1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #pragma once
18
19 #include <android-base/thread_annotations.h>
20 #include <android/multinetwork.h>
21
22
23 #include "NetdConstants.h"
24 #include "Permission.h"
25 #include "PhysicalNetwork.h"
26 #include "UnreachableNetwork.h"
27 #include "android/net/INetd.h"
28 #include "netdutils/DumpWriter.h"
29
30 #include <sys/types.h>
31 #include <list>
32 #include <map>
33 #include <set>
34 #include <shared_mutex>
35 #include <unordered_map>
36 #include <unordered_set>
37 #include <vector>
38
39 struct android_net_context;
40
41 namespace android::net {
42
43 typedef std::shared_lock<std::shared_mutex> ScopedRLock;
44 typedef std::lock_guard<std::shared_mutex> ScopedWLock;
45
46 constexpr uint32_t kHandleMagic = 0xcafed00d;
47
48 // Utility to convert from netId to net_handle_t. Doing this here as opposed to exporting
49 // from net.c as it may have NDK implications. Besides no conversion available in net.c for
50 // obtaining handle given netId.
51 // TODO: Use getnetidfromhandle() in net.c.
netHandleToNetId(net_handle_t fromNetHandle)52 static inline unsigned netHandleToNetId(net_handle_t fromNetHandle) {
53 const uint32_t k32BitMask = 0xffffffff;
54 // This value MUST be kept in sync with the corresponding value in
55 // the android.net.Network#getNetworkHandle() implementation.
56
57 // Check for minimum acceptable version of the API in the low bits.
58 if (fromNetHandle != NETWORK_UNSPECIFIED &&
59 (fromNetHandle & k32BitMask) != kHandleMagic) {
60 return 0;
61 }
62
63 return ((fromNetHandle >> (CHAR_BIT * sizeof(k32BitMask))) & k32BitMask);
64 }
65
66 // Utility to convert from nethandle to netid, keep in sync with getNetworkHandle
67 // in Network.java.
netIdToNetHandle(unsigned fromNetId)68 static inline net_handle_t netIdToNetHandle(unsigned fromNetId) {
69 if (!fromNetId) {
70 return NETWORK_UNSPECIFIED;
71 }
72 return (((net_handle_t)fromNetId << 32) | kHandleMagic);
73 }
74
75 class Network;
76 class UidRanges;
77 class VirtualNetwork;
78
79 /*
80 * Keeps track of default, per-pid, and per-uid-range network selection, as
81 * well as the mark associated with each network. Networks are identified
82 * by netid. In all set* commands netid == 0 means "unspecified" and is
83 * equivalent to clearing the mapping.
84 */
85 class NetworkController {
86 public:
87 // NetIds 53..98 are reserved for future use.
88 static constexpr int MIN_OEM_ID = 1;
89 static constexpr int MAX_OEM_ID = 50;
90 static constexpr int LOCAL_NET_ID = INetd::LOCAL_NET_ID;
91 static constexpr int DUMMY_NET_ID = INetd::DUMMY_NET_ID;
92 static constexpr int UNREACHABLE_NET_ID = INetd::UNREACHABLE_NET_ID;
93
94 // Route mode for modify route
95 enum RouteOperation { ROUTE_ADD, ROUTE_UPDATE, ROUTE_REMOVE };
96
97 NetworkController();
98
99 unsigned getDefaultNetwork() const;
100 [[nodiscard]] int setDefaultNetwork(unsigned netId);
101
102 unsigned getNetworkForUser(uid_t uid) const;
103 unsigned getNetworkForConnect(uid_t uid) const;
104 void getNetworkContext(unsigned netId, uid_t uid, struct android_net_context* netcontext) const;
105 unsigned getNetworkForInterface(const char* interface) const;
106 bool isVirtualNetwork(unsigned netId) const;
107
108 [[nodiscard]] int createPhysicalNetwork(unsigned netId, Permission permission);
109 [[nodiscard]] int createPhysicalOemNetwork(Permission permission, unsigned* netId);
110 [[nodiscard]] int createVirtualNetwork(unsigned netId, bool secure, NativeVpnType vpnType);
111 [[nodiscard]] int destroyNetwork(unsigned netId);
112
113 [[nodiscard]] int addInterfaceToNetwork(unsigned netId, const char* interface);
114 [[nodiscard]] int removeInterfaceFromNetwork(unsigned netId, const char* interface);
115
116 Permission getPermissionForUser(uid_t uid) const;
117 void setPermissionForUsers(Permission permission, const std::vector<uid_t>& uids);
118 int checkUserNetworkAccess(uid_t uid, unsigned netId) const;
119 [[nodiscard]] int setPermissionForNetworks(Permission permission,
120 const std::vector<unsigned>& netIds);
121
122 [[nodiscard]] int addUsersToNetwork(unsigned netId, const UidRanges& uidRanges,
123 uint32_t subPriority);
124 [[nodiscard]] int removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges,
125 uint32_t subPriority);
126
127 // |nexthop| can be NULL (to indicate a directly-connected route), "unreachable" (to indicate a
128 // route that's blocked), "throw" (to indicate the lack of a match), or a regular IP address.
129 //
130 // Routes are added to tables determined by the interface, so only |interface| is actually used.
131 // |netId| is given only to sanity check that the interface has the correct netId.
132 [[nodiscard]] int addRoute(unsigned netId, const char* interface, const char* destination,
133 const char* nexthop, bool legacy, uid_t uid, int mtu);
134 [[nodiscard]] int updateRoute(unsigned netId, const char* interface, const char* destination,
135 const char* nexthop, bool legacy, uid_t uid, int mtu);
136 [[nodiscard]] int removeRoute(unsigned netId, const char* interface, const char* destination,
137 const char* nexthop, bool legacy, uid_t uid);
138
139 // Notes that the specified address has appeared on the specified interface.
140 void addInterfaceAddress(unsigned ifIndex, const char* address);
141 // Notes that the specified address has been removed from the specified interface.
142 // Returns true if we should destroy sockets on this address.
143 bool removeInterfaceAddress(unsigned ifIndex, const char* address);
144
145 bool canProtect(uid_t uid) const;
146 void allowProtect(const std::vector<uid_t>& uids);
147 void denyProtect(const std::vector<uid_t>& uids);
148
149 void dump(netdutils::DumpWriter& dw);
150
151 private:
152 bool isValidNetworkLocked(unsigned netId) const;
153 Network* getNetworkLocked(unsigned netId) const;
154
155 // Sets |*netId| to an appropriate NetId to use for DNS for the given user. Call with |*netId|
156 // set to a non-NETID_UNSET value if the user already has indicated a preference. Returns the
157 // fwmark value to set on the socket when performing the DNS request.
158 uint32_t getNetworkForDnsLocked(unsigned* netId, uid_t uid) const;
159 unsigned getNetworkForConnectLocked(uid_t uid) const;
160 unsigned getNetworkForInterfaceLocked(const char* interface) const;
161 bool canProtectLocked(uid_t uid) const;
162 bool isVirtualNetworkLocked(unsigned netId) const;
163 VirtualNetwork* getVirtualNetworkForUserLocked(uid_t uid) const;
164 Network* getPhysicalOrUnreachableNetworkForUserLocked(uid_t uid) const;
165 Permission getPermissionForUserLocked(uid_t uid) const;
166 int checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const;
167 [[nodiscard]] int createPhysicalNetworkLocked(unsigned netId, Permission permission);
168
169 [[nodiscard]] int modifyRoute(unsigned netId, const char* interface, const char* destination,
170 const char* nexthop, RouteOperation op, bool legacy, uid_t uid,
171 int mtu);
172 [[nodiscard]] int modifyFallthroughLocked(unsigned vpnNetId, bool add);
173 void updateTcpSocketMonitorPolling();
174
175 class DelegateImpl;
176 DelegateImpl* const mDelegateImpl;
177
178 // mRWLock guards all accesses to mDefaultNetId, mNetworks, mUsers, mProtectableUsers,
179 // mIfindexToLastNetId and mAddressToIfindices.
180 mutable std::shared_mutex mRWLock;
181 unsigned mDefaultNetId;
182 std::map<unsigned, Network*> mNetworks; // Map keys are NetIds.
183 std::map<uid_t, Permission> mUsers;
184 std::set<uid_t> mProtectableUsers;
185 // Map interface (ifIndex) to its current NetId, or the last NetId if the interface was removed
186 // from the network and not added to another network. This state facilitates the interface to
187 // NetId lookup during RTM_DELADDR (NetworkController::removeInterfaceAddress), when the
188 // interface in question might already have been removed from the network.
189 // An interface is added to this map when it is added to a network and removed from this map
190 // when its network is destroyed.
191 std::unordered_map<unsigned, unsigned> mIfindexToLastNetId;
192 // Map IP address to the list of active interfaces (ifIndex) that have that address.
193 // Also contains IP addresses configured on interfaces that have not been added to any network.
194 // TODO: Does not track IP addresses present when netd is started or restarts after a crash.
195 // This is not a problem for its intended use (tracking IP addresses on VPN interfaces), but
196 // we should fix it.
197 std::unordered_map<std::string, std::unordered_set<unsigned>> mAddressToIfindices;
198
199 };
200
201 } // namespace android::net
202