srs/trunk/3rdparty/srt-1-fit/srtcore/handshake.cpp

/*
 * 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/.
 * 
 */

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#include "platform_sys.h"

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

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

using namespace std;
using namespace srt;


srt::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 srt::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 srt::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

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

std::string srt::RequestTypeStr(UDTRequestType rq)
{
    if (rq >= URQ_FAILURE_TYPES)
    {
        std::ostringstream rt;
        rt << "ERROR:";
        int id = RejectReasonForURQ(rq);
        if (id < (int) Size(srt_rejectreason_name))
            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 srt::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

bool srt::CHandShake::valid()
{
    if (m_iVersion < CUDT::HS_VERSION_UDT4
            || m_iISN < 0 || m_iISN >= CSeqNo::m_iMaxSeqNo
            || m_iMSS < 32
            || m_iFlightFlagSize < 2)
        return false;

    return true;
}

string srt::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 srt::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 srt::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 srt::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;
}

std::string srt::SrtFlagString(int32_t flags)
{
#define LEN(arr) (sizeof (arr)/(sizeof ((arr)[0])))

    std::string output;
    static std::string namera[] = { "TSBPD-snd", "TSBPD-rcv", "haicrypt", "TLPktDrop", "NAKReport", "ReXmitFlag", "StreamAPI" };

    size_t i = 0;
    for (; i < LEN(namera); ++i)
    {
        if ((flags & 1) == 1)
        {
            output += "+" + namera[i] + " ";
        }
        else
        {
            output += "-" + namera[i] + " ";
        }

        flags >>= 1;
    }

#undef LEN

    if (flags != 0)
    {
        output += "+unknown";
    }

    return output;
}