/**
 * struct arpmsg - 802.2 ARP IPv4 payload
 * @sha:	Sender hardware address
 * @sip:	Sender IP address
 * @tha:	Target hardware address
 * @tip:	Target IP address
 */
struct arpmsg {
	unsigned char sha[ETH_ALEN];
	unsigned char sip[4];
	unsigned char tha[ETH_ALEN];
	unsigned char tip[4];
} __attribute__((__packed__));

int arp(struct ctx *c, struct ethhdr *eh, size_t len);