/* 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 */
