+/*
+ * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <time.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <asm/byteorder.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+#include <time.h>
+
+#include <libubox/usock.h>
+#include <libubox/uloop.h>
+#include <libubox/avl-cmp.h>
+#include <libubox/blobmsg_json.h>
+#include <libubus.h>
+
+#include "cache.h"
+#include "util.h"
+#include "dns.h"
+
+static struct uloop_timeout cache_gc;
+struct avl_tree records, entries, types, hosts;
+static struct blob_buf b;
+
+static void
+cache_record_free(struct cache_record *r, int rem)
+{
+ DBG(2, "%s %s\n", dns_type_string(r->type), r->record);
+ if (rem)
+ avl_delete(&records, &r->avl);
+ if (r->record)
+ free(r->record);
+ if (r->rdata)
+ free(r->rdata);
+ if (r->txt)
+ free(r->txt);
+ free(r);
+}
+
+static void
+cache_entry_free(struct cache_entry *s)
+{
+ DBG(2, "%s\n", s->entry);
+ avl_delete(&entries, &s->avl);
+ if (s->host)
+ free(s->host);
+ if (s->entry)
+ free(s->entry);
+ free(s);
+}
+
+static int
+cache_is_expired(time_t t, uint32_t ttl)
+{
+ if (time(NULL) - t >= ttl)
+ return 1;
+
+ return 0;
+}
+
+static void
+cache_gc_timer(struct uloop_timeout *timeout)
+{
+ struct cache_record *r, *p;
+ struct cache_entry *s, *t;
+
+ avl_for_each_element_safe(&records, r, avl, p)
+ if (cache_is_expired(r->time, r->ttl))
+ cache_record_free(r, 1);
+
+ avl_for_each_element_safe(&entries, s, avl, t) {
+ if (!s->host)
+ continue;
+ if (cache_is_expired(s->time, s->ttl))
+ cache_entry_free(s);
+ }
+
+ uloop_timeout_set(timeout, 10000);
+}
+
+static void
+cache_load_services(void)
+{
+ struct blob_attr *cur;
+ int rem;
+
+ blob_buf_init(&b, 0);
+
+ if (!blobmsg_add_json_from_file(&b, "/lib/mdns/service-types"))
+ return;
+
+ blob_for_each_attr(cur, b.head, rem) {
+ struct cache_type *t = malloc(sizeof(struct cache_type));
+
+ if (!t)
+ continue;
+ t->avl.key = t->key = strdup(blobmsg_name(cur));
+ t->val = strdup(blobmsg_get_string(cur));
+ avl_insert(&types, &t->avl);
+ }
+}
+
+char*
+cache_lookup_name(const char *key)
+{
+ struct cache_type *t;
+
+ t = avl_find_element(&types, key, t, avl);
+ if (!t)
+ return NULL;
+
+ return t->val;
+}
+
+int
+cache_init(void)
+{
+ avl_init(&entries, avl_strcmp, true, NULL);
+ avl_init(&types, avl_strcmp, false, NULL);
+ avl_init(&records, avl_strcmp, true, NULL);
+
+ cache_gc.cb = cache_gc_timer;
+ uloop_timeout_set(&cache_gc, 10000);
+ cache_load_services();
+
+ return 0;
+}
+
+void cache_cleanup(void)
+{
+ struct cache_record *r, *p;
+ struct cache_entry *s, *t;
+
+ avl_for_each_element_safe(&records, r, avl, p)
+ cache_record_free(r, 1);
+
+ avl_for_each_element_safe(&entries, s, avl, t)
+ cache_entry_free(s);
+}
+
+void
+cache_scan(void)
+{
+ struct cache_entry *s;
+
+ avl_for_each_element(&entries, s, avl)
+ dns_send_question(&listener, s->entry, TYPE_PTR);
+}
+
+static struct cache_entry*
+cache_find_entry(char *entry)
+{
+ struct cache_entry *s;
+
+ avl_for_each_element(&entries, s, avl)
+ if (!strcmp(s->entry, entry))
+ return s;
+ return NULL;
+}
+
+static struct cache_entry*
+cache_entry(struct uloop_fd *u, char *entry, int hlen, int ttl)
+{
+ struct cache_entry *s;
+ char *type;
+
+ s = cache_find_entry(entry);
+ if (s)
+ return s;
+
+ s = malloc(sizeof(struct cache_entry));
+ memset(s, 0, sizeof(struct cache_entry));
+ s->avl.key = s->entry = strdup(entry);
+ s->time = time(NULL);
+ s->ttl = ttl;
+
+ if (hlen)
+ s->host = strndup(s->entry, hlen);
+ type = strstr(s->entry, "._");
+ if (type)
+ type++;
+ if (type)
+ s->avl.key = type;
+ avl_insert(&entries, &s->avl);
+
+ if (!hlen)
+ dns_send_question(u, entry, TYPE_PTR);
+
+ return s;
+}
+
+static struct cache_record*
+cache_record_find(char *record, int type, int port, int rdlength, uint8_t *rdata)
+{
+ struct cache_record *l = avl_find_element(&records, record, l, avl);
+
+ if (!l)
+ return NULL;
+
+ while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
+ struct cache_record *r = l;
+
+ l = avl_next_element(l, avl);
+ if (r->type != type)
+ continue;
+
+ if (r->type == TYPE_TXT || (r->type == TYPE_SRV))
+ return r;
+
+ if (r->port != port)
+ continue;
+
+ if (r->rdlength != rdlength)
+ continue;
+
+ if (!!r->rdata != !!rdata)
+ continue;
+
+ if (!r->rdata || !rdata || memcmp(r->rdata, rdata, rdlength))
+ continue;
+
+ return r;
+ }
+
+ return NULL;
+}
+
+int
+cache_host_is_known(char *record)
+{
+ struct cache_record *l = avl_find_element(&records, record, l, avl);
+
+ if (!l)
+ return 0;
+
+ while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
+ struct cache_record *r = l;
+
+ l = avl_next_element(l, avl);
+ if ((r->type != TYPE_A) && (r->type != TYPE_AAAA))
+ continue;
+ return 1;
+ }
+
+ return 0;
+}
+
+void
+cache_answer(struct uloop_fd *u, uint8_t *base, int blen, char *name, struct dns_answer *a, uint8_t *rdata)
+{
+ struct dns_srv_data *dsd = (struct dns_srv_data *) rdata;
+ struct cache_record *r;
+ int port = 0, dlen = 0, tlen = 0, nlen, rdlength;
+ char *p = NULL;
+
+ if (!(a->class & CLASS_IN))
+ return;
+
+ nlen = strlen(name);
+
+ switch (a->type) {
+ case TYPE_PTR:
+ if (a->rdlength < 2)
+ return;
+
+ if (dn_expand(base, base + blen, rdata, rdata_buffer, MAX_DATA_LEN) < 0) {
+ perror("process_answer/dn_expand");
+ return;
+ }
+
+ DBG(1, "A -> %s %s %s\n", dns_type_string(a->type), name, rdata_buffer);
+
+ rdlength = strlen(rdata_buffer);
+
+ if (!strcmp(C_DNS_SD, name)) {
+ cache_entry(u, rdata_buffer, 0, a->ttl);
+ return;
+ }
+
+ if ((rdlength < nlen) && (rdlength - nlen - 1 > 0))
+ return;
+
+ cache_entry(u, rdata_buffer, rdlength - nlen - 1, a->ttl);
+ return;
+
+ case TYPE_SRV:
+ if (a->rdlength < 8)
+ return;
+
+ port = be16_to_cpu(dsd->port);
+ break;
+
+ case TYPE_TXT:
+ rdlength = a->rdlength;
+ if (rdlength <= 2)
+ return;
+
+ memcpy(rdata_buffer, &rdata[1], rdlength);
+ rdata_buffer[rdlength] = rdata_buffer[rdlength + 1] = '\0';
+ tlen = rdlength + 1;
+ p = &rdata_buffer[*rdata];
+
+ do {
+ uint8_t v = *p;
+
+ *p = '\0';
+ if (v)
+ p += v + 1;
+ } while (*p);
+ break;
+
+ case TYPE_A:
+ cache_entry(u, name, strlen(name), a->ttl);
+ if (a->rdlength != 4)
+ return;
+ dlen = 4;
+ break;
+
+ case TYPE_AAAA:
+ cache_entry(u, name, strlen(name), a->ttl);
+ if (a->rdlength != 16)
+ return;
+ dlen = 16;
+ break;
+
+ default:
+ return;
+ }
+
+ r = cache_record_find(name, a->type, port, dlen, rdata);
+ if (r) {
+ if (!a->ttl) {
+ cache_record_free(r, 1);
+ DBG(1, "D -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
+ } else {
+ r->ttl = a->ttl;
+ DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
+ }
+ return;
+ }
+
+ if (!a->ttl)
+ return;
+
+ r = malloc(sizeof(struct cache_record));
+ memset(r, 0, sizeof(struct cache_record));
+ r->avl.key = r->record = strdup(name);
+ r->type = a->type;
+ r->ttl = a->ttl;
+ r->port = port;
+ r->rdlength = dlen;
+ r->time = time(NULL);
+
+ if (tlen) {
+ r->txt = malloc(tlen);
+ if (r->txt)
+ memcpy(r->txt, rdata_buffer, tlen);
+ }
+
+ if (dlen) {
+ r->rdata = malloc(dlen);
+ if (!r->rdata) {
+ cache_record_free(r, 0);
+ return;
+ }
+ memcpy(r->rdata, rdata, dlen);
+ }
+
+ if (avl_insert(&records, &r->avl))
+ cache_record_free(r, 0);
+ else
+ DBG(1, "A -> %s %s ttl:%d\n", dns_type_string(r->type), r->record, r->ttl);
+}
projects / project / mdnsd.git / commitdiff