PeerStreamer

/*

 *          Policy Management

 *

 *          NEC Europe Ltd. PROPRIETARY INFORMATION

 *

 * This software is supplied under the terms of a license agreement

 * or nondisclosure agreement with NEC Europe Ltd. and may not be

 * copied or disclosed except in accordance with the terms of that

 * agreement.

 *

 *      Copyright (c) 2009 NEC Europe Ltd. All Rights Reserved.

 *

 * Authors: Kristian Beckers  <beckers@nw.neclab.eu>

 *    Sebastian Kiesel  <kiesel@nw.neclab.eu>

 *          

 *

 * NEC Europe Ltd. DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED,

 * INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY

 * AND FITNESS FOR A PARTICULAR PURPOSE AND THE WARRANTY AGAINST LATENT

 * DEFECTS, WITH RESPECT TO THE PROGRAM AND THE ACCOMPANYING

 * DOCUMENTATION.

 *

 * No Liability For Consequential Damages IN NO EVENT SHALL NEC Europe

 * Ltd., NEC Corporation OR ANY OF ITS SUBSIDIARIES BE LIABLE FOR ANY

 * DAMAGES WHATSOEVER (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS

 * OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF INFORMATION, OR

 * OTHER PECUNIARY LOSS AND INDIRECT, CONSEQUENTIAL, INCIDENTAL,

 * ECONOMIC OR PUNITIVE DAMAGES) ARISING OUT OF THE USE OF OR INABILITY

 * TO USE THIS PROGRAM, EVEN IF NEC Europe Ltd. HAS BEEN ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGES.

 *

 *     THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.

 */

#include <assert.h>

#include <stdlib.h>   

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <stdio.h> 

#include <unistd.h>

#include <sys/ioctl.h>

#include <sys/socket.h>

#include <sys/time.h>

#include <sys/types.h> 

#include <arpa/inet.h>

#include <fcntl.h>

#include <netdb.h>

#include <netinet/in.h>

//#include <arpa/nameser.h>

//#include <resolv.h>

#include <net/if.h>

#include "ml_log.h"

#include "stun.h"

#include "udpSocket.h"

/// define a structure to hold a stun address             

const UInt8  IPv4Family = 0x01;

const UInt8  IPv6Family = 0x02;

// define  flags                                             

const UInt32 ChangeIpFlag   = 0x04;

const UInt32 ChangePortFlag = 0x02;

// define  stun attributes        

const UInt16 MappedAddress    = 0x0001;

const UInt16 ResponseAddress  = 0x0002;

const UInt16 ChangeRequest    = 0x0003;

const UInt16 SourceAddress    = 0x0004;

const UInt16 ChangedAddress   = 0x0005;

const UInt16 Username         = 0x0006;

const UInt16 Password         = 0x0007;

const UInt16 MessageIntegrity = 0x0008;

const UInt16 ErrorCode        = 0x0009;

const UInt16 UnknownAttribute = 0x000A;

const UInt16 ReflectedFrom    = 0x000B;

const UInt16 XorMappedAddress = 0x8020;

const UInt16 XorOnly          = 0x0021;

const UInt16 ServerName       = 0x8022;

const UInt16 SecondaryAddress = 0x8050; // Non standard extention       

// define types for a stun message                                 

const UInt16 BindRequestMsg               = 0x0001;

const UInt16 BindResponseMsg              = 0x0101;

const UInt16 BindErrorResponseMsg         = 0x0111;

const UInt16 SharedSecretRequestMsg       = 0x0002;

const UInt16 SharedSecretResponseMsg      = 0x0102;

const UInt16 SharedSecretErrorResponseMsg = 0x0112;

void pmtu_error_cb_stun(char *buf,int bufsize){

  printf("error: MTU size of stun message too big !");

}

/* sends a request to a stun server */

int send_stun_request(const int udpSocket,struct sockaddr_in *stunServ)

{

  assert( sizeof(UInt8 ) == 1 );

  assert( sizeof(UInt16) == 2 );

  assert( sizeof(UInt32) == 4 );

  bool verbose = false;

  //set the verbose mode 

  verbose = true;

  StunMessage req;

  memset(&req, 0, sizeof(StunMessage));

  StunAtrString username;

  StunAtrString password;

  username.sizeValue = 0;

  password.sizeValue = 0;

  /* build a stun request message  */

  /* creates a stun message struct with the given atributes  */

  stunBuildReqSimple( &req, username,

                      false , false ,

                      0x0c );

  /* buffer for the stun request  */

  char buf[STUN_MAX_MESSAGE_SIZE];

  int len = STUN_MAX_MESSAGE_SIZE;

  /* encode the stun message  */

  len = stunEncodeMessage( req, buf, len, password, verbose);

  struct iovec iov;

  iov.iov_len = len;

  iov.iov_base = buf;

  sendPacket(udpSocket,&iov,1,stunServ);

  return 0;

}

/* sends a keep alive to a server  */

int send_stun_keep_alive(const int udpSocket,struct sockaddr_in *stunServ)

{

  send_stun_request(udpSocket,stunServ);

  return 0;

}

/* parses a given stun message and sets the refelxive address  */

int recv_stun_message(char *msgbuf,int msgLen,StunMessage *response){

  //StunMessage resp;

  //memset(&resp, 0, sizeof(StunMessage));

  int returnValue = 0;

  //bool verbose = true;

  bool verbose = false;

  //printf("still alive 4 \n ");

  //if ( verbose ) printf("Got a response \n");

  bool ok = stunParseMessage(msgbuf, msgLen, response, verbose );

  if (!ok){

    returnValue = 1;

    error("parse STUN message failed \n");

  }

      UInt32 ip_addr = response->mappedAddress.ipv4.addr;

      char mapped_addr[16];

      int length;

      length = sprintf(mapped_addr,"%d.%d.%d.%d",(ip_addr >> 24) & 0xff,(ip_addr >> 16) & 0xff,(ip_addr >> 8) & 0xff,ip_addr & 0xff);

      ip_addr = response->changedAddress.ipv4.addr;

      char changed_addr[16];

      length = sprintf(changed_addr,"%d.%d.%d.%d",(ip_addr >> 24) & 0xff,(ip_addr >> 16)\

              & 0xff,(ip_addr >> 8) & 0xff,ip_addr & 0xff);

  if ( verbose )

  {

      info( "\t mappedAddr= ipv4 %s port %d \n \t changedAddr= ipv4 %s port %d \n",

              mapped_addr ,

              response->mappedAddress.ipv4.port,

              changed_addr,

              response->changedAddress.ipv4.port);

      }

  debug("still here");

  //reflexiveAddr.sin_addr.s_addr = inet_addr(changed_addr);

  //reflexiveAddr->sin_addr.s_addr = inet_addr("1.1.1.1");

  //reflexiveAddr->sin_port = htons(resp.mappedAddress.ipv4.port);

  return returnValue;

}

bool 

stunParseAtrAddress( char* body, unsigned int hdrLen, StunAtrAddress4 *result, bool verbose )

{

   if ( hdrLen != 8 )

   {

      error("hdrlen is not 8 \n ");

      return false;

   }

   result->pad = *body++;

   result->family = *body++;

   if (result->family == IPv4Family)

   {

      UInt16 nport;

      memcpy(&nport, body, 2); body+=2;

      if (verbose) info("port %i \n",ntohs(nport));

      result->ipv4.port = ntohs(nport);

      UInt32 naddr;

      memcpy(&naddr, body, 4); body+=4;

      //printf("port %d \n",ntohl(naddr));

      if (verbose)

        {

      UInt32 ip_addr = ntohl(naddr);

      char str_p[20];

      sprintf(str_p,"%d.%d.%d.%d",(ip_addr >> 24) & 0xff,(ip_addr >> 16) & 0xff,(ip_addr >> 8) & 0xff,ip_addr & 0xff);          

      info(" ipv4 as str %s \n  ",str_p);

        }

      result->ipv4.addr = ntohl(naddr);

      return true;

   }

   else if (result->family == IPv6Family)

   {

      warn("ipv6 not supported  \n");

   }

   else

   {

      error("bad address family: %i \n ",result->family );

   }

   return false;

}

bool

stunParseMessage( char* buf, unsigned int bufLen, StunMessage *msg, bool verbose)

{

  if (verbose) info("Received stun message: %d bytes \n",bufLen);

   memset(msg, 0, sizeof(msg));

   if (sizeof(StunMsgHdr) > bufLen)

   {

     error("Bad message \n");

      return false;

   }

   memcpy(&msg->msgHdr, buf, sizeof(StunMsgHdr));

   msg->msgHdr.msgType = ntohs(msg->msgHdr.msgType);

   msg->msgHdr.msgLength = ntohs(msg->msgHdr.msgLength);

   if (msg->msgHdr.msgLength + sizeof(StunMsgHdr) != bufLen)

   {

     error("Message header length doesn't match message size: %d - %d \n"

            ,msg->msgHdr.msgLength,bufLen);

      return false;

   }

   char* body = buf + sizeof(StunMsgHdr);

   unsigned int size = msg->msgHdr.msgLength;

   debug("bytes after header = %d",size);

   while ( size > 0 )

   {

      // !jf! should check that there are enough bytes left in the buffer

     StunAtrHdr* attr = (StunAtrHdr*)(body);

      unsigned int attrLen = ntohs(attr->length);

      int atrType = ntohs(attr->type);

      //if (verbose) clog << "Found attribute type=" << AttrNames[atrType] << " length=" << attrLen << endl;

      if ( attrLen+4 > size ) 

      {

        debug( "claims attribute is larger than size of message " \

                "(attribute type= %d \n" ,atrType);

         return false;

      }

      body += 4; // skip the length and type in attribute header

      size -= 4;

      if( atrType == MappedAddress)

      { 

        msg->hasMappedAddress = true;

        //printf("has mapped address \n");

        if ( stunParseAtrAddress(body, attrLen, &msg->mappedAddress, verbose) == false)

            {

                debug("problem parsing MappedAddress \n");

               return false;

            }

            else

            {

              if (verbose) {info("MappedAddress -------------------\n");}

            }

      }else 

      if (atrType == ResponseAddress)

        {

            msg->hasResponseAddress = true;

            if ( stunParseAtrAddress(  body,  attrLen,  &msg->responseAddress, verbose )== false )

            {

                    debug("problem parsing ResponseAddress \n");

              return false;

            }

            else

            {

              if (verbose) {info("ResponseAddress ---------------------\n");}

            }

        }else if(atrType == ChangeRequest)

        {

            msg->hasChangeRequest = true;

            if (stunParseAtrChangeRequest( body, attrLen, &msg->changeRequest) == false)

            {

                    debug("problem parsing ChangeRequest \n");

               return false;

            }

            else

            {

              if (verbose) info("ChangeRequest = %i \n",(int)&msg->changeRequest.value);

            }

        } else if (atrType == SourceAddress)

        {

            msg->hasSourceAddress = true;

            if ( stunParseAtrAddress(  body,  attrLen,  &msg->sourceAddress, verbose )== false )

            {

                    debug("problem parsing SourceAddress \n");

               return false;

            }

            else

            {

              if (verbose) info("SourceAddress ------------------\n");

            }

        } else if (atrType ==  ChangedAddress)

        {

            msg->hasChangedAddress = true;

            if ( stunParseAtrAddress(  body,  attrLen, &msg->changedAddress, verbose )== false )

            {

                    debug("problem parsing ChangedAddress \n");

               return false;

            }

            else

            {

              if (verbose) info("ChangedAddress = ---------------------\n");

            }

        } else if (atrType ==  Username) 

        {

            msg->hasUsername = true;

            if (stunParseAtrString( body, attrLen, &msg->username) == false)

            {

                    debug("problem parsing Username \n");

               return false;

            }

            else

            {

              if (verbose) info("Username = %s \n",msg->username.value);

            }

        }else if (atrType ==  Password) 

         {

            msg->hasPassword = true;

            if (stunParseAtrString( body, attrLen, &msg->password) == false)

            {

              debug("problem parsing Password \n");

               return false;

            }

            else

            {

              if (verbose) info("Password = %s \n",(char *)&msg->password.value);

            }

         }else if (atrType == MessageIntegrity)

        {

            msg->hasMessageIntegrity = true;

            if (stunParseAtrIntegrity( body, attrLen,&msg->messageIntegrity) == false)

            {

              debug("problem parsing MessageIntegrity \n");

               return false;

            }

            else

            {

               //if (verbose) clog << "MessageIntegrity = " << msg.messageIntegrity.hash << endl;

            }

            // read the current HMAC

            // look up the password given the user of given the transaction id 

            // compute the HMAC on the buffer

            // decide if they match or not

        } else if (atrType == ErrorCode)

        {

            msg->hasErrorCode = true;

            if (stunParseAtrError(body, attrLen, &msg->errorCode) == false)

            {

              debug("problem parsing ErrorCode \n");

               return false;

            }

            else

            {

              if (verbose) info("ErrorCode = %d %d %s \n",(int)(msg->errorCode.errorClass)                                 ,(int)(msg->errorCode.number)

                                 ,msg->errorCode.reason);

            }

        } else if (atrType == UnknownAttribute)

        {                        

            msg->hasUnknownAttributes = true;

            if (stunParseAtrUnknown(body, attrLen,&msg->unknownAttributes) == false)

            {

              debug("problem parsing UnknownAttribute \n");

               return false;

            }

        } else if (atrType == ReflectedFrom)

        {

            msg->hasReflectedFrom = true;

            if ( stunParseAtrAddress(  body,  attrLen,  &msg->reflectedFrom, verbose ) == false )

            {

              debug("problem parsing ReflectedFrom \n");

               return false;

            }

        } else if (atrType == XorMappedAddress)

        {                

            msg->hasXorMappedAddress = true;

            if ( stunParseAtrAddress(  body,  attrLen,  &msg->xorMappedAddress, verbose ) == false )

            {

              debug("problem parsing XorMappedAddress \n");

               return false;

            }

            else

            {

              if (verbose) info("XorMappedAddress ------------------- \n");

            }

        } else if (atrType == XorOnly)

        {

            msg->xorOnly = true;

            if (verbose) 

            {

              debug("xorOnly = true \n");

            }

        } else if (atrType == ServerName) 

        {                        

            msg->hasServerName = true;

            if (stunParseAtrString( body, attrLen, &msg->serverName) == false)

            {

              debug("problem parsing ServerName \n");

               return false;

            }

            else

            {

              if (verbose) info("ServerName = %s \n",(char *)&msg->serverName.value);

            }

        } else if (atrType == SecondaryAddress)

        {

            msg->hasSecondaryAddress = true;

            if ( stunParseAtrAddress(  body,  attrLen, &msg->secondaryAddress, verbose ) == false )

            {

              debug("problem parsing secondaryAddress \n");

               return false;

            }

            else

            {

              if (verbose) info("SecondaryAddress ---------------- \n");

            }

        }  else 

        {                                

           if (verbose) info("Unknown attribute: %i \n",atrType);

            if ( atrType <= 0x7FFF ) 

            {

               return false;

            }

        }

      body += attrLen;

      size -= attrLen;

   }

   return true;

}

void

stunBuildReqSimple(StunMessage* msg,

                    const StunAtrString username,

                    bool changePort, bool changeIp, unsigned int id )

{

   assert( msg );

   memset( msg , 0 , sizeof(*msg) );

   msg->msgHdr.msgType = BindRequestMsg;

   int i;        

   for (i=0; i<16; i=i+4 )

   {

      assert(i+3<16);

      int r = stunRand();

      msg->msgHdr.id.octet[i+0]= r>>0;

      msg->msgHdr.id.octet[i+1]= r>>8;

      msg->msgHdr.id.octet[i+2]= r>>16;

      msg->msgHdr.id.octet[i+3]= r>>24;

   }

   if ( id != 0 )

   {

      msg->msgHdr.id.octet[0] = id; 

   }

   msg->hasChangeRequest = true;

   msg->changeRequest.value =(changeIp?ChangeIpFlag:0) | 

      (changePort?ChangePortFlag:0);

   if ( username.sizeValue > 0 )

   {

      msg->hasUsername = true;

      msg->username = username;

   }

}

unsigned int

stunEncodeMessage( const StunMessage msg, 

                   char* buf, 

                   unsigned int bufLen, 

                   const StunAtrString password, 

                   bool verbose)

{

   assert(bufLen >= sizeof(StunMsgHdr));

   char* ptr = buf;

   ptr = encode16(ptr, msg.msgHdr.msgType);

   char* lengthp = ptr;

   ptr = encode16(ptr, 0);

   ptr = encode(ptr, (const char*)(msg.msgHdr.id.octet), sizeof(msg.msgHdr.id));

   if (verbose) debug("Encoding stun message: ");

   if (msg.hasMappedAddress)

   {

     //if (verbose) info("Encoding MappedAddress: %s \n",msg.mappedAddress.ipv4);

      ptr = encodeAtrAddress4 (ptr, MappedAddress, msg.mappedAddress);

   }

   if (msg.hasResponseAddress)

   {

     //if (verbose) info("Encoding ResponseAddress: %s \n",msg.responseAddress.ipv4);

      ptr = encodeAtrAddress4(ptr, ResponseAddress, msg.responseAddress);

   }

   if (msg.hasChangeRequest)

   {

     //if (verbose) info("Encoding ChangeRequest: %s \n",msg.changeRequest.value);

      ptr = encodeAtrChangeRequest(ptr, msg.changeRequest);

   }

   if (msg.hasSourceAddress)

   {

     //if (verbose) info("Encoding SourceAddress: %s \n ",msg.sourceAddress.ipv4);

      ptr = encodeAtrAddress4(ptr, SourceAddress, msg.sourceAddress);

   }

   if (msg.hasChangedAddress)

   {

     //if (verbose) info("Encoding ChangedAddress: %s \n ",msg.changedAddress.ipv4);

      ptr = encodeAtrAddress4(ptr, ChangedAddress, msg.changedAddress);

   }

   if (msg.hasUsername)

   {

     if (verbose) info("Encoding Username: %s \n", msg.username.value);

      ptr = encodeAtrString(ptr, Username, msg.username);

   }

   if (msg.hasPassword)

   {

     if (verbose) info("Encoding Password: %s \n ",msg.password.value);

      ptr = encodeAtrString(ptr, Password, msg.password);

   }

   if (msg.hasErrorCode)

   {

     if (verbose) info("Encoding ErrorCode: class= %d number= %d reason= %s \n"

                         ,(int)msg.errorCode.errorClass  

                         ,(int)msg.errorCode.number 

                         ,msg.errorCode.reason 

                         );

      ptr = encodeAtrError(ptr, msg.errorCode);

   }

   if (msg.hasUnknownAttributes)

   {

     if (verbose) info("Encoding UnknownAttribute: ??? \n");

      ptr = encodeAtrUnknown(ptr, msg.unknownAttributes);

   }

   if (msg.hasReflectedFrom)

   {

     //if (verbose) info("Encoding ReflectedFrom: %s \n ",msg.reflectedFrom.ipv4);

      ptr = encodeAtrAddress4(ptr, ReflectedFrom, msg.reflectedFrom);

   }

   if (msg.hasXorMappedAddress)

   {

     //if (verbose) info("Encoding XorMappedAddress: %s \n ",msg.xorMappedAddress.ipv4 );

      ptr = encodeAtrAddress4 (ptr, XorMappedAddress, msg.xorMappedAddress);

   }

   if (msg.xorOnly)

   {

     if (verbose) info("Encoding xorOnly: \n");

      ptr = encodeXorOnly( ptr );

   }

   if (msg.hasServerName)

   {

     if (verbose) info("Encoding ServerName: %s \n ",msg.serverName.value);

      ptr = encodeAtrString(ptr, ServerName, msg.serverName);

   }

   if (msg.hasSecondaryAddress)

   {

     //if (verbose) info("Encoding SecondaryAddress: %s \n", msg.secondaryAddress.ipv4);

      ptr = encodeAtrAddress4 (ptr, SecondaryAddress, msg.secondaryAddress);

   }

   if (password.sizeValue > 0)

   {

     if (verbose) info("HMAC with password: %s \n ",password.value);

      StunAtrIntegrity integrity;

      //computeHmac(integrity.hash, buf, (int)(ptr-buf) , password.value, password.sizeValue);

      ptr = encodeAtrIntegrity(ptr, integrity);

   }

   encode16(lengthp, (UInt16)(ptr - buf - sizeof(StunMsgHdr)));

   return (int)(ptr - buf);

}

int 

stunRand()

{

   // return 32 bits of random stuff

   assert( sizeof(int) == 4 );

   static bool init=false;

   if ( !init )

   { 

      init = true;

      UInt64 tick;

#if defined(__GNUC__) && ( defined(__i686__) || defined(__i386__) || defined(__amd64__) )

      asm("rdtsc" : "=A" (tick));

#elif defined (__SUNPRO_CC) || defined( __sparc__ )        

      tick = gethrtime();

#elif defined(__MACH__) 

      int fd=open("/dev/random",O_RDONLY);

      read(fd,&tick,sizeof(tick));

      closesocket(fd);

#else

#     error Need some way to seed the random number generator 

#endif 

      int seed = (int)(tick);

#ifdef WIN32

      srand(seed);

#else

      srandom(seed);

#endif

   }

   return random(); 

}

UInt64

stunGetSystemTimeSecs()

{

   UInt64 time=0;

#if defined(WIN32)  

   SYSTEMTIME t;

   // CJ TODO - this probably has bug on wrap around every 24 hours

   GetSystemTime( &t );

   time = (t.wHour*60+t.wMinute)*60+t.wSecond; 

#else

   struct timeval now;

   gettimeofday( &now , NULL );

   //assert( now );

   time = now.tv_sec;

#endif

   return time;

}

bool

stunParseServerName( char* name, StunAddress4 addr)

{

   assert(name);

   // TODO - put in DNS SRV stuff.

   bool ret = stunParseHostName( name, addr.addr, addr.port, 3478); 

   if ( ret != true ) 

   {

       addr.port=0xFFFF;

   }        

   return ret;

}

// returns true if it scucceeded

bool 

stunParseHostName( char* peerName,

               UInt32 ip,

               UInt16 portVal,

               UInt16 defaultPort )

{

   struct in_addr sin_addr;

   char host[512];

   strncpy(host,peerName,512);

   host[512-1]='\0';

   char* port = NULL;

   int portNum = defaultPort;

   // pull out the port part if present.

   char* sep = strchr(host,':');

   if ( sep == NULL )

   {

      portNum = defaultPort;

   }

   else

   {

      *sep = '\0';

      port = sep + 1;

      // set port part

      char* endPtr=NULL;

      portNum = strtol(port,&endPtr,10);

      if ( endPtr != NULL )

      {

         if ( *endPtr != '\0' )

         {

            portNum = defaultPort;

         }

      }

   }

   if ( portNum < 1024 ) return false;

   if ( portNum >= 0xFFFF ) return false;

   // figure out the host part 

   struct hostent* h;

   h = gethostbyname( host );

   if ( h == NULL )

   {

     //int err = getErrno();

      error("error was %d \n",errno);

      ip = ntohl( 0x7F000001L );

      return false;

   }

   else

   {

      sin_addr = *(struct in_addr*)h->h_addr;

      ip = ntohl( sin_addr.s_addr );

   }

   portVal = portNum;

   return true;

}

bool 

stunParseAtrChangeRequest( char* body, unsigned int hdrLen, StunAtrChangeRequest *result )

{

   if ( hdrLen != 4 )

   {

      error("hdr length = %d excepcting %d \n ",hdrLen,sizeof(result));

      error("Incorrect size for ChangeRequest \n ");

      return false;

   }

   else

   {

      memcpy(&result->value, body, 4);

      result->value = ntohl(result->value);

      return true;

   }

}

bool 

stunParseAtrUnknown( char* body, unsigned int hdrLen,  StunAtrUnknown *result)

{

   if ( hdrLen >= sizeof(StunAtrUnknown) )

   {

      return false;

   }

   else

   {

      if (hdrLen % 4 != 0) return false;

      result->numAttributes = hdrLen / 4;

      int i;

      for (i=0; i<result->numAttributes; i++)

      {

         memcpy(&result->attrType[i], body, 2); body+=2;

         result->attrType[i] = ntohs(result->attrType[i]);

      }

      return true;

   }

}

bool 

stunParseAtrString( char* body, unsigned int hdrLen,  StunAtrString *result )

{

   if ( hdrLen >= STUN_MAX_STRING )

   {

     debug( "String is too large \n");

      return false;

   }

   else

   {

      if (hdrLen % 4 != 0)

      {

        debug("Bad length string %d \n ",hdrLen);

         return false;

      }

      result->sizeValue = hdrLen;

      memcpy(&result->value, body, hdrLen);

      result->value[hdrLen] = 0;

      return true;

   }

}

bool 

stunParseAtrIntegrity( char* body, unsigned int hdrLen,StunAtrIntegrity *result )

{

   if ( hdrLen != 20)

   {

     debug("MessageIntegrity must be 20 bytes \n");

      return false;

   }

   else

   {

      memcpy(&result->hash, body, hdrLen);

      return true;

   }

}

void

stunCreateErrorResponse(StunMessage response, int cl, int number, const char* msg)

{

   response.msgHdr.msgType = BindErrorResponseMsg;

   response.hasErrorCode = true;

   response.errorCode.errorClass = cl;

   response.errorCode.number = number;

   strcpy(response.errorCode.reason, msg);

}

bool

stunParseAtrError(char* body,unsigned int hdrLen,StunAtrError *result)

{

   if ( hdrLen >= sizeof(StunAtrError) )

   {

      debug("head on Error too large \n  ");

      return false;

   }

   else

   {

      memcpy(&result->pad, body, 2); body+=2;

      result->pad = ntohs(result->pad);

      result->errorClass = *body++;

      result->number = *body++;

      result->sizeReason = hdrLen - 4;

      memcpy(&result->reason, body, result->sizeReason);

      result->reason[result->sizeReason] = 0;

      return true;

   }

}

char* 

encodeAtrString(char* ptr, UInt16 type, const StunAtrString atr)

{

   assert(atr.sizeValue % 4 == 0);

   ptr = encode16(ptr, type);

   ptr = encode16(ptr, atr.sizeValue);

   ptr = encode(ptr, atr.value, atr.sizeValue);

   return ptr;

}

char* 

encodeAtrIntegrity(char* ptr, const StunAtrIntegrity atr)

{

   ptr = encode16(ptr, MessageIntegrity);

   ptr = encode16(ptr, 20);

   ptr = encode(ptr, atr.hash, sizeof(atr.hash));

   return ptr;

}

char* 

encodeAtrError(char* ptr, const StunAtrError atr)

{

   ptr = encode16(ptr, ErrorCode);

   ptr = encode16(ptr, 6 + atr.sizeReason);

   ptr = encode16(ptr, atr.pad);

   *ptr++ = atr.errorClass;

   *ptr++ = atr.number;

   ptr = encode(ptr, atr.reason, atr.sizeReason);

   return ptr;

}

char* 

encodeAtrUnknown(char* ptr, const StunAtrUnknown atr)

{

   ptr = encode16(ptr, UnknownAttribute);

   ptr = encode16(ptr, 2+2*atr.numAttributes);

   int i;

   for (i=0; i<atr.numAttributes; i++)

   {

      ptr = encode16(ptr, atr.attrType[i]);

   }

   return ptr;

}

char* 

encodeAtrAddress4(char* ptr, UInt16 type, const StunAtrAddress4 atr)

{

   ptr = encode16(ptr, type);

   ptr = encode16(ptr, 8);

   *ptr++ = atr.pad;

   *ptr++ = IPv4Family;

   ptr = encode16(ptr, atr.ipv4.port);

   ptr = encode32(ptr, atr.ipv4.addr);

   return ptr;

}

char* 

encodeAtrChangeRequest(char* ptr, const StunAtrChangeRequest atr)

{

   ptr = encode16(ptr, ChangeRequest);

   ptr = encode16(ptr, 4);

   ptr = encode32(ptr, atr.value);

   return ptr;

}

char* 

encodeXorOnly(char* ptr)

{

   ptr = encode16(ptr, XorOnly );

   return ptr;

}

char* 

encode(char* buf, const char* data, unsigned int length)

{

  memcpy(buf, data, length);

  return buf + length;

}

char* 

encode16(char* buf, UInt16 data)

{

   UInt16 ndata = htons(data);

   memcpy(buf, (void*)(&ndata), sizeof(UInt16));

   return buf + sizeof(UInt16);

}

char* 

encode32(char* buf, UInt32 data)

{

   UInt32 ndata = htonl(data);

   memcpy(buf, (void*)(&ndata), sizeof(UInt32));

   return buf + sizeof(UInt32);

}

/// return a random number to use as a port 

int

stunRandomPort()

{

   int min=0x4000;

   int max=0x7FFF;

   int ret = stunRand();

   ret = ret|min;

   ret = ret&max;

   return ret;

}

void

toHex(const char* buffer, int bufferSize, char* output) 

{

   static char hexmap[] = "0123456789abcdef";

   const char* p = buffer;

   char* r = output;

   int i;

   for (i=0; i < bufferSize; i++)

   {

      unsigned char temp = *p++;

      int hi = (temp & 0xf0)>>4;

      int low = (temp & 0xf);

      *r++ = hexmap[hi];

      *r++ = hexmap[low];

   }

   *r = 0;

}