+ if (cc->use_sideband) {
+ ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
+ buf = NULL;
+ if (ret < 0)
+ goto net_err;
+ buf = para_malloc(HANDSHAKE_BUFSIZE);
+ } else {
+ ret = write_all(fd, buf, numbytes);
+ if (ret < 0)
+ goto net_err;
+ }