netdir_options man page on SmartOS

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       netdir,	  netdir_getbyname,    netdir_getbyaddr,   netdir_free,	  net‐
       dir_options, taddr2uaddr, uaddr2taddr,  netdir_perror,  netdir_sperror,
       netdir_mergeaddr - generic transport name-to-address translation

       cc [ flag... ] file... -lnsl [ library...]
       #include <netdir.h>

       int netdir_getbyname(struct netconfig  *config,
	    struct nd_hostserv *service, struct nd_addrlist **addrs);

       int netdir_getbyaddr(struct netconfig  *config,
	    struct nd_hostservlist **service, struct netbuf  *netaddr);

       void netdir_free(void *ptr, int struct_type);

       int netdir_options(struct netconfig  *config, int option, int fildes,
	    char *pointer_to_args);

       char *taddr2uaddr(struct netconfig *config, struct netbuf *addr);

       struct netbuf *uaddr2taddr(struct netconfig *config, char *uaddr);

       void netdir_perror(char *s);

       char *netdir_sperror(void);

       The  netdir  functions  provide a generic interface for name-to-address
       mapping that will work with all	transport  protocols.  This  interface
       provides	 a  generic  way  for  programs	 to convert transport specific
       addresses into common structures and back again. The  netconfig	struc‐
       ture,  described on the netconfig(4) manual page, identifies the trans‐

       The netdir_getbyname() function maps the machine name and service  name
       in  the	nd_hostserv structure to a collection of addresses of the type
       understood by the transport identified in the netconfig structure. This
       function returns all addresses that are valid for that transport in the
       nd_addrlist structure. The nd_hostserv structure contains the following

	 char *h_host;	    /* host name */
	 char *h_serv;	    /* service name */

       The nd_addrlist structure contains the following members:

	 int  n_cnt;	   /* number of addresses */
	 struct netbuf *n_addrs;

       The  netdir_getbyname()	function accepts some special-case host names.
       The host names are defined in <netdir.h>. The  currently	 defined  host
       names are:

			    Represents	the  address  to  which local programs
			    will bind their endpoints.	HOST_SELF differs from
			    the	 host  name provided by gethostname(3C), which
			    represents the address to  which  remote  programs
			    will bind their endpoints.

			    Represents	any  host accessible by this transport
			    provider. HOST_ANY allows applications to  specify
			    a required service without specifying a particular
			    host name.

			    Represents the host address that can  be  used  to
			    connect to the local host.

			    Represents the address for all hosts accessible by
			    this transport provider.  Network requests to this
			    address are received by all machines.

       All fields of the nd_hostserv structure must be initialized.

       To find the address of a given host and service on all available trans‐
       ports, call the netdir_getbyname() function with each struct  netconfig
       structure returned by getnetconfig(3NSL).

       The  netdir_getbyaddr()	function  maps addresses to service names. The
       function returns service, a list of host and service pairs  that	 yield
       these  addresses.  If  more  than one tuple of host and service name is
       returned, the first tuple  contains  the	 preferred  host  and  service

	 struct nd_hostservlist {
	    int	 *h_cnt;		  /* number of hostservs found */
	    struct hostserv *h_hostservs;

       The netdir_free() structure is used to free the structures allocated by
       the name to address translation functions. The ptr parameter points  to
       the  structure  that has to be freed. The parameter struct_type identi‐
       fies the structure:

	 struct netbuf		  ND_ADDR
	 struct nd_addrlist	  ND_ADDRLIST
	 struct hostserv	  ND_HOSTSERV
	 struct nd_hostservlist	  ND_HOSTSERVLIST

       The free() function is used to free the universal address  returned  by
       the taddr2uaddr() function.

       The netdir_options() function is used to do all transport-specific set‐
       ups and option management. fildes is the	 associated  file  descriptor.
       option,	fildes, and pointer_to_args are passed to the netdir_options()
       function for the transport specified in config.	Currently four	values
       are defined for option:


       The specific actions of each option follow.

				Sets the transport provider up to allow broad‐
				cast  if  the  transport  supports  broadcast.
				fildes	is  a  file descriptor into the trans‐
				port, that is,	the  result  of	 a  t_open  of
				/dev/udp.  pointer_to_args  is	not  used.  If
				this completes, broadcast  operations  can  be
				performed on file descriptor fildes.

				Allows	the  application to bind to a reserved
				port if that concept exists for the  transport
				provider. fildes is an unbound file descriptor
				into  the  transport.  If  pointer_to_args  is
				NULL,  fildes  is bound to a reserved port. If
				pointer_to_args	 is  a	pointer	 to  a	netbuf
				structure,  an	attempt is made to bind to any
				reserved port on the specified address.

				Used to verify that the address corresponds to
				a reserved port if that concept exists for the
				transport  provider.  fildes  is   not	 used.
				pointer_to_args	 is  a	pointer	 to  a	netbuf
				structure  that	 contains  the	address.  This
				option returns 0 only if the address specified
				in pointer_to_args is reserved.

				Used to take a ``local	address''  such	 as  a	  TCP  address	and  return  a	``real
				address'' to which client  machines  can  con‐
				nect. fildes is not used. pointer_to_args is a
				pointer to a struct nd_mergearg which has  the
				following members:

				  char s_uaddr;	 /* server's universal address */
				  char c_uaddr;	 /* client's universal address */
				  char m_uaddr;	 /* the result */

				If s_uaddr is an address such as,
				and the call is successful m_uaddr is  set  to
				an  address  such  as  For
				most  transports,  m_uaddr  is	identical   to

       If  a  transport	 provider  does	 not support an option, netdir_options
       returns -1 and the error message can be printed through netdir_perror()
       or netdir_sperror().

       The  taddr2uaddr()  and	uaddr2taddr()  functions  support  translation
       between universal addresses and TLI  type  netbufs.  The	 taddr2uaddr()
       function	 takes a struct netbuf data structure and returns a pointer to
       a string that contains the universal address. It returns	 NULL  if  the
       conversion  is  not  possible.  This  is	 not a fatal condition as some
       transports do not support a universal address form.

       The uaddr2taddr() function is the reverse of  the  taddr2uaddr()	 func‐
       tion. It returns the struct netbuf data structure for the given univer‐
       sal address.

       The netdir_perror() function prints an error message in standard output
       that  states  the cause of a name-to-address mapping failure. The error
       message is preceded by the string given as an argument.

       The netdir_sperror() function returns a string with  an	error  message
       that states the cause of a name-to-address mapping failure.

       The  netdir_sperror() function returns a pointer to a buffer which con‐
       tains the error message string. The buffer is overwritten on each call.
       In  multithreaded  applications,	 this buffer is implemented as thread-
       specific data.

       The netdir_getbyaddr() function returns 0 on  success  and  a  non-zero
       value on failure.

       See attributes(5) for descriptions of the following attributes:

       │MT-Level       │ Safe		 │

       gethostname(3C),	 getnetconfig(3NSL),  getnetpath(3NSL),	 netconfig(4),

				 Dec 25, 2013			  NETDIR(3NSL)

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