The following commit has been merged in the master branch: commit 5c77d8bb8aeb4ec6804b6c32061109ba2ea6988d Author: Sven Eckelmann firstname.lastname@example.org Date: Tue Jan 25 21:59:26 2011 +0000
batman-adv: Create roughly equal sized fragments
The routing algorithm must know how large two fragments are to be able to decide that it is safe to merge them or if it should resubmit without waiting for the second part. When these two fragments have a too different size, it is not possible to guess right in every situation.
The user could easily configure the MTU of the attached cards so that one fragment is forwarded and the other one is added to the fragments table to wait for the missing part.
For even sized packets, it is possible to split it so that the resulting packages are equal sized by ignoring the old non-fragment header at the beginning of the original packet.
This still creates different sized fragments for uneven sized packets.
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c index ee41fef..811f7fc 100644 --- a/net/batman-adv/unicast.c +++ b/net/batman-adv/unicast.c @@ -224,7 +224,7 @@ int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, struct unicast_frag_packet *frag1, *frag2; int uc_hdr_len = sizeof(struct unicast_packet); int ucf_hdr_len = sizeof(struct unicast_frag_packet); - int data_len = skb->len; + int data_len = skb->len - uc_hdr_len;
if (!bat_priv->primary_if) goto dropped; @@ -232,10 +232,11 @@ int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len); if (!frag_skb) goto dropped; + skb_reserve(frag_skb, ucf_hdr_len);
unicast_packet = (struct unicast_packet *) skb->data; memcpy(&tmp_uc, unicast_packet, uc_hdr_len); - skb_split(skb, frag_skb, data_len / 2); + skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 || my_skb_head_push(frag_skb, ucf_hdr_len) < 0)