From 92bfb95bcf5b7f4d9dfad85f198e493eb5b84a6b Mon Sep 17 00:00:00 2001
From: karl <karl@bear.com>
Date: Thu, 2 Jan 2025 19:41:31 +0800
Subject: [PATCH] =?UTF-8?q?DNS=E8=A7=A3=E6=9E=90=E6=97=B6=EF=BC=8CTCP=20?=
 =?UTF-8?q?=E4=BB=8E=E5=93=AA=E4=B8=AA=20IP=20=E8=BF=9B=E6=9D=A5=EF=BC=8C?=
 =?UTF-8?q?=E5=B0=B1=E4=BB=8E=E5=93=AA=E4=B8=AA=20IP=20=E8=A7=A3=E6=9E=90?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 chain.go | 7 +++++++
 dns.go   | 6 +++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/chain.go b/chain.go
index f98b781..59b0c95 100644
--- a/chain.go
+++ b/chain.go
@@ -212,6 +212,13 @@ func (c *Chain) dialWithOptions(ctx context.Context, network, address string, op
 					IP: ip,
 				}
 			}
+		} else if inboundIP != nil && strings.ToLower(network) == "udp" {
+			ip := inboundIP.(net.IP)
+			if !ip.IsLoopback() && !ip.IsPrivate() {
+				d.LocalAddr = &net.UDPAddr{
+					IP: ip,
+				}
+			}
 		}
 		return d.DialContext(ctx, network, ipAddr)
 	}
diff --git a/dns.go b/dns.go
index 1b02404..6575846 100644
--- a/dns.go
+++ b/dns.go
@@ -83,7 +83,11 @@ func (h *dnsHandler) Handle(conn net.Conn) {
 	if resolver == nil {
 		resolver = defaultResolver
 	}
-	reply, err := resolver.Exchange(context.Background(), b[:n])
+	ctx := context.Background()
+	if inboundAddr, ok := conn.LocalAddr().(*net.TCPAddr); ok {
+		ctx = context.WithValue(ctx, "InboundIP", inboundAddr.IP)
+	}
+	reply, err := resolver.Exchange(ctx, b[:n])
 	if err != nil {
 		log.Logf("[dns] %s - %s exchange: %v", conn.RemoteAddr(), conn.LocalAddr(), err)
 		return