rtcp: update documentation (#666)

README.md

@@ -194,6 +194,7 @@ legend:
 * [RFC 4585](https://tools.ietf.org/html/rfc4585) - Extended RTP Profile for RTCP-Based Feedback
 * [RFC 4733](https://tools.ietf.org/html/rfc4733) - RTP Payload for DTMF Digits, Telephony Tones, and Teleph. Signals
 * [RFC 4961](https://tools.ietf.org/html/rfc4961) - Symmetric RTP / RTP Control Protocol (RTCP)
+* [RFC 5104](https://tools.ietf.org/html/rfc5104) - Codec Control Messages in AVPF
 * [RFC 5118](https://tools.ietf.org/html/rfc5118) - SIP Torture Test Messages for IPv6
 * [RFC 5245](https://tools.ietf.org/html/rfc5245) - Interactive Connectivity Establishment (ICE)
 * [RFC 5246](https://tools.ietf.org/html/rfc5246) - The TLS Protocol Version 1.2

include/re_rtp.h

@@ -206,8 +206,25 @@ struct sa;
 struct re_printf;
 struct rtp_sock;
 
+/**
+ * Defines the callback handler for received RTP packets
+ *
+ * @param src  Source network address
+ * @param hdr  RTP header
+ * @param mb   RTP payload
+ * @param arg  Handler argument
+ */
 typedef void (rtp_recv_h)(const struct sa *src, const struct rtp_header *hdr,
 			  struct mbuf *mb, void *arg);
+
+
+/**
+ * Defines the callback handler for received RTCP packets
+ *
+ * @param src  Source network address
+ * @param msg  RTCP packet
+ * @param arg  Handler argument
+ */
 typedef void (rtcp_recv_h)(const struct sa *src, struct rtcp_msg *msg,
 			   void *arg);
 

src/rtp/pkt.c

@@ -257,6 +257,7 @@ int rtcp_vencode(struct mbuf *mb, enum rtcp_type type, uint32_t count,
  * @param mb    Buffer to encode into
  * @param type  RTCP Packet type
  * @param count Packet-specific count
+ * @param ...   Variable arguments, type specific
  *
  * @return 0 for success, otherwise errorcode
  */

src/rtp/rtcp.c

@@ -103,6 +103,7 @@ int rtcp_send_pli(struct rtp_sock *rs, uint32_t fb_ssrc)
 			       rtp_sess_ssrc(rs), fb_ssrc, NULL, NULL);
 }
 
+
 static int encode_fir_rfc5104_fci(struct mbuf *mb, void *arg)
 {
 	struct fir_rfc5104 *fci = arg;
@@ -114,6 +115,7 @@ static int encode_fir_rfc5104_fci(struct mbuf *mb, void *arg)
 	return err;
 }
 
+
 /**
  * Send an RTCP Full INTRA-frame Request (FIR) packet according to RFC 5104
  *
@@ -131,6 +133,14 @@ int rtcp_send_fir_rfc5104(struct rtp_sock *rs, uint32_t ssrc, uint8_t fir_seqn)
 			       &encode_fir_rfc5104_fci, &fci);
 }
 
+
+/**
+ * Get the name of an RTCP type
+ *
+ * @param type RTCP type
+ *
+ * @return String with RTCP name
+ */
 const char *rtcp_type_name(enum rtcp_type type)
 {
 	switch (type) {
@@ -151,6 +161,13 @@ const char *rtcp_type_name(enum rtcp_type type)
 }
 
 
+/**
+ * Get the name of an RTCP SDES type
+ *
+ * @param sdes RTCP SDES type
+ *
+ * @return String with RTCP SDES name
+ */
 const char *rtcp_sdes_name(enum rtcp_sdes_type sdes)
 {
 	switch (sdes) {
@@ -321,6 +338,13 @@ int rtcp_msg_print(struct re_printf *pf, const struct rtcp_msg *msg)
 }
 
 
+/**
+ * Check if packet is RTCP packet, used for de-multiplexing
+ *
+ * @param mb Mbuffer with packet
+ *
+ * @return True if RTCP packet, otherwise false
+ */
 bool rtp_is_rtcp_packet(const struct mbuf *mb)
 {
 	uint8_t pt;