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Kernel: Cleanup TCP code

This commit is contained in:
Bananymous 2024-02-12 15:32:01 +02:00
parent ccde8148a7
commit f50b4be162
2 changed files with 97 additions and 93 deletions
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40
kernel/include/kernel/Networking/TCPSocket.h
View File

@ -73,17 +73,33 @@ namespace Kernel
TimeWait,
};
struct WindowInfo
struct RecvWindowInfo
{
uint32_t mss { 0 };
uint16_t size { 0 };
uint8_t scale { 0 };
uint32_t start_seq { 0 };
uint32_t current_seq { 0 };
BAN::Atomic<uint32_t> ack_number { 0 };
uint32_t data_size { 0 };
uint64_t send_time_ms { 0 };
BAN::UniqPtr<VirtualRange> window;
uint32_t start_seq { 0 }; // sequence number of first byte in buffer
bool has_ghost_byte { false };
uint32_t data_size { 0 }; // number of bytes in this buffer
BAN::UniqPtr<VirtualRange> buffer;
};
struct SendWindowInfo
{
uint32_t mss { 0 }; // maximum segment size
uint16_t non_scaled_size { 0 }; // window size without scaling
uint8_t scale { 0 }; // window scale
uint32_t scaled_size() const { return (uint32_t)non_scaled_size << scale; }
uint32_t start_seq { 0 }; // sequence number of first byte in buffer
uint32_t current_seq { 0 }; // sequence number of next send
uint32_t current_ack { 0 }; // sequence number aknowledged by connection
uint64_t last_send_ms { 0 }; // last send time, used for retransmission timeout
bool has_ghost_byte { false };
uint32_t data_size { 0 }; // number of bytes in this buffer
BAN::UniqPtr<VirtualRange> buffer;
};
private:
@ -104,8 +120,8 @@ namespace Kernel
BAN::Atomic<bool> m_should_ack { false };
WindowInfo m_recv_window;
WindowInfo m_send_window;
RecvWindowInfo m_recv_window;
SendWindowInfo m_send_window;
struct ConnectionInfo
{

150
kernel/kernel/Networking/TCPSocket.cpp
View File

@ -27,7 +27,7 @@ namespace Kernel
if (socket_ptr == nullptr)
return BAN::Error::from_errno(ENOMEM);
auto socket = BAN::RefPtr<TCPSocket>::adopt(socket_ptr);
socket->m_recv_window.window = TRY(VirtualRange::create_to_vaddr_range(
socket->m_recv_window.buffer = TRY(VirtualRange::create_to_vaddr_range(
PageTable::kernel(),
KERNEL_OFFSET,
~(vaddr_t)0,
@ -35,7 +35,7 @@ namespace Kernel
PageTable::Flags::ReadWrite | PageTable::Flags::Present,
true
));
socket->m_send_window.window = TRY(VirtualRange::create_to_vaddr_range(
socket->m_send_window.buffer = TRY(VirtualRange::create_to_vaddr_range(
PageTable::kernel(),
KERNEL_OFFSET,
~(vaddr_t)0,
@ -43,8 +43,6 @@ namespace Kernel
PageTable::Flags::ReadWrite | PageTable::Flags::Present,
true
));
socket->m_recv_window.size = socket->m_recv_window.window->size();
socket->m_recv_window.scale = 0;
socket->m_process = Process::create_kernel(
[](void* socket_ptr)
{
@ -58,7 +56,6 @@ namespace Kernel
: NetworkSocket(network_layer, ino, inode_info)
{
m_send_window.start_seq = Random::get_u32() & 0x7FFFFFFF;
m_send_window.ack_number = m_send_window.start_seq;
m_send_window.current_seq = m_send_window.start_seq;
}
@ -95,13 +92,8 @@ namespace Kernel
case State::Listen: ASSERT_NOT_REACHED();
}
ASSERT(m_connection_info.has_value());
auto* target_address = reinterpret_cast<const sockaddr*>(&m_connection_info->address);
auto target_address_len = m_connection_info->address_len;
m_state = State::FinWait1;
if (auto ret = m_network_layer.sendto(*this, {}, target_address, target_address_len); ret.is_error())
dwarnln("{}", ret.error());
m_should_ack = true;
dprintln_if(DEBUG_TCP, "Initiated close");
}
@ -140,8 +132,6 @@ namespace Kernel
m_connection_info.emplace(sockaddr_storage {}, address_len);
memcpy(&m_connection_info->address, address, address_len);
m_recv_window.mss = m_interface->payload_mtu() - m_network_layer.header_size();
TRY(m_network_layer.sendto(*this, {}, address, address_len));
ASSERT(m_state == State::SynSent);
dprintln_if(DEBUG_TCP, "Sent SYN");
@ -211,10 +201,12 @@ namespace Kernel
header.dst_port = dst_port;
header.src_port = m_port;
header.seq_number = m_send_window.current_seq;
header.ack_number = m_recv_window.ack_number.load();
header.seq_number = m_send_window.current_seq + m_send_window.has_ghost_byte;
header.ack_number = m_recv_window.start_seq + m_recv_window.data_size + m_recv_window.has_ghost_byte;
header.data_offset = (sizeof(TCPHeader) + m_tcp_options_bytes) / sizeof(uint32_t);
header.window_size = m_recv_window.window->size();
header.window_size = m_recv_window.buffer->size();
ASSERT(m_recv_window.buffer->size() < 1 << (8 * sizeof(header.window_size)));
switch (m_state)
{
@ -222,9 +214,11 @@ namespace Kernel
{
LockGuard _(m_lock);
header.syn = 1;
add_tcp_header_option<0, TCPOption::MaximumSeqmentSize>(header, m_recv_window.mss);
add_tcp_header_option<4, TCPOption::WindowScale>(header, m_recv_window.scale);
add_tcp_header_option<0, TCPOption::MaximumSeqmentSize>(header, m_interface->payload_mtu() - m_network_layer.header_size());
add_tcp_header_option<4, TCPOption::WindowScale>(header, 0);
m_state = State::SynSent;
m_send_window.start_seq++;
m_send_window.current_seq = m_send_window.start_seq;
break;
}
case State::SynSent:
@ -242,9 +236,8 @@ namespace Kernel
LockGuard _(m_lock);
header.ack = 1;
header.fin = 1;
header.ack_number = header.ack_number + 1;
m_state = State::LastAck;
dprintln_if(DEBUG_TCP, "Waiting for last ack");
dprintln_if(DEBUG_TCP, "Waiting for last ACK");
break;
}
case State::FinWait1:
@ -259,10 +252,9 @@ namespace Kernel
{
LockGuard _(m_lock);
header.ack = 1;
header.seq_number = header.seq_number + 1;
header.ack_number = header.ack_number + 1;
m_state = State::TimeWait;
m_time_wait_start_ms = SystemTimer::get().ms_since_boot();
dprintln_if(DEBUG_TCP, "Sent final ACK");
break;
}
case State::Listen: ASSERT_NOT_REACHED();
@ -307,7 +299,7 @@ namespace Kernel
auto& header = buffer.as<const TCPHeader>();
m_send_window.size = header.window_size;
m_send_window.non_scaled_size = header.window_size;
auto payload = buffer.slice(header.data_offset * sizeof(uint32_t));
@ -322,20 +314,22 @@ namespace Kernel
LockGuard _(m_lock);
if (header.ack_number != m_send_window.current_seq)
{
dprintln_if(DEBUG_TCP, "Invalid ack number in SYN/ACK", (uint32_t)header.ack_number, m_send_window.current_seq);
break;
}
auto options = parse_tcp_options(header);
if (options.maximum_seqment_size.has_value())
m_send_window.mss = *options.maximum_seqment_size;
if (options.window_scale.has_value())
m_send_window.scale = *options.window_scale;
else
m_recv_window.scale = 0;
m_send_window.start_seq = m_send_window.start_seq + 1;
m_send_window.ack_number = m_send_window.start_seq;
m_send_window.current_seq = m_send_window.start_seq;
m_send_window.start_seq = m_send_window.current_seq;
m_send_window.current_ack = m_send_window.current_seq;
m_recv_window.start_seq = header.seq_number + 1;
m_recv_window.ack_number = m_recv_window.start_seq;
dprintln_if(DEBUG_TCP, "Got SYN/ACK");
@ -344,11 +338,6 @@ namespace Kernel
break;
}
case State::FinWait2:
if (!header.ack)
break;
if (header.fin)
m_should_ack = true;
// fall through
case State::TimeWait:
case State::CloseWait:
case State::Established:
@ -357,20 +346,28 @@ namespace Kernel
break;
LockGuard _(m_lock);
if (header.fin)
{
if (m_recv_window.start_seq + m_recv_window.data_size != header.seq_number)
dprintln_if(DEBUG_TCP, "Got FIN, but missing packets");
else
{
if (m_state == State::FinWait2)
m_send_window.has_ghost_byte = true;
else
m_state = State::CloseWait;
m_recv_window.has_ghost_byte = true;
m_should_ack = true;
m_state = State::CloseWait;
dprintln_if(DEBUG_TCP, "Got FIN");
}
break;
}
if (header.ack_number > m_send_window.ack_number)
m_send_window.ack_number = header.ack_number;
if (header.ack_number > m_send_window.current_ack)
m_send_window.current_ack = header.ack_number;
if (payload.size() > 0)
{
if (header.seq_number != m_recv_window.start_seq + m_recv_window.data_size)
@ -379,13 +376,13 @@ namespace Kernel
break;
}
if (m_recv_window.data_size + payload.size() > m_recv_window.window->size())
if (m_recv_window.data_size + payload.size() > m_recv_window.buffer->size())
{
dwarnln("Cannot fit received bytes to window");
dprintln_if(DEBUG_TCP, "Cannot fit received bytes to window, waiting for retransmission");
break;
}
auto* buffer = reinterpret_cast<uint8_t*>(m_recv_window.window->vaddr());
auto* buffer = reinterpret_cast<uint8_t*>(m_recv_window.buffer->vaddr());
memcpy(buffer + m_recv_window.data_size, payload.data(), payload.size());
m_recv_window.data_size += payload.size();
@ -393,13 +390,14 @@ namespace Kernel
dprintln_if(DEBUG_TCP, "Received {} bytes", payload.size());
}
break;
}
case State::LastAck:
if (!header.ack)
break;
set_connection_as_closed();
dprintln_if(DEBUG_TCP, "Got final ACK");
set_connection_as_closed();
break;
case State::Listen: ASSERT_NOT_REACHED();
case State::SynReceived: ASSERT_NOT_REACHED();
@ -426,7 +424,7 @@ namespace Kernel
void TCPSocket::process_task()
{
// FIXME: this should be dynamic
static constexpr uint32_t retransmit_timeout_ms = 100;
static constexpr uint32_t retransmit_timeout_ms = 1000;
BAN::RefPtr<TCPSocket> keep_alive = this;
@ -434,13 +432,13 @@ namespace Kernel
{
uint64_t current_ms = SystemTimer::get().ms_since_boot();
if (m_state == State::TimeWait && current_ms >= m_time_wait_start_ms + 6'000)
if (m_state == State::TimeWait && current_ms >= m_time_wait_start_ms + 30'000)
set_connection_as_closed();
{
LockGuard _(m_lock);
if (m_should_ack || m_recv_window.start_seq + m_recv_window.data_size != m_recv_window.ack_number)
if (m_should_ack)
{
m_should_ack = false;
@ -448,49 +446,28 @@ namespace Kernel
auto* target_address = reinterpret_cast<const sockaddr*>(&m_connection_info->address);
auto target_address_len = m_connection_info->address_len;
m_recv_window.ack_number = m_recv_window.start_seq + m_recv_window.data_size;
if (auto ret = m_network_layer.sendto(*this, {}, target_address, target_address_len); ret.is_error())
dwarnln("{}", ret.error());
continue;
}
bool is_send_open = false;
switch (m_state)
if (m_send_window.data_size > 0 && m_send_window.current_ack - m_send_window.has_ghost_byte > m_send_window.start_seq)
{
case State::Listen:
case State::Established:
case State::CloseWait:
case State::LastAck:
is_send_open = true;
break;
case State::SynSent:
case State::SynReceived:
case State::FinWait1:
case State::FinWait2:
case State::TimeWait:
case State::Closed:
is_send_open = false;
break;
case State::Closing: ASSERT_NOT_REACHED();
}
if (is_send_open && m_send_window.ack_number > m_send_window.start_seq)
{
uint32_t acknowledged_bytes = m_send_window.ack_number - m_send_window.start_seq;
ASSERT(acknowledged_bytes <= m_send_window.data_size);
uint32_t acknowledged_bytes = m_send_window.current_ack - m_send_window.start_seq - m_send_window.has_ghost_byte;
ASSERT_LTE(acknowledged_bytes, m_send_window.data_size);
m_send_window.data_size -= acknowledged_bytes;
m_send_window.start_seq += acknowledged_bytes;
if (m_send_window.data_size > 0)
{
auto* send_buffer = reinterpret_cast<uint8_t*>(m_send_window.window->vaddr());
auto* send_buffer = reinterpret_cast<uint8_t*>(m_send_window.buffer->vaddr());
memmove(send_buffer, send_buffer + acknowledged_bytes, m_send_window.data_size);
}
else
{
m_send_window.send_time_ms = 0;
m_send_window.last_send_ms = 0;
}
dprintln_if(DEBUG_TCP, "Target acknowledged {} bytes", acknowledged_bytes);
@ -498,20 +475,20 @@ namespace Kernel
continue;
}
if (is_send_open && m_send_window.data_size > 0 && current_ms >= m_send_window.send_time_ms + retransmit_timeout_ms)
if (m_send_window.data_size > 0 && current_ms >= m_send_window.last_send_ms + retransmit_timeout_ms)
{
ASSERT(m_connection_info.has_value());
auto* target_address = reinterpret_cast<const sockaddr*>(&m_connection_info->address);
auto target_address_len = m_connection_info->address_len;
const uint32_t total_send = BAN::Math::min<uint32_t>(m_send_window.data_size, m_send_window.size << m_send_window.scale);
const uint32_t total_send = BAN::Math::min<uint32_t>(m_send_window.data_size, m_send_window.scaled_size());
m_send_window.current_seq = m_send_window.start_seq;
auto* send_buffer = reinterpret_cast<const uint8_t*>(m_send_window.window->vaddr());
auto* send_buffer = reinterpret_cast<const uint8_t*>(m_send_window.buffer->vaddr());
for (uint32_t i = 0; i < total_send;)
{
uint32_t to_send = BAN::Math::min(total_send - i, m_send_window.mss);
const uint32_t to_send = BAN::Math::min(total_send - i, m_send_window.mss);
auto message = BAN::ConstByteSpan(send_buffer + i, to_send);
@ -527,7 +504,7 @@ namespace Kernel
i += to_send;
}
m_send_window.send_time_ms = current_ms;
m_send_window.last_send_ms = current_ms;
continue;
}
@ -571,7 +548,7 @@ namespace Kernel
uint32_t to_recv = BAN::Math::min<uint32_t>(buffer.size(), m_recv_window.data_size);
auto* recv_buffer = reinterpret_cast<uint8_t*>(m_recv_window.window->vaddr());
auto* recv_buffer = reinterpret_cast<uint8_t*>(m_recv_window.buffer->vaddr());
memcpy(buffer.data(), recv_buffer, to_recv);
m_recv_window.data_size -= to_recv;
@ -582,20 +559,28 @@ namespace Kernel
return to_recv;
}
BAN::ErrorOr<size_t> TCPSocket::sendto_impl(BAN::ConstByteSpan message, const sockaddr* address, socklen_t)
BAN::ErrorOr<size_t> TCPSocket::sendto_impl(BAN::ConstByteSpan message, const sockaddr* address, socklen_t address_len)
{
if (address)
return BAN::Error::from_errno(EISCONN);
if (message.size() > m_send_window.window->size())
return BAN::Error::from_errno(EMSGSIZE);
if (message.size() > m_send_window.buffer->size())
{
for (size_t i = 0; i < message.size(); i++)
{
const size_t to_send = BAN::Math::min<size_t>(message.size() - i, m_send_window.buffer->size());
TRY(sendto_impl(message.slice(i, to_send), address, address_len));
i += to_send;
}
return message.size();
}
LockGuard _(m_lock);
if (m_state == State::Closed)
return BAN::Error::from_errno(ENOTCONN);
while (m_send_window.data_size + message.size() > m_send_window.window->size())
while (true)
{
switch (m_state)
{
@ -614,12 +599,15 @@ namespace Kernel
case State::Closing: ASSERT_NOT_REACHED();
};
if (m_send_window.data_size + message.size() <= m_send_window.buffer->size())
break;
LockFreeGuard free(m_lock);
TRY(Thread::current().block_or_eintr_indefinite(m_semaphore));
}
{
auto* buffer = reinterpret_cast<uint8_t*>(m_send_window.window->vaddr());
auto* buffer = reinterpret_cast<uint8_t*>(m_send_window.buffer->vaddr());
memcpy(buffer + m_send_window.data_size, message.data(), message.size());
m_send_window.data_size += message.size();
}