From 2f1e77aeafec89a8a1cab6ef452bd37fcd462cd2 Mon Sep 17 00:00:00 2001
From: winlin <winlin@vip.126.com>
Date: Thu, 6 Aug 2020 17:18:45 +0800
Subject: [PATCH] RTC: Fix RTCP app bug. Add is_rtcp_app API.

---
 trunk/src/kernel/srs_kernel_rtc_rtcp.cpp | 30 +++++++++++++++++++++++-
 trunk/src/kernel/srs_kernel_rtc_rtcp.hpp |  6 ++---
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/trunk/src/kernel/srs_kernel_rtc_rtcp.cpp b/trunk/src/kernel/srs_kernel_rtc_rtcp.cpp
index ef51e4ff3..4984a4c3a 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtcp.cpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtcp.cpp
@@ -84,12 +84,32 @@ srs_error_t SrsRtcpCommon::encode(SrsBuffer *buffer)
 
 SrsRtcpApp::SrsRtcpApp():ssrc_(0)
 {
+    header_.padding = 0;
+    header_.type = SrsRtcpType_app;
+    header_.rc = 0;
+    header_.version = kRtcpVersion;
 }
 
 SrsRtcpApp::~SrsRtcpApp()
 {
 }
 
+bool SrsRtcpApp::is_rtcp_app(uint8_t *data, int nb_data)
+{
+    if (!data || nb_data <12) {
+        return false;
+    }
+
+    SrsRtcpHeader *header = (SrsRtcpHeader*)data;
+    if (header->version == kRtcpVersion
+            && header->type == SrsRtcpType_app
+            && ntohs(header->length) >= 2) {
+        return true;
+    }
+
+    return false;
+}
+
 uint8_t SrsRtcpApp::type() const
 {
     return SrsRtcpType_app;
@@ -147,8 +167,12 @@ srs_error_t SrsRtcpApp::set_payload(uint8_t* payload, int len)
         return srs_error_new(ERROR_RTC_RTCP, "invalid payload length %d", len);
     }
 
-    payload_len_ = len;
+    payload_len_ = (len + 3)/ 4 * 4;;
     memcpy(payload_, payload, len);
+    if (payload_len_ > len) {
+        memset(&payload_[len], 0, payload_len_ - len); //padding
+    }
+    header_.length = payload_len_/4 + 3 - 1;
 
     return srs_success;
 }
@@ -166,6 +190,10 @@ srs_error_t SrsRtcpApp::decode(SrsBuffer *buffer)
         return srs_error_wrap(err, "decode header");
     }
 
+    if (header_.type != SrsRtcpType_app || !buffer->require(8)) {
+        return srs_error_new(ERROR_RTC_RTCP, "not rtcp app");
+    }
+
     ssrc_ = buffer->read_4bytes();
     buffer->read_bytes((char *)name_, sizeof(name_));
 
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtcp.hpp b/trunk/src/kernel/srs_kernel_rtc_rtcp.hpp
index de311305b..fb00832d4 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtcp.hpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtcp.hpp
@@ -51,6 +51,7 @@ enum SrsRtcpType
 };
 
 // RTCP Header, @see http://tools.ietf.org/html/rfc3550#section-6.1
+// @remark The header must be 4 bytes, which align with the max field size 2B.
 struct SrsRtcpHeader
 {
 	uint16_t rc:5;
@@ -84,15 +85,14 @@ public:
 class SrsRtcpApp : public SrsRtcpCommon 
 {
 private:
-    SrsRtcpHeader header_;
     uint32_t ssrc_;
     uint8_t name_[4];
-    uint8_t payload_[kRtcpPacketSize];
-    int payload_len_;
 public:
     SrsRtcpApp();
     virtual ~SrsRtcpApp();
 
+    static bool is_rtcp_app(uint8_t *data, int nb_data);
+
     virtual uint8_t type() const;
     
     uint32_t get_ssrc() const;