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 "NetdConstants.h"
21 #include "Permission.h"
22 
23 #include "utils/RWLock.h"
24 
25 #include <list>
26 #include <map>
27 #include <set>
28 #include <sys/types.h>
29 #include <vector>
30 
31 class Network;
32 class UidRanges;
33 class VirtualNetwork;
34 
35 /*
36  * Keeps track of default, per-pid, and per-uid-range network selection, as
37  * well as the mark associated with each network. Networks are identified
38  * by netid. In all set* commands netid == 0 means "unspecified" and is
39  * equivalent to clearing the mapping.
40  */
41 class NetworkController {
42 public:
43     static const unsigned MIN_OEM_ID;
44     static const unsigned MAX_OEM_ID;
45     static const unsigned LOCAL_NET_ID;
46     static const unsigned DUMMY_NET_ID;
47 
48     NetworkController();
49 
50     unsigned getDefaultNetwork() const;
51     int setDefaultNetwork(unsigned netId) WARN_UNUSED_RESULT;
52 
53     // Sets |*netId| to an appropriate NetId to use for DNS for the given user. Call with |*netId|
54     // set to a non-NETID_UNSET value if the user already has indicated a preference. Returns the
55     // fwmark value to set on the socket when performing the DNS request.
56     uint32_t getNetworkForDns(unsigned* netId, uid_t uid) const;
57     unsigned getNetworkForUser(uid_t uid) const;
58     unsigned getNetworkForConnect(uid_t uid) const;
59     void getNetworkContext(unsigned netId, uid_t uid, struct android_net_context* netcontext) const;
60     unsigned getNetworkForInterface(const char* interface) const;
61     bool isVirtualNetwork(unsigned netId) const;
62 
63     int createPhysicalNetwork(unsigned netId, Permission permission) WARN_UNUSED_RESULT;
64     int createVirtualNetwork(unsigned netId, bool hasDns, bool secure) WARN_UNUSED_RESULT;
65     int destroyNetwork(unsigned netId) WARN_UNUSED_RESULT;
66 
67     int addInterfaceToNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
68     int removeInterfaceFromNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
69 
70     Permission getPermissionForUser(uid_t uid) const;
71     void setPermissionForUsers(Permission permission, const std::vector<uid_t>& uids);
72     int checkUserNetworkAccess(uid_t uid, unsigned netId) const;
73     int setPermissionForNetworks(Permission permission,
74                                  const std::vector<unsigned>& netIds) WARN_UNUSED_RESULT;
75 
76     int addUsersToNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
77     int removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
78 
79     // |nexthop| can be NULL (to indicate a directly-connected route), "unreachable" (to indicate a
80     // route that's blocked), "throw" (to indicate the lack of a match), or a regular IP address.
81     //
82     // Routes are added to tables determined by the interface, so only |interface| is actually used.
83     // |netId| is given only to sanity check that the interface has the correct netId.
84     int addRoute(unsigned netId, const char* interface, const char* destination,
85                  const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
86     int removeRoute(unsigned netId, const char* interface, const char* destination,
87                     const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
88 
89     bool canProtect(uid_t uid) const;
90     void allowProtect(const std::vector<uid_t>& uids);
91     void denyProtect(const std::vector<uid_t>& uids);
92 
93 private:
94     bool isValidNetwork(unsigned netId) const;
95     Network* getNetworkLocked(unsigned netId) const;
96     VirtualNetwork* getVirtualNetworkForUserLocked(uid_t uid) const;
97     Permission getPermissionForUserLocked(uid_t uid) const;
98     int checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const;
99 
100     int modifyRoute(unsigned netId, const char* interface, const char* destination,
101                     const char* nexthop, bool add, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
102     int modifyFallthroughLocked(unsigned vpnNetId, bool add) WARN_UNUSED_RESULT;
103 
104     class DelegateImpl;
105     DelegateImpl* const mDelegateImpl;
106 
107     // mRWLock guards all accesses to mDefaultNetId, mNetworks, mUsers and mProtectableUsers.
108     mutable android::RWLock mRWLock;
109     unsigned mDefaultNetId;
110     std::map<unsigned, Network*> mNetworks;  // Map keys are NetIds.
111     std::map<uid_t, Permission> mUsers;
112     std::set<uid_t> mProtectableUsers;
113 };
114 
115 #endif  // NETD_SERVER_NETWORK_CONTROLLER_H
116