From e58b7343632f8b5bb0e03a436d9db5872084d236 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sun, 4 Aug 2019 21:22:22 +0200
Subject: [PATCH] Net: Use KBuffers for network adapter packet queues

This further reduces pressure on the kmalloc heap. :^)
---
 Kernel/Net/NetworkAdapter.cpp |  4 ++--
 Kernel/Net/NetworkAdapter.h   |  5 +++--
 Kernel/Net/NetworkTask.cpp    | 11 ++++++-----
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Kernel/Net/NetworkAdapter.cpp b/Kernel/Net/NetworkAdapter.cpp
index f4ef012c4f..6476305daa 100644
--- a/Kernel/Net/NetworkAdapter.cpp
+++ b/Kernel/Net/NetworkAdapter.cpp
@@ -81,10 +81,10 @@ void NetworkAdapter::send_ipv4(const MACAddress& destination_mac, const IPv4Addr
 void NetworkAdapter::did_receive(const u8* data, int length)
 {
     InterruptDisabler disabler;
-    m_packet_queue.append(ByteBuffer::copy(data, length));
+    m_packet_queue.append(KBuffer::copy(data, length));
 }
 
-ByteBuffer NetworkAdapter::dequeue_packet()
+RefPtr<KBuffer> NetworkAdapter::dequeue_packet()
 {
     InterruptDisabler disabler;
     if (m_packet_queue.is_empty())
diff --git a/Kernel/Net/NetworkAdapter.h b/Kernel/Net/NetworkAdapter.h
index 2052b3cc43..d2b4c10862 100644
--- a/Kernel/Net/NetworkAdapter.h
+++ b/Kernel/Net/NetworkAdapter.h
@@ -4,6 +4,7 @@
 #include <AK/Function.h>
 #include <AK/SinglyLinkedList.h>
 #include <AK/Types.h>
+#include <Kernel/KBuffer.h>
 #include <Kernel/Net/ARP.h>
 #include <Kernel/Net/ICMP.h>
 #include <Kernel/Net/IPv4.h>
@@ -28,7 +29,7 @@ public:
     void send(const MACAddress&, const ARPPacket&);
     void send_ipv4(const MACAddress&, const IPv4Address&, IPv4Protocol, ByteBuffer&& payload);
 
-    ByteBuffer dequeue_packet();
+    RefPtr<KBuffer> dequeue_packet();
 
     bool has_queued_packets() const { return !m_packet_queue.is_empty(); }
 
@@ -42,6 +43,6 @@ protected:
 private:
     MACAddress m_mac_address;
     IPv4Address m_ipv4_address;
-    SinglyLinkedList<ByteBuffer> m_packet_queue;
+    SinglyLinkedList<NonnullRefPtr<KBuffer>> m_packet_queue;
     String m_name;
 };
diff --git a/Kernel/Net/NetworkTask.cpp b/Kernel/Net/NetworkTask.cpp
index cb23144a44..4ff8b1c9bd 100644
--- a/Kernel/Net/NetworkTask.cpp
+++ b/Kernel/Net/NetworkTask.cpp
@@ -44,10 +44,10 @@ void NetworkTask_main()
     if (adapter)
         adapter->set_ipv4_address(IPv4Address(192, 168, 5, 2));
 
-    auto dequeue_packet = [&]() -> ByteBuffer {
+    auto dequeue_packet = [&]() -> RefPtr<KBuffer> {
         auto packet = LoopbackAdapter::the().dequeue_packet();
         if (!packet.is_null()) {
-            dbgprintf("Receive loopback packet (%d bytes)\n", packet.size());
+            dbgprintf("Receive loopback packet (%d bytes)\n", packet->size());
             return packet;
         }
         if (adapter && adapter->has_queued_packets())
@@ -57,8 +57,8 @@ void NetworkTask_main()
 
     kprintf("NetworkTask: Enter main loop.\n");
     for (;;) {
-        auto packet = dequeue_packet();
-        if (packet.is_null()) {
+        auto packet_maybe_null = dequeue_packet();
+        if (packet_maybe_null.is_null()) {
             (void)current->block_until("Networking", [] {
                 if (LoopbackAdapter::the().has_queued_packets())
                     return true;
@@ -70,11 +70,12 @@ void NetworkTask_main()
             });
             continue;
         }
+        auto& packet = *packet_maybe_null;
         if (packet.size() < (int)(sizeof(EthernetFrameHeader))) {
             kprintf("NetworkTask: Packet is too small to be an Ethernet packet! (%d)\n", packet.size());
             continue;
         }
-        auto& eth = *(const EthernetFrameHeader*)packet.pointer();
+        auto& eth = *(const EthernetFrameHeader*)packet.data();
 #ifdef ETHERNET_DEBUG
         kprintf("NetworkTask: From %s to %s, ether_type=%w, packet_length=%u\n",
             eth.source().to_string().characters(),