有没有可能自动获取DHCP派发下来的DNS地址

[laggardkernel]

目前对于 .lan 域名，需要转发给路由器下发的DNS，以支持解析到局域网内其他设备。有没有可能自定识别出上游DHCP下发的DNS地址？现在我只能写死这种地址，根据不同网络还要去更改它。

目前我知道 NetworkManager 会将DHCP DNS信息存盘

The original DNS servers can be found in /run/NetworkManager/no-stub-resolv.conf.

Clash 好像也实现了这种功能 https://github.com/Dreamacro/clash/pull/1509

提供部分相关配置说明一下我要做什么

  - tag: chinadns_entry
    type: sequence
    args:
      exec:
        - match_hosts
        - _default_cache
        - _single_flight
        ...
        - if:
          - match_lan_domain
          exec:
            - forward_dhcp
            - _end
          ...

  - tag: 'forward_dhcp'
    type: fast_forward
    args:
      upstream:
        - addr: udp://192.168.2.1:53
      timeout: 3
  - tag: match_lan_domain
    type: query_matcher
    args:
      logical_and: true
      domain:
        - 'domain:lan'
        # - 'regexp:.+\.lan\.?$'
      qtype: [1, 28]
      qclass: [1]

[IrineSistiana]

有可能。看 clash 的 commit 它是做了一个 dhcp 客户端然后去拉服务端的数据。工作量有点大.....

我有个懒人的想法: 让 mosdns 运行后去运行一个 bash 脚本去获取 dns 服务器地址。

[IrineSistiana]

功能有了。现在配置文件里可以加 ${{ cmd }} 语法。里面的 cmd 会被执行，然后自身会被 cmd 的输出替换。就跟 bash 的 $( cmd ) 一样。

所以可以自己写一个脚本 get_dhcp_dns.sh ，获取 IP，然后配置写成

tag: 'forward_dhcp'
    type: fast_forward
    args:
      upstream:
        - addr: ${{ ./get_dhcp_dns.sh }}
      timeout: 3

[QiuSimons]

前面不需要加 - addr: 么？

要。我漏了。

加上以后会有更奇怪的报错，稍等我截个log

[QiuSimons]

- addr: ${{ ./get_dhcp_dns.sh }}

这是脚本执行的结果
root@OpenWrt:~# /etc/mosdns/dns0.sh
202.101.172.35

这是配置文件片段

• tag: forward_local
  type: fast_forward
  args:
  upstream:
  - addr: ${{ ./dns0.sh }}

这是log

Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: 2021-12-11T18:45:35.015Z info v2/main.go:157 current working directory: /etc/mosdns/
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: 2021-12-11T18:45:35.015Z info v2/main.go:222 mosdns ver: 1171175
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: 2021-12-11T18:45:35.015Z info v2/main.go:223 arch: arm64, os: linux, go: go1.17.3
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: 2021-12-11T18:45:35.015Z info coremain/run.go:65 loading config {"file": "./config.yaml"}
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: panic: runtime error: invalid memory address or nil pointer dereference
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x9a1108]
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]:
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: goroutine 25 [running]:
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/single_flight.(*SingleFlight).Exec(0x0, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210780})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/single_flight/single_flight.go:40 +0x218
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/single_flight.(*SingleFlightPlugin).Exec(0x400006b450, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210780})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/single_flight/single_flight.go:52 +0x54
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).exec(0x40001086c0, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210780})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:104 +0x84
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).Exec(0x40001086c0, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210780})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:88 +0x200
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq.(*RefExecPluginNode).Exec(0x400006bf60, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210780})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq/executable_cmd_sequence.go:45 +0x9c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.ExecChainNode({0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210750})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/utils.go:28 +0x70
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/dual_selector.(*Selector).Exec(0x400000c4b0, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210750})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/dual_selector/dual_selector.go:83 +0xc8
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).exec(0x4000108580, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210750})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:104 +0x84
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).Exec(0x4000108580, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210750})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:88 +0x200
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq.(*RefExecPluginNode).Exec(0x400006bf50, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210750})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq/executable_cmd_sequence.go:45 +0x9c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.ExecChainNode({0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210720})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/utils.go:28 +0x70
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/cache.(*cachePlugin).Exec(0x4000196f00, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210720})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/cache/cache.go:165 +0x41c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).exec(0x4000194200, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210720})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:104 +0x84
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).Exec(0x4000194200, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210720})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:88 +0x200
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq.(*RefExecPluginNode).Exec(0x400006bf40, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x4000210720})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq/executable_cmd_sequence.go:45 +0x9c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.ExecChainNode({0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106f0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/utils.go:28 +0x70
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/ecs.noECS.Exec({0x40001687b0}, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106f0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/plugin/executable/ecs/ecs.go:182 +0x6c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).exec(0x4000108600, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106f0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:104 +0x84
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.(*PluginWrapper).Exec(0x4000108600, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106f0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/plugin_wrapper.go:88 +0x200
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq.(*RefExecPluginNode).Exec(0x400006bf30, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106f0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/executable_seq/executable_cmd_sequence.go:45 +0x9c
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler.ExecChainNode({0xd06008, 0x40002a0000}, 0x40000d0000, {0xd0a9d8, 0x40002106c0})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/handler/utils.go:28 +0x70
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server/dns_handler.(*DefaultHandler).ServeDNS(0x4000109540, {0xd06008, 0x40002a0000}, 0x40000d0000, {0xcf5f40, 0x4000594120})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server/dns_handler/server_handler.go:90 +0x1c4
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server.(*Server).handleQuery(0x4000136790, {0xd05f98, 0x4000194a40}, 0x40000d0000, {0xcf5f40, 0x4000594120})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server/server.go:194 +0xa8
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server.(*Server).startUDP.func1({0xd0df90, 0x4000186448}, {0xd011d0, 0x4000210d50}, 0x40001b6480, 0x4000136790, {0xd05f98, 0x4000194a40})
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server/udp.go:81 +0xfc
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: created by github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server.(*Server).startUDP
Sun Dec 12 02:45:35 2021 daemon.err mosdns[22094]: github.com/IrineSistiana/mosdns/v2/dispatcher/pkg/server/udp.go:74 +0x384

[QiuSimons]

看起来是single_flight挂壁了

[IrineSistiana]

是的。没测试。解决了

[QiuSimons]

是的。没测试。解决了

测试通过，新加的ipv4优先和可执行脚本的设定贼好用

[laggardkernel]

@IrineSistiana 有点问题。我的配置中使用了 vim foldmarker {{{}}}, 直接升级 2.2.0 启动失败报错配置错误。删除 foldmarker 后正常运行。
也有可能是解析 ${{ 时没有忽略注释行？

[IrineSistiana]

解析器比较简单目前还不会忽略注释行.....

[IrineSistiana]

会了

[laggardkernel]

@IrineSistiana 谢谢，2.2.1 测试后正常了。有点不是很清楚，脚本执行者是使用脚本中 shebang 吗？

[IrineSistiana]

我也不清楚。我直接用的 go 自带的包。

[IrineSistiana]

我也不清楚。我直接用的 go 自带的包。