talk/base/sslstreamadapter.h

/*
 * libjingle
 * Copyright 2004--2008, Google Inc.
 *
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 * modification, are permitted provided that the following conditions are met:
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 *     derived from this software without specific prior written permission.
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 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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#ifndef TALK_BASE_SSLSTREAMADAPTER_H__
#define TALK_BASE_SSLSTREAMADAPTER_H__

#include <string>

#include "talk/base/stream.h"
#include "talk/base/sslidentity.h"

namespace talk_base {

// SSLStreamAdapter : A StreamInterfaceAdapter that does SSL/TLS.
// After SSL has been started, the stream will only open on successful
// SSL verification of certificates, and the communication is
// encrypted of course.
//
// This class was written with SSLAdapter as a starting point. It
// offers a similar interface, with two differences: there is no
// support for a restartable SSL connection, and this class has a
// peer-to-peer mode.
//
// The SSL library requires initialization and cleanup. Static method
// for doing this are in SSLAdapter. They should possibly be moved out
// to a neutral class.


enum SSLRole { SSL_CLIENT, SSL_SERVER };
enum SSLMode { SSL_MODE_TLS, SSL_MODE_DTLS };

// Errors for Read -- in the high range so no conflict with OpenSSL.
enum { SSE_MSG_TRUNC = 0xff0001 };

class SSLStreamAdapter : public StreamAdapterInterface {
 public:
  // Instantiate an SSLStreamAdapter wrapping the given stream,
  // (using the selected implementation for the platform).
  // Caller is responsible for freeing the returned object.
  static SSLStreamAdapter* Create(StreamInterface* stream);

  explicit SSLStreamAdapter(StreamInterface* stream)
      : StreamAdapterInterface(stream), ignore_bad_cert_(false) { }

  void set_ignore_bad_cert(bool ignore) { ignore_bad_cert_ = ignore; }
  bool ignore_bad_cert() const { return ignore_bad_cert_; }

  // Specify our SSL identity: key and certificate. Mostly this is
  // only used in the peer-to-peer mode (unless we actually want to
  // provide a client certificate to a server).
  // SSLStream takes ownership of the SSLIdentity object and will
  // free it when appropriate. Should be called no more than once on a
  // given SSLStream instance.
  virtual void SetIdentity(SSLIdentity* identity) = 0;

  // Call this to indicate that we are to play the server's role in
  // the peer-to-peer mode.
  // The default argument is for backward compatibility
  // TODO(ekr@rtfm.com): rename this SetRole to reflect its new function
  virtual void SetServerRole(SSLRole role = SSL_SERVER) = 0;

  // Do DTLS or TLS
  virtual void SetMode(SSLMode mode) = 0;

  // The mode of operation is selected by calling either
  // StartSSLWithServer or StartSSLWithPeer.
  // Use of the stream prior to calling either of these functions will
  // pass data in clear text.
  // Calling one of these functions causes SSL negotiation to begin as
  // soon as possible: right away if the underlying wrapped stream is
  // already opened, or else as soon as it opens.
  //
  // These functions return a negative error code on failure.
  // Returning 0 means success so far, but negotiation is probably not
  // complete and will continue asynchronously.  In that case, the
  // exposed stream will open after successful negotiation and
  // verification, or an SE_CLOSE event will be raised if negotiation
  // fails.

  // StartSSLWithServer starts SSL negotiation with a server in
  // traditional mode. server_name specifies the expected server name
  // which the server's certificate needs to specify.
  virtual int StartSSLWithServer(const char* server_name) = 0;

  // StartSSLWithPeer starts negotiation in the special peer-to-peer
  // mode.
  // Generally, SetIdentity() and possibly SetServerRole() should have
  // been called before this.
  // SetPeerCertificate() must also be called. It may be called after
  // StartSSLWithPeer() but must be called before the underlying
  // stream opens.
  virtual int StartSSLWithPeer() = 0;

  // Specify the certificate that our peer is expected to use in
  // peer-to-peer mode. Only this certificate will be accepted during
  // SSL verification. The certificate is assumed to have been
  // obtained through some other secure channel (such as the XMPP
  // channel). (This could also specify the certificate authority that
  // will sign the peer's certificate.)
  // SSLStream takes ownership of the SSLCertificate object and will
  // free it when appropriate. Should be called no more than once on a
  // given SSLStream instance.
  virtual void SetPeerCertificate(SSLCertificate* cert) = 0;

  // Specify the digest of the certificate that our peer is expected to use in
  // peer-to-peer mode. Only this certificate will be accepted during
  // SSL verification. The certificate is assumed to have been
  // obtained through some other secure channel (such as the XMPP
  // channel). Unlike SetPeerCertificate(), this must specify the
  // terminal certificate, not just a CA.
  // SSLStream makes a copy of the digest value.
  virtual bool SetPeerCertificateDigest(const std::string& digest_alg,
                                        const unsigned char* digest_val,
                                        size_t digest_len) = 0;

  // If true, the server certificate need not match the configured
  // server_name, and in fact missing certificate authority and other
  // verification errors are ignored.
  bool ignore_bad_cert_;
};

}  // namespace talk_base

#endif  // TALK_BASE_SSLSTREAMADAPTER_H__