* #35924: added zrtp module build instructions
diff --git a/jni/libzrtp/src/libzrtpcpp/ZrtpUserCallback.h b/jni/libzrtp/src/libzrtpcpp/ZrtpUserCallback.h
new file mode 100644
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+++ b/jni/libzrtp/src/libzrtpcpp/ZrtpUserCallback.h
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+/*
+ Copyright (C) 2006-2008 Werner Dittmann
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _ZRTPUSERCALLBACK_H_
+#define _ZRTPUSERCALLBACK_H_
+
+/**
+ * @file ZrtpUserCallback.h
+ * @brief The ZRTP UserCallback class
+ *
+ * @ingroup GNU_ZRTP
+ * @{
+ */
+
+#include <stdint.h>
+#include <string>
+
+#include <libzrtpcpp/ZrtpCodes.h>
+
+/**
+ * Application callback methods.
+ *
+ * The ccRTP specific part of GNU ZRTP uses these callback methods
+ * to report ZRTP events to the application. This class implements a
+ * default behaviour for each callback method, usually just a return.
+ *
+ * An application may extend this class and overload methods
+ * to implement its own behaviour. The application must register its
+ * callback class using ZrtpQueue#setUserCallback().
+ *
+ * <b>CAVEAT</b><br/>
+ * All methods of the user callback class and classes that
+ * extend this class run in the context of the RTP thread. Thus it is
+ * of paramount importance to keep the execution time of the methods
+ * as short as possible.
+ *
+ * @author Werner Dittmann <Werner.Dittmann@t-online.de>
+ */
+
+class __EXPORT ZrtpUserCallback {
+
+ public:
+
+ /// Create the stadard user callback class.
+ ZrtpUserCallback() {}
+
+ virtual ~ZrtpUserCallback() {};
+
+ /**
+ * Inform user interface that security is active now.
+ *
+ * ZRTP calls this method if the sender and the receiver are
+ * in secure mode now.
+ *
+ * @param cipher
+ * Name and mode of cipher used to encrypt the SRTP stream
+ */
+ virtual void secureOn(std::string cipher) {
+ return;
+ }
+ /**
+ * Inform user interface that security is not active any more.
+ *
+ * ZRTP calls this method if either the sender or the receiver
+ * left secure mode.
+ *
+ */
+ virtual void secureOff() {
+ return;
+ }
+
+ /**
+ * Show the Short Authentication String (SAS) on user interface.
+ *
+ * ZRTP calls this method to display the SAS and inform about the SAS
+ * verification status. The user interface shall enable a SAS verfication
+ * button (or similar UI element). The user shall click on this UI
+ * element after he/she confirmed the SAS code with the partner.
+ *
+ * @param sas
+ * The string containing the SAS.
+ * @param verified
+ * If <code>verified</code> is true then SAS was verified by both
+ * parties during a previous call, otherwise it is set to false.
+ */
+ virtual void showSAS(std::string sas, bool verified) {
+ return;
+ }
+
+ /**
+ * Inform the user that ZRTP received "go clear" message from its peer.
+ *
+ * On receipt of a go clear message the user is requested to confirm
+ * a switch to unsecure (clear) modus. Until the user confirms ZRTP
+ * (and the underlying RTP) does not send any data.
+ */
+ virtual void confirmGoClear() {
+ return;
+ }
+
+ /**
+ * Show some information to user.
+ *
+ * ZRTP calls this method to display some information to the user.
+ * Along with the message ZRTP provides a severity indicator that
+ * defines: Info, Warning, Error, and Alert. Refer to the <code>
+ * MessageSeverity</code> enum in <code>ZrtpCodes.h</code>. The
+ * UI may use this indicator to highlight messages or alike.
+ *
+ * @param sev
+ * Severity of the message.
+ * @param subCode
+ * The subcode identifying the reason.
+ */
+ virtual void showMessage(GnuZrtpCodes::MessageSeverity sev, int32_t subCode) {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this if the negotiation failed.
+ *
+ * ZRTPQueue calls this method in case ZRTP negotiation failed. The
+ * parameters show the severity as well as some explanatory text.
+ * Refer to the <code>MessageSeverity</code> enum above.
+ *
+ * @param severity
+ * This defines the message's severity
+ * @param subCode
+ * The subcode identifying the reason.
+ */
+ virtual void zrtpNegotiationFailed(GnuZrtpCodes::MessageSeverity severity,
+ int32_t subCode) {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this method if the other side does not support ZRTP.
+ *
+ * If the other side does not answer the ZRTP <em>Hello</em> packets then
+ * ZRTP calls this method.
+ *
+ */
+ virtual void zrtpNotSuppOther() {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this method to inform about a PBX enrollment request.
+ *
+ * Please refer to chapter 8.3 ff to get more details about PBX enrollment
+ * and SAS relay.
+ *
+ * @param info
+ * Give some information to the user about the PBX requesting an
+ * enrollment.
+ *
+ */
+ virtual void zrtpAskEnrollment(GnuZrtpCodes::InfoEnrollment info) {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this method to inform about PBX enrollment result.
+ *
+ * Informs the use about the acceptance or denial of an PBX enrollment
+ * request
+ *
+ * @param info
+ * Give some information to the user about the result of an
+ * enrollment.
+ *
+ */
+ virtual void zrtpInformEnrollment(GnuZrtpCodes::InfoEnrollment info) {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this method to request a SAS signature.
+ *
+ * After ZRTP core was able to compute the Short Authentication String
+ * (SAS) it calls this method. The client may now use an approriate
+ * method to sign the SAS. The client may use
+ * setSignatureData() of ZrtpQueue to store the signature
+ * data an enable signature transmission to the other peer. Refer
+ * to chapter 8.2 of ZRTP specification.
+ *
+ * @param sasHash
+ * Pointer to the 32 byte SAS hash to be signed.
+ * @see ZrtpQueue#setSignatureData
+ *
+ */
+ virtual void signSAS(uint8_t* sasHash) {
+ return;
+ }
+
+ /**
+ * ZRTPQueue calls this method to request a SAS signature check.
+ *
+ * After ZRTP received a SAS signature in one of the Confirm packets it
+ * call this method. The client may use <code>getSignatureLength()</code>
+ * and <code>getSignatureData()</code>of ZrtpQueue to get the signature
+ * data and perform the signature check. Refer to chapter 8.2 of ZRTP
+ * specification.
+ *
+ * If the signature check fails the client may return false to ZRTP. In
+ * this case ZRTP signals an error to the other peer and terminates
+ * the ZRTP handshake.
+ *
+ * @param sasHash
+ * Pointer to the 32 byte SAS hash that was signed by the other peer.
+ * @return
+ * true if the signature was ok, false otherwise.
+ *
+ */
+ virtual bool checkSASSignature(uint8_t* sasHash) {
+ return true;
+ }
+};
+
+#endif