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1 /*
2  * nghttp2 - HTTP/2 C Library
3  *
4  * Copyright (c) 2016 Tatsuhiro Tsujikawa
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining
7  * a copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sublicense, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be
15  * included in all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
22  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
23  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24  */
25 #ifndef SHRPX_LIVE_CHECK_H
26 #define SHRPX_LIVE_CHECK_H
27 
28 #include "shrpx.h"
29 
30 #include <functional>
31 #include <random>
32 
33 #include <openssl/ssl.h>
34 
35 #include <ev.h>
36 
37 #include <nghttp2/nghttp2.h>
38 
39 #include "shrpx_connection.h"
40 
41 namespace shrpx {
42 
43 class Worker;
44 struct DownstreamAddr;
45 struct DNSQuery;
46 
47 class LiveCheck {
48 public:
49   LiveCheck(struct ev_loop *loop, SSL_CTX *ssl_ctx, Worker *worker,
50             DownstreamAddr *addr, std::mt19937 &gen);
51   ~LiveCheck();
52 
53   void disconnect();
54 
55   void on_success();
56   void on_failure();
57 
58   int initiate_connection();
59 
60   // Schedules next connection attempt
61   void schedule();
62 
63   // Low level I/O operation callback; they are called from do_read()
64   // or do_write().
65   int noop();
66   int connected();
67   int tls_handshake();
68   int read_tls();
69   int write_tls();
70   int read_clear();
71   int write_clear();
72 
73   int do_read();
74   int do_write();
75 
76   // These functions are used to feed / extract data to
77   // nghttp2_session object.
78   int on_read(const uint8_t *data, size_t len);
79   int on_write();
80 
81   // Call this function when HTTP/2 connection was established.  We
82   // don't call this function for HTTP/1 at the moment.
83   int connection_made();
84 
85   void start_settings_timer();
86   void stop_settings_timer();
87 
88   // Call this function when SETTINGS ACK was received from server.
89   void settings_ack_received();
90 
91   void signal_write();
92 
93 private:
94   Connection conn_;
95   DefaultMemchunks wb_;
96   std::mt19937 &gen_;
97   ev_timer backoff_timer_;
98   ev_timer settings_timer_;
99   std::function<int(LiveCheck &)> read_, write_;
100   Worker *worker_;
101   // nullptr if no TLS is configured
102   SSL_CTX *ssl_ctx_;
103   // Address of remote endpoint
104   DownstreamAddr *addr_;
105   nghttp2_session *session_;
106   // Actual remote address used to contact backend.  This is initially
107   // nullptr, and may point to either &addr_->addr, or
108   // resolved_addr_.get().
109   const Address *raddr_;
110   // Resolved IP address if dns parameter is used
111   std::unique_ptr<Address> resolved_addr_;
112   std::unique_ptr<DNSQuery> dns_query_;
113   // The number of successful connect attempt in a row.
114   size_t success_count_;
115   // The number of unsuccessful connect attempt in a row.
116   size_t fail_count_;
117   // true when SETTINGS ACK has been received from server.
118   bool settings_ack_received_;
119   // true when GOAWAY has been queued.
120   bool session_closing_;
121 };
122 
123 } // namespace shrpx
124 
125 #endif // SHRPX_LIVE_CHECK_H
126