[release/6.x] Cherry-pick: Reuse curl handle to attempt to reuse sessions (#7321) (#7332)

Co-authored-by: cjen1-msft <chrisjensen@microsoft.com>

Author: achamayou

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [6.0.16]
+
+[6.0.16]: https://github.com/microsoft/CCF/releases/tag/6.0.16
+
+### Changed
+
+- Snapshot fetching attempts to re-use the TLS sessions whenever possible (#7321)
+
 ## [6.0.15]
 
 [6.0.15]: https://github.com/microsoft/CCF/releases/tag/6.0.15

python/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ccf"
-version = "6.0.15"
+version = "6.0.16"
 authors = [
   { name="CCF Team", email="CCF-Sec@microsoft.com" },
 ]

src/http/curl.h

@@ -63,6 +63,20 @@ namespace ccf::curl
       }
     }
 
+    // No implicit copying: unique ownership of the CURL handle
+    UniqueCURL(const UniqueCURL&) = delete;
+    UniqueCURL& operator=(const UniqueCURL&) = delete;
+
+    // Move semantics
+    UniqueCURL(UniqueCURL&& other) noexcept : p(std::move(other.p)) {}
+    UniqueCURL& operator=(UniqueCURL&& other) noexcept
+    {
+      p = std::move(other.p);
+      return *this;
+    }
+
+    ~UniqueCURL() = default;
+
     operator CURL*() const
     {
       return p.get();
@@ -493,6 +507,11 @@ namespace ccf::curl
       return curl_handle;
     }
 
+    [[nodiscard]] UniqueCURL& get_easy_handle_ptr()
+    {
+      return curl_handle;
+    }
+
     [[nodiscard]] RESTVerb get_method() const
     {
       return method;

src/snapshots/fetch.h

@@ -50,8 +50,8 @@ namespace snapshots
       // Make initial request, which returns a redirect response to specific
       // snapshot
       std::string snapshot_url;
+      ccf::curl::UniqueCURL curl_easy;
       {
-        ccf::curl::UniqueCURL curl_easy;
         curl_easy.set_opt(CURLOPT_CAINFO, path_to_peer_cert.c_str());
 
         auto initial_url = fmt::format(
@@ -117,12 +117,12 @@ namespace snapshots
 
         snapshot_url =
           fmt::format("https://{}{}", peer_address, location_it->second);
+        curl_easy = std::move(request->get_easy_handle_ptr());
       }
 
       // Make follow-up request to redirected URL, to fetch total content size
       size_t content_size = 0;
       {
-        ccf::curl::UniqueCURL curl_easy;
         curl_easy.set_opt(CURLOPT_CAINFO, path_to_peer_cert.c_str());
 
         ccf::curl::UniqueSlist headers;
@@ -194,6 +194,7 @@ namespace snapshots
             snapshot_size_request->get_url(),
             ec));
         }
+        curl_easy = std::move(snapshot_size_request->get_easy_handle_ptr());
       }
 
       // Fetch 4MB chunks at a time
@@ -212,7 +213,6 @@ namespace snapshots
 
         while (true)
         {
-          ccf::curl::UniqueCURL curl_easy;
           curl_easy.set_opt(CURLOPT_CAINFO, path_to_peer_cert.c_str());
 
           ccf::curl::UniqueSlist headers;
@@ -266,6 +266,7 @@ namespace snapshots
 
           snapshot_response =
             std::move(snapshot_range_request->get_response_ptr());
+          curl_easy = std::move(snapshot_range_request->get_easy_handle_ptr());
 
           if (range_end == content_size)
           {