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/multinetwork.h>
21#include "NetdConstants.h"
22#include "Permission.h"
23
24#include "utils/RWLock.h"
25
26#include <list>
27#include <map>
28#include <set>
29#include <sys/types.h>
30#include <vector>
31
32struct android_net_context;
33
34namespace android {
35namespace net {
36
37// Utility to convert from netId to net_handle_t. Doing this here as opposed to exporting
38// from net.c as it may have NDK implications. Besides no conversion available in net.c for
39// obtaining handle given netId.
40// TODO: Use getnetidfromhandle() in net.c.
41static inline unsigned netHandleToNetId(net_handle_t fromNetHandle) {
42    const uint32_t k32BitMask = 0xffffffff;
43    // This value MUST be kept in sync with the corresponding value in
44    // the android.net.Network#getNetworkHandle() implementation.
45    const uint32_t kHandleMagic = 0xfacade;
46
47    // Check for minimum acceptable version of the API in the low bits.
48    if (fromNetHandle != NETWORK_UNSPECIFIED &&
49        (fromNetHandle & k32BitMask) != kHandleMagic) {
50        return 0;
51    }
52
53    return ((fromNetHandle >> (CHAR_BIT * sizeof(k32BitMask))) & k32BitMask);
54}
55
56// Utility to convert from nethandle to netid, keep in sync with getNetworkHandle
57// in Network.java.
58static inline net_handle_t netIdToNetHandle(unsigned fromNetId) {
59    const net_handle_t HANDLE_MAGIC = 0xfacade;
60
61    if (!fromNetId) {
62        return NETWORK_UNSPECIFIED;
63    }
64    return (((net_handle_t)fromNetId << 32) | HANDLE_MAGIC);
65}
66
67class DumpWriter;
68class Network;
69class UidRanges;
70class VirtualNetwork;
71
72/*
73 * Keeps track of default, per-pid, and per-uid-range network selection, as
74 * well as the mark associated with each network. Networks are identified
75 * by netid. In all set* commands netid == 0 means "unspecified" and is
76 * equivalent to clearing the mapping.
77 */
78class NetworkController {
79public:
80    static const unsigned MIN_OEM_ID;
81    static const unsigned MAX_OEM_ID;
82    static const unsigned LOCAL_NET_ID;
83    static const unsigned DUMMY_NET_ID;
84
85    NetworkController();
86
87    unsigned getDefaultNetwork() const;
88    int setDefaultNetwork(unsigned netId) WARN_UNUSED_RESULT;
89
90    // Sets |*netId| to an appropriate NetId to use for DNS for the given user. Call with |*netId|
91    // set to a non-NETID_UNSET value if the user already has indicated a preference. Returns the
92    // fwmark value to set on the socket when performing the DNS request.
93    uint32_t getNetworkForDns(unsigned* netId, uid_t uid) const;
94    unsigned getNetworkForUser(uid_t uid) const;
95    unsigned getNetworkForConnect(uid_t uid) const;
96    void getNetworkContext(unsigned netId, uid_t uid, struct android_net_context* netcontext) const;
97    unsigned getNetworkForInterface(const char* interface) const;
98    bool isVirtualNetwork(unsigned netId) const;
99
100    int createPhysicalNetwork(unsigned netId, Permission permission) WARN_UNUSED_RESULT;
101    int createPhysicalOemNetwork(Permission permission, unsigned *netId) WARN_UNUSED_RESULT;
102    int createVirtualNetwork(unsigned netId, bool hasDns, bool secure) WARN_UNUSED_RESULT;
103    int destroyNetwork(unsigned netId) WARN_UNUSED_RESULT;
104
105    int addInterfaceToNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
106    int removeInterfaceFromNetwork(unsigned netId, const char* interface) WARN_UNUSED_RESULT;
107
108    Permission getPermissionForUser(uid_t uid) const;
109    void setPermissionForUsers(Permission permission, const std::vector<uid_t>& uids);
110    int checkUserNetworkAccess(uid_t uid, unsigned netId) const;
111    int setPermissionForNetworks(Permission permission,
112                                 const std::vector<unsigned>& netIds) WARN_UNUSED_RESULT;
113
114    int addUsersToNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
115    int removeUsersFromNetwork(unsigned netId, const UidRanges& uidRanges) WARN_UNUSED_RESULT;
116
117    // |nexthop| can be NULL (to indicate a directly-connected route), "unreachable" (to indicate a
118    // route that's blocked), "throw" (to indicate the lack of a match), or a regular IP address.
119    //
120    // Routes are added to tables determined by the interface, so only |interface| is actually used.
121    // |netId| is given only to sanity check that the interface has the correct netId.
122    int addRoute(unsigned netId, const char* interface, const char* destination,
123                 const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
124    int removeRoute(unsigned netId, const char* interface, const char* destination,
125                    const char* nexthop, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
126
127    bool canProtect(uid_t uid) const;
128    void allowProtect(const std::vector<uid_t>& uids);
129    void denyProtect(const std::vector<uid_t>& uids);
130
131    void dump(DumpWriter& dw);
132
133private:
134    bool isValidNetwork(unsigned netId) const;
135    bool isValidNetworkLocked(unsigned netId) const;
136    Network* getNetworkLocked(unsigned netId) const;
137    VirtualNetwork* getVirtualNetworkForUserLocked(uid_t uid) const;
138    Permission getPermissionForUserLocked(uid_t uid) const;
139    int checkUserNetworkAccessLocked(uid_t uid, unsigned netId) const;
140    int createPhysicalNetworkLocked(unsigned netId, Permission permission) WARN_UNUSED_RESULT;
141
142    int modifyRoute(unsigned netId, const char* interface, const char* destination,
143                    const char* nexthop, bool add, bool legacy, uid_t uid) WARN_UNUSED_RESULT;
144    int modifyFallthroughLocked(unsigned vpnNetId, bool add) WARN_UNUSED_RESULT;
145
146    class DelegateImpl;
147    DelegateImpl* const mDelegateImpl;
148
149    // mRWLock guards all accesses to mDefaultNetId, mNetworks, mUsers and mProtectableUsers.
150    mutable android::RWLock mRWLock;
151    unsigned mDefaultNetId;
152    std::map<unsigned, Network*> mNetworks;  // Map keys are NetIds.
153    std::map<uid_t, Permission> mUsers;
154    std::set<uid_t> mProtectableUsers;
155};
156
157}  // namespace net
158}  // namespace android
159
160#endif  // NETD_SERVER_NETWORK_CONTROLLER_H
161