KEX_COOKIE_LEN
for (i = 0; i < KEX_COOKIE_LEN; i++) {
if ((r = sshbuf_consume(b, KEX_COOKIE_LEN)) != 0) { /* skip cookie */
if (sshbuf_len(kex->my) < KEX_COOKIE_LEN) {
sshbuf_len(kex->my), KEX_COOKIE_LEN);
arc4random_buf(cookie, KEX_COOKIE_LEN);
for (i = 0; i < KEX_COOKIE_LEN; i++) {