/**
 * heartbeat.cpp
 * This file is part of the YATE Project http://YATE.null.ro
 *
 * Linux-HA compatible heartbeat module
 *
 * Yet Another Telephony Engine - a fully featured software PBX and IVR
 * Copyright (C) 2004-2006 Null Team
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 */


#include <yatengine.h>

#include <stdio.h>

#define AUTH_BLOCKSIZE 64

// This code is copied from plugins/HBauth/crc.c
static u_int32_t const s_crctab[256] =
{
	0x0,
	0x04C11DB7, 0x09823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B,
	0x1A864DB2, 0x1E475005, 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6,
	0x2B4BCB61, 0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD,
	0x4C11DB70, 0x48D0C6C7, 0x4593E01E, 0x4152FDA9, 0x5F15ADAC,
	0x5BD4B01B, 0x569796C2, 0x52568B75, 0x6A1936C8, 0x6ED82B7F,
	0x639B0DA6, 0x675A1011, 0x791D4014, 0x7DDC5DA3, 0x709F7B7A,
	0x745E66CD, 0x9823B6E0, 0x9CE2AB57, 0x91A18D8E, 0x95609039,
	0x8B27C03C, 0x8FE6DD8B, 0x82A5FB52, 0x8664E6E5, 0xBE2B5B58,
	0xBAEA46EF, 0xB7A96036, 0xB3687D81, 0xAD2F2D84, 0xA9EE3033,
	0xA4AD16EA, 0xA06C0B5D, 0xD4326D90, 0xD0F37027, 0xDDB056FE,
	0xD9714B49, 0xC7361B4C, 0xC3F706FB, 0xCEB42022, 0xCA753D95,
	0xF23A8028, 0xF6FB9D9F, 0xFBB8BB46, 0xFF79A6F1, 0xE13EF6F4,
	0xE5FFEB43, 0xE8BCCD9A, 0xEC7DD02D, 0x34867077, 0x30476DC0,
	0x3D044B19, 0x39C556AE, 0x278206AB, 0x23431B1C, 0x2E003DC5,
	0x2AC12072, 0x128E9DCF, 0x164F8078, 0x1B0CA6A1, 0x1FCDBB16,
	0x018AEB13, 0x054BF6A4, 0x0808D07D, 0x0CC9CDCA, 0x7897AB07,
	0x7C56B6B0, 0x71159069, 0x75D48DDE, 0x6B93DDDB, 0x6F52C06C,
	0x6211E6B5, 0x66D0FB02, 0x5E9F46BF, 0x5A5E5B08, 0x571D7DD1,
	0x53DC6066, 0x4D9B3063, 0x495A2DD4, 0x44190B0D, 0x40D816BA,
	0xACA5C697, 0xA864DB20, 0xA527FDF9, 0xA1E6E04E, 0xBFA1B04B,
	0xBB60ADFC, 0xB6238B25, 0xB2E29692, 0x8AAD2B2F, 0x8E6C3698,
	0x832F1041, 0x87EE0DF6, 0x99A95DF3, 0x9D684044, 0x902B669D,
	0x94EA7B2A, 0xE0B41DE7, 0xE4750050, 0xE9362689, 0xEDF73B3E,
	0xF3B06B3B, 0xF771768C, 0xFA325055, 0xFEF34DE2, 0xC6BCF05F,
	0xC27DEDE8, 0xCF3ECB31, 0xCBFFD686, 0xD5B88683, 0xD1799B34,
	0xDC3ABDED, 0xD8FBA05A, 0x690CE0EE, 0x6DCDFD59, 0x608EDB80,
	0x644FC637, 0x7A089632, 0x7EC98B85, 0x738AAD5C, 0x774BB0EB,
	0x4F040D56, 0x4BC510E1, 0x46863638, 0x42472B8F, 0x5C007B8A,
	0x58C1663D, 0x558240E4, 0x51435D53, 0x251D3B9E, 0x21DC2629,
	0x2C9F00F0, 0x285E1D47, 0x36194D42, 0x32D850F5, 0x3F9B762C,
	0x3B5A6B9B, 0x0315D626, 0x07D4CB91, 0x0A97ED48, 0x0E56F0FF,
	0x1011A0FA, 0x14D0BD4D, 0x19939B94, 0x1D528623, 0xF12F560E,
	0xF5EE4BB9, 0xF8AD6D60, 0xFC6C70D7, 0xE22B20D2, 0xE6EA3D65,
	0xEBA91BBC, 0xEF68060B, 0xD727BBB6, 0xD3E6A601, 0xDEA580D8,
	0xDA649D6F, 0xC423CD6A, 0xC0E2D0DD, 0xCDA1F604, 0xC960EBB3,
	0xBD3E8D7E, 0xB9FF90C9, 0xB4BCB610, 0xB07DABA7, 0xAE3AFBA2,
	0xAAFBE615, 0xA7B8C0CC, 0xA379DD7B, 0x9B3660C6, 0x9FF77D71,
	0x92B45BA8, 0x9675461F, 0x8832161A, 0x8CF30BAD, 0x81B02D74,
	0x857130C3, 0x5D8A9099, 0x594B8D2E, 0x5408ABF7, 0x50C9B640,
	0x4E8EE645, 0x4A4FFBF2, 0x470CDD2B, 0x43CDC09C, 0x7B827D21,
	0x7F436096, 0x7200464F, 0x76C15BF8, 0x68860BFD, 0x6C47164A,
	0x61043093, 0x65C52D24, 0x119B4BE9, 0x155A565E, 0x18197087,
	0x1CD86D30, 0x029F3D35, 0x065E2082, 0x0B1D065B, 0x0FDC1BEC,
	0x3793A651, 0x3352BBE6, 0x3E119D3F, 0x3AD08088, 0x2497D08D,
	0x2056CD3A, 0x2D15EBE3, 0x29D4F654, 0xC5A92679, 0xC1683BCE,
	0xCC2B1D17, 0xC8EA00A0, 0xD6AD50A5, 0xD26C4D12, 0xDF2F6BCB,
	0xDBEE767C, 0xE3A1CBC1, 0xE760D676, 0xEA23F0AF, 0xEEE2ED18,
	0xF0A5BD1D, 0xF464A0AA, 0xF9278673, 0xFDE69BC4, 0x89B8FD09,
	0x8D79E0BE, 0x803AC667, 0x84FBDBD0, 0x9ABC8BD5, 0x9E7D9662,
	0x933EB0BB, 0x97FFAD0C, 0xAFB010B1, 0xAB710D06, 0xA6322BDF,
	0xA2F33668, 0xBCB4666D, 0xB8757BDA, 0xB5365D03, 0xB1F740B4
};

static u_int32_t crc(const char* buf, unsigned int len)
{
	u_int32_t crc = 0;
	while (len--)
	    crc = (crc << 8) ^ s_crctab[((crc >> 24) ^ *(buf++)) & 0xFF];
	return ~crc;
}


using namespace TelEngine;
namespace { // anonymous

class TimerHandler : public MessageHandler
{
public:
    TimerHandler(unsigned int prio)
	: MessageHandler("engine.timer",prio)
	{ }
    virtual bool received(Message &msg);
};

class HaltHandler : public MessageHandler
{
public:
    HaltHandler(unsigned int prio)
	: MessageHandler("engine.halt",prio)
	{ }
    virtual bool received(Message &msg);
};

class HBeatPlugin : public Plugin, public Mutex
{
public:
    enum AuthType {
	AuthNone = 0,
	AuthCRC,
	AuthMD5,
	AuthSHA1,
    };
    HBeatPlugin();
    virtual ~HBeatPlugin();
    virtual void initialize();
    void sendHeartbeat(const Time& tStamp, bool goDown);
private:
    Socket m_socket;
    String m_node;
    String m_authKey;
    int m_seq;
    int m_ttl;
    int m_authIdx;
    AuthType m_authType;
};

static HBeatPlugin splugin;


void HBeatPlugin::sendHeartbeat(const Time& tStamp, bool goDown)
{
    lock();
    if (m_socket.valid()) {
	char hex[16];
	String buf;
	// Linux-HA relies on the fields order so don't change it. Thanks.
	buf << "t=status\n";
	if (goDown)
	    buf << "st=dead\n";
	else if (m_seq)
	    buf << "st=active\n";
	else
	    buf << "st=up\n";
	buf << "src=" << m_node << "\n";
	::snprintf(hex,sizeof(hex),"%x",++m_seq);
	buf << "seq=" << hex << "\n";
	::snprintf(hex,sizeof(hex),"%x",Engine::runId());
	buf << "hg=" << hex << "\n";
	::snprintf(hex,sizeof(hex),"%x",tStamp.sec());
	buf << "ts=" << hex << "\n";
	buf << "ld=n/a\n";
	buf << "ttl=" << m_ttl << "\n";
	if (m_authIdx > 0) {
	    DataBlock key((void*)m_authKey.c_str(),m_authKey.length());
	    switch (m_authType) {
		case AuthMD5:
		    if (key.length() > AUTH_BLOCKSIZE) {
			MD5 hash(key);
			key.assign((void*)hash.rawDigest(),hash.rawLength());
		    }
		    break;
		case AuthSHA1:
		    if (key.length() > AUTH_BLOCKSIZE) {
			SHA1 hash(key);
			key.assign((void*)hash.rawDigest(),hash.rawLength());
		    }
		    break;
		default:
		    break;
	    }
	    String tmp = "none";
	    const char* pkey = (const char*)key.data();
	    switch (m_authType) {
		case AuthMD5:
		    {
			unsigned char kbuf[AUTH_BLOCKSIZE];
			unsigned int i;
			for (i = 0; i < AUTH_BLOCKSIZE; i++)
			    kbuf[i] = 0x36 ^ (i < key.length() ? pkey[i] : 0);
			MD5 hash1(kbuf,AUTH_BLOCKSIZE);
			hash1.update(buf);
			for (i = 0; i < AUTH_BLOCKSIZE; i++)
			    kbuf[i] = 0x5c ^ (i < key.length() ? pkey[i] : 0);
			MD5 hash2(kbuf,AUTH_BLOCKSIZE);
			hash2.update((void*)hash1.rawDigest(),hash1.rawLength());
			tmp = hash2.hexDigest();
		    }
		    break;
		case AuthSHA1:
		    {
			// code duplication as we don't have a hash factory
			unsigned char kbuf[AUTH_BLOCKSIZE];
			unsigned int i;
			for (i = 0; i < AUTH_BLOCKSIZE; i++)
			    kbuf[i] = 0x36 ^ (i < key.length() ? pkey[i] : 0);
			SHA1 hash1(kbuf,AUTH_BLOCKSIZE);
			hash1.update(buf);
			for (i = 0; i < AUTH_BLOCKSIZE; i++)
			    kbuf[i] = 0x5c ^ (i < key.length() ? pkey[i] : 0);
			SHA1 hash2(kbuf,AUTH_BLOCKSIZE);
			hash2.update((void*)hash1.rawDigest(),hash1.rawLength());
			tmp = hash2.hexDigest();
		    }
		    break;
		case AuthCRC:
		    ::snprintf(hex,sizeof(hex),"%x",crc(buf.c_str(),buf.length()));
		    tmp = hex;
		default:
		    break;
	    }
	    buf << "auth=" << m_authIdx << " " << tmp << "\n";
	}
	buf = ">>>\n" + buf;
	buf << "<<<\n";
	// send the string including the terminating zero
	if (!m_socket.send(buf.c_str(),buf.length()+1))
	    Debug("heartbeat",DebugWarn,"Could not send Heartbeat packet, error: %d",m_socket.error());
	if (goDown)
	    m_socket.terminate();
    }
    unlock();
}


bool TimerHandler::received(Message &msg)
{
    splugin.sendHeartbeat(msg.msgTime(),Engine::exiting());
    return false;
}


bool HaltHandler::received(Message &msg)
{
    splugin.sendHeartbeat(msg.msgTime(),true);
    return false;
}


HBeatPlugin::HBeatPlugin()
    : Plugin("heartbeat"), Mutex(false,"HBeatPlugin"),
      m_seq(0), m_ttl(2), m_authIdx(0), m_authType(AuthNone)
{
    Output("Loaded module Heartbeat");
}

HBeatPlugin::~HBeatPlugin()
{
    Output("Unloading module Heartbeat");
    sendHeartbeat(Time(),true);
}

void HBeatPlugin::initialize()
{
    Configuration cfg(Engine::configFile("heartbeat"));
    Lock lock(this);
    m_authIdx = cfg.getIntValue("authentication","index");
    m_authKey = cfg.getValue("authentication","key");
    NamedString* auth = cfg.getKey("authentication","method");
    if (auth) {
	if (*auth == "crc")
	    m_authType = AuthCRC;
	else if (*auth == "md5")
	    m_authType = AuthMD5;
	else if (*auth == "sha1")
	    m_authType = AuthSHA1;
	else
	    m_authIdx = 0;
    }
    else
	m_authIdx = 0;
    if (!m_socket.valid()) {
	if (!cfg.getBoolValue("general","enabled",true))
	    return;
	m_node = cfg.getValue("general","node",Engine::nodeName());
	if (m_node.null())
	    return;
	SocketAddr addr(AF_INET);
	if (!addr.host(cfg.getValue("general","host")))
	    return;
	addr.port(cfg.getIntValue("general","port",694));
	if (!m_socket.create(AF_INET,SOCK_DGRAM,IPPROTO_UDP))
	    return;
	Output("Initializing module Heartbeat, node '%s' to %s:%d",
	    m_node.c_str(),addr.host().c_str(),addr.port());
#ifdef SO_BROADCAST
	int opt = 1;
	if (cfg.getBoolValue("general","broadcast",true) && !m_socket.setOption(SOL_SOCKET,SO_BROADCAST,&opt,sizeof(opt)))
	    Debug("heartbeat",DebugMild,"Could not enable broadcast on socket, error: %d",m_socket.error());
#endif
	if (!(m_socket.connect(addr) && m_socket.setBlocking())) {
	    Debug("heartbeat",DebugWarn,"Could not set up socket, error: %d",m_socket.error());
	    m_socket.terminate();
	    return;
	}
	m_ttl = cfg.getIntValue("general","ttl",2);
	if (m_ttl < 1)
	    m_ttl = 1;
	Engine::install(new TimerHandler(cfg.getIntValue("priorities","engine.timer",150)));
	Engine::install(new HaltHandler(cfg.getIntValue("priorities","engine.halt",50)));
    }
}

}; // anonymous namespace

/* vi: set ts=8 sw=4 sts=4 noet: */