From: Sven Eckelmann sven@narfation.org
The fragmentation code was replaced in 610bfc6bc99bc83680d190ebc69359a05fc7f605 ("batman-adv: Receive fragmented packets and merge") by an implementation which handles the queueing+merging of fragments based on their size and the total_size of the non-fragmented packet. This total_size is announced by each fragment. The new implementation doesn't check if the the total_size information of the packets inside one chain is consistent.
This is consistency check is recommended to allow using any of the packets in the queue to decide whether all fragments of a packet are received or not.
Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Martin Hundebøll martin@hundeboll.net Signed-off-by: Marek Lindner mareklindner@neomailbox.ch Signed-off-by: Antonio Quartulli antonio@meshcoding.com --- net/batman-adv/fragmentation.c | 7 +++++-- net/batman-adv/types.h | 2 ++ 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index af495cc..a9fc653 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -161,6 +161,7 @@ static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node, hlist_add_head(&frag_entry_new->list, &chain->head); chain->size = skb->len - hdr_size; chain->timestamp = jiffies; + chain->total_size = ntohs(frag_packet->total_size); ret = true; goto out; } @@ -195,9 +196,11 @@ static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node,
out: if (chain->size > batadv_frag_size_limit() || - ntohs(frag_packet->total_size) > batadv_frag_size_limit()) { + chain->total_size != ntohs(frag_packet->total_size) || + chain->total_size > batadv_frag_size_limit()) { /* Clear chain if total size of either the list or the packet - * exceeds the maximum size of one merged packet. + * exceeds the maximum size of one merged packet. Don't allow + * packets to have different total_size. */ batadv_frag_clear_chain(&chain->head); chain->size = 0; diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 28f2461..e95db42 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -132,6 +132,7 @@ struct batadv_orig_ifinfo { * @timestamp: time (jiffie) of last received fragment * @seqno: sequence number of the fragments in the list * @size: accumulated size of packets in list + * @total_size: expected size of the assembled packet */ struct batadv_frag_table_entry { struct hlist_head head; @@ -139,6 +140,7 @@ struct batadv_frag_table_entry { unsigned long timestamp; uint16_t seqno; uint16_t size; + uint16_t total_size; };
/**