From d21ce3d27d3300ecd5e000130f00958c7abf36ae Mon Sep 17 00:00:00 2001
From: Alexey Khit <alexey.khit@gmail.com>
Date: Fri, 3 Feb 2023 12:10:54 +0300
Subject: [PATCH] Jump over wrong packets from RTSP

---
 cmd/rtsp/rtsp.go |  2 ++
 pkg/rtsp/conn.go | 65 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 53 insertions(+), 14 deletions(-)

diff --git a/cmd/rtsp/rtsp.go b/cmd/rtsp/rtsp.go
index 1951d0e9..ce9a723b 100644
--- a/cmd/rtsp/rtsp.go
+++ b/cmd/rtsp/rtsp.go
@@ -112,6 +112,8 @@ func rtspHandler(url string) (streamer.Producer, error) {
 				log.Trace().Msgf("[rtsp] client request:\n%s", msg)
 			case *tcp.Response:
 				log.Trace().Msgf("[rtsp] client response:\n%s", msg)
+			case string:
+				log.Trace().Msgf("[rtsp] client msg: %s", msg)
 			}
 		})
 	}
diff --git a/pkg/rtsp/conn.go b/pkg/rtsp/conn.go
index 39523ca6..bc9fe734 100644
--- a/pkg/rtsp/conn.go
+++ b/pkg/rtsp/conn.go
@@ -743,6 +743,9 @@ func (c *Conn) Handle() (err error) {
 			return
 		}
 
+		var channelID byte
+		var size uint16
+
 		if buf4[0] != '$' {
 			switch string(buf4) {
 			case "RTSP":
@@ -751,26 +754,62 @@ func (c *Conn) Handle() (err error) {
 					return
 				}
 				c.Fire(res)
+				continue
+
 			case "OPTI", "TEAR", "DESC", "SETU", "PLAY", "PAUS", "RECO", "ANNO", "GET_", "SET_":
 				var req *tcp.Request
 				if req, err = tcp.ReadRequest(c.reader); err != nil {
 					return
 				}
 				c.Fire(req)
+				continue
+
 			default:
-				return fmt.Errorf("RTSP wrong input")
+				for i := 0; ; i++ {
+					// search next start symbol
+					if _, err = c.reader.ReadBytes('$'); err != nil {
+						return err
+					}
+
+					if channelID, err = c.reader.ReadByte(); err != nil {
+						return err
+					}
+
+					// check if channel ID exists
+					if c.channels[channelID] == nil {
+						continue
+					}
+
+					buf4 = make([]byte, 2)
+					if _, err = io.ReadFull(c.reader, buf4); err != nil {
+						return err
+					}
+
+					// check if size good for RTP
+					size = binary.BigEndian.Uint16(buf4)
+					if size <= 1500 {
+						break
+					}
+
+					// 10 tries to find good packet
+					if i >= 10 {
+						return fmt.Errorf("RTSP wrong input")
+					}
+				}
+
+				c.Fire("RTSP wrong input")
 			}
-			continue
-		}
+		} else {
+			// hope that the odd channels are always RTCP
+			channelID = buf4[1]
 
-		// hope that the odd channels are always RTCP
-		channelID := buf4[1]
+			// get data size
+			size = binary.BigEndian.Uint16(buf4[2:])
 
-		// get data size
-		size := int(binary.BigEndian.Uint16(buf4[2:]))
-
-		if _, err = c.reader.Discard(4); err != nil {
-			return
+			// skip 4 bytes from c.reader.Peek
+			if _, err = c.reader.Discard(4); err != nil {
+				return
+			}
 		}
 
 		// init memory for data
@@ -779,7 +818,7 @@ func (c *Conn) Handle() (err error) {
 			return
 		}
 
-		c.receive += size
+		c.receive += int(size)
 
 		if channelID&1 == 0 {
 			packet := &rtp.Packet{}
@@ -790,10 +829,8 @@ func (c *Conn) Handle() (err error) {
 			track := c.channels[channelID]
 			if track != nil {
 				_ = track.WriteRTP(packet)
-				//return fmt.Errorf("wrong channelID: %d", channelID)
 			} else {
-				continue // TODO: maybe fix this
-				//panic("wrong channelID")
+				c.Fire("wrong channelID: " + strconv.Itoa(int(channelID)))
 			}
 		} else {
 			msg := &RTCP{Channel: channelID}