From b06ba191b2e7eaca2d762ce7da9f494e43634dcf Mon Sep 17 00:00:00 2001
From: nmreadelf <frank.q.kong@hotmail.com>
Date: Thu, 17 Aug 2023 10:27:28 +0800
Subject: [PATCH] Judge client id in dhcpv4

---
 go.mod                    | 7 +++++--
 internal/dhcpd/v4_unix.go | 6 ++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/go.mod b/go.mod
index d4ba483c641..a98c03ee721 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,6 @@ require (
 	github.com/ameshkov/dnscrypt/v2 v2.2.7
 	github.com/bluele/gcache v0.0.2
 	github.com/digineo/go-ipset/v2 v2.2.1
-	github.com/dimfeld/httptreemux/v5 v5.5.0
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/go-ping/ping v1.1.0
 	github.com/google/go-cmp v0.5.9
@@ -40,6 +39,11 @@ require (
 	howett.net/plist v1.0.0
 )
 
+require (
+	github.com/dimfeld/httptreemux/v5 v5.5.0
+	github.com/u-root/uio v0.0.0-20230305220412-3e8cd9d6bf63
+)
+
 require (
 	github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da // indirect
 	github.com/aead/poly1305 v0.0.0-20180717145839-3fee0db0b635 // indirect
@@ -57,7 +61,6 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/quic-go/qpack v0.4.0 // indirect
 	github.com/quic-go/qtls-go1-20 v0.3.2 // indirect
-	github.com/u-root/uio v0.0.0-20230305220412-3e8cd9d6bf63 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/sync v0.3.0 // indirect
 	golang.org/x/text v0.12.0 // indirect
diff --git a/internal/dhcpd/v4_unix.go b/internal/dhcpd/v4_unix.go
index 6a973b24f7b..e6d84a70238 100644
--- a/internal/dhcpd/v4_unix.go
+++ b/internal/dhcpd/v4_unix.go
@@ -20,6 +20,7 @@ import (
 	"github.com/go-ping/ping"
 	"github.com/insomniacslk/dhcp/dhcpv4"
 	"github.com/insomniacslk/dhcp/dhcpv4/server4"
+	"github.com/u-root/uio/uio"
 	"golang.org/x/exp/slices"
 )
 
@@ -1162,6 +1163,11 @@ func (s *v4Server) packetHandler(conn net.PacketConn, peer net.Addr, req *dhcpv4
 
 		return
 	}
+	if opt := req.Options.Get(dhcpv4.OptionClientIdentifier); opt != nil {
+		buf := uio.NewBigEndianBuffer(opt)
+		_ = buf.Read8()
+		buf.ReadBytes(req.ClientHWAddr)
+	}
 
 	err = netutil.ValidateMAC(req.ClientHWAddr)
 	if err != nil {