bd361324348d5fc65e024271b93f2c48b2ee4381
[project/mdnsd.git] / service.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 #include <sys/types.h>
15 #include <arpa/nameser.h>
16 #include <sys/socket.h>
17
18 #include <ifaddrs.h>
19 #include <resolv.h>
20 #include <glob.h>
21 #include <stdio.h>
22 #include <time.h>
23
24 #include <uci.h>
25 #include <uci_blob.h>
26
27 #include <libubox/vlist.h>
28 #include <libubox/uloop.h>
29 #include <libubox/avl-cmp.h>
30 #include <libubox/blobmsg_json.h>
31
32 #include "dns.h"
33 #include "service.h"
34 #include "util.h"
35 #include "interface.h"
36 #include "announce.h"
37
38 enum {
39         SERVICE_PORT,
40         SERVICE_TXT,
41         __SERVICE_MAX,
42 };
43
44 struct service {
45         struct vlist_node node;
46
47         time_t t;
48
49         const char *service;
50         const char *daemon;
51         const uint8_t *txt;
52         int txt_len;
53         int port;
54         int active;
55 };
56
57 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
58         [SERVICE_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT32 },
59         [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
60 };
61
62 static void
63 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
64                struct vlist_node *node_old);
65
66 static struct blob_buf b;
67 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
68 static char *sdudp =  "_services._dns-sd._udp.local";
69 static char *sdtcp =  "_services._dns-sd._tcp.local";
70
71 static const char *
72 service_name(const char *domain)
73 {
74         static char buffer[256];
75
76         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
77
78         return buffer;
79 }
80
81 static void
82 service_add_ptr(const char *host, int ttl)
83 {
84         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
85
86         if (len < 1)
87                 return;
88
89         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
90 }
91
92 static void
93 service_add_srv(struct service *s, int ttl)
94 {
95         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
96         int len = sizeof(*sd);
97
98         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
99         if (len <= sizeof(*sd))
100                 return;
101
102         sd->port = cpu_to_be16(s->port);
103         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
104 }
105
106 #define TOUT_LOOKUP     60
107
108 static int
109 service_timeout(struct service *s)
110 {
111         time_t t = time(NULL);
112
113         if (t - s->t <= TOUT_LOOKUP)
114                 return 0;
115
116         s->t = t;
117
118         return 1;
119 }
120
121 void
122 service_reply_a(struct interface *iface, int type, int ttl)
123 {
124         struct ifaddrs *ifap, *ifa;
125         struct sockaddr_in *sa;
126         struct sockaddr_in6 *sa6;
127         char *addr;
128
129         getifaddrs(&ifap);
130
131         dns_init_answer();
132         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
133                 if (strcmp(ifa->ifa_name, iface->name))
134                         continue;
135                 if (ifa->ifa_addr->sa_family==AF_INET) {
136                         sa = (struct sockaddr_in *) ifa->ifa_addr;
137                         addr = inet_ntoa(sa->sin_addr);
138                         printf("Interface: %s\tAddress4: %s\n", ifa->ifa_name, addr);
139                         dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
140                 }
141                 if (ifa->ifa_addr->sa_family==AF_INET6) {
142                         uint8_t ll_prefix[] = {0xfe, 0x80 };
143                         char buf[64] = { 0 };
144                         sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
145                         if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2)) {
146                                 if (inet_ntop(AF_INET6, &sa6->sin6_addr, buf, 64))
147                                         printf("Interface: %s\tAddress6: %s\n", ifa->ifa_name, buf);
148                                 dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
149                         }
150                 }
151         }
152         dns_send_answer(iface, mdns_hostname_local);
153
154         freeifaddrs(ifap);
155 }
156
157 void
158 service_reply(struct interface *iface, const char *match, int ttl)
159 {
160         struct service *s;
161
162         vlist_for_each_element(&services, s, node) {
163                 const char *host = service_name(s->service);
164                 char *service = strstr(host, "._");
165
166                 if (!s->active || !service || !service_timeout(s))
167                         continue;
168
169                 service++;
170
171                 if (match && strcmp(match, s->service))
172                         continue;
173
174                 dns_init_answer();
175                 service_add_ptr(service_name(s->service), ttl);
176                 dns_send_answer(iface, service);
177
178                 dns_init_answer();
179                 service_add_srv(s, ttl);
180                 if (s->txt && s->txt_len)
181                         dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
182                 dns_send_answer(iface, host);
183         }
184
185         if (match)
186                 return;
187
188         service_reply_a(iface, TYPE_A, ttl);
189 }
190
191 void
192 service_announce_services(struct interface *iface, const char *service)
193 {
194         struct service *s;
195         int tcp = 1;
196
197         if (!strcmp(service, sdudp))
198                 tcp = 0;
199         else if (strcmp(service, sdtcp))
200                 return;
201
202         vlist_for_each_element(&services, s, node) {
203                 if (!strstr(s->service, "._tcp") && tcp)
204                         continue;
205                 if (!strstr(s->service, "._udp") && !tcp)
206                         continue;
207                 s->t = 0;
208                 dns_init_answer();
209                 service_add_ptr(s->service, announce_ttl);
210                 if (tcp)
211                         dns_send_answer(iface, sdtcp);
212                 else
213                         dns_send_answer(iface, sdudp);
214                 service_reply(iface, s->service, announce_ttl);
215         }
216 }
217
218 void
219 service_announce(struct interface *iface)
220 {
221         service_announce_services(iface, sdudp);
222         service_announce_services(iface, sdtcp);
223 }
224
225 static void
226 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
227                struct vlist_node *node_old)
228 {
229         struct service *s;
230
231         if (!node_old)
232                 return;
233
234         s = container_of(node_old, struct service, node);
235         free(s);
236 }
237
238 static void
239 service_load(char *path)
240 {
241         struct blob_attr *txt, *cur, *_tb[__SERVICE_MAX];
242         int rem, i;
243         glob_t gl;
244
245         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
246                 return;
247
248         for (i = 0; i < gl.gl_pathc; i++) {
249                 blob_buf_init(&b, 0);
250
251                 if (!blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
252                         continue;
253                 blob_for_each_attr(cur, b.head, rem) {
254                         struct service *s;
255                         char *d_service, *d_daemon;
256                         uint8_t *d_txt;
257                         int rem2;
258                         int txt_len = 0;
259
260                         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
261                                 _tb, blobmsg_data(cur), blobmsg_data_len(cur));
262                         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_TXT])
263                                 continue;
264
265                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
266                                 txt_len += 1 + strlen(blobmsg_get_string(txt));
267
268                         s = calloc_a(sizeof(*s),
269                                 &d_daemon, strlen(gl.gl_pathv[i]) + 1,
270                                 &d_service, strlen(blobmsg_name(cur)) + 1,
271                                 &d_txt, txt_len);
272                         if (!s)
273                                 continue;
274
275                         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
276                         s->service = strcpy(d_service, blobmsg_name(cur));
277                         s->daemon = strcpy(d_daemon, gl.gl_pathv[i]);
278                         s->active = 1;
279                         s->t = 0;
280                         s->txt_len = txt_len;
281                         s->txt = d_txt;
282
283                         blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
284                                 int len = strlen(blobmsg_get_string(txt));
285                                 if (!len)
286                                         continue;
287                                 if (len > 0xff)
288                                         len = 0xff;
289                                 *d_txt = len;
290                                 d_txt++;
291                                 memcpy(d_txt, blobmsg_get_string(txt), len);
292                                 d_txt += len;
293                         }
294
295                         vlist_add(&services, &s->node, s->service);
296                 }
297         }
298 }
299
300 void
301 service_init(void)
302 {
303         get_hostname();
304
305         vlist_update(&services);
306         service_load("/tmp/run/mdnsd/*");
307         vlist_flush(&services);
308 }
309
310 void
311 service_cleanup(void)
312 {
313         vlist_flush(&services);
314         blob_buf_free(&b);
315 }