Re: [B.A.T.M.A.N.] [PATCHv3 1/2] batman-adv: Check total_size when queueing fragments

Hi,

On 2014-12-01 10:37, Sven Eckelmann wrote:

The fragmentation code was replaced in 9b3eab61754d74a93c9840c296013fe3b4a1b606 ("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

This is only compile tested

v3.

• withdrawing from inclusion in maint
• remove wrong example from the commit message

v2:

• proposed for maint
• changed commit message slightly

---

fragmentation.c | 7 +++++-- types.h | 2 ++ 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fragmentation.c b/fragmentation.c index 5251aa1..6e4c957 100644 --- a/fragmentation.c +++ b/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/types.h b/types.h index 462a70c..c4d7d24 100644 --- a/types.h +++ b/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; };

  /**

As with the first version: Acked-by: Martin Hundebøll martin@hundeboll.net