From c797eaa9f818a36b57add06497ff465b1263708c Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 11 Feb 2022 12:38:10 +0100
Subject: [PATCH] Kernel/Net: Don't update TCP socket "last sent ACK" field too
 early

Defer updating this field until after the last fallible operation has
succeeded.
---
 Kernel/Net/TCPSocket.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Kernel/Net/TCPSocket.cpp b/Kernel/Net/TCPSocket.cpp
index 86143a8b526..2fe8161a415 100644
--- a/Kernel/Net/TCPSocket.cpp
+++ b/Kernel/Net/TCPSocket.cpp
@@ -237,12 +237,6 @@ ErrorOr<void> TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* pa
     tcp_packet.set_data_offset(tcp_header_size / sizeof(u32));
     tcp_packet.set_flags(flags);
 
-    if (flags & TCPFlags::ACK) {
-        m_last_ack_number_sent = m_ack_number;
-        m_last_ack_sent_time = kgettimeofday();
-        tcp_packet.set_ack_number(m_ack_number);
-    }
-
     if (payload) {
         if (auto result = payload->read(tcp_packet.payload(), payload_size); result.is_error()) {
             routing_decision.adapter->release_packet_buffer(*packet);
@@ -250,6 +244,12 @@ ErrorOr<void> TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* pa
         }
     }
 
+    if (flags & TCPFlags::ACK) {
+        m_last_ack_number_sent = m_ack_number;
+        m_last_ack_sent_time = kgettimeofday();
+        tcp_packet.set_ack_number(m_ack_number);
+    }
+
     if (flags & TCPFlags::SYN) {
         ++m_sequence_number;
     } else {