diff options
Diffstat (limited to 'plugins/check_ntp_time.c')
-rw-r--r-- | plugins/check_ntp_time.c | 68 |
1 files changed, 35 insertions, 33 deletions
diff --git a/plugins/check_ntp_time.c b/plugins/check_ntp_time.c index 16e4c3c7..11a0eced 100644 --- a/plugins/check_ntp_time.c +++ b/plugins/check_ntp_time.c | |||
@@ -247,50 +247,52 @@ void setup_request(ntp_message *p){ | |||
247 | * this is done by filtering servers based on stratum, dispersion, and | 247 | * this is done by filtering servers based on stratum, dispersion, and |
248 | * finally round-trip delay. */ | 248 | * finally round-trip delay. */ |
249 | int best_offset_server(const ntp_server_results *slist, int nservers){ | 249 | int best_offset_server(const ntp_server_results *slist, int nservers){ |
250 | int i=0, j=0, cserver=0, candidates[5], csize=0; | 250 | int i=0, cserver=0, best_server=-1; |
251 | 251 | ||
252 | /* for each server */ | 252 | /* for each server */ |
253 | for(cserver=0; cserver<nservers; cserver++){ | 253 | for(cserver=0; cserver<nservers; cserver++){ |
254 | /* sort out servers with error flags */ | 254 | /* We don't want any servers that fails these tests */ |
255 | if ( LI(slist[cserver].flags) != LI_NOWARNING ){ | 255 | /* Sort out servers that didn't respond or responede with a 0 stratum; |
256 | if (verbose) printf("discarding peer id %d: flags=%d\n", cserver, LI(slist[cserver].flags)); | 256 | * stratum 0 is for reference clocks so no NTP server should ever report |
257 | break; | 257 | * a stratum 0 */ |
258 | if ( slist[cserver].stratum == 0){ | ||
259 | if (verbose) printf("discarding peer %d: stratum=%d\n", cserver, slist[cserver].stratum); | ||
260 | continue; | ||
261 | } | ||
262 | /* Sort out servers with error flags */ | ||
263 | if ( LI(slist[cserver].flags) == LI_ALARM ){ | ||
264 | if (verbose) printf("discarding peer %d: flags=%d\n", cserver, LI(slist[cserver].flags)); | ||
265 | continue; | ||
258 | } | 266 | } |
259 | 267 | ||
260 | /* compare it to each of the servers already in the candidate list */ | 268 | /* If we don't have a server yet, use the first one */ |
261 | for(i=0; i<csize; i++){ | 269 | if (best_server == -1) { |
262 | /* does it have an equal or better stratum? */ | 270 | best_server = cserver; |
263 | if(slist[cserver].stratum <= slist[i].stratum){ | 271 | DBG(printf("using peer %d as our first candidate\n", best_server)); |
264 | /* does it have an equal or better dispersion? */ | 272 | continue; |
265 | if(slist[cserver].rtdisp <= slist[i].rtdisp){ | ||
266 | /* does it have a better rtdelay? */ | ||
267 | if(slist[cserver].rtdelay < slist[i].rtdelay){ | ||
268 | break; | ||
269 | } | ||
270 | } | ||
271 | } | ||
272 | } | 273 | } |
273 | 274 | ||
274 | /* if we haven't reached the current list's end, move everyone | 275 | /* compare the server to the best one we've seen so far */ |
275 | * over one to the right, and insert the new candidate */ | 276 | /* does it have an equal or better stratum? */ |
276 | if(i<csize){ | 277 | DBG(printf("comparing peer %d with peer %d\n", cserver, best_server)); |
277 | for(j=4; j>i; j--){ | 278 | if(slist[cserver].stratum <= slist[best_server].stratum){ |
278 | candidates[j]=candidates[j-1]; | 279 | DBG(printf("stratum for peer %d <= peer %d\n", cserver, best_server)); |
280 | /* does it have an equal or better dispersion? */ | ||
281 | if(slist[cserver].rtdisp <= slist[best_server].rtdisp){ | ||
282 | DBG(printf("dispersion for peer %d <= peer %d\n", cserver, best_server)); | ||
283 | /* does it have a better rtdelay? */ | ||
284 | if(slist[cserver].rtdelay < slist[best_server].rtdelay){ | ||
285 | DBG(printf("rtdelay for peer %d < peer %d\n", cserver, best_server)); | ||
286 | best_server = cserver; | ||
287 | DBG(printf("peer %d is now our best candidate\n", best_server)); | ||
288 | } | ||
279 | } | 289 | } |
280 | } | 290 | } |
281 | /* regardless, if they should be on the list... */ | ||
282 | if(i<5) { | ||
283 | candidates[i]=cserver; | ||
284 | if(csize<5) csize++; | ||
285 | /* otherwise discard the server */ | ||
286 | } else { | ||
287 | DBG(printf("discarding peer id %d\n", cserver)); | ||
288 | } | ||
289 | } | 291 | } |
290 | 292 | ||
291 | if(csize>0) { | 293 | if(best_server >= 0) { |
292 | DBG(printf("best server selected: peer %d\n", candidates[0])); | 294 | DBG(printf("best server selected: peer %d\n", best_server)); |
293 | return candidates[0]; | 295 | return best_server; |
294 | } else { | 296 | } else { |
295 | DBG(printf("no peers meeting synchronization criteria :(\n")); | 297 | DBG(printf("no peers meeting synchronization criteria :(\n")); |
296 | return -1; | 298 | return -1; |