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Kernel/Net: Iron out the locking mechanism across the subsystem

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There is a big mix of LockRefPtrs all over the Networking subsystem, as
well as lots of room for improvements with our locking patterns, which
this commit will not pursue, but will give a good start for such work.

To deal with this situation, we change the following things:
- Creating instances of NetworkAdapter should always yield a non-locking
  NonnullRefPtr. Acquiring an instance from the NetworkingManagement
  should give a simple RefPtr,as giving LockRefPtr does not really
  protect from concurrency problems in such case.
- Since NetworkingManagement works with normal RefPtrs we should
  protect all instances of RefPtr<NetworkAdapter> with SpinlockProtected
  to ensure references are gone unexpectedly.
- Protect the so_error class member with a proper spinlock. This happens
  to be important because the clear_so_error() method lacked any proper
  locking measures. It also helps preventing a possible TOCTOU when we
  might do a more fine-grained locking in the Socket code, so this could
  be definitely a start for this.
- Change unnecessary LockRefPtr<PacketWithTimestamp> in the structure
  of OutgoingPacket to a simple RefPtr<PacketWithTimestamp> as the whole
  list should be MutexProtected.
This commit is contained in:
Liav A 2023-04-11 03:50:15 +03:00 • committed by Linus Groh
parent bd7d4513bf
commit 7c1f645e27
13 changed files with 93 additions and 83 deletions
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24
Kernel/Net/TCPSocket.cpp
View file

@ -202,7 +202,8 @@ ErrorOr<size_t> TCPSocket::protocol_receive(ReadonlyBytes raw_ipv4_packet, UserO
ErrorOr<size_t> TCPSocket::protocol_send(UserOrKernelBuffer const& data, size_t data_length)
{
RoutingDecision routing_decision = route_to(peer_address(), local_address(), bound_interface());
auto adapter = bound_interface().with([](auto& bound_device) -> RefPtr<NetworkAdapter> { return bound_device; });
RoutingDecision routing_decision = route_to(peer_address(), local_address(), adapter);
if (routing_decision.is_zero())
return set_so_error(EHOSTUNREACH);
size_t mss = routing_decision.adapter->mtu() - sizeof(IPv4Packet) - sizeof(TCPPacket);
@ -220,7 +221,8 @@ ErrorOr<void> TCPSocket::send_ack(bool allow_duplicate)
ErrorOr<void> TCPSocket::send_tcp_packet(u16 flags, UserOrKernelBuffer const* payload, size_t payload_size, RoutingDecision* user_routing_decision)
{
RoutingDecision routing_decision = user_routing_decision ? *user_routing_decision : route_to(peer_address(), local_address(), bound_interface());
auto adapter = bound_interface().with([](auto& bound_device) -> RefPtr<NetworkAdapter> { return bound_device; });
RoutingDecision routing_decision = user_routing_decision ? *user_routing_decision : route_to(peer_address(), local_address(), adapter);
if (routing_decision.is_zero())
return set_so_error(EHOSTUNREACH);
@ -409,13 +411,14 @@ NetworkOrdered<u16> TCPSocket::compute_tcp_checksum(IPv4Address const& source, I
ErrorOr<void> TCPSocket::protocol_bind()
{
if (has_specific_local_address() && !m_adapter) {
m_adapter = NetworkingManagement::the().from_ipv4_address(local_address());
if (!m_adapter)
return set_so_error(EADDRNOTAVAIL);
}
return {};
return 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 {};
});
}
ErrorOr<void> TCPSocket::protocol_listen(bool did_allocate_port)
@ -598,7 +601,8 @@ void TCPSocket::retransmit_packets()
return;
}
auto routing_decision = route_to(peer_address(), local_address(), bound_interface());
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;