1 /*
2  * Copyright (C) 2015 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 /**
18  * @addtogroup Networking
19  * @{
20  */
21 
22 /**
23  * @file multinetwork.h
24  */
25 
26 #ifndef ANDROID_MULTINETWORK_H
27 #define ANDROID_MULTINETWORK_H
28 
29 #include <netdb.h>
30 #include <stdlib.h>
31 #include <sys/cdefs.h>
32 
33 __BEGIN_DECLS
34 
35 /**
36  * The corresponding C type for android.net.Network#getNetworkHandle() return
37  * values.  The Java signed long value can be safely cast to a net_handle_t:
38  *
39  *     [C]    ((net_handle_t) java_long_network_handle)
40  *     [C++]  static_cast<net_handle_t>(java_long_network_handle)
41  *
42  * as appropriate.
43  */
44 typedef uint64_t net_handle_t;
45 
46 /**
47  * The value NETWORK_UNSPECIFIED indicates no specific network.
48  *
49  * For some functions (documented below), a previous binding may be cleared
50  * by an invocation with NETWORK_UNSPECIFIED.
51  *
52  * Depending on the context it may indicate an error.  It is expressly
53  * not used to indicate some notion of the "current default network".
54  */
55 #define NETWORK_UNSPECIFIED  ((net_handle_t)0)
56 
57 
58 /**
59  * All functions below that return an int return 0 on success or -1
60  * on failure with an appropriate errno value set.
61  */
62 
63 /**
64  * Set the network to be used by the given socket file descriptor.
65  *
66  * To clear a previous socket binding, invoke with NETWORK_UNSPECIFIED.
67  *
68  * This is the equivalent of: [android.net.Network#bindSocket()](https://developer.android.com/reference/android/net/Network.html#bindSocket(java.net.Socket))
69  *
70  * Available since API level 23.
71  */
72 int android_setsocknetwork(net_handle_t network, int fd) __INTRODUCED_IN(23);
73 
74 
75 /**
76  * Binds the current process to |network|.  All sockets created in the future
77  * (and not explicitly bound via android_setsocknetwork()) will be bound to
78  * |network|.  All host name resolutions will be limited to |network| as well.
79  * Note that if the network identified by |network| ever disconnects, all
80  * sockets created in this way will cease to work and all host name
81  * resolutions will fail.  This is by design so an application doesn't
82  * accidentally use sockets it thinks are still bound to a particular network.
83  *
84  * To clear a previous process binding, invoke with NETWORK_UNSPECIFIED.
85  *
86  * This is the equivalent of: [android.net.ConnectivityManager#bindProcessToNetwork()](https://developer.android.com/reference/android/net/ConnectivityManager.html#bindProcessToNetwork(android.net.Network))
87  *
88  * Available since API level 23.
89  */
90 int android_setprocnetwork(net_handle_t network) __INTRODUCED_IN(23);
91 
92 
93 /**
94  * Gets the |network| bound to the current process, as per android_setprocnetwork.
95  *
96  * This is the equivalent of: [android.net.ConnectivityManager#getBoundNetworkForProcess()](https://developer.android.com/reference/android/net/ConnectivityManager.html#getBoundNetworkForProcess(android.net.Network))
97  * Returns 0 on success, or -1 setting errno to EINVAL if a null pointer is
98  * passed in.
99  *
100  *
101  * Available since API level 31.
102  */
103 int android_getprocnetwork(net_handle_t *network) __INTRODUCED_IN(31);
104 
105 /**
106  * Binds domain name resolutions performed by this process to |network|.
107  * android_setprocnetwork takes precedence over this setting.
108  *
109  * To clear a previous process binding, invoke with NETWORK_UNSPECIFIED.
110  * On success 0 is returned. On error -1 is returned, and errno is set.
111  *
112  * Available since API level 31.
113  */
114 int android_setprocdns(net_handle_t network) __INTRODUCED_IN(31);
115 
116 /**
117  * Gets the |network| to which domain name resolutions are bound on the
118  * current process.
119  *
120  * Returns 0 on success, or -1 setting errno to EINVAL if a null pointer is
121  * passed in.
122  *
123  * Available since API level 31.
124  */
125 int android_getprocdns(net_handle_t *network) __INTRODUCED_IN(31);
126 
127 
128 /**
129  * Perform hostname resolution via the DNS servers associated with |network|.
130  *
131  * All arguments (apart from |network|) are used identically as those passed
132  * to getaddrinfo(3).  Return and error values are identical to those of
133  * getaddrinfo(3), and in particular gai_strerror(3) can be used as expected.
134  * Similar to getaddrinfo(3):
135  *     - |hints| may be NULL (in which case man page documented defaults apply)
136  *     - either |node| or |service| may be NULL, but not both
137  *     - |res| must not be NULL
138  *
139  * This is the equivalent of: [android.net.Network#getAllByName()](https://developer.android.com/reference/android/net/Network.html#getAllByName(java.lang.String))
140  *
141  * Available since API level 23.
142  */
143 int android_getaddrinfofornetwork(net_handle_t network,
144         const char *node, const char *service,
145         const struct addrinfo *hints, struct addrinfo **res) __INTRODUCED_IN(23);
146 
147 /**
148  * Possible values of the flags argument to android_res_nsend and android_res_nquery.
149  * Values are ORed together.
150  */
151 enum ResNsendFlags : uint32_t {
152     /**
153      * Send a single request to a single resolver and fail on timeout or network errors
154      */
155     ANDROID_RESOLV_NO_RETRY = 1 << 0,
156 
157     /**
158      * Don't lookup this request in the cache, and don't cache the result of the lookup.
159      * This flag implies {@link #ANDROID_RESOLV_NO_CACHE_LOOKUP}.
160      */
161     ANDROID_RESOLV_NO_CACHE_STORE = 1 << 1,
162 
163     /**
164      * Don't lookup the request in cache.
165      */
166     ANDROID_RESOLV_NO_CACHE_LOOKUP = 1 << 2,
167 };
168 
169 /**
170  * Look up the {|ns_class|, |ns_type|} Resource Record (RR) associated
171  * with Domain Name |dname| on the given |network|.
172  * The typical value for |ns_class| is ns_c_in, while |type| can be any
173  * record type (for instance, ns_t_aaaa or ns_t_txt).
174  * |flags| is a additional config to control actual querying behavior, see
175  * ResNsendFlags for detail.
176  *
177  * Returns a file descriptor to watch for read events, or a negative
178  * POSIX error code (see errno.h) if an immediate error occurs.
179  *
180  * Available since API level 29.
181  */
182 int android_res_nquery(net_handle_t network,
183         const char *dname, int ns_class, int ns_type, uint32_t flags) __INTRODUCED_IN(29);
184 
185 /**
186  * Issue the query |msg| on the given |network|.
187  * |flags| is a additional config to control actual querying behavior, see
188  * ResNsendFlags for detail.
189  *
190  * Returns a file descriptor to watch for read events, or a negative
191  * POSIX error code (see errno.h) if an immediate error occurs.
192  *
193  * Available since API level 29.
194  */
195 int android_res_nsend(net_handle_t network,
196         const uint8_t *msg, size_t msglen, uint32_t flags) __INTRODUCED_IN(29);
197 
198 /**
199  * Read a result for the query associated with the |fd| descriptor.
200  * Closes |fd| before returning.
201  *
202  * Available since 29.
203  *
204  * Returns:
205  *     < 0: negative POSIX error code (see errno.h for possible values). |rcode| is not set.
206  *     >= 0: length of |answer|. |rcode| is the resolver return code (e.g., ns_r_nxdomain)
207  */
208 int android_res_nresult(int fd,
209         int *rcode, uint8_t *answer, size_t anslen) __INTRODUCED_IN(29);
210 
211 /**
212  * Attempts to cancel the in-progress query associated with the |nsend_fd|
213  * descriptor.
214  *
215  * Available since API level 29.
216  */
217 void android_res_cancel(int nsend_fd) __INTRODUCED_IN(29);
218 
219 /*
220  * Set the socket tag and owning UID for traffic statistics on the specified
221  * socket.
222  *
223  * Subsequent calls always replace any existing parameters. The socket tag and
224  * uid (if set) are kept when the socket is sent to another process using binder
225  * IPCs or other mechanisms such as UNIX socket fd passing. Any app can accept
226  * blame for future traffic performed on a socket originally created by another
227  * app by calling this method with its own UID (or calling
228  * android_tag_socket(int sockfd, int tag)). However, only apps holding the
229  * android.Manifest.permission#UPDATE_DEVICE_STATS permission may assign blame
230  * to another UIDs. If unset (default) the socket tag is 0, and the uid is the
231  * socket creator's uid.
232  *
233  * Returns 0 on success, or a negative POSIX error code (see errno.h) on
234  * failure.
235  *
236  * Available since API level 33.
237  */
238 int android_tag_socket_with_uid(int sockfd, uint32_t tag, uid_t uid) __INTRODUCED_IN(33);
239 
240 /*
241  * Set the socket tag for traffic statistics on the specified socket.
242  *
243  * This function tags the socket with the caller's UID (accepting blame for
244  * future traffic performed on this socket) even if the socket was originally
245  * opened by another UID or was previously tagged by another UID. Subsequent
246  * calls always replace any existing parameters. The socket tag is kept when the
247  * socket is sent to another process using binder IPCs or other mechanisms such
248  * as UNIX socket fd passing. The tag is a value defined by the caller and used
249  * together with uid for data traffic accounting, so that the function callers
250  * can account different types of data usage for a uid.
251  *
252  * Returns 0 on success, or a negative POSIX error code (see errno.h) on
253  * failure.
254  *
255  * Some possible error codes:
256  * -EBADF           Bad socketfd.
257  * -EPERM           No permission.
258  * -EAFNOSUPPORT    Socket family is neither AF_INET nor AF_INET6.
259  * -EPROTONOSUPPORT Socket protocol is neither IPPROTO_UDP nor IPPROTO_TCP.
260  * -EMFILE          Too many stats entries.
261  * There are still other error codes that may provided by -errno of
262  * [getsockopt()](https://man7.org/linux/man-pages/man2/getsockopt.2.html) or by
263  * BPF maps read/write sys calls, which are set appropriately.
264  *
265  * Available since API level 33.
266  */
267 int android_tag_socket(int sockfd, uint32_t tag) __INTRODUCED_IN(33);
268 
269 /*
270  * Untag a network socket.
271  *
272  * Future traffic on this socket will no longer be associated with any
273  * previously configured tag and uid. If the socket was created by another UID
274  * or was previously tagged by another UID, calling this function will clear the
275  * statistics parameters, and thus the UID blamed for traffic on the socket will
276  * be the UID that originally created the socket, even if the socket was
277  * subsequently tagged by a different UID.
278  *
279  * Returns 0 on success, or a negative POSIX error code (see errno.h) on
280  * failure.
281  *
282  * One of possible error code:
283  * -EBADF           Bad socketfd.
284  * Other error codes are either provided by -errno of
285  * [getsockopt()](https://man7.org/linux/man-pages/man2/getsockopt.2.html) or by
286  * BPF map element deletion sys call, which are set appropriately.
287  *
288  * Available since API level 33.
289  */
290 int android_untag_socket(int sockfd) __INTRODUCED_IN(33);
291 
292 __END_DECLS
293 
294 #endif  // ANDROID_MULTINETWORK_H
295 
296 /** @} */
297