cipher_set_counter(&s->incipher, &seqno, sizeof seqno);
if(!cipher_counter_xor(&s->incipher, buffer + 6, len - 4, buffer + 6))
return false;
cipher_set_counter(&s->incipher, &seqno, sizeof seqno);
if(!cipher_counter_xor(&s->incipher, buffer + 6, len - 4, buffer + 6))
return false;