icmp.h

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/* 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   */