.\" @(#)rpc.3n 1.31 93/08/31 SMI; from SVr4
.\" Copyright 1989 AT&T
.Dd May 7, 1993
.Dt RPC 3
.Os
.Sh NAME
.Nm rpc
.Nd library routines for remote procedure calls
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In rpc/rpc.h
.In netconfig.h
.Sh DESCRIPTION
These
routines allow C language programs to make procedure
calls on other machines across a network.
First, the client sends a request to the server.
On receipt of the request, the server calls a dispatch routine
to perform the requested service, and then sends back a reply.
.Pp
All
RPC routines require the header
.In rpc/rpc.h .
Routines that take a
.Vt "struct netconfig"
also require that
.In netconfig.h
be included.
.Sh Nettype
Some of the high-level
RPC interface routines take a
.Fa nettype
string as one of the arguments
(for example,
.Fn clnt_create ,
.Fn svc_create ,
.Fn rpc_reg ,
.Fn rpc_call ) .
This string defines a class of transports which can be used
for a particular application.
.Pp
The
.Fa nettype
argument
can be one of the following:
.Bl -tag -width datagram_v
.It netpath
Choose from the transports which have been
indicated by their token names in the
.Ev NETPATH
environment variable.
.Ev NETPATH
is unset or
.Dv NULL ,
it defaults to
.Qq visible .
.Qq netpath
is the default
.Fa nettype .
.It visible
Choose the transports which have the visible flag (v)
set in the
.Pa /etc/netconfig
file.
.It circuit_v
This is same as
.Qq visible
except that it chooses only the connection oriented transports
(semantics
.Qq tpi_cots
or
.Qq tpi_cots_ord )
from the entries in the
.Pa /etc/netconfig
file.
.It datagram_v
This is same as
.Qq visible
except that it chooses only the connectionless datagram transports
(semantics
.Qq tpi_clts )
from the entries in the
.Pa /etc/netconfig
file.
.It circuit_n
This is same as
.Qq netpath
except that it chooses only the connection oriented datagram transports
(semantics
.Qq tpi_cots
or
.Qq tpi_cots_ord ) .
.It datagram_n
This is same as
.Qq netpath
except that it chooses only the connectionless datagram transports
(semantics
.Qq tpi_clts ) .
.It udp
This refers to Internet UDP, both version 4 and 6.
.It tcp
This refers to Internet TCP, both version 4 and 6.
.El
.Pp
If
.Fa nettype
is
.Dv NULL ,
it defaults to
.Qq netpath .
The transports are tried in left to right order in the
.Ev NETPATH
variable or in top to down order in the
.Pa /etc/netconfig
file.
.Sh Derived Types
The derived types used in the RPC interfaces are defined as follows:
.Bd -literal
	typedef u_int32_t rpcprog_t;
	typedef u_int32_t rpcvers_t;
	typedef u_int32_t rpcproc_t;
	typedef u_int32_t rpcprot_t;
	typedef u_int32_t rpcport_t;
	typedef   int32_t rpc_inline_t;
.Ed
.Sh "Data Structures"
Some of the data structures used by the
RPC package are shown below.
.Sh "The AUTH Structure"
.Bd -literal
/*
 * Authentication info. Opaque to client.
 */
struct opaque_auth {
    enum_t    oa_flavor;    /* flavor of auth */
    u_int    oa_length;    /* not to exceed MAX_AUTH_BYTES */
    char    oa_body[MAX_AUTH_BYTES];
};

/*
 * Auth handle, interface to client side authenticators.
 */
typedef struct {
    struct auth_ops {
        void    (*ah_nextverf)(\|);
        int    (*ah_marshal)(\|);    /* nextverf & serialize */
        int    (*ah_validate)(\|);    /* validate verifier */
        int    (*ah_refresh)(\|);    /* refresh credentials */
        void    (*ah_destroy)(\|);    /* destroy this structure */
    } *ah_ops;
    struct opaque_auth  ah_cred;
    struct opaque_auth  ah_verf;
    void *ah_private;
} AUTH;
.Ed
.Sh "The CLIENT Structure"
.Bd -literal
/*
 * Client rpc handle.
 * Created by individual implementations.
 * Client is responsible for initializing auth.
 */

typedef struct {
    struct clnt_ops {
        enum clnt_stat    (*cl_call)();    /* call remote procedure */
        void    (*cl_abort)();        /* abort a call */
        bool_t    (*cl_freeres)();    /* frees results */
        void    (*cl_destroy)();    /* destroy this structure */
        bool_t    (*cl_control)();    /* the ioctl() of rpc */
    } *cl_ops;

    char    *cl_netid;    /* network identifier */
    char    *cl_tp;        /* device name */
    void *cl_u1;           /* client user data */
    void *cl_u2;           /* client user data */
    struct rpc_err cl_error; /* specific error code */
} CLIENT;
.Ed
.Sh "The SVCXPRT structure"
.Bd -literal
enum xprt_stat {
    XPRT_IDLE = 0,
    XPRT_DIED,
    XPRT_DESTROYED
};

/*
 * Server side transport handle
 */
typedef struct {
    const struct xp_ops {
        enum xprt_stat    (*xp_recv)();    /* receive incoming requests */
        enum xprt_stat    (*xp_stat)();    /* get transport status */
        enum xprt_stat    (*xp_decode)();  /* get arguments */
        enum xprt_stat    (*xp_reply)();   /* send reply */
        void    (*xp_checksum)();          /* checksum for cache */
        void    (*xp_destroy)();    /* destroy this struct */
        bool_t    (*xp_control)();    /* catch-all function */
    } *xp_ops;
    char    *xp_tp;    /* transport provider device name */
    char    *xp_netid;    /* network identifier */
    void *xp_p1;    /* private: for use by svc ops */
    void *xp_p2;    /* private: for use by svc ops */
    void *xp_p3;    /* private: for use by svc lib */
    void *xp_u1;    /* public: user data */
    void *xp_u2;    /* public: user data */
    struct rpc_address xp_local;	/* local address, length, port */
    struct rpc_address xp_remote;	/* remote address, length, port */
    int    xp_fd;    /* file descriptor for the server handle */
    int    xp_type    /* transport type */
} SVCXPRT;
.Ed
.Sh "The svc_req structure"
.Bd -literal
struct svc_req {
    SVCXPRT    *rq_xprt;    /* associated transport */
    struct rpc_msg rq_msg;
};
.Ed
.Sh  "The XDR structure"
.Bd -literal
/*
 * XDR operations.
 * XDR_ENCODE causes the type to be encoded into the stream.
 * XDR_DECODE causes the type to be extracted from the stream.
 * XDR_FREE can be used to release the space allocated by an XDR_DECODE
 * request.
 */
enum xdr_op {
    XDR_ENCODE=0,
    XDR_DECODE=1,
    XDR_FREE=2
};
/*
 * This is the number of bytes per unit of external data.
 */
#define BYTES_PER_XDR_UNIT    (4)
#define RNDUP(x)  ((((x) + BYTES_PER_XDR_UNIT - 1) /
                   BYTES_PER_XDR_UNIT) \e * BYTES_PER_XDR_UNIT)

/*
 * A xdrproc_t exists for each data type which is to be encoded or
 * decoded.  The second argument to the xdrproc_t is a pointer to
 * an opaque pointer.  The opaque pointer generally points to a
 * structure of the data type to be decoded.  If this points to 0,
 * then the type routines should allocate dynamic storage of the
 * appropriate size and return it.
 * bool_t  (*xdrproc_t)(XDR *, ...);
 */
typedef  bool_t (*xdrproc_t)();

/*
 * The XDR handle.
 * Contains operation which is being applied to the stream,
 * an operations vector for the particular implementation
 */
typedef struct {
    enum xdr_op    x_op;    /* operation; fast additional param */
    const struct xdr_ops {
        bool_t    (*x_getlong)();    /* get a long from underlying stream */
        bool_t    (*x_putlong)();    /* put a long to underlying stream */
        bool_t    (*x_getbytes)(); /* get bytes from underlying stream */
        bool_t    (*x_putbytes)(); /* put bytes to underlying stream */
        u_int    (*x_getpostn)(); /* returns bytes off from beginning */
        bool_t    (*x_setpostn)(); /* lets you reposition the stream */
        long *    (*x_inline)();    /* buf quick ptr to buffered data */
        void    (*x_destroy)();    /* free privates of this xdr_stream */
    } *x_ops;
    void *x_public; /* users' data */
    void *x_private; /* pointer to private data */
    void *x_lib[2]; /* RPC library private */
    uint8_t *x_data;  /* private used for position inline */
    void *x_base;  /* private used for position info */
    struct xdr_vio x_v; /* private buffer vector */
    u_int x_handy; /* extra private word */
    u_int x_flags; /* shared flags */
} XDR;

/*
 * The netbuf structure. This structure is defined in <xti.h> on SysV
 * systems, but NetBSD / FreeBSD do not use XTI.
 *
 * Usually, buf will point to a struct sockaddr, and len and maxlen
 * will contain the length and maximum length of that socket address,
 * respectively.
 */
struct netbuf {
	unsigned int maxlen;
	unsigned int len;
	void *buf;
};

/*
 * The format of the address and options arguments of the XTI t_bind call.
 * Only provided for compatibility, it should not be used other than
 * as an argument to svc_tli_create().
 */

struct t_bind {
	struct netbuf   addr;
	unsigned int    qlen;
};
.Ed
.Sh "Index to Routines"
The following table lists RPC routines and the manual reference
pages on which they are described:
.Pp
.Bl -tag -width "authunix_create_default()" -compact
.It Em "RPC Routine"
.Em "Manual Reference Page"
.Pp
.It Fn auth_destroy
.Xr rpc_clnt_auth 3
.It Fn authnone_create
.Xr rpc_clnt_auth 3
.It Fn authsys_create
.Xr rpc_clnt_auth 3
.It Fn authsys_create_default
.Xr rpc_clnt_auth 3
.It Fn authunix_create
.Xr rpc_soc 3
.It Fn authunix_create_default
.Xr rpc_soc 3
.It Fn clnt_call
.Xr rpc_clnt_calls 3
.It Fn clnt_control
.Xr rpc_clnt_create 3
.It Fn clnt_create
.Xr rpc_clnt_create 3
.It Fn clnt_create_timed
.Xr rpc_clnt_create 3
.It Fn clnt_create_vers
.Xr rpc_clnt_create 3
.It Fn clnt_create_vers_timed
.Xr rpc_clnt_create 3
.It Fn clnt_destroy
.Xr rpc_clnt_create 3
.It Fn clnt_dg_create
.Xr rpc_clnt_create 3
.It Fn clnt_freeres
.Xr rpc_clnt_calls 3
.It Fn clnt_perrno
.Xr rpc_clnt_calls 3
.It Fn clnt_raw_create
.Xr rpc_clnt_create 3
.It Fn clnt_sperrno
.Xr rpc_clnt_calls 3
.It Fn clnt_tli_create
.Xr rpc_clnt_create 3
.It Fn clnt_tp_create
.Xr rpc_clnt_create 3
.It Fn clnt_tp_create_timed
.Xr rpc_clnt_create 3
.It Fn clnt_udpcreate
.Xr rpc_soc 3
.It Fn clnt_vc_create
.Xr rpc_clnt_create 3
.It Fn rpc_broadcast
.Xr rpc_clnt_calls 3
.It Fn rpc_broadcast_exp
.Xr rpc_clnt_calls 3
.It Fn rpc_call
.Xr rpc_clnt_calls 3
.It Fn rpc_perror
.Xr rpc_soc 3
.It Fn rpc_sperror
.Xr rpc_soc 3
.It Fn rpc_reg
.Xr rpc_svc_calls 3
.It Fn svc_create
.Xr rpc_svc_create 3
.It Fn svc_destroy
.Xr rpc_svc_create 3
.It Fn svc_dg_create
.Xr rpc_svc_create 3
.It Fn svc_fd_create
.Xr rpc_svc_create 3
.It Fn svc_getrpccaller
.Xr rpc_svc_calls 3
.It Fn svc_kerb_reg
.Xr kerberos_rpc 3
.It Fn svc_raw_create
.Xr rpc_svc_create 3
.It Fn svc_reg
.Xr rpc_svc_calls 3
.It Fn svc_sendreply
.Xr rpc_svc_reg 3
.It Fn svc_tli_create
.Xr rpc_svc_create 3
.It Fn svc_tp_create
.Xr rpc_svc_create 3
.It Fn svc_unreg
.Xr rpc_svc_calls 3
.It Fn svc_vc_create
.Xr rpc_svc_create 3
.It Fn svcerr_auth
.Xr rpc_svc_err 3
.It Fn svcerr_decode
.Xr rpc_svc_err 3
.It Fn svcerr_noproc
.Xr rpc_svc_err 3
.It Fn svcerr_noprog
.Xr rpc_svc_err 3
.It Fn svcerr_progvers
.Xr rpc_svc_err 3
.It Fn svcerr_systemerr
.Xr rpc_svc_err 3
.It Fn svcerr_weakauth
.Xr rpc_svc_err 3
.It Fn xdr_accepted_reply
.Xr rpc_xdr 3
.It Fn xdr_authsys_parms
.Xr rpc_xdr 3
.It Fn xdr_authunix_parms
.Xr rpc_soc 3
.It Fn xdr_callhdr
.Xr rpc_xdr 3
.It Fn xdr_callmsg
.Xr rpc_xdr 3
.It Fn xdr_opaque_auth
.Xr rpc_xdr 3
.It Fn xdr_rejected_reply
.Xr rpc_xdr 3
.It Fn xdr_replymsg
.Xr rpc_xdr 3
.El
.Sh FILES
.Bl -tag -width /etc/netconfig
.It Pa /etc/netconfig
.El
.Sh SEE ALSO
.Xr getnetconfig 3 ,
.Xr getnetpath 3 ,
.Xr rpcbind 3 ,
.Xr rpc_clnt_auth 3 ,
.Xr rpc_clnt_calls 3 ,
.Xr rpc_clnt_create 3 ,
.Xr rpc_svc_calls 3 ,
.Xr rpc_svc_create 3 ,
.Xr rpc_svc_err 3 ,
.Xr rpc_svc_reg 3 ,
.Xr rpc_xdr 3 ,
.Xr xdr 3 ,
.Xr netconfig 5