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/*
* Copyright (c) 2018-2020, 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/Net/LoopbackAdapter.h>
#include <Kernel/Net/Routing.h>
#include <Kernel/Thread.h>
//#define ROUTING_DEBUG
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&) {
ASSERT(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
{
ASSERT(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)
{
ASSERT(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);
klog() << "ARP table (" << arp_table().resource().size() << " entries):";
for (auto& it : arp_table().resource()) {
klog() << it.value.to_string().characters() << " :: " << it.key.to_string().characters();
}
}
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) {
#ifdef ROUTING_DEBUG
klog() << "Routing: Couldn't find a suitable adapter for route to " << target.to_string().characters();
#endif
return { nullptr, {} };
}
RefPtr<NetworkAdapter> adapter = nullptr;
IPv4Address next_hop_ip;
if (local_adapter) {
#ifdef ROUTING_DEBUG
klog() << "Routing: Got adapter for route (direct): " << local_adapter->name().characters() << " (" << local_adapter->ipv4_address().to_string().characters() << "/" << local_adapter->ipv4_netmask().to_string().characters() << ") for " << target.to_string().characters();
#endif
adapter = local_adapter;
next_hop_ip = target;
} else if (gateway_adapter) {
#ifdef ROUTING_DEBUG
klog() << "Routing: Got adapter for route (using gateway " << gateway_adapter->ipv4_gateway().to_string().characters() << "): " << gateway_adapter->name().characters() << " (" << gateway_adapter->ipv4_address().to_string().characters() << "/" << gateway_adapter->ipv4_netmask().to_string().characters() << ") for " << target.to_string().characters();
#endif
adapter = gateway_adapter;
next_hop_ip = gateway_adapter->ipv4_gateway();
} else {
return { nullptr, {} };
}
{
LOCKER(arp_table().lock());
auto addr = arp_table().resource().get(next_hop_ip);
if (addr.has_value()) {
#ifdef ROUTING_DEBUG
klog() << "Routing: Using cached ARP entry for " << next_hop_ip.to_string().characters() << " (" << addr.value().to_string().characters() << ")";
#endif
return { adapter, addr.value() };
}
}
#ifdef ROUTING_DEBUG
klog() << "Routing: Sending ARP request via adapter " << adapter->name().characters() << " for IPv4 address " << next_hop_ip.to_string().characters();
#endif
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()) {
#ifdef ROUTING_DEBUG
klog() << "Routing: Got ARP response using adapter " << adapter->name().characters() << " for " << next_hop_ip.to_string().characters() << " (" << addr.value().to_string().characters() << ")";
#endif
return { adapter, addr.value() };
}
}
#ifdef ROUTING_DEBUG
klog() << "Routing: Couldn't find route using adapter " << adapter->name().characters() << " for " << target.to_string().characters();
#endif
return { nullptr, {} };
}
}
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