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1 : : // Copyright (c) 2015-present The Bitcoin Core developers
2 : : // Distributed under the MIT software license, see the accompanying
3 : : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 : :
5 : : #ifndef BITCOIN_HTTPSERVER_H
6 : : #define BITCOIN_HTTPSERVER_H
7 : :
8 : : #include <atomic>
9 : : #include <functional>
10 : : #include <memory>
11 : : #include <optional>
12 : : #include <span>
13 : : #include <stdexcept>
14 : : #include <string>
15 : : #include <vector>
16 : :
17 : : #include <netaddress.h>
18 : : #include <rpc/protocol.h>
19 : : #include <util/byte_units.h>
20 : : #include <util/expected.h>
21 : : #include <util/sock.h>
22 : : #include <util/strencodings.h>
23 : : #include <util/string.h>
24 : : #include <util/threadinterrupt.h>
25 : : #include <util/time.h>
26 : :
27 : : namespace util {
28 : : class SignalInterrupt;
29 : : } // namespace util
30 : :
31 : : /**
32 : : * The default value for `-rpcthreads`. This number of threads will be created at startup.
33 : : */
34 : : inline constexpr int DEFAULT_HTTP_THREADS=16;
35 : :
36 : : /**
37 : : * The default value for `-rpcworkqueue`. This is the maximum depth of the work queue,
38 : : * we don't allocate this number of work queue items upfront.
39 : : */
40 : : inline constexpr int DEFAULT_HTTP_WORKQUEUE=64;
41 : :
42 : : inline constexpr int DEFAULT_HTTP_SERVER_TIMEOUT=30;
43 : :
44 : : /**
45 : : * Maximum number of connected HTTP clients
46 : : */
47 : : inline constexpr int DEFAULT_MAX_HTTP_CONNECTIONS = 16;
48 : :
49 : : enum class HTTPRequestMethod {
50 : : UNKNOWN,
51 : : GET,
52 : : POST,
53 : : HEAD,
54 : : PUT
55 : : };
56 : :
57 : : class HTTPRequest;
58 : :
59 : : /** Handler for requests to a certain HTTP path */
60 : : using HTTPRequestHandler = std::function<void(HTTPRequest* req, const std::string&)>;
61 : :
62 : : /** Register handler for prefix.
63 : : * If multiple handlers match a prefix, the first-registered one will
64 : : * be invoked.
65 : : */
66 : : void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler);
67 : : /** Unregister handler for prefix */
68 : : void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch);
69 : :
70 : : namespace bitcoin_http {
71 : : //! Shortest valid request line, used by libevent in evhttp_parse_request_line()
72 : : inline constexpr size_t MIN_REQUEST_LINE_LENGTH = std::string_view("GET / HTTP/1.0").size();
73 : :
74 : : //! Maximum size of each headers line in an HTTP request,
75 : : //! also the maximum size of all headers total.
76 : : //! See https://github.com/bitcoin/bitcoin/pull/6859
77 : : //! And libevent http.c evhttp_parse_headers_()
78 : : inline constexpr size_t MAX_HEADERS_SIZE{8192};
79 : :
80 : : //! Maximum size of an HTTP request body
81 : : inline constexpr uint64_t MAX_BODY_SIZE{32_MiB};
82 : :
83 : : //! Thrown when a request body exceeds MAX_BODY_SIZE (or *will* exceed, in chunked transfer)
84 : : //! so the server can reply with more specific code 413 (content too large) vs general 400 (bad request)
85 : : struct ContentTooLargeError : std::runtime_error {
86 [ # # # # ]: 0 : using std::runtime_error::runtime_error;
87 : : };
88 : : } // namespace bitcoin_http
89 : :
90 [ # # ]: 312 : class HTTPHeaders
91 : : {
92 : : public:
93 : : /**
94 : : * @param[in] key The field-name of the header to search for
95 : : * @returns The value of the first header that matches the provided key
96 : : * nullopt if key is not found
97 : : */
98 : : std::optional<std::string> FindFirst(std::string_view key) const;
99 : : /**
100 : : * @param[in] key The field-name of the header to search for
101 : : * @returns Views into all values matching the provided key (valid while this object is alive)
102 : : */
103 : : std::vector<std::string_view> FindAll(std::string_view key) const;
104 : : void Write(std::string&& key, std::string&& value);
105 : : /**
106 : : * @param[in] key The field-name of the header to search for and delete
107 : : */
108 : : void RemoveAll(std::string_view key);
109 : : /**
110 : : * @param[in] reader A LineReader instance initialized with the client's receive buffer.
111 : : * @param[in] write Whether or not to write the parsed data to the object after validation.
112 : : * @returns false if LineReader hits the end of the buffer before reading an
113 : : * \n, meaning that we are still waiting on more data from the client.
114 : : * true after reading an entire HTTP headers section, terminated
115 : : * by an empty line and \n.
116 : : * @throws on exceeded read limit and on bad headers syntax (e.g. no ":" in a line)
117 : : */
118 : : bool Read(util::LineReader& reader, bool write = true);
119 : : std::string Stringify() const;
120 : :
121 : : private:
122 : : /**
123 : : * Headers can have duplicate field names, so we use a vector of key-value pairs instead of a map.
124 : : * https://httpwg.org/specs/rfc9110.html#rfc.section.5.2
125 : : */
126 : : std::vector<std::pair<std::string, std::string>> m_headers;
127 : :
128 : : //! Track total bytes consumed in Read() for limit checks
129 : : size_t m_consumed{0};
130 : : };
131 : :
132 [ # # ]: 312 : struct HTTPVersion {
133 : : /**
134 : : * Default HTTP protocol version 1.1 is used by error responses
135 : : * when a request is unreadable.
136 : : */
137 : : /// @{
138 : : uint8_t major{1};
139 : : uint8_t minor{1};
140 : : /// @}
141 : : };
142 : :
143 : 0 : struct HTTPResponse {
144 : : HTTPVersion version;
145 : : HTTPStatusCode status{HTTP_INTERNAL_SERVER_ERROR};
146 : : HTTPHeaders headers;
147 : :
148 : : std::string StringifyHeaders() const;
149 : : };
150 : :
151 : : class HTTPRemoteClient;
152 : :
153 : : class HTTPRequest
154 : : {
155 : : public:
156 [ # # ]: 0 : explicit HTTPRequest(const std::shared_ptr<HTTPRemoteClient>& client) : m_client{client} {}
157 : : //! Construct with a null client for unit tests
158 : 312 : explicit HTTPRequest() : m_client{} {}
159 : :
160 : : /**
161 : : * Methods that attempt to parse HTTP request fields line-by-line
162 : : * from a receive buffer.
163 : : * @param[in] reader A LineReader object constructed over a span of data.
164 : : * @returns true If the request field was parsed.
165 : : * false If there was not enough data in the buffer to complete the field.
166 : : * @throws std::runtime_error if data is invalid.
167 : : */
168 : : /// @{
169 : : bool LoadControlData(util::LineReader& reader);
170 : : bool LoadHeaders(util::LineReader& reader);
171 : : bool LoadBody(util::LineReader& reader);
172 : : /// @}
173 : :
174 : : void WriteReply(HTTPStatusCode status, std::span<const std::byte> reply_body = {});
175 : 0 : void WriteReply(HTTPStatusCode status, std::string_view reply_body_view)
176 : : {
177 : 0 : WriteReply(status, std::as_bytes(std::span{reply_body_view}));
178 : 0 : }
179 : :
180 : : const HTTPVersion& GetVersion() const { return m_version; }
181 : : std::shared_ptr<HTTPRemoteClient> GetClient() const { return m_client.lock(); }
182 : :
183 : : // These methods reimplement the API from http_libevent::HTTPRequest
184 : : // for downstream JSONRPC and REST modules.
185 [ - + ]: 188 : std::string GetURI() const { return m_target; }
[ # # # #
# # # # #
# # # # #
# # ]
186 : : CService GetPeer() const;
187 [ # # ][ + - ]: 94 : HTTPRequestMethod GetRequestMethod() const { return m_method; }
[ # # # # ]
188 : : std::optional<std::string> GetQueryParameter(std::string_view key) const;
189 : : std::optional<std::string> GetHeader(std::string_view hdr) const;
190 [ # # # # ]: 188 : std::string ReadBody() const { return m_body; }
[ - + + - ]
191 : : void WriteHeader(std::string&& hdr, std::string&& value);
192 : : std::optional<uint64_t> GetChunkSize() const { return m_chunk_size; }
193 : : uint64_t GetChunkProgress() const { return m_chunk_read; }
194 : :
195 : : enum class State {
196 : : Init,
197 : : NeedsHeaders,
198 : : NeedsBody,
199 : : Complete,
200 : : Error
201 : : };
202 [ # # # # : 0 : State GetState() const { return m_state; }
# # ]
203 : 0 : void SetState(State state) { m_state = state; }
204 : :
205 : : private:
206 : : HTTPRequestMethod m_method;
207 : : std::string m_target;
208 : : HTTPVersion m_version;
209 : : HTTPHeaders m_headers;
210 : : std::string m_body;
211 : :
212 : : //! Pointer to the client that made the request so we know who to respond to.
213 : : std::weak_ptr<HTTPRemoteClient> m_client;
214 : :
215 : : //! Response headers may be set in advance before response body is known
216 : : HTTPHeaders m_response_headers;
217 : :
218 : : // If a large request is sent with "Transfer-encoding: chunked" we may
219 : : // read the chunk size in a separate I/O loop iteration than the chunk
220 : : // of data itself. Store the chunk size value here until the chunk is read.
221 : : std::optional<uint64_t> m_chunk_size;
222 : : // We may also read a large chunk over multiple loop iterations.
223 : : // Track the progress of the chunk here.
224 : : uint64_t m_chunk_read{0};
225 : :
226 : : State m_state = State::Init;
227 : : };
228 : :
229 : : class HTTPServer
230 : : {
231 : : public:
232 : : /**
233 : : * Each connection is assigned an unique id of this type.
234 : : */
235 : : using Id = uint64_t;
236 : :
237 : 0 : explicit HTTPServer(std::function<void(std::unique_ptr<HTTPRequest>&&)> func)
238 [ # # ]: 0 : : m_request_dispatcher{std::move(func)} {}
239 : :
240 : 0 : virtual ~HTTPServer()
241 : 0 : {
242 [ # # ]: 0 : Assume(!m_thread_socket_handler.joinable()); // Missing call to JoinSocketsThreads()
243 [ # # ]: 0 : Assume(m_connected.empty()); // Missing call to DisconnectClients(), or disconnect flags not set
244 [ # # ]: 0 : Assume(m_listen.empty()); // Missing call to StopListening()
245 : 0 : }
246 : :
247 : : /**
248 : : * Parse the user's -rpcallowip settings and populate m_allow_subnets
249 : : */
250 : : bool InitHTTPAllowList();
251 : :
252 : : /**
253 : : * Bind to a new address:port, start listening and add the listen socket to `m_listen`.
254 : : * @param[in] to Where to bind.
255 : : * @returns {} or the reason for failure.
256 : : */
257 : : util::Expected<void, std::string> BindAndStartListening(const CService& to);
258 : :
259 : : /**
260 : : * Stop listening by closing all listening sockets.
261 : : */
262 : : void StopListening();
263 : :
264 : : /**
265 : : * Get the number of sockets the server is bound to and listening on
266 : : */
267 : : size_t GetListeningSocketCount() const { return m_listen.size(); }
268 : :
269 : : /**
270 : : * Get the number of HTTPRemoteClients we are connected to
271 : : */
272 [ # # # # : 0 : size_t GetConnectionsCount() const { return m_connected_size.load(std::memory_order_acquire); }
# # ]
273 : :
274 : : /**
275 : : * Start the necessary threads for sockets IO.
276 : : */
277 : : void StartSocketsThreads();
278 : :
279 : : /**
280 : : * Join (wait for) the threads started by `StartSocketsThreads()` to exit.
281 : : */
282 : : void JoinSocketsThreads();
283 : :
284 : : /**
285 : : * Stop network activity
286 : : */
287 : 0 : void InterruptNet() { m_interrupt_net(); }
288 : :
289 : : /**
290 : : * Start disconnecting clients when possible in the I/O loop
291 : : */
292 : 0 : void DisconnectAllClients() { m_disconnect_all_clients = true; }
293 : :
294 : : /**
295 : : * Update the request handler method.
296 : : * Used for shutdown to reject new requests.
297 : : */
298 : 0 : void SetRequestHandler(std::function<void(std::unique_ptr<HTTPRequest>&&)> func)
299 : : EXCLUSIVE_LOCKS_REQUIRED(!m_request_dispatcher_mutex)
300 : : {
301 [ # # # # ]: 0 : WITH_LOCK(m_request_dispatcher_mutex,
302 : : m_request_dispatcher = std::move(func));
303 : 0 : }
304 : :
305 : : /**
306 : : * Stop accepting new connections in the I/O loop.
307 : : * Must be called first in StopHTTPServer() before DisconnectAllClients().
308 : : * A connection accepted after the "wait for 0 connections" loop exits would
309 : : * remain in m_connected when the destructor is called.
310 : : */
311 : 0 : void StopAccepting() { m_stop_accepting = true; }
312 : :
313 : : /**
314 : : * Set the idle client timeout (-rpcservertimeout)
315 : : */
316 : 0 : void SetServerTimeout(std::chrono::seconds seconds) { m_rpcservertimeout = seconds; }
317 : :
318 : : /**
319 : : * Set the maximum amount of connected HTTPClients (-rpcmaxconnections)
320 : : */
321 : 0 : void SetMaxConnections(int max_conn) { m_rpcmaxconnections = max_conn; }
322 : :
323 : : /**
324 : : * Force-remove all remaining clients from m_connected without waiting for
325 : : * graceful disconnection. Must only be called after JoinSocketsThreads().
326 : : */
327 : : void ClearConnectedClients();
328 : :
329 : : private:
330 : : /**
331 : : * List of listening sockets.
332 : : */
333 : : std::vector<std::shared_ptr<Sock>> m_listen;
334 : :
335 : : /**
336 : : * The id to assign to the next created connection.
337 : : */
338 : : std::atomic<Id> m_next_id{0};
339 : :
340 : : /**
341 : : * List of HTTPRemoteClients with connected sockets.
342 : : * Connections will only be added and removed in the I/O thread, but
343 : : * weak pointers may be passed to worker threads to handle requests
344 : : * and send replies.
345 : : */
346 : : std::vector<std::shared_ptr<HTTPRemoteClient>> m_connected;
347 : :
348 : : /**
349 : : * Flag used during shutdown to stop accepting new connections.
350 : : * Set by main thread and read by the I/O thread.
351 : : */
352 : : std::atomic_bool m_stop_accepting{false};
353 : :
354 : : /**
355 : : * Flag used during shutdown.
356 : : * Overrides HTTPRemoteClient flags m_keep_alive and m_connection_busy.
357 : : * Set by main thread and read by the I/O thread.
358 : : */
359 : : std::atomic_bool m_disconnect_all_clients{false};
360 : :
361 : : /**
362 : : * The number of connected sockets.
363 : : * Updated from the I/O thread but safely readable from
364 : : * the main thread without locks.
365 : : */
366 : : std::atomic<size_t> m_connected_size{0};
367 : :
368 : : /**
369 : : * Info about which socket has which event ready and a reverse map
370 : : * back to the HTTPRemoteClient that owns the socket.
371 : : */
372 [ # # ]: 0 : struct IOReadiness {
373 : : /**
374 : : * Map of socket -> socket events. For example:
375 : : * socket1 -> { requested = SendEvent|RecvEvent, occurred = RecvEvent }
376 : : * socket2 -> { requested = SendEvent, occurred = SendEvent }
377 : : */
378 : : Sock::EventsPerSock events_per_sock;
379 : :
380 : : /**
381 : : * Map of socket -> HTTPRemoteClient. For example:
382 : : * socket1 -> HTTPRemoteClient{ id=23 }
383 : : * socket2 -> HTTPRemoteClient{ id=56 }
384 : : */
385 : : std::unordered_map<Sock::EventsPerSock::key_type,
386 : : std::shared_ptr<HTTPRemoteClient>,
387 : : Sock::HashSharedPtrSock,
388 : : Sock::EqualSharedPtrSock>
389 : : httpclients_per_sock;
390 : : };
391 : :
392 : : /**
393 : : * This is signaled when network activity should cease.
394 : : */
395 : : CThreadInterrupt m_interrupt_net;
396 : :
397 : : /**
398 : : * Thread that sends to and receives from sockets and accepts connections.
399 : : * Executes the I/O loop of the server.
400 : : */
401 : : std::thread m_thread_socket_handler;
402 : :
403 : : /*
404 : : * What to do with HTTP requests once received, validated and parsed.
405 : : * Set in main thread by server start and interrupt but read in
406 : : * worker threads.
407 : : */
408 : : /// @{
409 : : mutable Mutex m_request_dispatcher_mutex;
410 : : std::function<void(std::unique_ptr<HTTPRequest>&&)> m_request_dispatcher GUARDED_BY(m_request_dispatcher_mutex);
411 : : /// @}
412 : :
413 : : /**
414 : : * Idle timeout after which clients are disconnected
415 : : */
416 : : std::chrono::seconds m_rpcservertimeout{DEFAULT_HTTP_SERVER_TIMEOUT};
417 : :
418 : : /**
419 : : * List of subnets to allow HTTP connections from
420 : : */
421 : : std::vector<CSubNet> m_allow_subnets;
422 : :
423 : : /**
424 : : * Check an incoming connection's source IP against the allow list
425 : : */
426 : : bool ClientAllowed(const CNetAddr& netaddr) const;
427 : :
428 : : /**
429 : : * Maximum amount of concurrent connections
430 : : */
431 : : int m_rpcmaxconnections{DEFAULT_MAX_HTTP_CONNECTIONS};
432 : :
433 : : /**
434 : : * Accept a connection.
435 : : * @param[in] listen_sock Socket on which to accept the connection.
436 : : * @param[out] addr Address of the peer that was accepted.
437 : : * @return Newly created socket for the accepted connection.
438 : : */
439 : : std::unique_ptr<Sock> AcceptConnection(const Sock& listen_sock, CService& addr);
440 : :
441 : : /**
442 : : * Generate an id for a newly created connection.
443 : : */
444 : : Id GetNewId();
445 : :
446 : : /**
447 : : * After a new socket with a client has been created, configure its flags,
448 : : * make a new HTTPRemoteClient and Id and save its shared pointer.
449 : : * @param[in] sock The newly created socket.
450 : : * @param[in] addr Address of the new peer.
451 : : */
452 : : void NewSockAccepted(std::unique_ptr<Sock>&& sock, const CService& addr);
453 : :
454 : : /**
455 : : * Do the read/write for connected sockets that are ready for IO.
456 : : * @param[in] io_readiness Which sockets are ready and their corresponding HTTPRemoteClients.
457 : : */
458 : : void SocketHandlerConnected(const IOReadiness& io_readiness) const
459 : : EXCLUSIVE_LOCKS_REQUIRED(!m_request_dispatcher_mutex);
460 : :
461 : : /**
462 : : * Accept incoming connections, one from each read-ready listening socket.
463 : : * @param[in] events_per_sock Sockets that are ready for IO.
464 : : */
465 : : void SocketHandlerListening(const Sock::EventsPerSock& events_per_sock);
466 : :
467 : : /**
468 : : * Generate a collection of sockets to check for IO readiness.
469 : : * @return Sockets to check for readiness plus an aux map to find the
470 : : * corresponding HTTPRemoteClient given a socket.
471 : : */
472 : : IOReadiness GenerateWaitSockets() const;
473 : :
474 : : /**
475 : : * Check connected and listening sockets for IO readiness and process them accordingly.
476 : : * This is the main I/O loop of the server.
477 : : */
478 : : void ThreadSocketHandler() EXCLUSIVE_LOCKS_REQUIRED(!m_request_dispatcher_mutex);
479 : :
480 : : /**
481 : : * Close underlying socket connections for flagged clients
482 : : * by removing their shared pointer from m_connected. If an HTTPRemoteClient
483 : : * is busy in a worker thread, its connection will be closed once that
484 : : * job is done.
485 : : */
486 : : void DisconnectClients();
487 : : };
488 : :
489 : : std::optional<std::string> GetQueryParameterFromUri(std::string_view uri, std::string_view key);
490 : :
491 : : class HTTPRemoteClient
492 : : {
493 : : public:
494 : 0 : explicit HTTPRemoteClient(HTTPServer::Id id, const CService& addr, std::unique_ptr<Sock> socket)
495 [ # # # # ]: 0 : : m_id(id), m_addr(addr), m_origin(addr.ToStringAddrPort()), m_sock{std::move(socket)}, m_idle_since{Now<SteadySeconds>()} {}
496 : :
497 : : // Disable copies (should only be used as shared pointers)
498 : : HTTPRemoteClient(const HTTPRemoteClient&) = delete;
499 : : HTTPRemoteClient& operator=(const HTTPRemoteClient&) = delete;
500 : :
501 : : const std::string& GetOrigin() const { return m_origin; }
502 : 0 : const CService& GetPeer() const { return m_addr; }
503 [ # # # # : 0 : std::shared_ptr<Sock> GetSock() EXCLUSIVE_LOCKS_REQUIRED(!m_sock_mutex) { return WITH_LOCK(m_sock_mutex, return m_sock;); }
# # ]
504 [ # # # # ]: 0 : bool ReadyToSend() const EXCLUSIVE_LOCKS_REQUIRED(!m_send_mutex) { return WITH_LOCK(m_send_mutex, return m_send_ready;); }
505 : :
506 : : void Send(const HTTPResponse& res, std::span<const std::byte> reply_body, bool keep_alive) EXCLUSIVE_LOCKS_REQUIRED(!m_send_mutex, !m_sock_mutex);
507 : : void Receive() EXCLUSIVE_LOCKS_REQUIRED(!m_sock_mutex);
508 : :
509 : : bool MaybeDisconnect(std::chrono::time_point<SteadyClock> now, std::chrono::seconds rpcservertimeout, bool disconnect_all);
510 : :
511 : : /**
512 : : * Try to read an HTTPRequest from a client's receive buffer.
513 : : * Only complete requests are returned, incomplete requests are
514 : : * left in the buffer to wait for more data. Some read errors
515 : : * will mark this client for disconnection.
516 : : */
517 : : static std::unique_ptr<HTTPRequest> TryReadRequest(const std::shared_ptr<HTTPRemoteClient>& client);
518 : :
519 : : /**
520 : : * Push data (if there is any) from client's m_send_buffer to the connected socket.
521 : : * @returns false if we are done with this client and HTTPServer can skip the next read operation from it.
522 : : */
523 : : bool MaybeSendBytesFromBuffer() EXCLUSIVE_LOCKS_REQUIRED(!m_send_mutex, !m_sock_mutex);
524 : :
525 : : //! Used for tests.
526 : : //! @{
527 : : const std::string& GetRecvBuffer() const { return m_recv_buffer; }
528 : : const HTTPRequest* GetRequest() const { return m_req.get(); }
529 : : //! @}
530 : :
531 : : protected:
532 : : //! Used for tests.
533 : : std::string& MutateRecvBuffer() { return m_recv_buffer; }
534 : :
535 : : private:
536 : : /**
537 : : * Try to read an HTTP request from the receive buffer.
538 : : * Updates HTTPRequest.m_state and drains buffer on error.
539 : : * @param[in] req A HTTPRequest to read into
540 : : * @throws std::runtime_error if request is unreadable or violates protocol
541 : : */
542 : : void ReadRequest(HTTPRequest& req);
543 : :
544 : : //! ID provided by HTTPServer upon connection and instantiation
545 : : const HTTPServer::Id m_id;
546 : :
547 : : //! Remote address of connected client
548 : : const CService m_addr;
549 : :
550 : : //! IP:port of connected client, cached for logging purposes
551 : : const std::string m_origin;
552 : :
553 : : /**
554 : : * In lieu of an intermediate transport class like p2p uses,
555 : : * we copy data from the socket buffer to the client object
556 : : * and attempt to read HTTP requests from here.
557 : : */
558 : : std::string m_recv_buffer{};
559 : :
560 : : //! Requests from a client must be processed in the order in which
561 : : //! they were received, blocking on a per-client basis. We read
562 : : //! one request at a time from the socket buffer then pass it to a worker.
563 : : std::unique_ptr<HTTPRequest> m_req;
564 : :
565 : : //! Set to true by the I/O thread when a request is popped off
566 : : //! and passed to a worker thread, reset to false by the worker thread.
567 : : std::atomic_bool m_req_busy{false};
568 : :
569 : : /**
570 : : * Response data destined for this client.
571 : : * Written to by http worker threads, read and erased by HTTPServer I/O thread
572 : : */
573 : : /// @{
574 : : mutable Mutex m_send_mutex;
575 : : std::vector<std::byte> m_send_buffer GUARDED_BY(m_send_mutex);
576 : : /// @}
577 : :
578 : : /**
579 : : * Set true by worker threads after writing a response to m_send_buffer.
580 : : * Set false by the HTTPServer I/O thread after flushing m_send_buffer.
581 : : * Checked in the HTTPServer I/O loop to decide whether to poll the socket for
582 : : * writeability or readability.
583 : : * Guarded by m_send_mutex so it stays consistent with m_send_buffer's emptiness:
584 : : * the two must always be updated together under the same lock.
585 : : */
586 : : bool m_send_ready GUARDED_BY(m_send_mutex){false};
587 : :
588 : : /**
589 : : * Mutex that serializes the Send() and Recv() calls on `m_sock`. Reading
590 : : * from the client occurs in the I/O thread but writing back to a client
591 : : * may occur in a worker thread.
592 : : */
593 : : Mutex m_sock_mutex;
594 : :
595 : : /**
596 : : * Underlying socket.
597 : : * `shared_ptr` (instead of `unique_ptr`) is used to avoid premature close of the
598 : : * underlying file descriptor by one thread while another thread is poll(2)-ing
599 : : * it for activity.
600 : : * @see https://github.com/bitcoin/bitcoin/issues/21744 for details.
601 : : */
602 : : std::shared_ptr<Sock> m_sock GUARDED_BY(m_sock_mutex);
603 : :
604 : : //! Initialized to true while server waits for first request from client.
605 : : //! Set to false after data is written to m_send_buffer and then that buffer is flushed to client.
606 : : //! Reset to true when we receive new request data from client.
607 : : //! Checked during DisconnectClients() and set by read/write operations
608 : : //! called in either the HTTPServer I/O loop or by a worker thread during an "optimistic send".
609 : : //! `m_connection_busy=true` can be overridden by `m_disconnect=true` (we disconnect).
610 : : std::atomic_bool m_connection_busy{true};
611 : :
612 : : //! Client has requested to keep the connection open after all requests have been responded to.
613 : : //! Set by (potentially multiple) worker threads and checked in the HTTPServer I/O loop.
614 : : //! `m_keep_alive=true` can be overridden `by HTTPServer.m_disconnect_all_clients` (we disconnect).
615 : : std::atomic_bool m_keep_alive{false};
616 : :
617 : : //! Flag this client for disconnection on next loop.
618 : : //! Either we have encountered a permanent error, or both sides of the socket are done
619 : : //! with the connection, e.g. our reply to a "Connection: close" request has been sent.
620 : : //! Might be set in a worker thread or in the I/O thread. When set to `true` we disconnect,
621 : : //! possibly overriding all other disconnect flags.
622 : : std::atomic_bool m_disconnect{false};
623 : :
624 : : //! Timestamp of last send or receive activity, used for -rpcservertimeout.
625 : : //! Due to optimistic sends it may be updated in either a worker thread or in the
626 : : //! I/O thread. It is checked in the I/O thread to disconnect idle clients.
627 : : std::atomic<SteadySeconds> m_idle_since;
628 : : };
629 : :
630 : : /** Initialize HTTP server.
631 : : * Call this before RegisterHTTPHandler or EventBase().
632 : : */
633 : : bool InitHTTPServer();
634 : :
635 : : /** Start HTTP server.
636 : : * This is separate from InitHTTPServer to give users race-condition-free time
637 : : * to register their handlers between InitHTTPServer and StartHTTPServer.
638 : : */
639 : : void StartHTTPServer();
640 : :
641 : : /** Interrupt HTTP server threads */
642 : : void InterruptHTTPServer();
643 : :
644 : : /** Stop HTTP server */
645 : : void StopHTTPServer();
646 : :
647 : : #endif // BITCOIN_HTTPSERVER_H
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