rtp: Add support for RFC5104 PSFB FIR.

baresip · Jun 22, 2022 · a4896ad · a4896ad
1 parent 7bcf5e4
commit a4896ad
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Showing 3 changed files with 58 additions and 0 deletions.
diff --git a/include/re_rtp.h b/include/re_rtp.h
@@ -69,6 +69,7 @@ enum rtcp_rtpfb {
 enum rtcp_psfb {
 	RTCP_PSFB_PLI  = 1,   /**< Picture Loss Indication (PLI) */
 	RTCP_PSFB_SLI  = 2,   /**< Slice Loss Indication (SLI)   */
+	RTCP_PSFB_FIR  = 4,   /**< Full INTRA-frame Request (FIR) (RFC 5104) */
 	RTCP_PSFB_AFB  = 15,  /**< Application layer Feedback Messages */
 };
 
@@ -167,6 +168,10 @@ struct rtcp_msg {
 					uint16_t number;
 					uint8_t picid;
 				} *sliv;
+				struct fir_rfc5104 {
+					uint32_t ssrc;
+					uint8_t seq_n;
+				} *firv;
 				struct twcc {
 					uint16_t seq;
 					uint16_t count;
@@ -237,6 +242,7 @@ int   rtcp_send_app(struct rtp_sock *rs, const char name[4],
 int   rtcp_send_fir(struct rtp_sock *rs, uint32_t ssrc);
 int   rtcp_send_nack(struct rtp_sock *rs, uint16_t fsn, uint16_t blp);
 int   rtcp_send_pli(struct rtp_sock *rs, uint32_t fb_ssrc);
+int   rtcp_send_fir_rfc5104(struct rtp_sock *rs, uint32_t ssrc, uint8_t fir_seqn);
 int   rtcp_debug(struct re_printf *pf, const struct rtp_sock *rs);
 void *rtcp_sock(const struct rtp_sock *rs);
 int   rtcp_stats(struct rtp_sock *rs, uint32_t ssrc, struct rtcp_stats *stats);

diff --git a/src/rtp/fb.c b/src/rtp/fb.c
@@ -22,6 +22,7 @@
 
 enum {
 	GNACK_SIZE = 4,
+	FIR_SIZE = 8,
 	SLI_SIZE   = 4
 };
 
@@ -253,6 +254,22 @@ int rtcp_psfb_decode(struct mbuf *mb, struct rtcp_msg *msg)
 		mbuf_advance(mb, sz);
 		break;
 
+	case RTCP_PSFB_FIR:
+		msg->r.fb.n /= 2u; /* each FCI entry size is 2 32-bit words */
+		sz = msg->r.fb.n * sizeof(*msg->r.fb.fci.firv);
+		msg->r.fb.fci.firv = mem_alloc(sz, NULL);
+		if (!msg->r.fb.fci.firv)
+			return ENOMEM;
+
+		if (mbuf_get_left(mb) < msg->r.fb.n * FIR_SIZE)
+			return EBADMSG;
+		for (i=0; i<msg->r.fb.n; i++) {
+			msg->r.fb.fci.firv[i].ssrc = ntohl(mbuf_read_u32(mb));
+			msg->r.fb.fci.firv[i].seq_n = mbuf_read_u8(mb);
+			mbuf_advance(mb, 3);
+		}
+		break;
+
 	default:
 		DEBUG_NOTICE("unknown PSFB fmt %d\n", msg->hdr.count);
 		break;

diff --git a/src/rtp/rtcp.c b/src/rtp/rtcp.c
@@ -103,6 +103,33 @@ 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;
+	int err = mbuf_write_u32(mb, htonl(fci->ssrc));
+	err |= mbuf_write_u8(mb, fci->seq_n);
+	err |= mbuf_write_u8(mb, 0);
+	err |= mbuf_write_u8(mb, 0);
+	err |= mbuf_write_u8(mb, 0);
+	return err;
+}
+
+/**
+ * Send an RTCP Full INTRA-frame Request (FIR) packet according to RFC 5104
+ *
+ * @param rs       RTP Socket
+ * @param ssrc     SSRC of the target encoder
+ * @param fir_seqn FIR sequence number
+ *
+ * @return 0 for success, otherwise errorcode
+ */
+int rtcp_send_fir_rfc5104(struct rtp_sock *rs, uint32_t ssrc, uint8_t fir_seqn)
+{
+	struct fir_rfc5104 fci = { ssrc, fir_seqn };
+	return rtcp_quick_send(rs, RTCP_PSFB, RTCP_PSFB_FIR,
+			       rtp_sess_ssrc(rs), (uint32_t)0u,
+			       &encode_fir_rfc5104_fci, &fci);
+}
 
 const char *rtcp_type_name(enum rtcp_type type)
 {
@@ -272,6 +299,14 @@ int rtcp_msg_print(struct re_printf *pf, const struct rtcp_msg *msg)
 			err |= re_hprintf(pf, " AFB %u bytes",
 					  msg->r.fb.n * 4);
 		}
+		else if (msg->hdr.count == RTCP_PSFB_FIR) {
+			err |= re_hprintf(pf, " FIR (RFC5104)");
+			for (i=0; i<msg->r.fb.n; i++) {
+				err |= re_hprintf(pf, " {ssrc=%08x seq_n=%02x}",
+						  msg->r.fb.fci.firv[i].ssrc,
+						  msg->r.fb.fci.firv[i].seq_n);
+			}
+		}
 		break;
 
 	default: