1 files changed, 82 insertions, 48 deletions

diff --git a/plugins/check_ntp_peer.c b/plugins/check_ntp_peer.c
index 016a034e..5d21832b 100644
--- a/plugins/check_ntp_peer.c
+++ b/plugins/check_ntp_peer.c
@@ -180,6 +180,10 @@ char *extract_value(const char *varlist, const char *name){
         char *tmpvarlist=NULL, *tmpkey=NULL, *value=NULL;
         int last=0;
 
+  /* The following code require a non-empty varlist */
+        if(strlen(varlist) == 0)
+                return NULL;
+
         tmpvarlist = strdup(varlist);
         tmpkey = strtok(tmpvarlist, "=");
 
@@ -204,21 +208,32 @@ setup_control_request(ntp_control_message *p, uint8_t opcode, uint16_t seq){
         /* Remaining fields are zero for requests */
 }
 
-/* XXX handle responses with the error bit set */
+/* This function does all the actual work; roughly here's what it does
+ * beside setting the offest, jitter and stratum passed as argument:
+ *  - offset can be negative, so if it cannot get the offset, offset_result
+ *    is set to UNKNOWN, otherwise OK.
+ *  - jitter and stratum are set to -1 if they cannot be retrieved so any
+ *    positive value means a success retrieving the value.
+ *  - status is set to WARNING if there's no sync.peer (otherwise OK) and is
+ *    the return value of the function.
+ *  status is pretty much useless as syncsource_found is a global variable
+ *  used later in main to check is the server was synchronized. It works
+ *  so I left it alone, but it can be repurposed if needed */
 int ntp_request(const char *host, double *offset, int *offset_result, double *jitter, int *stratum){
         int conn=-1, i, npeers=0, num_candidates=0;
+        double tmp_offset = 0;
         int min_peer_sel=PEER_INCLUDED;
         int peers_size=0, peer_offset=0;
         int status;
         ntp_assoc_status_pair *peers=NULL;
         ntp_control_message req;
         const char *getvar = "stratum,offset,jitter";
+        char *data="";
         char *value=NULL, *nptr=NULL;
         void *tmp;
 
         status = STATE_OK;
         *offset_result = STATE_UNKNOWN;
-        *jitter = *stratum = -1;
 
         /* Long-winded explanation:
          * Getting the sync peer offset, jitter and stratum requires a number of
@@ -284,87 +299,104 @@ int ntp_request(const char *host, double *offset, int *offset_result, double *ji
 
         for (i = 0; i < npeers; i++){
                 /* Only query this server if it is the current sync source */
+                /* If there's no sync.peer, query all candidates and use the best one */
                 if (PEER_SEL(peers[i].status) >= min_peer_sel){
             if(verbose) printf("Getting offset, jitter and stratum for peer %.2x\n", ntohs(peers[i].assoc));
-                        setup_control_request(&req, OP_READVAR, 2);
-                        req.assoc = peers[i].assoc;
-                        /* Putting the wanted variable names in the request
-                         * cause the server to provide _only_ the requested values.
-                         * 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"));
-                        read(conn, &req, SIZEOF_NTPCM(req));
-                        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 = "stratum,offset,dispersion";
-                                i--;
-                                continue;
+                        data = "\0";
+                        do{
+                                setup_control_request(&req, OP_READVAR, 2);
+                                req.assoc = peers[i].assoc;
+                                /* Putting the wanted variable names in the request
+                                 * cause the server to provide _only_ the requested values.
+                                 * 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("receiving READVAR response...\n"));
+                                read(conn, &req, SIZEOF_NTPCM(req));
+                                DBG(print_ntp_control_message(&req));
+
+                                if(!(req.op&REM_ERROR))
+                                        asprintf(&data, "%s%s", data, req.data);
+                        } while(req.op&REM_MORE);
+
+                        if(req.op&REM_ERROR) {
+                                if(strstr(getvar, "jitter")) {
+                                        if(verbose) printf("The command failed. This is usually caused by servers refusing the 'jitter'\nvariable. Restarting with 'dispersion'...\n");
+                                        getvar = "stratum,offset,dispersion";
+                                        i--;
+                                        continue;
+                                } else if(strlen(getvar))  {
+                                        if(verbose) printf("Server didn't like dispersion either; will retrieve everything\n");
+                                        getvar = "";
+                                        i--;
+                                        continue;
+                                }
                         }
 
                         if(verbose > 1)
-                                printf("Server responded: >>>%s<<<\n", req.data);
+                                printf("Server responded: >>>%s<<<\n", data);
 
                         /* get the offset */
                         if(verbose)
                                 printf("parsing offset from peer %.2x: ", ntohs(peers[i].assoc));
 
-                        value = extract_value(req.data, "offset");
+                        value = extract_value(data, "offset");
                         /* Convert the value if we have one */
                         if(value != NULL)
-                                *offset = strtod(value, &nptr) / 1000;
+                                tmp_offset = strtod(value, &nptr) / 1000;
                         /* If value is null or no conversion was performed */
                         if(value == NULL || value==nptr) {
-                                printf("warning: unable to read server offset response.\n");
-                                status = max_state_alt(status, STATE_CRITICAL);
+                                if(verbose) printf("error: unable to read server offset response.\n");
                         } else {
-                                *offset_result = STATE_OK;
                                 if(verbose) printf("%g\n", *offset);
+                                if(*offset_result == STATE_UNKNOWN || fabs(tmp_offset) < fabs(*offset)) {
+                                        *offset = tmp_offset;
+                                        *offset_result = STATE_OK;
+                                } else {
+                                        /* Skip this one; move to the next */
+                                        continue;
+                                }
                         }
 
                         if(do_jitter) {
-                                /* first reset the pointers */
-                                value = NULL, nptr=NULL;
                                 /* get the jitter */
                                 if(verbose) {
-                                        printf("parsing jitter from peer %.2x: ", ntohs(peers[i].assoc));
+                                        printf("parsing %s from peer %.2x: ", strstr(getvar, "dispersion") != NULL ? "dispersion" : "jitter", ntohs(peers[i].assoc));
                                 }
-                                value = extract_value(req.data, strstr(getvar, "dispersion") != NULL ? "dispersion" : "jitter");
+                                value = extract_value(data, strstr(getvar, "dispersion") != NULL ? "dispersion" : "jitter");
                                 /* Convert the value if we have one */
                                 if(value != NULL)
                                         *jitter = strtod(value, &nptr);
                                 /* If value is null or no conversion was performed */
                                 if(value == NULL || value==nptr){
-                                        printf("warning: unable to read server jitter response.\n");
-                                        status = max_state_alt(status, STATE_UNKNOWN);
+                                        if(verbose) printf("error: unable to read server jitter response.\n");
+                                        *jitter = -1;
                                 } else {
                                         if(verbose) printf("%g\n", *jitter);
                                 }
                         }
 
                         if(do_stratum) {
-                                value = NULL;
                                 /* get the stratum */
                                 if(verbose) {
                                         printf("parsing stratum from peer %.2x: ", ntohs(peers[i].assoc));
                                 }
-                                value = extract_value(req.data, "stratum");
-                                if(value == NULL){
-                                        printf("warning: unable to read server stratum response.\n");
-                                        status = max_state_alt(status, STATE_UNKNOWN);
+                                value = extract_value(data, "stratum");
+                                if(value != NULL)
+                                        *stratum = strtol(value, &nptr, 10);
+                                if(value == NULL || value==nptr){
+                                        if(verbose) printf("error: unable to read server stratum response.\n");
+                                        *stratum = -1;
                                 } else {
-                                        *stratum = atoi(value);
                                         if(verbose) printf("%i\n", *stratum);
                                 }
                         }
@@ -503,8 +535,6 @@ int main(int argc, char *argv[]){
   double offset=0, jitter=0;
         char *result_line, *perfdata_line;
 
-        result = offset_result = STATE_OK;
-
         if (process_arguments (argc, argv) == ERROR)
                 usage4 (_("Could not parse arguments"));
 
@@ -518,7 +548,11 @@ int main(int argc, char *argv[]){
         /* set socket timeout */
         alarm (socket_timeout);
 
+  /* This returns either OK or WARNING (See comment preceeding ntp_request) */
         result = ntp_request(server_address, &offset, &offset_result, &jitter, &stratum);
+        if(offset_result == STATE_UNKNOWN)
+                result = STATE_CRITICAL;
+
         result = max_state_alt(result, get_status(fabs(offset), offset_thresholds));
 
         if(do_stratum)
@@ -610,7 +644,7 @@ void print_help(void){
 
         printf("\n");
         printf("%s\n", _("Examples:"));
-        printf(" %s\n", _("Normal offset check:"));
+        printf(" %s\n", _("Normal NTP server check:"));
         printf("  %s\n", ("./check_ntp_peer -H ntpserv -w 0.5 -c 1"));
         printf(" %s\n", _("Check jitter too, avoiding critical notifications if jitter isn't available"));
         printf(" %s\n", _("(See Notes above for more details on thresholds formats):"));