Add RTP support (#530)

This commit adds support for the Real-time Transport Protocol (RTP) as
defined in RFC 3550. Some tests have also been added to ensure that the
RTP PDU class functionality is working as expected.

Signed-off-by: James Raphael Tiovalen <jamestiotio@gmail.com>

include/tins/pdu.h

@@ -181,6 +181,7 @@ public:
         MPLS,
         DOT11_CONTROL_TA,
         VXLAN,
+        RTP,
         UNKNOWN = 999,
         USER_DEFINED_PDU = 1000
     };

include/tins/rtp.h

@@ -0,0 +1,328 @@
+#ifndef TINS_RTP_H
+#define TINS_RTP_H
+
+#include <tins/endianness.h>
+#include <tins/pdu.h>
+#include <tins/pdu_option.h>
+#include <tins/small_uint.h>
+
+namespace Tins {
+
+/**
+ * \class RTP
+ * \brief Represents a RTP PDU.
+ *
+ * This class represents a RTP PDU.
+ *
+ * \sa RawPDU
+ */
+class TINS_API RTP : public PDU {
+public:
+    /**
+     * \brief This PDU's flag.
+     */
+    static const PDU::PDUType pdu_flag = PDU::RTP;
+
+    /**
+     * The type used to store CSRC identifiers.
+     */
+    typedef std::vector<uint32_t> csrc_ids_type;
+
+    /**
+     * The type used to store extension header data.
+     */
+    typedef std::vector<uint32_t> extension_header_data_type;
+
+    /**
+     * Default constructor.
+     */
+    RTP();
+
+    /**
+     * \brief Constructs a RTP object from a buffer.
+     *
+     * \param data The buffer from which this PDU will be constructed.
+     * \param size The size of the data buffer.
+     */
+    RTP(const uint8_t* data, uint32_t size);
+
+    /**
+     * \brief Getter for the version.
+     */
+    small_uint<2> version() const { return header_.version; }
+
+    /**
+     * \brief Getter for the padding bit.
+     */
+    small_uint<1> padding_bit() const { return header_.padding; }
+
+    /**
+     * \brief Getter for the extension bit.
+     */
+    small_uint<1> extension_bit() const { return header_.extension; }
+
+    /**
+     * \brief Getter for the CSRC count.
+     */
+    small_uint<4> csrc_count() const { return header_.csrc_count; }
+
+    /**
+     * \brief Getter for the marker bit.
+     */
+    small_uint<1> marker_bit() const { return header_.marker; }
+
+    /**
+     * \brief Getter for the payload type.
+     */
+    small_uint<7> payload_type() const { return header_.payload_type; }
+
+    /**
+     * \brief Getter for the sequence number.
+     */
+    uint16_t sequence_number() const { return Endian::be_to_host(header_.seq_num); }
+
+    /**
+     * \brief Getter for the timestamp.
+     */
+    uint32_t timestamp() const { return Endian::be_to_host(header_.timestamp); }
+
+    /**
+     * \brief Getter for the SSRC identifier.
+     */
+    uint32_t ssrc_id() const { return Endian::be_to_host(header_.ssrc_id); }
+
+    /**
+     * \brief Getter for the CSRC identifiers.
+     */
+    const csrc_ids_type& csrc_ids() const {
+        return csrc_ids_;
+    }
+
+    /**
+     * \brief Getter for the padding size.
+     */
+    uint8_t padding_size() const { return padding_size_; }
+
+    /**
+     * \brief Getter for the extension header profile.
+     */
+    uint16_t extension_profile() const { return Endian::be_to_host(ext_header_.profile); }
+
+    /**
+     * \brief Getter for the extension header length.
+     */
+    uint16_t extension_length() const { return Endian::be_to_host(ext_header_.length); }
+
+    /**
+     * \brief Getter for the extension header data.
+     */
+    const extension_header_data_type& extension_data() const {
+        return ext_data_;
+    }
+
+    /**
+     * \brief Setter for the version.
+     * \param version The new version.
+     */
+    void version(small_uint<2> version) { header_.version = version; }
+
+    /**
+     * \brief Setter for the extension bit.
+     * \param extension The new extension bit.
+     */
+    void extension_bit(small_uint<1> extension) { header_.extension = extension; }
+
+    /**
+     * \brief Setter for the marker bit.
+     * \param marker The new marker bit.
+     */
+    void marker_bit(small_uint<1> marker) { header_.marker = marker; }
+
+    /**
+     * \brief Setter for the payload type.
+     * \param payload_type The new payload type.
+     */
+    void payload_type(small_uint<7> payload_type) { header_.payload_type = payload_type; }
+
+    /**
+     * \brief Setter for the sequence number.
+     * \param seq_num The new sequence number.
+     */
+    void sequence_number(uint16_t seq_num) { header_.seq_num = Endian::host_to_be(seq_num); }
+
+    /**
+     * \brief Setter for the timestamp.
+     * \param timestamp The new timestamp.
+     */
+    void timestamp(uint32_t timestamp) { header_.timestamp = Endian::host_to_be(timestamp); }
+
+    /**
+     * \brief Setter for the SSRC identifier.
+     * \param ssrc_id The new SSRC identifier.
+     */
+    void ssrc_id(uint32_t ssrc_id) { header_.ssrc_id = Endian::host_to_be(ssrc_id); }
+
+    /**
+     * \brief Setter for the padding size.
+     * \param size The new padding size.
+     */
+    void padding_size(uint8_t size) {
+        padding_bit(size > 0);
+        padding_size_ = size;
+    }
+
+    /**
+     * \brief Setter for the extension header profile.
+     * \param profile The new extension header profile.
+     */
+    void extension_profile(uint16_t profile) { ext_header_.profile = Endian::host_to_be(profile); }
+
+    /**
+     * \brief Adds a word of extension header data.
+     *
+     * The word is added after the last word of extension header data.
+     *
+     * \param value The value of the extension header data to be added.
+     */
+    void add_extension_data(const uint32_t value);
+
+    /**
+     * \brief Removes a word of extension header data.
+     *
+     * If there are multiple words of extension header data of the given value,
+     * only the first one will be removed.
+     *
+     * \param value The value of the extension header data to be removed.
+     * \return true if the extension header data was removed, false otherwise.
+     */
+    bool remove_extension_data(const uint32_t value);
+
+    /**
+     * \brief Searches for extension header data that matches the given value.
+     * \param value The extension header data to be searched.
+     * \return true if the extension header data was found, false otherwise.
+     */
+    bool search_extension_data(const uint32_t value);
+
+    /**
+     * \brief Adds a CSRC identifier.
+     *
+     * The CSRC identifier is added after the last CSRC identifier in the extension
+     * header.
+     *
+     * \param csrc_id The CSRC identifier to be added
+     */
+    void add_csrc_id(const uint32_t csrc_id);
+
+    /**
+     * \brief Removes a CSRC identifier.
+     *
+     * If there are multiple CSRC identifiers of the given value, only the first one
+     * will be removed.
+     *
+     * \param value The value of the CSRC identifier to be removed.
+     * \return true if the CSRC identifier was removed, false otherwise.
+     */
+    bool remove_csrc_id(const uint32_t value);
+
+    /**
+     * \brief Searches for a CSRC identifier that matches the given value.
+     * \param value The CSRC identifier to be searched.
+     * \return true if the CSRC identifier was found, false otherwise.
+     */
+    bool search_csrc_id(const uint32_t value);
+
+    /**
+     * \brief Returns the RTP packet's header length.
+     *
+     * This method overrides PDU::header_size.
+     *
+     * \return An uint32_t with the header's size.
+     * \sa PDU::header_size
+     */
+    uint32_t header_size() const;
+
+    /**
+     * \brief Returns the RTP packet's trailer length.
+     *
+     * This method overrides PDU::trailer_size.
+     *
+     * \return An uint32_t with the trailer's size.
+     * \sa PDU::trailer_size
+     */
+    uint32_t trailer_size() const { return static_cast<uint32_t>(padding_size_); }
+
+    /**
+     * \brief Getter for the PDU's type.
+     * \sa PDU::pdu_type
+     */
+    PDUType pdu_type() const { return pdu_flag; }
+
+    /**
+     * \sa PDU::clone
+     */
+    RTP *clone() const { return new RTP(*this); }
+
+private:
+    TINS_BEGIN_PACK
+    struct rtp_header {
+    #if TINS_IS_BIG_ENDIAN
+        uint16_t version:2,
+                 padding:1,
+                 extension:1,
+                 csrc_count:4,
+                 marker:1,
+                 payload_type:7;
+    #elif TINS_IS_LITTLE_ENDIAN
+        uint16_t csrc_count:4,
+                 extension:1,
+                 padding:1,
+                 version:2,
+                 payload_type:7,
+                 marker:1;
+    #endif
+        uint16_t seq_num;
+        uint32_t timestamp;
+        uint32_t ssrc_id;
+    } TINS_END_PACK;
+
+    TINS_BEGIN_PACK
+    struct rtp_extension_header {
+        uint16_t profile;
+        uint16_t length;
+    } TINS_END_PACK;
+
+    void write_serialization(uint8_t* buffer, uint32_t size);
+    csrc_ids_type::const_iterator search_csrc_id_iterator(const uint32_t csrc_id) const;
+    csrc_ids_type::iterator search_csrc_id_iterator(const uint32_t csrc_id);
+    extension_header_data_type::const_iterator search_extension_data_iterator(const uint32_t data) const;
+    extension_header_data_type::iterator search_extension_data_iterator(const uint32_t data);
+
+    /**
+     * \brief Setter for the padding bit.
+     * \param padding The new padding bit.
+     */
+    void padding_bit(small_uint<1> padding) { header_.padding = padding; }
+
+    /**
+     * \brief Setter for the CSRC count. Hidden from the public interface.
+     * \param csrc_count The new CSRC count.
+     */
+    void csrc_count(small_uint<4> csrc_count) { header_.csrc_count = csrc_count; }
+
+    /**
+     * \brief Setter for the extension header length. Hidden from the public interface.
+     * \param length The new extension header length.
+     */
+    void extension_length(uint16_t length) { ext_header_.length = Endian::host_to_be(length); }
+
+    rtp_header header_;
+    csrc_ids_type csrc_ids_;
+    rtp_extension_header ext_header_;
+    extension_header_data_type ext_data_;
+    uint8_t padding_size_;
+};
+
+} // Tins
+
+#endif // TINS_RTP_H

include/tins/tins.h

@@ -80,5 +80,6 @@
 #include <tins/ip_reassembler.h>
 #include <tins/pdu_iterator.h>
 #include <tins/vxlan.h>
+#include <tins/rtp.h>
 
 #endif // TINS_TINS_H