Manpages - rpc.3t

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.

All RPC routines require the header

Routines that take a

also require that

be included.

Some of the high-level RPC interface routines take a

string as one of the arguments (for example,

This string defines a class of transports which can be used for a particular application.

The

argument can be one of the following:

Choose from the transports which have been indicated by their token names in the

environment variable.

is unset or

it defaults to

is the default

Choose the transports which have the visible flag (v) set in the

file.

This is same as

except that it chooses only the connection oriented transports (semantics

or

from the entries in the

file.

This is same as

except that it chooses only the connectionless datagram transports (semantics

from the entries in the

file.

This is same as

except that it chooses only the connection oriented datagram transports (semantics

or

This is same as

except that it chooses only the connectionless datagram transports (semantics

This refers to Internet UDP, both version 4 and 6.

This refers to Internet TCP, both version 4 and 6.

If

is

it defaults to

The transports are tried in left to right order in the

variable or in top to down order in the

file.

The derived types used in the RPC interfaces are defined as follows:

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;

Some of the data structures used by the RPC package are shown below.

* * Authentication info. Opaque to client. * struct opaque_auth { enum_t oa_flavor; * flavor of auth * caddr_t oa_base; * address of more auth stuff * u_int oa_length; * not to exceed MAX_AUTH_BYTES * };

* * Auth handle, interface to client side authenticators. * typedef struct { struct opaque_auth ah_cred; struct opaque_auth ah_verf; 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; caddr_t ah_private; } AUTH;

* * Client rpc handle. * Created by individual implementations. * Client is responsible for initializing auth. *

typedef struct { AUTH cl_auth; / authenticator / struct clnt_ops { enum clnt_stat (*cl_call)(); / call remote procedure / void (*cl_abort)(); / abort a call / void (*cl_geterr)(); / get specific error code / bool_t (*cl_freeres)(); / frees results / void (*cl_destroy)(); / destroy this structure / bool_t (*cl_control)(); / the ioctl() of rpc / } *cl_ops; caddr_t cl_private; / private stuff / char *cl_netid; / network identifier / char *cl_tp; / device name */ } CLIENT;

enum xprt_stat { XPRT_DIED, XPRT_MOREREQS, XPRT_IDLE };

* * Server side transport handle * typedef struct { int xp_fd; * file descriptor for the server handle * u_short xp_port; * obsolete * const struct xp_ops { bool_t (xp_recv)(); / receive incoming requests / enum xprt_stat (*xp_stat)(); / get transport status / bool_t (*xp_getargs)(); / get arguments / bool_t (*xp_reply)(); / send reply / bool_t (*xp_freeargs)(); / free mem allocated for args / void (*xp_destroy)(); / destroy this struct / } *xp_ops; int xp_addrlen; / length of remote addr. Obsolete / struct sockaddr_in xp_raddr; / Obsolete / const struct xp_ops2 { bool_t (*xp_control)(); / catch-all function / } *xp_ops2; char *xp_tp; / transport provider device name / char *xp_netid; / network identifier / struct netbuf xp_ltaddr; / local transport address / struct netbuf xp_rtaddr; / remote transport address / struct opaque_auth xp_verf; / raw response verifier / caddr_t xp_p1; / private: for use by svc ops / caddr_t xp_p2; / private: for use by svc ops / caddr_t xp_p3; / private: for use by svc lib / int xp_type / transport type */ } SVCXPRT;

struct svc_req { rpcprog_t rq_prog; * service program number * rpcvers_t rq_vers; * service protocol version * rpcproc_t rq_proc; * the desired procedure * struct opaque_auth rq_cred; * raw creds from the wire * caddr_t rq_clntcred; * read only cooked cred * SVCXPRT rq_xprt; / associated transport */ };

* * 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) \ * 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 *, caddr_t *); * 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 * 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; caddr_t x_public; / users’ data / caddr_t x_private; / pointer to private data / caddr_t x_base; / private used for position info / u_int x_handy; / extra private word */ } XDR;

/* * The netbuf structure. This structure is defined in <xti.h> on SysV