Exemplo n.º 1
0
bool_t
pmap_set(u_long program, u_long version, int protocol, int port)
{
	bool_t rslt;
	struct netbuf *na;
	struct netconfig *nconf;
	char buf[32];

	if ((protocol != IPPROTO_UDP) && (protocol != IPPROTO_TCP)) {
		return (FALSE);
	}
	nconf = __rpc_getconfip(protocol == IPPROTO_UDP ? "udp" : "tcp");
	if (nconf == NULL) {
		return (FALSE);
	}
	snprintf(buf, sizeof buf, "0.0.0.0.%d.%d", 
	    (((u_int32_t)port) >> 8) & 0xff, port & 0xff);
	na = uaddr2taddr(nconf, buf);
	if (na == NULL) {
		freenetconfigent(nconf);
		return (FALSE);
	}
	rslt = rpcb_set((rpcprog_t)program, (rpcvers_t)version, nconf, na);
	free(na);
	freenetconfigent(nconf);
	return (rslt);
}
Exemplo n.º 2
0
/*
 * Returns 1 if the given address is bound for the given addr & transport
 * For all error cases, we assume that the address is bound
 * Returns 0 for success.
 */
static bool_t
check_bound(struct fdlist *fdl, char *uaddr)
{
	int fd;
	struct netbuf *na;
	int ans;

	if (fdl->check_binding == FALSE)
		return (TRUE);

	na = uaddr2taddr(fdl->nconf, uaddr);
	if (!na)
		return (TRUE); /* punt, should never happen */

	fd = __rpc_nconf2fd(fdl->nconf);
	if (fd < 0) {
		free(na->buf);
		free(na);
		return (TRUE);
	}

	ans = bind(fd, (struct sockaddr *)na->buf, na->len);

	close(fd);
	free(na->buf);
	free(na);

	return (ans == 0 ? FALSE : TRUE);
}
Exemplo n.º 3
0
/*
 * Find a server address that can be used by `caller' to contact
 * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
 * non-NULL, it is used instead of `caller' as a hint suggesting
 * the best address (e.g. the `r_addr' field of an rpc, which
 * contains the rpcbind server address that the caller used).
 *
 * Returns the best server address as a malloc'd "universal address"
 * string which should be freed by the caller. On error, returns NULL.
 */
char *
addrmerge(struct netbuf *caller, const char *serv_uaddr, const char *clnt_uaddr,
	  const char *netid)
{
	struct ifaddrs *ifap, *ifp = NULL, *bestif;
	struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
	struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
	struct sockaddr_storage ss;
	struct netconfig *nconf;
	char *caller_uaddr = NULL;
	const char *hint_uaddr = NULL;
	char *ret = NULL;
	int bestif_goodness;

#ifdef ND_DEBUG
	if (debugging)
		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
		    clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
#endif
	caller_sa = caller->buf;
	if ((nconf = rpcbind_get_conf(netid)) == NULL)
		goto freeit;
	if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
		goto freeit;

	/*
	 * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
	 * address family is different from that of the caller.
	 */
	hint_sa = NULL;
	if (clnt_uaddr != NULL) {
		hint_uaddr = clnt_uaddr;
		if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
			goto freeit;
		hint_sa = hint_nbp->buf;
	}
	if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
		hint_uaddr = caller_uaddr;
		hint_sa = caller->buf;
	}

#ifdef ND_DEBUG
	if (debugging)
		fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
#endif
	/* Local caller, just return the server address. */
	if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
	    strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
		ret = strdup(serv_uaddr);
		goto freeit;
	}

	if (getifaddrs(&ifp) < 0)
		goto freeit;

	/*
	 * Loop through all interface addresses.  We are listening to an address
	 * if any of the following are true:
	 * a) It's a loopback address
	 * b) It was specified with the -h command line option
	 * c) There were no -h command line options.
	 *
	 * Among addresses on which we are listening, choose in order of
	 * preference an address that is:
	 *
	 * a) Equal to the hint
	 * b) A link local address with the same scope ID as the client's
	 *    address, if the client's address is also link local
	 * c) An address on the same subnet as the client's address
	 * d) A non-localhost, non-p2p address
	 * e) Any usable address
	 */
	bestif = NULL;
	bestif_goodness = 0;
	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
		ifsa = ifap->ifa_addr;
		ifmasksa = ifap->ifa_netmask;

		/* Skip addresses where we don't listen */
		if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
		    !(ifap->ifa_flags & IFF_UP))
			continue;

		if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
			continue;

		if ((hint_sa->sa_family == AF_INET) &&
		    ((((struct sockaddr_in*)hint_sa)->sin_addr.s_addr == 
		      ((struct sockaddr_in*)ifsa)->sin_addr.s_addr))) {
			const int goodness = 4;

			bestif_goodness = goodness;
			bestif = ifap;
			goto found;
		}
#ifdef INET6
		if ((hint_sa->sa_family == AF_INET6) &&
		    (0 == memcmp(&((struct sockaddr_in6*)hint_sa)->sin6_addr,
				 &((struct sockaddr_in6*)ifsa)->sin6_addr,
				 sizeof(struct in6_addr))) &&
		    (((struct sockaddr_in6*)hint_sa)->sin6_scope_id ==
		    (((struct sockaddr_in6*)ifsa)->sin6_scope_id))) {
			const int goodness = 4;

			bestif_goodness = goodness;
			bestif = ifap;
			goto found;
		}
		if (hint_sa->sa_family == AF_INET6) {
			/*
			 * For v6 link local addresses, if the caller is on
			 * a link-local address then use the scope id to see
			 * which one.
			 */
			if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
			    IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
				if (SA2SIN6(ifsa)->sin6_scope_id ==
				    SA2SIN6(caller_sa)->sin6_scope_id) {
					const int goodness = 3;

					if (bestif_goodness < goodness) {
						bestif = ifap;
						bestif_goodness = goodness;
					}
				}
			}
		}
#endif /* INET6 */
		if (0 == bitmaskcmp(hint_sa, ifsa, ifmasksa)) {
			const int goodness = 2;

			if (bestif_goodness < goodness) {
				bestif = ifap;
				bestif_goodness = goodness;
			}
		}
		if (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
			const int goodness = 1;

			if (bestif_goodness < goodness) {
				bestif = ifap;
				bestif_goodness = goodness;
			}
		}
		if (bestif == NULL)
			bestif = ifap;
	}
	if (bestif == NULL)
		goto freeit;

found:
	/*
	 * Construct the new address using the address from
	 * `bestif', and the port number from `serv_uaddr'.
	 */
	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
	if (serv_nbp == NULL)
		goto freeit;
	serv_sa = serv_nbp->buf;

	memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
	switch (ss.ss_family) {
	case AF_INET:
		SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
		break;
#ifdef INET6
	case AF_INET6:
		SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
		break;
#endif
	}
	tbuf.len = ss.ss_len;
	tbuf.maxlen = sizeof(ss);
	tbuf.buf = &ss;
	ret = taddr2uaddr(nconf, &tbuf);

freeit:
	if (caller_uaddr != NULL)
		free(caller_uaddr);
	if (hint_nbp != NULL) {
		free(hint_nbp->buf);
		free(hint_nbp);
	}
	if (serv_nbp != NULL) {
		free(serv_nbp->buf);
		free(serv_nbp);
	}
	if (ifp != NULL)
		freeifaddrs(ifp);

#ifdef ND_DEBUG
	if (debugging)
		fprintf(stderr, "addrmerge: returning %s\n", ret);
#endif
	return ret;
}
Exemplo n.º 4
0
/*
 * rpc_broadcast_exp()
 *
 * prog      - program number
 * vers      - version number
 * proc      - procedure number
 * xargs     - xdr routine for args
 * argsp     - pointer to args
 * xresults  - xdr routine for results
 * resultsp  - pointer to results
 * eachresult - call with each result obtained
 * inittime  - how long to wait initially
 * waittime  - maximum time to wait
 * nettype   - transport type
 */
enum clnt_stat
rpc_broadcast_exp(rpcprog_t prog, rpcvers_t vers, rpcproc_t proc,
    xdrproc_t xargs, caddr_t argsp, xdrproc_t xresults, caddr_t resultsp,
    resultproc_t eachresult, int inittime, int waittime,
    const char *nettype)
{
	enum clnt_stat	stat = RPC_SUCCESS; /* Return status */
	XDR 		xdr_stream; /* XDR stream */
	XDR 		*xdrs = &xdr_stream;
	struct rpc_msg	msg;	/* RPC message */
	struct timeval	t;
	char 		*outbuf = NULL;	/* Broadcast msg buffer */
	char		*inbuf = NULL; /* Reply buf */
	int		inlen;
	u_int 		maxbufsize = 0;
	AUTH 		*sys_auth = authunix_create_default();
	u_int		i;
	void		*handle;
	char		uaddress[1024];	/* A self imposed limit */
	char		*uaddrp = uaddress;
	int 		pmap_reply_flag; /* reply recvd from PORTMAP */
	/* An array of all the suitable broadcast transports */
	struct {
		int fd;		/* File descriptor */
		int af;
		int proto;
		struct netconfig *nconf; /* Netconfig structure */
		u_int asize;	/* Size of the addr buf */
		u_int dsize;	/* Size of the data buf */
		struct sockaddr_storage raddr; /* Remote address */
		broadlist_t nal;
	} fdlist[MAXBCAST];
	struct pollfd pfd[MAXBCAST];
	size_t fdlistno = 0;
	struct r_rpcb_rmtcallargs barg;	/* Remote arguments */
	struct r_rpcb_rmtcallres bres; /* Remote results */
	size_t outlen;
	struct netconfig *nconf;
	int msec;
	int pollretval;
	int fds_found;

#ifdef PORTMAP
	size_t outlen_pmap = 0;
	u_long port;		/* Remote port number */
	int pmap_flag = 0;	/* UDP exists ? */
	char *outbuf_pmap = NULL;
	struct rmtcallargs barg_pmap;	/* Remote arguments */
	struct rmtcallres bres_pmap; /* Remote results */
	u_int udpbufsz = 0;
#endif				/* PORTMAP */

	if (sys_auth == NULL) {
		return (RPC_SYSTEMERROR);
	}
	/*
	 * initialization: create a fd, a broadcast address, and send the
	 * request on the broadcast transport.
	 * Listen on all of them and on replies, call the user supplied
	 * function.
	 */

	if (nettype == NULL)
		nettype = "datagram_n";
	if ((handle = __rpc_setconf(nettype)) == NULL) {
		AUTH_DESTROY(sys_auth);
		return (RPC_UNKNOWNPROTO);
	}
	while ((nconf = __rpc_getconf(handle)) != NULL) {
		int fd;
		struct __rpc_sockinfo si;

		if (nconf->nc_semantics != NC_TPI_CLTS)
			continue;
		if (fdlistno >= MAXBCAST)
			break;	/* No more slots available */
		if (!__rpc_nconf2sockinfo(nconf, &si))
			continue;

		TAILQ_INIT(&fdlist[fdlistno].nal);
		if (__rpc_getbroadifs(si.si_af, si.si_proto, si.si_socktype, 
		    &fdlist[fdlistno].nal) == 0)
			continue;

		fd = _socket(si.si_af, si.si_socktype, si.si_proto);
		if (fd < 0) {
			stat = RPC_CANTSEND;
			continue;
		}
		fdlist[fdlistno].af = si.si_af;
		fdlist[fdlistno].proto = si.si_proto;
		fdlist[fdlistno].fd = fd;
		fdlist[fdlistno].nconf = nconf;
		fdlist[fdlistno].asize = __rpc_get_a_size(si.si_af);
		pfd[fdlistno].events = POLLIN | POLLPRI |
			POLLRDNORM | POLLRDBAND;
		pfd[fdlistno].fd = fdlist[fdlistno].fd = fd;
		fdlist[fdlistno].dsize = __rpc_get_t_size(si.si_af, si.si_proto,
							  0);

		if (maxbufsize <= fdlist[fdlistno].dsize)
			maxbufsize = fdlist[fdlistno].dsize;

#ifdef PORTMAP
		if (si.si_af == AF_INET && si.si_proto == IPPROTO_UDP) {
			udpbufsz = fdlist[fdlistno].dsize;
			if ((outbuf_pmap = malloc(udpbufsz)) == NULL) {
				_close(fd);
				stat = RPC_SYSTEMERROR;
				goto done_broad;
			}
			pmap_flag = 1;
		}
#endif				/* PORTMAP */
		fdlistno++;
	}

	if (fdlistno == 0) {
		if (stat == RPC_SUCCESS)
			stat = RPC_UNKNOWNPROTO;
		goto done_broad;
	}
	if (maxbufsize == 0) {
		if (stat == RPC_SUCCESS)
			stat = RPC_CANTSEND;
		goto done_broad;
	}
	inbuf = malloc(maxbufsize);
	outbuf = malloc(maxbufsize);
	if ((inbuf == NULL) || (outbuf == NULL)) {
		stat = RPC_SYSTEMERROR;
		goto done_broad;
	}

	/* Serialize all the arguments which have to be sent */
	(void) gettimeofday(&t, NULL);
	msg.rm_xid = __RPC_GETXID(&t);
	msg.rm_direction = CALL;
	msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
	msg.rm_call.cb_prog = RPCBPROG;
	msg.rm_call.cb_vers = RPCBVERS;
	msg.rm_call.cb_proc = RPCBPROC_CALLIT;
	barg.prog = prog;
	barg.vers = vers;
	barg.proc = proc;
	barg.args.args_val = argsp;
	barg.xdr_args = xargs;
	bres.addr = uaddrp;
	bres.results.results_val = resultsp;
	bres.xdr_res = xresults;
	msg.rm_call.cb_cred = sys_auth->ah_cred;
	msg.rm_call.cb_verf = sys_auth->ah_verf;
	xdrmem_create(xdrs, outbuf, maxbufsize, XDR_ENCODE);
	if ((!xdr_callmsg(xdrs, &msg)) ||
	    (!xdr_rpcb_rmtcallargs(xdrs,
	    (struct rpcb_rmtcallargs *)(void *)&barg))) {
		stat = RPC_CANTENCODEARGS;
		goto done_broad;
	}
	outlen = xdr_getpos(xdrs);
	xdr_destroy(xdrs);

#ifdef PORTMAP
	/* Prepare the packet for version 2 PORTMAP */
	if (pmap_flag) {
		msg.rm_xid++;	/* One way to distinguish */
		msg.rm_call.cb_prog = PMAPPROG;
		msg.rm_call.cb_vers = PMAPVERS;
		msg.rm_call.cb_proc = PMAPPROC_CALLIT;
		barg_pmap.prog = prog;
		barg_pmap.vers = vers;
		barg_pmap.proc = proc;
		barg_pmap.args_ptr = argsp;
		barg_pmap.xdr_args = xargs;
		bres_pmap.port_ptr = &port;
		bres_pmap.xdr_results = xresults;
		bres_pmap.results_ptr = resultsp;
		xdrmem_create(xdrs, outbuf_pmap, udpbufsz, XDR_ENCODE);
		if ((! xdr_callmsg(xdrs, &msg)) ||
		    (! xdr_rmtcall_args(xdrs, &barg_pmap))) {
			stat = RPC_CANTENCODEARGS;
			goto done_broad;
		}
		outlen_pmap = xdr_getpos(xdrs);
		xdr_destroy(xdrs);
	}
#endif				/* PORTMAP */

	/*
	 * Basic loop: broadcast the packets to transports which
	 * support data packets of size such that one can encode
	 * all the arguments.
	 * Wait a while for response(s).
	 * The response timeout grows larger per iteration.
	 */
	for (msec = inittime; msec <= waittime; msec += msec) {
		struct broadif *bip;

		/* Broadcast all the packets now */
		for (i = 0; i < fdlistno; i++) {
			if (fdlist[i].dsize < outlen) {
				stat = RPC_CANTSEND;
				continue;
			}
			for (bip = TAILQ_FIRST(&fdlist[i].nal); bip != NULL;
			     bip = TAILQ_NEXT(bip, link)) {
				void *addr;

				addr = &bip->broadaddr;

				__rpc_broadenable(fdlist[i].af, fdlist[i].fd,
				    bip);

				/*
				 * Only use version 3 if lowvers is not set
				 */

				if (!__rpc_lowvers)
					if (_sendto(fdlist[i].fd, outbuf,
					    outlen, 0, (struct sockaddr*)addr,
					    (size_t)fdlist[i].asize) !=
					    outlen) {
#ifdef RPC_DEBUG
						perror("sendto");
#endif
						warnx("clnt_bcast: cannot send "
						      "broadcast packet");
						stat = RPC_CANTSEND;
						continue;
					}
#ifdef RPC_DEBUG
				if (!__rpc_lowvers)
					fprintf(stderr, "Broadcast packet sent "
						"for %s\n",
						 fdlist[i].nconf->nc_netid);
#endif
#ifdef PORTMAP
				/*
				 * Send the version 2 packet also
				 * for UDP/IP
				 */
				if (pmap_flag &&
				    fdlist[i].proto == IPPROTO_UDP) {
					if (_sendto(fdlist[i].fd, outbuf_pmap,
					    outlen_pmap, 0, addr,
					    (size_t)fdlist[i].asize) !=
						outlen_pmap) {
						warnx("clnt_bcast: "
						    "Cannot send broadcast packet");
						stat = RPC_CANTSEND;
						continue;
					}
				}
#ifdef RPC_DEBUG
				fprintf(stderr, "PMAP Broadcast packet "
					"sent for %s\n",
					fdlist[i].nconf->nc_netid);
#endif
#endif				/* PORTMAP */
			}
			/* End for sending all packets on this transport */
		}	/* End for sending on all transports */

		if (eachresult == NULL) {
			stat = RPC_SUCCESS;
			goto done_broad;
		}

		/*
		 * Get all the replies from these broadcast requests
		 */
	recv_again:

		switch (pollretval = _poll(pfd, fdlistno, msec)) {
		case 0:		/* timed out */
			stat = RPC_TIMEDOUT;
			continue;
		case -1:	/* some kind of error - we ignore it */
			goto recv_again;
		}		/* end of poll results switch */

		for (i = fds_found = 0;
		     i < fdlistno && fds_found < pollretval; i++) {
			bool_t done = FALSE;

			if (pfd[i].revents == 0)
				continue;
			else if (pfd[i].revents & POLLNVAL) {
				/*
				 * Something bad has happened to this descri-
				 * ptor. We can cause _poll() to ignore
				 * it simply by using a negative fd.  We do that
				 * rather than compacting the pfd[] and fdlist[]
				 * arrays.
				 */
				pfd[i].fd = -1;
				fds_found++;
				continue;
			} else
				fds_found++;
#ifdef RPC_DEBUG
			fprintf(stderr, "response for %s\n",
				fdlist[i].nconf->nc_netid);
#endif
		try_again:
			inlen = _recvfrom(fdlist[i].fd, inbuf, fdlist[i].dsize,
			    0, (struct sockaddr *)(void *)&fdlist[i].raddr,
			    &fdlist[i].asize);
			if (inlen < 0) {
				if (errno == EINTR)
					goto try_again;
				warnx("clnt_bcast: Cannot receive reply to "
					"broadcast");
				stat = RPC_CANTRECV;
				continue;
			}
			if (inlen < sizeof (u_int32_t))
				continue; /* Drop that and go ahead */
			/*
			 * see if reply transaction id matches sent id.
			 * If so, decode the results. If return id is xid + 1
			 * it was a PORTMAP reply
			 */
			if (*((u_int32_t *)(void *)(inbuf)) ==
			    *((u_int32_t *)(void *)(outbuf))) {
				pmap_reply_flag = 0;
				msg.acpted_rply.ar_verf = _null_auth;
				msg.acpted_rply.ar_results.where =
					(caddr_t)(void *)&bres;
				msg.acpted_rply.ar_results.proc =
					(xdrproc_t)xdr_rpcb_rmtcallres;
#ifdef PORTMAP
			} else if (pmap_flag &&
				*((u_int32_t *)(void *)(inbuf)) ==
				*((u_int32_t *)(void *)(outbuf_pmap))) {
				pmap_reply_flag = 1;
				msg.acpted_rply.ar_verf = _null_auth;
				msg.acpted_rply.ar_results.where =
					(caddr_t)(void *)&bres_pmap;
				msg.acpted_rply.ar_results.proc =
					(xdrproc_t)xdr_rmtcallres;
#endif				/* PORTMAP */
			} else
				continue;
			xdrmem_create(xdrs, inbuf, (u_int)inlen, XDR_DECODE);
			if (xdr_replymsg(xdrs, &msg)) {
				if ((msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
				    (msg.acpted_rply.ar_stat == SUCCESS)) {
					struct netbuf taddr, *np;
					struct sockaddr_in *sin;

#ifdef PORTMAP
					if (pmap_flag && pmap_reply_flag) {
						sin = (struct sockaddr_in *)
						    (void *)&fdlist[i].raddr;
						sin->sin_port =
						    htons((u_short)port);
						taddr.len = taddr.maxlen = 
						    fdlist[i].raddr.ss_len;
						taddr.buf = &fdlist[i].raddr;
						done = (*eachresult)(resultsp,
						    &taddr, fdlist[i].nconf);
					} else {
#endif				/* PORTMAP */
#ifdef RPC_DEBUG
						fprintf(stderr, "uaddr %s\n",
						    uaddrp);
#endif
						np = uaddr2taddr(
						    fdlist[i].nconf, uaddrp);
						done = (*eachresult)(resultsp,
						    np, fdlist[i].nconf);
						free(np);
#ifdef PORTMAP
					}
#endif				/* PORTMAP */
				}
				/* otherwise, we just ignore the errors ... */
			}
			/* else some kind of deserialization problem ... */

			xdrs->x_op = XDR_FREE;
			msg.acpted_rply.ar_results.proc = (xdrproc_t) xdr_void;
			(void) xdr_replymsg(xdrs, &msg);
			(void) (*xresults)(xdrs, resultsp);
			XDR_DESTROY(xdrs);
			if (done) {
				stat = RPC_SUCCESS;
				goto done_broad;
			} else {
				goto recv_again;
			}
		}		/* The recv for loop */
	}			/* The giant for loop */

done_broad:
	free(inbuf);
	free(outbuf);
#ifdef PORTMAP
	free(outbuf_pmap);
#endif				/* PORTMAP */
	for (i = 0; i < fdlistno; i++) {
		(void)_close(fdlist[i].fd);
		__rpc_freebroadifs(&fdlist[i].nal);
	}
	AUTH_DESTROY(sys_auth);
	(void) __rpc_endconf(handle);

	return (stat);
}
Exemplo n.º 5
0
char *
addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
	  char *netid)
{
	struct ifaddrs *ifap, *ifp, *bestif;
#ifdef INET6
	struct sockaddr_in6 *servsin6, *sin6mask, *clntsin6, *ifsin6, *realsin6;
	struct sockaddr_in6 *newsin6;
#endif
	struct sockaddr_in *servsin, *sinmask, *clntsin, *newsin, *ifsin;
	struct netbuf *serv_nbp, *clnt_nbp = NULL, tbuf;
	struct sockaddr *serv_sa;
	struct sockaddr *clnt_sa;
	struct sockaddr_storage ss;
	struct netconfig *nconf;
	struct sockaddr *clnt = caller->buf;
	char *ret = NULL;

#ifdef INET6
	servsin6 = ifsin6 = newsin6 = NULL;	/* XXXGCC -Wuninitialized */
#endif
	servsin = newsin = NULL;		/* XXXGCC -Wuninitialized */

#ifdef RPCBIND_DEBUG
	if (debugging)
		fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
		    clnt_uaddr, netid);
#endif
	nconf = getnetconfigent(netid);
	if (nconf == NULL)
		return NULL;

	/*
	 * Local merge, just return a duplicate.
	 */
	if (clnt_uaddr != NULL && strncmp(clnt_uaddr, "0.0.0.0.", 8) == 0)
		return strdup(clnt_uaddr);

	serv_nbp = uaddr2taddr(nconf, serv_uaddr);
	if (serv_nbp == NULL)
		return NULL;

	serv_sa = (struct sockaddr *)serv_nbp->buf;
	if (clnt_uaddr != NULL) {
		clnt_nbp = uaddr2taddr(nconf, clnt_uaddr);
		if (clnt_nbp == NULL) {
			free(serv_nbp);
			return NULL;
		}
		clnt_sa = (struct sockaddr *)clnt_nbp->buf;
		if (clnt_sa->sa_family == AF_LOCAL) {
			free(serv_nbp);
			free(clnt_nbp);
			free(clnt_sa);
			return strdup(serv_uaddr);
		}
	} else {
		clnt_sa = (struct sockaddr *)
		    malloc(sizeof (struct sockaddr_storage));
		memcpy(clnt_sa, clnt, clnt->sa_len);
	}

	if (getifaddrs(&ifp) < 0) {
		free(serv_nbp);
		free(clnt_sa);
		if (clnt_nbp != NULL)
			free(clnt_nbp);
		return 0;
	}

	/*
	 * Loop through all interfaces. For each interface, see if the
	 * network portion of its address is equal to that of the client.
	 * If so, we have found the interface that we want to use.
	 */
	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
		    !(ifap->ifa_flags & IFF_UP))
			continue;

		switch (clnt->sa_family) {
		case AF_INET:
			/*
			 * realsin: address that recvfrom gave us.
			 * ifsin: address of interface being examined.
			 * clntsin: address that client want us to contact
			 *           it on
			 * servsin: local address of RPC service.
			 * sinmask: netmask of this interface
			 * newsin: initially a copy of clntsin, eventually
			 *         the merged address
			 */
			servsin = (struct sockaddr_in *)serv_sa;
			clntsin = (struct sockaddr_in *)clnt_sa;
			sinmask = (struct sockaddr_in *)ifap->ifa_netmask;
			newsin = (struct sockaddr_in *)&ss;
			ifsin = (struct sockaddr_in *)ifap->ifa_addr;
			if (!bitmaskcmp(&ifsin->sin_addr, &clntsin->sin_addr,
			    &sinmask->sin_addr, sizeof (struct in_addr))) {
				goto found;
			}
			break;
#ifdef INET6
		case AF_INET6:
			/*
			 * realsin6: address that recvfrom gave us.
			 * ifsin6: address of interface being examined.
			 * clntsin6: address that client want us to contact
			 *           it on
			 * servsin6: local address of RPC service.
			 * sin6mask: netmask of this interface
			 * newsin6: initially a copy of clntsin, eventually
			 *          the merged address
			 *
			 * For v6 link local addresses, if the client contacted
			 * us via a link-local address, and wants us to reply
			 * to one, use the scope id to see which one.
			 */
			realsin6 = (struct sockaddr_in6 *)clnt;
			ifsin6 = (struct sockaddr_in6 *)ifap->ifa_addr;
			in6_fillscopeid(ifsin6);
			clntsin6 = (struct sockaddr_in6 *)clnt_sa;
			servsin6 = (struct sockaddr_in6 *)serv_sa;
			sin6mask = (struct sockaddr_in6 *)ifap->ifa_netmask;
			newsin6 = (struct sockaddr_in6 *)&ss;
			if (IN6_IS_ADDR_LINKLOCAL(&ifsin6->sin6_addr) &&
			    IN6_IS_ADDR_LINKLOCAL(&realsin6->sin6_addr) &&
			    IN6_IS_ADDR_LINKLOCAL(&clntsin6->sin6_addr)) {
				if (ifsin6->sin6_scope_id !=
				    realsin6->sin6_scope_id)
					continue;
				goto found;
			}
			if (!bitmaskcmp(&ifsin6->sin6_addr,
			    &clntsin6->sin6_addr, &sin6mask->sin6_addr,
			    sizeof (struct in6_addr)))
				goto found;
			break;
#endif
		default:
			goto freeit;
		}
	}
	/*
	 * Didn't find anything. Get the first possibly useful interface,
	 * preferring "normal" interfaces to point-to-point and loopback
	 * ones.
	 */
	bestif = NULL;
	for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
		if (ifap->ifa_addr->sa_family != clnt->sa_family ||
		    !(ifap->ifa_flags & IFF_UP))
			continue;
		if (!(ifap->ifa_flags & IFF_LOOPBACK) &&
		    !(ifap->ifa_flags & IFF_POINTOPOINT)) {
			bestif = ifap;
			break;
		}
		if (bestif == NULL)
			bestif = ifap;
		else if ((bestif->ifa_flags & IFF_LOOPBACK) &&
		    !(ifap->ifa_flags & IFF_LOOPBACK))
			bestif = ifap;
	}
	ifap = bestif;
found:
	switch (clnt->sa_family) {
	case AF_INET:
		memcpy(newsin, ifap->ifa_addr, clnt_sa->sa_len);
		newsin->sin_port = servsin->sin_port;
		tbuf.len = clnt_sa->sa_len;
		tbuf.maxlen = sizeof (struct sockaddr_storage);
		tbuf.buf = newsin;
		break;				
#ifdef INET6
	case AF_INET6:
		assert(newsin6);
		memcpy(newsin6, ifsin6, clnt_sa->sa_len);
		newsin6->sin6_port = servsin6->sin6_port;
		tbuf.maxlen = sizeof (struct sockaddr_storage);
		tbuf.len = clnt_sa->sa_len;
		tbuf.buf = newsin6;
		break;
#endif
	default:
		goto freeit;
	}
	if (ifap != NULL)
		ret = taddr2uaddr(nconf, &tbuf);
freeit:
	freenetconfigent(nconf);
	free(serv_sa);
	free(serv_nbp);
	if (clnt_sa != NULL)
		free(clnt_sa);
	if (clnt_nbp != NULL)
		free(clnt_nbp);
	freeifaddrs(ifp);

#ifdef RPCBIND_DEBUG
	if (debugging)
		fprintf(stderr, "addrmerge: returning %s\n", ret);
#endif
	return ret;
}