sys/netatalk/ddp.h

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/*
 * Copyright (c) 1990,1991 Regents of The University of Michigan.
 * All Rights Reserved. See COPYRIGHT.
 */
 
/*
 * <-1byte(8bits) ->
 * +---------------+
 * | 0 | hopc  |len|
 * +---------------+
 * | len (cont)    |
 * +---------------+
 * |               |
 * +- DDP csum    -+
 * |               |
 * +---------------+
 * |               |
 * +- Dest NET    -+
 * |               |
 * +---------------+
 * |               |
 * +- Src NET     -+
 * |               |
 * +---------------+
 * | Dest NODE     |
 * +---------------+
 * | Src NODE      |
 * +---------------+
 * | Dest PORT     |
 * +---------------+
 * | Src PORT      |
 * +---------------+
 *
 * On Apples, there is also a ddp_type field, after src_port. However,
 * under this unix implementation, user level processes need to be able
 * to set the ddp_type. In later revisions, the ddp_type may only be
 * available in a raw_appletalk interface.
 */
 
#ifndef _NETATALK_DDP_H
#define _NETATALK_DDP_H 1
 
#include "endian.h"
 
struct elaphdr {
    unsigned char   el_dnode;
    unsigned char   el_snode;
    unsigned char   el_type;
};
 
#define SZ_ELAPHDR  3
 
#define ELAP_DDPSHORT   0x01
#define ELAP_DDPEXTEND  0x02
 
/*
 * Extended DDP header. Includes sickness for dealing with arbitrary
 * bitfields on a little-endian arch.
 */
struct ddpehdr {
    union {
        struct {
#if BYTE_ORDER == BIG_ENDIAN
            unsigned        dub_pad: 2;
            unsigned        dub_hops: 4;
            unsigned        dub_len: 10;
            unsigned        dub_sum: 16;
#else /* BYTE_ORDER == BIG_ENDIAN */
#if BYTE_ORDER == LITTLE_ENDIAN
            unsigned        dub_sum: 16;
            unsigned        dub_len: 10;
            unsigned        dub_hops: 4;
            unsigned        dub_pad: 2;
#else /* BYTE_ORDER == LITTLE_ENDIAN */
            OOPS!
#endif /* BYTE_ORDER == LITTLE_ENDIAN */
#endif /* BYTE_ORDER == BIG_ENDIAN */
        } du_bits;
        unsigned    du_bytes;
    } deh_u;
#define deh_pad     deh_u.du_bits.dub_pad
#define deh_hops    deh_u.du_bits.dub_hops
#define deh_len     deh_u.du_bits.dub_len
#define deh_sum     deh_u.du_bits.dub_sum
#define deh_bytes   deh_u.du_bytes
    unsigned short      deh_dnet;
    unsigned short      deh_snet;
    unsigned char       deh_dnode;
    unsigned char       deh_snode;
    unsigned char       deh_dport;
    unsigned char       deh_sport;
};
 
#define SZ_DDPEHDR      12
 
#define DDP_MAXHOPS 15
 
struct ddpshdr {
    union {
        struct {
#if BYTE_ORDER == BIG_ENDIAN
            unsigned        dub_pad: 6;
            unsigned        dub_len: 10;
            unsigned        dub_dport: 8;
            unsigned        dub_sport: 8;
#endif /* BYTE_ORDER == BIG_ENDIAN */
#if BYTE_ORDER == LITTLE_ENDIAN
            unsigned        dub_sport: 8;
            unsigned        dub_dport: 8;
            unsigned        dub_len: 10;
            unsigned        dub_pad: 6;
#endif /* BYTE_ORDER == LITTLE_ENDIAN */
        } du_bits;
        unsigned    du_bytes;
    } dsh_u;
#define dsh_pad     dsh_u.du_bits.dub_pad
#define dsh_len     dsh_u.du_bits.dub_len
#define dsh_dport   dsh_u.du_bits.dub_dport
#define dsh_sport   dsh_u.du_bits.dub_sport
#define dsh_bytes   dsh_u.du_bytes
};
#define SZ_DDPSHDR      4
 
#endif /* netatalk/ddp.h */