Encapsulate access to s->s3->wbuf

Reviewed-by: Richard Levitte <levitte@openssl.org>

ssl/s3_lib.c

diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 2097b79..28eccb4 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3131,7 +3131,7 @@
         return;
 
     ssl3_cleanup_key_block(s);
-    if (s->s3->wbuf.buf != NULL)
+    if (SSL3_BUFFER_is_initialised(RECORD_LAYER_get_wbuf(&s->rlayer)))
         ssl3_release_write_buffer(s);
     if (s->s3->rrec.comp != NULL)
         OPENSSL_free(s->s3->rrec.comp);
@@ -3188,8 +3188,8 @@
 # endif                         /* !OPENSSL_NO_EC */
 #endif                          /* !OPENSSL_NO_TLSEXT */
 
-    wp = s->s3->wbuf.buf;
-    wlen = s->s3->wbuf.len;
+    wp = SSL3_BUFFER_get_buf(RECORD_LAYER_get_wbuf(&s->rlayer));
+    wlen = SSL3_BUFFER_get_len(RECORD_LAYER_get_wbuf(&s->rlayer));
     init_extra = s->s3->init_extra;
     BIO_free(s->s3->handshake_buffer);
     s->s3->handshake_buffer = NULL;
@@ -3203,8 +3203,8 @@
     }
 #endif
     memset(s->s3, 0, sizeof *s->s3);
-    s->s3->wbuf.buf = wp;
-    s->s3->wbuf.len = wlen;
+    SSL3_BUFFER_set_buf(RECORD_LAYER_get_wbuf(&s->rlayer), wp);
+    SSL3_BUFFER_set_len(RECORD_LAYER_get_wbuf(&s->rlayer), wlen);
     s->s3->init_extra = init_extra;
 
     ssl_free_wbio_buffer(s);
@@ -4488,8 +4488,9 @@
     int ret = 0;
 
     if (s->s3->renegotiate) {
-        if ((SSL3_BUFFER_get_left(RECORD_LAYER_get_rbuf(&s->rlayer)) == 0) &&
-            (s->s3->wbuf.left == 0) && !SSL_in_init(s)) {
+        if ((SSL3_BUFFER_get_left(RECORD_LAYER_get_rbuf(&s->rlayer)) == 0)
+            && (SSL3_BUFFER_get_left(RECORD_LAYER_get_wbuf(&s->rlayer)) == 0)
+            && !SSL_in_init(s)) {
             /*
              * if we are the server, and we have sent a 'RENEGOTIATE'
              * message, we need to go to SSL_ST_ACCEPT.