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https://github.com/SerenityOS/serenity
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12e534c8c6
This is an initial implementation, about as basic as intended by the RFC, and not configurable from userspace at the moment. It should reduce the amount of low-sized packets sent, reducing overhead and thereby network traffic.
684 lines
25 KiB
C++
684 lines
25 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Singleton.h>
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#include <AK/Time.h>
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#include <Kernel/Debug.h>
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#include <Kernel/Devices/Generic/RandomDevice.h>
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#include <Kernel/FileSystem/OpenFileDescription.h>
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#include <Kernel/Locking/MutexProtected.h>
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#include <Kernel/Net/EthernetFrameHeader.h>
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#include <Kernel/Net/IPv4.h>
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#include <Kernel/Net/NetworkAdapter.h>
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#include <Kernel/Net/NetworkingManagement.h>
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#include <Kernel/Net/Routing.h>
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#include <Kernel/Net/TCP.h>
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#include <Kernel/Net/TCPSocket.h>
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#include <Kernel/Security/Random.h>
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#include <Kernel/Tasks/Process.h>
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#include <Kernel/Time/TimeManagement.h>
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namespace Kernel {
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void TCPSocket::for_each(Function<void(TCPSocket const&)> callback)
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{
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sockets_by_tuple().for_each_shared([&](auto const& it) {
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callback(*it.value);
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});
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}
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ErrorOr<void> TCPSocket::try_for_each(Function<ErrorOr<void>(TCPSocket const&)> callback)
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{
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return sockets_by_tuple().with_shared([&](auto const& sockets) -> ErrorOr<void> {
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for (auto& it : sockets)
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TRY(callback(*it.value));
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return {};
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});
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}
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bool TCPSocket::unref() const
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{
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bool did_hit_zero = sockets_by_tuple().with_exclusive([&](auto& table) {
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if (deref_base())
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return false;
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table.remove(tuple());
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const_cast<TCPSocket&>(*this).revoke_weak_ptrs();
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return true;
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});
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if (did_hit_zero) {
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const_cast<TCPSocket&>(*this).will_be_destroyed();
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delete this;
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}
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return did_hit_zero;
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}
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void TCPSocket::set_state(State new_state)
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{
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dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket({}) state moving from {} to {}", this, to_string(m_state), to_string(new_state));
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auto was_disconnected = protocol_is_disconnected();
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auto previous_role = m_role;
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m_state = new_state;
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if (new_state == State::Established && m_direction == Direction::Outgoing) {
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set_role(Role::Connected);
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clear_so_error();
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}
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if (new_state == State::TimeWait) {
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// Once we hit TimeWait, we are only holding the socket in case there
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// are packets on the way which we wouldn't want a new socket to get hit
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// with, so there's no point in keeping the receive buffer around.
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drop_receive_buffer();
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}
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if (new_state == State::Closed) {
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closing_sockets().with_exclusive([&](auto& table) {
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table.remove(tuple());
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});
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if (m_originator)
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release_to_originator();
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}
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if (previous_role != m_role || was_disconnected != protocol_is_disconnected())
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evaluate_block_conditions();
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}
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static Singleton<MutexProtected<HashMap<IPv4SocketTuple, RefPtr<TCPSocket>>>> s_socket_closing;
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MutexProtected<HashMap<IPv4SocketTuple, RefPtr<TCPSocket>>>& TCPSocket::closing_sockets()
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{
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return *s_socket_closing;
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}
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static Singleton<MutexProtected<HashMap<IPv4SocketTuple, TCPSocket*>>> s_socket_tuples;
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MutexProtected<HashMap<IPv4SocketTuple, TCPSocket*>>& TCPSocket::sockets_by_tuple()
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{
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return *s_socket_tuples;
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}
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RefPtr<TCPSocket> TCPSocket::from_tuple(IPv4SocketTuple const& tuple)
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{
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return sockets_by_tuple().with_shared([&](auto const& table) -> RefPtr<TCPSocket> {
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auto exact_match = table.get(tuple);
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if (exact_match.has_value())
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return { *exact_match.value() };
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auto address_tuple = IPv4SocketTuple(tuple.local_address(), tuple.local_port(), IPv4Address(), 0);
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auto address_match = table.get(address_tuple);
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if (address_match.has_value())
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return { *address_match.value() };
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auto wildcard_tuple = IPv4SocketTuple(IPv4Address(), tuple.local_port(), IPv4Address(), 0);
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auto wildcard_match = table.get(wildcard_tuple);
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if (wildcard_match.has_value())
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return { *wildcard_match.value() };
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return {};
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});
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}
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ErrorOr<NonnullRefPtr<TCPSocket>> TCPSocket::try_create_client(IPv4Address const& new_local_address, u16 new_local_port, IPv4Address const& new_peer_address, u16 new_peer_port)
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{
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auto tuple = IPv4SocketTuple(new_local_address, new_local_port, new_peer_address, new_peer_port);
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return sockets_by_tuple().with_exclusive([&](auto& table) -> ErrorOr<NonnullRefPtr<TCPSocket>> {
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if (table.contains(tuple))
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return EEXIST;
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auto receive_buffer = TRY(try_create_receive_buffer());
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auto client = TRY(TCPSocket::try_create(protocol(), move(receive_buffer)));
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client->set_setup_state(SetupState::InProgress);
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client->set_local_address(new_local_address);
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client->set_local_port(new_local_port);
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client->set_peer_address(new_peer_address);
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client->set_peer_port(new_peer_port);
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client->set_bound(true);
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client->set_direction(Direction::Incoming);
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client->set_originator(*this);
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m_pending_release_for_accept.set(tuple, client);
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table.set(tuple, client);
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return { move(client) };
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});
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}
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void TCPSocket::release_to_originator()
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{
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VERIFY(!!m_originator);
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m_originator.strong_ref()->release_for_accept(*this);
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m_originator.clear();
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}
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void TCPSocket::release_for_accept(NonnullRefPtr<TCPSocket> socket)
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{
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VERIFY(m_pending_release_for_accept.contains(socket->tuple()));
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m_pending_release_for_accept.remove(socket->tuple());
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// FIXME: Should we observe this error somehow?
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[[maybe_unused]] auto rc = queue_connection_from(move(socket));
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}
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TCPSocket::TCPSocket(int protocol, NonnullOwnPtr<DoubleBuffer> receive_buffer, NonnullOwnPtr<KBuffer> scratch_buffer)
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: IPv4Socket(SOCK_STREAM, protocol, move(receive_buffer), move(scratch_buffer))
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, m_last_ack_sent_time(TimeManagement::the().monotonic_time())
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, m_last_retransmit_time(TimeManagement::the().monotonic_time())
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{
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}
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TCPSocket::~TCPSocket()
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{
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dequeue_for_retransmit();
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dbgln_if(TCP_SOCKET_DEBUG, "~TCPSocket in state {}", to_string(state()));
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}
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ErrorOr<NonnullRefPtr<TCPSocket>> TCPSocket::try_create(int protocol, NonnullOwnPtr<DoubleBuffer> receive_buffer)
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{
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// Note: Scratch buffer is only used for SOCK_STREAM sockets.
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auto scratch_buffer = TRY(KBuffer::try_create_with_size("TCPSocket: Scratch buffer"sv, 65536));
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return adopt_nonnull_ref_or_enomem(new (nothrow) TCPSocket(protocol, move(receive_buffer), move(scratch_buffer)));
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}
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ErrorOr<size_t> TCPSocket::protocol_size(ReadonlyBytes raw_ipv4_packet)
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{
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auto& ipv4_packet = *reinterpret_cast<IPv4Packet const*>(raw_ipv4_packet.data());
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auto& tcp_packet = *static_cast<TCPPacket const*>(ipv4_packet.payload());
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return raw_ipv4_packet.size() - sizeof(IPv4Packet) - tcp_packet.header_size();
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}
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ErrorOr<size_t> TCPSocket::protocol_receive(ReadonlyBytes raw_ipv4_packet, UserOrKernelBuffer& buffer, size_t buffer_size, [[maybe_unused]] int flags)
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{
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auto& ipv4_packet = *reinterpret_cast<IPv4Packet const*>(raw_ipv4_packet.data());
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auto& tcp_packet = *static_cast<TCPPacket const*>(ipv4_packet.payload());
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size_t payload_size = raw_ipv4_packet.size() - sizeof(IPv4Packet) - tcp_packet.header_size();
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dbgln_if(TCP_SOCKET_DEBUG, "payload_size {}, will it fit in {}?", payload_size, buffer_size);
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VERIFY(buffer_size >= payload_size);
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SOCKET_TRY(buffer.write(tcp_packet.payload(), payload_size));
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return payload_size;
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}
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ErrorOr<size_t> TCPSocket::protocol_send(UserOrKernelBuffer const& data, size_t data_length)
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{
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auto adapter = bound_interface().with([](auto& bound_device) -> RefPtr<NetworkAdapter> { return bound_device; });
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RoutingDecision routing_decision = route_to(peer_address(), local_address(), adapter);
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if (routing_decision.is_zero())
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return set_so_error(EHOSTUNREACH);
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size_t mss = routing_decision.adapter->mtu() - sizeof(IPv4Packet) - sizeof(TCPPacket);
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// RFC 896 (Nagle’s algorithm): https://www.ietf.org/rfc/rfc0896
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// "The solution is to inhibit the sending of new TCP segments when
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// new outgoing data arrives from the user if any previously
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// transmitted data on the connection remains unacknowledged. This
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// inhibition is to be unconditional; no timers, tests for size of
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// data received, or other conditions are required."
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// FIXME: Make this configurable via TCP_NODELAY.
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auto has_unacked_data = m_unacked_packets.with_shared([&](auto const& packets) { return packets.size > 0; });
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if (has_unacked_data && data_length < mss)
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return 0;
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data_length = min(data_length, mss);
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TRY(send_tcp_packet(TCPFlags::PSH | TCPFlags::ACK, &data, data_length, &routing_decision));
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return data_length;
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}
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ErrorOr<void> TCPSocket::send_ack(bool allow_duplicate)
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{
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if (!allow_duplicate && m_last_ack_number_sent == m_ack_number)
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return {};
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return send_tcp_packet(TCPFlags::ACK);
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}
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ErrorOr<void> TCPSocket::send_tcp_packet(u16 flags, UserOrKernelBuffer const* payload, size_t payload_size, RoutingDecision* user_routing_decision)
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{
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auto adapter = bound_interface().with([](auto& bound_device) -> RefPtr<NetworkAdapter> { return bound_device; });
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RoutingDecision routing_decision = user_routing_decision ? *user_routing_decision : route_to(peer_address(), local_address(), adapter);
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if (routing_decision.is_zero())
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return set_so_error(EHOSTUNREACH);
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auto ipv4_payload_offset = routing_decision.adapter->ipv4_payload_offset();
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bool const has_mss_option = flags == TCPFlags::SYN;
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const size_t options_size = has_mss_option ? sizeof(TCPOptionMSS) : 0;
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const size_t tcp_header_size = sizeof(TCPPacket) + options_size;
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const size_t buffer_size = ipv4_payload_offset + tcp_header_size + payload_size;
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auto packet = routing_decision.adapter->acquire_packet_buffer(buffer_size);
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if (!packet)
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return set_so_error(ENOMEM);
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routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(),
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routing_decision.next_hop, peer_address(), IPv4Protocol::TCP,
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buffer_size - ipv4_payload_offset, type_of_service(), ttl());
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memset(packet->buffer->data() + ipv4_payload_offset, 0, sizeof(TCPPacket));
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auto& tcp_packet = *(TCPPacket*)(packet->buffer->data() + ipv4_payload_offset);
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VERIFY(local_port());
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tcp_packet.set_source_port(local_port());
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tcp_packet.set_destination_port(peer_port());
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tcp_packet.set_window_size(NumericLimits<u16>::max());
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tcp_packet.set_sequence_number(m_sequence_number);
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tcp_packet.set_data_offset(tcp_header_size / sizeof(u32));
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tcp_packet.set_flags(flags);
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if (payload) {
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if (auto result = payload->read(tcp_packet.payload(), payload_size); result.is_error()) {
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routing_decision.adapter->release_packet_buffer(*packet);
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return set_so_error(result.release_error());
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}
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}
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if (flags & TCPFlags::ACK) {
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m_last_ack_number_sent = m_ack_number;
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m_last_ack_sent_time = TimeManagement::the().monotonic_time();
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tcp_packet.set_ack_number(m_ack_number);
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}
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if (flags & TCPFlags::SYN) {
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++m_sequence_number;
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} else {
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m_sequence_number += payload_size;
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}
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if (has_mss_option) {
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u16 mss = routing_decision.adapter->mtu() - sizeof(IPv4Packet) - sizeof(TCPPacket);
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TCPOptionMSS mss_option { mss };
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VERIFY(packet->buffer->size() >= ipv4_payload_offset + sizeof(TCPPacket) + sizeof(mss_option));
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memcpy(packet->buffer->data() + ipv4_payload_offset + sizeof(TCPPacket), &mss_option, sizeof(mss_option));
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}
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tcp_packet.set_checksum(compute_tcp_checksum(local_address(), peer_address(), tcp_packet, payload_size));
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bool expect_ack { tcp_packet.has_syn() || payload_size > 0 };
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if (expect_ack) {
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bool append_failed { false };
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m_unacked_packets.with_exclusive([&](auto& unacked_packets) {
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auto result = unacked_packets.packets.try_append({ m_sequence_number, packet, ipv4_payload_offset, *routing_decision.adapter });
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if (result.is_error()) {
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dbgln("TCPSocket: Dropped outbound packet because try_append() failed");
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append_failed = true;
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return;
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}
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unacked_packets.size += payload_size;
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enqueue_for_retransmit();
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});
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if (append_failed)
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return set_so_error(ENOMEM);
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}
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m_packets_out++;
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m_bytes_out += buffer_size;
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routing_decision.adapter->send_packet(packet->bytes());
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if (!expect_ack)
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routing_decision.adapter->release_packet_buffer(*packet);
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return {};
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}
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void TCPSocket::receive_tcp_packet(TCPPacket const& packet, u16 size)
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{
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if (packet.has_ack()) {
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u32 ack_number = packet.ack_number();
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dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket: receive_tcp_packet: {}", ack_number);
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int removed = 0;
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m_unacked_packets.with_exclusive([&](auto& unacked_packets) {
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while (!unacked_packets.packets.is_empty()) {
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auto& packet = unacked_packets.packets.first();
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dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket: iterate: {}", packet.ack_number);
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if (packet.ack_number <= ack_number) {
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auto old_adapter = packet.adapter.strong_ref();
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if (old_adapter)
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old_adapter->release_packet_buffer(*packet.buffer);
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TCPPacket& tcp_packet = *(TCPPacket*)(packet.buffer->buffer->data() + packet.ipv4_payload_offset);
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if (m_send_window_size != tcp_packet.window_size()) {
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m_send_window_size = tcp_packet.window_size();
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}
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auto payload_size = packet.buffer->buffer->data() + packet.buffer->buffer->size() - (u8*)tcp_packet.payload();
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unacked_packets.size -= payload_size;
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evaluate_block_conditions();
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unacked_packets.packets.take_first();
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removed++;
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} else {
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break;
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}
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}
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if (unacked_packets.packets.is_empty()) {
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m_retransmit_attempts = 0;
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dequeue_for_retransmit();
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}
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dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket: receive_tcp_packet acknowledged {} packets", removed);
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});
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}
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m_packets_in++;
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m_bytes_in += packet.header_size() + size;
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}
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bool TCPSocket::should_delay_next_ack() const
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{
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// FIXME: We don't know the MSS here so make a reasonable guess.
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const size_t mss = 1500;
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// RFC 1122 says we should send an ACK for every two full-sized segments.
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if (m_ack_number >= m_last_ack_number_sent + 2 * mss)
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return false;
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// RFC 1122 says we should not delay ACKs for more than 500 milliseconds.
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if (TimeManagement::the().monotonic_time(TimePrecision::Precise) >= m_last_ack_sent_time + Duration::from_milliseconds(500))
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return false;
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return true;
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}
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NetworkOrdered<u16> TCPSocket::compute_tcp_checksum(IPv4Address const& source, IPv4Address const& destination, TCPPacket const& packet, u16 payload_size)
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{
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union PseudoHeader {
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struct [[gnu::packed]] {
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IPv4Address source;
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IPv4Address destination;
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u8 zero;
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u8 protocol;
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NetworkOrdered<u16> payload_size;
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} header;
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u16 raw[6];
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};
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static_assert(sizeof(PseudoHeader) == 12);
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Checked<u16> packet_size = packet.header_size();
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packet_size += payload_size;
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VERIFY(!packet_size.has_overflow());
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PseudoHeader pseudo_header { .header = { source, destination, 0, (u8)IPv4Protocol::TCP, packet_size.value() } };
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u32 checksum = 0;
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auto* raw_pseudo_header = pseudo_header.raw;
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for (size_t i = 0; i < sizeof(pseudo_header) / sizeof(u16); ++i) {
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checksum += AK::convert_between_host_and_network_endian(raw_pseudo_header[i]);
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if (checksum > 0xffff)
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checksum = (checksum >> 16) + (checksum & 0xffff);
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}
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auto* raw_packet = bit_cast<u16*>(&packet);
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for (size_t i = 0; i < packet.header_size() / sizeof(u16); ++i) {
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checksum += AK::convert_between_host_and_network_endian(raw_packet[i]);
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if (checksum > 0xffff)
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checksum = (checksum >> 16) + (checksum & 0xffff);
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}
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VERIFY(packet.data_offset() * 4 == packet.header_size());
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auto* raw_payload = bit_cast<u16*>(packet.payload());
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for (size_t i = 0; i < payload_size / sizeof(u16); ++i) {
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checksum += AK::convert_between_host_and_network_endian(raw_payload[i]);
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if (checksum > 0xffff)
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checksum = (checksum >> 16) + (checksum & 0xffff);
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}
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if (payload_size & 1) {
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u16 expanded_byte = ((u8 const*)packet.payload())[payload_size - 1] << 8;
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checksum += expanded_byte;
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if (checksum > 0xffff)
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checksum = (checksum >> 16) + (checksum & 0xffff);
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}
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return ~(checksum & 0xffff);
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}
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ErrorOr<void> TCPSocket::protocol_bind()
|
||
{
|
||
dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket::protocol_bind(), local_port() is {}", local_port());
|
||
// Check that we do have the address we're trying to bind to.
|
||
TRY(m_adapter.with([this](auto& adapter) -> ErrorOr<void> {
|
||
if (has_specific_local_address() && !adapter) {
|
||
adapter = NetworkingManagement::the().from_ipv4_address(local_address());
|
||
if (!adapter)
|
||
return set_so_error(EADDRNOTAVAIL);
|
||
}
|
||
return {};
|
||
}));
|
||
|
||
if (local_port() == 0) {
|
||
// Allocate an unused ephemeral port.
|
||
constexpr u16 first_ephemeral_port = 32768;
|
||
constexpr u16 last_ephemeral_port = 60999;
|
||
constexpr u16 ephemeral_port_range_size = last_ephemeral_port - first_ephemeral_port;
|
||
u16 first_scan_port = first_ephemeral_port + get_good_random<u16>() % ephemeral_port_range_size;
|
||
|
||
return sockets_by_tuple().with_exclusive([&](auto& table) -> ErrorOr<void> {
|
||
u16 port = first_scan_port;
|
||
while (true) {
|
||
IPv4SocketTuple proposed_tuple(local_address(), port, peer_address(), peer_port());
|
||
|
||
auto it = table.find(proposed_tuple);
|
||
if (it == table.end()) {
|
||
set_local_port(port);
|
||
table.set(proposed_tuple, this);
|
||
dbgln_if(TCP_SOCKET_DEBUG, "...allocated port {}, tuple {}", port, proposed_tuple.to_string());
|
||
return {};
|
||
}
|
||
++port;
|
||
if (port > last_ephemeral_port)
|
||
port = first_ephemeral_port;
|
||
if (port == first_scan_port)
|
||
break;
|
||
}
|
||
return set_so_error(EADDRINUSE);
|
||
});
|
||
} else {
|
||
// Verify that the user-supplied port is not already used by someone else.
|
||
bool ok = sockets_by_tuple().with_exclusive([&](auto& table) -> bool {
|
||
if (table.contains(tuple()))
|
||
return false;
|
||
table.set(tuple(), this);
|
||
return true;
|
||
});
|
||
if (!ok)
|
||
return set_so_error(EADDRINUSE);
|
||
return {};
|
||
}
|
||
}
|
||
|
||
ErrorOr<void> TCPSocket::protocol_listen()
|
||
{
|
||
set_direction(Direction::Passive);
|
||
set_state(State::Listen);
|
||
set_setup_state(SetupState::Completed);
|
||
return {};
|
||
}
|
||
|
||
ErrorOr<void> TCPSocket::protocol_connect(OpenFileDescription& description)
|
||
{
|
||
MutexLocker locker(mutex());
|
||
|
||
auto routing_decision = route_to(peer_address(), local_address());
|
||
if (routing_decision.is_zero())
|
||
return set_so_error(EHOSTUNREACH);
|
||
if (!has_specific_local_address())
|
||
set_local_address(routing_decision.adapter->ipv4_address());
|
||
|
||
TRY(ensure_bound());
|
||
|
||
m_sequence_number = get_good_random<u32>();
|
||
m_ack_number = 0;
|
||
|
||
set_setup_state(SetupState::InProgress);
|
||
TRY(send_tcp_packet(TCPFlags::SYN));
|
||
m_state = State::SynSent;
|
||
set_role(Role::Connecting);
|
||
m_direction = Direction::Outgoing;
|
||
|
||
evaluate_block_conditions();
|
||
|
||
if (description.is_blocking()) {
|
||
locker.unlock();
|
||
auto unblock_flags = Thread::FileBlocker::BlockFlags::None;
|
||
if (Thread::current()->block<Thread::ConnectBlocker>({}, description, unblock_flags).was_interrupted())
|
||
return set_so_error(EINTR);
|
||
locker.lock();
|
||
VERIFY(setup_state() == SetupState::Completed);
|
||
if (has_error()) { // TODO: check unblock_flags
|
||
set_role(Role::None);
|
||
if (error() == TCPSocket::Error::RetransmitTimeout)
|
||
return set_so_error(ETIMEDOUT);
|
||
else
|
||
return set_so_error(ECONNREFUSED);
|
||
}
|
||
return {};
|
||
}
|
||
|
||
return set_so_error(EINPROGRESS);
|
||
}
|
||
|
||
bool TCPSocket::protocol_is_disconnected() const
|
||
{
|
||
switch (m_state) {
|
||
case State::Closed:
|
||
case State::CloseWait:
|
||
case State::LastAck:
|
||
case State::FinWait1:
|
||
case State::FinWait2:
|
||
case State::Closing:
|
||
case State::TimeWait:
|
||
return true;
|
||
default:
|
||
return false;
|
||
}
|
||
}
|
||
|
||
void TCPSocket::shut_down_for_writing()
|
||
{
|
||
if (state() == State::Established) {
|
||
dbgln_if(TCP_SOCKET_DEBUG, " Sending FIN from Established and moving into FinWait1");
|
||
(void)send_tcp_packet(TCPFlags::FIN | TCPFlags::ACK);
|
||
set_state(State::FinWait1);
|
||
} else {
|
||
dbgln(" Shutting down TCPSocket for writing but not moving to FinWait1 since state is {}", to_string(state()));
|
||
}
|
||
}
|
||
|
||
ErrorOr<void> TCPSocket::close()
|
||
{
|
||
MutexLocker locker(mutex());
|
||
auto result = IPv4Socket::close();
|
||
if (state() == State::CloseWait) {
|
||
dbgln_if(TCP_SOCKET_DEBUG, " Sending FIN from CloseWait and moving into LastAck");
|
||
[[maybe_unused]] auto rc = send_tcp_packet(TCPFlags::FIN | TCPFlags::ACK);
|
||
set_state(State::LastAck);
|
||
}
|
||
|
||
if (state() != State::Closed && state() != State::Listen)
|
||
closing_sockets().with_exclusive([&](auto& table) {
|
||
table.set(tuple(), *this);
|
||
});
|
||
return result;
|
||
}
|
||
|
||
static Singleton<MutexProtected<TCPSocket::RetransmitList>> s_sockets_for_retransmit;
|
||
|
||
MutexProtected<TCPSocket::RetransmitList>& TCPSocket::sockets_for_retransmit()
|
||
{
|
||
return *s_sockets_for_retransmit;
|
||
}
|
||
|
||
void TCPSocket::enqueue_for_retransmit()
|
||
{
|
||
sockets_for_retransmit().with_exclusive([&](auto& list) {
|
||
list.append(*this);
|
||
});
|
||
}
|
||
|
||
void TCPSocket::dequeue_for_retransmit()
|
||
{
|
||
sockets_for_retransmit().with_exclusive([&](auto& list) {
|
||
list.remove(*this);
|
||
});
|
||
}
|
||
|
||
void TCPSocket::retransmit_packets()
|
||
{
|
||
auto now = TimeManagement::the().monotonic_time();
|
||
|
||
// RFC6298 says we should have at least one second between retransmits. According to
|
||
// RFC1122 we must do exponential backoff - even for SYN packets.
|
||
i64 retransmit_interval = 1;
|
||
for (decltype(m_retransmit_attempts) i = 0; i < m_retransmit_attempts; i++)
|
||
retransmit_interval *= 2;
|
||
|
||
if (m_last_retransmit_time > now - Duration::from_seconds(retransmit_interval))
|
||
return;
|
||
|
||
dbgln_if(TCP_SOCKET_DEBUG, "TCPSocket({}) handling retransmit", this);
|
||
|
||
m_last_retransmit_time = now;
|
||
++m_retransmit_attempts;
|
||
|
||
if (m_retransmit_attempts > maximum_retransmits) {
|
||
set_state(TCPSocket::State::Closed);
|
||
set_error(TCPSocket::Error::RetransmitTimeout);
|
||
set_setup_state(Socket::SetupState::Completed);
|
||
return;
|
||
}
|
||
|
||
auto adapter = bound_interface().with([](auto& bound_device) -> RefPtr<NetworkAdapter> { return bound_device; });
|
||
auto routing_decision = route_to(peer_address(), local_address(), adapter);
|
||
if (routing_decision.is_zero())
|
||
return;
|
||
|
||
m_unacked_packets.with_exclusive([&](auto& unacked_packets) {
|
||
for (auto& packet : unacked_packets.packets) {
|
||
packet.tx_counter++;
|
||
|
||
if constexpr (TCP_SOCKET_DEBUG) {
|
||
auto& tcp_packet = *(const TCPPacket*)(packet.buffer->buffer->data() + packet.ipv4_payload_offset);
|
||
dbgln("Sending TCP packet from {}:{} to {}:{} with ({}{}{}{}) seq_no={}, ack_no={}, tx_counter={}",
|
||
local_address(), local_port(),
|
||
peer_address(), peer_port(),
|
||
(tcp_packet.has_syn() ? "SYN " : ""),
|
||
(tcp_packet.has_ack() ? "ACK " : ""),
|
||
(tcp_packet.has_fin() ? "FIN " : ""),
|
||
(tcp_packet.has_rst() ? "RST " : ""),
|
||
tcp_packet.sequence_number(),
|
||
tcp_packet.ack_number(),
|
||
packet.tx_counter);
|
||
}
|
||
|
||
size_t ipv4_payload_offset = routing_decision.adapter->ipv4_payload_offset();
|
||
if (ipv4_payload_offset != packet.ipv4_payload_offset) {
|
||
// FIXME: Add support for this. This can happen if after a route change
|
||
// we ended up on another adapter which doesn't have the same layer 2 type
|
||
// like the previous adapter.
|
||
VERIFY_NOT_REACHED();
|
||
}
|
||
|
||
auto packet_buffer = packet.buffer->bytes();
|
||
|
||
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, type_of_service(), ttl());
|
||
routing_decision.adapter->send_packet(packet_buffer);
|
||
m_packets_out++;
|
||
m_bytes_out += packet_buffer.size();
|
||
}
|
||
});
|
||
}
|
||
|
||
bool TCPSocket::can_write(OpenFileDescription const& file_description, u64 size) const
|
||
{
|
||
if (!IPv4Socket::can_write(file_description, size))
|
||
return false;
|
||
|
||
if (m_state == State::SynSent || m_state == State::SynReceived)
|
||
return false;
|
||
|
||
if (!file_description.is_blocking())
|
||
return true;
|
||
|
||
return m_unacked_packets.with_shared([&](auto& unacked_packets) {
|
||
return unacked_packets.size + size <= m_send_window_size;
|
||
});
|
||
}
|
||
}
|