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 "src/core/lib/iomgr/closure.h"
28 #include "src/core/lib/iomgr/endpoint.h"
29 #include "src/core/lib/iomgr/resolve_address.h"
30 
31 /* Forward decl of grpc_tcp_server */
32 typedef struct grpc_tcp_server grpc_tcp_server;
33 
34 typedef struct grpc_tcp_server_acceptor {
35   /* grpc_tcp_server_cb functions share a ref on from_server that is valid
36      until the function returns. */
37   grpc_tcp_server* from_server;
38   /* Indices that may be passed to grpc_tcp_server_port_fd(). */
39   unsigned port_index;
40   unsigned fd_index;
41   /* Data when the connection is passed to tcp_server from external. */
42   bool external_connection;
43   int listener_fd;
44   grpc_byte_buffer* pending_data;
45 } grpc_tcp_server_acceptor;
46 
47 /* Called for newly connected TCP connections.
48    Takes ownership of acceptor. */
49 typedef void (*grpc_tcp_server_cb)(void* arg, grpc_endpoint* ep,
50                                    grpc_pollset* accepting_pollset,
51                                    grpc_tcp_server_acceptor* acceptor);
52 namespace grpc_core {
53 // An interface for a handler to take a externally connected fd as a internal
54 // connection.
55 class TcpServerFdHandler {
56  public:
57   virtual ~TcpServerFdHandler() = default;
58   virtual void Handle(int listener_fd, int fd,
59                       grpc_byte_buffer* pending_read) = 0;
60 };
61 }  // namespace grpc_core
62 
63 typedef struct grpc_tcp_server_vtable {
64   grpc_error* (*create)(grpc_closure* shutdown_complete,
65                         const grpc_channel_args* args,
66                         grpc_tcp_server** server);
67   void (*start)(grpc_tcp_server* server, grpc_pollset** pollsets,
68                 size_t pollset_count, grpc_tcp_server_cb on_accept_cb,
69                 void* cb_arg);
70   grpc_error* (*add_port)(grpc_tcp_server* s, const grpc_resolved_address* addr,
71                           int* out_port);
72   grpc_core::TcpServerFdHandler* (*create_fd_handler)(grpc_tcp_server* s);
73   unsigned (*port_fd_count)(grpc_tcp_server* s, unsigned port_index);
74   int (*port_fd)(grpc_tcp_server* s, unsigned port_index, unsigned fd_index);
75   grpc_tcp_server* (*ref)(grpc_tcp_server* s);
76   void (*shutdown_starting_add)(grpc_tcp_server* s,
77                                 grpc_closure* shutdown_starting);
78   void (*unref)(grpc_tcp_server* s);
79   void (*shutdown_listeners)(grpc_tcp_server* s);
80 } grpc_tcp_server_vtable;
81 
82 /* Create a server, initially not bound to any ports. The caller owns one ref.
83    If shutdown_complete is not NULL, it will be used by
84    grpc_tcp_server_unref() when the ref count reaches zero. */
85 grpc_error* grpc_tcp_server_create(grpc_closure* shutdown_complete,
86                                    const grpc_channel_args* args,
87                                    grpc_tcp_server** server);
88 
89 /* Start listening to bound ports */
90 void grpc_tcp_server_start(grpc_tcp_server* server, grpc_pollset** pollsets,
91                            size_t pollset_count,
92                            grpc_tcp_server_cb on_accept_cb, void* cb_arg);
93 
94 /* Add a port to the server, returning the newly allocated port on success, or
95    -1 on failure.
96 
97    The :: and 0.0.0.0 wildcard addresses are treated identically, accepting
98    both IPv4 and IPv6 connections, but :: is the preferred style.  This usually
99    creates one socket, but possibly two on systems which support IPv6,
100    but not dualstack sockets. */
101 /* TODO(ctiller): deprecate this, and make grpc_tcp_server_add_ports to handle
102                   all of the multiple socket port matching logic in one place */
103 grpc_error* grpc_tcp_server_add_port(grpc_tcp_server* s,
104                                      const grpc_resolved_address* addr,
105                                      int* out_port);
106 
107 /* Create and return a TcpServerFdHandler so that it can be used by upper layer
108    to hand over an externally connected fd to the grpc server. */
109 grpc_core::TcpServerFdHandler* grpc_tcp_server_create_fd_handler(
110     grpc_tcp_server* s);
111 
112 /* Number of fds at the given port_index, or 0 if port_index is out of
113    bounds. */
114 unsigned grpc_tcp_server_port_fd_count(grpc_tcp_server* s, unsigned port_index);
115 
116 /* Returns the file descriptor of the Mth (fd_index) listening socket of the Nth
117    (port_index) call to add_port() on this server, or -1 if the indices are out
118    of bounds. The file descriptor remains owned by the server, and will be
119    cleaned up when the ref count reaches zero. */
120 int grpc_tcp_server_port_fd(grpc_tcp_server* s, unsigned port_index,
121                             unsigned fd_index);
122 
123 /* Ref s and return s. */
124 grpc_tcp_server* grpc_tcp_server_ref(grpc_tcp_server* s);
125 
126 /* shutdown_starting is called when ref count has reached zero and the server is
127    about to be destroyed. The server will be deleted after it returns. Calling
128    grpc_tcp_server_ref() from it has no effect. */
129 void grpc_tcp_server_shutdown_starting_add(grpc_tcp_server* s,
130                                            grpc_closure* shutdown_starting);
131 
132 /* If the refcount drops to zero, enqueue calls on exec_ctx to
133    shutdown_listeners and delete s. */
134 void grpc_tcp_server_unref(grpc_tcp_server* s);
135 
136 /* Shutdown the fds of listeners. */
137 void grpc_tcp_server_shutdown_listeners(grpc_tcp_server* s);
138 
139 void grpc_tcp_server_global_init();
140 
141 void grpc_set_tcp_server_impl(grpc_tcp_server_vtable* impl);
142 
143 #endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_H */
144