Cas Client repo update.

-Parse EMM in Cas plugin
-Entitlement key rotation support
-Multi_content_license support

plugin/include/emm_parser.h

@@ -0,0 +1,49 @@
+// Copyright 2020 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine Master
+// License Agreement.
+
+#ifndef EMM_PARSER_H
+#define EMM_PARSER_H
+
+#include <memory>
+#include <vector>
+
+#include "cas_types.h"
+#include "media_cas.pb.h"
+
+namespace wvcas {
+
+using video_widevine::EmmPayload;
+
+class EmmParser {
+ public:
+  EmmParser(const EmmParser&) = delete;
+  EmmParser& operator=(const EmmParser&) = delete;
+  virtual ~EmmParser() = default;
+
+  // The EmmParser factory method.
+  // The methods validates the passed in |emm|. If validation is successful, it
+  // constructs and returns an EmmParser. Otherwise, nullptr is returned.
+  static std::unique_ptr<const EmmParser> Create(const CasEmm& emm);
+
+  // Accessor methods.
+  virtual uint64_t timestamp() const { return timestamp_; }
+  virtual std::string signature() const { return signature_; }
+  virtual EmmPayload emm_payload() const { return emm_payload_; };
+
+ protected:
+  // Called by the factory create and unit test.
+  EmmParser() = default;
+
+ private:
+  bool Parse(int start_index, const CasEmm& emm);
+
+  uint8_t version_;
+  uint64_t timestamp_;
+  EmmPayload emm_payload_;
+  std::string signature_;
+};
+
+}  // namespace wvcas
+
+#endif  // EMM_PARSER_H

plugin/src/emm_parser.cpp

@@ -0,0 +1,75 @@
+// Copyright 2020 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine Master
+// License Agreement.
+
+#include "emm_parser.h"
+
+#include "log.h"
+
+namespace wvcas {
+namespace {
+// ETSI ETR 289 specifies table ids 0x82 to 0x8F are for CA System private
+// usage, which are typically used by EMM, with one table id for each EMM type.
+constexpr uint16_t kSectionHeader = 0x82;
+constexpr size_t kSectionHeaderSize = 3;
+constexpr size_t kSectionHeaderWithPointerSize = 4;
+constexpr uint8_t kPointerFieldZero = 0x00;
+
+// Returns the possible starting index of EMM. -1 will be returned in case of
+// error. It assumes the pointer field will always set to 0, if present.
+int find_emm_start_index(const CasEmm& cas_emm) {
+  if (cas_emm.empty()) {
+    return -1;
+  }
+  // Case 1: Pointer field (always set to 0); section header; EMM.
+  if (cas_emm[0] == kPointerFieldZero) {
+    return kSectionHeaderWithPointerSize < cas_emm.size()
+               ? kSectionHeaderWithPointerSize
+               : -1;
+  }
+  // Case 2: Section header (3 bytes), EMM.
+  if (cas_emm[0] == kSectionHeader) {
+    return kSectionHeaderSize < cas_emm.size() ? kSectionHeaderSize : -1;
+  }
+  // Case 3: EMM.
+  return 0;
+}
+
+}  // namespace
+
+std::unique_ptr<const EmmParser> EmmParser::Create(const CasEmm& emm) {
+  auto parser = std::unique_ptr<EmmParser>(new EmmParser());
+  if (!parser->Parse(find_emm_start_index(emm), emm)) {
+    return nullptr;
+  }
+  return parser;
+}
+
+bool EmmParser::Parse(int start_index, const CasEmm& emm) {
+  if (start_index < 0) {
+    return false;
+  }
+
+  video_widevine::SignedEmmPayload signed_emm;
+  if (!signed_emm.ParseFromArray(emm.data() + start_index,
+                                 emm.size() - start_index)) {
+    LOGE("Failed to parse signed EMM.");
+    return false;
+  }
+
+  signature_ = signed_emm.signature();
+  if (signature_.empty()) {
+    LOGE("No signature in the EMM.");
+    return false;
+  }
+
+  if (!emm_payload_.ParseFromString(signed_emm.serialized_payload())) {
+    LOGE("Failed to parse EMM payload.");
+    return false;
+  }
+  timestamp_ = emm_payload_.timestamp_secs();
+
+  return true;
+}
+
+}  // namespace wvcas