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 #ifndef NETD_SERVER_NETWORK_CONTROLLER_H
18 #define NETD_SERVER_NETWORK_CONTROLLER_H
19
20 #include <android-base/thread_annotations.h>
21 #include <android/multinetwork.h>
22
23
24 #include "NetdConstants.h"
25 #include "Permission.h"
26 #include "android/net/INetd.h"
27 #include "netdutils/DumpWriter.h"
28
29 #include <sys/types.h>
30 #include <list>
31 #include <map>
32 #include <set>
33 #include <shared_mutex>
34 #include <unordered_map>
35 #include <unordered_set>
36 #include <vector>
37
38 struct android_net_context;
39
40 namespace android {
41 namespace 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 52..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 = 51;
92
93 NetworkController();
94
95 unsigned getDefaultNetwork() const;
96 int setDefaultNetwork(unsigned netId) WARN_UNUSED_RESULT;
97
98 // Sets |*netId| to an appropriate NetId to use for DNS for the given user. Call with |*netId|
99 // set to a non-NETID_UNSET value if the user already has indicated a preference. Returns the
100 // fwmark value to set on the socket when performing the DNS request.
101 uint32_t getNetworkForDns(unsigned* netId, uid_t uid) const;
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 int createPhysicalNetwork(unsigned netId, Permission permission) WARN_UNUSED_RESULT;
109 int createPhysicalOemNetwork(Permission permission, unsigned *netId) WARN_UNUSED_RESULT;
110 int createVirtualNetwork(unsigned netId, bool secure) WARN_UNUSED_RESULT;
111 int destroyNetwork(unsigned netId) WARN_UNUSED_RESULT;
112
113 int addInterfaceToNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
114 int removeInterfaceFromNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
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 int setPermissionForNetworks(Permission permission,
120 const std::vector<unsigned>& netIds) WARN_UNUSED_RESULT;
121
122 int addUsersToNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
123 int removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
124
125 // |nexthop| can be NULL (to indicate a directly-connected route), "unreachable" (to indicate a
126 // route that's blocked), "throw" (to indicate the lack of a match), or a regular IP address.
127 //
128 // Routes are added to tables determined by the interface, so only |interface| is actually used.
129 // |netId| is given only to sanity check that the interface has the correct netId.
130 int addRoute(unsigned netId, const char* interface, const char* destination,
131 const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
132 int removeRoute(unsigned netId, const char* interface, const char* destination,
133 const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
134
135 // Notes that the specified address has appeared on the specified interface.
136 void addInterfaceAddress(unsigned ifIndex, const char* address);
137 // Notes that the specified address has been removed from the specified interface.
138 // Returns true if we should destroy sockets on this address.
139 bool removeInterfaceAddress(unsigned ifIndex, const char* address);
140
141 bool canProtect(uid_t uid) const;
142 void allowProtect(const std::vector<uid_t>& uids);
143 void denyProtect(const std::vector<uid_t>& uids);
144
145 void dump(netdutils::DumpWriter& dw);
146
147 private:
148 bool isValidNetworkLocked(unsigned netId) const;
149 Network* getNetworkLocked(unsigned netId) const;
150 uint32_t getNetworkForDnsLocked(unsigned* netId, uid_t uid) const;
151 unsigned getNetworkForUserLocked(uid_t uid) const;
152 unsigned getNetworkForConnectLocked(uid_t uid) const;
153 unsigned getNetworkForInterfaceLocked(const char* interface) const;
154 bool canProtectLocked(uid_t uid) const;
155 bool isVirtualNetworkLocked(unsigned netId) const;
156 VirtualNetwork* getVirtualNetworkForUserLocked(uid_t uid) const;
157 Permission getPermissionForUserLocked(uid_t uid) const;
158 int checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const;
159 int createPhysicalNetworkLocked(unsigned netId, Permission permission) WARN_UNUSED_RESULT;
160
161 int modifyRoute(unsigned netId, const char* interface, const char* destination,
162 const char* nexthop, bool add, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
163 int modifyFallthroughLocked(unsigned vpnNetId, bool add) WARN_UNUSED_RESULT;
164 void updateTcpSocketMonitorPolling();
165
166 class DelegateImpl;
167 DelegateImpl* const mDelegateImpl;
168
169 // mRWLock guards all accesses to mDefaultNetId, mNetworks, mUsers, mProtectableUsers,
170 // mIfindexToLastNetId and mAddressToIfindices.
171 mutable std::shared_mutex mRWLock;
172 unsigned mDefaultNetId;
173 std::map<unsigned, Network*> mNetworks; // Map keys are NetIds.
174 std::map<uid_t, Permission> mUsers;
175 std::set<uid_t> mProtectableUsers;
176 // Map interface (ifIndex) to its current NetId, or the last NetId if the interface was removed
177 // from the network and not added to another network. This state facilitates the interface to
178 // NetId lookup during RTM_DELADDR (NetworkController::removeInterfaceAddress), when the
179 // interface in question might already have been removed from the network.
180 // An interface is added to this map when it is added to a network and removed from this map
181 // when its network is destroyed.
182 std::unordered_map<unsigned, unsigned> mIfindexToLastNetId;
183 // Map IP address to the list of active interfaces (ifIndex) that have that address.
184 // Also contains IP addresses configured on interfaces that have not been added to any network.
185 // TODO: Does not track IP addresses present when netd is started or restarts after a crash.
186 // This is not a problem for its intended use (tracking IP addresses on VPN interfaces), but
187 // we should fix it.
188 std::unordered_map<std::string, std::unordered_set<unsigned>> mAddressToIfindices;
189
190 };
191
192 } // namespace net
193 } // namespace android
194
195 #endif // NETD_SERVER_NETWORK_CONTROLLER_H
196