Implement NetworkManager

For now there are two methods: - `NETWORK:IsUrlAllowed()`: Check whether access to a certain URL is allowed. - `NETWORK:HttpRequest()`: Perform an HTTP request. By default access to the network is disabled for all target hosts. It can be enabled by setting `HttpEnable=1` in the preferences. Individual hosts have to be added to `HttpAllowHosts` as a comma separated list to allow access. See included docs for more details on usage.
2022-01-15 22:56:08 +01:00
parent ddfc49e0b5
commit dc49af3c59
265 changed files with 61571 additions and 0 deletions
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+/*
+ *  IXDNSLookup.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2018 Machine Zone, Inc. All rights reserved.
+ */
+
+//
+// On Windows Universal Platform (uwp), gai_strerror defaults behavior is to returns wchar_t
+// which is different from all other platforms. We want the non unicode version.
+// See https://github.com/microsoft/vcpkg/pull/11030
+// We could do this in IXNetSystem.cpp but so far we are only using gai_strerror in here.
+//
+#ifdef _UNICODE
+#undef _UNICODE
+#endif
+#ifdef UNICODE
+#undef UNICODE
+#endif
+
+#include "IXDNSLookup.h"
+
+#include "IXNetSystem.h"
+#include <chrono>
+#include <string.h>
+#include <thread>
+
+// mingw build quirks
+#if defined(_WIN32) && defined(__GNUC__)
+#define AI_NUMERICSERV NI_NUMERICSERV
+#define AI_ADDRCONFIG LUP_ADDRCONFIG
+#endif
+
+namespace ix
+{
+    const int64_t DNSLookup::kDefaultWait = 1; // ms
+
+    DNSLookup::DNSLookup(const std::string& hostname, int port, int64_t wait)
+        : _hostname(hostname)
+        , _port(port)
+        , _wait(wait)
+        , _res(nullptr)
+        , _done(false)
+    {
+        ;
+    }
+
+    struct addrinfo* DNSLookup::getAddrInfo(const std::string& hostname,
+                                            int port,
+                                            std::string& errMsg)
+    {
+        struct addrinfo hints;
+        memset(&hints, 0, sizeof(hints));
+        hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
+        hints.ai_family = AF_UNSPEC;
+        hints.ai_socktype = SOCK_STREAM;
+
+        std::string sport = std::to_string(port);
+
+        struct addrinfo* res;
+        int getaddrinfo_result = getaddrinfo(hostname.c_str(), sport.c_str(), &hints, &res);
+        if (getaddrinfo_result)
+        {
+            errMsg = gai_strerror(getaddrinfo_result);
+            res = nullptr;
+        }
+        return res;
+    }
+
+    struct addrinfo* DNSLookup::resolve(std::string& errMsg,
+                                        const CancellationRequest& isCancellationRequested,
+                                        bool cancellable)
+    {
+        return cancellable ? resolveCancellable(errMsg, isCancellationRequested)
+                           : resolveUnCancellable(errMsg, isCancellationRequested);
+    }
+
+    void DNSLookup::release(struct addrinfo* addr)
+    {
+        freeaddrinfo(addr);
+    }
+
+    struct addrinfo* DNSLookup::resolveUnCancellable(
+        std::string& errMsg, const CancellationRequest& isCancellationRequested)
+    {
+        errMsg = "no error";
+
+        // Maybe a cancellation request got in before the background thread terminated ?
+        if (isCancellationRequested())
+        {
+            errMsg = "cancellation requested";
+            return nullptr;
+        }
+
+        return getAddrInfo(_hostname, _port, errMsg);
+    }
+
+    struct addrinfo* DNSLookup::resolveCancellable(
+        std::string& errMsg, const CancellationRequest& isCancellationRequested)
+    {
+        errMsg = "no error";
+
+        // Can only be called once, otherwise we would have to manage a pool
+        // of background thread which is overkill for our usage.
+        if (_done)
+        {
+            return nullptr; // programming error, create a second DNSLookup instance
+                            // if you need a second lookup.
+        }
+
+        //
+        // Good resource on thread forced termination
+        // https://www.bo-yang.net/2017/11/19/cpp-kill-detached-thread
+        //
+        auto ptr = shared_from_this();
+        std::weak_ptr<DNSLookup> self(ptr);
+
+        int port = _port;
+        std::string hostname(_hostname);
+
+        // We make the background thread doing the work a shared pointer
+        // instead of a member variable, because it can keep running when
+        // this object goes out of scope, in case of cancellation
+        auto t = std::make_shared<std::thread>(&DNSLookup::run, this, self, hostname, port);
+        t->detach();
+
+        while (!_done)
+        {
+            // Wait for 1 milliseconds, to see if the bg thread has terminated.
+            // We do not use a condition variable to wait, as destroying this one
+            // if the bg thread is alive can cause undefined behavior.
+            std::this_thread::sleep_for(std::chrono::milliseconds(_wait));
+
+            // Were we cancelled ?
+            if (isCancellationRequested())
+            {
+                errMsg = "cancellation requested";
+                return nullptr;
+            }
+        }
+
+        // Maybe a cancellation request got in before the bg terminated ?
+        if (isCancellationRequested())
+        {
+            errMsg = "cancellation requested";
+            return nullptr;
+        }
+
+        errMsg = getErrMsg();
+        return getRes();
+    }
+
+    void DNSLookup::run(std::weak_ptr<DNSLookup> self,
+                        std::string hostname,
+                        int port) // thread runner
+    {
+        // We don't want to read or write into members variables of an object that could be
+        // gone, so we use temporary variables (res) or we pass in by copy everything that
+        // getAddrInfo needs to work.
+        std::string errMsg;
+        struct addrinfo* res = getAddrInfo(hostname, port, errMsg);
+
+        if (auto lock = self.lock())
+        {
+            // Copy result into the member variables
+            setRes(res);
+            setErrMsg(errMsg);
+
+            _done = true;
+        }
+    }
+
+    void DNSLookup::setErrMsg(const std::string& errMsg)
+    {
+        std::lock_guard<std::mutex> lock(_errMsgMutex);
+        _errMsg = errMsg;
+    }
+
+    const std::string& DNSLookup::getErrMsg()
+    {
+        std::lock_guard<std::mutex> lock(_errMsgMutex);
+        return _errMsg;
+    }
+
+    void DNSLookup::setRes(struct addrinfo* addr)
+    {
+        std::lock_guard<std::mutex> lock(_resMutex);
+        _res = addr;
+    }
+
+    struct addrinfo* DNSLookup::getRes()
+    {
+        std::lock_guard<std::mutex> lock(_resMutex);
+        return _res;
+    }
+} // namespace ix