xref: /aosp_15_r20/frameworks/native/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp (revision 38e8c45f13ce32b0dcecb25141ffecaf386fa17f)
1 /*
2  * Copyright (C) 2021 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 <sys/socket.h>
20 #include <stdint.h>
21 
22 extern "C" {
23 
24 struct AIBinder;
25 struct ARpcServer;
26 struct ARpcSession;
27 
28 enum class ARpcSession_FileDescriptorTransportMode {
29     None,
30     Unix,
31     Trusty,
32 };
33 
34 // Starts an RPC server on a given port and a given root IBinder object.
35 // The server will only accept connections from the given CID.
36 // Set `cid` to VMADDR_CID_ANY to accept connections from any client.
37 // Set `cid` to VMADDR_CID_LOCAL to only bind to the local vsock interface.
38 // Returns an opaque handle to the running server instance, or null if the server
39 // could not be started.
40 // Set |port| to VMADDR_PORT_ANY to pick an available ephemeral port.
41 // |assignedPort| will be set to the assigned port number if it is not null.
42 // This will be the provided |port|, or the chosen available ephemeral port when
43 // |port| is VMADDR_PORT_ANY.
44 [[nodiscard]] ARpcServer* ARpcServer_newVsock(AIBinder* service, unsigned int cid,
45                                               unsigned int port, unsigned int* assignedPort);
46 
47 // Starts a Unix domain RPC server with an open raw socket file descriptor
48 // and a given root IBinder object.
49 // The socket should be created and bound to an address.
50 // Returns an opaque handle to the running server instance, or null if the server
51 // could not be started.
52 // The socket will be closed by the server once the server goes out of scope.
53 [[nodiscard]] ARpcServer* ARpcServer_newBoundSocket(AIBinder* service, int socketFd);
54 
55 // Starts an RPC server that bootstraps sessions using an existing Unix domain
56 // socket pair, with a given root IBinder object.
57 // Callers should create a pair of SOCK_STREAM Unix domain sockets, pass one to
58 // this function and the other to UnixDomainBootstrapClient(). Multiple client
59 // session can be created from the client end of the pair.
60 // Does not take ownership of `service`.
61 // Returns an opaque handle to the running server instance, or null if the server
62 // could not be started.
63 [[nodiscard]] ARpcServer* ARpcServer_newUnixDomainBootstrap(AIBinder* service, int bootstrapFd);
64 
65 // Starts an RPC server on a given IP address+port and a given IBinder object.
66 // Returns an opaque handle to the running server instance, or null if the server
67 // could not be started.
68 // Does not take ownership of `service`.
69 // Returns an opaque handle to the running service instance, or null if the server
70 // could not be started.
71 [[nodiscard]] ARpcServer* ARpcServer_newInet(AIBinder* service, const char* address,
72                                              unsigned int port);
73 
74 // Sets the list of supported file descriptor transport modes of this RPC server.
75 void ARpcServer_setSupportedFileDescriptorTransportModes(
76         ARpcServer* handle,
77         const ARpcSession_FileDescriptorTransportMode modes[],
78         size_t modes_len);
79 
80 // Sets the maximum number of threads that the Server will use for
81 // incoming client connections.
82 //
83 // This must be called before adding a client session. This corresponds
84 // to the number of incoming connections to RpcSession objects in the
85 // server, which will correspond to the number of outgoing connections
86 // in client RpcSession objects.
87 //
88 // If this is not specified, this will be a single-threaded server.
89 void ARpcServer_setMaxThreads(ARpcServer* server, size_t threads);
90 
91 // Runs ARpcServer_join() in a background thread. Immediately returns.
92 void ARpcServer_start(ARpcServer* server);
93 
94 // Joins the thread of a running RpcServer instance. At any given point, there
95 // can only be one thread calling ARpcServer_join().
96 // If a client needs to actively terminate join, call ARpcServer_shutdown() in
97 // a separate thread.
98 void ARpcServer_join(ARpcServer* server);
99 
100 // Shuts down any running ARpcServer_join().
101 [[nodiscard]] bool ARpcServer_shutdown(ARpcServer* server);
102 
103 // Frees the ARpcServer handle and drops the reference count on the underlying
104 // RpcServer instance. The handle must not be reused afterwards.
105 // This automatically calls ARpcServer_shutdown().
106 void ARpcServer_free(ARpcServer* server);
107 
108 // Allocates a new RpcSession object and returns an opaque handle to it.
109 [[nodiscard]] ARpcSession* ARpcSession_new();
110 
111 // Connects to an RPC server over vsock at a given CID on a given port.
112 // Returns the root Binder object of the server.
113 AIBinder* ARpcSession_setupVsockClient(ARpcSession* session, unsigned int cid,
114                                        unsigned int port);
115 
116 // Connects to an RPC server over a Unix Domain Socket of the given name.
117 // The final Unix Domain Socket path name is /dev/socket/`name`.
118 // Returns the root Binder object of the server.
119 AIBinder* ARpcSession_setupUnixDomainClient(ARpcSession* session, const char* name);
120 
121 // Connects to an RPC server over the given bootstrap Unix domain socket.
122 // Does NOT take ownership of `bootstrapFd`.
123 AIBinder* ARpcSession_setupUnixDomainBootstrapClient(ARpcSession* session,
124                                                      int bootstrapFd);
125 
126 // Connects to an RPC server over an INET socket at a given IP address on a given port.
127 // Returns the root Binder object of the server.
128 AIBinder* ARpcSession_setupInet(ARpcSession* session, const char* address, unsigned int port);
129 
130 // Connects to an RPC server with preconnected file descriptors.
131 //
132 // requestFd should connect to the server and return a valid file descriptor, or
133 // -1 if connection fails.
134 //
135 // param will be passed to requestFd. Callers can use param to pass contexts to
136 // the requestFd function.
137 AIBinder* ARpcSession_setupPreconnectedClient(ARpcSession* session,
138                                               int (*requestFd)(void* param),
139                                               void* param);
140 
141 // Sets the file descriptor transport mode for this session.
142 void ARpcSession_setFileDescriptorTransportMode(ARpcSession* session,
143                                                 ARpcSession_FileDescriptorTransportMode mode);
144 
145 // Sets the maximum number of incoming threads, to service connections.
146 void ARpcSession_setMaxIncomingThreads(ARpcSession* session, size_t threads);
147 
148 // Sets the maximum number of outgoing connections.
149 void ARpcSession_setMaxOutgoingConnections(ARpcSession* session, size_t connections);
150 
151 // Decrements the refcount of the underlying RpcSession object.
152 void ARpcSession_free(ARpcSession* session);
153 }
154