1 /* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)talkd.h 5.6 (Berkeley) 02/26/91 8 */ 9 10 /* 11 * This describes the protocol used by the talk server and clients. 12 * 13 * The talk server acts a repository of invitations, responding to 14 * requests by clients wishing to rendezvous for the purpose of 15 * holding a conversation. In normal operation, a client, the caller, 16 * initiates a rendezvous by sending a CTL_MSG to the server of 17 * type LOOK_UP. This causes the server to search its invitation 18 * tables to check if an invitation currently exists for the caller 19 * (to speak to the callee specified in the message). If the lookup 20 * fails, the caller then sends an ANNOUNCE message causing the server 21 * to broadcast an announcement on the callee's login ports requesting 22 * contact. When the callee responds, the local server uses the 23 * recorded invitation to respond with the appropriate rendezvous 24 * address and the caller and callee client programs establish a 25 * stream connection through which the conversation takes place. 26 */ 27 28 /* 29 * Client->server request message format. 30 */ 31 typedef struct { 32 u_char vers; /* protocol version */ 33 u_char type; /* request type, see below */ 34 u_char answer; /* not used */ 35 u_char pad; 36 u_long id_num; /* message id */ 37 struct osockaddr addr; /* old (4.3) style */ 38 struct osockaddr ctl_addr; /* old (4.3) style */ 39 long pid; /* caller's process id */ 40 #define NAME_SIZE 12 41 char l_name[NAME_SIZE];/* caller's name */ 42 char r_name[NAME_SIZE];/* callee's name */ 43 #define TTY_SIZE 16 44 char r_tty[TTY_SIZE];/* callee's tty name */ 45 } CTL_MSG; 46 47 /* 48 * Server->client response message format. 49 */ 50 typedef struct { 51 u_char vers; /* protocol version */ 52 u_char type; /* type of request message, see below */ 53 u_char answer; /* respose to request message, see below */ 54 u_char pad; 55 u_long id_num; /* message id */ 56 struct osockaddr addr; /* address for establishing conversation */ 57 } CTL_RESPONSE; 58 59 #define TALK_VERSION 1 /* protocol version */ 60 61 /* message type values */ 62 #define LEAVE_INVITE 0 /* leave invitation with server */ 63 #define LOOK_UP 1 /* check for invitation by callee */ 64 #define DELETE 2 /* delete invitation by caller */ 65 #define ANNOUNCE 3 /* announce invitation by caller */ 66 67 /* answer values */ 68 #define SUCCESS 0 /* operation completed properly */ 69 #define NOT_HERE 1 /* callee not logged in */ 70 #define FAILED 2 /* operation failed for unexplained reason */ 71 #define MACHINE_UNKNOWN 3 /* caller's machine name unknown */ 72 #define PERMISSION_DENIED 4 /* callee's tty doesn't permit announce */ 73 #define UNKNOWN_REQUEST 5 /* request has invalid type value */ 74 #define BADVERSION 6 /* request has invalid protocol version */ 75 #define BADADDR 7 /* request has invalid addr value */ 76 #define BADCTLADDR 8 /* request has invalid ctl_addr value */ 77 78 /* 79 * Operational parameters. 80 */ 81 #define MAX_LIFE 60 /* max time daemon saves invitations */ 82 /* RING_WAIT should be 10's of seconds less than MAX_LIFE */ 83 #define RING_WAIT 30 /* time to wait before resending invitation */ 84