/*
 * Copyright (c)2013-2021 ZeroTier, Inc.
 *
 * Use of this software is governed by the Business Source License included
 * in the LICENSE.TXT file in the project's root directory.
 *
 * Change Date: 2026-01-01
 *
 * On the date above, in accordance with the Business Source License, use
 * of this software will be governed by version 2.0 of the Apache License.
 */
/****/

#ifndef ZT_TRUSTSTORE_HPP
#define ZT_TRUSTSTORE_HPP

#include "Certificate.hpp"
#include "Constants.hpp"
#include "Containers.hpp"
#include "Context.hpp"
#include "Fingerprint.hpp"
#include "Identity.hpp"
#include "Mutex.hpp"
#include "Peer.hpp"
#include "SHA512.hpp"
#include "SharedPtr.hpp"

namespace ZeroTier {

/**
 * Certificate store and chain validator.
 *
 * WARNING: SharedPtr<Entry> entries returned from a trust store are valid
 * only as long as the trust store exists. The trust store is a core object
 * that lives as long as a Node, so this isn't an issue in the core, but it
 * should be remembered when testing.
 *
 * This is because each Entry includes a reference to its parent's mutex and
 * is synchronized by this mutex so its fields are safe to access while the
 * parent trust store is being modified or synchronized.
 *
 * This also means entries can't be moved between TrustStore instances,
 * hence there are no methods for doing that. There's only one instance in a
 * node anyway.
 */
class TrustStore {
  public:
    /**
     * An entry in the node certificate trust store
     */
    class Entry {
        friend class SharedPtr<TrustStore::Entry>;
        friend class SharedPtr<const TrustStore::Entry>;
        friend class TrustStore;

      public:
        /**
         * @return Reference to held certificate
         */
        ZT_INLINE const Certificate &certificate() const noexcept { return m_certificate; }

        /**
         * Get the local trust for this certificate
         *
         * This value may be changed dynamically by calls to update().
         *
         * @return Local trust bit mask
         */
        ZT_INLINE unsigned int localTrust() const noexcept
        {
            RWMutex::RLock l(m_lock);
            return m_localTrust;
        }

        /**
         * Change the local trust of this entry
         *
         * @param lt New local trust bit mask
         */
        ZT_INLINE void setLocalTrust(const unsigned int lt) noexcept
        {
            RWMutex::Lock l(m_lock);
            m_localTrust = lt;
        }

        /**
         * Get the error code for this certificate
         *
         * @return Error or ZT_CERTIFICATE_ERROR_NONE if none
         */
        ZT_INLINE ZT_CertificateError error() const noexcept
        {
            RWMutex::RLock l(m_lock);
            return m_error;
        }

      private:
        Entry &operator=(const Entry &) { return *this; }

        ZT_INLINE Entry(RWMutex &l, const Certificate &cert, const unsigned int lt) noexcept : __refCount(0), m_lock(l), m_certificate(cert), m_localTrust(lt), m_error(ZT_CERTIFICATE_ERROR_NONE), m_subjectDeprecated(false), m_onTrustPath(false) {}

        std::atomic<int> __refCount;

        RWMutex &m_lock;
        const Certificate m_certificate;
        unsigned int m_localTrust;
        ZT_CertificateError m_error;
        bool m_subjectDeprecated;
        bool m_onTrustPath;
    };

    TrustStore();
    ~TrustStore();

    /**
     * Get certificate by certificate serial number
     *
     * Note that the error code should be checked. The certificate may be
     * rejected and may still be in the store unless the store has been
     * purged.
     *
     * @param serial SHA384 hash of certificate
     * @return Entry or empty/nil if not found
     */
    SharedPtr<Entry> get(const H384 &serial) const;

    /**
     * Get roots specified by root set certificates in the local store.
     *
     * If more than one certificate locally trusted as a root set specifies
     * the root, it will be returned once (as per Map behavior) but the latest
     * locator will be returned from among those available.
     *
     * @return Roots and the latest locator specified for each (if any)
     */
    Map<Identity, SharedPtr<const Locator>> roots();

    /**
     * @param includeRejectedCertificates If true, also include certificates with error codes
     * @return All certificates in asecending sort order by serial
     */
    Vector<SharedPtr<Entry>> all(bool includeRejectedCertificates) const;

    /**
     * Add a certificate
     *
     * A copy is made so it's fine if the original is freed after this call. If
     * the certificate already exists its local trust flags are updated.
     *
     * IMPORTANT: The caller MUST also call update() after calling add() one or
     * more times to actually add and revalidate certificates and their signature
     * chains.
     *
     * @param cert Certificate to add
     */
    void add(const Certificate &cert, unsigned int localTrust);

    /**
     * Queue a certificate to be deleted
     *
     * Actual delete does not happen until the next update().
     *
     * @param serial Serial of certificate to delete
     */
    void erase(const H384 &serial);

    /**
     * Validate all certificates and their certificate chains
     *
     * This also processes any certificates added with add() since the last call to update().
     *
     * @param clock Current time in milliseconds since epoch, or -1 to not check times on this pass
     * @param purge If non-NULL, purge rejected certificates and return them in this vector (vector should be empty)
     * @return True if there were changes
     */
    bool update(int64_t clock, Vector<SharedPtr<Entry>> *purge);

    /**
     * Create a compressed binary version of certificates and their local trust
     *
     * @return Binary compressed certificates and local trust info
     */
    Vector<uint8_t> save() const;

    /**
     * Decode a saved trust store
     *
     * Decoded certificates are added to the add queue, so update() must be
     * called after this to actually apply them.
     *
     * @param data Data to decode
     * @return Number of certificates or -1 if input is invalid
     */
    int load(const Vector<uint8_t> &data);

  private:
    Map<H384, SharedPtr<Entry>> m_bySerial;                                                // all certificates
    Map<Blob<ZT_CERTIFICATE_MAX_PUBLIC_KEY_SIZE>, SharedPtr<Entry>> m_bySubjectUniqueId;   // non-rejected certificates only
    Map<Fingerprint, Vector<SharedPtr<Entry>>> m_bySubjectIdentity;                        // non-rejected certificates only
    ForwardList<SharedPtr<Entry>> m_addQueue;
    ForwardList<H384> m_deleteQueue;
    RWMutex m_lock;
};

}   // namespace ZeroTier

#endif