usr/src/include/protocols/talkd.h

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)talkd.h     5.5 (Berkeley) %G%
 */

#include <sys/types.h>
#include <sys/socket.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.
 */

/*
 * Client->server request message format.
 */
typedef struct {
        u_char  vers;           /* protocol version */
        u_char  type;           /* request type, see below */
        u_char  answer;         /* not used */
        u_char  pad;
        u_long  id_num;         /* message id */
        struct  osockaddr addr;         /* old (4.3) style */
        struct  osockaddr ctl_addr;     /* old (4.3) style */
        long    pid;            /* caller's process id */
#define NAME_SIZE       12
        char    l_name[NAME_SIZE];/* caller's name */
        char    r_name[NAME_SIZE];/* callee's name */
#define TTY_SIZE        16
        char    r_tty[TTY_SIZE];/* callee's tty name */
} CTL_MSG;

/*
 * Server->client response message format.
 */
typedef struct {
        u_char  vers;           /* protocol version */
        u_char  type;           /* type of request message, see below */
        u_char  answer;         /* respose to request message, see below */
        u_char  pad;
        u_long  id_num;         /* message id */
        struct  osockaddr 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.
 */
#define MAX_LIFE        60      /* max time daemon saves invitations */
/* RING_WAIT should be 10's of seconds less than MAX_LIFE */
#define RING_WAIT       30      /* time to wait before resending invitation */