Fix IPv6 read
[project/mdnsd.git] / cache.c
1 /*
2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU Lesser General Public License version 2.1
6  * as published by the Free Software Foundation
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13
14 #define _GNU_SOURCE
15 #include <sys/types.h>
16 #include <sys/stat.h>
17
18 #include <fcntl.h>
19 #include <time.h>
20 #include <stdio.h>
21 #include <string.h>
22 #include <unistd.h>
23 #include <sys/types.h>
24 #include <sys/socket.h>
25 #include <netinet/in.h>
26 #include <arpa/inet.h>
27 #include <arpa/nameser.h>
28 #include <resolv.h>
29 #include <time.h>
30
31 #include <libubox/usock.h>
32 #include <libubox/uloop.h>
33 #include <libubox/avl-cmp.h>
34 #include <libubox/blobmsg_json.h>
35 #include <libubox/kvlist.h>
36 #include <libubus.h>
37
38 #include "cache.h"
39 #include "util.h"
40 #include "dns.h"
41 #include "interface.h"
42
43 static struct uloop_timeout cache_gc;
44 struct avl_tree services;
45 static AVL_TREE(records, avl_strcmp, true, NULL);
46
47 static void
48 cache_record_free(struct cache_record *r)
49 {
50         DBG(2, "%s %s\n", dns_type_string(r->type), r->record);
51         avl_delete(&records, &r->avl);
52         free(r);
53 }
54
55 static void
56 cache_service_free(struct cache_service *s)
57 {
58         DBG(2, "%s\n", s->entry);
59         avl_delete(&services, &s->avl);
60         free(s);
61 }
62
63 static int
64 cache_is_expired(time_t t, uint32_t ttl, int frac)
65 {
66         if (monotonic_time() - t >= ttl * frac / 100)
67                 return 1;
68
69         return 0;
70 }
71
72 static void
73 cache_gc_timer(struct uloop_timeout *timeout)
74 {
75         struct cache_record *r, *p;
76         struct cache_service *s, *t;
77
78         avl_for_each_element_safe(&records, r, avl, p)
79                 if (cache_is_expired(r->time, r->ttl, 100))
80                         cache_record_free(r);
81
82         avl_for_each_element_safe(&services, s, avl, t) {
83                 if (!s->host)
84                         continue;
85                 if (!cache_is_expired(s->time, s->ttl, s->refresh))
86                         continue;
87                 if (s->refresh >= 100) {
88                         cache_service_free(s);
89                         continue;
90                 }
91                 s->refresh += 50;
92                 dns_send_question(s->iface, s->entry, TYPE_PTR, 1);
93         }
94
95         uloop_timeout_set(timeout, 10000);
96 }
97
98 int
99 cache_init(void)
100 {
101         avl_init(&services, avl_strcmp, true, NULL);
102
103         cache_gc.cb = cache_gc_timer;
104         uloop_timeout_set(&cache_gc, 10000);
105
106         return 0;
107 }
108
109 void cache_cleanup(struct interface *iface)
110 {
111         struct cache_record *r, *p;
112         struct cache_service *s, *t;
113
114         avl_for_each_element_safe(&services, s, avl, t)
115                 if (!iface || iface == s->iface)
116                         cache_service_free(s);
117
118         avl_for_each_element_safe(&records, r, avl, p)
119                 if (!iface || iface == r->iface)
120                         cache_record_free(r);
121 }
122
123 void
124 cache_scan(void)
125 {
126         struct interface *iface;
127         struct cache_service *s;
128
129         vlist_for_each_element(&interfaces, iface, node)
130                 avl_for_each_element(&services, s, avl)
131                         dns_send_question(iface, s->entry, TYPE_PTR, 1);
132 }
133
134 static struct cache_service*
135 cache_service(struct interface *iface, char *entry, int hlen, int ttl)
136 {
137         struct cache_service *s, *t;
138         char *entry_buf;
139         char *host_buf;
140         char *type;
141
142         avl_for_each_element_safe(&services, s, avl, t)
143                 if (!strcmp(s->entry, entry)) {
144                         s->refresh = 50;
145                         s->time = monotonic_time();
146                         return s;
147                 }
148
149         s = calloc_a(sizeof(*s),
150                 &entry_buf, strlen(entry) + 1,
151                 &host_buf, hlen ? hlen + 1 : 0);
152
153         s->avl.key = s->entry = strcpy(entry_buf, entry);
154         s->time = monotonic_time();
155         s->ttl = ttl;
156         s->iface = iface;
157         s->refresh = 50;
158
159         if (hlen)
160                 s->host = strncpy(host_buf, s->entry, hlen);
161
162         type = strstr(entry_buf, "._");
163         if (type)
164                 type++;
165         if (type)
166                 s->avl.key = type;
167         avl_insert(&services, &s->avl);
168
169         if (!hlen)
170                 dns_send_question(iface, entry, TYPE_PTR, !iface->multicast);
171
172         return s;
173 }
174
175 static struct cache_record*
176 cache_record_find(char *record, int type, int port, int rdlength, uint8_t *rdata)
177 {
178         struct cache_record *l = avl_find_element(&records, record, l, avl);
179
180         if (!l)
181                 return NULL;
182
183         while (l && l->record && !strcmp(l->record, record)) {
184                 struct cache_record *r = l;
185
186                 l = avl_next_element(l, avl);
187                 if (r->type != type)
188                         continue;
189
190                 if (r->type == TYPE_TXT || (r->type == TYPE_SRV))
191                         return r;
192
193                 if (r->port != port)
194                         continue;
195
196                 if (r->rdlength != rdlength)
197                         continue;
198
199                 if (!!r->rdata != !!rdata)
200                         continue;
201
202                 if (!r->rdata || !rdata || memcmp(r->rdata, rdata, rdlength))
203                         continue;
204
205                 return r;
206         }
207
208         return NULL;
209 }
210
211 int
212 cache_host_is_known(char *record)
213 {
214         struct cache_record *l = avl_find_element(&records, record, l, avl);
215
216         if (!l)
217                 return 0;
218
219         while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
220                 struct cache_record *r = l;
221
222                 l = avl_next_element(l, avl);
223                 if ((r->type != TYPE_A) && (r->type != TYPE_AAAA))
224                         continue;
225                 return 1;
226         }
227
228         return 0;
229 }
230
231 void
232 cache_answer(struct interface *iface, uint8_t *base, int blen, char *name, struct dns_answer *a, uint8_t *rdata, int flush)
233 {
234         struct dns_srv_data *dsd = (struct dns_srv_data *) rdata;
235         struct cache_record *r;
236         int port = 0, dlen = 0, tlen = 0, nlen, rdlength;
237         char *p = NULL;
238         char *name_buf;
239         void *rdata_ptr, *txt_ptr;
240         int host_len = 0;
241         static char *rdata_buffer = (char *) mdns_buf;
242         time_t now = monotonic_time();
243
244         nlen = strlen(name);
245
246         switch (a->type) {
247         case TYPE_PTR:
248                 if (a->rdlength < 2)
249                         return;
250
251                 if (dn_expand(base, base + blen, rdata, rdata_buffer, MAX_DATA_LEN) < 0) {
252                         perror("process_answer/dn_expand");
253                         return;
254                 }
255
256                 DBG(1, "A -> %s %s %s ttl:%d\n", dns_type_string(a->type), name, rdata_buffer, a->ttl);
257
258                 rdlength = strlen(rdata_buffer);
259
260                 if (strcmp(C_DNS_SD, name) != 0 &&
261                     nlen + 1 < rdlength && !strcmp(rdata_buffer + rdlength - nlen, name))
262                         host_len = rdlength - nlen - 1;
263
264                 cache_service(iface, rdata_buffer, host_len, a->ttl);
265
266                 dlen = strlen(rdata_buffer) + 1;
267                 rdata = (uint8_t*)rdata_buffer;
268                 break;
269
270         case TYPE_SRV:
271                 if (a->rdlength < 8)
272                         return;
273
274                 port = be16_to_cpu(dsd->port);
275                 memcpy(rdata_buffer, dsd, sizeof(*dsd));
276                 if (dn_expand(base, base + blen, (const uint8_t*)&dsd[1],
277                                 &rdata_buffer[sizeof(*dsd)], MAX_DATA_LEN - sizeof(*dsd)) < 0) {
278                         perror("process_answer/dn_expand");
279                         return;
280                 }
281                 dlen = sizeof(*dsd) + strlen(&rdata_buffer[sizeof(*dsd)]) + 1;
282                 rdata = (uint8_t*)rdata_buffer;
283                 break;
284
285         case TYPE_TXT:
286                 rdlength = a->rdlength;
287                 if (rdlength <= 2)
288                         return;
289
290                 memcpy(rdata_buffer, &rdata[1], rdlength);
291                 rdata_buffer[rdlength] = rdata_buffer[rdlength + 1] = '\0';
292                 tlen = rdlength + 1;
293                 p = &rdata_buffer[*rdata];
294
295                 do {
296                         uint8_t v = *p;
297
298                         *p = '\0';
299                         if (v && p + v < &rdata_buffer[rdlength])
300                                 p += v + 1;
301                 } while (*p);
302                 break;
303
304         case TYPE_A:
305                 cache_service(iface, name, strlen(name), a->ttl);
306                 if (a->rdlength != 4)
307                         return;
308                 dlen = 4;
309                 break;
310
311         case TYPE_AAAA:
312                 cache_service(iface, name, strlen(name), a->ttl);
313                 if (a->rdlength != 16)
314                         return;
315                 dlen = 16;
316                 break;
317
318         default:
319                 return;
320         }
321
322         r = cache_record_find(name, a->type, port, dlen, rdata);
323         if (r) {
324                 if (!a->ttl) {
325                         DBG(1, "D -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
326                         r->time = now + 1 - r->ttl;
327                 } else {
328                         r->ttl = a->ttl;
329                         r->time = now;
330                         DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
331                 }
332                 return;
333         }
334
335         if (!a->ttl)
336                 return;
337
338         r = calloc_a(sizeof(*r),
339                 &name_buf, strlen(name) + 1,
340                 &txt_ptr, tlen,
341                 &rdata_ptr, dlen);
342
343         r->avl.key = r->record = strcpy(name_buf, name);
344         r->type = a->type;
345         r->ttl = a->ttl;
346         r->port = port;
347         r->rdlength = dlen;
348         r->time = now;
349         r->iface = iface;
350
351         if (tlen)
352                 r->txt = memcpy(txt_ptr, rdata_buffer, tlen);
353
354         if (dlen)
355                 r->rdata = memcpy(rdata_ptr, rdata, dlen);
356
357         if (avl_insert(&records, &r->avl))
358                 free(r);
359         else
360                 DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
361 }
362
363 void
364 cache_dump_records(struct blob_buf *buf, const char *name)
365 {
366         struct cache_record *r, *last, *next;
367         const char *txt;
368         char buffer[INET6_ADDRSTRLEN];
369
370         last = avl_last_element(&records, last, avl);
371         for (r = avl_find_element(&records, name, r, avl); r; r = next) {
372                 switch (r->type) {
373                 case TYPE_TXT:
374                         if (r->txt && strlen(r->txt)) {
375                                 txt = r->txt;
376                                 do {
377                                         blobmsg_add_string(buf, "txt", txt);
378                                         txt = &txt[strlen(txt) + 1];
379                                 } while (*txt);
380                         }
381                         break;
382
383                 case TYPE_SRV:
384                         if (r->port)
385                                 blobmsg_add_u32(buf, "port", r->port);
386                         break;
387
388                 case TYPE_A:
389                         if ((r->rdlength == 4) && inet_ntop(AF_INET, r->rdata, buffer, INET6_ADDRSTRLEN))
390                                 blobmsg_add_string(buf, "ipv4", buffer);
391                         break;
392
393                 case TYPE_AAAA:
394                         if ((r->rdlength == 16) && inet_ntop(AF_INET6, r->rdata, buffer, INET6_ADDRSTRLEN))
395                                 blobmsg_add_string(buf, "ipv6", buffer);
396                         break;
397                 }
398
399                 if (r == last)
400                         break;
401
402                 next = avl_next_element(r, avl);
403                 if (strcmp(r->record, next->record) != 0)
404                         break;
405         }
406 }
407
408 void
409 cache_dump_recursive(struct blob_buf *b, const char *name, uint16_t type, struct interface *iface)
410 {
411         time_t now = monotonic_time();
412         for (struct cache_record *r = avl_find_ge_element(&records, name, r, avl);
413                         r && !strcmp(r->record, name);
414                         r = !avl_is_last(&records, &r->avl) ? avl_next_element(r, avl) : NULL) {
415                 int32_t ttl = r->ttl - (now - r->time);
416                 if (ttl <= 0 || (iface && iface->ifindex != r->iface->ifindex) ||
417                                 (type != TYPE_ANY && type != r->type))
418                         continue;
419
420                 const char *txt;
421                 char buf[INET6_ADDRSTRLEN];
422                 void *k = blobmsg_open_table(b, NULL), *l;
423                 const struct dns_srv_data *dsd = (const struct dns_srv_data*)r->rdata;
424
425                 blobmsg_add_string(b, "name", r->record);
426                 blobmsg_add_string(b, "type", dns_type_string(r->type));
427                 blobmsg_add_u32(b, "ttl", ttl);
428
429                 switch (r->type) {
430                 case TYPE_TXT:
431                         if ((txt = r->txt) && strlen(txt)) {
432                                 l = blobmsg_open_array(b, "data");
433                                 do {
434                                         blobmsg_add_string(b, NULL, txt);
435                                         txt = &txt[strlen(txt) + 1];
436                                 } while (*txt);
437                                 blobmsg_close_array(b, l);
438                         }
439                         break;
440
441                 case TYPE_SRV:
442                         if (r->rdlength > sizeof(*dsd)) {
443                                 blobmsg_add_u32(b, "priority", be16_to_cpu(dsd->priority));
444                                 blobmsg_add_u32(b, "weight", be16_to_cpu(dsd->weight));
445                                 blobmsg_add_u32(b, "port", be16_to_cpu(dsd->port));
446                                 blobmsg_add_string(b, "target", (const char*)&dsd[1]);
447                         }
448                         break;
449
450                 case TYPE_PTR:
451                         if (r->rdlength > 0)
452                                 blobmsg_add_string(b, "target", (const char*)r->rdata);
453                         break;
454
455                 case TYPE_A:
456                         if ((r->rdlength == 4) && inet_ntop(AF_INET, r->rdata, buf, sizeof(buf)))
457                                 blobmsg_add_string(b, "target", buf);
458                         break;
459
460                 case TYPE_AAAA:
461                         if ((r->rdlength == 16) && inet_ntop(AF_INET6, r->rdata, buf, sizeof(buf)))
462                                 blobmsg_add_string(b, "target", buf);
463                         break;
464                 }
465
466                 blobmsg_close_table(b, k);
467
468
469                 if (r->type == TYPE_PTR) {
470                         cache_dump_recursive(b, (const char*)r->rdata, TYPE_SRV, iface);
471                         cache_dump_recursive(b, (const char*)r->rdata, TYPE_TXT, iface);
472                 }
473
474                 if (r->type == TYPE_SRV) {
475                         cache_dump_recursive(b, (const char*)&dsd[1], TYPE_A, iface);
476                         cache_dump_recursive(b, (const char*)&dsd[1], TYPE_AAAA, iface);
477                 }
478         }
479 }