dhcpd: check server existence on more platforms

2025-02-22 17:05:42 +08:00 · 2022-02-23 17:48:43 +08:00 · 2022-02-23 17:48:43 +08:00 · 1f196c9cf5
commit 1f196c9cf5
parent f96ad73c7d
12 changed files with 144 additions and 86 deletions
--- a/README.md
+++ b/README.md
@ -84,8 +84,6 @@ we can set up local listeners as proxy servers, and forward requests to internet

 ## Usage

-**Run:**
-
 ```bash
 glider -config CONFIG_PATH
 ```
@ -93,10 +91,10 @@ glider -config CONFIG_PATH
 glider -verbose -listen :8443 -forward SCHEME://HOST:PORT
 ```

-**Help:**
+#### Help

 <details>
-<summary>`glider -help` click to see details</summary>
+<summary>`glider -help` (click to see details)</summary>

 ```bash
 Usage: glider [-listen URL]... [-forward URL]... [OPTION]...
@ -224,10 +222,10 @@ glider 0.16.0, https://github.com/nadoo/glider

 </details>

-**Schemes:**
+#### Schemes

 <details>
-<summary>`glider -scheme all` click to see details</summary>
+<summary>`glider -scheme all` (click to see details)</summary>

 ```bash
 KCP scheme:
@ -339,39 +337,42 @@ TLS and Websocket with a specified proxy protocol:

 </details>

-**Examples:**
+#### Examples

 <details>
-<summary>`glider -example` click to see details</summary>
+<summary>`glider -example` (click to see details)</summary>

 ```bash
 Examples:
  glider -config glider.conf
    -run glider with specified config file.
-
+  
  glider -listen :8443 -verbose
    -listen on :8443, serve as http/socks5 proxy on the same port, in verbose mode.

+  glider -listen socks5://:1080 -listen http://:8080 -verbose
+    -multiple listeners: listen on :1080 as socks5 proxy server, and on :8080 as http proxy server.
+  
  glider -listen :8443 -forward direct://#interface=eth0 -forward direct://#interface=eth1
-    -listen on 8443 and forward requests via interface eth0 and eth1 in round robin mode.
-
+    -multiple forwarders: listen on 8443 and forward requests via interface eth0 and eth1 in round robin mode.
+  
  glider -listen tls://:443?cert=crtFilePath&key=keyFilePath,http:// -verbose
-    -listen on :443 as a https(http over tls) proxy server.
-
+    -protocol chain: listen on :443 as a https(http over tls) proxy server.
+  
  glider -listen http://:8080 -forward socks5://serverA:1080,socks5://serverB:1080
-    -listen on :8080 as a http proxy server, forward all requests via forward chain.
-
+    -proxy chain: listen on :8080 as a http proxy server, forward all requests via forward chain.
+  
  glider -listen :8443 -forward socks5://serverA:1080 -forward socks5://serverB:1080#priority=10 -forward socks5://serverC:1080#priority=10
-    -serverA will only be used when serverB and serverC are not available.
-
+    -forwarder priority: serverA will only be used when serverB and serverC are not available.
+  
  glider -listen tcp://:80 -forward tcp://serverA:80
    -tcp tunnel: listen on :80 and forward all requests to serverA:80.
-
+  
  glider -listen udp://:53 -forward socks5://serverA:1080,udp://8.8.8.8:53
-    -listen on :53 and forward all udp requests to 8.8.8.8:53 via remote socks5 server.
-
-  glider -verbose -listen -dns=:53 -dnsserver=8.8.8.8:53 -forward socks5://serverA:1080 -dnsrecord=www.example.com/1.2.3.4
-    -listen on :53 as dns server, forward to 8.8.8.8:53 via socks5 server.
+    -udp tunnel: listen on :53 and forward all udp requests to 8.8.8.8:53 via remote socks5 server.
+  
+  glider -verbose -listen -dns=:53 -dnsserver=8.8.8.8:53 -forward socks5://serverA:1080 -dnsrecord=abc.com/1.2.3.4
+    -dns over proxy: listen on :53 as dns server, forward to 8.8.8.8:53 via socks5 server.
 ```

 </details>
--- a/config.go
+++ b/config.go
@ -224,25 +224,28 @@ Examples:
  
  glider -listen :8443 -verbose
    -listen on :8443, serve as http/socks5 proxy on the same port, in verbose mode.
+
+  glider -listen socks5://:1080 -listen http://:8080 -verbose
+    -multiple listeners: listen on :1080 as socks5 proxy server, and on :8080 as http proxy server.
  
  glider -listen :8443 -forward direct://#interface=eth0 -forward direct://#interface=eth1
-    -listen on 8443 and forward requests via interface eth0 and eth1 in round robin mode.
+    -multiple forwarders: listen on 8443 and forward requests via interface eth0 and eth1 in round robin mode.
  
  glider -listen tls://:443?cert=crtFilePath&key=keyFilePath,http:// -verbose
-    -listen on :443 as a https(http over tls) proxy server.
+    -protocol chain: listen on :443 as a https(http over tls) proxy server.
  
  glider -listen http://:8080 -forward socks5://serverA:1080,socks5://serverB:1080
-    -listen on :8080 as a http proxy server, forward all requests via forward chain.
+    -proxy chain: listen on :8080 as a http proxy server, forward all requests via forward chain.
  
  glider -listen :8443 -forward socks5://serverA:1080 -forward socks5://serverB:1080#priority=10 -forward socks5://serverC:1080#priority=10
-    -serverA will only be used when serverB and serverC are not available.
+    -forwarder priority: serverA will only be used when serverB and serverC are not available.
  
  glider -listen tcp://:80 -forward tcp://serverA:80
    -tcp tunnel: listen on :80 and forward all requests to serverA:80.
  
  glider -listen udp://:53 -forward socks5://serverA:1080,udp://8.8.8.8:53
-    -listen on :53 and forward all udp requests to 8.8.8.8:53 via remote socks5 server.
+    -udp tunnel: listen on :53 and forward all udp requests to 8.8.8.8:53 via remote socks5 server.
  
-  glider -verbose -listen -dns=:53 -dnsserver=8.8.8.8:53 -forward socks5://serverA:1080 -dnsrecord=www.example.com/1.2.3.4
-    -listen on :53 as dns server, forward to 8.8.8.8:53 via socks5 server.
+  glider -verbose -listen -dns=:53 -dnsserver=8.8.8.8:53 -forward socks5://serverA:1080 -dnsrecord=abc.com/1.2.3.4
+    -dns over proxy: listen on :53 as dns server, forward to 8.8.8.8:53 via socks5 server.
 `
--- a/go.mod
+++ b/go.mod
@ -12,15 +12,15 @@ require (
 	github.com/nadoo/ipset v0.4.1-0.20220218075046-ca3cdce74266
 	github.com/xtaci/kcp-go/v5 v5.6.1
 	golang.org/x/crypto v0.0.0-20220214200702-86341886e292
-	golang.org/x/sys v0.0.0-20220209214540-3681064d5158
+	golang.org/x/sys v0.0.0-20220222200937-f2425489ef4c
 )

 require (
 	github.com/ebfe/rc2 v0.0.0-20131011165748-24b9757f5521 // indirect
 	github.com/klauspost/cpuid/v2 v2.0.11 // indirect
 	github.com/klauspost/reedsolomon v1.9.16 // indirect
-	github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 // indirect
-	github.com/mdlayher/raw v0.0.0-20211126142749-4eae47f3d54b // indirect
+	github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118 // indirect
+	github.com/mdlayher/raw v0.1.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/templexxx/cpu v0.0.10-0.20211111114238-98168dcec14a // indirect
 	github.com/templexxx/xorsimd v0.4.1 // indirect
--- a/go.sum
+++ b/go.sum
@ -34,13 +34,15 @@ github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5a
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
-github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 h1:/jC7qQFrv8CrSJVmaolDVOxTfS9kc36uB6H40kdbQq8=
 github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
 github.com/insomniacslk/dhcp v0.0.0-20220119180841-3c283ff8b7dd h1:efcJu2Vzz6DoSq245deWNzTz6l/gsqdphm3FjmI88/g=
 github.com/insomniacslk/dhcp v0.0.0-20220119180841-3c283ff8b7dd/go.mod h1:h+MxyHxRg9NH3terB1nfRIUaQEcI0XOVkdR9LNBlp8E=
+github.com/josharian/native v1.0.0 h1:Ts/E8zCSEsG17dUqv7joXJFybuMLjQfWE04tsBODTxk=
+github.com/josharian/native v1.0.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
 github.com/jsimonetti/rtnetlink v0.0.0-20190606172950-9527aa82566a/go.mod h1:Oz+70psSo5OFh8DBl0Zv2ACw7Esh6pPUphlvZG9x7uw=
 github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4/go.mod h1:WGuG/smIU4J/54PblvSbh+xvCZmpJnFgr3ds6Z55XMQ=
 github.com/jsimonetti/rtnetlink v0.0.0-20201009170750-9c6f07d100c1/go.mod h1:hqoO/u39cqLeBLebZ8fWdE96O7FxrAsRYhnVOdgHxok=
@ -54,16 +56,21 @@ github.com/klauspost/cpuid/v2 v2.0.11/go.mod h1:g2LTdtYhdyuGPqyWyv7qRAmj1WBqxuOb
 github.com/klauspost/reedsolomon v1.9.9/go.mod h1:O7yFFHiQwDR6b2t63KPUpccPtNdp5ADgh1gg4fd12wo=
 github.com/klauspost/reedsolomon v1.9.16 h1:mR0AwphBwqFv/I3B9AHtNKvzuowI1vrj8/3UX4XRmHA=
 github.com/klauspost/reedsolomon v1.9.16/go.mod h1:eqPAcE7xar5CIzcdfwydOEdcmchAKAP/qs14y4GCBOk=
-github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 h1:lez6TS6aAau+8wXUP3G9I3TGlmPFEq2CTxBaRqY6AGE=
 github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7/go.mod h1:U6ZQobyTjI/tJyq2HG+i/dfSoFUt8/aZCM+GKtmFk/Y=
+github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118 h1:2oDp6OOhLxQ9JBoUuysVz9UZ9uI6oLUbvAZu0x8o+vE=
+github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118/go.mod h1:ZFUnHIVchZ9lJoWoEGUg8Q3M4U8aNNWA3CVSUTkW4og=
 github.com/mdlayher/netlink v0.0.0-20190409211403-11939a169225/go.mod h1:eQB3mZE4aiYnlUsyGGCOpPETfdQq4Jhsgf1fk3cwQaA=
 github.com/mdlayher/netlink v1.0.0/go.mod h1:KxeJAFOFLG6AjpyDkQ/iIhxygIUKD+vcwqcnu43w/+M=
 github.com/mdlayher/netlink v1.1.0/go.mod h1:H4WCitaheIsdF9yOYu8CFmCgQthAPIWZmcKp9uZHgmY=
 github.com/mdlayher/netlink v1.1.1/go.mod h1:WTYpFb/WTvlRJAyKhZL5/uy69TDDpHHu2VZmb2XgV7o=
+github.com/mdlayher/packet v1.0.0 h1:InhZJbdShQYt6XV2GPj5XHxChzOfhJJOMbvnGAmOfQ8=
+github.com/mdlayher/packet v1.0.0/go.mod h1:eE7/ctqDhoiRhQ44ko5JZU2zxB88g+JH/6jmnjzPjOU=
 github.com/mdlayher/raw v0.0.0-20190606142536-fef19f00fc18/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
 github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
-github.com/mdlayher/raw v0.0.0-20211126142749-4eae47f3d54b h1:MHcTarUMC4sFA7eiyR8IEJ6j2PgmgXR+B9X2IIMjh7A=
-github.com/mdlayher/raw v0.0.0-20211126142749-4eae47f3d54b/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
+github.com/mdlayher/raw v0.1.0 h1:K4PFMVy+AFsp0Zdlrts7yNhxc/uXoPVHi9RzRvtZF2Y=
+github.com/mdlayher/raw v0.1.0/go.mod h1:yXnxvs6c0XoF/aK52/H5PjsVHmWBCFfZUfoh/Y5s9Sg=
+github.com/mdlayher/socket v0.2.1 h1:F2aaOwb53VsBE+ebRS9bLd7yPOfYUMC8lOODdCBDY6w=
+github.com/mdlayher/socket v0.2.1/go.mod h1:QLlNPkFR88mRUNQIzRBMfXxwKal8H7u1h3bL1CV+f0E=
 github.com/mmcloughlin/avo v0.0.0-20200803215136-443f81d77104/go.mod h1:wqKykBG2QzQDJEzvRkcS8x6MiSJkF52hXZsXcjaB3ls=
 github.com/nadoo/conflag v0.3.1 h1:4pHkLIz8PUsfg6ajNYRRSY3bt6m2LPsu6KOzn5uIXQw=
 github.com/nadoo/conflag v0.3.1/go.mod h1:dzFfDUpXdr2uS2oV+udpy5N2vfNOu/bFzjhX1WI52co=
@ -118,6 +125,7 @@ golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190419010253-1f3472d942ba/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190827160401-ba9fcec4b297/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@ -136,6 +144,8 @@ golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@ -152,8 +162,10 @@ golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201101102859-da207088b7d1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220209214540-3681064d5158 h1:rm+CHSpPEEW2IsXUib1ThaHIjuBVZjxNgSKmBLFfD4c=
+golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220222200937-f2425489ef4c h1:sSIdNI2Dd6vGv47bKc/xArpfxVmEz2+3j0E6I484xC4=
+golang.org/x/sys v0.0.0-20220222200937-f2425489ef4c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
--- a/pkg/sockopt/bind_darwin.go
+++ b/pkg/sockopt/bind_darwin.go
@ -0,0 +1,21 @@
+package sockopt
+
+import (
+	"net"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func BindControl(iface *net.Interface) func(network, address string, c syscall.RawConn) error {
+	return func(network, address string, c syscall.RawConn) (err error) {
+		return c.Control(func(fd uintptr) {
+			switch network {
+			case "tcp4", "udp4":
+				err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_BOUND_IF, iface.Index)
+			case "tcp6", "udp6":
+				err = unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_BOUND_IF, iface.Index)
+			}
+		})
+	}
+}
--- a/pkg/sockopt/bind_linux.go
+++ b/pkg/sockopt/bind_linux.go
@ -8,9 +8,9 @@ import (
 )

 func BindControl(iface *net.Interface) func(network, address string, c syscall.RawConn) error {
-	return func(network, address string, c syscall.RawConn) error {
+	return func(network, address string, c syscall.RawConn) (err error) {
 		return c.Control(func(fd uintptr) {
-			unix.BindToDevice(int(fd), iface.Name)
+			err = unix.BindToDevice(int(fd), iface.Name)
 		})
 	}
 }
--- a/pkg/sockopt/bind_others.go
+++ b/pkg/sockopt/bind_others.go
@ -1,5 +1,5 @@
-//go:build !linux
-// +build !linux
+//go:build !linux && !darwin
+// +build !linux,!darwin

 package sockopt

--- a/rule/group.go
+++ b/rule/group.go
@ -267,8 +267,8 @@ func (p *FwdrGroup) check(fwdr *Forwarder, checker Checker) {

 		wait = 1
 		p.setLatency(fwdr, elapsed)
-		log.F("[check] %s: %s(%d), SUCCESS. elapsed: %s, Latency: %s",
-			p.name, fwdr.Addr(), fwdr.Priority(), elapsed, time.Duration(fwdr.Latency()))
+		log.F("[check] %s: %s(%d), SUCCESS. Elapsed: %dms, Latency: %dms.",
+			p.name, fwdr.Addr(), fwdr.Priority(), elapsed.Milliseconds(), time.Duration(fwdr.Latency()).Milliseconds())
 		fwdr.Enable()
 	}
 }
--- a/service/dhcpd/cilent.go
+++ b/service/dhcpd/cilent.go
@ -0,0 +1,56 @@
+package dhcpd
+
+import (
+	"context"
+	"net"
+	"runtime"
+	"time"
+
+	"github.com/insomniacslk/dhcp/dhcpv4"
+
+	"github.com/nadoo/glider/pkg/log"
+	"github.com/nadoo/glider/pkg/sockopt"
+)
+
+func existsServer(intf *net.Interface) (exists bool) {
+	lc := &net.ListenConfig{}
+	lc.Control = sockopt.BindControl(intf)
+
+	addr := "0.0.0.0:68"
+	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
+		addr = "255.255.255.255:68"
+	}
+
+	pc, err := lc.ListenPacket(context.Background(), "udp4", addr)
+	if err != nil {
+		log.F("[dhcpd] failed in dhcp client ListenPacket: %s", err)
+		return
+	}
+	defer pc.Close()
+
+	discovery, err := dhcpv4.NewDiscovery(intf.HardwareAddr, dhcpv4.WithBroadcast(true))
+	if err != nil {
+		log.F("[dhcpd] failed in dhcp client NewDiscovery: %s", err)
+		return
+	}
+
+	_, err = pc.WriteTo(discovery.ToBytes(), &net.UDPAddr{IP: net.IPv4bcast, Port: 67})
+	if err != nil {
+		log.F("[dhcpd] failed in dhcp client WriteTo: %s", err)
+		return
+	}
+
+	var buf [dhcpv4.MaxMessageSize]byte
+	pc.SetReadDeadline(time.Now().Add(time.Second * 3))
+	n, _, err := pc.ReadFrom(buf[:])
+	if err != nil {
+		return
+	}
+
+	msg, err := dhcpv4.FromBytes(buf[:n])
+	if err != nil || msg.TransactionID != discovery.TransactionID {
+		return
+	}
+
+	return true
+}
--- a/service/dhcpd/cilent_linux.go
+++ b/service/dhcpd/cilent_linux.go
@ -1,27 +0,0 @@
-package dhcpd
-
-import (
-	"context"
-	"time"
-
-	"github.com/insomniacslk/dhcp/dhcpv4/nclient4"
-
-	"github.com/nadoo/glider/pkg/log"
-)
-
-func existsServer(iface string) (exists bool) {
-	client, err := nclient4.New(iface)
-	if err != nil {
-		log.F("[dhcpd] failed in dhcp client creation: %s", err)
-		return
-	}
-	defer client.Close()
-
-	ctx, _ := context.WithTimeout(context.Background(), 3*time.Second)
-	_, err = client.Request(ctx)
-	if err != nil {
-		return
-	}
-
-	return true
-}
--- a/service/dhcpd/client_others.go
+++ b/service/dhcpd/client_others.go
@ -1,8 +0,0 @@
-//go:build !linux
-// +build !linux
-
-package dhcpd
-
-func existsServer(iface string) (exists bool) {
-	return false
-}
--- a/service/dhcpd/dhcpd.go
+++ b/service/dhcpd/dhcpd.go
@ -35,13 +35,13 @@ func (*dpcpd) Run(args ...string) {
 		leaseTime = time.Duration(i) * time.Minute
 	}

-	ip, mask, _, err := ifaceAddr(iface)
+	intf, ip, mask, err := ifaceAddr(iface)
 	if err != nil {
 		log.F("[dhcpd] get ip of interface '%s' error: %s", iface, err)
 		return
 	}

-	if existsServer(iface) {
+	if existsServer(intf) {
 		log.F("[dhcpd] found existing dhcp server on interface %s, service exiting", iface)
 		return
 	}
@ -146,7 +146,7 @@ func handleDHCP(serverIP net.IP, mask net.IPMask, pool *Pool) server4.Handler {
 	}
 }

-func ifaceAddr(iface string) (net.IP, net.IPMask, net.HardwareAddr, error) {
+func ifaceAddr(iface string) (*net.Interface, net.IP, net.IPMask, error) {
 	intf, err := net.InterfaceByName(iface)
 	if err != nil {
 		return nil, nil, nil, err
@ -154,19 +154,19 @@ func ifaceAddr(iface string) (net.IP, net.IPMask, net.HardwareAddr, error) {

 	addrs, err := intf.Addrs()
 	if err != nil {
-		return nil, nil, intf.HardwareAddr, err
+		return intf, nil, nil, err
 	}

 	for _, addr := range addrs {
 		if ipnet, ok := addr.(*net.IPNet); ok {
 			if ipnet.IP.IsLoopback() {
-				return nil, nil, intf.HardwareAddr, errors.New("can't use loopback interface")
+				return intf, nil, nil, errors.New("can't use loopback interface")
 			}
 			if ip4 := ipnet.IP.To4(); ip4 != nil {
-				return ip4, ipnet.Mask, intf.HardwareAddr, nil
+				return intf, ip4, ipnet.Mask, nil
 			}
 		}
 	}

-	return nil, nil, intf.HardwareAddr, errors.New("no ip/mask defined on this interface")
+	return intf, nil, nil, errors.New("no ip/mask defined on this interface")
 }