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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/NetworkingManagement.h
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@ -8,9 +8,9 @@
#include <AK/Function.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/RefPtr.h>
#include <AK/Types.h>
#include <Kernel/Bus/PCI/Definitions.h>
#include <Kernel/Library/NonnullLockRefPtr.h>
#include <Kernel/Locking/SpinlockProtected.h>
#include <Kernel/Memory/Region.h>
#include <Kernel/Net/NetworkAdapter.h>
@ -33,16 +33,16 @@ public:
void for_each(Function<void(NetworkAdapter&)>);
ErrorOr<void> try_for_each(Function<ErrorOr<void>(NetworkAdapter&)>);
LockRefPtr<NetworkAdapter> from_ipv4_address(IPv4Address const&) const;
LockRefPtr<NetworkAdapter> lookup_by_name(StringView) const;
RefPtr<NetworkAdapter> from_ipv4_address(IPv4Address const&) const;
RefPtr<NetworkAdapter> lookup_by_name(StringView) const;
NonnullLockRefPtr<NetworkAdapter> loopback_adapter() const;
NonnullRefPtr<NetworkAdapter> loopback_adapter() const;
private:
ErrorOr<NonnullRefPtr<NetworkAdapter>> determine_network_device(PCI::DeviceIdentifier const&) const;
SpinlockProtected<Vector<NonnullLockRefPtr<NetworkAdapter>>, LockRank::None> m_adapters {};
LockRefPtr<NetworkAdapter> m_loopback_adapter;
SpinlockProtected<Vector<NonnullRefPtr<NetworkAdapter>>, LockRank::None> m_adapters {};
RefPtr<NetworkAdapter> m_loopback_adapter;
};
}