librecon-1.9-dev 1.9.6-1 / usr / include / reflow / dtls_wrapper / DtlsSocket.hxx

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef USE_SSL

#ifndef DtlsSocket_hxx
#define DtlsSocket_hxx

#include <memory>
extern "C" 
{
#ifdef WIN32
#include <srtp.h>
#else
#include <srtp/srtp.h>
#endif
}

#include <openssl/e_os2.h>
#include <openssl/rand.h>
#include <openssl/err.h>
#include <openssl/crypto.h>
#include <openssl/ssl.h>

namespace dtls
{
class DtlsFactory;
class DtlsSocket;
class DtlsTimer;

class DtlsSocketContext
{
   public:
      //memory is only valid for duration of callback; must be copied if queueing
      //is required 
      virtual ~DtlsSocketContext(){}      
      virtual void write(const unsigned char* data, unsigned int len)=0;
      virtual void handshakeCompleted()=0;
      virtual void handshakeFailed(const char *err)=0;

   protected:
      DtlsSocket *mSocket;
     
   private:
      friend class DtlsSocket;
     
      void setDtlsSocket(DtlsSocket *sock) {mSocket=sock;}
};

class SrtpSessionKeys
{
   public:
      unsigned char *clientMasterKey;
      int clientMasterKeyLen;
      unsigned char *serverMasterKey;
      int serverMasterKeyLen;
      unsigned char *clientMasterSalt;
      int clientMasterSaltLen;
      unsigned char *serverMasterSalt;
      int serverMasterSaltLen;
};

class DtlsSocketTimer;
   
class DtlsSocket
{
   public:
	   enum SocketType { Client, Server};
      ~DtlsSocket(); 

      // Inspects packet to see if it's a DTLS packet, if so continue processing
      bool handlePacketMaybe(const unsigned char* bytes, unsigned int len);
      
      // Called by DtlSocketTimer when timer expires - causes a retransmission (forceRetransmit)
      void expired(DtlsSocketTimer*);
      
      // Retrieves the finger print of the certificate presented by the remote party
      bool getRemoteFingerprint(char *fingerprint);

      // Retrieves the finger print of the certificate presented by the remote party and checks
      // it agains the passed in certificate
      bool checkFingerprint(const char* fingerprint, unsigned int len);

      // Retrieves the finger print of our local certificate, same as getMyCertFingerprint from DtlsFactory
      void getMyCertFingerprint(char *fingerprint);

      // For client sockets only - causes a client handshake to start (doHandshakeIteration)
      void startClient();

      // Returns the socket type: Client or Server
	   SocketType getSocketType() {return mSocketType;} 

      // Retreives the SRTP session keys from the Dtls session
      SrtpSessionKeys getSrtpSessionKeys();

      // Utility fn to compute a certificates fingerprint
      static void computeFingerprint(X509 *cert, char *fingerprint);
 
      // Retrieves the DTLS negotiated SRTP profile - may return 0 if profile selection failed
      SRTP_PROTECTION_PROFILE* getSrtpProfile();      

      // Creates SRTP session policies appropriately based on socket type (client vs server) and keys
      // extracted from the DTLS handshake process
      void createSrtpSessionPolicies(srtp_policy_t& outboundPolicy, srtp_policy_t& inboundPolicy);      
      
      // returns true if the DTLS handshake has completed
      bool handshakeCompleted() { return mHandshakeCompleted; }

      DtlsSocketContext* getSocketContext() { return mSocketContext.get(); }

   private:
      friend class DtlsFactory;

      // Causes an immediate handshake iteration to happen, which will retransmit the handshake
      void forceRetransmit();     

      // Creates an SSL socket, and if client sets state to connect_state and if server sets state to accept_state.  Sets SSL BIO's.
      DtlsSocket(std::auto_ptr<DtlsSocketContext> socketContext, DtlsFactory* factory, enum SocketType);

      // Give CPU cyces to the handshake process - checks current state and acts appropraitely
      void doHandshakeIteration();

      // returns the amount of time between handshake retranmssions (500ms)
      int getReadTimeout();
      
      // Internals
      std::auto_ptr<DtlsSocketContext> mSocketContext;
      DtlsFactory* mFactory;
      DtlsTimer *mReadTimer;  // Timer used during handshake process
      
      // OpenSSL context data    
      SSL *mSsl;      
      BIO *mInBio;
      BIO *mOutBio;
      
      SocketType mSocketType;
      bool mHandshakeCompleted;      
};

}
#endif

#endif 
/* ====================================================================

 Copyright (c) 2007-2008, Eric Rescorla and Derek MacDonald 
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    permission. 
 
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