Line data Source code
1 : // Copyright (c) 2015-2021 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 : #if defined(HAVE_CONFIG_H)
6 : #include <config/bitcoin-config.h>
7 : #endif
8 :
9 : #include <httpserver.h>
10 :
11 : #include <chainparamsbase.h>
12 : #include <netbase.h>
13 : #include <node/interface_ui.h>
14 : #include <rpc/protocol.h> // For HTTP status codes
15 : #include <shutdown.h>
16 : #include <sync.h>
17 : #include <util/check.h>
18 : #include <util/strencodings.h>
19 : #include <util/system.h>
20 : #include <util/threadnames.h>
21 : #include <util/translation.h>
22 :
23 : #include <cstdio>
24 : #include <deque>
25 : #include <optional>
26 : #include <string>
27 : #include <unordered_map>
28 :
29 : #include <sys/types.h>
30 :
31 : #include <event2/buffer.h>
32 : #include <event2/bufferevent.h>
33 : #include <event2/http.h>
34 : #include <event2/http_struct.h>
35 : #include <event2/keyvalq_struct.h>
36 : #include <event2/thread.h>
37 : #include <event2/util.h>
38 :
39 : #include <support/events.h>
40 :
41 : #include <thread>
42 : #include <condition_variable>
43 :
44 : /** Maximum size of http request (request line + headers) */
45 : static const size_t MAX_HEADERS_SIZE = 8192;
46 :
47 : /** HTTP request work item */
48 : class HTTPWorkItem final : public HTTPClosure
49 : {
50 : public:
51 0 : HTTPWorkItem(std::unique_ptr<HTTPRequest> _req, const std::string &_path, const HTTPRequestHandler& _func):
52 0 : req(std::move(_req)), path(_path), func(_func)
53 0 : {
54 0 : }
55 0 : void operator()() override
56 : {
57 0 : func(req.get(), path);
58 0 : }
59 :
60 : std::unique_ptr<HTTPRequest> req;
61 :
62 : private:
63 : std::string path;
64 : HTTPRequestHandler func;
65 : };
66 :
67 : /** Simple work queue for distributing work over multiple threads.
68 : * Work items are simply callable objects.
69 : */
70 : template <typename WorkItem>
71 : class WorkQueue
72 : {
73 : private:
74 : Mutex cs;
75 : std::condition_variable cond GUARDED_BY(cs);
76 : std::deque<std::unique_ptr<WorkItem>> queue GUARDED_BY(cs);
77 : std::deque<std::unique_ptr<WorkItem>> external_queue GUARDED_BY(cs);
78 0 : bool running GUARDED_BY(cs){true};
79 : const size_t maxDepth;
80 : const size_t m_external_depth;
81 :
82 : public:
83 0 : explicit WorkQueue(size_t _maxDepth, size_t external_depth) :
84 0 : maxDepth(_maxDepth), m_external_depth(external_depth)
85 0 : {
86 0 : }
87 : /** Precondition: worker threads have all stopped (they have been joined).
88 : */
89 0 : ~WorkQueue() = default;
90 : /** Enqueue a work item */
91 0 : bool Enqueue(WorkItem* item, bool is_external) EXCLUSIVE_LOCKS_REQUIRED(!cs)
92 : {
93 0 : LOCK(cs);
94 0 : if (!running) {
95 0 : return false;
96 : }
97 0 : if (is_external) {
98 0 : if (external_queue.size() >= m_external_depth) return false;
99 0 : external_queue.emplace_back(std::unique_ptr<WorkItem>(item));
100 0 : } else {
101 0 : if (queue.size() >= maxDepth) return false;
102 0 : queue.emplace_back(std::unique_ptr<WorkItem>(item));
103 : }
104 0 : cond.notify_one();
105 0 : return true;
106 0 : }
107 : /** Thread function */
108 0 : void Run() EXCLUSIVE_LOCKS_REQUIRED(!cs)
109 : {
110 0 : while (true) {
111 0 : std::unique_ptr<WorkItem> i;
112 : {
113 0 : WAIT_LOCK(cs, lock);
114 0 : while (running && external_queue.empty() && queue.empty())
115 0 : cond.wait(lock);
116 0 : if (!running && external_queue.empty() && queue.empty())
117 0 : break;
118 0 : if (!queue.empty()) {
119 0 : i = std::move(queue.front());
120 0 : queue.pop_front();
121 0 : } else {
122 0 : i = std::move(external_queue.front());
123 0 : external_queue.pop_front();
124 0 : LogPrintf("HTTP: Calling handler for external user...\n");
125 : }
126 0 : }
127 0 : (*i)();
128 0 : }
129 0 : }
130 : /** Interrupt and exit loops */
131 0 : void Interrupt() EXCLUSIVE_LOCKS_REQUIRED(!cs)
132 : {
133 0 : LOCK(cs);
134 0 : running = false;
135 0 : cond.notify_all();
136 0 : }
137 : };
138 :
139 : struct HTTPPathHandler
140 : {
141 0 : HTTPPathHandler(std::string _prefix, bool _exactMatch, HTTPRequestHandler _handler):
142 0 : prefix(_prefix), exactMatch(_exactMatch), handler(_handler)
143 0 : {
144 0 : }
145 : std::string prefix;
146 : bool exactMatch;
147 : HTTPRequestHandler handler;
148 : };
149 :
150 : /** HTTP module state */
151 :
152 : //! libevent event loop
153 : static struct event_base* eventBase = nullptr;
154 : //! HTTP server
155 : static struct evhttp* eventHTTP = nullptr;
156 : //! List of subnets to allow RPC connections from
157 : static std::vector<CSubNet> rpc_allow_subnets;
158 : //! Work queue for handling longer requests off the event loop thread
159 : static std::unique_ptr<WorkQueue<HTTPClosure>> g_work_queue{nullptr};
160 : //! List of 'external' RPC users (global variable, used by httprpc)
161 : std::vector<std::string> g_external_usernames;
162 : //! Handlers for (sub)paths
163 : static GlobalMutex g_httppathhandlers_mutex;
164 : static std::vector<HTTPPathHandler> pathHandlers GUARDED_BY(g_httppathhandlers_mutex);
165 : //! Bound listening sockets
166 : static std::vector<evhttp_bound_socket *> boundSockets;
167 :
168 : /**
169 : * @brief Helps keep track of open `evhttp_connection`s with active `evhttp_requests`
170 : *
171 : */
172 : class HTTPRequestTracker
173 : {
174 : private:
175 : mutable Mutex m_mutex;
176 : mutable std::condition_variable m_cv;
177 : //! For each connection, keep a counter of how many requests are open
178 : std::unordered_map<const evhttp_connection*, size_t> m_tracker GUARDED_BY(m_mutex);
179 :
180 0 : void RemoveConnectionInternal(const decltype(m_tracker)::iterator it) EXCLUSIVE_LOCKS_REQUIRED(m_mutex)
181 : {
182 0 : m_tracker.erase(it);
183 0 : if (m_tracker.empty()) m_cv.notify_all();
184 0 : }
185 : public:
186 : //! Increase request counter for the associated connection by 1
187 0 : void AddRequest(evhttp_request* req) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
188 : {
189 0 : const evhttp_connection* conn{Assert(evhttp_request_get_connection(Assert(req)))};
190 0 : WITH_LOCK(m_mutex, ++m_tracker[conn]);
191 0 : }
192 : //! Decrease request counter for the associated connection by 1, remove connection if counter is 0
193 0 : void RemoveRequest(evhttp_request* req) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
194 : {
195 0 : const evhttp_connection* conn{Assert(evhttp_request_get_connection(Assert(req)))};
196 0 : LOCK(m_mutex);
197 0 : auto it{m_tracker.find(conn)};
198 0 : if (it != m_tracker.end() && it->second > 0) {
199 0 : if (--(it->second) == 0) RemoveConnectionInternal(it);
200 0 : }
201 0 : }
202 : //! Remove a connection entirely
203 0 : void RemoveConnection(const evhttp_connection* conn) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
204 : {
205 0 : LOCK(m_mutex);
206 0 : auto it{m_tracker.find(Assert(conn))};
207 0 : if (it != m_tracker.end()) RemoveConnectionInternal(it);
208 0 : }
209 0 : size_t CountActiveConnections() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
210 : {
211 0 : return WITH_LOCK(m_mutex, return m_tracker.size());
212 : }
213 : //! Wait until there are no more connections with active requests in the tracker
214 0 : void WaitUntilEmpty() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
215 : {
216 0 : WAIT_LOCK(m_mutex, lock);
217 0 : m_cv.wait(lock, [this]() EXCLUSIVE_LOCKS_REQUIRED(m_mutex) { return m_tracker.empty(); });
218 0 : }
219 : };
220 : //! Track active requests
221 146 : static HTTPRequestTracker g_requests;
222 :
223 : /** Check if a network address is allowed to access the HTTP server */
224 0 : static bool ClientAllowed(const CNetAddr& netaddr)
225 : {
226 0 : if (!netaddr.IsValid())
227 0 : return false;
228 0 : for(const CSubNet& subnet : rpc_allow_subnets)
229 0 : if (subnet.Match(netaddr))
230 0 : return true;
231 0 : return false;
232 0 : }
233 :
234 : /** Initialize ACL list for HTTP server */
235 0 : static bool InitHTTPAllowList()
236 : {
237 0 : rpc_allow_subnets.clear();
238 0 : rpc_allow_subnets.emplace_back(LookupHost("127.0.0.1", false).value(), 8); // always allow IPv4 local subnet
239 0 : rpc_allow_subnets.emplace_back(LookupHost("::1", false).value()); // always allow IPv6 localhost
240 0 : for (const std::string& strAllow : gArgs.GetArgs("-rpcallowip")) {
241 0 : const CSubNet subnet{LookupSubNet(strAllow)};
242 0 : if (!subnet.IsValid()) {
243 0 : uiInterface.ThreadSafeMessageBox(
244 0 : strprintf(Untranslated("Invalid -rpcallowip subnet specification: %s. Valid are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24)."), strAllow),
245 0 : "", CClientUIInterface::MSG_ERROR);
246 0 : return false;
247 : }
248 0 : rpc_allow_subnets.push_back(subnet);
249 0 : }
250 0 : std::string strAllowed;
251 0 : for (const CSubNet& subnet : rpc_allow_subnets)
252 0 : strAllowed += subnet.ToString() + " ";
253 0 : LogPrint(BCLog::HTTP, "Allowing HTTP connections from: %s\n", strAllowed);
254 0 : return true;
255 0 : }
256 :
257 : /** HTTP request method as string - use for logging only */
258 0 : std::string RequestMethodString(HTTPRequest::RequestMethod m)
259 : {
260 0 : switch (m) {
261 : case HTTPRequest::GET:
262 0 : return "GET";
263 : case HTTPRequest::POST:
264 0 : return "POST";
265 : case HTTPRequest::HEAD:
266 0 : return "HEAD";
267 : case HTTPRequest::PUT:
268 0 : return "PUT";
269 : case HTTPRequest::UNKNOWN:
270 0 : return "unknown";
271 : } // no default case, so the compiler can warn about missing cases
272 0 : assert(false);
273 0 : }
274 :
275 : /** HTTP request callback */
276 0 : static void http_request_cb(struct evhttp_request* req, void* arg)
277 : {
278 0 : evhttp_connection* conn{evhttp_request_get_connection(req)};
279 : // Track active requests
280 : {
281 0 : g_requests.AddRequest(req);
282 0 : evhttp_request_set_on_complete_cb(req, [](struct evhttp_request* req, void*) {
283 0 : g_requests.RemoveRequest(req);
284 0 : }, nullptr);
285 0 : evhttp_connection_set_closecb(conn, [](evhttp_connection* conn, void* arg) {
286 0 : g_requests.RemoveConnection(conn);
287 0 : }, nullptr);
288 : }
289 :
290 : // Disable reading to work around a libevent bug, fixed in 2.1.9
291 : // See https://github.com/libevent/libevent/commit/5ff8eb26371c4dc56f384b2de35bea2d87814779
292 : // and https://github.com/bitcoin/bitcoin/pull/11593.
293 0 : if (event_get_version_number() >= 0x02010600 && event_get_version_number() < 0x02010900) {
294 0 : if (conn) {
295 0 : bufferevent* bev = evhttp_connection_get_bufferevent(conn);
296 0 : if (bev) {
297 0 : bufferevent_disable(bev, EV_READ);
298 0 : }
299 0 : }
300 0 : }
301 0 : auto hreq{std::make_unique<HTTPRequest>(req)};
302 :
303 : // Early address-based allow check
304 0 : if (!ClientAllowed(hreq->GetPeer())) {
305 0 : LogPrint(BCLog::HTTP, "HTTP request from %s rejected: Client network is not allowed RPC access\n",
306 : hreq->GetPeer().ToStringAddrPort());
307 0 : hreq->WriteReply(HTTP_FORBIDDEN);
308 0 : return;
309 : }
310 :
311 : // Early reject unknown HTTP methods
312 0 : if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) {
313 0 : LogPrint(BCLog::HTTP, "HTTP request from %s rejected: Unknown HTTP request method\n",
314 : hreq->GetPeer().ToStringAddrPort());
315 0 : hreq->WriteReply(HTTP_BAD_METHOD);
316 0 : return;
317 : }
318 :
319 0 : LogPrint(BCLog::HTTP, "Received a %s request for %s from %s\n",
320 : RequestMethodString(hreq->GetRequestMethod()), SanitizeString(hreq->GetURI(), SAFE_CHARS_URI).substr(0, 100), hreq->GetPeer().ToStringAddrPort());
321 :
322 : // Find registered handler for prefix
323 0 : std::string strURI = hreq->GetURI();
324 0 : std::string path;
325 0 : LOCK(g_httppathhandlers_mutex);
326 0 : std::vector<HTTPPathHandler>::const_iterator i = pathHandlers.begin();
327 0 : std::vector<HTTPPathHandler>::const_iterator iend = pathHandlers.end();
328 0 : for (; i != iend; ++i) {
329 0 : bool match = false;
330 0 : if (i->exactMatch)
331 0 : match = (strURI == i->prefix);
332 : else
333 0 : match = (strURI.substr(0, i->prefix.size()) == i->prefix);
334 0 : if (match) {
335 0 : path = strURI.substr(i->prefix.size());
336 0 : break;
337 : }
338 0 : }
339 0 : const bool is_external_request = [&hreq]() -> bool {
340 0 : if (g_external_usernames.empty()) return false;
341 :
342 0 : const std::string strAuth = hreq->GetHeader("authorization").second;
343 0 : if (strAuth.substr(0, 6) != "Basic ")
344 0 : return false;
345 :
346 0 : std::string strUserPass64 = TrimString(strAuth.substr(6));
347 0 : auto opt_strUserPass = DecodeBase64(strUserPass64);
348 0 : if (!opt_strUserPass.has_value()) return false;
349 0 : auto it = std::find(opt_strUserPass->begin(), opt_strUserPass->end(), ':');
350 0 : if (it == opt_strUserPass->end()) return false;
351 0 : const std::string username = std::string(opt_strUserPass->begin(), it);
352 0 : return find(g_external_usernames.begin(), g_external_usernames.end(), username) != g_external_usernames.end();
353 0 : }();
354 :
355 : // Dispatch to worker thread
356 0 : if (i != iend) {
357 0 : auto item{std::make_unique<HTTPWorkItem>(std::move(hreq), path, i->handler)};
358 0 : assert(g_work_queue);
359 :
360 0 : if (g_work_queue->Enqueue(item.get(), is_external_request)) {
361 0 : item.release(); /* if true, queue took ownership */
362 0 : } else {
363 0 : if (is_external_request)
364 : {
365 0 : LogPrintf("WARNING: request rejected because http work queue depth of externals exceeded, it can be increased with the -rpcexternalworkqueue= setting\n");
366 0 : item->req->WriteReply(HTTP_SERVICE_UNAVAILABLE, "Work queue depth of externals exceeded");
367 0 : } else {
368 0 : LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
369 0 : item->req->WriteReply(HTTP_SERVICE_UNAVAILABLE, "Work queue depth exceeded");
370 : }
371 : }
372 0 : } else {
373 0 : hreq->WriteReply(HTTP_NOT_FOUND);
374 : }
375 0 : }
376 :
377 : /** Callback to reject HTTP requests after shutdown. */
378 0 : static void http_reject_request_cb(struct evhttp_request* req, void*)
379 : {
380 0 : LogPrint(BCLog::HTTP, "Rejecting request while shutting down\n");
381 0 : evhttp_send_error(req, HTTP_SERVUNAVAIL, nullptr);
382 0 : }
383 :
384 : /** Event dispatcher thread */
385 0 : static void ThreadHTTP(struct event_base* base)
386 : {
387 0 : util::ThreadRename("http");
388 0 : LogPrint(BCLog::HTTP, "Entering http event loop\n");
389 0 : event_base_dispatch(base);
390 : // Event loop will be interrupted by InterruptHTTPServer()
391 0 : LogPrint(BCLog::HTTP, "Exited http event loop\n");
392 0 : }
393 :
394 : /** Bind HTTP server to specified addresses */
395 0 : static bool HTTPBindAddresses(struct evhttp* http)
396 : {
397 0 : uint16_t http_port{static_cast<uint16_t>(gArgs.GetIntArg("-rpcport", BaseParams().RPCPort()))};
398 0 : std::vector<std::pair<std::string, uint16_t>> endpoints;
399 :
400 : // Determine what addresses to bind to
401 0 : if (!(gArgs.IsArgSet("-rpcallowip") && gArgs.IsArgSet("-rpcbind"))) { // Default to loopback if not allowing external IPs
402 0 : endpoints.emplace_back("::1", http_port);
403 0 : endpoints.emplace_back("127.0.0.1", http_port);
404 0 : if (gArgs.IsArgSet("-rpcallowip")) {
405 0 : LogPrintf("WARNING: option -rpcallowip was specified without -rpcbind; this doesn't usually make sense\n");
406 0 : }
407 0 : if (gArgs.IsArgSet("-rpcbind")) {
408 0 : LogPrintf("WARNING: option -rpcbind was ignored because -rpcallowip was not specified, refusing to allow everyone to connect\n");
409 0 : }
410 0 : } else if (gArgs.IsArgSet("-rpcbind")) { // Specific bind address
411 0 : for (const std::string& strRPCBind : gArgs.GetArgs("-rpcbind")) {
412 0 : uint16_t port{http_port};
413 0 : std::string host;
414 0 : SplitHostPort(strRPCBind, port, host);
415 0 : endpoints.emplace_back(host, port);
416 0 : }
417 0 : } else { // No specific bind address specified, bind to any
418 0 : endpoints.push_back(std::make_pair("::", http_port));
419 0 : endpoints.push_back(std::make_pair("0.0.0.0", http_port));
420 : }
421 :
422 : // Bind addresses
423 0 : for (std::vector<std::pair<std::string, uint16_t> >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) {
424 0 : LogPrintf("Binding RPC on address %s port %i\n", i->first, i->second);
425 0 : evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? nullptr : i->first.c_str(), i->second);
426 0 : if (bind_handle) {
427 0 : const std::optional<CNetAddr> addr{LookupHost(i->first, false)};
428 0 : if (i->first.empty() || (addr.has_value() && addr->IsBindAny())) {
429 0 : LogPrintf("WARNING: the RPC server is not safe to expose to untrusted networks such as the public internet\n");
430 0 : }
431 0 : boundSockets.push_back(bind_handle);
432 0 : } else {
433 0 : LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second);
434 : }
435 0 : }
436 0 : return !boundSockets.empty();
437 0 : }
438 :
439 : /** Simple wrapper to set thread name and run work queue */
440 0 : static void HTTPWorkQueueRun(WorkQueue<HTTPClosure>* queue, int worker_num)
441 : {
442 0 : util::ThreadRename(strprintf("httpworker.%i", worker_num));
443 0 : queue->Run();
444 0 : }
445 :
446 : /** libevent event log callback */
447 0 : static void libevent_log_cb(int severity, const char *msg)
448 : {
449 : BCLog::Level level;
450 0 : switch (severity) {
451 : case EVENT_LOG_DEBUG:
452 0 : level = BCLog::Level::Debug;
453 0 : break;
454 : case EVENT_LOG_MSG:
455 0 : level = BCLog::Level::Info;
456 0 : break;
457 : case EVENT_LOG_WARN:
458 0 : level = BCLog::Level::Warning;
459 0 : break;
460 : default: // EVENT_LOG_ERR and others are mapped to error
461 0 : level = BCLog::Level::Error;
462 0 : break;
463 : }
464 0 : LogPrintLevel(BCLog::LIBEVENT, level, "%s\n", msg);
465 0 : }
466 :
467 0 : bool InitHTTPServer()
468 : {
469 0 : if (!InitHTTPAllowList())
470 0 : return false;
471 :
472 : // Redirect libevent's logging to our own log
473 0 : event_set_log_callback(&libevent_log_cb);
474 : // Update libevent's log handling.
475 0 : UpdateHTTPServerLogging(LogInstance().WillLogCategory(BCLog::LIBEVENT));
476 :
477 : #ifdef WIN32
478 : evthread_use_windows_threads();
479 : #else
480 0 : evthread_use_pthreads();
481 : #endif
482 :
483 0 : raii_event_base base_ctr = obtain_event_base();
484 :
485 : /* Create a new evhttp object to handle requests. */
486 0 : raii_evhttp http_ctr = obtain_evhttp(base_ctr.get());
487 0 : struct evhttp* http = http_ctr.get();
488 0 : if (!http) {
489 0 : LogPrintf("couldn't create evhttp. Exiting.\n");
490 0 : return false;
491 : }
492 :
493 0 : evhttp_set_timeout(http, gArgs.GetIntArg("-rpcservertimeout", DEFAULT_HTTP_SERVER_TIMEOUT));
494 0 : evhttp_set_max_headers_size(http, MAX_HEADERS_SIZE);
495 0 : evhttp_set_max_body_size(http, MAX_SIZE);
496 0 : evhttp_set_gencb(http, http_request_cb, nullptr);
497 :
498 0 : if (!HTTPBindAddresses(http)) {
499 0 : LogPrintf("Unable to bind any endpoint for RPC server\n");
500 0 : return false;
501 : }
502 :
503 0 : LogPrint(BCLog::HTTP, "Initialized HTTP server\n");
504 0 : int workQueueDepth = std::max((long)gArgs.GetIntArg("-rpcworkqueue", DEFAULT_HTTP_WORKQUEUE), 1L);
505 0 : int workQueueDepthExternal = 0;
506 0 : if (const std::string rpc_externaluser{gArgs.GetArg("-rpcexternaluser", "")}; !rpc_externaluser.empty()) {
507 0 : workQueueDepthExternal = std::max((long)gArgs.GetIntArg("-rpcexternalworkqueue", DEFAULT_HTTP_WORKQUEUE), 1L);
508 0 : g_external_usernames = SplitString(rpc_externaluser, ',');
509 0 : }
510 0 : LogDebug(BCLog::HTTP, "creating work queue of depth %d external_depth %d\n", workQueueDepth, workQueueDepthExternal);
511 0 : g_work_queue = std::make_unique<WorkQueue<HTTPClosure>>(workQueueDepth, workQueueDepthExternal);
512 : // transfer ownership to eventBase/HTTP via .release()
513 0 : eventBase = base_ctr.release();
514 0 : eventHTTP = http_ctr.release();
515 0 : return true;
516 0 : }
517 :
518 0 : void UpdateHTTPServerLogging(bool enable) {
519 0 : if (enable) {
520 0 : event_enable_debug_logging(EVENT_DBG_ALL);
521 0 : } else {
522 0 : event_enable_debug_logging(EVENT_DBG_NONE);
523 : }
524 0 : }
525 :
526 146 : static std::thread g_thread_http;
527 : static std::vector<std::thread> g_thread_http_workers;
528 :
529 0 : void StartHTTPServer()
530 : {
531 0 : int rpcThreads = std::max((long)gArgs.GetIntArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
532 0 : LogInfo("Starting HTTP server with %d worker threads\n", rpcThreads);
533 0 : g_thread_http = std::thread(ThreadHTTP, eventBase);
534 :
535 0 : for (int i = 0; i < rpcThreads; i++) {
536 0 : g_thread_http_workers.emplace_back(HTTPWorkQueueRun, g_work_queue.get(), i);
537 0 : }
538 0 : }
539 :
540 0 : void InterruptHTTPServer()
541 : {
542 0 : LogPrint(BCLog::HTTP, "Interrupting HTTP server\n");
543 0 : if (eventHTTP) {
544 : // Reject requests on current connections
545 0 : evhttp_set_gencb(eventHTTP, http_reject_request_cb, nullptr);
546 0 : }
547 0 : if (g_work_queue) {
548 0 : g_work_queue->Interrupt();
549 0 : }
550 0 : }
551 :
552 0 : void StopHTTPServer()
553 : {
554 0 : LogPrint(BCLog::HTTP, "Stopping HTTP server\n");
555 0 : if (g_work_queue) {
556 0 : LogPrint(BCLog::HTTP, "Waiting for HTTP worker threads to exit\n");
557 0 : for (auto& thread : g_thread_http_workers) {
558 0 : thread.join();
559 : }
560 0 : g_thread_http_workers.clear();
561 0 : }
562 : // Unlisten sockets, these are what make the event loop running, which means
563 : // that after this and all connections are closed the event loop will quit.
564 0 : for (evhttp_bound_socket *socket : boundSockets) {
565 0 : evhttp_del_accept_socket(eventHTTP, socket);
566 : }
567 0 : boundSockets.clear();
568 : {
569 0 : if (const auto n_connections{g_requests.CountActiveConnections()}; n_connections != 0) {
570 0 : LogPrint(BCLog::HTTP, "Waiting for %d connections to stop HTTP server\n", n_connections);
571 0 : }
572 0 : g_requests.WaitUntilEmpty();
573 : }
574 0 : if (eventHTTP) {
575 : // Schedule a callback to call evhttp_free in the event base thread, so
576 : // that evhttp_free does not need to be called again after the handling
577 : // of unfinished request connections that follows.
578 0 : event_base_once(eventBase, -1, EV_TIMEOUT, [](evutil_socket_t, short, void*) {
579 0 : evhttp_free(eventHTTP);
580 0 : eventHTTP = nullptr;
581 0 : }, nullptr, nullptr);
582 0 : }
583 0 : if (eventBase) {
584 0 : LogPrint(BCLog::HTTP, "Waiting for HTTP event thread to exit\n");
585 0 : if (g_thread_http.joinable()) g_thread_http.join();
586 0 : event_base_free(eventBase);
587 0 : eventBase = nullptr;
588 0 : }
589 0 : g_work_queue.reset();
590 0 : LogPrint(BCLog::HTTP, "Stopped HTTP server\n");
591 0 : }
592 :
593 0 : struct event_base* EventBase()
594 : {
595 0 : return eventBase;
596 : }
597 :
598 0 : static void httpevent_callback_fn(evutil_socket_t, short, void* data)
599 : {
600 : // Static handler: simply call inner handler
601 0 : HTTPEvent *self = static_cast<HTTPEvent*>(data);
602 0 : self->handler();
603 0 : if (self->deleteWhenTriggered)
604 0 : delete self;
605 0 : }
606 :
607 0 : HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void()>& _handler):
608 0 : deleteWhenTriggered(_deleteWhenTriggered), handler(_handler)
609 0 : {
610 0 : ev = event_new(base, -1, 0, httpevent_callback_fn, this);
611 0 : assert(ev);
612 0 : }
613 0 : HTTPEvent::~HTTPEvent()
614 0 : {
615 0 : event_free(ev);
616 0 : }
617 0 : void HTTPEvent::trigger(struct timeval* tv)
618 : {
619 0 : if (tv == nullptr)
620 0 : event_active(ev, 0, 0); // immediately trigger event in main thread
621 : else
622 0 : evtimer_add(ev, tv); // trigger after timeval passed
623 0 : }
624 0 : HTTPRequest::HTTPRequest(struct evhttp_request* _req, bool _replySent) : req(_req), replySent(_replySent)
625 0 : {
626 0 : }
627 :
628 0 : HTTPRequest::~HTTPRequest()
629 0 : {
630 0 : if (!replySent) {
631 : // Keep track of whether reply was sent to avoid request leaks
632 0 : LogPrintf("%s: Unhandled request\n", __func__);
633 0 : WriteReply(HTTP_INTERNAL_SERVER_ERROR, "Unhandled request");
634 0 : }
635 : // evhttpd cleans up the request, as long as a reply was sent.
636 0 : }
637 :
638 0 : std::pair<bool, std::string> HTTPRequest::GetHeader(const std::string& hdr) const
639 : {
640 0 : const struct evkeyvalq* headers = evhttp_request_get_input_headers(req);
641 0 : assert(headers);
642 0 : const char* val = evhttp_find_header(headers, hdr.c_str());
643 0 : if (val)
644 0 : return std::make_pair(true, val);
645 : else
646 0 : return std::make_pair(false, "");
647 0 : }
648 :
649 0 : std::string HTTPRequest::ReadBody()
650 : {
651 0 : struct evbuffer* buf = evhttp_request_get_input_buffer(req);
652 0 : if (!buf)
653 0 : return "";
654 0 : size_t size = evbuffer_get_length(buf);
655 : /** Trivial implementation: if this is ever a performance bottleneck,
656 : * internal copying can be avoided in multi-segment buffers by using
657 : * evbuffer_peek and an awkward loop. Though in that case, it'd be even
658 : * better to not copy into an intermediate string but use a stream
659 : * abstraction to consume the evbuffer on the fly in the parsing algorithm.
660 : */
661 0 : const char* data = (const char*)evbuffer_pullup(buf, size);
662 0 : if (!data) // returns nullptr in case of empty buffer
663 0 : return "";
664 0 : std::string rv(data, size);
665 0 : evbuffer_drain(buf, size);
666 0 : return rv;
667 0 : }
668 :
669 0 : void HTTPRequest::WriteHeader(const std::string& hdr, const std::string& value)
670 : {
671 0 : struct evkeyvalq* headers = evhttp_request_get_output_headers(req);
672 0 : assert(headers);
673 0 : evhttp_add_header(headers, hdr.c_str(), value.c_str());
674 0 : }
675 :
676 : /** Closure sent to main thread to request a reply to be sent to
677 : * a HTTP request.
678 : * Replies must be sent in the main loop in the main http thread,
679 : * this cannot be done from worker threads.
680 : */
681 0 : void HTTPRequest::WriteReply(int nStatus, const std::string& strReply)
682 : {
683 0 : assert(!replySent && req);
684 0 : if (ShutdownRequested()) {
685 0 : WriteHeader("Connection", "close");
686 0 : }
687 : // Send event to main http thread to send reply message
688 0 : struct evbuffer* evb = evhttp_request_get_output_buffer(req);
689 0 : assert(evb);
690 0 : evbuffer_add(evb, strReply.data(), strReply.size());
691 0 : auto req_copy = req;
692 0 : HTTPEvent* ev = new HTTPEvent(eventBase, true, [req_copy, nStatus]{
693 0 : evhttp_send_reply(req_copy, nStatus, nullptr, nullptr);
694 : // Re-enable reading from the socket. This is the second part of the libevent
695 : // workaround above.
696 0 : if (event_get_version_number() >= 0x02010600 && event_get_version_number() < 0x02010900) {
697 0 : evhttp_connection* conn = evhttp_request_get_connection(req_copy);
698 0 : if (conn) {
699 0 : bufferevent* bev = evhttp_connection_get_bufferevent(conn);
700 0 : if (bev) {
701 0 : bufferevent_enable(bev, EV_READ | EV_WRITE);
702 0 : }
703 0 : }
704 0 : }
705 0 : });
706 0 : ev->trigger(nullptr);
707 0 : replySent = true;
708 0 : req = nullptr; // transferred back to main thread
709 0 : }
710 :
711 0 : CService HTTPRequest::GetPeer() const
712 : {
713 0 : evhttp_connection* con = evhttp_request_get_connection(req);
714 0 : CService peer;
715 0 : if (con) {
716 : // evhttp retains ownership over returned address string
717 0 : const char* address = "";
718 0 : uint16_t port = 0;
719 :
720 : #ifdef HAVE_EVHTTP_CONNECTION_GET_PEER_CONST_CHAR
721 : evhttp_connection_get_peer(con, &address, &port);
722 : #else
723 0 : evhttp_connection_get_peer(con, (char**)&address, &port);
724 : #endif // HAVE_EVHTTP_CONNECTION_GET_PEER_CONST_CHAR
725 :
726 0 : peer = MaybeFlipIPv6toCJDNS(LookupNumeric(address, port));
727 0 : }
728 0 : return peer;
729 0 : }
730 :
731 0 : std::string HTTPRequest::GetURI() const
732 : {
733 0 : return evhttp_request_get_uri(req);
734 : }
735 :
736 0 : HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod() const
737 : {
738 0 : switch (evhttp_request_get_command(req)) {
739 : case EVHTTP_REQ_GET:
740 0 : return GET;
741 : case EVHTTP_REQ_POST:
742 0 : return POST;
743 : case EVHTTP_REQ_HEAD:
744 0 : return HEAD;
745 : case EVHTTP_REQ_PUT:
746 0 : return PUT;
747 : default:
748 0 : return UNKNOWN;
749 : }
750 0 : }
751 :
752 0 : std::optional<std::string> HTTPRequest::GetQueryParameter(const std::string& key) const
753 : {
754 0 : const char* uri{evhttp_request_get_uri(req)};
755 :
756 0 : return GetQueryParameterFromUri(uri, key);
757 : }
758 :
759 7 : std::optional<std::string> GetQueryParameterFromUri(const char* uri, const std::string& key)
760 : {
761 7 : evhttp_uri* uri_parsed{evhttp_uri_parse(uri)};
762 7 : const char* query{evhttp_uri_get_query(uri_parsed)};
763 7 : std::optional<std::string> result;
764 :
765 7 : if (query) {
766 : // Parse the query string into a key-value queue and iterate over it
767 : struct evkeyvalq params_q;
768 5 : evhttp_parse_query_str(query, ¶ms_q);
769 :
770 7 : for (struct evkeyval* param{params_q.tqh_first}; param != nullptr; param = param->next.tqe_next) {
771 6 : if (param->key == key) {
772 4 : result = param->value;
773 4 : break;
774 : }
775 2 : }
776 5 : evhttp_clear_headers(¶ms_q);
777 5 : }
778 7 : evhttp_uri_free(uri_parsed);
779 :
780 7 : return result;
781 7 : }
782 :
783 0 : void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler)
784 : {
785 0 : LogPrint(BCLog::HTTP, "Registering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
786 0 : LOCK(g_httppathhandlers_mutex);
787 0 : pathHandlers.emplace_back(prefix, exactMatch, handler);
788 0 : }
789 :
790 0 : void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch)
791 : {
792 0 : LOCK(g_httppathhandlers_mutex);
793 0 : std::vector<HTTPPathHandler>::iterator i = pathHandlers.begin();
794 0 : std::vector<HTTPPathHandler>::iterator iend = pathHandlers.end();
795 0 : for (; i != iend; ++i)
796 0 : if (i->prefix == prefix && i->exactMatch == exactMatch)
797 0 : break;
798 0 : if (i != iend)
799 : {
800 0 : LogPrint(BCLog::HTTP, "Unregistering HTTP handler for %s (exactmatch %d)\n", prefix, exactMatch);
801 0 : pathHandlers.erase(i);
802 0 : }
803 0 : }
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