TCP: Collect the payload if present in a packet with FIN set.

Kernel/IPv4Socket.cpp

@@ -222,9 +222,11 @@ ssize_t IPv4Socket::recvfrom(void* buffer, size_t buffer_length, int flags, sock
 void IPv4Socket::did_receive(ByteBuffer&& packet)
 {
     LOCKER(lock());
+    auto packet_size = packet.size();
     m_receive_queue.append(move(packet));
     m_can_read = true;
+    m_bytes_received += packet_size;
 #ifdef IPV4_SOCKET_DEBUG
-    kprintf("IPv4Socket(%p): did_receive %d bytes, packets in queue: %d\n", this, packet.size(), m_receive_queue.size_slow());
+    kprintf("IPv4Socket(%p): did_receive %d bytes, total_received=%u, packets in queue: %d\n", this, packet_size, m_bytes_received, m_receive_queue.size_slow());
 #endif
 }

Kernel/IPv4Socket.h

@@ -68,6 +68,8 @@ private:
     word m_source_port { 0 };
     word m_destination_port { 0 };
 
+    dword m_bytes_received { 0 };
+
     bool m_can_read { false };
 };
 

Kernel/NetworkTask.cpp

@@ -302,6 +302,10 @@ void handle_tcp(const EthernetFrameHeader& eth, int frame_size)
 
     if (tcp_packet.has_fin()) {
         kprintf("handle_tcp: Got FIN, payload_size=%u\n", payload_size);
+
+        if (payload_size != 0)
+            socket->did_receive(ByteBuffer::copy((const byte*)&ipv4_packet, sizeof(IPv4Packet) + ipv4_packet.payload_size()));
+
         socket->set_ack_number(tcp_packet.sequence_number() + payload_size + 1);
         socket->send_tcp_packet(TCPFlags::FIN | TCPFlags::ACK);
         socket->set_state(TCPSocket::State::Disconnecting);