Kernel+LibC: Add support for the IPv4 TOS field via the IP_TOS sockopt

Kernel/API/POSIX/netinet/in.h

@@ -22,6 +22,7 @@ typedef uint32_t in_addr_t;
 
 #define IN_LOOPBACKNET 127
 
+#define IP_TOS 1
 #define IP_TTL 2
 #define IP_MULTICAST_LOOP 3
 #define IP_ADD_MEMBERSHIP 4
@@ -29,6 +30,10 @@ typedef uint32_t in_addr_t;
 #define IP_MULTICAST_IF 6
 #define IP_MULTICAST_TTL 7
 
+#define IPTOS_LOWDELAY 16
+#define IPTOS_THROUGHPUT 8
+#define IPTOS_RELIABILITY 4
+
 /* Make sure these don't overlap with any other IPv4 and IPv6 options */
 #define MCAST_JOIN_SOURCE_GROUP 100
 #define MCAST_LEAVE_SOURCE_GROUP 101

Kernel/Net/IPv4.h

@@ -32,6 +32,9 @@ public:
     u8 version() const { return (m_version_and_ihl >> 4) & 0xf; }
     void set_version(u8 version) { m_version_and_ihl = (m_version_and_ihl & 0x0f) | (version << 4); }
 
+    u8 dscp_and_ecn() const { return m_dscp_and_ecn; }
+    void set_dscp_and_ecn(u8 dscp_and_ecn) { m_dscp_and_ecn = dscp_and_ecn; }
+
     u8 internet_header_length() const { return m_version_and_ihl & 0xf; }
     void set_internet_header_length(u8 ihl) { m_version_and_ihl = (m_version_and_ihl & 0xf0) | (ihl & 0x0f); }
 

Kernel/Net/IPv4Socket.cpp

@@ -229,7 +229,7 @@ KResultOr<size_t> IPv4Socket::sendto(OpenFileDescription&, const UserOrKernelBuf
         if (!packet)
             return set_so_error(ENOMEM);
         routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(), routing_decision.next_hop,
-            m_peer_address, (IPv4Protocol)protocol(), data_length, m_ttl);
+            m_peer_address, (IPv4Protocol)protocol(), data_length, m_type_of_service, m_ttl);
         if (auto result = data.read(packet->buffer->data() + ipv4_payload_offset, data_length); result.is_error()) {
             routing_decision.adapter->release_packet_buffer(*packet);
             return set_so_error(result);
@@ -504,6 +504,16 @@ KResult IPv4Socket::setsockopt(int level, int option, Userspace<const void*> use
         m_ttl = value;
         return KSuccess;
     }
+    case IP_TOS: {
+        if (user_value_size < sizeof(int))
+            return EINVAL;
+        int value;
+        TRY(copy_from_user(&value, static_ptr_cast<const int*>(user_value)));
+        if (value < 0 || value > 255)
+            return EINVAL;
+        m_type_of_service = value;
+        return KSuccess;
+    }
     case IP_MULTICAST_LOOP: {
         if (user_value_size != 1)
             return EINVAL;
@@ -559,6 +569,14 @@ KResult IPv4Socket::getsockopt(OpenFileDescription& description, int level, int
         size = sizeof(int);
         return copy_to_user(value_size, &size);
     }
+    case IP_TOS: {
+        if (size < sizeof(int))
+            return EINVAL;
+        int type_of_service = m_type_of_service;
+        TRY(copy_to_user(static_ptr_cast<int*>(value), (int*)&type_of_service));
+        size = sizeof(int);
+        return copy_to_user(value_size, &size);
+    }
     case IP_MULTICAST_LOOP: {
         if (size < 1)
             return EINVAL;

Kernel/Net/IPv4Socket.h

@@ -63,6 +63,7 @@ public:
 
     String absolute_path(const OpenFileDescription& description) const override;
 
+    u8 type_of_service() const { return m_type_of_service; }
     u8 ttl() const { return m_ttl; }
 
     enum class BufferMode {
@@ -123,6 +124,7 @@ private:
 
     u32 m_bytes_received { 0 };
 
+    u8 m_type_of_service { IPTOS_LOWDELAY };
     u8 m_ttl { 64 };
 
     bool m_can_read { false };

Kernel/Net/NetworkAdapter.cpp

@@ -47,7 +47,7 @@ void NetworkAdapter::send(const MACAddress& destination, const ARPPacket& packet
     send_packet({ (const u8*)eth, size_in_bytes });
 }
 
-void NetworkAdapter::fill_in_ipv4_header(PacketWithTimestamp& packet, IPv4Address const& source_ipv4, MACAddress const& destination_mac, IPv4Address const& destination_ipv4, IPv4Protocol protocol, size_t payload_size, u8 ttl)
+void NetworkAdapter::fill_in_ipv4_header(PacketWithTimestamp& packet, IPv4Address const& source_ipv4, MACAddress const& destination_mac, IPv4Address const& destination_ipv4, IPv4Protocol protocol, size_t payload_size, u8 type_of_service, u8 ttl)
 {
     size_t ipv4_packet_size = sizeof(IPv4Packet) + payload_size;
     VERIFY(ipv4_packet_size <= mtu());
@@ -62,6 +62,7 @@ void NetworkAdapter::fill_in_ipv4_header(PacketWithTimestamp& packet, IPv4Addres
     auto& ipv4 = *(IPv4Packet*)eth.payload();
     ipv4.set_version(4);
     ipv4.set_internet_header_length(5);
+    ipv4.set_dscp_and_ecn(type_of_service);
     ipv4.set_source(source_ipv4);
     ipv4.set_destination(destination_ipv4);
     ipv4.set_protocol((u8)protocol);

Kernel/Net/NetworkAdapter.h

@@ -69,7 +69,7 @@ public:
     void set_ipv4_gateway(const IPv4Address&);
 
     void send(const MACAddress&, const ARPPacket&);
-    void fill_in_ipv4_header(PacketWithTimestamp&, IPv4Address const&, MACAddress const&, IPv4Address const&, IPv4Protocol, size_t, u8);
+    void fill_in_ipv4_header(PacketWithTimestamp&, IPv4Address const&, MACAddress const&, IPv4Address const&, IPv4Protocol, size_t, u8 type_of_service, u8 ttl);
 
     size_t dequeue_packet(u8* buffer, size_t buffer_size, Time& packet_timestamp);
 

Kernel/Net/NetworkTask.cpp

@@ -258,7 +258,7 @@ void handle_icmp(EthernetFrameHeader const& eth, IPv4Packet const& ipv4_packet,
             dbgln("Could not allocate packet buffer while sending ICMP packet");
             return;
         }
-        adapter->fill_in_ipv4_header(*packet, adapter->ipv4_address(), eth.source(), ipv4_packet.source(), IPv4Protocol::ICMP, icmp_packet_size, 64);
+        adapter->fill_in_ipv4_header(*packet, adapter->ipv4_address(), eth.source(), ipv4_packet.source(), IPv4Protocol::ICMP, icmp_packet_size, 0, 64);
         memset(packet->buffer->data() + ipv4_payload_offset, 0, sizeof(ICMPEchoPacket));
         auto& response = *(ICMPEchoPacket*)(packet->buffer->data() + ipv4_payload_offset);
         response.header.set_type(ICMPType::EchoReply);
@@ -351,7 +351,7 @@ void send_tcp_rst(IPv4Packet const& ipv4_packet, TCPPacket const& tcp_packet, Re
         return;
     routing_decision.adapter->fill_in_ipv4_header(*packet, ipv4_packet.destination(),
         routing_decision.next_hop, ipv4_packet.source(), IPv4Protocol::TCP,
-        buffer_size - ipv4_payload_offset, 64);
+        buffer_size - ipv4_payload_offset, 0, 64);
 
     auto& rst_packet = *(TCPPacket*)(packet->buffer->data() + ipv4_payload_offset);
     rst_packet = {};

Kernel/Net/TCPSocket.cpp

@@ -207,7 +207,7 @@ KResult TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* payload,
         return set_so_error(ENOMEM);
     routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(),
         routing_decision.next_hop, peer_address(), IPv4Protocol::TCP,
-        buffer_size - ipv4_payload_offset, ttl());
+        buffer_size - ipv4_payload_offset, type_of_service(), ttl());
     memset(packet->buffer->data() + ipv4_payload_offset, 0, sizeof(TCPPacket));
     auto& tcp_packet = *(TCPPacket*)(packet->buffer->data() + ipv4_payload_offset);
     VERIFY(local_port());
@@ -587,7 +587,7 @@ void TCPSocket::retransmit_packets()
 
             routing_decision.adapter->fill_in_ipv4_header(*packet.buffer,
                 local_address(), routing_decision.next_hop, peer_address(),
-                IPv4Protocol::TCP, packet_buffer.size() - ipv4_payload_offset, ttl());
+                IPv4Protocol::TCP, packet_buffer.size() - ipv4_payload_offset, type_of_service(), ttl());
             routing_decision.adapter->send_packet(packet_buffer);
             m_packets_out++;
             m_bytes_out += packet_buffer.size();

Kernel/Net/UDPSocket.cpp

@@ -87,7 +87,7 @@ KResultOr<size_t> UDPSocket::protocol_send(const UserOrKernelBuffer& data, size_
     udp_packet.set_length(udp_buffer_size);
     SOCKET_TRY(data.read(udp_packet.payload(), data_length));
     routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(), routing_decision.next_hop,
-        peer_address(), IPv4Protocol::UDP, udp_buffer_size, ttl());
+        peer_address(), IPv4Protocol::UDP, udp_buffer_size, type_of_service(), ttl());
     routing_decision.adapter->send_packet(packet->bytes());
     return data_length;
 }