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document svcudp_create

.\"	@(#)rpc.3n	2.4 88/08/08 4.0 RPCSRC; from 1.19 88/06/24 SMI
.\"	$NetBSD: rpc_soc.3,v 1.11 2004/02/16 02:39:36 lukem Exp $
.\" Converted to mdoc by Thomas Klausner <wiz@NetBSD.org>
.\"
.Dd April 17, 2003
.Dt RPC_SOC 3
.Os
.Sh NAME
.Nm rpc_soc ,
.Nm auth_destroy ,
.Nm authnone_create ,
.Nm authunix_create ,
.Nm authunix_create_default ,
.Nm callrpc ,
.Nm clnt_broadcast ,
.Nm clnt_call ,
.Nm clnt_control ,
.Nm clnt_create ,
.Nm clnt_destroy ,
.Nm clnt_freeres ,
.Nm clnt_geterr ,
.Nm clnt_pcreateerror ,
.Nm clnt_perrno ,
.Nm clnt_perror ,
.Nm clnt_spcreateerror ,
.Nm clnt_sperrno ,
.Nm clnt_sperror ,
.Nm clntraw_create ,
.Nm clnttcp_create ,
.Nm clntudp_bufcreate ,
.Nm clntudp_create ,
.Nm get_myaddress ,
.Nm pmap_getmaps ,
.Nm pmap_getport ,
.Nm pmap_rmtcall ,
.Nm pmap_set ,
.Nm pmap_unset ,
.Nm registerrpc ,
.Nm rpc_createerr ,
.Nm svc_destroy ,
.Nm svc_fds ,
.Nm svc_fdset ,
.Nm svc_getargs ,
.Nm svc_getcaller ,
.Nm svc_getreg ,
.Nm svc_getregset ,
.Nm svc_register ,
.Nm svc_run ,
.Nm svc_sendreply ,
.Nm svc_unregister ,
.Nm svcerr_auth ,
.Nm svcerr_decode ,
.Nm svcerr_noproc ,
.Nm svcerr_noprog ,
.Nm svcerr_progvers ,
.Nm svcerr_systemerr ,
.Nm svcerr_weakauth ,
.Nm svcfd_create ,
.Nm svcraw_create ,
.Nm xdr_accepted_reply ,
.Nm xdr_authunix_parms ,
.Nm xdr_callhdr ,
.Nm xdr_callmsg ,
.Nm xdr_opaque_auth ,
.Nm xdr_pmap ,
.Nm xdr_pmaplist ,
.Nm xdr_rejected_reply ,
.Nm xdr_replymsg ,
.Nm xprt_register ,
.Nm xprt_unregister
.Nd library routines for remote procedure calls
.Sh SYNOPSIS
.In rpc/rpc.h
.Ft void
.Fn auth_destroy "AUTH *auth"
.Ft AUTH *
.Fn authnone_create "void"
.Ft AUTH *
.Fn authunix_create "char *host" "int uid" "int gid" "int len" "int *aup_gids"
.Ft AUTH *
.Fn authunix_create_default "void"
.Ft int
.Fn callrpc "char *host" "u_long prognum" "u_long versnum" \
"u_long procnum" "xdrproc_t inproc" "char *in" "xdrproc_t outproc" "char *out"
.Ft enum clnt_stat
.Fn clnt_broadcast "u_long prognum" "u_long versnum" "u_long procnum" \
"xdrproc_t inproc" "char *in" "xdrproc_t outproc" "char *out" \
"resultproc_t eachresult"
.Ft enum clnt_stat
.Fn clnt_call "CLIENT *clnt" "u_long procnum" "xdrproc_t inproc" \
"char *in" "xdrproc_t outproc" "char *out" "struct timeval tout"
.Ft int
.Fn clnt_destroy "CLIENT *clnt"
.Ft CLIENT *
.Fn clnt_create "char *host" "u_long prog" "u_long vers" "char *proto"
.Ft bool_t
.Fn clnt_control "CLIENT *cl" "u_int req" "char *info"
.Ft int
.Fn clnt_freeres "CLIENT *clnt" "xdrproc_t outproc" "char *out"
.Ft void
.Fn clnt_geterr "CLIENT *clnt" "struct rpc_err errp"
.Ft void
.Fn clnt_pcreateerror "char *s"
.Ft void
.Fn clnt_perrno "enum clnt_stat stat"
.Ft int
.Fn clnt_perror "CLIENT *clnt" "char *s"
.Ft char *
.Fn clnt_spcreateerror "const char *s"
.Ft char *
.Fn clnt_sperrno "enum clnt_stat stat"
.Ft char *
.Fn clnt_sperror "CLIENT *rpch" "char *s"
.Ft CLIENT *
.Fn clntraw_create "u_long prognum" "u_long versnum"
.Ft CLIENT *
.Fn clnttcp_create "struct sockaddr_in *addr" "u_long prognum" \
"u_long versnum" "int *sockp" "u_int sendsz" "u_int recvsz"
.Ft CLIENT *
.Fn clntudp_create "struct sockaddr_in *addr" "u_long prognum" \
"u_long versnum" "struct timeval wait" "int *sockp"
.Ft CLIENT *
.Fn clntudp_bufcreate "struct sockaddr_in *addr" "u_long prognum" \
"u_long versnum" "struct timeval wait" "int *sockp" \
"unsigned int sendsize" "unsigned int recosize"
.Ft int
.Fn get_myaddress "struct sockaddr_in *addr"
.Ft struct pmaplist *
.Fn pmap_getmaps "struct sockaddr_in *addr"
.Ft u_short
.Fn pmap_getport "struct sockaddr_in *addr" "u_long prognum" \
"u_long versnum" "u_long protocol"
.Ft enum clnt_stat
.Fo pmap_rmtcall
.Fa "struct sockaddr_in *addr"
.Fa "u_long prognum"
.Fa "u_long versnum"
.Fa "u_long procnum"
.Fa "xdrproc_t inproc"
.Fa "char *in"
.Fa "xdrpoc_t outproc"
.Fa "char *out"
.Fa "struct timeval tout"
.Fa "u_long *portp"
.Fc
.Ft int
.Fn pmap_set "u_long prognum" "u_long versnum" "int protocol" \
"int port"
.Ft int
.Fn pmap_unset "u_long prognum" "u_long versnum"
.Ft int
.Fn registerrpc "u_long prognum" "u_long versnum" "u_long procnum" \
"char *(*procname)()" "xdrproc_t inproc" "xdrproc_t outproc"
.Fd struct rpc_createerr rpc_createerr;
.Ft int
.Fn svc_destroy "SVCXPRT *xprt"
.Fd fd_set svc_fdset;
.Fd int svc_fds;
.Ft int
.Fn svc_freeargs "SVCXPRT *xprt" "xdrproc_t inproc" "char *in"
.Ft int
.Fn svc_getargs "SVCXPRT *xprt" "xdrproc_t inproc" "char *in"
.Ft struct sockaddr_in *
.Fn svc_getcaller "SVCXPRT *xprt"
.Ft int
.Fn svc_getreqset "fd_set *rdfds"
.Ft int
.Fn svc_getreq "int rdfds"
.Ft int
.Fn svc_register "SVCXPRT *xprt" "u_long prognum" "u_long versnum" \
"void (*dispatch)()" "u_long protocol"
.Ft int
.Fn svc_run "void"
.Ft int
.Fn svc_sendreply "SVCXPRT *xprt" "xdrproc_t outproc" "char *out"
.Ft void
.Fn svc_unregister "u_long prognum" "u_long versnum"
.Ft void
.Fn svcerr_auth "SVCXPRT *xprt" "enum auth_stat why"
.Ft void
.Fn svcerr_decode "SVCXPRT *xprt"
.Ft void
.Fn svcerr_noproc "SVCXPRT *xprt"
.Ft void
.Fn svcerr_noprog "SVCXPRT *xprt"
.Ft void
.Fn svcerr_progvers "SVCXPRT *xprt"
.Ft void
.Fn svcerr_systemerr "SVCXPRT *xprt"
.Ft void
.Fn svcerr_weakauth "SVCXPRT *xprt"
.Ft SVCXPRT *
.Fn svcraw_create "void"
.Ft SVCXPRT *
.Fn svctcp_create "int sock" "u_int send_buf_size" \
"u_int recv_buf_size"
.Ft SVCXPRT *
.Fn svcfd_create "int fd" "u_int sendsize" "u_int recvsize"
.Ft SVCXPRT *
.Fn svcudp_bufcreate "int sock" "u_int sendsize" "u_int recosize"
.Ft SVCXPRT *
.Fn svcudp_create "int sock"
.Ft int
.Fn xdr_accepted_reply "XDR *xdrs" "struct accepted_reply *ar"
.Ft int
.Fn xdr_authunix_parms "XDR *xdrs" "struct authunix_parms *aupp"
.Ft void
.Fn xdr_callhdr "XDR *xdrs" "struct rpc_msg *chdr"
.Ft int
.Fn xdr_callmsg "XDR *xdrs" "struct rpc_msg *cmsg"
.Ft int
.Fn xdr_opaque_auth "XDR *xdrs" "struct opaque_auth *ap"
.Ft int
.Fn xdr_pmap "XDR *xdrs" "struct pmap *regs"
.Ft int
.Fn xdr_pmaplist "XDR *xdrs" "struct pmaplist **rp"
.Ft int
.Fn xdr_rejected_reply "XDR *xdrs" "struct rejected_reply *rr"
.Ft int
.Fn xdr_replymsg "XDR *xdrs" "struct rpc_msg *rmsg"
.Ft void
.Fn xprt_register "SVCXPRT *xprt"
.Ft void
.Fn xprt_unregister "SVCXPRT *xprt"
.Sh DESCRIPTION
.Em "The svc and clnt functions described in this page are the old, TS-RPC"
.Em "interface to the XDR and RPC library, and exist for backward compatibility."
.Em "The new interface is described in the pages referenced from"
.Xr rpc 3 .
.Pp
These routines allow C programs to make procedure
calls on other machines across the network.
First, the client calls a procedure to send a
data packet to the server.
Upon receipt of the packet, the server calls a dispatch routine
to perform the requested service, and then sends back a
reply.
Finally, the procedure call returns to the client.
.\" XXX: NOTYET
.\".Pp
.\"Routines that are used for Secure RPC (DES authentication) are described in
.\".Xr rpc_secure 3 .
.\"Secure RPC can be used only if DES encryption is available.
.Pp
.Bl -tag -width xxx
.It Fn auth_destroy
A macro that destroys the authentication information associated with
.Fa auth .
Destruction usually involves deallocation of private data structures.
The use of
.Fa auth
is undefined after calling
.Fn auth_destroy .
.It Fn authnone_create
Create and returns an RPC authentication handle that passes nonusable
authentication information with each remote procedure call.
This is the default authentication used by RPC.
.It Fn authunix_create
Create and return an RPC authentication handle that contains
.\" XXX: .UX ?
authentication information.
The parameter
.Fa host
is the name of the machine on which the information was
created;
.Fa uid
is the user's user ID;
.Fa gid
is the user's current group id;
.Fa len
and
.Fa aup_gids
refer to a counted array of groups to which the user belongs.
It is easy to impersonate a user.
.It Fn authunix_create_default
Calls
.Fn authunix_create
with the appropriate parameters.
.It Fn callrpc
Call the remote procedure associated with
.Fa prognum ,
.Fa versnum ,
and
.Fa procnum
on the machine,
.Fa host .
The parameter
.Fa in
is the address of the procedure's argument(s), and
.Fa out
is the address of where to place the result(s);
.Fa inproc
is used to encode the procedure's parameters, and
.Fa outproc
is used to decode the procedure's results.
This routine returns zero if it succeeds, or the value of
.Va "enum clnt_stat"
cast to an integer if it fails.
The routine
.Fn clnt_perrno
is handy for translating failure statuses into messages.
.Pp
Warning: calling remote procedures with this routine
uses UDP/IP as a transport; see
.Fn clntudp_create
for restrictions.
You do not have control of timeouts or authentication using
this routine.
.It Fn clnt_broadcast
Like
.Fn callrpc ,
except the call message is broadcast to all locally
connected broadcast nets.
Each time it receives a response, this routine calls
.Fn eachresult ,
whose form is
.Ft int
.Fn eachresult "char *out" "struct sockaddr_in *addr"
where
.Fa out
is the same as
.Fa out
passed to
.Fn clnt_broadcast ,
except that the remote procedure's output is decoded there;
.Fa addr
points to the address of the machine that sent the results.
If
.Fn eachresult
returns zero,
.Fn clnt_broadcast
waits for more replies; otherwise it returns with appropriate
status.
.Pp
Warning: broadcast sockets are limited in size to the
maximum transfer unit of the data link.
For ethernet, this value is 1500 bytes.
.It Fn clnt_call
A macro that calls the remote procedure
.Fa procnum
associated with the client handle,
.Fa clnt ,
which is obtained with an RPC client creation routine such as
.Fn clnt_create .
The parameter
.Fa in
is the address of the procedure's argument(s), and
.Fa out
is the address of where to place the result(s);
.Fa inproc
is used to encode the procedure's parameters, and
.Fa outproc
is used to decode the procedure's results;
.Fa tout
is the time allowed for results to come back.
.It Fn clnt_destroy
A macro that destroys the client's RPC handle.
Destruction usually involves deallocation
of private data structures, including
.Fa clnt
itself.
Use of
.Fa clnt
is undefined after calling
.Fn clnt_destroy .
If the RPC library opened the associated socket, it will close it
also.
Otherwise, the socket remains open.
.It Fn clnt_create
Generic client creation routine.
.Fa host
identifies the name of the remote host where the server
is located.
.Fa proto
indicates which kind of transport protocol to use.
The currently supported values for this field are
.Dq udp
and
.Dq tcp .
Default timeouts are set, but can be modified using
.Fn clnt_control .
.Pp
.Em Warning :
Using UDP has its shortcomings.
Since UDP-based RPC messages can only hold up to 8 Kbytes of encoded
data, this transport cannot be used for procedures that take
large arguments or return huge results.
.It Fn clnt_control
A macro used to change or retrieve various information
about a client object.
.Fa req
indicates the type of operation, and
.Fa info
is a pointer to the information.
For both UDP and TCP the supported values of
.Fa req
and their argument types and what they do are:
.Bl -tag -width CLSET_RETRY_TIMEOUTX
.It CLSET_TIMEOUT
.Vt struct timeval ;
set total timeout.
.It CLGET_TIMEOUT
.Vt struct timeval ;
get total timeout.
.Pp
Note: if you set the timeout using
.Fn clnt_control ,
the timeout parameter passed to
.Fn clnt_call
will be ignored in all future calls.
.It CLGET_SERVER_ADDR
.Vt struct sockaddr_in ;
get server's address.
.El
.Pp
The following operations are valid for UDP only:
.Bl -tag -width CLSET_RETRY_TIMEOUT
.It CLSET_RETRY_TIMEOUT
.Vt struct timeval ;
set the retry timeout.
.It CLGET_RETRY_TIMEOUT
.Vt struct timeval ;
get the retry timeout.
.Pp
The retry timeout is the time that UDP RPC waits for the server to
reply before retransmitting the request.
.El
.It Fn clnt_freeres
A macro that frees any data allocated by the RPC/XDR system when it
decoded the results of an RPC call.
The parameter
.Fa out
is the address of the results, and
.Fa outproc
is the XDR routine describing the results.
This routine returns one if the results were successfully freed,
and zero otherwise.
.It Fn clnt_geterr
A macro that copies the error structure out of the client
handle to the structure at address
.Fa errp .
.It Fn clnt_pcreateerror
Print a message to standard error indicating why a client RPC handle
could not be created.
The message is prepended with string
.Fa s
and a colon.
A newline character is appended at the end of the message.
Used when a
.Fn clnt_create ,
.Fn clntraw_create ,
.Fn clnttcp_create ,
or
.Fn clntudp_create
call fails.
.It Fn clnt_perrno
Print a message to standard error corresponding
to the condition indicated by
.Fa stat .
A newline character is appended at the end of the message.
Used after
.Fn callrpc .
.It Fn clnt_perror
Print a message to standard error indicating why an RPC call failed;
.Fa clnt
is the handle used to do the call.
The message is prepended with string
.Fa s
and a colon.
A newline character is appended at the end of the message.
Used after
.Fn clnt_call .
.It Fn clnt_spcreateerror
Like
.Fn clnt_pcreateerror ,
except that it returns a string
instead of printing to the standard error.
.Pp
Bugs: returns pointer to static data that is overwritten
on each call.
.It Fn clnt_sperrno
Take the same arguments as
.Fn clnt_perrno ,
but instead of sending a message to the standard error
indicating why an RPC call failed, return a pointer to a string which
contains the message.
.Pp
.Fn clnt_sperrno
is used instead of
.Fn clnt_perrno
if the program does not have a standard error (as a program
running as a server quite likely does not), or if the
programmer does not want the message to be output with
.Xr printf 3 ,
or if a message format different than that supported by
.Fn clnt_perrno
is to be used.
Note: unlike
.Fn clnt_sperror
and
.Fn clnt_spcreateerror ,
.Fn clnt_sperrno
returns a pointer to static data, but the
result will not get overwritten on each call.
.It Fn clnt_sperror
Like
.Fn clnt_perror ,
except that (like
.Fn clnt_sperrno )
it returns a string instead of printing to standard error.
.Pp
Bugs: returns pointer to static data that is overwritten
on each call.
.It Fn clntraw_create
This routine creates a toy RPC client for the remote program
.Fa prognum ,
version
.Fa versnum .
The transport used to pass messages to the service is
actually a buffer within the process's address space, so the
corresponding RPC server should live in the same address space; see
.Fn svcraw_create .
This allows simulation of RPC and acquisition of RPC overheads, such
as round trip times, without any kernel interference.
This routine returns
.Dv NULL
if it fails.
.It Fn clnttcp_create
This routine creates an RPC client for the remote program
.Fa prognum ,
version
.Fa versnum ;
the client uses TCP/IP as a transport.
The remote program is located at Internet address
.Fa *addr .
If
.Fa addr-\*[Gt]sin_port
is zero, then it is set to the actual port that the remote
program is listening on (the remote
.Xr rpcbind 8
or
.Cm portmap
service is consulted for this information).
The parameter
.Fa sockp
is a socket; if it is
.Dv RPC_ANYSOCK ,
then this routine opens a new one and sets
.Fa sockp .
Since TCP-based RPC uses buffered I/O ,
the user may specify the size of the send and receive buffers
with the parameters
.Fa sendsz
and
.Fa recvsz ;
values of zero choose suitable defaults.
This routine returns
.Dv NULL
if it fails.
.It Fn clntudp_create
This routine creates an RPC client for the remote program
.Fa prognum ,
version
.Fa versnum ;
the client uses UDP/IP as a transport.
The remote program is located at Internet address
.Fa addr .
If
.Fa addr-\*[Gt]sin_port
is zero, then it is set to actual port that the remote
program is listening on (the remote
.Xr rpcbind 8
or
.Cm portmap
service is consulted for this information).
The parameter
.Fa sockp
is a socket; if it is
.Dv RPC_ANYSOCK ,
then this routine opens a new one and sets
.Fa sockp .
The UDP transport resends the call message in intervals of
.Fa wait
time until a response is received or until the call times out.
The total time for the call to time out is specified by
.Fa clnt_call .
.Pp
Warning: since UDP-based RPC messages can only hold up to 8 Kbytes
of encoded data, this transport cannot be used for procedures
that take large arguments or return huge results.
.It Fn clntudp_bufcreate
This routine creates an RPC client for the remote program
.Fa prognum ,
on
.Fa versnum ;
the client uses UDP/IP as a transport.
The remote program is located at Internet address
.Fa addr .
If
.Fa addr-\*[Gt]sin_port
is zero, then it is set to actual port that the remote
program is listening on (the remote
.Xr rpcbind 8
or
.Cm portmap
service is consulted for this information).
The parameter
.Fa sockp
is a socket; if it is
.Dv RPC_ANYSOCK ,
then this routine opens a new one and sets
.Fa sockp .
The UDP transport resends the call message in intervals of
.Fa wait
time until a response is received or until the call times out.
The total time for the call to time out is specified by
.Fa clnt_call .
.Pp
This allows the user to specify the maximum packet size for sending and
receiving UDP-based RPC messages.
.It Fn get_myaddress
Stuff the machine's IP address into
.Fa *addr ,
without consulting the library routines that deal with
.Pa /etc/hosts .
The port number is always set to
.Fn htons "PMAPPORT" .
Returns zero on success, non-zero on failure.
.It Fn pmap_getmaps
A user interface to the
.Xr rpcbind 8
service, which returns a list of the current RPC program-to-port
mappings on the host located at IP address
.Fa *addr .
This routine can return
.Dv NULL .
The command
.Dl Cm rpcinfo Fl p
uses this routine.
.It Fn pmap_getport
A user interface to the
.Xr rpcbind 8
service, which returns the port number
on which waits a service that supports program number
.Fa prognum ,
version
.Fa versnum ,
and speaks the transport protocol associated with
.Fa protocol .
The value of
.Fa protocol
is most likely
.Dv IPPROTO_UDP
or
.Dv IPPROTO_TCP .
A return value of zero means that the mapping does not exist
or that the RPC system failured to contact the remote
.Xr rpcbind 8
service.
In the latter case, the global variable
.Fn rpc_createerr
contains the RPC status.
.It Fn pmap_rmtcall
A user interface to the
.Xr rpcbind 8
service, which instructs
.Xr rpcbind 8
on the host at IP address
.Fa *addr
to make an RPC call on your behalf to a procedure on that host.
The parameter
.Fa *portp
will be modified to the program's port number if the
procedure succeeds.
The definitions of other parameters are discussed in
.Fn callrpc
and
.Fn clnt_call .
This procedure should be used for a
.Dq ping
and nothing else.
See also
.Fn clnt_broadcast .
.It Fn pmap_set
A user interface to the
.Xr rpcbind 8
service, which establishes a mapping between the triple
.Fa [ prognum ,
.Fa versnum ,
.Fa protocol ]
and
.Fa port
on the machine's
.Xr rpcbind 8
service.
The value of
.Fa protocol
is most likely
.Dv IPPROTO_UDP
or
.Dv IPPROTO_TCP .
This routine returns one if it succeeds, zero otherwise.
Automatically done by
.Fn svc_register .
.It Fn pmap_unset
A user interface to the
.Xr rpcbind 8
service, which destroys all mapping between the triple
.Fa [ prognum ,
.Fa versnum ,
.Fa * ]
and
.Fa ports
on the machine's
.Xr rpcbind 8
service.
This routine returns one if it succeeds, zero otherwise.
.It Fn registerrpc
Register procedure
.Fa procname
with the RPC service package.
If a request arrives for program
.Fa prognum ,
version
.Fa versnum ,
and procedure
.Fa procnum ,
.Fa procname
is called with a pointer to its parameter(s);
.Fa progname
should return a pointer to its static result(s);
.Fa inproc
is used to decode the parameters while
.Fa outproc
is used to encode the results.
This routine returns zero if the registration succeeded, \-1
otherwise.
.Pp
Warning: remote procedures registered in this form
are accessed using the UDP/IP transport; see
.Fn svcudp_bufcreate
for restrictions.
.It struct rpc_createerr rpc_createerr ;
A global variable whose value is set by any RPC
client creation routine that does not succeed.
Use the routine
.Fn clnt_pcreateerror
to print the reason why.
.It Fn svc_destroy
A macro that destroys the RPC service transport handle,
.Fa xprt .
Destruction usually involves deallocation
of private data structures, including
.Fa xprt
itself.
Use of
.Fa xprt
is undefined after calling this routine.
.It fd_set svc_fdset ;
A global variable reflecting the RPC service side's read file
descriptor bit mask; it is suitable as a parameter to the
.Xr select 2
system call.
This is only of interest if a service implementor does not call
.Fn svc_run ,
but rather does his own asynchronous event processing.
This variable is read-only (do not pass its address to
.Xr select 2 ! ) ,
yet it may change after calls to
.Fn svc_getreqset
or any creation routines.
.It int svc_fds;
Similar to
.Fn svc_fedset ,
but limited to 32 descriptors.
This interface is obsoleted by
.Fn svc_fdset .
.It Fn svc_freeargs
A macro that frees any data allocated by the RPC/XDR
system when it decoded the arguments to a service procedure using
.Fn svc_getargs .
This routine returns 1 if the results were successfully freed,
and zero otherwise.
.It Fn svc_getargs
A macro that decodes the arguments of an RPC request associated with
the RPC service transport handle,
.Fa xprt .
The parameter
.Fa in
is the address where the arguments will be placed;
.Fa inproc
is the XDR routine used to decode the arguments.
This routine returns one if decoding succeeds, and zero otherwise.
.It Fn svc_getcaller
The approved way of getting the network address of the caller
of a procedure associated with the RPC service transport handle,
.Fa xprt .
.It Fn svc_getreqset
This routine is only of interest if a service implementor
does not call
.Fn svc_run ,
but instead implements custom asynchronous event processing.
It is called when the
.Xr select 2
system call has determined that an RPC request has arrived on some
RPC socket(s) ;
.Fa rdfds
is the resultant read file descriptor bit mask.
The routine returns when all sockets associated with the
value of
.Fa rdfds
have been serviced.
.It Fn svc_getreq
Similar to
.Fn svc_getreqset ,
but limited to 32 descriptors.
This interface is obsoleted by
.Fn svc_getreqset .
.It Fn svc_register
Associates
.Fa prognum
and
.Fa versnum
with the service dispatch procedure,
.Fa dispatch .
If
.Fa protocol
is zero, the service is not registered with the
.Xr rpcbind 8
service.
If
.Fa protocol
is non-zero, then a mapping of the triple
.Fa [ prognum ,
.Fa versnum ,
.Fa protocol ]
to
.Fa xprt-\*[Gt]xp_port
is established with the local
.Xr rpcbind 8
service (generally
.Fa protocol
is zero,
.Dv IPPROTO_UDP
or
.Dv IPPROTO_TCP ) .
The procedure
.Fa dispatch
has the following form:
.Ft int
.Fn dispatch "struct svc_req *request" "SVCXPRT *xprt" .
.Pp
The
.Fn svc_register
routine returns one if it succeeds, and zero otherwise.
.It Fn svc_run
This routine never returns.
It waits for RPC requests to arrive, and calls the appropriate service
procedure using
.Fn svc_getreq
when one arrives.
This procedure is usually waiting for a
.Xr select 2
system call to return.
.It Fn svc_sendreply
Called by an RPC service's dispatch routine to send the results of a
remote procedure call.
The parameter
.Fa xprt
is the request's associated transport handle;
.Fa outproc
is the XDR routine which is used to encode the results; and
.Fa out
is the address of the results.
This routine returns one if it succeeds, zero otherwise.
.It Fn svc_unregister
Remove all mapping of the double
.Fa [ prognum ,
.Fa versnum ]
to dispatch routines, and of the triple
.Fa [ prognum ,
.Fa versnum ,
.Fa * ]
to port number.
.It Fn svcerr_auth
Called by a service dispatch routine that refuses to perform
a remote procedure call due to an authentication error.
.It Fn svcerr_decode
Called by a service dispatch routine that cannot successfully
decode its parameters.
See also
.Fn svc_getargs .
.It Fn svcerr_noproc
Called by a service dispatch routine that does not implement
the procedure number that the caller requests.
.It Fn svcerr_noprog
Called when the desired program is not registered with the RPC
package.
Service implementors usually do not need this routine.
.It Fn svcerr_progvers
Called when the desired version of a program is not registered
with the RPC package.
Service implementors usually do not need this routine.
.It Fn svcerr_systemerr
Called by a service dispatch routine when it detects a system error
not covered by any particular protocol.
For example, if a service can no longer allocate storage,
it may call this routine.
.It Fn svcerr_weakauth
Called by a service dispatch routine that refuses to perform
a remote procedure call due to insufficient
authentication parameters.
The routine calls
.Fn svcerr_auth "xprt" "AUTH_TOOWEAK" .
.It Fn svcraw_create
This routine creates a toy RPC service transport, to which it returns
a pointer.
The transport is really a buffer within the process's address space,
so the corresponding RPC client should live in the same address space;
see
.Fn clntraw_create .
This routine allows simulation of RPC and acquisition of RPC overheads
(such as round trip times), without any kernel interference.
This routine returns
.Dv NULL
if it fails.
.It Fn svctcp_create
This routine creates a TCP/IP-based RPC service transport, to which it
returns a pointer.
The transport is associated with the socket
.Fa sock ,
which may be
.Dv RPC_ANYSOCK ,
in which case a new socket is created.
If the socket is not bound to a local TCP
port, then this routine binds it to an arbitrary port.
Upon completion,
.Fa xprt-\*[Gt]xp_sock
is the transport's socket descriptor, and
.Fa xprt-\*[Gt]xp_port
is the transport's port number.
This routine returns
.Dv NULL
if it fails.
Since TCP-based RPC uses buffered I/O ,
users may specify the size of buffers; values of zero
choose suitable defaults.
.It Fn svcfd_create
Create a service on top of any open descriptor.
Typically, this descriptor is a connected socket
for a stream protocol such as TCP.
.Fa sendsize
and
.Fa recvsize
indicate sizes for the send and receive buffers.
If they are zero, a reasonable default is chosen.
.It Fn svcudp_bufcreate
This routine creates a UDP/IP-based RPC
service transport, to which it returns a pointer.
The transport is associated with the socket
.Fa sock ,
which may be
.Dv RPC_ANYSOCK ,
in which case a new socket is created.
If the socket is not bound to a local UDP
port, then this routine binds it to an arbitrary port.
Upon completion,
.Fa xprt-\*[Gt]xp_sock
is the transport's socket descriptor, and
.Fa xprt-\*[Gt]xp_port
is the transport's port number.
This routine returns
.Dv NULL
if it fails.
.Pp
This allows the user to specify the maximum packet size for sending and
receiving UDP-based RPC messages.
.It Fn svcudp_create
This acts as
.Fn svcudp_bufcreate with
predefined sizes for the maximum packet sizes.
.It Fn xdr_accepted_reply
Used for encoding RPC reply messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xdr_authunix_parms
Used for describing UNIX credentials.
This routine is useful for users who wish to generate these
credentials without using the RPC authentication package.
.It Fn xdr_callhdr
Used for describing RPC call header messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xdr_callmsg
Used for describing RPC call messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xdr_opaque_auth
Used for describing RPC authentication information messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xdr_pmap
Used for describing parameters to various
.Xr rpcbind 8
procedures, externally.
This routine is useful for users who wish to generate
these parameters without using the
.Em pmap
interface.
.It Fn xdr_pmaplist
Used for describing a list of port mappings, externally.
This routine is useful for users who wish to generate
these parameters without using the
.Em pmap
interface.
.It Fn xdr_rejected_reply
Used for describing RPC reply messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xdr_replymsg
Used for describing RPC reply messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
.It Fn xprt_register
After RPC service transport handles are created,
they should register themselves with the RPC service package.
This routine modifies the global variable
.Va svc_fds .
Service implementors usually do not need this routine.
.It Fn xprt_unregister
Before an RPC service transport handle is destroyed,
it should unregister itself with the RPC service package.
This routine modifies the global variable
.Va svc_fds .
Service implementors usually do not need this routine.
.El
.Sh SEE ALSO
.\".Xr rpc_secure 3 ,
.Xr xdr 3
.Pp
The following manuals:
.Rs
.%B Remote Procedure Calls: Protocol Specification
.Re
.Rs
.%B Remote Procedure Call Programming Guide
.Re
.Rs
.%B rpcgen Programming Guide
.Re
.Pp
.Rs
.%A Sun Microsystems, Inc., USC-ISI
.%T "RPC: Remote Procedure Call Protocol Specification"
.%J RFC
.%V 1050
.Re