root/usr/src/cmd/mailx/hdr/configdefs.h
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/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * mailx -- a modified version of a University of California at Berkeley
 *      mail program
 *
 * This file contains the definitions of data structures used in
 * configuring the network behavior of Mail when replying.
 */

/*
 * The following constants are used when you are running 4.1a bsd or
 * later on a local network.  The name thus found is inserted
 * into the host table slot whose name was originally EMPTY.
 */
#define EMPTY           "** empty **"
#define EMPTYID         'E'

/*
 * The following data structure is the host table.  You must have
 * an entry here for your own machine, plus any special stuff you
 * expect the mailer to know about.  Not all hosts need be here, however:
 * mailx can dope out stuff about hosts on the fly by looking
 * at addresses.  The machines needed here are:
 *      1) The local machine
 *      2) Any machines on the path to a network gateway
 *      3) Any machines with nicknames that you want to have considered
 *         the same.
 * The machine id letters can be anything you like and are not seen
 * externally.  Be sure not to use characters with the 0200 bit set --
 * these have special meanings.
 */
struct netmach {
        char    *nt_machine;
        char    nt_mid;
        short   nt_type;
};

/*
 * Network type codes.  Basically, there is one for each different
 * network, if the network can be discerned by the separator character,
 * such as @ for the arpa net.  The purpose of these codes is to
 * coalesce cases where more than one character means the same thing,
 * such as % and @ for the arpanet.  Also, the host table uses a
 * bit map of these codes to show what it is connected to.
 * BN -- connected to Bell Net.
 * AN -- connected to ARPA net, SN -- connected to Schmidt net.
 */
#define AN      1                       /* Connected to ARPA net */
#define BN      2                       /* Connected to BTL net */
#define SN      4                       /* Connected to Schmidt net */

/*
 * Data structure for table mapping network characters to network types.
 */
struct ntypetab {
        char    nt_char;                /* Actual character separator */
        int     nt_bcode;               /* Type bit code */
};

/*
 * Codes for the "kind" of a network.  IMPLICIT means that if there are
 * physically several machines on the path, one does not list them in the
 * address.  The arpa net is like this.  EXPLICIT means you list them,
 * as in UUCP.
 * By the way, this distinction means we lose if anyone actually uses the
 * arpa net subhost convention: name@subhost@arpahost
 */
#define IMPLICIT        1
#define EXPLICIT        2

/*
 * Table for mapping a network code to its type -- IMPLICIT routing or
 * IMPLICIT routing.
 */
struct nkindtab {
        int     nk_type;                /* Its bit code */
        int     nk_kind;                /* Whether explicit or implicit */
};

/*
 * The following table gives the order of preference of the various
 * networks.  Thus, if we have a choice of how to get somewhere, we
 * take the preferred route.
 */
struct netorder {
        short   no_stat;
        char    no_char;
};

/*
 * External declarations for above defined tables.
 */
extern struct netmach netmach[];
extern struct ntypetab ntypetab[];
extern struct nkindtab nkindtab[];
extern struct netorder netorder[];
extern char *metanet;