freebsd-dev/usr.sbin/ypbind/ypbind.c
Bill Paul b2845e83db This commit adds support to ypbind(8) for binding to non-local servers.
The standard SunOS ypbind(8) (and, until now, the FreeBSD ypbind)
only selects servers based on whether or not they respond to clnt_broadcast().
Ypbind(8) broadcasts to the YPPROC_DOMAIN_NONACK procedure and waits
for answers; whichever server answers first is the one ypbind uses
for the local client binding.

This mechanism fails when binding across subnets is desired. In order
for a client on one subnet to bind to a server on another subnet, the
gateway(s) between the client and server must be configured to forward
broadcasts. If this is not possible, then a slave server must be
installed on the remote subnet. If this is also not possible, you
have to force the client to bind to the remote server with ypset(8).

Unfortunately, this last option is less than ideal. If the remote
server becomes unavailable, ypbind(8) will lose its binding and
revert to its broadcast-based search behavior. Even if there are
other servers available, or even if the original server comes back
up, ypbind(8) will not be able to create a new binding since all
the servers are on remote subnets where its broadcasts won't be heard.
If the administrator isn't around to run ypset(8) again, the system
is hosed.

In some Linux NIS implementations, there exists a yp.conf file where
you can explicitly specify a server address and avoid the use of
ypbind altogether. This is not desireable since it removes the
possibility of binding to an alternate server in the event that the
one specified in yp.conf crashes.

Some people have mentioned to me how they though the 'restricted mode'
operation (using the -S flag) could be used as a solution for this
problem since it allows one to specify a list of servers. In fact,
this is not the case: the -S flag just tells ypbind(8) that when it
listens for replies to its broadcasts, it should only honor them if
the replying hosts appear in the specified restricted list.

This behavior has now been changed. If you use the -m flag in conjunction
with the -S flag, ypbind(8) will use a 'many-cast' instead of a broadcast
for choosing a server. In many-cast mode, ypbind(8) will transmit directly
to the YPPROC_DOMAIN_NONACK procedure of all the servers specified in
the restricted mode list and then wait for a reply. As with the broadcast
method, whichever server from the list answers first is used for the
local binding. All other behavior is the same: ypbind(8) continues
to ping its bound server every 60 seconds to insure it's still alive
and will many-cast again if the server fails to respond. The code used
to achieve this is in yp_ping.c; it includes a couple of modified RPC
library routines.

Note that it is not possible to use this mechanism without using
the restricted list since we need to know the addresses of the available
NIS servers ahead of time in order to transmit to them.

Most-recently-requested by: Tom Samplonius
1997-05-25 19:49:33 +00:00

1025 lines
25 KiB
C

/*
* Copyright (c) 1992/3 Theo de Raadt <deraadt@fsa.ca>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef LINT
static char rcsid[] = "$Id: ypbind.c,v 1.24 1997/04/10 14:18:03 wpaul Exp $";
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <syslog.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <dirent.h>
#include <netdb.h>
#include <string.h>
#include <rpc/rpc.h>
#include <rpc/xdr.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/pmap_clnt.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_rmt.h>
#include <unistd.h>
#include <stdlib.h>
#include <rpcsvc/yp.h>
struct dom_binding{};
#include <rpcsvc/ypclnt.h>
#include "yp_ping.h"
#ifndef BINDINGDIR
#define BINDINGDIR "/var/yp/binding"
#endif
#ifndef YPBINDLOCK
#define YPBINDLOCK "/var/run/ypbind.lock"
#endif
struct _dom_binding {
struct _dom_binding *dom_pnext;
char dom_domain[YPMAXDOMAIN + 1];
struct sockaddr_in dom_server_addr;
long int dom_vers;
int dom_lockfd;
int dom_alive;
int dom_broadcast_pid;
int dom_pipe_fds[2];
int dom_default;
};
#define READFD ypdb->dom_pipe_fds[0]
#define WRITEFD ypdb->dom_pipe_fds[1]
#define BROADFD broad_domain->dom_pipe_fds[1]
extern bool_t xdr_domainname(), xdr_ypbind_resp();
extern bool_t xdr_ypreq_key(), xdr_ypresp_val();
extern bool_t xdr_ypbind_setdom();
void checkwork __P((void));
void *ypbindproc_null_2 __P((SVCXPRT *, void *, CLIENT *));
void *ypbindproc_setdom_2 __P((SVCXPRT *, struct ypbind_setdom *, CLIENT *));
void rpc_received __P((char *, struct sockaddr_in *, int ));
void broadcast __P((struct _dom_binding *));
int ping __P((struct _dom_binding *));
int tell_parent __P((char *, struct sockaddr_in *));
void handle_children __P(( struct _dom_binding * ));
void reaper __P((int));
void terminate __P((int));
void yp_restricted_mode __P((char *));
int verify __P((struct in_addr));
char *domain_name;
struct _dom_binding *ypbindlist;
static struct _dom_binding *broad_domain;
#define YPSET_NO 0
#define YPSET_LOCAL 1
#define YPSET_ALL 2
int ypsetmode = YPSET_NO;
int ypsecuremode = 0;
int ppid;
/*
* Special restricted mode variables: when in restricted mode, only the
* specified restricted_domain will be bound, and only the servers listed
* in restricted_addrs will be used for binding.
*/
#define RESTRICTED_SERVERS 10
int yp_restricted = 0;
int yp_manycast = 0;
struct in_addr restricted_addrs[RESTRICTED_SERVERS];
/* No more than MAX_CHILDREN child broadcasters at a time. */
#ifndef MAX_CHILDREN
#define MAX_CHILDREN 5
#endif
/* No more than MAX_DOMAINS simultaneous domains */
#ifndef MAX_DOMAINS
#define MAX_DOMAINS 200
#endif
/* RPC timeout value */
#ifndef FAIL_THRESHOLD
#define FAIL_THRESHOLD 20
#endif
/* Number of times to fish for a response froma particular set of hosts */
#ifndef MAX_RETRIES
#define MAX_RETRIES 30
#endif
int retries = 0;
int children = 0;
int domains = 0;
int yplockfd;
fd_set fdsr;
SVCXPRT *udptransp, *tcptransp;
void *
ypbindproc_null_2(transp, argp, clnt)
SVCXPRT *transp;
void *argp;
CLIENT *clnt;
{
static char res;
bzero((char *)&res, sizeof(res));
return (void *)&res;
}
struct ypbind_resp *
ypbindproc_domain_2(transp, argp, clnt)
SVCXPRT *transp;
domainname *argp;
CLIENT *clnt;
{
static struct ypbind_resp res;
struct _dom_binding *ypdb;
char path[MAXPATHLEN];
bzero((char *)&res, sizeof res);
res.ypbind_status = YPBIND_FAIL_VAL;
res.ypbind_resp_u.ypbind_error = YPBIND_ERR_NOSERV;
if (strchr(*argp, '/')) {
syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
rejecting.", *argp);
return(&res);
}
for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
if( strcmp(ypdb->dom_domain, *argp) == 0)
break;
}
if(ypdb==NULL) {
if (yp_restricted) {
syslog(LOG_NOTICE, "Running in restricted mode -- request to bind domain \"%s\" rejected.\n", *argp);
return &res;
}
if (domains >= MAX_DOMAINS) {
syslog(LOG_WARNING, "domain limit (%d) exceeded",
MAX_DOMAINS);
res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
return &res;
}
ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
if (ypdb == NULL) {
syslog(LOG_WARNING, "malloc: %m");
res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
return &res;
}
bzero((char *)ypdb, sizeof *ypdb);
strncpy(ypdb->dom_domain, *argp, sizeof ypdb->dom_domain);
ypdb->dom_vers = YPVERS;
ypdb->dom_alive = 0;
ypdb->dom_default = 0;
ypdb->dom_lockfd = -1;
sprintf(path, "%s/%s.%ld", BINDINGDIR,
ypdb->dom_domain, ypdb->dom_vers);
unlink(path);
ypdb->dom_pnext = ypbindlist;
ypbindlist = ypdb;
domains++;
}
if (ping(ypdb)) {
return &res;
}
res.ypbind_status = YPBIND_SUCC_VAL;
res.ypbind_resp_u.ypbind_error = 0; /* Success */
*(u_long *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr =
ypdb->dom_server_addr.sin_addr.s_addr;
*(u_short *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port =
ypdb->dom_server_addr.sin_port;
/*printf("domain %s at %s/%d\n", ypdb->dom_domain,
inet_ntoa(ypdb->dom_server_addr.sin_addr),
ntohs(ypdb->dom_server_addr.sin_port));*/
return &res;
}
void *
ypbindproc_setdom_2(transp, argp, clnt)
SVCXPRT *transp;
ypbind_setdom *argp;
CLIENT *clnt;
{
struct sockaddr_in *fromsin, bindsin;
if (strchr(argp->ypsetdom_domain, '/')) {
syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
rejecting.", argp->ypsetdom_domain);
return;
}
fromsin = svc_getcaller(transp);
switch(ypsetmode) {
case YPSET_LOCAL:
if( fromsin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
svcerr_noprog(transp);
return;
}
break;
case YPSET_ALL:
break;
case YPSET_NO:
default:
svcerr_noprog(transp);
return;
}
if(ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
svcerr_noprog(transp);
return;
}
if(argp->ypsetdom_vers != YPVERS) {
svcerr_noprog(transp);
return;
}
bzero((char *)&bindsin, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_addr.s_addr = *(u_long *)argp->ypsetdom_binding.ypbind_binding_addr;
bindsin.sin_port = *(u_short *)argp->ypsetdom_binding.ypbind_binding_port;
rpc_received(argp->ypsetdom_domain, &bindsin, 1);
return;
}
static void
ypbindprog_2(rqstp, transp)
struct svc_req *rqstp;
register SVCXPRT *transp;
{
union {
domainname ypbindproc_domain_2_arg;
struct ypbind_setdom ypbindproc_setdom_2_arg;
} argument;
struct authunix_parms *creds;
char *result;
bool_t (*xdr_argument)(), (*xdr_result)();
char *(*local)();
switch (rqstp->rq_proc) {
case YPBINDPROC_NULL:
xdr_argument = xdr_void;
xdr_result = xdr_void;
local = (char *(*)()) ypbindproc_null_2;
break;
case YPBINDPROC_DOMAIN:
xdr_argument = xdr_domainname;
xdr_result = xdr_ypbind_resp;
local = (char *(*)()) ypbindproc_domain_2;
break;
case YPBINDPROC_SETDOM:
switch(rqstp->rq_cred.oa_flavor) {
case AUTH_UNIX:
creds = (struct authunix_parms *)rqstp->rq_clntcred;
if( creds->aup_uid != 0) {
svcerr_auth(transp, AUTH_BADCRED);
return;
}
break;
default:
svcerr_auth(transp, AUTH_TOOWEAK);
return;
}
xdr_argument = xdr_ypbind_setdom;
xdr_result = xdr_void;
local = (char *(*)()) ypbindproc_setdom_2;
break;
default:
svcerr_noproc(transp);
return;
}
bzero((char *)&argument, sizeof(argument));
if (!svc_getargs(transp, xdr_argument, (caddr_t)&argument)) {
svcerr_decode(transp);
return;
}
result = (*local)(transp, &argument, rqstp);
if (result != NULL && !svc_sendreply(transp, xdr_result, result)) {
svcerr_systemerr(transp);
}
return;
}
/* Jack the reaper */
void reaper(sig)
int sig;
{
int st;
while(wait3(&st, WNOHANG, NULL) > 0)
children--;
}
void terminate(sig)
int sig;
{
struct _dom_binding *ypdb;
char path[MAXPATHLEN];
if (ppid != getpid())
exit(0);
for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
close(ypdb->dom_lockfd);
if (ypdb->dom_broadcast_pid)
kill(ypdb->dom_broadcast_pid, SIGINT);
sprintf(path, "%s/%s.%ld", BINDINGDIR,
ypdb->dom_domain, ypdb->dom_vers);
unlink(path);
}
close(yplockfd);
unlink(YPBINDLOCK);
pmap_unset(YPBINDPROG, YPBINDVERS);
exit(0);
}
int
main(argc, argv)
int argc;
char **argv;
{
char path[MAXPATHLEN];
struct timeval tv;
int i;
DIR *dird;
struct dirent *dirp;
struct _dom_binding *ypdb;
/* Check that another ypbind isn't already running. */
if ((yplockfd = (open(YPBINDLOCK, O_RDONLY|O_CREAT, 0444))) == -1) {
perror(YPBINDLOCK);
exit(1);
}
if(flock(yplockfd, LOCK_EX|LOCK_NB) == -1 && errno == EWOULDBLOCK) {
fprintf (stderr, "Another ypbind is already running. Aborting.\n");
exit(1);
}
/* XXX domainname will be overriden if we use restricted mode */
yp_get_default_domain(&domain_name);
if( domain_name[0] == '\0') {
fprintf(stderr, "domainname not set. Aborting.\n");
exit(1);
}
for(i=1; i<argc; i++) {
if( strcmp("-ypset", argv[i]) == 0)
ypsetmode = YPSET_ALL;
else if (strcmp("-ypsetme", argv[i]) == 0)
ypsetmode = YPSET_LOCAL;
else if (strcmp("-s", argv[i]) == 0)
ypsecuremode++;
else if (strcmp("-S", argv[i]) == 0 && argc > i)
yp_restricted_mode(argv[i+1]);
else if (strcmp("-m", argv[i]) == 0)
yp_manycast++;
}
/* blow away everything in BINDINGDIR (if it exists) */
if ((dird = opendir(BINDINGDIR)) != NULL) {
char path[MAXPATHLEN];
while ((dirp = readdir(dird)) != NULL)
if (strcmp(dirp->d_name, ".") &&
strcmp(dirp->d_name, "..")) {
sprintf(path,"%s/%s",BINDINGDIR,dirp->d_name);
unlink(path);
}
closedir(dird);
}
#ifdef DAEMON
if (daemon(0,0)) {
perror("fork");
exit(1);
}
#endif
pmap_unset(YPBINDPROG, YPBINDVERS);
udptransp = svcudp_create(RPC_ANYSOCK);
if (udptransp == NULL) {
fprintf(stderr, "cannot create udp service.\n");
exit(1);
}
if (!svc_register(udptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
IPPROTO_UDP)) {
fprintf(stderr, "unable to register (YPBINDPROG, YPBINDVERS, udp).\n");
exit(1);
}
tcptransp = svctcp_create(RPC_ANYSOCK, 0, 0);
if (tcptransp == NULL) {
fprintf(stderr, "cannot create tcp service.\n");
exit(1);
}
if (!svc_register(tcptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
IPPROTO_TCP)) {
fprintf(stderr, "unable to register (YPBINDPROG, YPBINDVERS, tcp).\n");
exit(1);
}
/* build initial domain binding, make it "unsuccessful" */
ypbindlist = (struct _dom_binding *)malloc(sizeof *ypbindlist);
if (ypbindlist == NULL) {
perror("malloc");
exit(1);
}
bzero((char *)ypbindlist, sizeof *ypbindlist);
strncpy(ypbindlist->dom_domain, domain_name, sizeof ypbindlist->dom_domain);
ypbindlist->dom_vers = YPVERS;
ypbindlist->dom_alive = 0;
ypbindlist->dom_lockfd = -1;
ypbindlist->dom_default = 1;
domains++;
signal(SIGCHLD, reaper);
signal(SIGTERM, terminate);
ppid = getpid(); /* Remember who we are. */
openlog(argv[0], LOG_PID, LOG_DAEMON);
/* Kick off the default domain */
broadcast(ypbindlist);
while(1) {
fdsr = svc_fdset;
tv.tv_sec = 60;
tv.tv_usec = 0;
switch(select(_rpc_dtablesize(), &fdsr, NULL, NULL, &tv)) {
case 0:
checkwork();
break;
case -1:
if (errno != EINTR)
syslog(LOG_WARNING, "select: %m");
break;
default:
for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
if (READFD > 0 && FD_ISSET(READFD, &fdsr)) {
handle_children(ypdb);
if (children == (MAX_CHILDREN - 1))
checkwork();
}
}
svc_getreqset(&fdsr);
break;
}
}
/* NOTREACHED */
exit(1);
}
void
checkwork()
{
struct _dom_binding *ypdb;
for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext)
ping(ypdb);
}
/* The clnt_broadcast() callback mechanism sucks. */
/*
* Receive results from broadcaster. Don't worry about passing
* bogus info to rpc_received() -- it can handle it. Note that we
* must be sure to invalidate the dom_pipe_fds descriptors here:
* since descriptors can be re-used, we have to make sure we
* don't mistake one of the RPC descriptors for one of the pipes.
* What's weird is that forgetting to invalidate the pipe descriptors
* doesn't always result in an error (otherwise I would have caught
* the mistake much sooner), even though logically it should.
*/
void handle_children(ypdb)
struct _dom_binding *ypdb;
{
char buf[YPMAXDOMAIN + 1];
struct sockaddr_in addr;
int d = 0, a = 0;
struct _dom_binding *y, *prev = NULL;
char path[MAXPATHLEN];
if ((d = read(READFD, &buf, sizeof(buf))) <= 0)
syslog(LOG_WARNING, "could not read from child: %m");
if ((a = read(READFD, &addr, sizeof(struct sockaddr_in))) < 0)
syslog(LOG_WARNING, "could not read from child: %m");
close(READFD);
FD_CLR(READFD, &fdsr);
FD_CLR(READFD, &svc_fdset);
READFD = WRITEFD = -1;
if (d > 0 && a > 0)
rpc_received((char *)&buf, &addr, 0);
else {
for(y=ypbindlist; y; y=y->dom_pnext) {
if (y == ypdb)
break;
prev = y;
}
switch(ypdb->dom_default) {
case 0:
if (prev == NULL)
ypbindlist = y->dom_pnext;
else
prev->dom_pnext = y->dom_pnext;
sprintf(path, "%s/%s.%ld", BINDINGDIR,
ypdb->dom_domain, YPVERS);
close(ypdb->dom_lockfd);
unlink(path);
free(ypdb);
domains--;
return;
case 1:
ypdb->dom_broadcast_pid = 0;
ypdb->dom_alive = 0;
broadcast(ypdb);
return;
default:
break;
}
}
return;
}
/*
* Send our dying words back to our parent before we perish.
*/
int
tell_parent(dom, addr)
char *dom;
struct sockaddr_in *addr;
{
char buf[YPMAXDOMAIN + 1];
struct timeval timeout;
fd_set fds;
timeout.tv_sec = 5;
timeout.tv_usec = 0;
sprintf(buf, "%s", broad_domain->dom_domain);
if (write(BROADFD, &buf, sizeof(buf)) < 0)
return(1);
/*
* Stay in sync with parent: wait for it to read our first
* message before sending the second.
*/
FD_ZERO(&fds);
FD_SET(BROADFD, &fds);
if (select(FD_SETSIZE, NULL, &fds, NULL, &timeout) == -1)
return(1);
if (FD_ISSET(BROADFD, &fds)) {
if (write(BROADFD, addr, sizeof(struct sockaddr_in)) < 0)
return(1);
} else {
return(1);
}
close(BROADFD);
return (0);
}
bool_t broadcast_result(out, addr)
bool_t *out;
struct sockaddr_in *addr;
{
if (retries >= MAX_RETRIES) {
bzero((char *)addr, sizeof(struct sockaddr_in));
if (tell_parent(broad_domain->dom_domain, addr))
syslog(LOG_WARNING, "lost connection to parent");
return TRUE;
}
if (yp_restricted && verify(addr->sin_addr)) {
retries++;
syslog(LOG_NOTICE, "NIS server at %s not in restricted mode access list -- rejecting.\n",inet_ntoa(addr->sin_addr));
return FALSE;
} else {
if (tell_parent(broad_domain->dom_domain, addr))
syslog(LOG_WARNING, "lost connection to parent");
return TRUE;
}
}
/*
* The right way to send RPC broadcasts.
* Use the clnt_broadcast() RPC service. Unfortunately, clnt_broadcast()
* blocks while waiting for replies, so we have to fork off seperate
* broadcaster processes that do the waiting and then transmit their
* results back to the parent for processing. We also have to remember
* to save the name of the domain we're trying to bind in a global
* variable since clnt_broadcast() provides no way to pass things to
* the 'eachresult' callback function.
*/
void
broadcast(ypdb)
struct _dom_binding *ypdb;
{
bool_t out = FALSE;
enum clnt_stat stat;
if (children >= MAX_CHILDREN || ypdb->dom_broadcast_pid)
return;
if (pipe(ypdb->dom_pipe_fds) < 0) {
syslog(LOG_WARNING, "pipe: %m");
return;
}
if (ypdb->dom_vers = -1 && (long)ypdb->dom_server_addr.sin_addr.s_addr)
syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" not responding",
inet_ntoa(ypdb->dom_server_addr.sin_addr), ypdb->dom_domain);
broad_domain = ypdb;
flock(ypdb->dom_lockfd, LOCK_UN);
switch((ypdb->dom_broadcast_pid = fork())) {
case 0:
close(READFD);
signal(SIGCHLD, SIG_DFL);
signal(SIGTERM, SIG_DFL);
break;
case -1:
syslog(LOG_WARNING, "fork: %m");
close(READFD);
close(WRITEFD);
return;
default:
close(WRITEFD);
FD_SET(READFD, &svc_fdset);
children++;
return;
}
/* Release all locks before doing anything else. */
while(ypbindlist) {
close(ypbindlist->dom_lockfd);
ypbindlist = ypbindlist->dom_pnext;
}
close(yplockfd);
/*
* Special 'many-cast' behavior. If we're in restricted mode,
* we have a list of possible server addresses to try. What
* we can do is transmit to each ypserv's YPPROC_DOMAIN_NONACK
* procedure and time the replies. Whoever replies fastest
* gets to be our server. Note that this is not a broadcast
* operation: we transmit uni-cast datagrams only.
*/
if (yp_restricted && yp_manycast) {
short port;
int i;
struct sockaddr_in sin;
i = __yp_ping(restricted_addrs, yp_restricted,
ypdb->dom_domain, &port);
if (i == -1) {
bzero((char *)&ypdb->dom_server_addr,
sizeof(struct sockaddr_in));
if (tell_parent(ypdb->dom_domain,
&ypdb->dom_server_addr))
syslog(LOG_WARNING, "lost connection to parent");
} else {
bzero((char *)&sin, sizeof(struct sockaddr_in));
bcopy((char *)&restricted_addrs[i],
(char *)&sin.sin_addr, sizeof(struct in_addr));
sin.sin_family = AF_INET;
sin.sin_port = port;
if (tell_parent(broad_domain->dom_domain, &sin))
syslog(LOG_WARNING,
"lost connection to parent");
}
_exit(0);
}
retries = 0;
{
char *ptr;
ptr = (char *)&ypdb->dom_domain;
stat = clnt_broadcast(YPPROG, YPVERS, YPPROC_DOMAIN_NONACK,
xdr_domainname, (char *)&ptr, xdr_bool, (char *)&out,
broadcast_result);
}
if (stat != RPC_SUCCESS) {
bzero((char *)&ypdb->dom_server_addr,
sizeof(struct sockaddr_in));
if (tell_parent(ypdb->dom_domain, &ypdb->dom_server_addr))
syslog(LOG_WARNING, "lost connection to parent");
}
_exit(0);
}
/*
* The right way to check if a server is alive.
* Attempt to get a client handle pointing to the server and send a
* YPPROC_DOMAIN. If we can't get a handle or we get a reply of FALSE,
* we invalidate this binding entry and send out a broadcast to try to
* establish a new binding. Note that we treat non-default domains
* specially: once bound, we keep tabs on our server, but if it
* goes away and fails to respond after one round of broadcasting, we
* abandon it until a client specifically references it again. We make
* every effort to keep our default domain bound, however, since we
* need it to keep the system on its feet.
*/
int
ping(ypdb)
struct _dom_binding *ypdb;
{
bool_t out;
struct timeval interval, timeout;
enum clnt_stat stat;
int rpcsock = RPC_ANYSOCK;
CLIENT *client_handle;
time_t t;
interval.tv_sec = FAIL_THRESHOLD;
interval.tv_usec = 0;
timeout.tv_sec = FAIL_THRESHOLD;
timeout.tv_usec = 0;
if (ypdb->dom_broadcast_pid)
return(1);
if ((client_handle = clntudp_bufcreate(&ypdb->dom_server_addr,
YPPROG, YPVERS, interval, &rpcsock, RPCSMALLMSGSIZE,
RPCSMALLMSGSIZE)) == (CLIENT *)NULL) {
/* Can't get a handle: we're dead. */
ypdb->dom_alive = 0;
ypdb->dom_vers = -1;
broadcast(ypdb);
return(1);
}
{
char *ptr;
ptr = (char *)&ypdb->dom_domain;
if ((stat = clnt_call(client_handle, YPPROC_DOMAIN,
xdr_domainname, (char *)&ptr, xdr_bool, (char *)&out,
timeout)) != RPC_SUCCESS || out == FALSE) {
ypdb->dom_alive = 0;
ypdb->dom_vers = -1;
clnt_destroy(client_handle);
broadcast(ypdb);
return(1);
}
}
clnt_destroy(client_handle);
return(0);
}
void rpc_received(dom, raddrp, force)
char *dom;
struct sockaddr_in *raddrp;
int force;
{
struct _dom_binding *ypdb, *prev = NULL;
struct iovec iov[2];
struct ypbind_resp ybr;
char path[MAXPATHLEN];
int fd;
/*printf("returned from %s/%d about %s\n", inet_ntoa(raddrp->sin_addr),
ntohs(raddrp->sin_port), dom);*/
if(dom==NULL)
return;
for(ypdb=ypbindlist; ypdb; ypdb=ypdb->dom_pnext) {
if( strcmp(ypdb->dom_domain, dom) == 0)
break;
prev = ypdb;
}
if (ypdb && force) {
if (ypdb->dom_broadcast_pid) {
kill(ypdb->dom_broadcast_pid, SIGINT);
close(READFD);
FD_CLR(READFD, &fdsr);
FD_CLR(READFD, &svc_fdset);
READFD = WRITEFD = -1;
}
}
/* if in secure mode, check originating port number */
if ((ypsecuremode && (ntohs(raddrp->sin_port) >= IPPORT_RESERVED))) {
syslog(LOG_WARNING, "Rejected NIS server on [%s/%d] for domain %s.",
inet_ntoa(raddrp->sin_addr), ntohs(raddrp->sin_port),
dom);
if (ypdb != NULL) {
ypdb->dom_broadcast_pid = 0;
ypdb->dom_alive = 0;
}
return;
}
if (raddrp->sin_addr.s_addr == (long)0) {
switch(ypdb->dom_default) {
case 0:
if (prev == NULL)
ypbindlist = ypdb->dom_pnext;
else
prev->dom_pnext = ypdb->dom_pnext;
sprintf(path, "%s/%s.%ld", BINDINGDIR,
ypdb->dom_domain, YPVERS);
close(ypdb->dom_lockfd);
unlink(path);
free(ypdb);
domains--;
return;
case 1:
ypdb->dom_broadcast_pid = 0;
ypdb->dom_alive = 0;
broadcast(ypdb);
return;
default:
break;
}
}
if(ypdb==NULL) {
if (force == 0)
return;
ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
if (ypdb == NULL) {
syslog(LOG_WARNING, "malloc: %m");
return;
}
bzero((char *)ypdb, sizeof *ypdb);
strncpy(ypdb->dom_domain, dom, sizeof ypdb->dom_domain);
ypdb->dom_lockfd = -1;
ypdb->dom_default = 0;
ypdb->dom_pnext = ypbindlist;
ypbindlist = ypdb;
}
/* We've recovered from a crash: inform the world. */
if (ypdb->dom_vers = -1 && ypdb->dom_server_addr.sin_addr.s_addr)
syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" OK",
inet_ntoa(raddrp->sin_addr), ypdb->dom_domain);
bcopy((char *)raddrp, (char *)&ypdb->dom_server_addr,
sizeof ypdb->dom_server_addr);
ypdb->dom_vers = YPVERS;
ypdb->dom_alive = 1;
ypdb->dom_broadcast_pid = 0;
if(ypdb->dom_lockfd != -1)
close(ypdb->dom_lockfd);
sprintf(path, "%s/%s.%ld", BINDINGDIR,
ypdb->dom_domain, ypdb->dom_vers);
#ifdef O_SHLOCK
if( (fd=open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1) {
(void)mkdir(BINDINGDIR, 0755);
if( (fd=open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1)
return;
}
#else
if( (fd=open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1) {
(void)mkdir(BINDINGDIR, 0755);
if( (fd=open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1)
return;
}
flock(fd, LOCK_SH);
#endif
/*
* ok, if BINDINGDIR exists, and we can create the binding file,
* then write to it..
*/
ypdb->dom_lockfd = fd;
iov[0].iov_base = (caddr_t)&(udptransp->xp_port);
iov[0].iov_len = sizeof udptransp->xp_port;
iov[1].iov_base = (caddr_t)&ybr;
iov[1].iov_len = sizeof ybr;
bzero(&ybr, sizeof ybr);
ybr.ypbind_status = YPBIND_SUCC_VAL;
*(u_long *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr = raddrp->sin_addr.s_addr;
*(u_short *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port = raddrp->sin_port;
if( writev(ypdb->dom_lockfd, iov, 2) != iov[0].iov_len + iov[1].iov_len) {
syslog(LOG_WARNING, "write: %m");
close(ypdb->dom_lockfd);
ypdb->dom_lockfd = -1;
return;
}
}
/*
* Check address against list of allowed servers. Return 0 if okay,
* 1 if not matched.
*/
int
verify(addr)
struct in_addr addr;
{
int i;
for (i = 0; i < RESTRICTED_SERVERS; i++)
if (!bcmp((char *)&addr, (char *)&restricted_addrs[i],
sizeof(struct in_addr)))
return(0);
return(1);
}
/*
* Try to set restricted mode. We default to normal mode if we can't
* resolve the specified hostnames.
*/
void
yp_restricted_mode(args)
char *args;
{
struct hostent *h;
int i = 0;
char *s;
/* Find the restricted domain. */
if ((s = strsep(&args, ",")) == NULL)
return;
domain_name = s;
/* Get the addresses of the servers. */
while ((s = strsep(&args, ",")) != NULL && i < RESTRICTED_SERVERS) {
if ((h = gethostbyname(s)) == NULL)
return;
bcopy ((char *)h->h_addr_list[0], (char *)&restricted_addrs[i],
sizeof(struct in_addr));
i++;
}
/* ypset and ypsetme not allowed with restricted mode */
ypsetmode = YPSET_NO;
yp_restricted = i;
return;
}