From ef4ec92aab0b5af4774f863d415ef53b9a0e7416 Mon Sep 17 00:00:00 2001
From: Tommaso Pecorella <tommaso.pecorella@unifi.it>
Date: Fri, 18 Aug 2023 18:34:03 +0200
Subject: [PATCH] internet: (fixes #941) fix re-serialization of UDP headers

---
 src/internet/model/udp-header.cc | 7 +++----
 src/internet/model/udp-header.h  | 7 ++++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/internet/model/udp-header.cc b/src/internet/model/udp-header.cc
index 1c7a1052d..3d6c49011 100644
--- a/src/internet/model/udp-header.cc
+++ b/src/internet/model/udp-header.cc
@@ -33,7 +33,6 @@ NS_OBJECT_ENSURE_REGISTERED(UdpHeader);
 UdpHeader::UdpHeader()
     : m_sourcePort(0xfffd),
       m_destinationPort(0xfffd),
-      m_payloadSize(0),
       m_checksum(0),
       m_calcChecksum(false),
       m_goodChecksum(true)
@@ -150,7 +149,7 @@ UdpHeader::ForceChecksum(uint16_t checksum)
 void
 UdpHeader::ForcePayloadSize(uint16_t payloadSize)
 {
-    m_payloadSize = payloadSize;
+    m_forcedPayloadSize = payloadSize;
 }
 
 TypeId
@@ -189,13 +188,13 @@ UdpHeader::Serialize(Buffer::Iterator start) const
 
     i.WriteHtonU16(m_sourcePort);
     i.WriteHtonU16(m_destinationPort);
-    if (m_payloadSize == 0)
+    if (m_forcedPayloadSize == 0)
     {
         i.WriteHtonU16(start.GetSize());
     }
     else
     {
-        i.WriteHtonU16(m_payloadSize);
+        i.WriteHtonU16(m_forcedPayloadSize);
     }
 
     if (m_checksum == 0)
diff --git a/src/internet/model/udp-header.h b/src/internet/model/udp-header.h
index 65a46bae8..43fba6e6a 100644
--- a/src/internet/model/udp-header.h
+++ b/src/internet/model/udp-header.h
@@ -167,9 +167,10 @@ class UdpHeader : public Header
      * \returns the checksum
      */
     uint16_t CalculateHeaderChecksum(uint16_t size) const;
-    uint16_t m_sourcePort;      //!< Source port
-    uint16_t m_destinationPort; //!< Destination port
-    uint16_t m_payloadSize;     //!< Payload size
+    uint16_t m_sourcePort;           //!< Source port
+    uint16_t m_destinationPort;      //!< Destination port
+    uint16_t m_payloadSize{0};       //!< Payload size
+    uint16_t m_forcedPayloadSize{0}; //!< Payload size (forced)
 
     Address m_source;      //!< Source IP address
     Address m_destination; //!< Destination IP address