Hi³, :)
On Mon, May 13, 2013 at 10:23:02PM +0200, Martin Hundebøll wrote:
[..]
+/**
- batadv_frag_create - create a fragment from skb.
- @skb: skb to create fragment from.
- @frag_head: header to use in new fragment.
- @mtu: Size of new fragment.
- Split the passed skb into two fragments: A new one with size matching the
- passed mtu and the old one with the rest. The new skb contains data from the
- tail of the old skb.
- Returns the new fragment, NULL on error.
- */
+static struct sk_buff *batadv_frag_create(struct sk_buff *skb,
struct batadv_frag_packet *frag_head,unsigned int mtu)+{
- struct sk_buff *skb_fragment;
- unsigned header_size = sizeof(*frag_head);
- unsigned fragment_size = mtu - header_size - ETH_HLEN;
- skb_fragment = dev_alloc_skb(mtu);
If I am not wrong, the external Ethernet header is not counted in the MTU of an interface. Therefore if the MTU of eth0 is X, it should mean that eth0 will send a packet of 1500 of payload + the external Ethernet encapsulation. isn't it?
- if (!skb_fragment)
goto err;- /* Eat the last mtu-bytes of the skb */
- skb_reserve(skb_fragment, header_size);
why not reserving header_size + ETH_HLEN (ETH_HLEN would be the space for the external Ethernet header).
- skb_split(skb, skb_fragment, skb->len - fragment_size);
- /* Add the header */
- skb_push(skb_fragment, header_size);
- memcpy(skb_fragment->data, frag_head, header_size);
+err:
- return skb_fragment;
+}
[...]
@@ -110,7 +109,19 @@ int batadv_send_skb_to_orig(struct sk_buff *skb, /* batadv_find_router() increases neigh_nodes refcount if found. */ neigh_node = batadv_find_router(bat_priv, orig_node, recv_if); if (!neigh_node)
return ret;
goto out;- /* Check if the skb is too large to send in one piece and fragment
* it if needed.*/- if (atomic_read(&bat_priv->fragmentation) &&
skb->len + ETH_HLEN > neigh_node->if_incoming->net_dev->mtu) {
same as before: the external Ethernet header should not be taken into consideration while checking the MTU (no?).
My suggestion is to do:
"skb->len > neigh_node->if_incoming->net_dev->mtu) {"
/* Fragment and send packet. */if (batadv_frag_send_packet(skb, orig_node, neigh_node))ret = NET_XMIT_SUCCESS;goto out;}
/* try to network code the packet, if it is received on an interface
- (i.e. being forwarded). If the packet originates from this node or if
Thank you for your work Martin! :)
Cheers,