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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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12
Kernel/Net/Routing.cpp
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@ -135,11 +135,11 @@ SpinlockProtected<Route::RouteList, LockRank::None>& routing_table()
return *s_routing_table;
}
ErrorOr<void> update_routing_table(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, LockRefPtr<NetworkAdapter> adapter, UpdateTable update)
ErrorOr<void> update_routing_table(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, RefPtr<NetworkAdapter> adapter, UpdateTable update)
{
dbgln_if(ROUTING_DEBUG, "update_routing_table {} {} {} {} {} {}", destination, gateway, netmask, flags, adapter, update == UpdateTable::Set ? "Set" : "Delete");
auto route_entry = adopt_lock_ref_if_nonnull(new (nothrow) Route { destination, gateway, netmask, flags, adapter.release_nonnull() });
auto route_entry = adopt_ref_if_nonnull(new (nothrow) Route { destination, gateway, netmask, flags, adapter.release_nonnull() });
if (!route_entry)
return ENOMEM;
@ -178,7 +178,7 @@ static MACAddress multicast_ethernet_address(IPv4Address const& address)
return MACAddress { 0x01, 0x00, 0x5e, (u8)(address[1] & 0x7f), address[2], address[3] };
}
RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, LockRefPtr<NetworkAdapter> const through, AllowUsingGateway allow_using_gateway)
RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, RefPtr<NetworkAdapter> const through, AllowUsingGateway allow_using_gateway)
{
auto matches = [&](auto& adapter) {
if (!through)
@ -200,8 +200,8 @@ RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, L
auto target_addr = target.to_u32();
auto source_addr = source.to_u32();
LockRefPtr<NetworkAdapter> local_adapter = nullptr;
LockRefPtr<Route> chosen_route = nullptr;
RefPtr<NetworkAdapter> local_adapter = nullptr;
RefPtr<Route> chosen_route = nullptr;
NetworkingManagement::the().for_each([source_addr, &target_addr, &local_adapter, &matches, &through](NetworkAdapter& adapter) {
auto adapter_addr = adapter.ipv4_address().to_u32();
@ -263,7 +263,7 @@ RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, L
return { nullptr, {} };
}
LockRefPtr<NetworkAdapter> adapter = nullptr;
RefPtr<NetworkAdapter> adapter = nullptr;
IPv4Address next_hop_ip;
if (local_adapter) {