From befabe31c9affc8a6822a4d84b74b5fb9a5be77f Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Fri, 18 Dec 2020 17:57:58 +0100 Subject: [PATCH] Kernel/Net: Avoid a heap allocation for every outgoing UDP packet We can use a stack buffer to build the UDP packet instead. --- Kernel/Net/UDPSocket.cpp | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/Kernel/Net/UDPSocket.cpp b/Kernel/Net/UDPSocket.cpp index 8698201518..0ee41ab36d 100644 --- a/Kernel/Net/UDPSocket.cpp +++ b/Kernel/Net/UDPSocket.cpp @@ -96,16 +96,19 @@ KResultOr UDPSocket::protocol_send(const UserOrKernelBuffer& data, size_ auto routing_decision = route_to(peer_address(), local_address(), bound_interface()); if (routing_decision.is_zero()) return KResult(-EHOSTUNREACH); - auto buffer = ByteBuffer::create_zeroed(sizeof(UDPPacket) + data_length); - auto& udp_packet = *(UDPPacket*)(buffer.data()); + const size_t buffer_size = sizeof(UDPPacket) + data_length; + + alignas(UDPPacket) u8 buffer[buffer_size]; + new (buffer) UDPPacket; + + auto& udp_packet = *reinterpret_cast(buffer); udp_packet.set_source_port(local_port()); udp_packet.set_destination_port(peer_port()); - udp_packet.set_length(sizeof(UDPPacket) + data_length); + udp_packet.set_length(buffer_size); if (!data.read(udp_packet.payload(), data_length)) return KResult(-EFAULT); - klog() << "sending as udp packet from " << routing_decision.adapter->ipv4_address().to_string().characters() << ":" << local_port() << " to " << peer_address().to_string().characters() << ":" << peer_port() << "!"; - auto udp_packet_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&udp_packet); - routing_decision.adapter->send_ipv4(routing_decision.next_hop, peer_address(), IPv4Protocol::UDP, udp_packet_buffer, buffer.size(), ttl()); + + routing_decision.adapter->send_ipv4(routing_decision.next_hop, peer_address(), IPv4Protocol::UDP, UserOrKernelBuffer::for_kernel_buffer(buffer), buffer_size, ttl()); return data_length; }