Add HTTP strict tranport security support to QNAM

HTTP Strict Transport Security (HSTS) is a web security policy that
allows a web server to declare that user agents should only interact
with it using secure HTTPS connections. HSTS is described by RFC6797.

This patch introduces a new API in Network Access Manager to enable
this policy or disable it (default - STS is disabled).

We also implement QHstsCache which caches known HTTS hosts, does
host name lookup and domain name matching; QHstsHeaderParser to
parse HSTS headers with HSTS policies.

A new autotest added to test the caching, host name matching
and headers parsing.

[ChangeLog][QtNetwork] Added HTTP Strict Transport Security to QNAM

Task-number: QTPM-238
Change-Id: Iabb5920344bf204a0d3036284f0d60675c29315c
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/network/access/qnetworkreply.cpp b/src/network/access/qnetworkreply.cpp
index 17990f02f5..ca27e66791 100644
--- a/src/network/access/qnetworkreply.cpp
+++ b/src/network/access/qnetworkreply.cpp
@@ -732,7 +732,11 @@ void QNetworkReply::setSslConfiguration(const QSslConfiguration &config)
     You can clear the list of errors you want to ignore by calling this
     function with an empty list.
 
-    \sa sslConfiguration(), sslErrors(), QSslSocket::ignoreSslErrors()
+    \note If HTTP Strict Transport Security is enabled for QNetworkAccessManager,
+    this function has no effect.
+
+    \sa sslConfiguration(), sslErrors(), QSslSocket::ignoreSslErrors(),
+    QNetworkAccessManager::enableStrictTransportSecurity()
 */
 void QNetworkReply::ignoreSslErrors(const QList<QSslError> &errors)
 {
@@ -799,6 +803,9 @@ void QNetworkReply::ignoreSslErrorsImplementation(const QList<QSslError> &)
     sslErrors() signal, which indicates which errors were
     found.
 
+    \note If HTTP Strict Transport Security is enabled for QNetworkAccessManager,
+    this function has no effect.
+
     \sa sslConfiguration(), sslErrors(), QSslSocket::ignoreSslErrors()
 */
 void QNetworkReply::ignoreSslErrors()