Hi Daniel,
On Fri, Jan 03, 2020 at 09:21:04PM +0100, Daniel Jeliński via curl-library
wrote:
> Hi all,
> I see that libcurl supports SSL session ID cache already, unless
> CURLOPT_SSL_SESSIONID_CACHE is cleared. However, I'm having a hard
> time finding information about the scope of session ID reuse:
> - Are session IDs reused only within an easy handle or globally for
> all handles within the application?
It looks like it is reused within an easy handle only. The attached
program was based on the output of:
curl --http1.1 -vIH connection:close https://example.com/
https://example.com/ --libcurl some.c
With `cc some.c -lcurl`, I see "SSL re-using session ID" in stderr.
With `cc some.c -lcurl -DRESET`, I do not see that line.
> - Does libcurl keep a mapping between host names and session IDs? As
> far as I can tell, openSSL does not.
It appears so. Aside from hostname, the port number, and TLS config
(client cert, certificate validation, etc.) are also checked:
https://github.com/curl/curl/blob/curl-7_67_0/lib/vtls/vtls.c#L344-L353
For OpenSSL, the relevant glue code is here:
https://github.com/curl/curl/blob/curl-7_67_0/lib/vtls/openssl.c#L2864-L2875
--
Kind regards,
Peter Wu
https://lekensteyn.nl
#include <curl/curl.h>
int main(int argc, char *argv[])
{
CURLcode ret;
CURL *hnd;
struct curl_slist *slist1;
struct curl_slist *slist2;
slist1 = NULL;
slist1 = curl_slist_append(slist1, "connection:close");
slist2 = NULL;
slist2 = curl_slist_append(slist2, "connection:close");
hnd = curl_easy_init();
curl_easy_setopt(hnd, CURLOPT_URL, "https://example.com/";);
curl_easy_setopt(hnd, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(hnd, CURLOPT_NOBODY, 1L);
curl_easy_setopt(hnd, CURLOPT_HTTPHEADER, slist1);
curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, (long)CURL_HTTP_VERSION_1_1);
curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);
ret = curl_easy_perform(hnd);
#ifdef RESET
curl_easy_cleanup(hnd);
hnd = curl_easy_init();
#endif
curl_easy_setopt(hnd, CURLOPT_URL, "https://www.example.com/";);
curl_easy_setopt(hnd, CURLOPT_NOPROGRESS, 1L);
curl_easy_setopt(hnd, CURLOPT_NOBODY, 1L);
curl_easy_setopt(hnd, CURLOPT_HTTPHEADER, slist2);
curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, (long)CURL_HTTP_VERSION_1_1);
curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);
ret = curl_easy_perform(hnd);
curl_easy_cleanup(hnd);
hnd = NULL;
curl_slist_free_all(slist1);
slist1 = NULL;
curl_slist_free_all(slist2);
slist2 = NULL;
return (int)ret;
}
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