/* SPDX-License-Identifier: GPL-2.0 */
/*
 * linux/include/linux/lockd/lockd.h
 *
 * General-purpose lockd include file.
 *
 * Copyright (C) 1996 Olaf Kirch <okir@monad.swb.de>
 */

#ifndef LINUX_LOCKD_LOCKD_H
#define LINUX_LOCKD_LOCKD_H

/* XXX: a lot of this should really be under fs/lockd. */

#include <linux/exportfs.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <net/ipv6.h>
#include <linux/fs.h>
#include <linux/kref.h>
#include <linux/refcount.h>
#include <linux/utsname.h>
#include <linux/lockd/bind.h>
#include <linux/lockd/xdr.h>
#ifdef CONFIG_LOCKD_V4
#include <linux/lockd/xdr4.h>
#endif
#include <linux/lockd/debug.h>
#include <linux/sunrpc/svc.h>

/*
 * Version string
 */
#define LOCKD_VERSION           "0.5"

/*
 * Default timeout for RPC calls (seconds)
 */
#define LOCKD_DFLT_TIMEO        10

/*
 * Lockd host handle (used both by the client and server personality).
 */
struct nlm_host {
        struct hlist_node       h_hash;         /* doubly linked list */
        struct sockaddr_storage h_addr;         /* peer address */
        size_t                  h_addrlen;
        struct sockaddr_storage h_srcaddr;      /* our address (optional) */
        size_t                  h_srcaddrlen;
        struct rpc_clnt         *h_rpcclnt;     /* RPC client to talk to peer */
        char                    *h_name;                /* remote hostname */
        u32                     h_version;      /* interface version */
        unsigned short          h_proto;        /* transport proto */
        unsigned short          h_reclaiming : 1,
                                h_server     : 1, /* server side, not client side */
                                h_noresvport : 1,
                                h_inuse      : 1;
        wait_queue_head_t       h_gracewait;    /* wait while reclaiming */
        struct rw_semaphore     h_rwsem;        /* Reboot recovery lock */
        u32                     h_state;        /* pseudo-state counter */
        u32                     h_nsmstate;     /* true remote NSM state */
        u32                     h_pidcount;     /* Pseudopids */
        refcount_t              h_count;        /* reference count */
        struct mutex            h_mutex;        /* mutex for pmap binding */
        unsigned long           h_nextrebind;   /* next portmap call */
        unsigned long           h_expires;      /* eligible for GC */
        struct list_head        h_lockowners;   /* Lockowners for the client */
        spinlock_t              h_lock;
        struct list_head        h_granted;      /* Locks in GRANTED state */
        struct list_head        h_reclaim;      /* Locks in RECLAIM state */
        struct nsm_handle       *h_nsmhandle;   /* NSM status handle */
        char                    *h_addrbuf;     /* address eyecatcher */
        struct net              *net;           /* host net */
        const struct cred       *h_cred;
        char                    nodename[UNX_MAXNODENAME + 1];
        const struct nlmclnt_operations *h_nlmclnt_ops; /* Callback ops for NLM users */
};

/*
 * The largest string sm_addrbuf should hold is a full-size IPv6 address
 * (no "::" anywhere) with a scope ID.  The buffer size is computed to
 * hold eight groups of colon-separated four-hex-digit numbers, a
 * percent sign, a scope id (at most 32 bits, in decimal), and NUL.
 */
#define NSM_ADDRBUF             ((8 * 4 + 7) + (1 + 10) + 1)

struct nsm_handle {
        struct list_head        sm_link;
        refcount_t              sm_count;
        char                    *sm_mon_name;
        char                    *sm_name;
        struct sockaddr_storage sm_addr;
        size_t                  sm_addrlen;
        unsigned int            sm_monitored : 1,
                                sm_sticky : 1;  /* don't unmonitor */
        struct nsm_private      sm_priv;
        char                    sm_addrbuf[NSM_ADDRBUF];
};

/*
 * Rigorous type checking on sockaddr type conversions
 */
static inline struct sockaddr *nlm_addr(const struct nlm_host *host)
{
        return (struct sockaddr *)&host->h_addr;
}

static inline struct sockaddr *nlm_srcaddr(const struct nlm_host *host)
{
        return (struct sockaddr *)&host->h_srcaddr;
}

/*
 * Map an fl_owner_t into a unique 32-bit "pid"
 */
struct nlm_lockowner {
        struct list_head list;
        refcount_t count;

        struct nlm_host *host;
        fl_owner_t owner;
        uint32_t pid;
};

/*
 * This is the representation of a blocked client lock.
 */
struct nlm_wait {
        struct list_head        b_list;         /* linked list */
        wait_queue_head_t       b_wait;         /* where to wait on */
        struct nlm_host         *b_host;
        struct file_lock        *b_lock;        /* local file lock */
        __be32                  b_status;       /* grant callback status */
};

/*
 * Memory chunk for NLM client RPC request.
 */
#define NLMCLNT_OHSIZE          ((__NEW_UTS_LEN) + 10u)
struct nlm_rqst {
        refcount_t              a_count;
        unsigned int            a_flags;        /* initial RPC task flags */
        struct nlm_host *       a_host;         /* host handle */
        struct nlm_args         a_args;         /* arguments */
        struct nlm_res          a_res;          /* result */
        struct nlm_block *      a_block;
        unsigned int            a_retries;      /* Retry count */
        u8                      a_owner[NLMCLNT_OHSIZE];
        void *  a_callback_data; /* sent to nlmclnt_operations callbacks */
};

/*
 * This struct describes a file held open by lockd on behalf of
 * an NFS client.
 */
struct nlm_file {
        struct hlist_node       f_list;         /* linked list */
        struct nfs_fh           f_handle;       /* NFS file handle */
        struct file *           f_file[2];      /* VFS file pointers,
                                                   indexed by O_ flags */
        struct nlm_share *      f_shares;       /* DOS shares */
        struct list_head        f_blocks;       /* blocked locks */
        unsigned int            f_locks;        /* guesstimate # of locks */
        unsigned int            f_count;        /* reference count */
        struct mutex            f_mutex;        /* avoid concurrent access */
};

/*
 * This is a server block (i.e. a lock requested by some client which
 * couldn't be granted because of a conflicting lock).
 */
#define NLM_NEVER               (~(unsigned long) 0)
/* timeout on non-blocking call: */
#define NLM_TIMEOUT             (7 * HZ)

struct nlm_block {
        struct kref             b_count;        /* Reference count */
        struct list_head        b_list;         /* linked list of all blocks */
        struct list_head        b_flist;        /* linked list (per file) */
        struct nlm_rqst *       b_call;         /* RPC args & callback info */
        struct svc_serv *       b_daemon;       /* NLM service */
        struct nlm_host *       b_host;         /* host handle for RPC clnt */
        unsigned long           b_when;         /* next re-xmit */
        unsigned int            b_id;           /* block id */
        unsigned char           b_granted;      /* VFS granted lock */
        struct nlm_file *       b_file;         /* file in question */
        struct cache_req *      b_cache_req;    /* deferred request handling */
        struct cache_deferred_req * b_deferred_req;
        unsigned int            b_flags;        /* block flags */
#define B_QUEUED                1       /* lock queued */
#define B_GOT_CALLBACK          2       /* got lock or conflicting lock */
#define B_TIMED_OUT             4       /* filesystem too slow to respond */
};

/*
 * Global variables
 */
extern const struct rpc_program nlm_program;
extern const struct svc_procedure nlmsvc_procedures[24];
#ifdef CONFIG_LOCKD_V4
extern const struct svc_procedure nlmsvc_procedures4[24];
#endif
extern int                      nlmsvc_grace_period;
extern unsigned long            nlm_timeout;
extern bool                     nsm_use_hostnames;
extern u32                      nsm_local_state;

extern struct timer_list        nlmsvc_retry;

/*
 * Lockd client functions
 */
struct nlm_rqst * nlm_alloc_call(struct nlm_host *host);
int               nlm_async_call(struct nlm_rqst *, u32, const struct rpc_call_ops *);
int               nlm_async_reply(struct nlm_rqst *, u32, const struct rpc_call_ops *);
void              nlmclnt_release_call(struct nlm_rqst *);
void              nlmclnt_prepare_block(struct nlm_wait *block, struct nlm_host *host,
                                        struct file_lock *fl);
void              nlmclnt_queue_block(struct nlm_wait *block);
__be32            nlmclnt_dequeue_block(struct nlm_wait *block);
int               nlmclnt_wait(struct nlm_wait *block, struct nlm_rqst *req, long timeout);
__be32            nlmclnt_grant(const struct sockaddr *addr,
                                const struct nlm_lock *lock);
void              nlmclnt_recovery(struct nlm_host *);
int               nlmclnt_reclaim(struct nlm_host *, struct file_lock *,
                                  struct nlm_rqst *);
void              nlmclnt_next_cookie(struct nlm_cookie *);

/*
 * Host cache
 */
struct nlm_host  *nlmclnt_lookup_host(const struct sockaddr *sap,
                                        const size_t salen,
                                        const unsigned short protocol,
                                        const u32 version,
                                        const char *hostname,
                                        int noresvport,
                                        struct net *net,
                                        const struct cred *cred);
void              nlmclnt_release_host(struct nlm_host *);
struct nlm_host  *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
                                        const char *hostname,
                                        const size_t hostname_len);
void              nlmsvc_release_host(struct nlm_host *);
struct rpc_clnt * nlm_bind_host(struct nlm_host *);
void              nlm_rebind_host(struct nlm_host *);
struct nlm_host * nlm_get_host(struct nlm_host *);
void              nlm_shutdown_hosts(void);
void              nlm_shutdown_hosts_net(struct net *net);
void              nlm_host_rebooted(const struct net *net,
                                        const struct nlm_reboot *);

/*
 * Host monitoring
 */
int               nsm_monitor(const struct nlm_host *host);
void              nsm_unmonitor(const struct nlm_host *host);

struct nsm_handle *nsm_get_handle(const struct net *net,
                                        const struct sockaddr *sap,
                                        const size_t salen,
                                        const char *hostname,
                                        const size_t hostname_len);
struct nsm_handle *nsm_reboot_lookup(const struct net *net,
                                        const struct nlm_reboot *info);
void              nsm_release(struct nsm_handle *nsm);

/*
 * This is used in garbage collection and resource reclaim
 * A return value != 0 means destroy the lock/block/share
 */
typedef int       (*nlm_host_match_fn_t)(void *cur, struct nlm_host *ref);

/*
 * Server-side lock handling
 */
int               lock_to_openmode(struct file_lock *);
__be32            nlmsvc_lock(struct svc_rqst *, struct nlm_file *,
                              struct nlm_host *, struct nlm_lock *, int,
                              struct nlm_cookie *, int);
__be32            nlmsvc_unlock(struct net *net, struct nlm_file *, struct nlm_lock *);
__be32            nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
                        struct nlm_host *host, struct nlm_lock *lock,
                        struct nlm_lock *conflock);
__be32            nlmsvc_cancel_blocked(struct net *net, struct nlm_file *, struct nlm_lock *);
void              nlmsvc_retry_blocked(struct svc_rqst *rqstp);
void              nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *,
                                        nlm_host_match_fn_t match);
void              nlmsvc_grant_reply(struct nlm_cookie *, __be32);
void              nlmsvc_release_call(struct nlm_rqst *);
void              nlmsvc_locks_init_private(struct file_lock *, struct nlm_host *, pid_t);

/*
 * File handling for the server personality
 */
__be32            nlm_lookup_file(struct svc_rqst *, struct nlm_file **,
                                        struct nlm_lock *);
void              nlm_release_file(struct nlm_file *);
void              nlmsvc_put_lockowner(struct nlm_lockowner *);
void              nlmsvc_release_lockowner(struct nlm_lock *);
void              nlmsvc_mark_resources(struct net *);
void              nlmsvc_free_host_resources(struct nlm_host *);
void              nlmsvc_invalidate_all(void);

/*
 * Cluster failover support
 */
int           nlmsvc_unlock_all_by_sb(struct super_block *sb);
int           nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);

static inline struct file *nlmsvc_file_file(const struct nlm_file *file)
{
        return file->f_file[O_RDONLY] ?
               file->f_file[O_RDONLY] : file->f_file[O_WRONLY];
}

static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
{
        return file_inode(nlmsvc_file_file(file));
}

static inline bool
nlmsvc_file_cannot_lock(const struct nlm_file *file)
{
        return exportfs_cannot_lock(nlmsvc_file_file(file)->f_path.dentry->d_sb->s_export_op);
}

static inline int __nlm_privileged_request4(const struct sockaddr *sap)
{
        const struct sockaddr_in *sin = (struct sockaddr_in *)sap;

        if (ntohs(sin->sin_port) > 1023)
                return 0;

        return ipv4_is_loopback(sin->sin_addr.s_addr);
}

#if IS_ENABLED(CONFIG_IPV6)
static inline int __nlm_privileged_request6(const struct sockaddr *sap)
{
        const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;

        if (ntohs(sin6->sin6_port) > 1023)
                return 0;

        if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_MAPPED)
                return ipv4_is_loopback(sin6->sin6_addr.s6_addr32[3]);

        return ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LOOPBACK;
}
#else   /* IS_ENABLED(CONFIG_IPV6) */
static inline int __nlm_privileged_request6(const struct sockaddr *sap)
{
        return 0;
}
#endif  /* IS_ENABLED(CONFIG_IPV6) */

/*
 * Ensure incoming requests are from local privileged callers.
 *
 * Return TRUE if sender is local and is connecting via a privileged port;
 * otherwise return FALSE.
 */
static inline int nlm_privileged_requester(const struct svc_rqst *rqstp)
{
        const struct sockaddr *sap = svc_addr(rqstp);

        switch (sap->sa_family) {
        case AF_INET:
                return __nlm_privileged_request4(sap);
        case AF_INET6:
                return __nlm_privileged_request6(sap);
        default:
                return 0;
        }
}

/*
 * Compare two NLM locks.
 * When the second lock is of type F_UNLCK, this acts like a wildcard.
 */
static inline int nlm_compare_locks(const struct file_lock *fl1,
                                    const struct file_lock *fl2)
{
        return file_inode(fl1->c.flc_file) == file_inode(fl2->c.flc_file)
             && fl1->c.flc_pid   == fl2->c.flc_pid
             && fl1->c.flc_owner == fl2->c.flc_owner
             && fl1->fl_start == fl2->fl_start
             && fl1->fl_end   == fl2->fl_end
             &&(fl1->c.flc_type  == fl2->c.flc_type || fl2->c.flc_type == F_UNLCK);
}

extern const struct lock_manager_operations nlmsvc_lock_operations;

#endif /* LINUX_LOCKD_LOCKD_H */