From 40b556d3742a1f65d67e2d4c760d0b13fe8be5b7 Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Fri, 23 Jan 2015 07:53:17 +0100 Subject: evhttpd implementation - *Replace usage of boost::asio with [libevent2](http://libevent.org/)*. boost::asio is not part of C++11, so unlike other boost there is no forwards-compatibility reason to stick with it. Together with #4738 (convert json_spirit to UniValue), this rids Bitcoin Core of the worst offenders with regard to compile-time slowness. - *Replace spit-and-duct-tape http server with evhttp*. Front-end http handling is handled by libevent, a work queue (with configurable depth and parallelism) is used to handle application requests. - *Wrap HTTP request in C++ class*; this makes the application code mostly HTTP-server-neutral - *Refactor RPC to move all http-specific code to a separate file*. Theoreticaly this can allow building without HTTP server but with another RPC backend, e.g. Qt's debug console (currently not implemented) or future RPC mechanisms people may want to use. - *HTTP dispatch mechanism*; services (e.g., RPC, REST) register which URL paths they want to handle. By using a proven, high-performance asynchronous networking library (also used by Tor) and HTTP server, problems such as #5674, #5655, #344 should be avoided. What works? bitcoind, bitcoin-cli, bitcoin-qt. Unit tests and RPC/REST tests pass. The aim for now is everything but SSL support. Configuration options: - `-rpcthreads`: repurposed as "number of work handler threads". Still defaults to 4. - `-rpcworkqueue`: maximum depth of work queue. When this is reached, new requests will return a 500 Internal Error. - `-rpctimeout`: inactivity time, in seconds, after which to disconnect a client. - `-debug=http`: low-level http activity logging --- src/httpserver.cpp | 586 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 586 insertions(+) create mode 100644 src/httpserver.cpp (limited to 'src/httpserver.cpp') diff --git a/src/httpserver.cpp b/src/httpserver.cpp new file mode 100644 index 0000000000..89366b2e4e --- /dev/null +++ b/src/httpserver.cpp @@ -0,0 +1,586 @@ +// Copyright (c) 2015 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#include "httpserver.h" + +#include "chainparamsbase.h" +#include "compat.h" +#include "util.h" +#include "netbase.h" +#include "rpcprotocol.h" // For HTTP status codes +#include "sync.h" +#include "ui_interface.h" + +#include +#include +#include + +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +#ifdef EVENT__HAVE_NETINET_IN_H +#include +#ifdef _XOPEN_SOURCE_EXTENDED +#include +#endif +#endif + +#include // for to_lower() +#include +#include + +/** HTTP request work item */ +class HTTPWorkItem : public HTTPClosure +{ +public: + HTTPWorkItem(HTTPRequest* req, const std::string &path, const HTTPRequestHandler& func): + req(req), path(path), func(func) + { + } + void operator()() + { + func(req.get(), path); + } + + boost::scoped_ptr req; + +private: + std::string path; + HTTPRequestHandler func; +}; + +/** Simple work queue for distributing work over multiple threads. + * Work items are simply callable objects. + */ +template +class WorkQueue +{ +private: + /** Mutex protects entire object */ + CWaitableCriticalSection cs; + CConditionVariable cond; + /* XXX in C++11 we can use std::unique_ptr here and avoid manual cleanup */ + std::deque queue; + bool running; + size_t maxDepth; + +public: + WorkQueue(size_t maxDepth) : running(true), + maxDepth(maxDepth) + { + } + /* Precondition: worker threads have all stopped */ + ~WorkQueue() + { + while (!queue.empty()) { + delete queue.front(); + queue.pop_front(); + } + } + /** Enqueue a work item */ + bool Enqueue(WorkItem* item) + { + boost::unique_lock lock(cs); + if (queue.size() >= maxDepth) { + return false; + } + queue.push_back(item); + cond.notify_one(); + return true; + } + /** Thread function */ + void Run() + { + while (running) { + WorkItem* i = 0; + { + boost::unique_lock lock(cs); + while (running && queue.empty()) + cond.wait(lock); + if (!running) + break; + i = queue.front(); + queue.pop_front(); + } + (*i)(); + delete i; + } + } + /** Interrupt and exit loops */ + void Interrupt() + { + boost::unique_lock lock(cs); + running = false; + cond.notify_all(); + } + + /** Return current depth of queue */ + size_t Depth() + { + boost::unique_lock lock(cs); + return queue.size(); + } +}; + +struct HTTPPathHandler +{ + HTTPPathHandler() {} + HTTPPathHandler(std::string prefix, bool exactMatch, HTTPRequestHandler handler): + prefix(prefix), exactMatch(exactMatch), handler(handler) + { + } + std::string prefix; + bool exactMatch; + HTTPRequestHandler handler; +}; + +/** HTTP module state */ + +//! libevent event loop +static struct event_base* eventBase = 0; +//! HTTP server +struct evhttp* eventHTTP = 0; +//! List of subnets to allow RPC connections from +static std::vector rpc_allow_subnets; +//! Work queue for handling longer requests off the event loop thread +static WorkQueue* workQueue = 0; +//! Handlers for (sub)paths +std::vector pathHandlers; + +/** Check if a network address is allowed to access the HTTP server */ +static bool ClientAllowed(const CNetAddr& netaddr) +{ + if (!netaddr.IsValid()) + return false; + BOOST_FOREACH (const CSubNet& subnet, rpc_allow_subnets) + if (subnet.Match(netaddr)) + return true; + return false; +} + +/** Initialize ACL list for HTTP server */ +static bool InitHTTPAllowList() +{ + rpc_allow_subnets.clear(); + rpc_allow_subnets.push_back(CSubNet("127.0.0.0/8")); // always allow IPv4 local subnet + rpc_allow_subnets.push_back(CSubNet("::1")); // always allow IPv6 localhost + if (mapMultiArgs.count("-rpcallowip")) { + const std::vector& vAllow = mapMultiArgs["-rpcallowip"]; + BOOST_FOREACH (std::string strAllow, vAllow) { + CSubNet subnet(strAllow); + if (!subnet.IsValid()) { + uiInterface.ThreadSafeMessageBox( + strprintf("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), + "", CClientUIInterface::MSG_ERROR); + return false; + } + rpc_allow_subnets.push_back(subnet); + } + } + std::string strAllowed; + BOOST_FOREACH (const CSubNet& subnet, rpc_allow_subnets) + strAllowed += subnet.ToString() + " "; + LogPrint("http", "Allowing HTTP connections from: %s\n", strAllowed); + return true; +} + +/** HTTP request method as string - use for logging only */ +static std::string RequestMethodString(HTTPRequest::RequestMethod m) +{ + switch (m) { + case HTTPRequest::GET: + return "GET"; + break; + case HTTPRequest::POST: + return "POST"; + break; + case HTTPRequest::HEAD: + return "HEAD"; + break; + case HTTPRequest::PUT: + return "PUT"; + break; + default: + return "unknown"; + } +} + +/** HTTP request callback */ +static void http_request_cb(struct evhttp_request* req, void* arg) +{ + std::auto_ptr hreq(new HTTPRequest(req)); + + LogPrint("http", "Received a %s request for %s from %s\n", + RequestMethodString(hreq->GetRequestMethod()), hreq->GetURI(), hreq->GetPeer().ToString()); + + // Early address-based allow check + if (!ClientAllowed(hreq->GetPeer())) { + hreq->WriteReply(HTTP_FORBIDDEN); + return; + } + + // Early reject unknown HTTP methods + if (hreq->GetRequestMethod() == HTTPRequest::UNKNOWN) { + hreq->WriteReply(HTTP_BADMETHOD); + return; + } + + // Find registered handler for prefix + std::string strURI = hreq->GetURI(); + std::string path; + std::vector::const_iterator i = pathHandlers.begin(); + std::vector::const_iterator iend = pathHandlers.end(); + for (; i != iend; ++i) { + bool match = false; + if (i->exactMatch) + match = (strURI == i->prefix); + else + match = (strURI.substr(0, i->prefix.size()) == i->prefix); + if (match) { + path = strURI.substr(i->prefix.size()); + break; + } + } + + // Dispatch to worker thread + if (i != iend) { + std::auto_ptr item(new HTTPWorkItem(hreq.release(), path, i->handler)); + assert(workQueue); + if (workQueue->Enqueue(item.get())) + item.release(); /* if true, queue took ownership */ + else + item->req->WriteReply(HTTP_INTERNAL, "Work queue depth exceeded"); + } else { + hreq->WriteReply(HTTP_NOTFOUND); + } +} + +/** Event dispatcher thread */ +static void ThreadHTTP(struct event_base* base, struct evhttp* http) +{ + RenameThread("bitcoin-http"); + LogPrint("http", "Entering http event loop\n"); + event_base_dispatch(base); + // Event loop will be interrupted by InterruptHTTPServer() + LogPrint("http", "Exited http event loop\n"); +} + +/** Bind HTTP server to specified addresses */ +static bool HTTPBindAddresses(struct evhttp* http) +{ + int defaultPort = GetArg("-rpcport", BaseParams().RPCPort()); + int nBound = 0; + std::vector > endpoints; + + // Determine what addresses to bind to + if (!mapArgs.count("-rpcallowip")) { // Default to loopback if not allowing external IPs + endpoints.push_back(std::make_pair("::1", defaultPort)); + endpoints.push_back(std::make_pair("127.0.0.1", defaultPort)); + if (mapArgs.count("-rpcbind")) { + LogPrintf("WARNING: option -rpcbind was ignored because -rpcallowip was not specified, refusing to allow everyone to connect\n"); + } + } else if (mapArgs.count("-rpcbind")) { // Specific bind address + const std::vector& vbind = mapMultiArgs["-rpcbind"]; + for (std::vector::const_iterator i = vbind.begin(); i != vbind.end(); ++i) { + int port = defaultPort; + std::string host; + SplitHostPort(*i, port, host); + endpoints.push_back(std::make_pair(host, port)); + } + } else { // No specific bind address specified, bind to any + endpoints.push_back(std::make_pair("::", defaultPort)); + endpoints.push_back(std::make_pair("0.0.0.0", defaultPort)); + } + + // Bind addresses + for (std::vector >::iterator i = endpoints.begin(); i != endpoints.end(); ++i) { + LogPrint("http", "Binding RPC on address %s port %i\n", i->first, i->second); + if (evhttp_bind_socket(http, i->first.empty() ? NULL : i->first.c_str(), i->second) == 0) { + nBound += 1; + } else { + LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second); + } + } + return nBound > 0; +} + +/** Simple wrapper to set thread name and run work queue */ +static void HTTPWorkQueueRun(WorkQueue* queue) +{ + RenameThread("bitcoin-httpworker"); + queue->Run(); +} + +bool StartHTTPServer(boost::thread_group& threadGroup) +{ + struct evhttp* http = 0; + struct event_base* base = 0; + + if (!InitHTTPAllowList()) + return false; + + if (GetBoolArg("-rpcssl", false)) { + uiInterface.ThreadSafeMessageBox( + "SSL mode for RPC (-rpcssl) is no longer supported.", + "", CClientUIInterface::MSG_ERROR); + return false; + } + +#ifdef WIN32 + evthread_use_windows_threads(); +#else + evthread_use_pthreads(); +#endif + + base = event_base_new(); // XXX RAII + if (!base) { + LogPrintf("Couldn't create an event_base: exiting\n"); + return false; + } + + /* Create a new evhttp object to handle requests. */ + http = evhttp_new(base); // XXX RAII + if (!http) { + LogPrintf("couldn't create evhttp. Exiting.\n"); + event_base_free(base); + return false; + } + + evhttp_set_timeout(http, GetArg("-rpctimeout", 30)); + evhttp_set_max_body_size(http, MAX_SIZE); + evhttp_set_gencb(http, http_request_cb, NULL); + + if (!HTTPBindAddresses(http)) { + LogPrintf("Unable to bind any endpoint for RPC server\n"); + evhttp_free(http); + event_base_free(base); + return false; + } + + LogPrint("http", "Starting HTTP server\n"); + int workQueueDepth = std::max((long)GetArg("-rpcworkqueue", 16), 1L); + int rpcThreads = std::max((long)GetArg("-rpcthreads", 4), 1L); + LogPrintf("HTTP: creating work queue of depth %d and %d worker threads\n", workQueueDepth, rpcThreads); + workQueue = new WorkQueue(workQueueDepth); + + threadGroup.create_thread(boost::bind(&ThreadHTTP, base, http)); + + for (int i = 0; i < rpcThreads; i++) + threadGroup.create_thread(boost::bind(&HTTPWorkQueueRun, workQueue)); + + eventBase = base; + eventHTTP = http; + return true; +} + +void InterruptHTTPServer() +{ + LogPrint("http", "Interrupting HTTP server\n"); + if (eventBase) + event_base_loopbreak(eventBase); + if (workQueue) + workQueue->Interrupt(); +} + +void StopHTTPServer() +{ + LogPrint("http", "Stopping HTTP server\n"); + delete workQueue; + if (eventHTTP) { + evhttp_free(eventHTTP); + eventHTTP = 0; + } + if (eventBase) { + event_base_free(eventBase); + eventBase = 0; + } +} + +struct event_base* EventBase() +{ + return eventBase; +} + +static void httpevent_callback_fn(evutil_socket_t, short, void* data) +{ + // Static handler simply passes through execution flow to _handle method + ((HTTPEvent*)data)->_handle(); +} + +void HTTPEvent::_handle() +{ + (*handler)(); + if (deleteWhenTriggered) + delete this; +} + +HTTPEvent::HTTPEvent(struct event_base* base, bool deleteWhenTriggered, HTTPClosure* handler) : deleteWhenTriggered(deleteWhenTriggered), handler(handler) +{ + ev = event_new(base, -1, 0, httpevent_callback_fn, this); + assert(ev); +} +HTTPEvent::~HTTPEvent() +{ + event_free(ev); +} +void HTTPEvent::trigger(struct timeval* tv) +{ + if (tv == NULL) + event_active(ev, 0, 0); // immediately trigger event in main thread + else + evtimer_add(ev, tv); // trigger after timeval passed +} +HTTPRequest::HTTPRequest(struct evhttp_request* req) : req(req), + replySent(false) +{ +} +HTTPRequest::~HTTPRequest() +{ + if (!replySent) { + // Keep track of whether reply was sent to avoid request leaks + LogPrintf("%s: Unhandled request\n", __func__); + WriteReply(HTTP_INTERNAL, "Unhandled request"); + } + // evhttpd cleans up the request, as long as a reply was sent. +} + +std::pair HTTPRequest::GetHeader(const std::string& hdr) +{ + const struct evkeyvalq* headers = evhttp_request_get_input_headers(req); + assert(headers); + const char* val = evhttp_find_header(headers, hdr.c_str()); + if (val) + return std::make_pair(true, val); + else + return std::make_pair(false, ""); +} + +std::string HTTPRequest::ReadBody() +{ + struct evbuffer* buf = evhttp_request_get_input_buffer(req); + if (!buf) + return ""; + size_t size = evbuffer_get_length(buf); + /** Trivial implementation: if this is ever a performance bottleneck, + * internal copying can be avoided in multi-segment buffers by using + * evbuffer_peek and an awkward loop. Though in that case, it'd be even + * better to not copy into an intermediate string but use a stream + * abstraction to consume the evbuffer on the fly in the parsing algorithm. + */ + const char* data = (const char*)evbuffer_pullup(buf, size); + if (!data) // returns NULL in case of empty buffer + return ""; + std::string rv(data, size); + evbuffer_drain(buf, size); + return rv; +} + +void HTTPRequest::WriteHeader(const std::string& hdr, const std::string& value) +{ + struct evkeyvalq* headers = evhttp_request_get_output_headers(req); + assert(headers); + evhttp_add_header(headers, hdr.c_str(), value.c_str()); +} + +/** Closure sent to main thread to request a reply to be sent to + * a HTTP request. + * Replies must be sent in the main loop in the main http thread, + * this cannot be done from worker threads. + */ +struct HTTPSendReplyHandler : HTTPClosure { +public: + HTTPSendReplyHandler(struct evhttp_request* req, int nStatus) : req(req), nStatus(nStatus) + { + } + void operator()() + { + evhttp_send_reply(req, nStatus, NULL, NULL); + } +private: + struct evhttp_request* req; + int nStatus; +}; + +void HTTPRequest::WriteReply(int nStatus, const std::string& strReply) +{ + assert(!replySent && req); + // Send event to main http thread to send reply message + struct evbuffer* evb = evhttp_request_get_output_buffer(req); + assert(evb); + evbuffer_add(evb, strReply.data(), strReply.size()); + HTTPEvent* ev = new HTTPEvent(eventBase, true, + new HTTPSendReplyHandler(req, nStatus)); + ev->trigger(0); + replySent = true; + req = 0; // transferred back to main thread +} + +CService HTTPRequest::GetPeer() +{ + evhttp_connection* con = evhttp_request_get_connection(req); + CService peer; + if (con) { + // evhttp retains ownership over returned address string + const char* address = ""; + uint16_t port = 0; + evhttp_connection_get_peer(con, (char**)&address, &port); + peer = CService(address, port); + } + return peer; +} + +std::string HTTPRequest::GetURI() +{ + return evhttp_request_get_uri(req); +} + +HTTPRequest::RequestMethod HTTPRequest::GetRequestMethod() +{ + switch (evhttp_request_get_command(req)) { + case EVHTTP_REQ_GET: + return GET; + break; + case EVHTTP_REQ_POST: + return POST; + break; + case EVHTTP_REQ_HEAD: + return HEAD; + break; + case EVHTTP_REQ_PUT: + return PUT; + break; + default: + return UNKNOWN; + break; + } +} + +void RegisterHTTPHandler(const std::string &prefix, bool exactMatch, const HTTPRequestHandler &handler) +{ + LogPrint("http", "Registering HTTP handler for %s (exactmath %d)\n", prefix, exactMatch); + pathHandlers.push_back(HTTPPathHandler(prefix, exactMatch, handler)); +} + +void UnregisterHTTPHandler(const std::string &prefix, bool exactMatch) +{ + std::vector::iterator i = pathHandlers.begin(); + std::vector::iterator iend = pathHandlers.end(); + for (; i != iend; ++i) + if (i->prefix == prefix && i->exactMatch == exactMatch) + break; + if (i != iend) + { + LogPrint("http", "Unregistering HTTP handler for %s (exactmath %d)\n", prefix, exactMatch); + pathHandlers.erase(i); + } +} + -- cgit v1.2.3