agent_db.h

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/*
 * Copyright (c) 2013 Juniper Networks, Inc. All rights reserved.
 */
 
#ifndef vnsw_agent_db_hpp
#define vnsw_agent_db_hpp
 
#include <atomic>
#include <mutex>
#include <cmn/agent_cmn.h>
 
class Agent;
class AgentDBEntry;
class AgentDBTable;
struct AgentDBState;
class AgentSandesh;
class AgentSandeshArguments;
class AgentSandesh;
class ResourceManager;
typedef class boost::shared_ptr<AgentSandesh> AgentSandeshPtr;
 
// Refcount class for AgentDBEntry
template <class Derived>
class AgentRefCount {
public:
    friend void intrusive_ptr_add_ref(const Derived* p) {
        const AgentRefCount *entry = (const AgentRefCount *) (p);
        if (entry->refcount_.fetch_add(1) == 0) {
            p->SetRefState();
        }
    }
 
    friend void intrusive_ptr_release(const Derived* p) {
        const AgentRefCount *entry = (const AgentRefCount *) (p);
        if (entry->refcount_.fetch_sub(1) == 1) {
            p->ClearRefState();
        }
    }
 
    friend void intrusive_ptr_add_back_ref(const IntrusiveReferrer ref,
                                           const Derived* p) {
        const AgentRefCount *entry = (const AgentRefCount *) (p);
        std::scoped_lock lock(entry->back_ref_mutex_);
        entry->back_ref_set_.insert(ref);
    }
 
    friend void intrusive_ptr_del_back_ref(const IntrusiveReferrer ref,
                                           const Derived* p) {
        const AgentRefCount *entry = (const AgentRefCount *) (p);
        std::scoped_lock lock(entry->back_ref_mutex_);
        entry->back_ref_set_.erase(ref);
    }
 
    uint32_t GetRefCount() const {return refcount_;};
protected:
    AgentRefCount() {refcount_ = 0;}
    AgentRefCount(const AgentRefCount&) { refcount_ = 0; }
    AgentRefCount& operator=(const AgentRefCount&) { return *this; }
    virtual ~AgentRefCount() {assert(refcount_ == 0);};
    void swap(AgentRefCount&) {};
 
    mutable std::mutex back_ref_mutex_;
    mutable std::set<IntrusiveReferrer> back_ref_set_;
 
private:
    mutable std::atomic<uint32_t> refcount_;
};
 
// DBState for AgentDBEntry
struct AgentDBState : DBState {
    AgentDBState(const AgentDBEntry *entry) : DBState(), entry_(entry) { };
    const AgentDBEntry *entry_;
};
 
// VNSwitch DB Table Partition class
class AgentDBTablePartition: public DBTablePartition {
public:
    AgentDBTablePartition(DBTable *parent, int index) :
        DBTablePartition(parent, index) { };
    virtual ~AgentDBTablePartition() {};
    virtual void Add(DBEntry *entry);
    virtual void Remove(DBEntryBase *entry);
 
private:
    DISALLOW_COPY_AND_ASSIGN(AgentDBTablePartition);
};
 
// VNSwitch DB Entry Key base class. Defines additional operations on DBEntry
struct AgentKey : public DBRequestKey {
    typedef enum {
        // Add/Delete/Change a entry
        ADD_DEL_CHANGE,
        // Change an entry if its already present and not in deleted state
        // Its a no-op if entry is not present or is in deleted state
        RESYNC,
    } DBSubOperation;
 
    AgentKey() : DBRequestKey(), sub_op_(ADD_DEL_CHANGE) { };
    AgentKey(DBSubOperation sub_op) : DBRequestKey(), sub_op_(sub_op) { };
    virtual ~AgentKey() { };
 
    uint8_t sub_op_;
};
 
// VNSwitch DB Entry Data base class
struct AgentData : public DBRequestData {
    AgentData() : DBRequestData() { };
    virtual ~AgentData() { };
};
 
// VNSwitch DB Entry base class. Supports
// 1. Reference counting with boost Intrusive pointer
class AgentDBEntry : public DBEntry {
public:
    AgentDBEntry() : DBEntry() {};
    virtual ~AgentDBEntry() {};
    virtual uint32_t GetRefCount() const = 0;
 
    typedef boost::intrusive_ptr<AgentDBEntry> AgentDBEntyRef;
    void SetRefState() const;
    void ClearRefState() const;
    bool IsActive() const;
    DBState *GetAgentDBEntryState(int listener_id);
    const DBState *GetAgentDBEntryState(int listener_id) const;
 
    virtual void AllocateResources(ResourceManager *resource_manager);
    virtual void FreeResources(ResourceManager *resource_manager);
    virtual void PostAdd();
    virtual bool DBEntrySandesh(Sandesh *resp, std::string &name) const = 0;
private:
    friend class AgentDBTable;
    DISALLOW_COPY_AND_ASSIGN(AgentDBEntry);
};
 
// VNSwitch DB Table base class
class AgentDBTable : public DBTable {
public:
    static const int kPartitionCount = 1;
    AgentDBTable(DB *db, const std::string &name);
    AgentDBTable(DB *db, const std::string &name, bool del_on_zero_refcount);
    virtual ~AgentDBTable();
 
    virtual int PartitionCount() const { return kPartitionCount; }
    virtual void Input(DBTablePartition *root, DBClient *client,
                       DBRequest *req);
    virtual DBEntry *CfgAdd(DBRequest *req) {return NULL;};
    virtual bool Resync(DBEntry *entry, const DBRequest *req) {return false;};
 
    /*
     * Clear all entries on a table. Requires the table to have no listeners.
     * Used in process shutdown.
     */
    virtual void Clear();
 
    virtual bool IFNodeToReq(IFMapNode *node, DBRequest &req,
            const boost::uuids::uuid &uuid) {
        assert(0);
        return false;
    }
    virtual bool IFLinkToReq(IFMapLink *link, IFMapNode *node,
                             const std::string &peer_name, IFMapNode *peer,
                             DBRequest &req) {
        assert(0);
        return false;
    }
    virtual bool IFNodeToUuid(IFMapNode *node, boost::uuids::uuid &id);
 
    virtual DBTablePartition *AllocPartition(int index) {
        return new AgentDBTablePartition(this, index);
    };
    virtual void OnZeroRefcount(AgentDBEntry *e) {};
    virtual void NotifyEntry(DBEntryBase *entry);
 
    virtual AgentSandeshPtr GetAgentSandesh(const AgentSandeshArguments *args,
                                            const std::string &context) {
        return AgentSandeshPtr();
    }
 
    // Dummy notification
    void Notify(DBTablePartBase *partition, DBEntryBase *entry) {
    };
 
    DBTableBase::ListenerId GetRefListenerId() const {return ref_listener_id_;};
    AgentDBEntry *FindActiveEntry(const DBEntry *key);
    AgentDBEntry *FindActiveEntryNoLock(const DBEntry *key);
    AgentDBEntry *FindActiveEntry(const DBRequestKey *key);
    AgentDBEntry *FindActiveEntryNoLock(const DBRequestKey *key);
    AgentDBEntry *Find(const DBEntry *key, bool ret_del);
    AgentDBEntry *Find(const DBRequestKey *key, bool ret_del);
    virtual bool CanNotify(IFMapNode *dbe) {
        return true;
    }
    virtual void Process(DBRequest &req);
    virtual bool ProcessConfig(IFMapNode *node, DBRequest &req,
            const boost::uuids::uuid &u) {
        assert(0);
        return false;
    }
 
    void set_agent(Agent *agent) { agent_ = agent; }
    Agent *agent() const { return agent_; }
 
    void Flush();
    void reset_flush_walk_ref();
    SandeshTraceBufferPtr GetOperDBTraceBuf() const {return OperDBTraceBuf;}
private:
    AgentDBEntry *Find(const DBEntry *key);
    AgentDBEntry *Find(const DBRequestKey *key);
 
    DBTableBase::ListenerId ref_listener_id_;
    Agent *agent_;
    SandeshTraceBufferPtr OperDBTraceBuf;
    DBTable::DBTableWalkRef flush_walk_ref_;
    DISALLOW_COPY_AND_ASSIGN(AgentDBTable);
};
 
#define OPER_TRACE(obj, ...)\
do {\
   Oper##obj::TraceMsg(GetOperDBTraceBuf(), __FILE__, __LINE__, __VA_ARGS__);\
} while (false)
 
#define OPER_TRACE_ENTRY(obj, table, ...)\
do {\
   Oper##obj::TraceMsg(table->GetOperDBTraceBuf(),\
                       __FILE__, __LINE__, __VA_ARGS__);\
} while (false)
 
#endif // vnsw_agent_db_hpp