batman-adv: Fix endianness errors for network coding

Add a htonl() in network_coding.c when reading the sequence number
from received ogm_packet, to avoid wrong byte ordering when comparing
with a host value. This bug was introduced in
3ed7ada3f0bbcd058567bc0a8f9729a73eba7db6 ("batman-adv: network coding -
detect coding nodes and remove these after timeout").

Change the type of coded_packet->coded_len from uint16 to __be16 to
avoid wrong assumptions about endianness in later uses. Introduced in
c3289f3650d34b60296000a629c99f2488f7c3dd ("batman-adv: network coding -
code and transmit packets if possible").

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

net/batman-adv/network-coding.c

@@ -654,7 +654,7 @@ static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
 				    struct batadv_orig_node *orig_node,
 				    struct batadv_ogm_packet *ogm_packet)
 {
-	if (orig_node->last_real_seqno != ogm_packet->seqno)
+	if (orig_node->last_real_seqno != ntohl(ogm_packet->seqno))
 		return false;
 	if (orig_node->last_ttl != ogm_packet->header.ttl + 1)
 		return false;

net/batman-adv/packet.h

@@ -308,7 +308,7 @@ struct batadv_coded_packet {
 	uint8_t  second_source[ETH_ALEN];
 	uint8_t  second_orig_dest[ETH_ALEN];
 	__be32   second_crc;
-	uint16_t coded_len;
+	__be16   coded_len;
 };
 
 #endif /* _NET_BATMAN_ADV_PACKET_H_ */