question about ip_build_xmit

[linux lover <linux_lover2004@yahoo.com>]

hello ,
   In ip_output.c file there is ip_build_xmit function
call. when packet comes from tcp layer to IP layer
this function is called. In that i found that 
   skb = sock_alloc_send_skb(sk, length+hh_len+15
,flags&MSG_DONTWAIT, &err);
staement allocates skb for packet. after that i found
that no iphdr adding statement in ip_build_xmit. i
want to know where is iphdr push to skb? cause skb
works using first alloc_skb to allocate memory then
skb_reserve to reserve headroom then put data in skb
by skb_put or skb_push for pushing headers in skb. so
there i found       
  skb->nh.iph = iph = (struct iphdr *)skb_put(skb,
length); 
statement is this does that iphdr adding?

regards,
linuxlover


	
		
__________________________________
Do you Yahoo!?
SBC Yahoo! - Internet access at a great low price.
http://promo.yahoo.com/sbc/