On Wednesday 17 October 2012 13:38:30 Linus Lüssing wrote:
So far the crc16 checksum for a batman-adv broadcast data packet, received on a batman-adv hard interface, was calculated over zero bytes of its content leading to many incoming broadcast data packets wrongly being dropped.
This patch fixes this issue by calculating the crc16 over the actual, complete broadcast payload.
The issue is a regrission introduced by e5cf86d30a9b32feccb6b866a3f23b0e0483a3b0.
Signed-off-by: Linus Lüssing linus.luessing@web.de
It led to about 60-80% broadcast packet loss to a direct neighbor with a ping6 with a 1s interval in our scenario, but about no packet loss with an interval smaller than 0.2s.
Also see: https://projects.universe-factory.net/issues/65 (German)
bridge_loop_avoidance.c | 8 ++++---- routing.c | 8 +++++++- 2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/bridge_loop_avoidance.c b/bridge_loop_avoidance.c index 6705d35..e7b5777 100644 --- a/bridge_loop_avoidance.c +++ b/bridge_loop_avoidance.c @@ -1205,8 +1205,8 @@ int batadv_bla_init(struct batadv_priv *bat_priv) /**
- batadv_bla_check_bcast_duplist
- @bat_priv: the bat priv with all the soft interface information
- @bcast_packet: originator mac address
- @hdr_size: maximum length of the frame
- @bcast_packet: encapsulated broadcast frame plus batman header
- @bcast_packet_len: length of encapsulated broadcast frame plus batman
header *
- check if it is on our broadcast list. Another gateway might
- have sent the same packet because it is connected to the same backbone,
@@ -1219,14 +1219,14 @@ int batadv_bla_init(struct batadv_priv *bat_priv) */ int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, struct batadv_bcast_packet *bcast_packet,
int hdr_size)
int bcast_packet_len){ int i, length, curr; uint8_t *content; uint16_t crc; struct batadv_bcast_duplist_entry *entry;
- length = hdr_size - sizeof(*bcast_packet);
- length = bcast_packet_len - sizeof(*bcast_packet); content = (uint8_t *)bcast_packet; content += sizeof(*bcast_packet);
diff --git a/routing.c b/routing.c index bc2b88b..f861b7c 100644 --- a/routing.c +++ b/routing.c @@ -1136,8 +1136,14 @@ int batadv_recv_bcast_packet(struct sk_buff *skb,
spin_unlock_bh(&orig_node->bcast_seqno_lock);
- /* keep skb linear for crc calculation */
- if (skb_linearize(skb) < 0)
goto out;
Please don't ues linearize here. Try to fix the crc calculation using skb_walk_frags (see for example net/netfilter/nf_nat_proto_sctp.c ).
And Simon owes you a beer for this debugging ;)
Kind regards, Sven