are u doin some sort of tunneling ?

On Fri, Apr 6, 2012 at 6:03 AM, Sri Ram Vemulpali
[off-list ref]wrote:

Whenever you manipulate the packet before PRE_ROUTING point in the
stack, the kernel will decide whether to route the packet to LOCAL or
FORWARD. If you have pointer pointing to right IP header kernel will
use it to route. You really do not have to write routing code.

Also, when you say inner and outer header what do you mean by it. I
did not encounter this.

Thanks,
Sri.

On Thu, Apr 5, 2012 at 5:00 AM, SaNtosh kuLkarni
[off-list ref] wrote:

quoted

i had a similar problem where in i was using SKB_PUSH to add extra
header,,,, i used this... structure called flowi.... which can be used to
define a sort of traffic class...based on some combination of fields


iph->daddr =htonl(xxxxxx);
{
struct rtable *rt;
struct flowi fl;
memset(&fl, 0x0, sizeof(struct flowi));
fl.fl4_dst  = htonl(xxxxxxx);
fl.proto = IPPROTO_TCP;
if (!ip_route_output_key(&init_net, &rt, &fl))
{
iph->saddr= htonl(ntohl(rt->rt_src));

skb_dst_set(skb2, &rt->u.dst);

}

}


On Mon, Apr 2, 2012 at 2:12 PM, Kesava Srinivas <vunnavafuture@gmail.com

wrote:

quoted

HI Friends,
Looking for a Confirmation on my analysis.

Once after Capturing the Socket Buffer in PRE_ROUTING Hook; Manipulated
the Socket Buffer by using the "skb_pull" Kernel Function. Using

skb_pull;

quoted

quoted

stripped 28 bytes (IP+UDP) which are the Part of outer UDP/IP Header.

Now;

quoted

quoted

My intention was to route the skb based on the Inner IP Header which is
sitting after stripping 28 bytes. At the END; returned NF_ACCEPT.

Even though; skb_pull worked Fine., Kernel's Stack is still looking in

to

quoted

quoted

Outer Header only for Routing the Packet.I expected ;Kernel will look

the

quoted

quoted

Inner Header (As data Pointer was incremented by 28 bytes via skb_pull)

and

quoted

quoted

Take decision based on the Inner one. But; that didn't  happened. It

looks

quoted

quoted

to me like; we need to always use NF_STOLEN & should write our own code

to

quoted

quoted

route based on the INNER HEADER. Was my conclusion correct ??

-Thanks in Advance,
VKS



_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

--
Regards,
Sri.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120406/0b40cac7/attachment.html