Let's start with net/batman-adv/translation-table.c:send_tt_request(). Its tt_crc argument gets stored into skb as-is and skb goes on the wire. OK, so it's fixed-endian, right?
That sucker comes straight from the (only) caller - tt_update_orig(). There it gets compared with ->tt_crc of struct orig_node instances. Fine, except that just prior to that comparison we assign to ->tt_crc the return value of tt_global_crc(). Which is built on crc16_byte() and clearly returns a host-endian value. Additionally, orig_node ->tt_crc is getting compared to tt_request->tt_data in send_other_tt_response(), which ultimately comes from recv_tt_query() where it's flipped from net-endian to host-endian.
It gets even funnier - we have 3 structures with ->tt_crc in them; one is struct orig_node (see above), another is struct batman_ogv_packet and then there's the weirdest one - struct bat_priv. Where ->tt_crc is atomic_t, of all things. With exactly two things ever done to it: batman_ogm_packet->tt_crc = htons((uint16_t) atomic_read(&bat_priv->tt_crc)); in bat_iv_ogm_schedule() and atomic_set(&bat_priv->tt_crc, tt_local_crc(bat_priv)); in prepare_packet_buffer(). What the hell does that have to do with atomic_t? At least that one is definitely host-endian all along (tt_local_crc() is the same kind of built-on-crc16_byte() thing).
And then there's batman_ogv_packet, where we flip the damn field from net-endian to host-endian and back. That's where the argument of tt_update_orig() comes from, AFAICS always in host-endian form.
IOW, unless I'm misreading that code we have bat_priv ->tt_crc: host-endian, no need to make it atomic_t orig_node ->tt_crc: host-endian tt_update_orig()/send_tt_request() tt_crc argument: host-endian the value put into the packet in send_tt_request(): broken; should be net-endian, in reality it's host-endian. Missing htons() at the very least.
Could somebody familiar with that code comment on that?