/* arp.h */

/* Items related to ARP - definition of cache and the packet format */

#define ARP_HALEN       6               /* Size of Ethernet MAC address */
#define ARP_PALEN       4               /* Size of IP address           */

#define ARP_HTYPE       1               /* Ethernet hardware type       */
#define ARP_PTYPE       0x0800          /* IP protocol type             */

#define ARP_OP_REQ      1               /* Request op code              */
#define ARP_OP_RPLY     2               /* Reply op code                */

#define ARP_SIZ         16              /* Number of entries in a cache */

#define ARP_RETRY       3               /* Num. retries for ARP request */

#define ARP_TIMEOUT     300             /* Retry timer in milliseconds  */

/* State of an ARP cache entry */

#define AR_FREE         0               /* Slot is unused               */
#define AR_PENDING      1               /* Resolution in progress       */
#define AR_RESOLVED     2               /* Entry is valid               */

#pragma pack(2)
struct  arppacket {                     /* ARP packet for IP & Ethernet */
        byte    arp_ethdst[ETH_ADDR_LEN];/* Ethernet dest. MAC addr     */
        byte    arp_ethsrc[ETH_ADDR_LEN];/* Ethernet source MAC address */
        uint16  arp_ethtype;            /* Ethernet type field          */
        uint16  arp_htype;              /* ARP hardware type            */
        uint16  arp_ptype;              /* ARP protocol type            */
        byte    arp_hlen;               /* ARP hardware address length  */
        byte    arp_plen;               /* ARP protocol address length  */
        uint16  arp_op;                 /* ARP operation                */
        byte    arp_sndha[ARP_HALEN];   /* ARP sender's Ethernet addr   */
        uint32  arp_sndpa;              /* ARP sender's IP address      */
        byte    arp_tarha[ARP_HALEN];   /* ARP target's Ethernet addr   */
        uint32  arp_tarpa;              /* ARP target's IP address      */
};
#pragma pack()

struct  arpentry {                      /* Entry in the ARP cache       */
        int32   arstate;                /* State of the entry           */
        uint32  arpaddr;                /* IP address of the entry      */
        pid32   arpid;                  /* Waiting process or -1        */
        byte    arhaddr[ARP_HALEN];     /* Ethernet address of the entry*/
};

extern struct   arpentry arpcache[];