/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FS_CEPH_AUTH_H
#define _FS_CEPH_AUTH_H

#include <linux/ceph/types.h>
#include <linux/ceph/buffer.h>

/*
 * Abstract interface for communicating with the authenticate module.
 * There is some handshake that takes place between us and the monitor
 * to acquire the necessary keys.  These are used to generate an
 * 'authorizer' that we use when connecting to a service (mds, osd).
 */

struct ceph_auth_client;
struct ceph_msg;

struct ceph_authorizer {
        void (*destroy)(struct ceph_authorizer *);
};

struct ceph_auth_handshake {
        struct ceph_authorizer *authorizer;
        void *authorizer_buf;
        size_t authorizer_buf_len;
        void *authorizer_reply_buf;
        size_t authorizer_reply_buf_len;
        int (*sign_message)(struct ceph_auth_handshake *auth,
                            struct ceph_msg *msg);
        int (*check_message_signature)(struct ceph_auth_handshake *auth,
                                       struct ceph_msg *msg);
};

struct ceph_auth_client_ops {
        /*
         * true if we are authenticated and can connect to
         * services.
         */
        int (*is_authenticated)(struct ceph_auth_client *ac);

        /*
         * true if we should (re)authenticate, e.g., when our tickets
         * are getting old and crusty.
         */
        int (*should_authenticate)(struct ceph_auth_client *ac);

        /*
         * build requests and process replies during monitor
         * handshake.  if handle_reply returns -EAGAIN, we build
         * another request.
         */
        int (*build_request)(struct ceph_auth_client *ac, void *buf, void *end);
        int (*handle_reply)(struct ceph_auth_client *ac, u64 global_id,
                            void *buf, void *end, u8 *session_key,
                            int *session_key_len, u8 *con_secret,
                            int *con_secret_len);

        /*
         * Create authorizer for connecting to a service, and verify
         * the response to authenticate the service.
         */
        int (*create_authorizer)(struct ceph_auth_client *ac, int peer_type,
                                 struct ceph_auth_handshake *auth);
        /* ensure that an existing authorizer is up to date */
        int (*update_authorizer)(struct ceph_auth_client *ac, int peer_type,
                                 struct ceph_auth_handshake *auth);
        int (*add_authorizer_challenge)(struct ceph_auth_client *ac,
                                        struct ceph_authorizer *a,
                                        void *challenge_buf,
                                        int challenge_buf_len);
        int (*verify_authorizer_reply)(struct ceph_auth_client *ac,
                                       struct ceph_authorizer *a,
                                       void *reply, int reply_len,
                                       u8 *session_key, int *session_key_len,
                                       u8 *con_secret, int *con_secret_len);
        void (*invalidate_authorizer)(struct ceph_auth_client *ac,
                                      int peer_type);

        /* reset when we (re)connect to a monitor */
        void (*reset)(struct ceph_auth_client *ac);

        void (*destroy)(struct ceph_auth_client *ac);

        int (*sign_message)(struct ceph_auth_handshake *auth,
                            struct ceph_msg *msg);
        int (*check_message_signature)(struct ceph_auth_handshake *auth,
                                       struct ceph_msg *msg);
};

struct ceph_auth_client {
        u32 protocol;           /* CEPH_AUTH_* */
        void *private;          /* for use by protocol implementation */
        const struct ceph_auth_client_ops *ops;  /* null iff protocol==0 */

        bool negotiating;       /* true if negotiating protocol */
        const char *name;       /* entity name */
        u64 global_id;          /* our unique id in system */
        const struct ceph_crypto_key *key;     /* our secret key */
        unsigned want_keys;     /* which services we want */

        int preferred_mode;     /* CEPH_CON_MODE_* */
        int fallback_mode;      /* ditto */

        struct mutex mutex;
};

void ceph_auth_set_global_id(struct ceph_auth_client *ac, u64 global_id);

struct ceph_auth_client *ceph_auth_init(const char *name,
                                        const struct ceph_crypto_key *key,
                                        const int *con_modes);
extern void ceph_auth_destroy(struct ceph_auth_client *ac);

extern void ceph_auth_reset(struct ceph_auth_client *ac);

extern int ceph_auth_build_hello(struct ceph_auth_client *ac,
                                 void *buf, size_t len);
extern int ceph_handle_auth_reply(struct ceph_auth_client *ac,
                                  void *buf, size_t len,
                                  void *reply_buf, size_t reply_len);
int ceph_auth_entity_name_encode(const char *name, void **p, void *end);

extern int ceph_build_auth(struct ceph_auth_client *ac,
                    void *msg_buf, size_t msg_len);
extern int ceph_auth_is_authenticated(struct ceph_auth_client *ac);

int __ceph_auth_get_authorizer(struct ceph_auth_client *ac,
                               struct ceph_auth_handshake *auth,
                               int peer_type, bool force_new,
                               int *proto, int *pref_mode, int *fallb_mode);
void ceph_auth_destroy_authorizer(struct ceph_authorizer *a);
int ceph_auth_add_authorizer_challenge(struct ceph_auth_client *ac,
                                       struct ceph_authorizer *a,
                                       void *challenge_buf,
                                       int challenge_buf_len);
int ceph_auth_verify_authorizer_reply(struct ceph_auth_client *ac,
                                      struct ceph_authorizer *a,
                                      void *reply, int reply_len,
                                      u8 *session_key, int *session_key_len,
                                      u8 *con_secret, int *con_secret_len);
extern void ceph_auth_invalidate_authorizer(struct ceph_auth_client *ac,
                                            int peer_type);

static inline int ceph_auth_sign_message(struct ceph_auth_handshake *auth,
                                         struct ceph_msg *msg)
{
        if (auth->sign_message)
                return auth->sign_message(auth, msg);
        return 0;
}

static inline
int ceph_auth_check_message_signature(struct ceph_auth_handshake *auth,
                                      struct ceph_msg *msg)
{
        if (auth->check_message_signature)
                return auth->check_message_signature(auth, msg);
        return 0;
}

int ceph_auth_get_request(struct ceph_auth_client *ac, void *buf, int buf_len);
int ceph_auth_handle_reply_more(struct ceph_auth_client *ac, void *reply,
                                int reply_len, void *buf, int buf_len);
int ceph_auth_handle_reply_done(struct ceph_auth_client *ac,
                                u64 global_id, void *reply, int reply_len,
                                u8 *session_key, int *session_key_len,
                                u8 *con_secret, int *con_secret_len);
bool ceph_auth_handle_bad_method(struct ceph_auth_client *ac,
                                 int used_proto, int result,
                                 const int *allowed_protos, int proto_cnt,
                                 const int *allowed_modes, int mode_cnt);

int ceph_auth_get_authorizer(struct ceph_auth_client *ac,
                             struct ceph_auth_handshake *auth,
                             int peer_type, void *buf, int *buf_len);
int ceph_auth_handle_svc_reply_more(struct ceph_auth_client *ac,
                                    struct ceph_auth_handshake *auth,
                                    void *reply, int reply_len,
                                    void *buf, int *buf_len);
int ceph_auth_handle_svc_reply_done(struct ceph_auth_client *ac,
                                    struct ceph_auth_handshake *auth,
                                    void *reply, int reply_len,
                                    u8 *session_key, int *session_key_len,
                                    u8 *con_secret, int *con_secret_len);
bool ceph_auth_handle_bad_authorizer(struct ceph_auth_client *ac,
                                     int peer_type, int used_proto, int result,
                                     const int *allowed_protos, int proto_cnt,
                                     const int *allowed_modes, int mode_cnt);

#endif