gstreamer/ext/dtls/gstdtlssrtpdemux.c

/*
 * Copyright (c) 2014, Ericsson AB. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or other
 * materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */

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

#include "gstdtlssrtpdemux.h"

#define PACKET_IS_DTLS(b) (b > 0x13 && b < 0x40)
#define PACKET_IS_RTP(b) (b > 0x7f && b < 0xc0)

static GstStaticPadTemplate sink_template =
    GST_STATIC_PAD_TEMPLATE("sink",
        GST_PAD_SINK,
        GST_PAD_ALWAYS,
        GST_STATIC_CAPS_ANY
    );

static GstStaticPadTemplate rtp_src_template =
    GST_STATIC_PAD_TEMPLATE("rtp_src",
        GST_PAD_SRC,
        GST_PAD_ALWAYS,
        GST_STATIC_CAPS(
            "application/x-rtp;"
            "application/x-rtcp;"
            "application/x-srtp;"
            "application/x-srtcp")
    );

static GstStaticPadTemplate dtls_src_template =
    GST_STATIC_PAD_TEMPLATE("dtls_src",
        GST_PAD_SRC,
        GST_PAD_ALWAYS,
        GST_STATIC_CAPS("application/x-dtls")
    );

GST_DEBUG_CATEGORY_STATIC(er_er_dtls_srtp_demux_debug);
#define GST_CAT_DEFAULT er_er_dtls_srtp_demux_debug

#define gst_er_dtls_srtp_demux_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE(GstErDtlsSrtpDemux, gst_er_dtls_srtp_demux, GST_TYPE_ELEMENT,
    GST_DEBUG_CATEGORY_INIT(er_er_dtls_srtp_demux_debug, "erdtlssrtpdemux", 0, "Ericsson DTLS SRTP Demultiplexer"));

static GstFlowReturn sink_chain(GstPad *, GstObject *self, GstBuffer *);

static void gst_er_dtls_srtp_demux_class_init(GstErDtlsSrtpDemuxClass *klass)
{
    GstElementClass *element_class;

    element_class = (GstElementClass *) klass;

    gst_element_class_add_pad_template(element_class,
        gst_static_pad_template_get(&sink_template));
    gst_element_class_add_pad_template(element_class,
        gst_static_pad_template_get(&rtp_src_template));
    gst_element_class_add_pad_template(element_class,
        gst_static_pad_template_get(&dtls_src_template));

    gst_element_class_set_static_metadata(element_class,
        "DTLS SRTP Demultiplexer",
        "DTLS/SRTP/Demux",
        "Demultiplexes DTLS and SRTP packets",
        "Patrik Oldsberg patrik.oldsberg@ericsson.com");
}

static void gst_er_dtls_srtp_demux_init(GstErDtlsSrtpDemux *self)
{
    GstPad *sink;

    sink = gst_pad_new_from_static_template(&sink_template, "sink");
    self->rtp_src = gst_pad_new_from_static_template(&rtp_src_template, "rtp_src");
    self->dtls_src = gst_pad_new_from_static_template(&dtls_src_template, "dtls_src");
    g_return_if_fail(sink);
    g_return_if_fail(self->rtp_src);
    g_return_if_fail(self->dtls_src);

    gst_pad_set_chain_function(sink, GST_DEBUG_FUNCPTR(sink_chain));

    gst_element_add_pad(GST_ELEMENT(self), sink);
    gst_element_add_pad(GST_ELEMENT(self), self->rtp_src);
    gst_element_add_pad(GST_ELEMENT(self), self->dtls_src);
}

static GstFlowReturn sink_chain(GstPad *pad, GstObject *parent, GstBuffer *buffer)
{
    GstErDtlsSrtpDemux *self = GST_ER_DTLS_SRTP_DEMUX(parent);
    guint8 first_byte;

    if (gst_buffer_get_size(buffer) == 0) {
        GST_LOG_OBJECT(self, "received buffer with size 0");
        gst_buffer_unref(buffer);
        return GST_FLOW_OK;
    }

    if (gst_buffer_extract(buffer, 0, &first_byte, 1) != 1) {
        GST_WARNING_OBJECT(self, "could not extract first byte from buffer");
        gst_buffer_unref(buffer);
        return GST_FLOW_OK;
    }

    if (PACKET_IS_DTLS(first_byte)) {
        GST_LOG_OBJECT(self, "pushing dtls packet");

        return gst_pad_push(self->dtls_src, buffer);
    }

    if (PACKET_IS_RTP(first_byte)) {
        GST_LOG_OBJECT(self, "pushing rtp packet");

        return gst_pad_push(self->rtp_src, buffer);
    }

    GST_WARNING_OBJECT(self, "received invalid buffer: %x", first_byte);
    gst_buffer_unref(buffer);
    return GST_FLOW_OK;
}