ONC+ Developer's Guide

rpcbind Protocol

rpcbind maps RPC program and version numbers to universal addresses, thus making dynamic binding of remote programs possible.

rpcbind is bound to a well-known address of each supported transport, and other programs register their dynamically allocated transport addresses with it. rpcbind then makes those addresses publicly available. Universal addresses are string representations of the transport-dependent address. They are defined by the addressing authority of the given transport.

rpcbind also aids in broadcast RPC. RPC programs have different addresses on different machines, so direct broadcasts to all these programs are not possible. rpcbind, however, has a well-known address. So, to broadcast to a given program, the client sends its message to the rpcbind process on the machine it chooses to reach. rpcbind picks up the broadcast and calls the local service specified by the client. When rpcbind gets a reply from the local service, it passes the reply on to the client.

The following code example shows the rpcbind Protocol Specification in RPC Language.


Example B–5 rpcbind Protocol Specification in RPC Language

/*
 * rpcb_prot.x
 * RPCBIND protocol in rpc language
 */
/*
 * A mapping of (program, version, network ID) to universal
address
 */
struct rpcb {
	rpcproc_t r_prog;           /* program number */
	rpcvers_t r_vers;           /* version number */
	string r_netid<>;               /* network id */
	string r_addr<>;                /* universal address */
	string r_owner<>;               /* owner of this service */ };
/* A list of mappings */
struct rpcblist {
	rpcb rpcb_map;
	struct rpcblist *rpcb_next;
};
 
/* Arguments of remote calls */
struct rpcb_rmtcallargs {
	rpcprog_t prog;             /* program number */
	rpcvers_t vers;             /* version number */
	rpcproc_t proc;             /* procedure number */
	opaque args<>;                  /* argument */
};
 
/* Results of the remote call */
struct rpcb_rmtcallres {
	string addr<>;                  /* remote universal address */
	opaque results<>;               /* result */
};
 
/*
 * rpcb_entry contains a merged address of a service on a
particular
 * transport, plus associated netconfig information. A list of
 * rpcb_entrys is returned by RPCBPROC_GETADDRLIST. See
netconfig.h
 * for values used in r_nc_* fields.
 */
struct rpcb_entry {
	string          r_maddr<>;      /* merged address of service */
	string          r_nc_netid<>;   /* netid field */
	unsigned int   r_nc_semantics; /* semantics of transport */
	string          r_nc_protofmly<>; /* protocol family */
	string          r_nc_proto<>;   /* protocol name */
};
 
/* A list of addresses supported by a service. */
struct rpcb_entry_list {
	rpcb_entry rpcb_entry_map;
	struct rpcb_entry_list *rpcb_entry_next;
};
 
typedef rpcb_entry_list *rpcb_entry_list_ptr;
 
/* rpcbind statistics */
const rpcb_highproc_2 = RPCBPROC_CALLIT;
const rpcb_highproc_3 = RPCBPROC_TADDR2UADDR;
const rpcb_highproc_4 = RPCBPROC_GETSTAT;
const RPCBSTAT_HIGHPROC = 13;  /* # of procs in rpcbind V4 plus
one */
const RPCBVERS_STAT = 3;  /* provide only for rpcbind V2, V3 and
V4 */
const RPCBVERS_4_STAT = 2;
const RPCBVERS_3_STAT = 1;
const RPCBVERS_2_STAT = 0;
 
/* Link list of all the stats about getport and getaddr */
struct rpcbs_addrlist {
	rpcprog_t prog;
	rpcvers_t vers;
	int success;
	int failure;
	string netid<>;
	struct rpcbs_addrlist *next;
};
 
/* Link list of all the stats about rmtcall */
struct rpcbs_rmtcalllist {
	rpcprog_t prog;
	rpcvers_t vers;
	rpcproc_t proc;
	int success;
	int failure;
	int indirect;   /* whether callit or indirect */
	string netid<>;
	struct rpcbs_rmtcalllist *next;
};
 
typedef int rpcbs_proc[RPCBSTAT_HIGHPROC];
typedef rpcbs_addrlist *rpcbs_addrlist_ptr;
typedef rpcbs_rmtcalllist *rpcbs_rmtcalllist_ptr;
 
struct rpcb_stat {
	rpcbs_proc              info;
	int                     setinfo;
	int                     unsetinfo;
	rpcbs_addrlist_ptr      addrinfo;
	rpcbs_rmtcalllist_ptr   rmtinfo;
};
 
/*
 * One rpcb_stat structure is returned for each version of rpcbind
 * being monitored.
 */
typedef rpcb_stat rpcb_stat_byvers[RPCBVERS_STAT];
/* rpcbind procedures */
program RPCBPROG {
	version RPCBVERS {
		void
		RPCBPROC_NULL(void) = 0;
 
		/*
		 * Registers the tuple [r_prog, r_vers, r_addr, r_owner,
 
		 * r_netid]. The rpcbind server accepts requests for this
		 * procedure on only the loopback transport for security
		 * reasons. Returns TRUE if successful, FALSE on failure.
		 */
		bool
		RPCBPROC_SET(rpcb) = 1;
 
		/*
		 * Unregisters the tuple [r_prog, r_vers, r_owner, r_netid].
 
		 * If vers is zero, all versions are
unregistered. The rpcbind
		 * server accepts requests for this procedure on only the
		 * loopback transport for security reasons.  Returns TRUE if
		 * successful, FALSE on failure.
		 */
		bool
		RPCBPROC_UNSET(rpcb) = 2;
 
		/*
		 * Returns the universal address where the triple [r_prog,
 
		 * r_vers, r_netid] is registered.  If r_addr specified,
		 * return a universal address merged on r_addr. Ignores
		 * r_owner. Returns FALSE on failure.
		 */
		string
		RPCBPROC_GETADDR(rpcb) = 3;
 
		/* Returns a list of all mappings. */
 
	rpcblist
		RPCBPROC_DUMP(void) = 4;
 
		/*
		 * Calls the procedure on the remote machine.  If it is not
 
		 * registered, this procedure IS quiet; that is, it DOES NOT
		 * return error information.
		 */
		rpcb_rmtcallres
		RPCBPROC_CALLIT(rpcb_rmtcallargs) = 5;
 
		/*
		 * Returns the time on the rpcbind server's system.
 
		 */
		unsigned int
		RPCBPROC_GETTIME(void) = 6;
 
		struct netbuf
		RPCBPROC_UADDR2TADDR(string) = 7;
 

		string
		RPCBPROC_TADDR2UADDR(struct netbuf) = 8;
 
		} = 3;
		version RPCBVERS4 {
		bool
		RPCBPROC_SET(rpcb) = 1;
 
		bool
		RPCBPROC_UNSET(rpcb) = 2;
 
		string
		RPCBPROC_GETADDR(rpcb) = 3;
 
		rpcblist_ptr
		RPCBPROC_DUMP(void) = 4;
 
		/*
		 * NOTE: RPCBPROC_BCAST has the same functionality as CALLIT;
 
		 * the new name is
intended to indicate that this procedure
		 * should be used for broadcast RPC, and RPCBPROC_INDIRECT
		 * should be used for indirect calls.
		 */
		rpcb_rmtcallres
		RPCBPROC_BCAST(rpcb_rmtcallargs) = RPCBPROC_CALLIT;
 
		unsigned int
		RPCBPROC_GETTIME(void) = 6;
 
		struct netbuf
		RPCBPROC_UADDR2TADDR(string) = 7;
 

		string
		RPCBPROC_TADDR2UADDR(struct netbuf) = 8;
 

		/*
		 * Same as RPCBPROC_GETADDR except that if the given version
 
		 * number is not available, the address is not returned.
		 */
		string
		RPCBPROC_GETVERSADDR(rpcb) = 9;
 

		/*
		 * Calls the procedure on the remote machine.  If it is not
		 * registered, this procedure IS NOT quiet; that is, it DOES
		 * return error information.
		 */
		rpcb_rmtcallres
		RPCBPROC_INDIRECT(rpcb_rmtcallargs) = 10;
 
		/*
		 * Same as RPCBPROC_GETADDR except that it returns a list of
 
		 * addresses registered for the combination (prog, vers).
		 */
		rpcb_entry_list_ptr
		RPCBPROC_GETADDRLIST(rpcb) = 11;
 
		/*
		 * Returns statistics about the rpcbind server's activity.
 
		 */
		rpcb_stat_byvers
		RPCBPROC_GETSTAT(void) = 12;
	} = 4;
} = 100000;