[PATCH 1/5] batman-adv: Limit number of aggregated packets directly

[Sven Eckelmann <sven@narfation.org>]

The currently selected size in BATADV_MAX_AGGREGATION_BYTES (512) is chosen
such that the number of possible aggregated packets is lower than 32. This
number must be limited so that the type of
batadv_forw_packet->direct_link_flags has enough bits to represent each
packet (with the size of at least 24 bytes).

This requirement is better implemented in code instead of having it inside
a comment.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/bat_iv_ogm.c | 4 ++++
 net/batman-adv/main.h       | 3 ---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 07ae5dd1f150b062e97897b269d45b041e8b4dfe..b316cfc5b8769928a77ac936e5935ae780d5ad68 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -446,6 +446,7 @@ batadv_iv_ogm_can_aggregate(const struct batadv_ogm_packet *new_bat_ogm_packet,
 	struct batadv_ogm_packet *batadv_ogm_packet;
 	int aggregated_bytes = forw_packet->packet_len + packet_len;
 	struct batadv_hard_iface *primary_if = NULL;
+	u8 packet_num = forw_packet->num_packets + 1;
 	bool res = false;
 	unsigned long aggregation_end_time;
 
@@ -468,6 +469,9 @@ batadv_iv_ogm_can_aggregate(const struct batadv_ogm_packet *new_bat_ogm_packet,
 	if (aggregated_bytes > BATADV_MAX_AGGREGATION_BYTES)
 		return false;
 
+	if (packet_num >= BITS_PER_TYPE(forw_packet->direct_link_flags))
+		return false;
+
 	/* packet is not leaving on the same interface. */
 	if (forw_packet->if_outgoing != if_outgoing)
 		return false;
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 964f3088af5b52d3ad1d709fb964dc2c3d79d7a5..485e68a06835b48923278da7b9aa79db6968945f 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -102,9 +102,6 @@
  */
 #define BATADV_TQ_SIMILARITY_THRESHOLD 50
 
-/* should not be bigger than 512 bytes or change the size of
- * forw_packet->direct_link_flags
- */
 #define BATADV_MAX_AGGREGATION_BYTES 512
 #define BATADV_MAX_AGGREGATION_MS 100
 

-- 
2.47.2