root/src/modules/dns.c

Revision 95b66901b3f49ed5ae2b6563f0a84290f949c220, 24.1 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 3 years ago)

fixes #359

  • Property mode set to 100644
Line 
1 /*
2  * Copyright (c) 2007, OmniTI Computer Consulting, Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are
7  * met:
8  *
9  *     * Redistributions of source code must retain the above copyright
10  *       notice, this list of conditions and the following disclaimer.
11  *     * Redistributions in binary form must reproduce the above
12  *       copyright notice, this list of conditions and the following
13  *       disclaimer in the documentation and/or other materials provided
14  *       with the distribution.
15  *     * Neither the name OmniTI Computer Consulting, Inc. nor the names
16  *       of its contributors may be used to endorse or promote products
17  *       derived from this software without specific prior written
18  *       permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32
33 #include "noit_defines.h"
34
35 #include <stdio.h>
36 #include <unistd.h>
37 #include <netdb.h>
38 #include <errno.h>
39 #include <assert.h>
40 #include <arpa/inet.h>
41
42 #include "noit_module.h"
43 #include "noit_check.h"
44 #include "noit_check_tools.h"
45 #include "utils/noit_log.h"
46 #include "utils/noit_atomic.h"
47 #include "udns/udns.h"
48
49 #define MAX_RR 256
50
51 static void eventer_dns_utm_fn(struct dns_ctx *, int, void *);
52 static int dns_eventer_callback(eventer_t, int, void *, struct timeval *);
53
54 static noit_log_stream_t nlerr = NULL;
55 static noit_log_stream_t nldeb = NULL;
56
57 static noit_hash_table dns_rtypes = NOIT_HASH_EMPTY;
58 static noit_hash_table dns_ctypes = NOIT_HASH_EMPTY;
59
60 static noit_hash_table dns_ctx_store = NOIT_HASH_EMPTY;
61 static pthread_mutex_t dns_ctx_store_lock;
62 typedef struct dns_ctx_handle {
63   char *ns;
64   struct dns_ctx *ctx;
65   noit_atomic32_t refcnt;
66   eventer_t e; /* evetner handling UDP traffic */
67   eventer_t timeout; /* the timeout managed by libudns */
68 } dns_ctx_handle_t;
69
70 static int cstring_cmp(const void *a, const void *b) {
71   return strcmp(*((const char **)a), *((const char **)b));
72 }
73
74 static dns_ctx_handle_t *default_ctx_handle = NULL;
75 static void dns_ctx_handle_free(void *vh) {
76   dns_ctx_handle_t *h = vh;
77   assert(h->timeout == NULL);
78   free(h->ns);
79   dns_close(h->ctx);
80   dns_free(h->ctx);
81 }
82 static dns_ctx_handle_t *dns_ctx_alloc(const char *ns) {
83   void *vh;
84   dns_ctx_handle_t *h = NULL;
85   pthread_mutex_lock(&dns_ctx_store_lock);
86   if(ns == NULL && default_ctx_handle != NULL) {
87     /* special case -- default context */
88     h = default_ctx_handle;
89     noit_atomic_inc32(&h->refcnt);
90     goto bail;
91   }
92   if(ns &&
93      noit_hash_retrieve(&dns_ctx_store, ns, strlen(ns), &vh)) {
94     h = (dns_ctx_handle_t *)vh;
95     noit_atomic_inc32(&h->refcnt);
96   }
97   else {
98     int failed = 0;
99     h = calloc(1, sizeof(*h));
100     h->ns = ns ? strdup(ns) : NULL;
101     h->ctx = dns_new(NULL);
102     if(dns_init(h->ctx, 0) != 0) failed++;
103     if(ns) {
104       if(dns_add_serv(h->ctx, NULL) < 0) failed++;
105       if(dns_add_serv(h->ctx, ns) < 0) failed++;
106     }
107     if(dns_open(h->ctx) < 0) failed++;
108     if(failed) {
109       noitL(nlerr, "dns_open failed\n");
110       free(h->ns);
111       free(h);
112       h = NULL;
113       goto bail;
114     }
115     dns_set_tmcbck(h->ctx, eventer_dns_utm_fn, h);
116     h->e = eventer_alloc();
117     h->e->mask = EVENTER_READ | EVENTER_EXCEPTION;
118     h->e->closure = h;
119     h->e->callback = dns_eventer_callback;
120     h->e->fd = dns_sock(h->ctx);
121     eventer_add(h->e);
122     h->refcnt = 1;
123     if(!ns)
124       default_ctx_handle = h;
125     else
126       noit_hash_store(&dns_ctx_store, h->ns, strlen(h->ns), h);
127   }
128  bail:
129   pthread_mutex_unlock(&dns_ctx_store_lock);
130   return h;
131 }
132 static void dns_ctx_release(dns_ctx_handle_t *h) {
133   if(h->ns == NULL) {
134     /* Special case for the default */
135     noit_atomic_dec32(&h->refcnt);
136     return;
137   }
138   pthread_mutex_lock(&dns_ctx_store_lock);
139   if(noit_atomic_dec32(&h->refcnt) == 0) {
140     /* I was the last one */
141     assert(noit_hash_delete(&dns_ctx_store, h->ns, strlen(h->ns),
142                             NULL, dns_ctx_handle_free));
143   }
144   pthread_mutex_unlock(&dns_ctx_store_lock);
145 }
146
147 static noit_hash_table active_events = NOIT_HASH_EMPTY;
148 static pthread_mutex_t active_events_lock;
149
150 typedef struct dns_check_info {
151   stats_t current;
152   int timed_out;
153   noit_module_t *self;
154   noit_check_t *check;
155   eventer_t timeout_event;
156   dns_ctx_handle_t *h;
157   char *error;
158   int nrr;
159   int sort;
160
161   /* These make up the query itself */
162   unsigned char dn[DNS_MAXDN];
163   enum dns_class query_ctype;
164   enum dns_type query_rtype;
165 } dns_check_info_t;
166
167 static int __isactive_ci(struct dns_check_info *ci) {
168   void *u;
169   int exists = 0;
170   pthread_mutex_lock(&active_events_lock);
171   if(noit_hash_retrieve(&active_events, (void *)&ci, sizeof(ci), &u))
172     exists = 1;
173   pthread_mutex_unlock(&active_events_lock);
174   return exists;
175 }
176 static void __activate_ci(struct dns_check_info *ci) {
177   struct dns_check_info **holder;
178   holder = calloc(1, sizeof(*holder));
179   *holder = ci;
180   pthread_mutex_lock(&active_events_lock);
181   assert(noit_hash_store(&active_events, (void *)holder, sizeof(*holder), ci));
182   pthread_mutex_unlock(&active_events_lock);
183 }
184 static void __deactivate_ci(struct dns_check_info *ci) {
185   pthread_mutex_lock(&active_events_lock);
186   assert(noit_hash_delete(&active_events, (void *)&ci, sizeof(ci), free, NULL));
187   pthread_mutex_unlock(&active_events_lock);
188 }
189
190 static void dns_check_log_results(struct dns_check_info *ci) {
191   struct timeval duration;
192   double rtt;
193
194   gettimeofday(&ci->current.whence, NULL);
195   sub_timeval(ci->current.whence, ci->check->last_fire_time, &duration);
196   rtt = duration.tv_sec * 1000.0 + duration.tv_usec / 1000.0;
197   ci->current.duration = rtt;
198
199   ci->current.state = (ci->error || ci->nrr == 0) ? NP_BAD : NP_GOOD;
200   ci->current.available = ci->timed_out ? NP_UNAVAILABLE : NP_AVAILABLE;
201   if(ci->error) {
202     ci->current.status = strdup(ci->error);
203   }
204   else if(!ci->current.status) {
205     char buff[48];
206     snprintf(buff, sizeof(buff), "%d %s",
207              ci->nrr, ci->nrr == 1 ? "record" : "records");
208     ci->current.status = strdup(buff);
209     noit_stats_set_metric(&ci->current, "rtt", METRIC_DOUBLE,
210                           ci->timed_out ? NULL : &rtt);
211   }
212
213   noit_check_set_stats(ci->self, ci->check, &ci->current);
214   if(ci->error) free(ci->error);
215   if(ci->current.status) free(ci->current.status);
216   ci->error = NULL;
217   memset(&ci->current, 0, sizeof(ci->current));
218 }
219
220 static int dns_interpolate_inaddr_arpa(char *buff, int len, const char *ip) {
221   const char *b, *e;
222   char *o;
223   unsigned char dn[DNS_MAXDN];
224   int il;
225   struct {
226     struct in_addr addr;
227     struct in6_addr addr6;
228   } a;
229   /* This function takes a dot delimited string as input and
230    * reverses the parts split on dot.
231    */
232   if (dns_pton(AF_INET, ip, &a.addr) > 0) {
233     dns_a4todn(&a.addr, 0, dn, sizeof(dn));
234     dns_dntop(dn,buff,len);
235     return strlen(buff);
236   }
237   else if (dns_pton(AF_INET6, ip, &a.addr6) > 0) {
238     dns_a6todn(&a.addr6, 0, dn, sizeof(dn));
239     dns_dntop(dn,buff,len);
240     return strlen(buff);
241   }
242
243   o = buff;
244   il = strlen(ip);
245   if(len <= il) {
246     /* not enough room for ip and '\0' */
247     if(len > 0) buff[0] = '\0';
248     return 0;
249   }
250   e = ip + il;
251   b = e - 1;
252   while(b >= ip) {
253     const char *term;
254     while(b >= ip && *b != '.') b--;  /* Rewind to previous part */
255     term = b + 1; /* term is one ahead, we went past it */
256     if(term != e) memcpy(o, term, e - term); /* no sense in copying nothing */
257     o += e - term; /* advance the term length */
258     e = b;
259     b = e - 1;
260     if(e >= ip) *o++ = '.'; /* we must be at . */
261   }
262   *o = '\0';
263   assert((o - buff) == il);
264   return o - buff;
265 }
266 static int dns_interpolate_reverse_ip(char *buff, int len, const char *ip) {
267 #define IN4ADDRARPA_LEN 13 // strlen(".in-addr.arpa");
268 #define IN6ADDRARPA_LEN 9 // strlen(".ip6.arpa");
269   dns_interpolate_inaddr_arpa(buff,len,ip);
270   if(len > IN4ADDRARPA_LEN &&
271      !strcmp(buff+len-IN4ADDRARPA_LEN, ".in-addr.arpa"))
272     buff[len-IN4ADDRARPA_LEN] = '\0';
273   else if((len > IN6ADDRARPA_LEN) &&
274           !strcmp(buff+len-IN6ADDRARPA_LEN, ".ip6.arpa"))
275     buff[len-IN6ADDRARPA_LEN] = '\0';
276   return strlen(buff);
277 }
278
279 static int dns_module_init(noit_module_t *self) {
280   const struct dns_nameval *nv;
281   struct dns_ctx *pctx;
282   int i;
283   pthread_mutex_init(&dns_ctx_store_lock, NULL);
284   pthread_mutex_init(&active_events_lock, NULL);
285   /* HASH the rr types */
286   for(i=0, nv = dns_type_index(i); nv->name; nv = dns_type_index(++i))
287     noit_hash_store(&dns_rtypes,
288                     nv->name, strlen(nv->name),
289                     (void *)nv);
290   /* HASH the class types */
291   for(i=0, nv = dns_class_index(i); nv->name; nv = dns_class_index(++i))
292     noit_hash_store(&dns_ctypes,
293                     nv->name, strlen(nv->name),
294                     (void *)nv);
295
296   noit_check_interpolate_register_oper_fn("inaddrarpa",
297                                           dns_interpolate_inaddr_arpa);
298   noit_check_interpolate_register_oper_fn("reverseip",
299                                           dns_interpolate_reverse_ip);
300
301   if (dns_init(NULL, 0) < 0 || (pctx = dns_new(NULL)) == NULL) {
302     noitL(nlerr, "Unable to initialize dns subsystem\n");
303     return -1;
304   }
305   dns_free(pctx);
306   if(dns_ctx_alloc(NULL) == NULL) {
307     noitL(nlerr, "Error setting up default dns resolver context.\n");
308     return -1;
309   }
310   return 0;
311 }
312
313 static void dns_check_cleanup(noit_module_t *self, noit_check_t *check) {
314 }
315
316 static int dns_eventer_callback(eventer_t e, int mask, void *closure,
317                                 struct timeval *now) {
318   dns_ctx_handle_t *h = closure;
319   dns_ioevent(h->ctx, now->tv_sec);
320   return EVENTER_READ | EVENTER_EXCEPTION;
321 }
322
323 static int dns_check_timeout(eventer_t e, int mask, void *closure,
324                              struct timeval *now) {
325   struct dns_check_info *ci;
326   ci = closure;
327   ci->timeout_event = NULL;
328   ci->check->flags &= ~NP_RUNNING;
329   dns_check_log_results(ci);
330   __deactivate_ci(ci);
331   return 0;
332 }
333
334 static int dns_invoke_timeouts(eventer_t e, int mask, void *closure,
335                                struct timeval *now) {
336   dns_ctx_handle_t *h = closure;
337   dns_timeouts(h->ctx, 0, now->tv_sec);
338   return 0;
339 }
340 static void eventer_dns_utm_fn(struct dns_ctx *ctx, int timeout, void *data) {
341   dns_ctx_handle_t *h = data;
342   eventer_t e = NULL, newe = NULL;
343   if(ctx == NULL) e = eventer_remove(h->timeout);
344   else {
345     assert(h->ctx == ctx);
346     if(timeout < 0) e = eventer_remove(h->timeout);
347     else {
348       newe = eventer_alloc();
349       newe->mask = EVENTER_TIMER;
350       newe->callback = dns_invoke_timeouts;
351       newe->closure = h;
352       gettimeofday(&newe->whence, NULL);
353       newe->whence.tv_sec += timeout;
354     }
355   }
356   if(e) eventer_free(e);
357   if(newe) eventer_add(newe);
358   h->timeout = newe;
359 }
360
361 static char *encode_txt(char *dst, const unsigned char *src, int len) {
362   int i;
363   for(i=0; i<len; i++) {
364     if(src[i] >= 127 || src[i] <= 31) {
365       snprintf(dst, 4, "\\%02x", src[i]);
366       dst += 3;
367     }
368     else if(src[i] == '\\') {
369       *dst++ = '\\';
370       *dst++ = '\\';
371     }
372     else {
373       *dst++ = (char)src[i];
374     }
375   }
376   *dst = '\0';
377   return dst;
378 }
379
380 static void decode_rr(struct dns_check_info *ci, struct dns_parse *p,
381                       struct dns_rr *rr, char **output) {
382   char buff[DNS_MAXDN], *txt_str = buff, *c;
383   u_int32_t ttl, vu;
384   int32_t vs;
385   int totalsize;
386   const unsigned char *pkt = p->dnsp_pkt;
387   const unsigned char *end = p->dnsp_end;
388   const unsigned char *dptr = rr->dnsrr_dptr;
389   const unsigned char *dend = rr->dnsrr_dend;
390   unsigned char *dn = rr->dnsrr_dn;
391   const unsigned char *tmp;
392
393   /* Not interested unless it is the answer to my exact question */
394   if (!dns_dnequal(ci->dn, dn)) return;
395
396   if (!p->dnsp_rrl && !rr->dnsrr_dn[0] && rr->dnsrr_typ == DNS_T_OPT) {
397     /* We don't handle EDNS0 OPT records */
398     goto decode_err;
399   }
400   noitL(nldeb, "%s. %u %s %s\n", dns_dntosp(dn), rr->dnsrr_ttl,
401         dns_classname(rr->dnsrr_cls),
402         dns_typename(rr->dnsrr_typ));
403
404   ttl = rr->dnsrr_ttl;
405   noit_stats_set_metric(&ci->current, "ttl", METRIC_UINT32, &ttl);
406
407   switch(rr->dnsrr_typ) {
408    case DNS_T_A:
409     if (rr->dnsrr_dsz != 4) goto decode_err;
410     snprintf(buff, sizeof(buff), "%d.%d.%d.%d",
411              dptr[0], dptr[1], dptr[2], dptr[3]);
412     break;
413
414    case DNS_T_AAAA:
415     if (rr->dnsrr_dsz != 16) goto decode_err;
416     inet_ntop(AF_INET6, dptr, buff, sizeof(buff));
417     break;
418
419    case DNS_T_TXT:
420     totalsize = 0;
421     for(tmp = dptr; tmp < dend; totalsize += *tmp, tmp += *tmp + 1)
422       if(tmp + *tmp + 1 > dend) goto decode_err;
423     /* worst case: every character escaped + '\0' */
424     txt_str = alloca(totalsize * 3 + 1);
425     if(!txt_str) goto decode_err;
426     c = txt_str;
427     for(tmp = dptr; tmp < dend; tmp += *tmp + 1)
428       c = encode_txt(c, tmp+1, *tmp);
429     break;
430
431    case DNS_T_MX:
432     snprintf(buff, sizeof(buff), "%d ", dns_get16(dptr));
433     tmp = dptr + 2;
434     if(dns_getdn(pkt, &tmp, end, dn, DNS_MAXDN) <= 0 || tmp != dend)
435       goto decode_err;
436     dns_dntop(dn, buff + strlen(buff), sizeof(buff) - strlen(buff));
437     break;
438
439    case DNS_T_SOA:
440      if(dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN) <= 0) goto decode_err;
441      dns_dntop(dn, buff, sizeof(buff));
442      noit_stats_set_metric(&ci->current, "name-server", METRIC_STRING, buff);
443      if(dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN) <= 0) goto decode_err;
444      dns_dntop(dn, buff, sizeof(buff));
445      noit_stats_set_metric(&ci->current, "email-addr", METRIC_STRING, buff);
446      if(dptr + 5 * sizeof(u_int32_t) != dend) goto decode_err;
447      vu = dns_get32(dptr); dptr += sizeof(u_int32_t);
448      noit_stats_set_metric(&ci->current, "serial", METRIC_UINT32, &vu);
449      /* the serial is what we elect to store as the "answer" as text...
450       * because it rarely changes and that seems the most interesting thing
451       * to track change-log-style.
452       */
453      snprintf(buff, sizeof(buff), "%u", vu);
454      vs = dns_get32(dptr); dptr += sizeof(int32_t);
455      noit_stats_set_metric(&ci->current, "refresh", METRIC_UINT32, &vs);
456      vs = dns_get32(dptr); dptr += sizeof(int32_t);
457      noit_stats_set_metric(&ci->current, "retry", METRIC_UINT32, &vs);
458      vs = dns_get32(dptr); dptr += sizeof(int32_t);
459      noit_stats_set_metric(&ci->current, "expiry", METRIC_UINT32, &vs);
460      vs = dns_get32(dptr); dptr += sizeof(int32_t);
461      noit_stats_set_metric(&ci->current, "minimum", METRIC_UINT32, &vs);
462      break;
463
464    case DNS_T_CNAME:
465    case DNS_T_PTR:
466    case DNS_T_NS:
467    case DNS_T_MB:
468    case DNS_T_MD:
469    case DNS_T_MF:
470    case DNS_T_MG:
471    case DNS_T_MR:
472     if(dns_getdn(pkt, &dptr, end, dn, DNS_MAXDN) <= 0) goto decode_err;
473     dns_dntop(dn, buff, sizeof(buff));
474     break;
475
476    default:
477     break;
478   }
479   if(*output) {
480     int newlen = strlen(*output) + strlen(", ") + strlen(buff) + 1;
481     char *newstr;
482     newstr = malloc(newlen);
483     snprintf(newstr, newlen, "%s, %s", *output, buff);
484     free(*output);
485     *output = newstr;
486   }
487   else
488     *output = strdup(txt_str);
489   ci->nrr++;
490   return;
491
492  decode_err:
493   ci->error = strdup("RR decode error");
494   return;
495 }
496
497 static void dns_cb(struct dns_ctx *ctx, void *result, void *data) {
498   int r = dns_status(ctx);
499   int len, i;
500   struct dns_check_info *ci = data;
501   struct dns_parse p;
502   struct dns_rr rr;
503   unsigned nrr;
504   unsigned char dn[DNS_MAXDN];
505   const unsigned char *pkt, *cur, *end;
506   char *result_str[MAX_RR] = { NULL };
507   char *result_combined = NULL;
508
509   /* If out ci isn't active, we must have timed out already */
510   if(!__isactive_ci(ci)) {
511     if(result) free(result);
512     return;
513   }
514
515   ci->timed_out = 0;
516   /* If we don't have a result, explode */
517   if (!result) {
518     ci->error = strdup(dns_strerror(r));
519     goto cleanup;
520   }
521
522   /* Process the packet */
523   pkt = result; end = pkt + r; cur = dns_payload(pkt);
524   dns_getdn(pkt, &cur, end, dn, sizeof(dn));
525   dns_initparse(&p, NULL, pkt, cur, end);
526   p.dnsp_qcls = 0;
527   p.dnsp_qtyp = 0;
528   nrr = 0;
529
530   while((r = dns_nextrr(&p, &rr)) > 0) {
531     if (!dns_dnequal(dn, rr.dnsrr_dn)) continue;
532     if ((ci->query_ctype == DNS_C_ANY || ci->query_ctype == rr.dnsrr_cls) &&
533         (ci->query_rtype == DNS_T_ANY || ci->query_rtype == rr.dnsrr_typ))
534       ++nrr;
535     else if (rr.dnsrr_typ == DNS_T_CNAME && !nrr) {
536       if (dns_getdn(pkt, &rr.dnsrr_dptr, end,
537                     p.dnsp_dnbuf, sizeof(p.dnsp_dnbuf)) <= 0 ||
538           rr.dnsrr_dptr != rr.dnsrr_dend) {
539         ci->error = strdup("protocol error");
540         break;
541       }
542       else {
543         int32_t on = 1;
544         /* This actually updates what we're looking for */
545         dns_dntodn(p.dnsp_dnbuf, ci->dn, sizeof(dn));
546         noit_stats_set_metric(&ci->current, "cname", METRIC_INT32, &on);
547
548         /* Now follow the leader */
549         noitL(nldeb, "%s. CNAME %s.\n", dns_dntosp(dn),
550               dns_dntosp(p.dnsp_dnbuf));
551         dns_dntodn(p.dnsp_dnbuf, dn, sizeof(dn));
552         noitL(nldeb, " ---> '%s'\n", dns_dntosp(dn));
553       }
554     }
555   }
556   if (!r && !nrr) {
557     ci->error = strdup("no data");
558   }
559
560   dns_rewind(&p, NULL);
561   p.dnsp_qtyp = ci->query_rtype == DNS_T_ANY ? 0 : ci->query_rtype;
562   p.dnsp_qcls = ci->query_ctype == DNS_C_ANY ? 0 : ci->query_ctype;
563   while(dns_nextrr(&p, &rr) && ci->nrr < MAX_RR)
564     decode_rr(ci, &p, &rr, &result_str[ci->nrr]);
565   if(ci->sort)
566     qsort(result_str, ci->nrr, sizeof(*result_str), cstring_cmp);
567   /* calculate the length and allocate on the stack */
568   len = 0;
569   for(i=0; i<ci->nrr; i++) len += strlen(result_str[i]) + 2;
570   result_combined = alloca(len);
571   result_combined[0] = '\0';
572   /* string it together */
573   len = 0;
574   for(i=0; i<ci->nrr; i++) {
575     int slen;
576     if(i) { memcpy(result_combined + len, ", ", 2); len += 2; }
577     slen = strlen(result_str[i]);
578     memcpy(result_combined + len, result_str[i], slen);
579     len += slen;
580     result_combined[len] = '\0';
581     free(result_str[i]); /* free as we go */
582   }
583   noit_stats_set_metric(&ci->current, "answer", METRIC_STRING, result_combined);
584
585  cleanup:
586   if(result) free(result);
587   if(ci->timeout_event) {
588     eventer_t e = eventer_remove(ci->timeout_event);
589     ci->timeout_event = NULL;
590     if(e) eventer_free(e);
591   }
592   ci->check->flags &= ~NP_RUNNING;
593   dns_check_log_results(ci);
594   __deactivate_ci(ci);
595 }
596
597 static int dns_check_send(noit_module_t *self, noit_check_t *check) {
598   void *vnv_pair = NULL;
599   struct dns_nameval *nv_pair;
600   eventer_t newe;
601   struct timeval p_int, now;
602   struct dns_check_info *ci = check->closure;
603   const char *config_val;
604   const char *rtype = NULL;
605   const char *nameserver = NULL;
606   const char *want_sort = NULL;
607   const char *ctype = "IN";
608   const char *query = NULL;
609   char interpolated_nameserver[1024];
610   char interpolated_query[1024];
611   noit_hash_table check_attrs_hash = NOIT_HASH_EMPTY;
612
613   gettimeofday(&now, NULL);
614   memcpy(&check->last_fire_time, &now, sizeof(now));
615   ci->current.state = NP_BAD;
616   ci->current.available = NP_UNAVAILABLE;
617   ci->timed_out = 1;
618   ci->nrr = 0;
619   ci->sort = 1;
620
621   if(!strcmp(check->name, "in-addr.arpa") ||
622      (strlen(check->name) >= sizeof("::in-addr.arpa") - 1 &&
623       !strcmp(check->name + strlen(check->name) - sizeof("::in-addr.arpa") + 1,
624               "::in-addr.arpa"))) {
625     /* in-addr.arpa defaults:
626      *   nameserver to NULL
627      *   rtype to PTR
628      *   query to %[:inaddrarpa:target]
629      */
630     nameserver = NULL;
631     rtype = "PTR";
632     query = "%[:inaddrarpa:target_ip]";
633   }
634   else {
635     nameserver = "%[target_ip]";
636     rtype = "A";
637     query = "%[name]";
638   }
639 #define CONFIG_OVERRIDE(a) \
640   if(noit_hash_retr_str(check->config, #a, strlen(#a), \
641                         &config_val) && \
642      strlen(config_val) > 0) \
643     a = config_val
644   CONFIG_OVERRIDE(ctype);
645   CONFIG_OVERRIDE(nameserver);
646   CONFIG_OVERRIDE(rtype);
647   CONFIG_OVERRIDE(query);
648   CONFIG_OVERRIDE(want_sort);
649   if(nameserver && !strcmp(nameserver, "default")) nameserver = NULL;
650   if(want_sort && strcasecmp(want_sort, "on") && strcasecmp(want_sort, "true"))
651     ci->sort = 0;
652
653   noit_check_make_attrs(check, &check_attrs_hash);
654
655   if(nameserver) {
656     noit_check_interpolate(interpolated_nameserver,
657                            sizeof(interpolated_nameserver),
658                            nameserver,
659                            &check_attrs_hash, check->config);
660     nameserver = interpolated_nameserver;
661   }
662   if(query) {
663     noit_check_interpolate(interpolated_query,
664                            sizeof(interpolated_query),
665                            query,
666                            &check_attrs_hash, check->config);
667     query = interpolated_query;
668   }
669   noit_hash_destroy(&check_attrs_hash, NULL, NULL);
670
671   check->flags |= NP_RUNNING;
672   noitL(nldeb, "dns_check_send(%p,%s,%s,%s,%s,%s)\n",
673         self, check->target, nameserver ? nameserver : "default",
674         query ? query : "null", ctype, rtype);
675
676   __activate_ci(ci);
677   /* If this ci has a handle and it isn't the one we need,
678    * we should release it
679    */
680   if(ci->h &&
681      ((ci->h->ns == NULL && nameserver != NULL) ||
682       (ci->h->ns != NULL && nameserver == NULL) ||
683       (ci->h->ns && strcmp(ci->h->ns, nameserver)))) {
684     dns_ctx_release(ci->h);
685     ci->h = NULL;
686   }
687   /* use the cached one, unless we don't have one */
688   if(!ci->h) ci->h = dns_ctx_alloc(nameserver);
689   if(!ci->h) ci->error = strdup("bad nameserver");
690
691   /* Lookup out class */
692   if(!noit_hash_retrieve(&dns_ctypes, ctype, strlen(ctype),
693                          &vnv_pair)) {
694     if(ci->error) free(ci->error);
695     ci->error = strdup("bad class");
696   }
697   else {
698     nv_pair = (struct dns_nameval *)vnv_pair;
699     ci->query_ctype = nv_pair->val;
700   }
701   /* Lookup out rr type */
702   if(!noit_hash_retrieve(&dns_rtypes, rtype, strlen(rtype),
703                          &vnv_pair)) {
704     if(ci->error) free(ci->error);
705     ci->error = strdup("bad rr type");
706   }
707   else {
708     nv_pair = (struct dns_nameval *)vnv_pair;
709     ci->query_rtype = nv_pair->val;
710   }
711
712   if(!ci->error) {
713     /* Submit the query */
714     int abs;
715     if(!dns_ptodn(query, strlen(query), ci->dn, sizeof(ci->dn), &abs) ||
716        !dns_submit_dn(ci->h->ctx, ci->dn, ci->query_ctype, ci->query_rtype,
717                       abs | DNS_NOSRCH, NULL, dns_cb, ci)) {
718       ci->error = strdup("submission error");
719     }
720     else {
721       dns_timeouts(ci->h->ctx, -1, now.tv_sec);
722     }
723   }
724
725   /* we could have completed by now... if so, we've nothing to do */
726
727   if(!__isactive_ci(ci)) return 0;
728
729   if(ci->error) {
730     /* Errors here are easy, fail and avoid scheduling a timeout */
731     ci->check->flags &= ~NP_RUNNING;
732     dns_check_log_results(ci);
733     __deactivate_ci(ci);
734     return 0;
735   }
736
737   newe = eventer_alloc();
738   newe->mask = EVENTER_TIMER;
739   gettimeofday(&now, NULL);
740   p_int.tv_sec = check->timeout / 1000;
741   p_int.tv_usec = (check->timeout % 1000) * 1000;
742   add_timeval(now, p_int, &newe->whence);
743   newe->closure = ci;
744   newe->callback = dns_check_timeout;
745   ci->timeout_event = newe;
746   eventer_add(newe);
747
748   return 0;
749 }
750
751 static int dns_initiate_check(noit_module_t *self, noit_check_t *check,
752                               int once, noit_check_t *cause) {
753   struct dns_check_info *ci;
754   if(!check->closure)
755     check->closure = calloc(1, sizeof(struct dns_check_info));
756   ci = check->closure;
757   ci->check = check;
758   ci->self = self;
759   INITIATE_CHECK(dns_check_send, self, check);
760   return 0;
761 }
762
763 static int dns_config(noit_module_t *self, noit_hash_table *options) {
764   return 0;
765 }
766
767 static int dns_onload(noit_image_t *self) {
768   nlerr = noit_log_stream_find("error/dns");
769   nldeb = noit_log_stream_find("debug/dns");
770   if(!nlerr) nlerr = noit_stderr;
771   if(!nldeb) nldeb = noit_debug;
772   eventer_name_callback("dns/dns_eventer_callback", dns_eventer_callback);
773   eventer_name_callback("dns/dns_check_timeout", dns_check_timeout);
774   eventer_name_callback("dns/dns_invoke_timeouts", dns_invoke_timeouts);
775   return 0;
776 }
777
778 #include "dns.xmlh"
779 noit_module_t dns = {
780   {
781     NOIT_MODULE_MAGIC,
782     NOIT_MODULE_ABI_VERSION,
783     "dns",
784     "DNS RR checker",
785     dns_xml_description,
786     dns_onload
787   },
788   dns_config,
789   dns_module_init,
790   dns_initiate_check,
791   dns_check_cleanup
792 };
793
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