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, int rem)
52 DBG(2, "%s %s\n", dns_type_string(r->type), r->record);
54 avl_delete(&records, &r->avl);
65 cache_entry_free(struct cache_entry *s)
67 DBG(2, "%s\n", s->entry);
68 avl_delete(&entries, &s->avl);
73 cache_is_expired(time_t t, uint32_t ttl)
75 if (time(NULL) - t >= ttl)
82 cache_gc_timer(struct uloop_timeout *timeout)
84 struct cache_record *r, *p;
85 struct cache_entry *s, *t;
87 avl_for_each_element_safe(&records, r, avl, p)
88 if (cache_is_expired(r->time, r->ttl))
89 cache_record_free(r, 1);
91 avl_for_each_element_safe(&entries, s, avl, t) {
94 if (cache_is_expired(s->time, s->ttl))
98 uloop_timeout_set(timeout, 10000);
102 cache_load_services(void)
104 struct blob_attr *cur;
107 blob_buf_init(&b, 0);
109 if (!blobmsg_add_json_from_file(&b, "/lib/mdns/service-types"))
112 blob_for_each_attr(cur, b.head, rem)
113 kvlist_set(&types, blobmsg_name(cur), blobmsg_get_string(cur));
117 cache_lookup_name(const char *key)
119 return kvlist_get(&types, key);
125 kvlist_init(&types, kvlist_strlen);
126 avl_init(&entries, avl_strcmp, true, NULL);
127 avl_init(&records, avl_strcmp, true, NULL);
129 cache_gc.cb = cache_gc_timer;
130 uloop_timeout_set(&cache_gc, 10000);
131 cache_load_services();
136 void cache_cleanup(void)
138 struct cache_record *r, *p;
139 struct cache_entry *s, *t;
141 avl_for_each_element_safe(&records, r, avl, p)
142 cache_record_free(r, 1);
144 avl_for_each_element_safe(&entries, s, avl, t)
151 struct cache_entry *s;
153 avl_for_each_element(&entries, s, avl)
154 dns_send_question(&listener, s->entry, TYPE_PTR);
157 static struct cache_entry*
158 cache_entry(struct uloop_fd *u, char *entry, int hlen, int ttl)
160 struct cache_entry *s;
165 s = avl_find_element(&entries, entry, s, avl);
169 s = calloc_a(sizeof(*s),
170 &entry_buf, strlen(entry) + 1,
171 &host_buf, hlen ? hlen + 1 : 0);
173 s->avl.key = s->entry = strcpy(entry_buf, entry);
174 s->time = time(NULL);
178 s->host = strncpy(host_buf, s->entry, hlen);
180 type = strstr(entry_buf, "._");
185 avl_insert(&entries, &s->avl);
188 dns_send_question(u, entry, TYPE_PTR);
193 static struct cache_record*
194 cache_record_find(char *record, int type, int port, int rdlength, uint8_t *rdata)
196 struct cache_record *l = avl_find_element(&records, record, l, avl);
201 while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
202 struct cache_record *r = l;
204 l = avl_next_element(l, avl);
208 if (r->type == TYPE_TXT || (r->type == TYPE_SRV))
214 if (r->rdlength != rdlength)
217 if (!!r->rdata != !!rdata)
220 if (!r->rdata || !rdata || memcmp(r->rdata, rdata, rdlength))
230 cache_host_is_known(char *record)
232 struct cache_record *l = avl_find_element(&records, record, l, avl);
237 while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
238 struct cache_record *r = l;
240 l = avl_next_element(l, avl);
241 if ((r->type != TYPE_A) && (r->type != TYPE_AAAA))
250 cache_answer(struct uloop_fd *u, uint8_t *base, int blen, char *name, struct dns_answer *a, uint8_t *rdata)
252 struct dns_srv_data *dsd = (struct dns_srv_data *) rdata;
253 struct cache_record *r;
254 int port = 0, dlen = 0, tlen = 0, nlen, rdlength;
257 if (!(a->class & CLASS_IN))
267 if (dn_expand(base, base + blen, rdata, rdata_buffer, MAX_DATA_LEN) < 0) {
268 perror("process_answer/dn_expand");
272 DBG(1, "A -> %s %s %s\n", dns_type_string(a->type), name, rdata_buffer);
274 rdlength = strlen(rdata_buffer);
276 if (!strcmp(C_DNS_SD, name)) {
277 cache_entry(u, rdata_buffer, 0, a->ttl);
281 if ((rdlength < nlen) && (rdlength - nlen - 1 > 0))
284 cache_entry(u, rdata_buffer, rdlength - nlen - 1, a->ttl);
291 port = be16_to_cpu(dsd->port);
295 rdlength = a->rdlength;
299 memcpy(rdata_buffer, &rdata[1], rdlength);
300 rdata_buffer[rdlength] = rdata_buffer[rdlength + 1] = '\0';
302 p = &rdata_buffer[*rdata];
314 cache_entry(u, name, strlen(name), a->ttl);
315 if (a->rdlength != 4)
321 cache_entry(u, name, strlen(name), a->ttl);
322 if (a->rdlength != 16)
331 r = cache_record_find(name, a->type, port, dlen, rdata);
334 cache_record_free(r, 1);
335 DBG(1, "D -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
338 DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
346 r = malloc(sizeof(struct cache_record));
347 memset(r, 0, sizeof(struct cache_record));
348 r->avl.key = r->record = strdup(name);
353 r->time = time(NULL);
356 r->txt = malloc(tlen);
358 memcpy(r->txt, rdata_buffer, tlen);
362 r->rdata = malloc(dlen);
364 cache_record_free(r, 0);
367 memcpy(r->rdata, rdata, dlen);
370 if (avl_insert(&records, &r->avl))
371 cache_record_free(r, 0);
373 DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);