Re: [B.A.T.M.A.N.] [PATCH 3/6] batman-adv: register batman ogm receive function during protocol init

[Marek Lindner]

On Sunday, March 04, 2012 01:59:53 Simon Wunderlich wrote:
 On Thu, Mar 01, 2012 at 03:35:18PM +0800, Marek Lindner wrote:
  -static void bat_iv_ogm_receive(struct hard_iface *if_incoming,
  -  struct sk_buff *skb)
  +static void _bat_iv_ogm_receive(struct sk_buff *skb,
  +   struct hard_iface *if_incoming)
 
 rant
 Personally, I don't like underscore functions. They are usually created
 because of a lack of creativity, but are later called from different
 places, do different jobs and in the end everyone is confused. :) Is it
 possibble to change the name, e.g. to bat_iv_ogm_handle()?
 /rant

Hmm.., I kind of agree. I'll think about another solution.  :-)


 We should somewhere add a check whether the hard_iface is actually assigned
 to a mesh using the BATMAN IV algorithm. When more algorithms are added,
 we only want the assigned protocol to be handled, others should be
 ignored.

You are right - we need a check but not necessarily in this patch. We lived 
without such a check for quite while. This patch is not introducing a loophole 
that did not exist before. I'll send a separate patch.

Thanks for the comments!

Cheers,
Marek

Re: [B.A.T.M.A.N.] [PATCH 3/6] batman-adv: register batman ogm receive function during protocol init

[Simon Wunderlich]

On Thu, Mar 01, 2012 at 03:35:18PM +0800, Marek Lindner wrote:
 -static void bat_iv_ogm_receive(struct hard_iface *if_incoming,
 -struct sk_buff *skb)
 +static void _bat_iv_ogm_receive(struct sk_buff *skb,
 + struct hard_iface *if_incoming)

rant
Personally, I don't like underscore functions. They are usually created
because of a lack of creativity, but are later called from different places,
do different jobs and in the end everyone is confused. :) Is it possibble to
change the name, e.g. to bat_iv_ogm_handle()?
/rant


  {
   struct batman_ogm_packet *batman_ogm_packet;
   struct ethhdr *ethhdr;
 @@ -1200,6 +1200,39 @@ static void bat_iv_ogm_receive(struct hard_iface 
 *if_incoming,
   batman_ogm_packet-tt_num_changes));
  }
  
 +static int bat_iv_ogm_receive(struct sk_buff *skb,
 +   struct hard_iface *hard_iface)
 +{
 + struct ethhdr *ethhdr;
 +
 + /* drop packet if it has not necessary minimum size */
 + if (unlikely(!pskb_may_pull(skb, BATMAN_OGM_HLEN)))
 + return NET_RX_DROP;
 +
 + ethhdr = (struct ethhdr *)skb_mac_header(skb);
 +
 + /* packet with broadcast indication but unicast recipient */
 + if (!is_broadcast_ether_addr(ethhdr-h_dest))
 + return NET_RX_DROP;
 +
 + /* packet with broadcast sender address */
 + if (is_broadcast_ether_addr(ethhdr-h_source))
 + return NET_RX_DROP;
 +
 + /* create a copy of the skb, if needed, to modify it. */
 + if (skb_cow(skb, 0)  0)
 + return NET_RX_DROP;
 +
 + /* keep skb linear */
 + if (skb_linearize(skb)  0)
 + return NET_RX_DROP;
 +
 + _bat_iv_ogm_receive(skb, hard_iface);
 +
 + kfree_skb(skb);
 + return NET_RX_SUCCESS;
 +}
 +

We should somewhere add a check whether the hard_iface is actually assigned to
a mesh using the BATMAN IV algorithm. When more algorithms are added, we only 
want
the assigned protocol to be handled, others should be ignored.

Cheers,
Simon


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