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prot_talkd.h

/*
 * Copyright (c) 1983, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *    @(#)talkd.h 8.1 (Berkeley) 6/2/93
 */

#ifndef _PROTOCOLS_TALKD_H
#define     _PROTOCOLS_TALKD_H

/*
 * This describes the protocol used by the talk server and clients.
 *
 * The talk server acts a repository of invitations, responding to
 * requests by clients wishing to rendezvous for the purpose of
 * holding a conversation.  In normal operation, a client, the caller,
 * initiates a rendezvous by sending a CTL_MSG to the server of
 * type LOOK_UP.  This causes the server to search its invitation
 * tables to check if an invitation currently exists for the caller
 * (to speak to the callee specified in the message).  If the lookup
 * fails, the caller then sends an ANNOUNCE message causing the server
 * to broadcast an announcement on the callee's login ports requesting
 * contact.  When the callee responds, the local server uses the
 * recorded invitation to respond with the appropriate rendezvous
 * address and the caller and callee client programs establish a
 * stream connection through which the conversation takes place.
 */

#include <sys/types.h>

/*
 * This is a copy of 4.3BSD struct sockaddr.
 */
struct talk_addr {
  u_int16_t ta_family;
  u_int16_t ta_port;
  u_int32_t ta_addr;
  u_int32_t ta_junk1;
  u_int32_t ta_junk2;
};


/*
 * Client->server request message format.
 */
#define     NAME_SIZE   12
#define     TTY_SIZE    16

typedef struct {
      u_int8_t    vers;       /* protocol version */
      u_int8_t    type;       /* request type, see below */
      u_int8_t    answer;           /* not used */
      u_int8_t    pad;
      u_int32_t   id_num;           /* message id */
      struct talk_addr addr;        /* address of client tcp port */
      struct talk_addr ctl_addr;    /* address of client udp port */
      u_int32_t   pid;        /* caller's process id */
      char        l_name[NAME_SIZE];/* caller's name */
      char        r_name[NAME_SIZE];/* callee's name */
      char        r_tty[TTY_SIZE];/* callee's tty name */
} CTL_MSG;

/*
 * Server->client response message format.
 */
typedef struct {
      u_int8_t    vers; /* protocol version */
      u_int8_t    type; /* type of request message, see below */
      u_int8_t    answer;     /* respose to request message, see below */
      u_int8_t    pad;
      u_int32_t   id_num;     /* message id */
      struct      talk_addr addr;   /* address for establishing conversation */
} CTL_RESPONSE;

#define     TALK_VERSION      1           /* protocol version */

/* message type values */
#define LEAVE_INVITE    0     /* leave invitation with server */
#define LOOK_UP         1     /* check for invitation by callee */
#define DELETE          2     /* delete invitation by caller */
#define ANNOUNCE  3     /* announce invitation by caller */

/* answer values */
#define SUCCESS         0     /* operation completed properly */
#define NOT_HERE  1     /* callee not logged in */
#define FAILED          2     /* operation failed for unexplained reason */
#define MACHINE_UNKNOWN 3     /* caller's machine name unknown */
#define PERMISSION_DENIED 4   /* callee's tty doesn't permit announce */
#define UNKNOWN_REQUEST 5     /* request has invalid type value */
#define     BADVERSION  6     /* request has invalid protocol version */
#define     BADADDR           7     /* request has invalid addr value */
#define     BADCTLADDR  8     /* request has invalid ctl_addr value */

/*
 * Operational parameters.
 * RING_WAIT should be 10's of seconds less than MAX_LIFE
 */
#define MAX_LIFE  60    /* max time daemon saves invitations */
#define RING_WAIT 30    /* time to wait before resending invitation */

#endif /* !_PROTOCOLS_TALKD_H */

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