Add support for reference counting using C11 atomics

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>

GH: #1500

ssl/ssl_cert.c

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 9d35957..f26e876 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -235,7 +235,7 @@
     if (c == NULL)
         return;
 
-    CRYPTO_atomic_add(&c->references, -1, &i, c->lock);
+    CRYPTO_DOWN_REF(&c->references, &i, c->lock);
     REF_PRINT_COUNT("CERT", c);
     if (i > 0)
         return;

ssl/ssl_lib.c

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index b6f7015..5f2c941 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -682,7 +682,7 @@
 {
     int i;
 
-    if (CRYPTO_atomic_add(&s->references, 1, &i, s->lock) <= 0)
+    if (CRYPTO_UP_REF(&s->references, &i, s->lock) <= 0)
         return 0;
 
     REF_PRINT_COUNT("SSL", s);
@@ -965,7 +965,7 @@
     if (s == NULL)
         return;
 
-    CRYPTO_atomic_add(&s->references, -1, &i, s->lock);
+    CRYPTO_DOWN_REF(&s->references, &i, s->lock);
     REF_PRINT_COUNT("SSL", s);
     if (i > 0)
         return;
@@ -1379,7 +1379,7 @@
             return 0;
     }
 
-    CRYPTO_atomic_add(&f->cert->references, 1, &i, f->cert->lock);
+    CRYPTO_UP_REF(&f->cert->references, &i, f->cert->lock);
     ssl_cert_free(t->cert);
     t->cert = f->cert;
     if (!SSL_set_session_id_context(t, f->sid_ctx, (int)f->sid_ctx_length)) {
@@ -2570,7 +2570,7 @@
 {
     int i;
 
-    if (CRYPTO_atomic_add(&ctx->references, 1, &i, ctx->lock) <= 0)
+    if (CRYPTO_UP_REF(&ctx->references, &i, ctx->lock) <= 0)
         return 0;
 
     REF_PRINT_COUNT("SSL_CTX", ctx);
@@ -2585,7 +2585,7 @@
     if (a == NULL)
         return;
 
-    CRYPTO_atomic_add(&a->references, -1, &i, a->lock);
+    CRYPTO_DOWN_REF(&a->references, &i, a->lock);
     REF_PRINT_COUNT("SSL_CTX", a);
     if (i > 0)
         return;
@@ -3199,7 +3199,7 @@
 
     /* If we're not quiescent, just up_ref! */
     if (!SSL_in_init(s) || !SSL_in_before(s)) {
-        CRYPTO_atomic_add(&s->references, 1, &i, s->lock);
+        CRYPTO_UP_REF(&s->references, &i, s->lock);
         return s;
     }
 

ssl/ssl_locl.h

diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 88b2f8b..41382ba 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -66,6 +66,7 @@
 # include "statem/statem.h"
 # include "packet_locl.h"
 # include "internal/dane.h"
+# include "internal/refcount.h"
 
 # ifdef OPENSSL_BUILD_SHLIBSSL
 #  undef OPENSSL_EXTERN
@@ -536,7 +537,7 @@
      * certificate is not ok, we must remember the error for session reuse:
      */
     long verify_result;         /* only for servers */
-    int references;
+    CRYPTO_REF_COUNT references;
     long timeout;
     long time;
     unsigned int compress_meth; /* Need to lookup the method */
@@ -663,7 +664,7 @@
                                  * :-) */
     } stats;
 
-    int references;
+    CRYPTO_REF_COUNT references;
 
     /* if defined, these override the X509_verify_cert() calls */
     int (*app_verify_callback) (X509_STORE_CTX *, void *);
@@ -1006,7 +1007,7 @@
     CRYPTO_EX_DATA ex_data;
     /* for server side, keep the list of CA_dn we can use */
     STACK_OF(X509_NAME) *client_CA;
-    int references;
+    CRYPTO_REF_COUNT references;
     /* protocol behaviour */
     uint32_t options;
     /* API behaviour */
@@ -1543,7 +1544,7 @@
     /* If not NULL psk identity hint to use for servers */
     char *psk_identity_hint;
 # endif
-    int references;             /* >1 only if SSL_copy_session_id is used */
+    CRYPTO_REF_COUNT references;             /* >1 only if SSL_copy_session_id is used */
     CRYPTO_RWLOCK *lock;
 } CERT;
 

ssl/ssl_sess.c

diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index 47dbf85..c9a9e23 100644
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -752,7 +752,7 @@
     if (ss == NULL)
         return;
 
-    CRYPTO_atomic_add(&ss->references, -1, &i, ss->lock);
+    CRYPTO_DOWN_REF(&ss->references, &i, ss->lock);
     REF_PRINT_COUNT("SSL_SESSION", ss);
     if (i > 0)
         return;
@@ -788,7 +788,7 @@
 {
     int i;
 
-    if (CRYPTO_atomic_add(&ss->references, 1, &i, ss->lock) <= 0)
+    if (CRYPTO_UP_REF(&ss->references, &i, ss->lock) <= 0)
         return 0;
 
     REF_PRINT_COUNT("SSL_SESSION", ss);