run/log/nginx/dns_access.log main;
    error_log  /run/log/nginx/dns_error.log error;
    #log level: debug, info, notice, warn, error (default), crit, alert, and emerg.

    upstream default_tcp {
        server 127.0.0.1:53;
        server 127.0.0.1:55;
    }
    upstream default_udp {
        server 10.0.1.1:53;
        server 10.0.2.1:53;
    }
    upstream default_udp2 {
        server 10.0.3.1:53;
        server 10.0.3.2:53;
    }
    upstream test1_tcp {
        server 127.0.0.1:53;
    }
    upstream test1_udp {
        server 10.0.1.1:53;
    }
    upstream test1_udp2 {
        server 10.0.3.2:53;
    }
    upstream test2_tcp {
        server 127.0.0.1:55;
    }
    upstream test2_udp {
        server 10.0.2.1:53;
    }
    upstream test2_udp2 {
        server 10.0.3.1:53;
    }

    server {
        listen     53000 udp;
        preread_by_lua_block {
            assert(not ngx.var.ups_name)
            local ups = ngx.shared.ups_dict:get("ups_name")
            if ups ~= nil then
                ngx.log(ngx.WARN, "udp 53000 use " .. ups .. " upstream")
                ngx.var.ups_name = ups .. "_udp"
            else
                ngx.log(ngx.WARN, "udp 53000 use default upstream")
                ngx.var.ups_name = "default_udp"
            end
        }
        proxy_pass $ups_name;
        proxy_responses 1; #当返回一个udp数据包时就关闭连接,或proxy_timeout时间内无数据关闭连接
        proxy_connect_timeout 1s;
        proxy_timeout 5s;
    }
    server {
        listen     53000;
        preread_by_lua_block {
            assert(not ngx.var.ups_name)
            local ups = ngx.shared.ups_dict:get("ups_name")
            if ups ~= nil then
                ngx.log(ngx.WARN, "tcp 53000 use " .. ups .. " upstream")
                ngx.var.ups_name = ups .. "_tcp"
            else
                ngx.log(ngx.WARN, "tcp 53000 use default upstream")
                ngx.var.ups_name = "default_tcp"
            end
        }
        proxy_pass $ups_name;
        #proxy_responses 1; #当返回一个udp数据包时就关闭连接,或proxy_timeout时间内无数据关闭连接
        proxy_connect_timeout 1s;
        proxy_timeout 5s;
    }
    server {
        listen     53001 udp;
        preread_by_lua_block {
            assert(not ngx.var.ups_name)
            local ups = ngx.shared.ups_dict:get("ups_name")
            if ups ~= nil then
                ngx.log(ngx.WARN, "udp 53001 use " .. ups .. " upstream")
                ngx.var.ups_name = ups .. "_udp2"
            else
                ngx.log(ngx.WARN, "udp 53001 use default upstream")
                ngx.var.ups_name = "default_udp2"
            end
        }
        proxy_pass $ups_name;
        proxy_responses 1; #当返回一个udp数据包时就关闭连接,或proxy_timeout时间内无数据关闭连接
        proxy_connect_timeout 1s;
        proxy_timeout 5s;
    }


    server {
        listen 53001;

        content_by_lua_block {
            local sock = assert(ngx.req.socket(true))
            local data = sock:receive()
            local args, err = ngx.decode_args(data, 0)
            if err == nil then
                for k,v in pairs(args) do
                    --ngx.say(v)
                    ip = v:match("(%d+%.%d+%.%d+%.%d+%:%d+)")
                    if ip ~= nil then
                        local sus, err = ngx.shared.ups_dict:set(k, ip)
                        if sus then
                            ngx.say("set upstream sus: " .. k .. "=" .. ip)
                        else
                            ngx.say(err)
                        end
                    end
                end
            end
        }
        access_log off;
    }
    server {
        listen 53002;

        content_by_lua_block {
            local sock = assert(ngx.req.socket(true))
            local data = sock:receive()
            if data then
                local args, err = ngx.decode_args(data, 0)
                if err == nil then
                    for k,v in pairs(args) do
                        --ngx.say(v)
                        --if k == "name" and type(v) == "string" and v:find("dns") then
                        if k == "name" and type(v) == "string" and ngx.shared.ups_list:get(v .. "_udp")  then
                            local sus, err = ngx.shared.ups_dict:set("ups_name", v)
                            if sus then
                                ngx.say("set upstream sus: " .. k .. "=" .. v)
                                ngx.log(ngx.WARN, "set upstream sus: " .. k .. "=" .. v)
                            else
                                ngx.say(err)
                            end
                        end
                    end
                end
            end
        }
        access_log off;
    }
}

使用nc测试设置nginx转发使用的后端upstream名称:

nc 127.0.0.1 53002
name=test1
set upstream sus: name=test1

也可通过53001端口设置目标ip:port,然后proxy_pass即可。
参考:
https://github.com/openresty/lua-resty-core/blob/master/lib/ngx/balancer.md
https://xiangxianzui.github.io/2017/11/nginx-lua%E5%8A%A8%E6%80%81%E6%94%B9%E5%8F%98upstream/

openwrt/PandoraBox使用dnsmasq替换odhcpd提供SLAAC分配ip及禁用ipv6 dns

发布时间:January 24, 2022 // 分类:DNS // No Comments

先在配置文件内禁用ipv6 dhcp服务:

/etc/config/dhcp 
config dhcp 'lan'
        option interface 'lan'
        option start '150'
        option limit '100'
        option leasetime '12h'
        option ra 'disabled'
        option dhcpv6 'disabled'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'

关闭odhcpd:

/etc/init.d/odhcpd stop
/etc/init.d/odhcpd disable

修改dnsmasq配置文件开启ra服务:

/etc/dnsmasq.conf 
enable-ra
dhcp-range=::,constructor:br-lan,ra-only
#其它slaac ra-stateless等参考man文档

只想通过ipv4查询dns,下面patch让dnsmasq无状态分配ip时候不包含RDNSS,这样客户端只配置ipv4 dns而不配置ipv6 dns。

diff -urN dnsmasq-2.86/src/radv.c dnsmasq-2.86-bak/src/radv.c
--- dnsmasq-2.86/src/radv.c     2021-09-09 04:21:22.000000000 +0800
+++ dnsmasq-2.86-bak/src/radv.c 2022-01-23 11:57:01.818963642 +0800
@@ -507,7 +507,7 @@
        }
     }
 
-  if (daemon->port == NAMESERVER_PORT && !done_dns && parm.link_pref_time != 0)
+  if ( 0 && daemon->port == NAMESERVER_PORT && !done_dns && parm.link_pref_time != 0)
     {
       /* default == us, as long as we are supplying DNS service. */
       put_opt6_char(ICMP6_OPT_RDNSS);

odhcpd新版本参数dns_service也可实现此需求。
再次开启ipv6 dns服务,如果有配置dhcp6 dns服务器,dnsmasq会将其设置为RDNSS:

dhcp-option=option6:dns-server,[xxxx:xxxx:xxxx:xxxx::1]

dnsmasql设置客户端add-subnet edns ip缓存问题

发布时间:January 24, 2022 // 分类: // No Comments

路由上跑dnsmasq通过将客户端ip添加为edns ip转发到其它dns服务器时可以根据客户端ip做相应操作,dnmasq只有在设置add-subnet为固定ip段时才缓存,add-subnet=32时动态添加客户端ip为edns ip时不缓存,做了下修改可以缓存。

--- dnsmasq-2.86/src/edns0.c    2021-09-09 04:21:22.000000000 +0800
+++ dnsmasq-2.86-bak/src/edns0.c        2022-01-23 18:54:04.801336879 +0800
@@ -375,6 +375,7 @@
   if (cacheablep)
     *cacheablep = cacheable;
   
+  *cacheablep = 1;
   return len + 4;
 }
  
diff -urN dnsmasq-2.86/src/forward.c dnsmasq-2.86-bak/src/forward.c
--- dnsmasq-2.86/src/forward.c  2021-09-09 04:21:22.000000000 +0800
+++ dnsmasq-2.86-bak/src/forward.c      2022-01-23 18:58:25.020648204 +0800
@@ -596,7 +596,7 @@
       /* Get extended RCODE. */
       rcode |= sizep[2] << 4;
 
-      if (check_subnet && !check_source(header, plen, pheader, query_source))
+      if ( 0 && check_subnet && !check_source(header, plen, pheader, query_source))
        {
          my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch"));
          return 0;

mosdns删除dns返回结果中的cname直接返回a记录插件

发布时间:January 18, 2022 // 分类: // No Comments

unbound做mosdns前置的时候会重新查询域名返回的dns cname记录,这样mosdns做dns域名分流的时候还要额外添加cname域名规则,写了一个mosdns插件删除cname信息直接返回a记录避免二次查询。

//dispatcher/plugin/executable/dcname/dcname.go
package dcname

import (
  "context"
  "github.com/IrineSistiana/mosdns/v3/dispatcher/handler"
  "github.com/IrineSistiana/mosdns/v3/dispatcher/pkg/dnsutils"
  "github.com/miekg/dns"
)

const (
  PluginType = "dcname"
)

func init() {
  handler.RegInitFunc(PluginType, Init, func() interface{} { return new(Args) })
}

var _ handler.ExecutablePlugin = (*dcname)(nil)

type Args struct {
}

type dcname struct {
  *handler.BP
  args *Args
}

func Init(bp *handler.BP, args interface{}) (p handler.Plugin, err error) {
  return newDcname(bp, args.(*Args)), nil
}

func newDcname(bp *handler.BP, args *Args) handler.Plugin {
  return &dcname{
    BP:   bp,
    args: args,
  }
}

func (t *dcname) Exec(ctx context.Context, qCtx *handler.Context, next handler.ExecutableChainNode) error {
  if r := qCtx.R(); r != nil {
    q := qCtx.Q()
    if (len(q.Question) == 1 && len(r.Answer) >= 1) {
      qname := q.Question[0].Name
      qtype := q.Question[0].Qtype
      rname := r.Answer[0].Header().Name
      rtype := r.Answer[0].Header().Rrtype
      if ((qtype == dns.TypeA || qtype == dns.TypeAAAA) && qname == rname && rtype == dns.TypeCNAME) {
        var Answer2 []dns.RR
        for i := range r.Answer {
          var rr2 dns.RR
          switch rr := r.Answer[i].(type) {
          case *dns.A:
            rr2 = &dns.A{
              Hdr: dns.RR_Header{
                Name:   qname,
                Rrtype: dns.TypeA,
                Class:  dns.ClassINET,
                Ttl:    r.Answer[i].Header().Ttl,
              },
              A: rr.A,
            }
          case *dns.AAAA:
            rr2 = &dns.AAAA{
              Hdr: dns.RR_Header{
                Name:   qname,
                Rrtype: dns.TypeAAAA,
                Class:  dns.ClassINET,
                Ttl:    r.Answer[i].Header().Ttl,
              },
              AAAA: rr.AAAA,
            }
          default:
            continue
          }
          Answer2 = append(Answer2, rr2)
        }
        r.Answer = Answer2
      }
    }
  }
  return handler.ExecChainNode(ctx, qCtx, next)
}

开启插件:

dispatcher/plugin/enabled_plugin.go 
_ "github.com/IrineSistiana/mosdns/v3/dispatcher/plugin/executable/dcname"

qCtx.Q()和qCtx.R()分别获取查询和返回的信息,*dns.Msg定义在:
https://github.com/miekg/dns/blob/master/msg.go#L109
查询信息Question []Question定义在:
https://github.com/miekg/dns/blob/master/types.go#L228
返回信息Answer RR[]定义在:
https://github.com/miekg/dns/blob/master/dns.go#L31
Answer Header:
https://github.com/miekg/dns/blob/master/dns.go#L67
DNS TYPE:
https://github.com/miekg/dns/blob/master/types.go#L25

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