curl.h: add CURLOPT_CA_CACHE_TIMEOUT option

Adds a new option to control the maximum time that a cached
certificate store may be retained for.

Currently only the OpenSSL backend implements support for
caching certificate stores.

Closes #9620

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/url.c b/lib/url.c
index 4b26f747b..6774b6b85 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -539,6 +539,8 @@ CURLcode Curl_init_userdefined(struct Curl_easy *data)
 
   /* Set the default size of the SSL session ID cache */
   set->general_ssl.max_ssl_sessions = 5;
+  /* Timeout every 24 hours by default */
+  set->general_ssl.ca_cache_timeout = 24 * 60 * 60;
 
   set->proxyport = 0;
   set->proxytype = CURLPROXY_HTTP; /* defaults to HTTP proxy */