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- /*
- * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- #include <AK/HashMap.h>
- #include <AK/Singleton.h>
- #include <Kernel/Debug.h>
- #include <Kernel/Net/LoopbackAdapter.h>
- #include <Kernel/Net/Routing.h>
- #include <Kernel/Thread.h>
- namespace Kernel {
- static AK::Singleton<Lockable<HashMap<IPv4Address, MACAddress>>> s_arp_table;
- class ARPTableBlocker : public Thread::Blocker {
- public:
- ARPTableBlocker(IPv4Address ip_addr, Optional<MACAddress>& addr);
- virtual const char* state_string() const override { return "Routing (ARP)"; }
- virtual Type blocker_type() const override { return Type::Routing; }
- virtual bool should_block() override { return m_should_block; }
- virtual void not_blocking(bool) override;
- bool unblock(bool from_add_blocker, const IPv4Address& ip_addr, const MACAddress& addr)
- {
- if (m_ip_addr != ip_addr)
- return false;
- {
- ScopedSpinLock lock(m_lock);
- if (m_did_unblock)
- return false;
- m_did_unblock = true;
- m_addr = addr;
- }
- if (!from_add_blocker)
- unblock_from_blocker();
- return true;
- }
- const IPv4Address& ip_addr() const { return m_ip_addr; }
- private:
- const IPv4Address m_ip_addr;
- Optional<MACAddress>& m_addr;
- bool m_did_unblock { false };
- bool m_should_block { true };
- };
- class ARPTableBlockCondition : public Thread::BlockCondition {
- public:
- void unblock(const IPv4Address& ip_addr, const MACAddress& addr)
- {
- BlockCondition::unblock([&](auto& b, void*, bool&) {
- VERIFY(b.blocker_type() == Thread::Blocker::Type::Routing);
- auto& blocker = static_cast<ARPTableBlocker&>(b);
- return blocker.unblock(false, ip_addr, addr);
- });
- }
- protected:
- virtual bool should_add_blocker(Thread::Blocker& b, void*) override
- {
- VERIFY(b.blocker_type() == Thread::Blocker::Type::Routing);
- auto& blocker = static_cast<ARPTableBlocker&>(b);
- auto val = s_arp_table->resource().get(blocker.ip_addr());
- if (!val.has_value())
- return true;
- return blocker.unblock(true, blocker.ip_addr(), val.value());
- }
- };
- static AK::Singleton<ARPTableBlockCondition> s_arp_table_block_condition;
- ARPTableBlocker::ARPTableBlocker(IPv4Address ip_addr, Optional<MACAddress>& addr)
- : m_ip_addr(ip_addr)
- , m_addr(addr)
- {
- if (!set_block_condition(*s_arp_table_block_condition))
- m_should_block = false;
- }
- void ARPTableBlocker::not_blocking(bool timeout_in_past)
- {
- VERIFY(timeout_in_past || !m_should_block);
- auto addr = s_arp_table->resource().get(ip_addr());
- ScopedSpinLock lock(m_lock);
- if (!m_did_unblock) {
- m_did_unblock = true;
- m_addr = move(addr);
- }
- }
- Lockable<HashMap<IPv4Address, MACAddress>>& arp_table()
- {
- return *s_arp_table;
- }
- void update_arp_table(const IPv4Address& ip_addr, const MACAddress& addr)
- {
- LOCKER(arp_table().lock());
- arp_table().resource().set(ip_addr, addr);
- s_arp_table_block_condition->unblock(ip_addr, addr);
- dmesgln("ARP table ({} entries):", arp_table().resource().size());
- for (auto& it : arp_table().resource()) {
- dmesgln("{} :: {}", it.value.to_string(), it.key.to_string());
- }
- }
- bool RoutingDecision::is_zero() const
- {
- return adapter.is_null() || next_hop.is_zero();
- }
- RoutingDecision route_to(const IPv4Address& target, const IPv4Address& source, const RefPtr<NetworkAdapter> through)
- {
- auto matches = [&](auto& adapter) {
- if (!through)
- return true;
- return through == adapter;
- };
- auto if_matches = [&](auto& adapter, const auto& mac) -> RoutingDecision {
- if (!matches(adapter))
- return { nullptr, {} };
- return { adapter, mac };
- };
- if (target[0] == 127)
- return if_matches(LoopbackAdapter::the(), LoopbackAdapter::the().mac_address());
- auto target_addr = target.to_u32();
- auto source_addr = source.to_u32();
- RefPtr<NetworkAdapter> local_adapter = nullptr;
- RefPtr<NetworkAdapter> gateway_adapter = nullptr;
- NetworkAdapter::for_each([source_addr, &target_addr, &local_adapter, &gateway_adapter, &matches](auto& adapter) {
- auto adapter_addr = adapter.ipv4_address().to_u32();
- auto adapter_mask = adapter.ipv4_netmask().to_u32();
- if (source_addr != 0 && source_addr != adapter_addr)
- return;
- if ((target_addr & adapter_mask) == (adapter_addr & adapter_mask) && matches(adapter))
- local_adapter = adapter;
- if (adapter.ipv4_gateway().to_u32() != 0 && matches(adapter))
- gateway_adapter = adapter;
- });
- if (local_adapter && target == local_adapter->ipv4_address())
- return { local_adapter, local_adapter->mac_address() };
- if (!local_adapter && !gateway_adapter) {
- dbgln_if(ROUTING_DEBUG, "Routing: Couldn't find a suitable adapter for route to {}", target);
- return { nullptr, {} };
- }
- RefPtr<NetworkAdapter> adapter = nullptr;
- IPv4Address next_hop_ip;
- if (local_adapter) {
- dbgln_if(ROUTING_DEBUG, "Routing: Got adapter for route (direct): {} ({}/{}) for {}",
- local_adapter->name(),
- local_adapter->ipv4_address(),
- local_adapter->ipv4_netmask(),
- target);
- adapter = local_adapter;
- next_hop_ip = target;
- } else if (gateway_adapter) {
- dbgln_if(ROUTING_DEBUG, "Routing: Got adapter for route (using gateway {}): {} ({}/{}) for {}",
- gateway_adapter->ipv4_gateway(),
- gateway_adapter->name(),
- gateway_adapter->ipv4_address(),
- gateway_adapter->ipv4_netmask(),
- target);
- adapter = gateway_adapter;
- next_hop_ip = gateway_adapter->ipv4_gateway();
- } else {
- return { nullptr, {} };
- }
- // If it's a broadcast, we already know everything we need to know.
- // FIXME: We should also deal with the case where `target_addr` is
- // a broadcast to a subnet rather than a full broadcast.
- if (target_addr == 0xffffffff && matches(adapter))
- return { adapter, { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } };
- {
- LOCKER(arp_table().lock());
- auto addr = arp_table().resource().get(next_hop_ip);
- if (addr.has_value()) {
- dbgln_if(ROUTING_DEBUG, "Routing: Using cached ARP entry for {} ({})", next_hop_ip, addr.value().to_string());
- return { adapter, addr.value() };
- }
- }
- dbgln_if(ROUTING_DEBUG, "Routing: Sending ARP request via adapter {} for IPv4 address {}", adapter->name(), next_hop_ip);
- ARPPacket request;
- request.set_operation(ARPOperation::Request);
- request.set_target_hardware_address({ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff });
- request.set_target_protocol_address(next_hop_ip);
- request.set_sender_hardware_address(adapter->mac_address());
- request.set_sender_protocol_address(adapter->ipv4_address());
- adapter->send({ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }, request);
- Optional<MACAddress> addr;
- if (!Thread::current()->block<ARPTableBlocker>({}, next_hop_ip, addr).was_interrupted()) {
- if (addr.has_value()) {
- dbgln_if(ROUTING_DEBUG, "Routing: Got ARP response using adapter {} for {} ({})",
- adapter->name(),
- next_hop_ip,
- addr.value().to_string());
- return { adapter, addr.value() };
- }
- }
- dbgln_if(ROUTING_DEBUG, "Routing: Couldn't find route using adapter {} for {}", adapter->name(), target);
- return { nullptr, {} };
- }
- }
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