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rpc - library routines for remote procedure calls


Derived Types
See Also


.Lb libc


.In rpc/rpc.h
.In netconfig.h


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
.In rpc/rpc.h . Routines that take a
.Vt "struct netconfig" also require that
.In netconfig.h be included.


Some of the high-level RPC interface routines take a nettype string as one of the arguments (for example, clnt_create, svc_create, rpc_reg, rpc_call). This string defines a class of transports which can be used for a particular application.

The nettype argument can be one of the following:

netpath Choose from the transports which have been indicated by their token names in the NETPATH environment variable. NETPATH is unset or NULL, it defaults to "visible". "netpath" is the default nettype.
visible Choose the transports which have the visible flag (v) set in the /etc/netconfig file.
circuit_v This is same as "visible" except that it chooses only the connection oriented transports (semantics "tpi_cots" or "tpi_cots_ord") from the entries in the /etc/netconfig file.
This is same as "visible" except that it chooses only the connectionless datagram transports (semantics "tpi_clts") from the entries in the /etc/netconfig file.
circuit_n This is same as "netpath" except that it chooses only the connection oriented datagram transports (semantics "tpi_cots" or "tpi_cots_ord").
This is same as "netpath" except that it chooses only the connectionless datagram transports (semantics "tpi_clts").
udp This refers to Internet UDP, both version 4 and 6.
tcp This refers to Internet TCP, both version 4 and 6.

If nettype is NULL, it defaults to "netpath". The transports are tried in left to right order in the NETPATH variable or in top to down order in the /etc/netconfig file.

Derived Types

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;

"Data Structures"

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

"The AUTH Structure"

* 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;

"The CLIENT Structure"

* 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 */

"The SVCXPRT structure"

enum xprt_stat {

* 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 */

"The svc_reg structure"

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 */

"The XDR structure"

* 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 {
* 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) /

* 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
* 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;

"Index to Routines"

The following table lists RPC routines and the manual reference pages on which they are described:

"RPC Routine" "Manual Reference Page"

auth_destroy rpc_clnt_auth(3)
authdes_create rpc_soc(3)
authnone_create rpc_clnt_auth(3)
authsys_create rpc_clnt_auth(3)
authsys_create_default rpc_clnt_auth(3)
authunix_create rpc_soc(3)
authunix_create_default rpc_soc(3)
callrpc rpc_soc(3)
clnt_broadcast rpc_soc(3)
clnt_call rpc_clnt_calls(3)
clnt_control rpc_clnt_create(3)
clnt_create rpc_clnt_create(3)
clnt_create_timed rpc_clnt_create(3)
clnt_create_vers rpc_clnt_create(3)
clnt_create_vers_timed rpc_clnt_create(3)
clnt_destroy rpc_clnt_create(3)
clnt_dg_create rpc_clnt_create(3)
clnt_freeres rpc_clnt_calls(3)
clnt_geterr rpc_clnt_calls(3)
clnt_pcreateerror rpc_clnt_create(3)
clnt_perrno rpc_clnt_calls(3)
clnt_perror rpc_clnt_calls(3)
clnt_raw_create rpc_clnt_create(3)
clnt_spcreateerror rpc_clnt_create(3)
clnt_sperrno rpc_clnt_calls(3)
clnt_sperror rpc_clnt_calls(3)
clnt_tli_create rpc_clnt_create(3)
clnt_tp_create rpc_clnt_create(3)
clnt_tp_create_timed rpc_clnt_create(3)
clnt_udpcreate rpc_soc(3)
clnt_vc_create rpc_clnt_create(3)
clntraw_create rpc_soc(3)
clnttcp_create rpc_soc(3)
clntudp_bufcreate rpc_soc(3)
get_myaddress rpc_soc(3)
pmap_getmaps rpc_soc(3)
pmap_getport rpc_soc(3)
pmap_rmtcall rpc_soc(3)
pmap_set rpc_soc(3)
pmap_unset rpc_soc(3)
registerrpc rpc_soc(3)
rpc_broadcast rpc_clnt_calls(3)
rpc_broadcast_exp rpc_clnt_calls(3)
rpc_call rpc_clnt_calls(3)
rpc_reg rpc_svc_calls(3)
svc_create rpc_svc_create(3)
svc_destroy rpc_svc_create(3)
svc_dg_create rpc_svc_create(3)
svc_dg_enablecache rpc_svc_calls(3)
svc_fd_create rpc_svc_create(3)
svc_fds rpc_soc(3)
svc_freeargs rpc_svc_reg(3)
svc_getargs rpc_svc_reg(3)
svc_getcaller rpc_soc(3)
svc_getreq rpc_soc(3)
svc_getreqset rpc_svc_calls(3)
svc_getrpccaller rpc_svc_calls(3)
svc_kerb_reg kerberos_rpc(3)
svc_raw_create rpc_svc_create(3)
svc_reg rpc_svc_calls(3)
svc_register rpc_soc(3)
svc_run rpc_svc_reg(3)
svc_sendreply rpc_svc_reg(3)
svc_tli_create rpc_svc_create(3)
svc_tp_create rpc_svc_create(3)
svc_unreg rpc_svc_calls(3)
svc_unregister rpc_soc(3)
svc_vc_create rpc_svc_create(3)
svcerr_auth rpc_svc_err(3)
svcerr_decode rpc_svc_err(3)
svcerr_noproc rpc_svc_err(3)
svcerr_noprog rpc_svc_err(3)
svcerr_progvers rpc_svc_err(3)
svcerr_systemerr rpc_svc_err(3)
svcerr_weakauth rpc_svc_err(3)
svcfd_create rpc_soc(3)
svcraw_create rpc_soc(3)
svctcp_create rpc_soc(3)
svcudp_bufcreate rpc_soc(3)
svcudp_create rpc_soc(3)
xdr_accepted_reply rpc_xdr(3)
xdr_authsys_parms rpc_xdr(3)
xdr_authunix_parms rpc_soc(3)
xdr_callhdr rpc_xdr(3)
xdr_callmsg rpc_xdr(3)
xdr_opaque_auth rpc_xdr(3)
xdr_rejected_reply rpc_xdr(3)
xdr_replymsg rpc_xdr(3)
xprt_register rpc_svc_calls(3)
xprt_unregister rpc_svc_calls(3)




getnetconfig(3), getnetpath(3), rpcbind(3), rpc_clnt_auth(3), rpc_clnt_calls(3), rpc_clnt_create(3), rpc_svc_calls(3), rpc_svc_create(3), rpc_svc_err(3), rpc_svc_reg(3), rpc_xdr(3), xdr(3), netconfig(5)

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