sk_run_filter -- run a filter on a socket
(struct sk_buff * skb, struct sock_filter * filter, int flen);
buffer to run the filter on
filter to apply
length of filter
Decode and apply filter instructions to the skb->data.
Return length to keep, 0 for none. skb is the data we are
filtering, filter is the array of filter instructions, and
len is the number of filter blocks in the array.