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 "android/net/INetd.h"
26 #include "netdutils/DumpWriter.h"
27
28 #include <sys/types.h>
29 #include <list>
30 #include <map>
31 #include <set>
32 #include <shared_mutex>
33 #include <unordered_map>
34 #include <unordered_set>
35 #include <vector>
36
37 struct android_net_context;
38
39 namespace android::net {
40
41 typedef std::shared_lock<std::shared_mutex> ScopedRLock;
42 typedef std::lock_guard<std::shared_mutex> ScopedWLock;
43
44 constexpr uint32_t kHandleMagic = 0xcafed00d;
45
46 // Utility to convert from netId to net_handle_t. Doing this here as opposed to exporting
47 // from net.c as it may have NDK implications. Besides no conversion available in net.c for
48 // obtaining handle given netId.
49 // TODO: Use getnetidfromhandle() in net.c.
netHandleToNetId(net_handle_t fromNetHandle)50 static inline unsigned netHandleToNetId(net_handle_t fromNetHandle) {
51 const uint32_t k32BitMask = 0xffffffff;
52 // This value MUST be kept in sync with the corresponding value in
53 // the android.net.Network#getNetworkHandle() implementation.
54
55 // Check for minimum acceptable version of the API in the low bits.
56 if (fromNetHandle != NETWORK_UNSPECIFIED &&
57 (fromNetHandle & k32BitMask) != kHandleMagic) {
58 return 0;
59 }
60
61 return ((fromNetHandle >> (CHAR_BIT * sizeof(k32BitMask))) & k32BitMask);
62 }
63
64 // Utility to convert from nethandle to netid, keep in sync with getNetworkHandle
65 // in Network.java.
netIdToNetHandle(unsigned fromNetId)66 static inline net_handle_t netIdToNetHandle(unsigned fromNetId) {
67 if (!fromNetId) {
68 return NETWORK_UNSPECIFIED;
69 }
70 return (((net_handle_t)fromNetId << 32) | kHandleMagic);
71 }
72
73 class Network;
74 class UidRanges;
75 class VirtualNetwork;
76
77 /*
78 * Keeps track of default, per-pid, and per-uid-range network selection, as
79 * well as the mark associated with each network. Networks are identified
80 * by netid. In all set* commands netid == 0 means "unspecified" and is
81 * equivalent to clearing the mapping.
82 */
83 class NetworkController {
84 public:
85 // NetIds 52..98 are reserved for future use.
86 static constexpr int MIN_OEM_ID = 1;
87 static constexpr int MAX_OEM_ID = 50;
88 static constexpr int LOCAL_NET_ID = INetd::LOCAL_NET_ID;
89 static constexpr int DUMMY_NET_ID = 51;
90
91 // Route mode for modify route
92 enum RouteOperation { ROUTE_ADD, ROUTE_UPDATE, ROUTE_REMOVE };
93
94 NetworkController();
95
96 unsigned getDefaultNetwork() const;
97 [[nodiscard]] int setDefaultNetwork(unsigned netId);
98
99 unsigned getNetworkForUser(uid_t uid) const;
100 unsigned getNetworkForConnect(uid_t uid) const;
101 void getNetworkContext(unsigned netId, uid_t uid, struct android_net_context* netcontext) const;
102 unsigned getNetworkForInterface(const char* interface) const;
103 bool isVirtualNetwork(unsigned netId) const;
104
105 [[nodiscard]] int createPhysicalNetwork(unsigned netId, Permission permission);
106 [[nodiscard]] int createPhysicalOemNetwork(Permission permission, unsigned* netId);
107 [[nodiscard]] int createVirtualNetwork(unsigned netId, bool secure);
108 [[nodiscard]] int destroyNetwork(unsigned netId);
109
110 [[nodiscard]] int addInterfaceToNetwork(unsigned netId, const char* interface);
111 [[nodiscard]] int removeInterfaceFromNetwork(unsigned netId, const char* interface);
112
113 Permission getPermissionForUser(uid_t uid) const;
114 void setPermissionForUsers(Permission permission, const std::vector<uid_t>& uids);
115 int checkUserNetworkAccess(uid_t uid, unsigned netId) const;
116 [[nodiscard]] int setPermissionForNetworks(Permission permission,
117 const std::vector<unsigned>& netIds);
118
119 [[nodiscard]] int addUsersToNetwork(unsigned netId, const UidRanges& uidRanges);
120 [[nodiscard]] int removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges);
121
122 // |nexthop| can be NULL (to indicate a directly-connected route), "unreachable" (to indicate a
123 // route that's blocked), "throw" (to indicate the lack of a match), or a regular IP address.
124 //
125 // Routes are added to tables determined by the interface, so only |interface| is actually used.
126 // |netId| is given only to sanity check that the interface has the correct netId.
127 [[nodiscard]] int addRoute(unsigned netId, const char* interface, const char* destination,
128 const char* nexthop, bool legacy, uid_t uid, int mtu);
129 [[nodiscard]] int updateRoute(unsigned netId, const char* interface, const char* destination,
130 const char* nexthop, bool legacy, uid_t uid, int mtu);
131 [[nodiscard]] int removeRoute(unsigned netId, const char* interface, const char* destination,
132 const char* nexthop, bool legacy, uid_t uid);
133
134 // Notes that the specified address has appeared on the specified interface.
135 void addInterfaceAddress(unsigned ifIndex, const char* address);
136 // Notes that the specified address has been removed from the specified interface.
137 // Returns true if we should destroy sockets on this address.
138 bool removeInterfaceAddress(unsigned ifIndex, const char* address);
139
140 bool canProtect(uid_t uid) const;
141 void allowProtect(const std::vector<uid_t>& uids);
142 void denyProtect(const std::vector<uid_t>& uids);
143
144 void dump(netdutils::DumpWriter& dw);
145
146 private:
147 bool isValidNetworkLocked(unsigned netId) const;
148 Network* getNetworkLocked(unsigned netId) const;
149
150 // Sets |*netId| to an appropriate NetId to use for DNS for the given user. Call with |*netId|
151 // set to a non-NETID_UNSET value if the user already has indicated a preference. Returns the
152 // fwmark value to set on the socket when performing the DNS request.
153 uint32_t getNetworkForDnsLocked(unsigned* netId, uid_t uid) const;
154
155 unsigned getNetworkForUserLocked(uid_t uid) const;
156 unsigned getNetworkForConnectLocked(uid_t uid) const;
157 unsigned getNetworkForInterfaceLocked(const char* interface) const;
158 bool canProtectLocked(uid_t uid) const;
159 bool isVirtualNetworkLocked(unsigned netId) const;
160 VirtualNetwork* getVirtualNetworkForUserLocked(uid_t uid) const;
161 Permission getPermissionForUserLocked(uid_t uid) const;
162 int checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const;
163 [[nodiscard]] int createPhysicalNetworkLocked(unsigned netId, Permission permission);
164
165 [[nodiscard]] int modifyRoute(unsigned netId, const char* interface, const char* destination,
166 const char* nexthop, RouteOperation op, bool legacy, uid_t uid,
167 int mtu);
168 [[nodiscard]] int modifyFallthroughLocked(unsigned vpnNetId, bool add);
169 void updateTcpSocketMonitorPolling();
170
171 class DelegateImpl;
172 DelegateImpl* const mDelegateImpl;
173
174 // mRWLock guards all accesses to mDefaultNetId, mNetworks, mUsers, mProtectableUsers,
175 // mIfindexToLastNetId and mAddressToIfindices.
176 mutable std::shared_mutex mRWLock;
177 unsigned mDefaultNetId;
178 std::map<unsigned, Network*> mNetworks; // Map keys are NetIds.
179 std::map<uid_t, Permission> mUsers;
180 std::set<uid_t> mProtectableUsers;
181 // Map interface (ifIndex) to its current NetId, or the last NetId if the interface was removed
182 // from the network and not added to another network. This state facilitates the interface to
183 // NetId lookup during RTM_DELADDR (NetworkController::removeInterfaceAddress), when the
184 // interface in question might already have been removed from the network.
185 // An interface is added to this map when it is added to a network and removed from this map
186 // when its network is destroyed.
187 std::unordered_map<unsigned, unsigned> mIfindexToLastNetId;
188 // Map IP address to the list of active interfaces (ifIndex) that have that address.
189 // Also contains IP addresses configured on interfaces that have not been added to any network.
190 // TODO: Does not track IP addresses present when netd is started or restarts after a crash.
191 // This is not a problem for its intended use (tracking IP addresses on VPN interfaces), but
192 // we should fix it.
193 std::unordered_map<std::string, std::unordered_set<unsigned>> mAddressToIfindices;
194
195 };
196
197 } // namespace android::net
198