Allow to run NDT over Tor (#15)

* Start adding support for NDT over Tor

* curlx_test.cpp: fix test I have broken

Now init() is idempotent in the proper sense, while before the
behavior was consistent but possibly not idempotent.

* Revert small, unnecessary change

* libndt.cpp: fix MSVC 32 bit build

* Repair build

* revamp socks5 code

* libndt.cpp: attempt to fix windows build

* Write tests to cover more curlx methods

* Add one more simple test

* libndt_test: use connect_tcp_maybe_socks5()

Of course, where it makes sense.

* Start adding more tests for socks5h

* Repair build error

* More tests for socks5 code

* Fix previous

* Add some more tests

* More socks5 tests

* more tests

* improve tests

* add two more tests

* Remove unused methods

* Final changes before merging

curlx.cpp

@@ -42,6 +42,25 @@ void CurlDeleter::operator()(CURL *handle) noexcept {
 
 Curl::Curl() noexcept {}
 
+bool Curl::method_get_maybe_socks5(const std::string &proxy_port,
+                                   const std::string &url, long timeout,
+                                   std::string *body,
+                                   std::string *err) noexcept {
+  if (!init()) {
+    *err = "cannot initialize cURL";
+    return false;
+  }
+  if (!proxy_port.empty()) {
+    std::stringstream ss;
+    ss << "socks5h://127.0.0.1:" << proxy_port;
+    if (setopt_proxy(ss.str()) != CURLE_OK) {
+      *err = "cannot set proxy";
+      return false;
+    }
+  }
+  return method_get(url, timeout, body, err);
+}
+
 bool Curl::method_get(const std::string &url, long timeout, std::string *body,
                       std::string *err) noexcept {
   if (body == nullptr || err == nullptr) {
@@ -80,7 +99,7 @@ bool Curl::method_get(const std::string &url, long timeout, std::string *body,
 
 bool Curl::init() noexcept {
   if (!!handle_) {
-    return false;
+    return true; // make the method idempotent
   }
   auto handle = this->easy_init();
   if (!handle) {
@@ -95,6 +114,11 @@ CURLcode Curl::setopt_url(const std::string &url) noexcept {
   return ::curl_easy_setopt(handle_.get(), CURLOPT_URL, url.c_str());
 }
 
+CURLcode Curl::setopt_proxy(const std::string &url) noexcept {
+  assert(handle_);
+  return ::curl_easy_setopt(handle_.get(), CURLOPT_PROXY, url.c_str());
+}
+
 CURLcode Curl::setopt_writefunction(size_t (*callback)(
     char *ptr, size_t size, size_t nmemb, void *userdata)) noexcept {
   assert(handle_);

curlx.hpp

@@ -26,6 +26,10 @@ class Curl {
 
   Curl() noexcept;
 
+  bool method_get_maybe_socks5(const std::string &proxy_port,
+                               const std::string &url, long timeout,
+                               std::string *body, std::string *err) noexcept;
+
   bool method_get(const std::string &url, long timeout, std::string *body,
                   std::string *err) noexcept;
 
@@ -35,6 +39,8 @@ class Curl {
 
   virtual CURLcode setopt_url(const std::string &url) noexcept;
 
+  virtual CURLcode setopt_proxy(const std::string &url) noexcept;
+
   virtual CURLcode setopt_writefunction(size_t (*callback)(
       char *ptr, size_t size, size_t nmemb, void *userdata)) noexcept;
 

curlx_test.cpp

@@ -9,6 +9,40 @@
 
 using namespace measurement_kit;
 
+// Curl::method_get_maybe_socks5() tests
+// -------------------------------------
+
+class FailInit : public libndt::Curl {
+ public:
+  using libndt::Curl::Curl;
+  virtual bool init() noexcept override { return false; }
+};
+
+TEST_CASE("Curl::method_get_maybe_socks5() deals with Curl::init() failure") {
+  FailInit curl;
+  std::string body;
+  std::string err;
+  REQUIRE(!curl.method_get_maybe_socks5("", "http://x.org", 1, &body, &err));
+}
+
+class FailSetoptProxy : public libndt::Curl {
+ public:
+  using libndt::Curl::Curl;
+  virtual CURLcode setopt_proxy(const std::string &) noexcept override {
+    return CURLE_UNSUPPORTED_PROTOCOL; // any error is okay here
+  }
+};
+
+TEST_CASE(
+    "Curl::method_get_maybe_socks5() deals with Curl::setopt_proxy() failure") {
+  FailSetoptProxy curl;
+  std::string body;
+  std::string err;
+  REQUIRE(
+      !curl.method_get_maybe_socks5("9050", "http://x.org", 1, &body, &err));
+  REQUIRE(err == "cannot set proxy");
+}
+
 // Curl::method_get() tests
 // ------------------------
 
@@ -24,12 +58,6 @@ TEST_CASE("Curl::method_get() deals with null err") {
   REQUIRE(curl.method_get("http://x.org", 1, &body, nullptr) == false);
 }
 
-class FailInit : public libndt::Curl {
- public:
-  using libndt::Curl::Curl;
-  virtual bool init() noexcept override { return false; }
-};
-
 TEST_CASE("Curl::method_get() deals with Curl::init() failure") {
   FailInit curl;
   std::string body;
@@ -129,7 +157,16 @@ TEST_CASE("Curl::init() deals with curl_easy_init() failure") {
 TEST_CASE("Curl::init() is idempotent") {
   libndt::Curl curl;
   REQUIRE(curl.init() == true);
-  REQUIRE(curl.init() == false);
+  REQUIRE(curl.init() == true);
+}
+
+// Curl::setopt_proxy() tests
+// --------------------------
+
+TEST_CASE("Curl::setopt_proxy() works") {
+  libndt::Curl curl;
+  REQUIRE(curl.init() == true);
+  REQUIRE(curl.setopt_proxy("socks5h://127.0.0.1:9050") == CURLE_OK);
 }
 
 #endif  // HAVE_CURL

libndt-client.cpp

@@ -20,6 +20,8 @@ static void usage() {
   std::clog << "  --download-ext        : run multi-stream download test\n";
   std::clog << "  --json                : use the JSON protocol\n";
   std::clog << "  --port <port>         : use the specified port\n";
+  std::clog
+      << "  --socks5h <port>      : use socks5h proxy at 127.0.0.1:<port>\n";
   std::clog << "  --upload              : run upload test\n";
   std::clog << "  --verbose             : be verbose\n";
   std::clog << "\n";
@@ -31,11 +33,12 @@ int main(int, char **argv) {
   using namespace measurement_kit;
   libndt::Settings settings;
   settings.verbosity = libndt::verbosity::quiet;
-  settings.test_suite = 0; // you need to enable tests explicitly
+  settings.test_suite = 0;  // you need to enable tests explicitly
 
   {
     argh::parser cmdline;
     cmdline.add_param("port");
+    cmdline.add_param("socks5h");
     cmdline.parse(argv);
     for (auto &flag : cmdline.flags()) {
       if (flag == "download") {
@@ -63,6 +66,10 @@ int main(int, char **argv) {
       if (param.first == "port") {
         settings.port = param.second;
         std::clog << "will use port: " << param.second << std::endl;
+      } else if (param.first == "socks5h") {
+        settings.socks5h_port = param.second;
+        std::clog << "will use socks5h proxy at: 127.0.0.1:" << param.second
+                  << std::endl;
       } else {
         std::clog << "fatal: unrecognized param: " << param.first << std::endl;
         usage();