/* icmp.h - definintions for the Internet Control Message Protocol */

#define ICMP_SLOTS      10              /* Num. of open ICMP endpoints  */
#define ICMP_QSIZ       8               /* Incoming packets per slot    */

/* Constants for the state of an entry */

#define ICMP_FREE       0               /* Entry is unused              */
#define ICMP_USED       1               /* Entry is being used          */
#define ICMP_RECV       2               /* Entry has a process waiting  */

#define ICMP_HDR_LEN    8               /* Bytes in an ICMP header      */

/* ICMP message types for ping */

#define ICMP_ECHOREPLY  0               /* ICMP Echo Reply message      */
#define ICMP_ECHOREQST  8               /* ICMP Echo Request message    */

/* Table of processes that are waiting for ping replies */

struct  icmpentry {                     /* Entry in the ICMP table      */
        int32   icstate;                /* State of entry: free/used    */
        uint32  icremip;                /* Remote IP address            */
        int32   ichead;                 /* Index of next packet to read */
        int32   ictail;                 /* Index of next slot to insert */
        int32   iccount;                /* Count of packets enqueued    */
        pid32   icpid;                  /* ID of waiting process        */
        struct  netpacket *icqueue[ICMP_QSIZ];/* Circular packet queue  */
};

extern  struct  icmpentry icmptab[];    /* Table of UDP endpoints       */