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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <AK/HashMap.h>
28#include <Kernel/Net/LoopbackAdapter.h>
29#include <Kernel/Net/Routing.h>
30#include <Kernel/Thread.h>
31
32//#define ROUTING_DEBUG
33
34namespace Kernel {
35
36Lockable<HashMap<IPv4Address, MACAddress>>& arp_table()
37{
38 static Lockable<HashMap<IPv4Address, MACAddress>>* the;
39 if (!the)
40 the = new Lockable<HashMap<IPv4Address, MACAddress>>;
41 return *the;
42}
43
44bool RoutingDecision::is_zero() const
45{
46 return adapter.is_null() || next_hop.is_zero();
47}
48
49RoutingDecision route_to(const IPv4Address& target, const IPv4Address& source, const RefPtr<NetworkAdapter> through)
50{
51 auto matches = [&](auto& adapter) {
52 if (!through)
53 return true;
54
55 return through == adapter;
56 };
57 auto if_matches = [&](auto& adapter, const auto& mac) -> RoutingDecision {
58 if (!matches(adapter))
59 return { nullptr, {} };
60 return { adapter, mac };
61 };
62
63 if (target[0] == 127)
64 return if_matches(LoopbackAdapter::the(), LoopbackAdapter::the().mac_address());
65
66 auto target_addr = target.to_u32();
67 auto source_addr = source.to_u32();
68
69 RefPtr<NetworkAdapter> local_adapter = nullptr;
70 RefPtr<NetworkAdapter> gateway_adapter = nullptr;
71
72 NetworkAdapter::for_each([source_addr, &target_addr, &local_adapter, &gateway_adapter, &matches](auto& adapter) {
73 auto adapter_addr = adapter.ipv4_address().to_u32();
74 auto adapter_mask = adapter.ipv4_netmask().to_u32();
75
76 if (source_addr != 0 && source_addr != adapter_addr)
77 return;
78
79 if ((target_addr & adapter_mask) == (adapter_addr & adapter_mask) && matches(adapter))
80 local_adapter = adapter;
81
82 if (adapter.ipv4_gateway().to_u32() != 0 && matches(adapter))
83 gateway_adapter = adapter;
84 });
85
86 if (local_adapter && target == local_adapter->ipv4_address())
87 return { local_adapter, local_adapter->mac_address() };
88
89 if (!local_adapter && !gateway_adapter) {
90#ifdef ROUTING_DEBUG
91 klog() << "Routing: Couldn't find a suitable adapter for route to " << target.to_string().characters();
92#endif
93 return { nullptr, {} };
94 }
95
96 RefPtr<NetworkAdapter> adapter = nullptr;
97 IPv4Address next_hop_ip;
98
99 if (local_adapter) {
100#ifdef ROUTING_DEBUG
101 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();
102#endif
103 adapter = local_adapter;
104 next_hop_ip = target;
105 } else if (gateway_adapter) {
106#ifdef ROUTING_DEBUG
107 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();
108#endif
109 adapter = gateway_adapter;
110 next_hop_ip = gateway_adapter->ipv4_gateway();
111 } else {
112 return { nullptr, {} };
113 }
114
115 {
116 LOCKER(arp_table().lock());
117 auto addr = arp_table().resource().get(next_hop_ip);
118 if (addr.has_value()) {
119#ifdef ROUTING_DEBUG
120 klog() << "Routing: Using cached ARP entry for " << next_hop_ip.to_string().characters() << " (" << addr.value().to_string().characters() << ")";
121#endif
122 return { adapter, addr.value() };
123 }
124 }
125
126#ifdef ROUTING_DEBUG
127 klog() << "Routing: Sending ARP request via adapter " << adapter->name().characters() << " for IPv4 address " << next_hop_ip.to_string().characters();
128#endif
129
130 ARPPacket request;
131 request.set_operation(ARPOperation::Request);
132 request.set_target_hardware_address({ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff });
133 request.set_target_protocol_address(next_hop_ip);
134 request.set_sender_hardware_address(adapter->mac_address());
135 request.set_sender_protocol_address(adapter->ipv4_address());
136 adapter->send({ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }, request);
137
138 (void)Thread::current->block_until("Routing (ARP)", [next_hop_ip] {
139 return arp_table().resource().get(next_hop_ip).has_value();
140 });
141
142 {
143 LOCKER(arp_table().lock());
144 auto addr = arp_table().resource().get(next_hop_ip);
145 if (addr.has_value()) {
146#ifdef ROUTING_DEBUG
147 klog() << "Routing: Got ARP response using adapter " << adapter->name().characters() << " for " << next_hop_ip.to_string().characters() << " (" << addr.value().to_string().characters() << ")";
148#endif
149 return { adapter, addr.value() };
150 }
151 }
152
153#ifdef ROUTING_DEBUG
154 klog() << "Routing: Couldn't find route using adapter " << adapter->name().characters() << " for " << target.to_string().characters();
155#endif
156
157 return { nullptr, {} };
158}
159
160}