protocol.h

Intercom 是一个 Unix系统上灵活的语音传输软件。支持标准音频压缩比如GSM, G.711, and G.72x和其他音频编码。Intercom专为高速网络设计来传输高品质的语音

/*  protocol.h -- Intercom protocol definition
    Copyright (C) 2001-2003  Shane Wegner
    This file is part of Intercom.

    Intercom is free software; you can redistribute it and/or modify it
    under the terms of version 2 of the GNU General Public License as
    published by the Free Software Foundation.

    Intercom is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    General Public License for more details.

    You should have received a copy of version 2 of the GNU General Public
    License along with Intercom; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

    To contact the author, please send email to [e-mail].
    */

/* $Id: protocol.h,v 1.14 2003/02/13 20:22:49 shane Exp $ */

#ifndef PROTOCOL_H
#define PROTOCOL_H

#ifdef HAVE_STDINT_H
#include <stdint.h>
#else
#include <inttypes.h>
#endif

#define INTERCOM_PROTOCOL_VERSION 1

struct pkt_header {
uint16_t p_len; /* Length of the packet including this header */
uint16_t p_type;
};

/* Valid packet types */
/* Upon connection, both peers must send a hello packet */
#define PKT_TYPE_HELLO 0 /* Hello packet */
#define PKT_TYPE_CALL 1 /* Incoming call */
#define PKT_TYPE_CALLRESPONSE 2 /* Response to incoming call */
#define PKT_TYPE_ERROR 3 /* Error condition */
#define PKT_TYPE_AUDIOSTART 4 /* Ok to start sending audio data */
#define PKT_TYPE_USRTEXT 5 /* User to user text message */

struct pkt_hello {
uint32_t proto_version;
char username[128]; /* username or other identifying string */
char clientname[128]; /* Client name and version */
};

struct audio_params {
uint8_t compression;
uint8_t bitwidth; /* Currently always 16 */
uint32_t rate; /* Sampling rate */
};

struct cryptinfo {
uint8_t type;
char challenge[128]; /* Challenge string */
char challenge_sha1[20]; /* SHA-1 of decrypted challenge string */
};

#define CALL_CRYPT_NONE 0
#define CALL_CRYPT_DES 1
#define CALL_CRYPT_BLOWFISH 2

struct pkt_call {
struct cryptinfo cryptinfo;
struct audio_params aparams; /* audio format caller will be sending */
};

struct pkt_callresponse {
uint8_t responsecode;
struct audio_params aparams; /* Format responder will be sending */
};

#define CALLRESPONSE_ACCEPT 0 /* Call was accepted, ok to send audio data */
#define CALLRESPONSE_DENY 1 /* Call was denied */

struct pkt_error {
uint16_t errorcode;
char errormsg[120]; /* Textual error message (null terminated). */
};

/* If this bit is set, the error is fatal and the call is invalidated. */
#define PKT_ERROR_FATAL 0x8000
#define PKT_ERROR_PKTUNKNOWN 0 /* Unknown packet type */
#define PKT_ERROR_PKTORDER 1 /* Unexpected or out of order packet */
#define PKT_ERROR_AUDIOFMT 2 /* Cannot support your audio format */
#define PKT_ERROR_PROTO_VERSION 3 /* Cannot support this protocol version */
#define PKT_ERROR_NOCRYPT 4 /* Encryption type not supported or encryption not enabled */

#define AUDIO_COMPRESSION_NONE 0
#define AUDIO_COMPRESSION_GSM 1 
#define AUDIO_COMPRESSION_G711U 2
#define AUDIO_COMPRESSION_G711A 3
#define AUDIO_COMPRESSION_G721 4
#define AUDIO_COMPRESSION_G723_24 5
#define AUDIO_COMPRESSION_G723_40 6

struct pkt_audiostart {
uint16_t dport; /* UDP data port to which to send audio data */
};

/* Packet type USRTEXT has no associated structure.  The data is simply */
/* the text message which is not null terminated. */

struct pkt_udpaudio {
uint16_t datalen;
uint32_t sequence;
};

#endif