/* XXX handle responses with the error bit set */
double jitter_request(const char *host, int *status){
int conn=-1, i, npeers=0, num_candidates=0, syncsource_found=0;
int run=0, min_peer_sel=PEER_INCLUDED, num_selected=0, num_valid=0;
int peers_size=0, peer_offset=0, bytes_read=0;
ntp_assoc_status_pair *peers=NULL;
ntp_control_message req;
const char *getvar = "jitter";
double rval = 0.0, jitter = -1.0;
char *startofvalue=NULL, *nptr=NULL;
void *tmp;
int ntp_cm_ints = sizeof(uint16_t) * 5 + sizeof(uint8_t) * 2;
/* Long-winded explanation:
* Getting the jitter requires a number of steps:
* 1) Send a READSTAT request.
* 2) Interpret the READSTAT reply
* a) The data section contains a list of peer identifiers (16 bits)
* and associated status words (16 bits)
* b) We want the value of 0x06 in the SEL (peer selection) value,
* which means "current synchronizatin source". If that's missing,
* we take anything better than 0x04 (see the rfc for details) but
* set a minimum of warning.
* 3) Send a READVAR request for information on each peer identified
* in 2b greater than the minimum selection value.
* 4) Extract the jitter value from the data[] (it's ASCII)
*/
my_udp_connect(server_address, 123, &conn);
/* keep sending requests until the server stops setting the
* REM_MORE bit, though usually this is only 1 packet. */
do{
setup_control_request(&req, OP_READSTAT, 1);
DBG(printf("sending READSTAT request"));
write(conn, &req, SIZEOF_NTPCM(req));
DBG(print_ntp_control_message(&req));
/* Attempt to read the largest size packet possible */
req.count=htons(MAX_CM_SIZE);
DBG(printf("recieving READSTAT response"))
read(conn, &req, SIZEOF_NTPCM(req));
DBG(print_ntp_control_message(&req));
/* Each peer identifier is 4 bytes in the data section, which
* we represent as a ntp_assoc_status_pair datatype.
*/
peers_size+=ntohs(req.count);
if((tmp=realloc(peers, peers_size)) == NULL)
free(peers), die(STATE_UNKNOWN, "can not (re)allocate 'peers' buffer\n");
peers=tmp;
memcpy((void*)((ptrdiff_t)peers+peer_offset), (void*)req.data, ntohs(req.count));
npeers=peers_size/sizeof(ntp_assoc_status_pair);
peer_offset+=ntohs(req.count);
} while(req.op&REM_MORE);
/* first, let's find out if we have a sync source, or if there are
* at least some candidates. in the case of the latter we'll issue
* a warning but go ahead with the check on them. */
for (i = 0; i < npeers; i++){
if (PEER_SEL(peers[i].status) >= PEER_INCLUDED){
num_candidates++;
if(PEER_SEL(peers[i].status) >= PEER_SYNCSOURCE){
syncsource_found=1;
min_peer_sel=PEER_SYNCSOURCE;
}
}
}
if(verbose) printf("%d candiate peers available\n", num_candidates);
if(verbose && syncsource_found) printf("synchronization source found\n");
if(! syncsource_found){
*status = STATE_UNKNOWN;
if(verbose) printf("warning: no synchronization source found\n");
}
for (run=0; run<AVG_NUM; run++){
if(verbose) printf("jitter run %d of %d\n", run+1, AVG_NUM);
for (i = 0; i < npeers; i++){
/* Only query this server if it is the current sync source */
if (PEER_SEL(peers[i].status) >= min_peer_sel){
num_selected++;
setup_control_request(&req, OP_READVAR, 2);
req.assoc = peers[i].assoc;
/* By spec, putting the variable name "jitter" in the request
* should cause the server to provide _only_ the jitter value.
* thus reducing net traffic, guaranteeing us only a single
* datagram in reply, and making intepretation much simpler
*/
/* Older servers doesn't know what jitter is, so if we get an
* error on the first pass we redo it with "dispersion" */
strncpy(req.data, getvar, MAX_CM_SIZE-1);
req.count = htons(strlen(getvar));
DBG(printf("sending READVAR request...\n"));
write(conn, &req, SIZEOF_NTPCM(req));
DBG(print_ntp_control_message(&req));
req.count = htons(MAX_CM_SIZE);
DBG(printf("recieving READVAR response...\n"));
/* cov-66524 - req.data not null terminated before usage. Also covers verifying struct was returned correctly*/
if ((bytes_read = read(conn, &req, SIZEOF_NTPCM(req))) == -1)
die(STATE_UNKNOWN, _("Cannot read from socket: %s"), strerror(errno));
if (bytes_read != ntp_cm_ints + req.count)
die(STATE_UNKNOWN, _("Invalid NTP response: %d bytes read does not equal %d plus %d data segment"), bytes_read, ntp_cm_ints, req.count);
/* else null terminate */
strncpy(req.data[req.count], "\0", 1);
DBG(print_ntp_control_message(&req));
if(req.op&REM_ERROR && strstr(getvar, "jitter")) {
if(verbose) printf("The 'jitter' command failed (old ntp server?)\nRestarting with 'dispersion'...\n");
getvar = "dispersion";
num_selected--;
i--;
continue;
}
/* get to the float value */
if(verbose) {
printf("parsing jitter from peer %.2x: ", ntohs(peers[i].assoc));
}
startofvalue = strchr(req.data, '=');
if(startofvalue != NULL) {
startofvalue++;
jitter = strtod(startofvalue, &nptr);
}
if(startofvalue == NULL || startofvalue==nptr){
printf("warning: unable to read server jitter response.\n");
*status = STATE_UNKNOWN;
} else {
if(verbose) printf("%g\n", jitter);
num_valid++;
rval += jitter;
}
}
}
if(verbose){
printf("jitter parsed from %d/%d peers\n", num_valid, num_selected);
}
}
rval = num_valid ? rval / num_valid : -1.0;
close(conn);
if(peers!=NULL) free(peers);
/* If we return -1.0, it means no synchronization source was found */
return rval;
}
int
main (int argc, char **argv)
{
int sd;
int result = STATE_UNKNOWN;
time_t conntime;
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/* Parse extra opts if any */
argv=np_extra_opts (&argc, argv, progname);
if (process_arguments (argc, argv) == ERROR)
usage4 (_("Could not parse arguments"));
/* initialize alarm signal handling */
signal (SIGALRM, socket_timeout_alarm_handler);
/* set socket timeout */
alarm (socket_timeout);
time (&start_time);
/* try to connect to the host at the given port number */
if (use_udp) {
result = my_udp_connect (server_address, server_port, &sd);
} else {
result = my_tcp_connect (server_address, server_port, &sd);
}
if (result != STATE_OK) {
if (check_critical_time == TRUE)
result = STATE_CRITICAL;
else if (check_warning_time == TRUE)
result = STATE_WARNING;
else
result = STATE_UNKNOWN;
die (result,
_("TIME UNKNOWN - could not connect to server %s, port %d\n"),
server_address, server_port);
}
if (use_udp) {
if (send (sd, "", 0, 0) < 0) {
if (check_critical_time == TRUE)
result = STATE_CRITICAL;
else if (check_warning_time == TRUE)
result = STATE_WARNING;
else
result = STATE_UNKNOWN;
die (result,
_("TIME UNKNOWN - could not send UDP request to server %s, port %d\n"),
server_address, server_port);
}
}
/* watch for the connection string */
result = recv (sd, (void *)&raw_server_time, sizeof (raw_server_time), 0);
/* close the connection */
close (sd);
/* reset the alarm */
time (&end_time);
alarm (0);
/* return a WARNING status if we couldn't read any data */
if (result <= 0) {
if (check_critical_time == TRUE)
result = STATE_CRITICAL;
else if (check_warning_time == TRUE)
result = STATE_WARNING;
else
result = STATE_UNKNOWN;
die (result,
_("TIME UNKNOWN - no data received from server %s, port %d\n"),
server_address, server_port);
}
result = STATE_OK;
conntime = (end_time - start_time);
if (check_critical_time == TRUE && conntime > critical_time)
result = STATE_CRITICAL;
else if (check_warning_time == TRUE && conntime > warning_time)
result = STATE_WARNING;
if (result != STATE_OK)
die (result, _("TIME %s - %d second response time|%s\n"),
state_text (result), (int)conntime,
perfdata ("time", (long)conntime, "s",
check_warning_time, (long)warning_time,
check_critical_time, (long)critical_time,
TRUE, 0, FALSE, 0));
server_time = ntohl (raw_server_time) - UNIX_EPOCH;
if (server_time > (unsigned long)end_time)
diff_time = server_time - (unsigned long)end_time;
else
diff_time = (unsigned long)end_time - server_time;
if (check_critical_diff == TRUE && diff_time > critical_diff)
result = STATE_CRITICAL;
else if (check_warning_diff == TRUE && diff_time > warning_diff)
result = STATE_WARNING;
printf (_("TIME %s - %lu second time difference|%s %s\n"),
state_text (result), diff_time,
perfdata ("time", (long)conntime, "s",
check_warning_time, (long)warning_time,
check_critical_time, (long)critical_time,
TRUE, 0, FALSE, 0),
perfdata ("offset", diff_time, "s",
check_warning_diff, warning_diff,
check_critical_diff, critical_diff,
TRUE, 0, FALSE, 0));
return result;
}
