str_ethaddr
(*pr)("ETHER: DST = %s\n", str_ethaddr(eh.ether_dhost));
(*pr)("ETHER: SRC = %s\n", str_ethaddr(eh.ether_shost));
(*pr)("ARP: Ether Src = %s\n", str_ethaddr(esaddr));
(*pr)("ARP: Ether Tgt = %s\n", str_ethaddr(etaddr));
static char *str_ethaddr(const uint8_t *);