Function validate_encrypted_frame

src/dpp/dave/codec_utils.cpp:373–414

}

bool validate_encrypted_frame(outbound_frame_processor& processor, array_view<uint8_t> frame)
{
	auto codec = processor.get_codec();
	if (codec != codec::cd_h264 && codec != codec::cd_h265) {
		return true;
	}

	constexpr size_t padding = nalu_short_start_sequence_size - 1;

	const auto& unencrypted_ranges = processor.get_unencrypted_ranges();

	// H264 and H265 ciphertexts cannot contain a 3 or 4 byte start code {0, 0, 1}
	// otherwise the packetizer gets confused
	// and the frame we get on the decryption side will be shifted and fail to decrypt
	size_t encrypted_section_start = 0;
	for (auto& range : unencrypted_ranges) {
		if (encrypted_section_start == range.offset) {
			encrypted_section_start += range.size;
			continue;
		}

		auto start = encrypted_section_start - std::min(encrypted_section_start, size_t{padding});
		auto end = std::min(range.offset + padding, frame.size());
		if (next_h26x_nalu_index(frame.data() + start, end - start)) {
			return false;
		}

		encrypted_section_start = range.offset + range.size;
	}

	if (encrypted_section_start == frame.size()) {
		return true;
	}

	auto start = encrypted_section_start - std::min(encrypted_section_start, size_t{padding});
	auto end = frame.size();
	if (next_h26x_nalu_index(frame.data() + start, end - start)) {
		return false;
	}

	return true;
}

}