udp.h

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/* udp.h - Declarations pertaining to User Datagram Protocol (UDP) */

#define UDP_SLOTS   6       /* Number of open UDP endpoints */
#define UDP_QSIZ    8       /* Packets enqueued per endpoint*/

#define UDP_DHCP_CPORT  68      /* Port number for DHCP client  */
#define UDP_DHCP_SPORT  67      /* Port number for DHCP server  */

/* Constants for the state of an entry */

#define UDP_FREE    0       /* Entry is unused      */
#define UDP_USED    1       /* Entry is being used      */
#define UDP_RECV    2       /* Entry has a process waiting  */

#define UDP_ANYIF   -2      /* Register an endpoint for any */
                    /*   interface on the machine   */

#define UDP_HDR_LEN 8       /* Bytes in a UDP header    */

struct  udpentry {          /* Entry in the UDP endpoint tbl*/
    int32   udstate;        /* State of entry: free/used    */
    uint32  udremip;        /* Remote IP address (zero  */
                    /*   means "don't care")    */
    uint16  udremport;      /* Remote protocol port number  */
    uint16  udlocport;      /* Local protocol port number   */
    int32   udhead;         /* Index of next packet to read */
    int32   udtail;         /* Index of next slot to insert */
    int32   udcount;        /* Count of packets enqueued    */
    pid32   udpid;          /* ID of waiting process    */
    struct  netpacket *udqueue[UDP_QSIZ];/* Circular packet queue   */
};

extern  struct  udpentry udptab[];