From 6fbdbcabc3ae43dc372459c6c5ae4d53657267f5 Mon Sep 17 00:00:00 2001
From: Ed Tanous <edtanous@google.com>
Date: Mon, 6 Dec 2021 14:36:06 -0800
Subject: Implement connection limit

Now that we rely on normal steady_timer, bmcweb doesn't limit http
connections.  This commit moves the connectionCount variable out of the
debug ifdefs, and into the "normal" build.  Then additionally, add a
check to ensure that less than 100 connections are started at a time.
This count is intended to match the code in timer_queue.hpp that limited
this to 100 timers at a given time.

Tested:
/redfish/v1 returns properly.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I93ceaf8319d09d911b36cb7b21bba0cf64a9f7b8
---
 http/http_connection.hpp | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

(limited to 'http/http_connection.hpp')

diff --git a/http/http_connection.hpp b/http/http_connection.hpp
index bfd641154e..06bb63af04 100644
--- a/http/http_connection.hpp
+++ b/http/http_connection.hpp
@@ -35,9 +35,7 @@ inline void prettyPrintJson(crow::Response& res)
     res.addHeader("Content-Type", "text/html;charset=UTF-8");
 }
 
-#ifdef BMCWEB_ENABLE_DEBUG
-static std::atomic<int> connectionCount;
-#endif
+static int connectionCount = 0;
 
 // request body limit size set by the bmcwebHttpReqBodyLimitMb option
 constexpr unsigned int httpReqBodyLimit =
@@ -67,22 +65,20 @@ class Connection :
         prepareMutualTls();
 #endif // BMCWEB_ENABLE_MUTUAL_TLS_AUTHENTICATION
 
-#ifdef BMCWEB_ENABLE_DEBUG
         connectionCount++;
+
         BMCWEB_LOG_DEBUG << this << " Connection open, total "
                          << connectionCount;
-#endif
     }
 
     ~Connection()
     {
         res.setCompleteRequestHandler(nullptr);
         cancelDeadlineTimer();
-#ifdef BMCWEB_ENABLE_DEBUG
+
         connectionCount--;
         BMCWEB_LOG_DEBUG << this << " Connection closed, total "
                          << connectionCount;
-#endif
     }
 
     void prepareMutualTls()
@@ -277,6 +273,12 @@ class Connection :
 
     void start()
     {
+        if (connectionCount >= 100)
+        {
+            BMCWEB_LOG_CRITICAL << this << "Max connection count exceeded.";
+            return;
+        }
+
         startDeadline();
 
         // TODO(ed) Abstract this to a more clever class with the idea of an
-- 
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