From 257188b5e94687b63391602b532b08a4a9681a5d Mon Sep 17 00:00:00 2001
From: kangping <wgtdkp@google.com>
Date: Thu, 29 Apr 2021 22:50:19 +0800
Subject: [PATCH] [tmf] avoid binding TMF port for user UDP (#6534)

---
 src/core/net/udp6.cpp | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/core/net/udp6.cpp b/src/core/net/udp6.cpp
index bd2584ebc..b16f4bd46 100644
--- a/src/core/net/udp6.cpp
+++ b/src/core/net/udp6.cpp
@@ -409,14 +409,17 @@ uint16_t Udp::GetEphemeralPort(void)
 {
     uint16_t rval = mEphemeralPort;
 
-    if (mEphemeralPort < kDynamicPortMax)
+    do
     {
-        mEphemeralPort++;
-    }
-    else
-    {
-        mEphemeralPort = kDynamicPortMin;
-    }
+        if (mEphemeralPort < kDynamicPortMax)
+        {
+            mEphemeralPort++;
+        }
+        else
+        {
+            mEphemeralPort = kDynamicPortMin;
+        }
+    } while (rval == Tmf::kUdpPort);
 
     return rval;
 }