I want to access packet stored skb before it gets dequeued from cbq
scheduler. I want to do this from within cbq_update(){} having the pointer
to cbq_sched_data *q.
The cbq_class declared in sch_cbq.c has two pointers to Qdisc queueing
discipline (q, qdisc). From the description in sch_cbq.c I see that:
struct cbq_class{
[..]
124 struct Qdisc *qdisc; /* Ptr to CBQ discipline*/
133 struct Qdisc *q; /* Elementary queueing discipline */
[..]
}
So to access packet (skb) in the queue I do:
cbq_class *cl = q->tx_class; // access current tx class
list = ((struct sk_buff_head*)cl->q->data); //get the pointer to
the list hosting our packet
_prev = (struct sk_buff*) list; // try to reach skb that waits in the queue
_next = _prec->next; // access skb that is first in current class qdisc
// I found that sk_buff_head's next points to the
// first packet in the queue
If(_prev != _next) _skb = _next;
/*now the critical one */
printk("skb.len= %d \n",_skb->len); THIS LINE GENERATES OOPS whatever skb
struct field I try to access!!!
(the code above is based mainly on pfifo_fast_dequeue(){})
Can anyone pls point what I do wrong?
Thank you in advance.
Adam
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