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/*
* arp.h
*
* Address Resolution Protocol.
* RFC 826
*
* Copyright (c) 2000 Dug Song <dugsong@monkey.org>
*
* $Id: arp.h,v 1.12 2003/03/16 17:39:17 dugsong Exp $
*/
#ifndef DNET_ARP_H
#define DNET_ARP_H
#define ARP_HDR_LEN 8 /* base ARP header length */
#define ARP_ETHIP_LEN 20 /* base ARP message length */
#ifndef __GNUC__
# define __attribute__(x)
# pragma pack(1)
#endif
/*
* ARP header
*/
struct arp_hdr {
uint16_t ar_hrd; /* format of hardware address */
uint16_t ar_pro; /* format of protocol address */
uint8_t ar_hln; /* length of hardware address (ETH_ADDR_LEN) */
uint8_t ar_pln; /* length of protocol address (IP_ADDR_LEN) */
uint16_t ar_op; /* operation */
};
/*
* Hardware address format
*/
#define ARP_HRD_ETH 0x0001 /* ethernet hardware */
#define ARP_HRD_IEEE802 0x0006 /* IEEE 802 hardware */
/*
* Protocol address format
*/
#define ARP_PRO_IP 0x0800 /* IP protocol */
/*
* ARP operation
*/
#define ARP_OP_REQUEST 1 /* request to resolve ha given pa */
#define ARP_OP_REPLY 2 /* response giving hardware address */
#define ARP_OP_REVREQUEST 3 /* request to resolve pa given ha */
#define ARP_OP_REVREPLY 4 /* response giving protocol address */
/*
* Ethernet/IP ARP message
*/
struct arp_ethip {
uint8_t ar_sha[ETH_ADDR_LEN]; /* sender hardware address */
uint8_t ar_spa[IP_ADDR_LEN]; /* sender protocol address */
uint8_t ar_tha[ETH_ADDR_LEN]; /* target hardware address */
uint8_t ar_tpa[IP_ADDR_LEN]; /* target protocol address */
};
/*
* ARP cache entry
*/
struct arp_entry {
struct addr arp_pa; /* protocol address */
struct addr arp_ha; /* hardware address */
};
#ifndef __GNUC__
# pragma pack()
#endif
#define arp_pack_hdr_ethip(hdr, op, sha, spa, tha, tpa) do { \
struct arp_hdr *pack_arp_p = (struct arp_hdr *)(hdr); \
struct arp_ethip *pack_ethip_p = (struct arp_ethip *) \
((uint8_t *)(hdr) + ARP_HDR_LEN); \
pack_arp_p->ar_hrd = htons(ARP_HRD_ETH); \
pack_arp_p->ar_pro = htons(ARP_PRO_IP); \
pack_arp_p->ar_hln = ETH_ADDR_LEN; \
pack_arp_p->ar_pln = IP_ADDR_LEN; \
pack_arp_p->ar_op = htons(op); \
memmove(pack_ethip_p->ar_sha, &(sha), ETH_ADDR_LEN); \
memmove(pack_ethip_p->ar_spa, &(spa), IP_ADDR_LEN); \
memmove(pack_ethip_p->ar_tha, &(tha), ETH_ADDR_LEN); \
memmove(pack_ethip_p->ar_tpa, &(tpa), IP_ADDR_LEN); \
} while (0)
typedef struct arp_handle arp_t;
typedef int (*arp_handler)(const struct arp_entry *entry, void *arg);
__BEGIN_DECLS
arp_t *arp_open(void);
int arp_add(arp_t *arp, const struct arp_entry *entry);
int arp_delete(arp_t *arp, const struct arp_entry *entry);
int arp_get(arp_t *arp, struct arp_entry *entry);
int arp_loop(arp_t *arp, arp_handler callback, void *arg);
arp_t *arp_close(arp_t *arp);
__END_DECLS
#endif /* DNET_ARP_H */