[Aodvimpl] How to modify kaodv-ipenc.c to port aodv-uu 0.9.5 to Linux kernel 2.6.26?

[Wang R. <wan...@ue...>]

Hi,

         I am trying to port aodv-uu 0.9.5 to Linux kernel 2.6.26. The
netfilter implementation has changed since 2.6.24 : 

 

    [NETFILTER]: Replace sk_buff ** with sk_buff *

    

    With all the users of the double pointers removed, this patch mops up by

    finally replacing all occurances of sk_buff ** in the netfilter API by

sk_buff *.

 

So the original 0.9.5 implementation of struct sk_buff
*ip_pkt_encapsulate(struct sk_buff *skb, __u32 dest) no longer works. I
tried to modify ip_pkt_encapsulate by using pskb_expand_head instead of
skb_copy_expand:

struct sk_buff *ip_pkt_encapsulate(struct sk_buff *skb, __u32 dest)

{

    int oldlen;

 

    struct min_ipenc_hdr *ipe;    

    struct iphdr *iph;

    

    /* Allocate new data space at head */

    if( pskb_expand_head(skb,0,

                   sizeof(struct min_ipenc_hdr),GFP_ATOMIC) < 0) {

                   printk("Could not expand skb header\n");

                   kfree_skb(skb);

                   return NULL;    

    }

 

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22))

    iph = skb->nh.iph;

#else

    iph = (struct iphdr *)skb->network_header;

#endif

    oldlen = skb->len;

         skb_put(skb, sizeof(struct min_ipenc_hdr));

    

    /* Move the data */

    memmove(skb->data + (iph->ihl << 2) + sizeof(struct min_ipenc_hdr), 

            skb->data + (iph->ihl << 2), oldlen - (iph->ihl << 2));

    

    /* Update pointers */

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22))

    iph = skb->nh.iph = (struct iphdr *)skb->data;

#else

    iph = (struct iphdr *)skb->data;

    skb->network_header = skb->data;

#endif

 

    ipe = (struct min_ipenc_hdr *)(skb->data + (iph->ihl << 2));

.

}

 

But the kaodv module crashes when sending paged packages, saying that the
skb is not linear, so I added:

If(!skb_make_writable(skb,skb->len)) {

         printk("Could not make skb writable\n");

         return NULL;

}

just before calling pskb_expand_head. The module stops crashing this time,
but the package still cannot deliver correctly.

Can anybody tell me how to modify ip_pkt_encapsulate to correctly add the
additional header to the paged skb?

 

Wang Rui

wan...@ue..., wan...@gm...