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1 /*
2  *
3  * Copyright 2015 gRPC authors.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18 
19 #ifndef GRPC_CORE_LIB_IOMGR_TCP_SERVER_H
20 #define GRPC_CORE_LIB_IOMGR_TCP_SERVER_H
21 
22 #include <grpc/support/port_platform.h>
23 
24 #include <grpc/grpc.h>
25 #include <grpc/impl/codegen/grpc_types.h>
26 
27 #include <vector>
28 
29 #include "src/core/lib/iomgr/closure.h"
30 #include "src/core/lib/iomgr/endpoint.h"
31 #include "src/core/lib/iomgr/resolve_address.h"
32 
33 /* Forward decl of grpc_tcp_server */
34 typedef struct grpc_tcp_server grpc_tcp_server;
35 
36 typedef struct grpc_tcp_server_acceptor {
37   /* grpc_tcp_server_cb functions share a ref on from_server that is valid
38      until the function returns. */
39   grpc_tcp_server* from_server;
40   /* Indices that may be passed to grpc_tcp_server_port_fd(). */
41   unsigned port_index;
42   unsigned fd_index;
43   /* Data when the connection is passed to tcp_server from external. */
44   bool external_connection;
45   int listener_fd;
46   grpc_byte_buffer* pending_data;
47 } grpc_tcp_server_acceptor;
48 
49 /* Called for newly connected TCP connections.
50    Takes ownership of acceptor. */
51 typedef void (*grpc_tcp_server_cb)(void* arg, grpc_endpoint* ep,
52                                    grpc_pollset* accepting_pollset,
53                                    grpc_tcp_server_acceptor* acceptor);
54 namespace grpc_core {
55 // An interface for a handler to take a externally connected fd as a internal
56 // connection.
57 class TcpServerFdHandler {
58  public:
59   virtual ~TcpServerFdHandler() = default;
60   virtual void Handle(int listener_fd, int fd,
61                       grpc_byte_buffer* pending_read) = 0;
62 };
63 }  // namespace grpc_core
64 
65 typedef struct grpc_tcp_server_vtable {
66   grpc_error* (*create)(grpc_closure* shutdown_complete,
67                         const grpc_channel_args* args,
68                         grpc_tcp_server** server);
69   void (*start)(grpc_tcp_server* server,
70                 const std::vector<grpc_pollset*>* pollsets,
71                 grpc_tcp_server_cb on_accept_cb, void* cb_arg);
72   grpc_error* (*add_port)(grpc_tcp_server* s, const grpc_resolved_address* addr,
73                           int* out_port);
74   grpc_core::TcpServerFdHandler* (*create_fd_handler)(grpc_tcp_server* s);
75   unsigned (*port_fd_count)(grpc_tcp_server* s, unsigned port_index);
76   int (*port_fd)(grpc_tcp_server* s, unsigned port_index, unsigned fd_index);
77   grpc_tcp_server* (*ref)(grpc_tcp_server* s);
78   void (*shutdown_starting_add)(grpc_tcp_server* s,
79                                 grpc_closure* shutdown_starting);
80   void (*unref)(grpc_tcp_server* s);
81   void (*shutdown_listeners)(grpc_tcp_server* s);
82 } grpc_tcp_server_vtable;
83 
84 /* Create a server, initially not bound to any ports. The caller owns one ref.
85    If shutdown_complete is not NULL, it will be used by
86    grpc_tcp_server_unref() when the ref count reaches zero. */
87 grpc_error* grpc_tcp_server_create(grpc_closure* shutdown_complete,
88                                    const grpc_channel_args* args,
89                                    grpc_tcp_server** server);
90 
91 /* Start listening to bound ports */
92 void grpc_tcp_server_start(grpc_tcp_server* server,
93                            const std::vector<grpc_pollset*>* pollsets,
94                            grpc_tcp_server_cb on_accept_cb, void* cb_arg);
95 
96 /* Add a port to the server, returning the newly allocated port on success, or
97    -1 on failure.
98 
99    The :: and 0.0.0.0 wildcard addresses are treated identically, accepting
100    both IPv4 and IPv6 connections, but :: is the preferred style.  This usually
101    creates one socket, but possibly two on systems which support IPv6,
102    but not dualstack sockets. */
103 /* TODO(ctiller): deprecate this, and make grpc_tcp_server_add_ports to handle
104                   all of the multiple socket port matching logic in one place */
105 grpc_error* grpc_tcp_server_add_port(grpc_tcp_server* s,
106                                      const grpc_resolved_address* addr,
107                                      int* out_port);
108 
109 /* Create and return a TcpServerFdHandler so that it can be used by upper layer
110    to hand over an externally connected fd to the grpc server. */
111 grpc_core::TcpServerFdHandler* grpc_tcp_server_create_fd_handler(
112     grpc_tcp_server* s);
113 
114 /* Number of fds at the given port_index, or 0 if port_index is out of
115    bounds. */
116 unsigned grpc_tcp_server_port_fd_count(grpc_tcp_server* s, unsigned port_index);
117 
118 /* Returns the file descriptor of the Mth (fd_index) listening socket of the Nth
119    (port_index) call to add_port() on this server, or -1 if the indices are out
120    of bounds. The file descriptor remains owned by the server, and will be
121    cleaned up when the ref count reaches zero. */
122 int grpc_tcp_server_port_fd(grpc_tcp_server* s, unsigned port_index,
123                             unsigned fd_index);
124 
125 /* Ref s and return s. */
126 grpc_tcp_server* grpc_tcp_server_ref(grpc_tcp_server* s);
127 
128 /* shutdown_starting is called when ref count has reached zero and the server is
129    about to be destroyed. The server will be deleted after it returns. Calling
130    grpc_tcp_server_ref() from it has no effect. */
131 void grpc_tcp_server_shutdown_starting_add(grpc_tcp_server* s,
132                                            grpc_closure* shutdown_starting);
133 
134 /* If the refcount drops to zero, enqueue calls on exec_ctx to
135    shutdown_listeners and delete s. */
136 void grpc_tcp_server_unref(grpc_tcp_server* s);
137 
138 /* Shutdown the fds of listeners. */
139 void grpc_tcp_server_shutdown_listeners(grpc_tcp_server* s);
140 
141 void grpc_tcp_server_global_init();
142 
143 void grpc_set_tcp_server_impl(grpc_tcp_server_vtable* impl);
144 
145 #endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_H */
146