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Kernel/Net: Avoid a heap allocation for every outgoing UDP packet

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We can use a stack buffer to build the UDP packet instead.
This commit is contained in:
Andreas Kling 2020-12-18 17:57:58 +01:00
parent 8cc81c2953
commit befabe31c9
1 changed files with 9 additions and 6 deletions
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15
Kernel/Net/UDPSocket.cpp
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@ -96,16 +96,19 @@ KResultOr<size_t> 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<UDPPacket*>(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;
}