how to use kernel macro funcions in bpftrace?

Question

how to use kernel macro funcions in bpftrace, like ip_hdr.

I have write below code:

#include <linux/ip.h>

kprobe:icmp_echo
{
    $skb = (struct sk_buff *)arg0;
    $iph = (struct iphdr *)ip_hdr($skb);
    printf("sip:%x", $iph->saddr);
    printf("dip:%x", $iph->daddr);
}

'ip_hdr' is a macro function, defined in ip.h, but encounter an error:

bpftrace icmp1.bt
icmp1.bt:6:12-35: ERROR: Unknown function: ip_hdr
    $iph = (struct iphdr *)ip_hdr($skb);

Does anyone know why? Thanks.