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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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14
Kernel/Net/Routing.h
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@ -7,7 +7,7 @@
#pragma once
#include <AK/IPv4Address.h>
#include <Kernel/Library/NonnullLockRefPtr.h>
#include <AK/RefPtr.h>
#include <Kernel/Locking/MutexProtected.h>
#include <Kernel/Net/NetworkAdapter.h>
#include <Kernel/Thread.h>
@ -15,7 +15,7 @@
namespace Kernel {
struct Route final : public AtomicRefCounted<Route> {
Route(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, NonnullLockRefPtr<NetworkAdapter> adapter)
Route(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, NonnullRefPtr<NetworkAdapter> adapter)
: destination(destination)
, gateway(gateway)
, netmask(netmask)
@ -38,14 +38,14 @@ struct Route final : public AtomicRefCounted<Route> {
const IPv4Address gateway;
const IPv4Address netmask;
const u16 flags;
NonnullLockRefPtr<NetworkAdapter> adapter;
NonnullRefPtr<NetworkAdapter> const adapter;
IntrusiveListNode<Route, LockRefPtr<Route>> route_list_node {};
IntrusiveListNode<Route, RefPtr<Route>> route_list_node {};
using RouteList = IntrusiveList<&Route::route_list_node>;
};
struct RoutingDecision {
LockRefPtr<NetworkAdapter> adapter;
RefPtr<NetworkAdapter> adapter;
MACAddress next_hop;
bool is_zero() const;
@ -57,14 +57,14 @@ enum class UpdateTable {
};
void update_arp_table(IPv4Address const&, MACAddress const&, UpdateTable update);
ErrorOr<void> update_routing_table(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, LockRefPtr<NetworkAdapter> const adapter, UpdateTable update);
ErrorOr<void> update_routing_table(IPv4Address const& destination, IPv4Address const& gateway, IPv4Address const& netmask, u16 flags, RefPtr<NetworkAdapter> const adapter, UpdateTable update);
enum class AllowUsingGateway {
Yes,
No,
};
RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, LockRefPtr<NetworkAdapter> const through = nullptr, AllowUsingGateway = AllowUsingGateway::Yes);
RoutingDecision route_to(IPv4Address const& target, IPv4Address const& source, RefPtr<NetworkAdapter> const through = nullptr, AllowUsingGateway = AllowUsingGateway::Yes);
SpinlockProtected<HashMap<IPv4Address, MACAddress>, LockRank::None>& arp_table();
SpinlockProtected<Route::RouteList, LockRank::None>& routing_table();