get_myaddress


SYNOPSIS AND DESCRIPTION
       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.

       To take use of these routines, include the header file <rpc/rpc.h>.

       The prototypes below make use of the following types:

           typedef int bool_t;

           typedef bool_t (*xdrproc_t) (XDR *, void *,...);

           typedef bool_t (*resultproc_t) (caddr_t resp,
                                           struct sockaddr_in *raddr);

       See the header files for the declarations of the AUTH, CLIENT, SVCXPRT,
       and XDR types.

       void auth_destroy(AUTH *auth);

              A  macro that destroys the authentication information associated
              with auth.  Destruction usually involves deallocation of private
              data  structures.   The  use  of auth is undefined after calling
              auth_destroy().

       AUTH *authnone_create(void);

              Create and return  an  RPC  authentication  handle  that  passes
              nonusable  authentication information with each remote procedure
              call.  This is the default authentication used by RPC.

       AUTH *authunix_create(char *host, int uid, int gid,
                             int len, int *aup_gids);

              Create and return an RPC  authentication  handle  that  contains
              authentication  information.   The parameter host is the name of
              the machine on which the information was  created;  uid  is  the
              user's  user  ID;  gid  is  the user's current group ID; len and
              aup_gids refer to a counted array of groups to  which  the  user
              belongs.  It is easy to impersonate a user.

       AUTH *authunix_create_default(void);

              Calls authunix_create() with the appropriate parameters.

       int callrpc(char *host, unsigned long prognum,
                   unsigned long versnum, unsigned long procnum,
                   xdrproc_t inproc, char *in,
                   xdrproc_t outproc, char *out);

              as a transport; see clntudp_create() for restrictions.   You  do
              not  have  control of timeouts or authentication using this rou-
              tine.

       enum clnt_stat clnt_broadcast(unsigned long prognum,
                            unsigned long versnum, unsigned long procnum,
                            xdrproc_t inproc, char *in,
                            xdrproc_t outproc, char *out,
                            resultproc_t eachresult);

              Like callrpc(), except the call  message  is  broadcast  to  all
              locally  connected  broadcast  nets.   Each  time  it receives a
              response, this routine calls eachresult(), whose form is:

                  eachresult(char *out, struct sockaddr_in *addr);

              where out is the same as out passed to clnt_broadcast(),  except
              that the remote procedure's output is decoded there; addr points
              to the address of the machine that sent the results.  If eachre-
              sult()  returns  zero,  clnt_broadcast() waits for more replies;
              otherwise it returns with appropriate status.

              Warning: broadcast sockets are limited in size  to  the  maximum
              transfer  unit  of  the  data link.  For ethernet, this value is
              1500 bytes.

       enum clnt_stat clnt_call(CLIENT *clnt, unsigned long procnum,
                           xdrproc_t inproc, char *in,
                           xdrproc_t outproc, char *out,
                           struct timeval tout);

              A macro that calls the remote procedure procnum associated  with
              the  client  handle,  clnt, which is obtained with an RPC client
              creation routine such as clnt_create().  The parameter in is the
              address  of  the procedure's argument(s), and out is the address
              of where to place the result(s); inproc is used  to  encode  the
              procedure's parameters, and outproc is used to decode the proce-
              dure's results; tout is the time allowed  for  results  to  come
              back.

       clnt_destroy(CLIENT *clnt);

              A macro that destroys the client's RPC handle.  Destruction usu-
              ally involves deallocation of private data structures, including
              clnt   itself.    Use   of   clnt  is  undefined  after  calling
              clnt_destroy().   If  the  RPC  library  opened  the  associated
              socket,  it  will  close it also.  Otherwise, the socket remains
              open.

       CLIENT *clnt_create(char *host, unsigned long prog,
                           unsigned long vers, char *proto);

              Generic client creation routine.  host identifies  the  name  of
              the  remote  host  where the server is located.  proto indicates
              client object.  req indicates the type of operation, and info is
              a  pointer  to  the information.  For both UDP and TCP, the sup-
              ported values of req and their argument types and what  they  do
              are:

                  CLSET_TIMEOUT  struct timeval // set total timeout
                  CLGET_TIMEOUT  struct timeval // get total timeout

              Note:  if  you set the timeout using clnt_control(), the timeout
              parameter passed to clnt_call() will be ignored  in  all  future
              calls.

                  CLGET_SERVER_ADDR  struct sockaddr_in  // get server's address

              The following operations are valid for UDP only:

                  CLSET_RETRY_TIMEOUT  struct timeval // set the retry timeout
                  CLGET_RETRY_TIMEOUT  struct timeval // get the retry timeout

              The  retry  timeout  is  the  time  that "UDP RPC" waits for the
              server to reply before retransmitting the request.

       clnt_freeres(CLIENT * clnt, xdrproc_t outproc, char *out);

              A macro that frees any data allocated by the RPC/XDR system when
              it decoded the results of an RPC call.  The parameter out is the
              address of the results, and outproc is the XDR routine  describ-
              ing  the  results.  This routine returns one if the results were
              successfully freed, and zero otherwise.

       void clnt_geterr(CLIENT *clnt, struct rpc_err *errp);

              A macro that copies the error structure out of the client handle
              to the structure at address errp.

       void clnt_pcreateerror(char *s);

              Print  a  message  to standard error indicating why a client RPC
              handle could not be created.   The  message  is  prepended  with
              string  s  and a colon.  Used when a clnt_create(), clntraw_cre-
              ate(), clnttcp_create(), or clntudp_create() call fails.

       void clnt_perrno(enum clnt_stat stat);

              Print a message to standard error corresponding to the condition
              indicated by stat.  Used after callrpc().

       clnt_perror(CLIENT *clnt, char *s);

              Print  a  message  to  standard error indicating why an RPC call
              failed; clnt is the handle used to do the call.  The message  is
              prepended with string s and a colon.  Used after clnt_call().

       char *clnt_spcreateerror(char *s);
              The string ends with a NEWLINE.

              clnt_sperrno() is used instead of 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 printf(3), or if a message format dif-
              ferent than that supported  by  clnt_perrno()  is  to  be  used.
              Note:  unlike clnt_sperror() and clnt_spcreaterror(), clnt_sper-
              rno() returns pointer to static data, but the  result  will  not
              get overwritten on each call.

       char *clnt_sperror(CLIENT *rpch, char *s);

              Like clnt_perror(), except that (like clnt_sperrno()) it returns
              a string instead of printing to standard error.

              Bugs: returns pointer to static data that is overwritten on each
              call.

       CLIENT *clntraw_create(unsigned long prognum, unsigned long versnum);

              This  routine  creates  a  toy RPC client for the remote program
              prognum, version 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 svcraw_create().  This allows simulation of
              RPC and acquisition of RPC overheads, such as round trip  times,
              without  any  kernel interference.  This routine returns NULL if
              it fails.

       CLIENT *clnttcp_create(struct sockaddr_in *addr,
                       unsigned long prognum, unsigned long versnum,
                       int *sockp, unsigned int sendsz, unsigned int recvsz);

              This routine creates  an  RPC  client  for  the  remote  program
              prognum, version versnum; the client uses TCP/IP as a transport.
              The remote program is located at  Internet  address  *addr.   If
              addr->sin_port  is  zero, then it is set to the actual port that
              the remote program is listening on (the remote  portmap  service
              is  consulted  for  this information).  The parameter sockp is a
              socket; if it is RPC_ANYSOCK, then this routine opens a new  one
              and sets sockp.  Since TCP-based RPC uses buffered I/O, the user
              may specify the size of the send and receive  buffers  with  the
              parameters  sendsz  and  recvsz;  values of zero choose suitable
              defaults.  This routine returns NULL if it fails.

       CLIENT *clntudp_create(struct sockaddr_in *addr,
                       unsigned long prognum, unsigned long versnum,
                       struct timeval wait, int *sockp);

              This routine creates  an  RPC  client  for  the  remote  program
              prognum, version versnum; the client uses use UDP/IP as a trans-
              port.  The remote program is located at Internet  address  addr.
              If  addr->sin_port  is  zero, then it is set to actual port that

       CLIENT *clntudp_bufcreate(struct sockaddr_in *addr,
                   unsigned long prognum, unsigned long versnum,
                   struct timeval wait, int *sockp,
                   unsigned int sendsize, unsigned int recosize);

              This routine creates  an  RPC  client  for  the  remote  program
              prognum,  on versnum; the client uses use UDP/IP as a transport.
              The remote program is located  at  Internet  address  addr.   If
              addr->sin_port  is  zero, then it is set to actual port that the
              remote program is listening on (the remote  portmap  service  is
              consulted  for  this  information).   The  parameter  sockp is a
              socket; if it is RPC_ANYSOCK, then this routine opens a new  one
              and  sets  sockp.  The UDP transport resends the call message in
              intervals of 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 clnt_call().

              This allows the user to specify  the  maximum  packet  size  for
              sending and receiving UDP-based RPC messages.

       void get_myaddress(struct sockaddr_in *addr);

              Stuff  the  machine's  IP address into *addr, without consulting
              the library routines that deal with /etc/hosts.  The port number
              is always set to htons(PMAPPORT).

       struct pmaplist *pmap_getmaps(struct sockaddr_in *addr);

              A user interface to the portmap service, which returns a list of
              the current RPC program-to-port mappings on the host located  at
              IP  address  *addr.   This routine can return NULL.  The command
              rpcinfo -p uses this routine.

       unsigned short pmap_getport(struct sockaddr_in *addr,
                           unsigned long prognum, unsigned long versnum,
                           unsigned int protocol);

              A user interface to the portmap service, which returns the  port
              number  on  which  waits  a service that supports program number
              prognum, version versnum,  and  speaks  the  transport  protocol
              associated  with protocol.  The value of protocol is most likely
              IPPROTO_UDP or IPPROTO_TCP.  A return value of zero  means  that
              the mapping does not exist or that the RPC system failed to con-
              tact the remote portmap service.  In the latter case, the global
              variable rpc_createerr contains the RPC status.

       enum clnt_stat pmap_rmtcall(struct sockaddr_in *addr,
                           unsigned long prognum, unsigned long versnum,
                           unsigned long procnum,
                           xdrproc_t inproc, char *in,
                           xdrproc_t outproc, char *out,
                           struct timeval tout, unsigned long *portp);

              A user interface to the portmap service, which instructs portmap
              on the machine's portmap service.  The value of protocol is most
              likely IPPROTO_UDP or IPPROTO_TCP.  This routine returns one  if
              it  succeeds,  zero otherwise.  Automatically done by svc_regis-
              ter().

       bool_t pmap_unset(unsigned long prognum, unsigned long versnum);

              A user interface to the portmap service, which destroys all map-
              ping  between  the  triple  [prognum,versnum,*] and ports on the
              machine's portmap service.  This routine returns one if it  suc-
              ceeds, zero otherwise.

       int registerrpc(unsigned long prognum, unsigned long versnum,
                       unsigned long procnum, char *(*procname)(char *),
                       xdrproc_t inproc, xdrproc_t outproc);

              Register  procedure procname with the RPC service package.  If a
              request arrives for program prognum, version versnum, and proce-
              dure  procnum,  procname is called with a pointer to its parame-
              ter(s);  progname  should  return  a  pointer  to   its   static
              result(s); inproc is used to decode the parameters while outproc
              is used to encode the results.  This routine returns zero if the
              registration succeeded, -1 otherwise.

              Warning:  remote procedures registered in this form are accessed
              using the UDP/IP transport;  see  svcudp_create()  for  restric-
              tions.

       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  clnt_pcreateer-
              ror() to print the reason why.

       void svc_destroy(SVCXPRT *xprt);

              A  macro  that  destroys the RPC service transport handle, xprt.
              Destruction usually involves deallocation of private data struc-
              tures,  including  xprt  itself.  Use of xprt is undefined after
              calling this routine.

       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
              select(2) system call.  This is only of interest  if  a  service
              implementor  does  not  call  svc_run(), but rather does his own
              asynchronous event processing.  This variable is  read-only  (do
              not  pass  its  address  to select(2)!), yet it may change after
              calls to svc_getreqset() or any creation routines.

       int svc_fds;

              Similar to svc_fdset,  but  limited  to  32  descriptors.   This
              with  the  RPC service transport handle, xprt.  The parameter in
              is the address where the arguments will be placed; inproc is the
              XDR  routine used to decode the arguments.  This routine returns
              one if decoding succeeds, and zero otherwise.

       struct sockaddr_in *svc_getcaller(SVCXPRT *xprt);

              The approved way of getting the network address of the caller of
              a  procedure  associated  with the RPC service transport handle,
              xprt.

       void svc_getreqset(fd_set *rdfds);

              This routine is only of interest if a service  implementor  does
              not  call  svc_run(), but instead implements custom asynchronous
              event processing.  It is called when the select(2)  system  call
              has  determined  that  an  RPC  request  has arrived on some RPC
              socket(s); rdfds is the resultant read file descriptor bit mask.
              The  routine  returns when all sockets associated with the value
              of rdfds have been serviced.

       void svc_getreq(int rdfds);

              Similar to svc_getreqset(), but limited to 32 descriptors.  This
              interface is obsoleted by svc_getreqset().

       bool_t svc_register(SVCXPRT *xprt, unsigned long prognum,
                           unsigned long versnum,
                           void (*dispatch)(svc_req *, SVCXPRT *),
                           unsigned long protocol);

              Associates  prognum and versnum with the service dispatch proce-
              dure, dispatch.  If protocol is zero, the service is not  regis-
              tered  with the portmap service.  If protocol is nonzero, then a
              mapping   of   the    triple    [prognum,versnum,protocol]    to
              xprt->xp_port  is  established  with  the  local portmap service
              (generally protocol is zero, IPPROTO_UDP or  IPPROTO_TCP).   The
              procedure dispatch has the following form:

                  dispatch(struct svc_req *request, SVCXPRT *xprt);

              The  svc_register() routine returns one if it succeeds, and zero
              otherwise.

       void svc_run(void);

              This routine never  returns.   It  waits  for  RPC  requests  to
              arrive,  and  calls  the  appropriate  service  procedure  using
              svc_getreq() when one arrives.  This procedure is usually  wait-
              ing for a select(2) system call to return.

       bool_t svc_sendreply(SVCXPRT *xprt, xdrproc_t outproc, char *out);

              Called  by an RPC service's dispatch routine to send the results

              Called  by  a service dispatch routine that refuses to perform a
              remote procedure call due to an authentication error.

       void svcerr_decode(SVCXPRT *xprt);

              Called by a service dispatch routine  that  cannot  successfully
              decode its parameters.  See also svc_getargs().

       void svcerr_noproc(SVCXPRT *xprt);

              Called by a service dispatch routine that does not implement the
              procedure number that the caller requests.

       void svcerr_noprog(SVCXPRT *xprt);

              Called when the desired program is not registered with  the  RPC
              package.  Service implementors usually do not need this routine.

       void svcerr_progvers(SVCXPRT *xprt);

              Called  when  the desired version of a program is not registered
              with the RPC package.  Service implementors usually do not  need
              this routine.

       void svcerr_systemerr(SVCXPRT *xprt);

              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 rou-
              tine.

       void svcerr_weakauth(SVCXPRT *xprt);

              Called by a service dispatch routine that refuses to  perform  a
              remote procedure call due to insufficient authentication parame-
              ters.  The routine calls svcerr_auth(xprt, AUTH_TOOWEAK).

       SVCXPRT *svcfd_create(int fd, unsigned int sendsize,
                             unsigned int recvsize);

              Create a service on top of any open descriptor.  Typically, this
              descriptor  is  a connected socket for a stream protocol such as
              TCP.  sendsize and recvsize indicate  sizes  for  the  send  and
              receive buffers.  If they are zero, a reasonable default is cho-
              sen.

       SVCXPRT *svcraw_create(void);

              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 clntraw_create().  This rou-
              tine allows simulation of RPC and acquisition of  RPC  overheads
              and xprt->xp_port is the transport's port number.  This  routine
              returns  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.

       SVCXPRT *svcudp_bufcreate(int sock, unsigned int sendsize,
                                 unsigned int recosize);

              This  routine  creates  a UDP/IP-based RPC service transport, to
              which it returns a pointer.  The transport  is  associated  with
              the  socket  sock, which may be 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, xprt->xp_sock is the transport's socket  descriptor,
              and  xprt->xp_port is the transport's port number.  This routine
              returns NULL if it fails.

              This allows the user to specify  the  maximum  packet  size  for
              sending and receiving UDP-based RPC messages.

       SVCXPRT *svcudp_create(int sock);

              This call is equivalent to svcudp_bufcreate(sock,SZ,SZ) for some
              default size SZ.

       bool_t xdr_accepted_reply(XDR *xdrs, struct accepted_reply *ar);

              Used for encoding RPC reply messages.  This  routine  is  useful
              for  users who wish to generate RPC-style messages without using
              the RPC package.

       bool_t xdr_authunix_parms(XDR *xdrs, struct authunix_parms *aupp);

              Used for describing UNIX credentials.  This  routine  is  useful
              for  users  who wish to generate these credentials without using
              the RPC authentication package.

       void xdr_callhdr(XDR *xdrs, struct rpc_msg *chdr);

              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.

       bool_t xdr_callmsg(XDR *xdrs, struct rpc_msg *cmsg);

              Used for describing RPC call messages.  This routine  is  useful
              for  users who wish to generate RPC-style messages without using
              the RPC package.

       bool_t xdr_opaque_auth(XDR *xdrs, struct opaque_auth *ap);

              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.

       bool_t xdr_rejected_reply(XDR *xdrs, struct rejected_reply *rr);

              Used for describing RPC reply messages.  This routine is  useful
              for  users who wish to generate RPC-style messages without using
              the RPC package.

       bool_t xdr_replymsg(XDR *xdrs, struct rpc_msg *rmsg);

              Used for describing RPC reply messages.  This routine is  useful
              for  users who wish to generate RPC style messages without using
              the RPC package.

       void xprt_register(SVCXPRT *xprt);

              After RPC service transport handles  are  created,  they  should
              register  themselves with the RPC service package.  This routine
              modifies the global variable svc_fds.  Service implementors usu-
              ally do not need this routine.

       void xprt_unregister(SVCXPRT *xprt);

              Before  an  RPC service transport handle is destroyed, it should
              unregister itself with the RPC service  package.   This  routine
              modifies the global variable svc_fds.  Service implementors usu-
              ally do not need this routine.

SEE ALSO
       xdr(3)
       The following manuals:
              Remote Procedure Calls: Protocol Specification
              Remote Procedure Call Programming Guide
              rpcgen Programming Guide
       RPC:  Remote  Procedure  Call  Protocol  Specification,  RFC 1050,  Sun
       Microsystems, Inc., USC-ISI.

COLOPHON
       This  page  is  part of release 3.35 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://man7.org/linux/man-pages/.



                                  2008-07-17                            RPC(3)
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