/* SPDX-License-Identifier: GPL-2.0 */
/*
 * linux/include/linux/sunrpc/svc_xprt.h
 *
 * RPC server transport I/O
 */

#ifndef SUNRPC_SVC_XPRT_H
#define SUNRPC_SVC_XPRT_H

#include <linux/sunrpc/svc.h>

struct module;

struct svc_xprt_ops {
        struct svc_xprt *(*xpo_create)(struct svc_serv *,
                                       struct net *net,
                                       struct sockaddr *, int,
                                       int);
        struct svc_xprt *(*xpo_accept)(struct svc_xprt *);
        int             (*xpo_has_wspace)(struct svc_xprt *);
        int             (*xpo_recvfrom)(struct svc_rqst *);
        int             (*xpo_sendto)(struct svc_rqst *);
        int             (*xpo_result_payload)(struct svc_rqst *, unsigned int,
                                              unsigned int);
        void            (*xpo_release_ctxt)(struct svc_xprt *xprt, void *ctxt);
        void            (*xpo_detach)(struct svc_xprt *);
        void            (*xpo_free)(struct svc_xprt *);
        void            (*xpo_kill_temp_xprt)(struct svc_xprt *);
        void            (*xpo_handshake)(struct svc_xprt *xprt);
};

struct svc_xprt_class {
        const char              *xcl_name;
        struct module           *xcl_owner;
        const struct svc_xprt_ops *xcl_ops;
        struct list_head        xcl_list;
        u32                     xcl_max_payload;
        int                     xcl_ident;
};

/*
 * This is embedded in an object that wants a callback before deleting
 * an xprt; intended for use by NFSv4.1, which needs to know when a
 * client's tcp connection (and hence possibly a backchannel) goes away.
 */
struct svc_xpt_user {
        struct list_head list;
        void (*callback)(struct svc_xpt_user *);
};

struct svc_xprt {
        struct svc_xprt_class   *xpt_class;
        const struct svc_xprt_ops *xpt_ops;
        struct kref             xpt_ref;
        ktime_t                 xpt_qtime;
        struct list_head        xpt_list;
        struct lwq_node         xpt_ready;
        unsigned long           xpt_flags;

        struct svc_serv         *xpt_server;    /* service for transport */
        atomic_t                xpt_reserved;   /* space on outq that is rsvd */
        atomic_t                xpt_nr_rqsts;   /* Number of requests */
        struct mutex            xpt_mutex;      /* to serialize sending data */
        spinlock_t              xpt_lock;       /* protects sk_deferred
                                                 * and xpt_auth_cache */
        void                    *xpt_auth_cache;/* auth cache */
        struct list_head        xpt_deferred;   /* deferred requests that need
                                                 * to be revisted */
        struct sockaddr_storage xpt_local;      /* local address */
        size_t                  xpt_locallen;   /* length of address */
        struct sockaddr_storage xpt_remote;     /* remote peer's address */
        size_t                  xpt_remotelen;  /* length of address */
        char                    xpt_remotebuf[INET6_ADDRSTRLEN + 10];
        struct list_head        xpt_users;      /* callbacks on free */

        struct net              *xpt_net;
        netns_tracker           ns_tracker;
        const struct cred       *xpt_cred;
        struct rpc_xprt         *xpt_bc_xprt;   /* NFSv4.1 backchannel */
        struct rpc_xprt_switch  *xpt_bc_xps;    /* NFSv4.1 backchannel */
};

/* flag bits for xpt_flags */
enum {
        XPT_BUSY,               /* enqueued/receiving */
        XPT_CONN,               /* conn pending */
        XPT_CLOSE,              /* dead or dying */
        XPT_DATA,               /* data pending */
        XPT_TEMP,               /* connected transport */
        XPT_DEAD,               /* transport closed */
        XPT_CHNGBUF,            /* need to change snd/rcv buf sizes */
        XPT_DEFERRED,           /* deferred request pending */
        XPT_OLD,                /* used for xprt aging mark+sweep */
        XPT_LISTENER,           /* listening endpoint */
        XPT_CACHE_AUTH,         /* cache auth info */
        XPT_LOCAL,              /* connection from loopback interface */
        XPT_KILL_TEMP,          /* call xpo_kill_temp_xprt before closing */
        XPT_CONG_CTRL,          /* has congestion control */
        XPT_HANDSHAKE,          /* xprt requests a handshake */
        XPT_TLS_SESSION,        /* transport-layer security established */
        XPT_PEER_AUTH,          /* peer has been authenticated */
        XPT_PEER_VALID,         /* peer has presented a filehandle that
                                 * it has access to.  It is NOT counted
                                 * in ->sv_tmpcnt.
                                 */
        XPT_RPCB_UNREG,         /* transport that needs unregistering
                                 * with rpcbind (TCP, UDP) on destroy
                                 */
};

/*
 * Maximum number of "tmp" connections - those without XPT_PEER_VALID -
 * permitted on any service.
 */
#define XPT_MAX_TMP_CONN        64

static inline void svc_xprt_set_valid(struct svc_xprt *xpt)
{
        if (test_bit(XPT_TEMP, &xpt->xpt_flags) &&
            !test_and_set_bit(XPT_PEER_VALID, &xpt->xpt_flags)) {
                struct svc_serv *serv = xpt->xpt_server;

                spin_lock(&serv->sv_lock);
                serv->sv_tmpcnt -= 1;
                spin_unlock(&serv->sv_lock);
        }
}

static inline void unregister_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
{
        spin_lock(&xpt->xpt_lock);
        list_del_init(&u->list);
        spin_unlock(&xpt->xpt_lock);
}

static inline int register_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
{
        spin_lock(&xpt->xpt_lock);
        if (test_bit(XPT_CLOSE, &xpt->xpt_flags)) {
                /*
                 * The connection is about to be deleted soon (or,
                 * worse, may already be deleted--in which case we've
                 * already notified the xpt_users).
                 */
                spin_unlock(&xpt->xpt_lock);
                return -ENOTCONN;
        }
        list_add(&u->list, &xpt->xpt_users);
        spin_unlock(&xpt->xpt_lock);
        return 0;
}

static inline bool svc_xprt_is_dead(const struct svc_xprt *xprt)
{
        return (test_bit(XPT_DEAD, &xprt->xpt_flags) != 0) ||
                (test_bit(XPT_CLOSE, &xprt->xpt_flags) != 0);
}

int     svc_reg_xprt_class(struct svc_xprt_class *);
void    svc_unreg_xprt_class(struct svc_xprt_class *);
void    svc_xprt_init(struct net *, struct svc_xprt_class *, struct svc_xprt *,
                      struct svc_serv *);
int     svc_xprt_create_from_sa(struct svc_serv *serv, const char *xprt_name,
                                struct net *net, struct sockaddr *sap,
                                int flags, const struct cred *cred);
int     svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
                        struct net *net, const int family,
                        const unsigned short port, int flags,
                        const struct cred *cred);
void    svc_xprt_destroy_all(struct svc_serv *serv, struct net *net,
                             bool unregister);
void    svc_xprt_received(struct svc_xprt *xprt);
void    svc_xprt_enqueue(struct svc_xprt *xprt);
void    svc_xprt_put(struct svc_xprt *xprt);
void    svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt);
void    svc_xprt_close(struct svc_xprt *xprt);
int     svc_port_is_privileged(struct sockaddr *sin);
int     svc_print_xprts(char *buf, int maxlen);
struct svc_xprt *svc_find_listener(struct svc_serv *serv, const char *xcl_name,
                                   struct net *net, const struct sockaddr *sa);
struct  svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
                        struct net *net, const sa_family_t af,
                        const unsigned short port);
int     svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen);
void    svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *xprt);
void    svc_age_temp_xprts_now(struct svc_serv *, struct sockaddr *);
void    svc_xprt_deferred_close(struct svc_xprt *xprt);

static inline void svc_xprt_get(struct svc_xprt *xprt)
{
        kref_get(&xprt->xpt_ref);
}
static inline void svc_xprt_set_local(struct svc_xprt *xprt,
                                      const struct sockaddr *sa,
                                      const size_t salen)
{
        memcpy(&xprt->xpt_local, sa, salen);
        xprt->xpt_locallen = salen;
}
static inline void svc_xprt_set_remote(struct svc_xprt *xprt,
                                       const struct sockaddr *sa,
                                       const size_t salen)
{
        memcpy(&xprt->xpt_remote, sa, salen);
        xprt->xpt_remotelen = salen;
        snprintf(xprt->xpt_remotebuf, sizeof(xprt->xpt_remotebuf) - 1,
                 "%pISpc", sa);
}

static inline unsigned short svc_addr_port(const struct sockaddr *sa)
{
        const struct sockaddr_in *sin = (const struct sockaddr_in *)sa;
        const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sa;

        switch (sa->sa_family) {
        case AF_INET:
                return ntohs(sin->sin_port);
        case AF_INET6:
                return ntohs(sin6->sin6_port);
        }

        return 0;
}

static inline size_t svc_addr_len(const struct sockaddr *sa)
{
        switch (sa->sa_family) {
        case AF_INET:
                return sizeof(struct sockaddr_in);
        case AF_INET6:
                return sizeof(struct sockaddr_in6);
        }
        BUG();
}

static inline unsigned short svc_xprt_local_port(const struct svc_xprt *xprt)
{
        return svc_addr_port((const struct sockaddr *)&xprt->xpt_local);
}

static inline unsigned short svc_xprt_remote_port(const struct svc_xprt *xprt)
{
        return svc_addr_port((const struct sockaddr *)&xprt->xpt_remote);
}

static inline char *__svc_print_addr(const struct sockaddr *addr,
                                     char *buf, const size_t len)
{
        const struct sockaddr_in *sin = (const struct sockaddr_in *)addr;
        const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)addr;

        switch (addr->sa_family) {
        case AF_INET:
                snprintf(buf, len, "%pI4, port=%u", &sin->sin_addr,
                        ntohs(sin->sin_port));
                break;

        case AF_INET6:
                snprintf(buf, len, "%pI6, port=%u",
                         &sin6->sin6_addr,
                        ntohs(sin6->sin6_port));
                break;

        default:
                snprintf(buf, len, "unknown address type: %d", addr->sa_family);
                break;
        }

        return buf;
}
#endif /* SUNRPC_SVC_XPRT_H */