/*
 * SRT - Secure, Reliable, Transport
 * Copyright (c) 2018 Haivision Systems Inc.
 * 
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 * 
 */

/*****************************************************************************
Copyright (c) 2001 - 2011, The Board of Trustees of the University of Illinois.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* 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.

* Neither the name of the University of Illinois
  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 COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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*****************************************************************************/

#include "platform_sys.h"

#include <cstring>
#include <string>
#include <sstream>
#include <iterator>
#include <algorithm>

#include "udt.h"
#include "core.h"
#include "handshake.h"
#include "utilities.h"

using namespace std;


CHandShake::CHandShake():
m_iVersion(0),
m_iType(0), // Universal: UDT_UNDEFINED or no flags
m_iISN(0),
m_iMSS(0),
m_iFlightFlagSize(0),
m_iReqType(URQ_WAVEAHAND),
m_iID(0),
m_iCookie(0),
m_extension(false)
{
   for (int i = 0; i < 4; ++ i)
      m_piPeerIP[i] = 0;
}

int CHandShake::store_to(char* buf, size_t& w_size)
{
   if (w_size < m_iContentSize)
      return -1;

   int32_t* p = reinterpret_cast<int32_t*>(buf);
   *p++ = m_iVersion;
   *p++ = m_iType;
   *p++ = m_iISN;
   *p++ = m_iMSS;
   *p++ = m_iFlightFlagSize;
   *p++ = int32_t(m_iReqType);
   *p++ = m_iID;
   *p++ = m_iCookie;
   for (int i = 0; i < 4; ++ i)
      *p++ = m_piPeerIP[i];

   w_size = m_iContentSize;

   return 0;
}

int CHandShake::load_from(const char* buf, size_t size)
{
   if (size < m_iContentSize)
      return -1;

   const int32_t* p = reinterpret_cast<const int32_t*>(buf);

   m_iVersion = *p++;
   m_iType = *p++;
   m_iISN = *p++;
   m_iMSS = *p++;
   m_iFlightFlagSize = *p++;
   m_iReqType = UDTRequestType(*p++);
   m_iID = *p++;
   m_iCookie = *p++;
   for (int i = 0; i < 4; ++ i)
      m_piPeerIP[i] = *p++;

   return 0;
}

#ifdef ENABLE_LOGGING

const char* srt_rejectreason_name [] = {
    "UNKNOWN",
    "SYSTEM",
    "PEER",
    "RESOURCE",
    "ROGUE",
    "BACKLOG",
    "IPE",
    "CLOSE",
    "VERSION",
    "RDVCOOKIE",
    "BADSECRET",
    "UNSECURE",
    "MESSAGEAPI",
    "CONGESTION",
    "FILTER",
};

std::string RequestTypeStr(UDTRequestType rq)
{
    if (rq >= URQ_FAILURE_TYPES)
    {
        std::ostringstream rt;
        rt << "ERROR:";
        int id = RejectReasonForURQ(rq);
        if (id < SRT_REJ_E_SIZE)
            rt << srt_rejectreason_name[id];
        else if (id < SRT_REJC_USERDEFINED)
        {
            if (id < SRT_REJC_PREDEFINED)
                rt << "UNKNOWN:" << id;
            else
                rt << "PREDEFINED:" << (id - SRT_REJC_PREDEFINED);
        }
        else
            rt << "USERDEFINED:" << (id - SRT_REJC_USERDEFINED);

        return rt.str();
    }

    switch ( rq )
    {
    case URQ_INDUCTION: return "induction";
    case URQ_WAVEAHAND: return "waveahand";
    case URQ_CONCLUSION: return "conclusion";
    case URQ_AGREEMENT: return "agreement";

    default: return "INVALID";
    }
}

string CHandShake::RdvStateStr(CHandShake::RendezvousState s)
{
    switch (s)
    {
    case RDV_WAVING: return "waving";
    case RDV_ATTENTION: return "attention";
    case RDV_FINE: return "fine";
    case RDV_INITIATED: return "initiated";
    case RDV_CONNECTED: return "connected";
    default: ;
    }

    return "invalid";
}
#endif

string CHandShake::show()
{
    ostringstream so;

    so << "version=" << m_iVersion << " type=0x" << hex << m_iType << dec
        << " ISN=" << m_iISN << " MSS=" << m_iMSS << " FLW=" << m_iFlightFlagSize
        << " reqtype=" << RequestTypeStr(m_iReqType) << " srcID=" << m_iID
        << " cookie=" << hex << m_iCookie << dec
        << " srcIP=";

    const unsigned char* p  = (const unsigned char*)m_piPeerIP;
    const unsigned char* pe = p + 4 * (sizeof(uint32_t));

    copy(p, pe, ostream_iterator<unsigned>(so, "."));

    // XXX HS version symbols should be probably declared inside
    // CHandShake, not CUDT.
    if ( m_iVersion > CUDT::HS_VERSION_UDT4 )
    {
        const int flags = SrtHSRequest::SRT_HSTYPE_HSFLAGS::unwrap(m_iType);
        so << "FLAGS: ";
        if (flags == SrtHSRequest::SRT_MAGIC_CODE)
            so << "MAGIC";
        else if (m_iType == 0)
            so << "NONE"; // no flags and no advertised pbkeylen
        else
            so << ExtensionFlagStr(m_iType);
    }

    return so.str();
}

string CHandShake::ExtensionFlagStr(int32_t fl)
{
    std::ostringstream out;
    if ( fl & HS_EXT_HSREQ )
        out << " hsx";
    if ( fl & HS_EXT_KMREQ )
        out << " kmx";
    if ( fl & HS_EXT_CONFIG )
        out << " config";

    const int kl = SrtHSRequest::SRT_HSTYPE_ENCFLAGS::unwrap(fl) << 6;
    if (kl != 0)
    {
        out << " AES-" << kl;
    }
    else
    {
        out << " no-pbklen";
    }

    return out.str();
}


// XXX This code isn't currently used. Left here because it can
// be used in future, should any refactoring for the "manual word placement"
// code be done.
bool SrtHSRequest::serialize(char* buf, size_t size) const
{
    if (size < SRT_HS_SIZE)
        return false;

    int32_t* p = reinterpret_cast<int32_t*>(buf);

    *p++ = m_iSrtVersion;
    *p++ = m_iSrtFlags;
    *p++ = m_iSrtTsbpd;
    *p++ = 0; // SURPRISE! Seriously, use (something) if this "reserved" is going to be used for something.
    return true;
}


bool SrtHSRequest::deserialize(const char* buf, size_t size)
{
    m_iSrtVersion = 0; // just to let users recognize if it succeeded or not.

    if (size < SRT_HS_SIZE)
        return false;

   const int32_t* p = reinterpret_cast<const int32_t*>(buf);

    m_iSrtVersion = (*p++);
    m_iSrtFlags = (*p++);
    m_iSrtTsbpd = (*p++);
    m_iSrtReserved = (*p++);
    return true;
}