/*
* __rpc_get_time_offset()
*
* This function uses a nis_server structure to contact the a remote
* machine (as named in that structure) and returns the offset in time
* between that machine and this one. This offset is returned in seconds
* and may be positive or negative.
*
* The first time through, a lot of fiddling is done with the netconfig
* stuff to find a suitable transport. The function is very aggressive
* about choosing UDP or at worst TCP if it can. This is because
* those transports support both the RCPBIND call and the internet
* time service.
*
* Once through, *uaddr is set to the universal address of
* the machine and *netid is set to the local netid for the transport
* that uaddr goes with. On the second call, the netconfig stuff
* is skipped and the uaddr/netid pair are used to fetch the netconfig
* structure and to then contact the machine for the time.
*
* td = "server" - "client"
*/
int
__rpc_get_time_offset(struct timeval *td, /* Time difference */
nis_server *srv, /* NIS Server description */
char *thost, /* if no server, this is the timehost */
char **uaddr, /* known universal address */
struct sockaddr_in *netid /* known network identifier */)
{
CLIENT *clnt; /* Client handle */
AUTH *auth;
endpoint *ep, /* useful endpoints */
*useep = NULL; /* endpoint of xp */
char *useua = NULL; /* uaddr of selected xp */
int epl, i; /* counters */
enum clnt_stat status; /* result of clnt_call */
u_long thetime, delta;
int needfree = 0;
struct timeval tv;
struct timespec ts;
int time_valid;
int udp_ep = -1, tcp_ep = -1;
int a1, a2, a3, a4;
char ut[64], ipuaddr[64];
endpoint teps[32];
nis_server tsrv;
void (*oldsig)() = NULL; /* old alarm handler */
struct sockaddr_in sin;
int s = RPC_ANYSOCK;
socklen_t len;
int type = 0;
div_t q;
td->tv_sec = 0;
td->tv_usec = 0;
/*
* First check to see if we need to find and address for this
* server.
*/
if (*uaddr == NULL) {
if ((srv != NULL) && (thost != NULL)) {
msg("both timehost and srv pointer used!");
return (0);
}
if (! srv) {
srv = get_server(netid, thost, &tsrv, teps, 32);
if (srv == NULL) {
msg("unable to contruct server data.");
return (0);
}
needfree = 1; /* need to free data in endpoints */
}
ep = srv->ep.ep_val;
epl = srv->ep.ep_len;
/* Identify the TCP and UDP endpoints */
for (i = 0;
(i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
if (strcasecmp(ep[i].proto, "udp") == 0)
udp_ep = i;
if (strcasecmp(ep[i].proto, "tcp") == 0)
tcp_ep = i;
}
/* Check to see if it is UDP or TCP */
if (tcp_ep > -1) {
useep = &ep[tcp_ep];
useua = ep[tcp_ep].uaddr;
type = SOCK_STREAM;
} else if (udp_ep > -1) {
useep = &ep[udp_ep];
useua = ep[udp_ep].uaddr;
type = SOCK_DGRAM;
}
if (useep == NULL) {
msg("no acceptable transport endpoints.");
if (needfree)
free_eps(teps, tsrv.ep.ep_len);
return (0);
}
}
/*
* Create a sockaddr from the uaddr.
*/
if (*uaddr != NULL)
useua = *uaddr;
/* Fixup test for NIS+ */
sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
useua = &ipuaddr[0];
bzero((char *)&sin, sizeof(sin));
if (uaddr_to_sockaddr(useua, &sin)) {
msg("unable to translate uaddr to sockaddr.");
if (needfree)
free_eps(teps, tsrv.ep.ep_len);
return (0);
}
/*
* Create the client handle to rpcbind. Note we always try
* version 3 since that is the earliest version that supports
* the RPCB_GETTIME call. Also it is the version that comes
* standard with SVR4. Since most everyone supports TCP/IP
* we could consider trying the rtime call first.
*/
clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
if (clnt == NULL) {
msg("unable to create client handle to rpcbind.");
if (needfree)
free_eps(teps, tsrv.ep.ep_len);
return (0);
}
auth = authnone_ncreate(); /* idempotent */
tv.tv_sec = 5;
tv.tv_usec = 0;
time_valid = 0;
status = clnt_call(clnt, auth, RPCBPROC_GETTIME, (xdrproc_t)xdr_void, NULL,
(xdrproc_t)xdr_u_long, &thetime, tv);
/*
* The only error we check for is anything but success. In
* fact we could have seen PROGMISMATCH if talking to a 4.1
* machine (pmap v2) or TIMEDOUT if the net was busy.
*/
if (status == RPC_SUCCESS)
time_valid = 1;
else {
int save;
/* Blow away possible stale CLNT handle. */
if (clnt != NULL) {
clnt_destroy(clnt);
clnt = NULL;
}
/*
* Convert PMAP address into timeservice address
* We take advantage of the fact that we "know" what
* the universal address looks like for inet transports.
*
* We also know that the internet timeservice is always
* listening on port 37.
*/
sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);
if (uaddr_to_sockaddr(ut, &sin)) {
msg("cannot convert timeservice uaddr to sockaddr.");
goto error;
}
s = socket(AF_INET, type, 0);
if (s == -1) {
msg("unable to open fd to network.");
goto error;
}
/*
* Now depending on whether or not we're talking to
* UDP we set a timeout or not.
*/
if (type == SOCK_DGRAM) {
struct timeval timeout = { 20, 0 };
struct sockaddr_in from;
fd_set readfds;
int res;
if (sendto(s, &thetime, sizeof(thetime), 0,
(struct sockaddr *)&sin, sizeof(sin)) == -1) {
msg("udp : sendto failed.");
goto error;
}
do {
FD_ZERO(&readfds);
FD_SET(s, &readfds);
res = select(_rpc_dtablesize(), &readfds,
(fd_set *)NULL, (fd_set *)NULL, &timeout);
} while (res < 0 && errno == EINTR);
if (res <= 0)
goto error;
len = sizeof(from);
res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
(struct sockaddr *)&from, &len);
if (res == -1) {
msg("recvfrom failed on udp transport.");
goto error;
}
time_valid = 1;
} else {
int res;
oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
saw_alarm = 0; /* global tracking the alarm */
alarm(20); /* only wait 20 seconds */
res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
if (res == -1) {
msg("failed to connect to tcp endpoint.");
goto error;
}
if (saw_alarm) {
msg("alarm caught it, must be unreachable.");
goto error;
}
res = read(s, (char *)&thetime, sizeof(thetime));
if (res != sizeof(thetime)) {
if (saw_alarm)
msg("timed out TCP call.");
else
msg("wrong size of results returned");
goto error;
}
time_valid = 1;
}
save = errno;
(void)close(s);
errno = save;
s = RPC_ANYSOCK;
if (time_valid) {
thetime = ntohl(thetime);
thetime = thetime - TOFFSET; /* adjust to UNIX time */
} else
thetime = 0;
}
(void) clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
tv.tv_sec = ts.tv_sec;
q = div(ts.tv_nsec, 1000);
tv.tv_usec = q.quot;
error:
/*
* clean up our allocated data structures.
*/
if (s != RPC_ANYSOCK)
(void)close(s);
if (clnt != NULL)
clnt_destroy(clnt);
alarm(0); /* reset that alarm if its outstanding */
if (oldsig) {
signal(SIGALRM, oldsig);
}
/*
* note, don't free uaddr strings until after we've made a
* copy of them.
*/
if (time_valid) {
if (*uaddr == NULL)
*uaddr = rpc_strdup(useua);
/* Round to the nearest second */
tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
tv.tv_sec - thetime;
td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
td->tv_usec = 0;
} else {
msg("unable to get the server's time.");
}
if (needfree)
free_eps(teps, tsrv.ep.ep_len);
return (time_valid);
}
/*
* get_server()
*
* This function constructs a nis_server structure description for the
* indicated hostname.
*
* NOTE: There is a chance we may end up recursing here due to the
* fact that gethostbyname() could do an NIS search. Ideally, the
* NIS+ server will call __rpc_get_time_offset() with the nis_server
* structure already populated.
*/
static nis_server *
get_server(struct sockaddr_in *sin,
char *host, /* name of the time host */
nis_server *srv, /* nis_server struct to use. */
endpoint eps[], /* array of endpoints */
int maxep) /* max array size */
{
char hname[256];
int num_ep = 0, i;
struct hostent *he;
struct hostent dummy;
char *ptr[2];
endpoint *ep;
if (host == NULL && sin == NULL)
return (NULL);
if (sin == NULL) {
he = gethostbyname(host);
if (he == NULL)
return(NULL);
} else {
he = &dummy;
ptr[0] = (char *)&sin->sin_addr.s_addr;
ptr[1] = NULL;
dummy.h_addr_list = ptr;
}
/*
* This is lame. We go around once for TCP, then again
* for UDP.
*/
for (i = 0, ep = eps; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
i++, ep++, num_ep++) {
struct in_addr *a;
a = (struct in_addr *)he->h_addr_list[i];
snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
ep->uaddr = strdup(hname);
ep->family = strdup("inet");
ep->proto = strdup("tcp");
if (ep->uaddr == NULL || ep->family == NULL || ep->proto == NULL) {
free_eps(eps, num_ep + 1);
return (NULL);
}
}
for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
i++, ep++, num_ep++) {
struct in_addr *a;
a = (struct in_addr *)he->h_addr_list[i];
snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
ep->uaddr = strdup(hname);
ep->family = strdup("inet");
ep->proto = strdup("udp");
if (ep->uaddr == NULL || ep->family == NULL || ep->proto == NULL) {
free_eps(eps, num_ep + 1);
return (NULL);
}
}
srv->name = (nis_name) host;
srv->ep.ep_len = num_ep;
srv->ep.ep_val = eps;
srv->key_type = NIS_PK_NONE;
srv->pkey.n_bytes = NULL;
srv->pkey.n_len = 0;
return (srv);
}
