add SSL_get0_iana_groups() & SSL_client_hello_get_extension_order()

The function/macro allow user get groups/extensions without memory allcations.
So we could calculate the ssl fignerprint(ja3) in low cost.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16910)

1 files changed, 8 insertions, 0 deletions

diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 120b5cedeb..3b3cc8a32a 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3729,6 +3729,14 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
             return (int)s->ext.peer_ecpointformats_len;
         }
 
+    case SSL_CTRL_GET_IANA_GROUPS:
+        {
+            if (parg != NULL) {
+                *(uint16_t **)parg = (uint16_t *)s->ext.peer_supportedgroups;
+            }
+            return (int)s->ext.peer_supportedgroups_len;
+        }
+
     default:
         break;
     }