tool: show if server sent OCSP staple

Change-Id: Ib9df4e8f797c9af3362354cc6716171fd65600de
Reviewed-on: https://boringssl-review.googlesource.com/12720
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

tool/transport_common.cc

@@ -272,6 +272,13 @@ void PrintConnectionInfo(const SSL *ssl) {
     fprintf(stderr, "  Client sent SNI: %s\n", host_name);
   }
 
+  if (!SSL_is_server(ssl)) {
+    const uint8_t *ocsp_staple;
+    size_t ocsp_staple_len;
+    SSL_get0_ocsp_response(ssl, &ocsp_staple, &ocsp_staple_len);
+    fprintf(stderr, "  OCSP staple: %s\n", ocsp_staple_len > 0 ? "yes" : "no");
+  }
+
   // Print the server cert subject and issuer names.
   bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(ssl));
   if (peer != nullptr) {