2 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
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
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.
15 #include <sys/types.h>
23 #include <sys/types.h>
24 #include <sys/socket.h>
25 #include <netinet/in.h>
26 #include <arpa/inet.h>
27 #include <asm/byteorder.h>
28 #include <arpa/nameser.h>
32 #include <libubox/usock.h>
33 #include <libubox/uloop.h>
34 #include <libubox/avl-cmp.h>
35 #include <libubox/blobmsg_json.h>
36 #include <libubox/kvlist.h>
43 static struct uloop_timeout cache_gc;
44 struct avl_tree records, entries, hosts;
45 static struct blob_buf b;
47 static struct kvlist types;
50 cache_record_free(struct cache_record *r)
52 DBG(2, "%s %s\n", dns_type_string(r->type), r->record);
53 avl_delete(&records, &r->avl);
58 cache_entry_free(struct cache_entry *s)
60 DBG(2, "%s\n", s->entry);
61 avl_delete(&entries, &s->avl);
66 cache_is_expired(time_t t, uint32_t ttl)
68 if (time(NULL) - t >= ttl)
75 cache_gc_timer(struct uloop_timeout *timeout)
77 struct cache_record *r, *p;
78 struct cache_entry *s, *t;
80 avl_for_each_element_safe(&records, r, avl, p)
81 if (cache_is_expired(r->time, r->ttl))
84 avl_for_each_element_safe(&entries, s, avl, t) {
87 if (cache_is_expired(s->time, s->ttl))
91 uloop_timeout_set(timeout, 10000);
95 cache_load_services(void)
97 struct blob_attr *cur;
100 blob_buf_init(&b, 0);
102 if (!blobmsg_add_json_from_file(&b, "/lib/mdns/service-types"))
105 blob_for_each_attr(cur, b.head, rem)
106 kvlist_set(&types, blobmsg_name(cur), blobmsg_get_string(cur));
110 cache_lookup_name(const char *key)
112 return kvlist_get(&types, key);
118 kvlist_init(&types, kvlist_strlen);
119 avl_init(&entries, avl_strcmp, true, NULL);
120 avl_init(&records, avl_strcmp, true, NULL);
122 cache_gc.cb = cache_gc_timer;
123 uloop_timeout_set(&cache_gc, 10000);
124 cache_load_services();
129 void cache_cleanup(void)
131 struct cache_record *r, *p;
132 struct cache_entry *s, *t;
134 avl_for_each_element_safe(&records, r, avl, p)
135 cache_record_free(r);
137 avl_for_each_element_safe(&entries, s, avl, t)
144 struct cache_entry *s;
146 avl_for_each_element(&entries, s, avl)
147 dns_send_question(&listener, s->entry, TYPE_PTR);
150 static struct cache_entry*
151 cache_entry(struct uloop_fd *u, char *entry, int hlen, int ttl)
153 struct cache_entry *s;
158 s = avl_find_element(&entries, entry, s, avl);
162 s = calloc_a(sizeof(*s),
163 &entry_buf, strlen(entry) + 1,
164 &host_buf, hlen ? hlen + 1 : 0);
166 s->avl.key = s->entry = strcpy(entry_buf, entry);
167 s->time = time(NULL);
171 s->host = strncpy(host_buf, s->entry, hlen);
173 type = strstr(entry_buf, "._");
178 avl_insert(&entries, &s->avl);
181 dns_send_question(u, entry, TYPE_PTR);
186 static struct cache_record*
187 cache_record_find(char *record, int type, int port, int rdlength, uint8_t *rdata)
189 struct cache_record *l = avl_find_element(&records, record, l, avl);
194 while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
195 struct cache_record *r = l;
197 l = avl_next_element(l, avl);
201 if (r->type == TYPE_TXT || (r->type == TYPE_SRV))
207 if (r->rdlength != rdlength)
210 if (!!r->rdata != !!rdata)
213 if (!r->rdata || !rdata || memcmp(r->rdata, rdata, rdlength))
223 cache_host_is_known(char *record)
225 struct cache_record *l = avl_find_element(&records, record, l, avl);
230 while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
231 struct cache_record *r = l;
233 l = avl_next_element(l, avl);
234 if ((r->type != TYPE_A) && (r->type != TYPE_AAAA))
243 cache_answer(struct uloop_fd *u, uint8_t *base, int blen, char *name, struct dns_answer *a, uint8_t *rdata)
245 struct dns_srv_data *dsd = (struct dns_srv_data *) rdata;
246 struct cache_record *r;
247 int port = 0, dlen = 0, tlen = 0, nlen, rdlength;
250 void *rdata_ptr, *txt_ptr;
252 if (!(a->class & CLASS_IN))
262 if (dn_expand(base, base + blen, rdata, rdata_buffer, MAX_DATA_LEN) < 0) {
263 perror("process_answer/dn_expand");
267 DBG(1, "A -> %s %s %s\n", dns_type_string(a->type), name, rdata_buffer);
269 rdlength = strlen(rdata_buffer);
271 if (!strcmp(C_DNS_SD, name)) {
272 cache_entry(u, rdata_buffer, 0, a->ttl);
276 if ((rdlength < nlen) && (rdlength - nlen - 1 > 0))
279 cache_entry(u, rdata_buffer, rdlength - nlen - 1, a->ttl);
286 port = be16_to_cpu(dsd->port);
290 rdlength = a->rdlength;
294 memcpy(rdata_buffer, &rdata[1], rdlength);
295 rdata_buffer[rdlength] = rdata_buffer[rdlength + 1] = '\0';
297 p = &rdata_buffer[*rdata];
309 cache_entry(u, name, strlen(name), a->ttl);
310 if (a->rdlength != 4)
316 cache_entry(u, name, strlen(name), a->ttl);
317 if (a->rdlength != 16)
326 r = cache_record_find(name, a->type, port, dlen, rdata);
329 cache_record_free(r);
330 DBG(1, "D -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
333 DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
341 r = calloc_a(sizeof(*r),
342 &name_buf, strlen(name) + 1,
346 r->avl.key = r->record = strcpy(name_buf, name);
351 r->time = time(NULL);
354 r->txt = memcpy(txt_ptr, rdata_buffer, tlen);
357 r->rdata = memcpy(rdata_ptr, rdata, dlen);
359 if (avl_insert(&records, &r->avl))
362 DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);