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 <resolv.h>
  19 #include <glob.h>
  20 #include <stdio.h>
  21 #include <time.h>
  22
  23 #include <libubus.h>
  24 #include <libubox/vlist.h>
  25 #include <libubox/uloop.h>
  26 #include <libubox/avl-cmp.h>
  27 #include <libubox/blobmsg_json.h>
  28
  29 #include "ubus.h"
  30 #include "dns.h"
  31 #include "service.h"
  32 #include "util.h"
  33 #include "interface.h"
  34 #include "announce.h"
  35
  36 enum {
  37         SERVICE_SERVICE,
  38         SERVICE_PORT,
  39         SERVICE_TXT,
  40         __SERVICE_MAX,
  41 };
  42
  43 struct service {
  44         struct vlist_node node;
  45
  46         time_t t;
  47
  48         const char *id;
  49         const char *service;
  50         const uint8_t *txt;
  51         int txt_len;
  52         int port;
  53         int active;
  54 };
  55
  56 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
  57         [SERVICE_SERVICE] = { .name = "service", .type = BLOBMSG_TYPE_STRING },
  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 static int service_init_announce;
  71
  72 static const char *
  73 service_name(const char *domain)
  74 {
  75         static char buffer[256];
  76
  77         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  78
  79         return buffer;
  80 }
  81
  82 static void
  83 service_add_ptr(const char *host, int ttl)
  84 {
  85         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  86
  87         if (len < 1)
  88                 return;
  89
  90         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
  91 }
  92
  93 static void
  94 service_add_srv(struct service *s, int ttl)
  95 {
  96         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
  97         int len = sizeof(*sd);
  98
  99         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
 100         if (len <= sizeof(*sd))
 101                 return;
 102
 103         sd->port = cpu_to_be16(s->port);
 104         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
 105 }
 106
 107 #define TOUT_LOOKUP     60
 108
 109 static time_t
 110 service_timeout(struct service *s)
 111 {
 112         time_t t = monotonic_time();
 113
 114         if (t - s->t <= TOUT_LOOKUP)
 115                 return 0;
 116
 117         return t;
 118 }
 119
 120 static void
 121 service_reply_single(struct interface *iface, struct service *s, const char *match, int ttl, int force)
 122 {
 123         const char *host = service_name(s->service);
 124         char *service = strstr(host, "._");
 125         time_t t = service_timeout(s);
 126
 127
 128         if (!force && (!s->active || !service || !t))
 129                 return;
 130
 131         service++;
 132
 133         if (match && strcmp(match, s->service))
 134                 return;
 135
 136         s->t = t;
 137
 138         dns_init_answer();
 139         service_add_ptr(service_name(s->service), ttl);
 140         dns_send_answer(iface, service);
 141
 142         dns_init_answer();
 143         service_add_srv(s, ttl);
 144         if (s->txt && s->txt_len)
 145                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 146         dns_send_answer(iface, host);
 147 }
 148
 149 void
 150 service_reply(struct interface *iface, const char *match, int ttl)
 151 {
 152         struct service *s;
 153
 154         vlist_for_each_element(&services, s, node)
 155                 service_reply_single(iface, s, match, ttl, 0);
 156
 157         if (match)
 158                 return;
 159
 160         if (ttl)
 161                 dns_reply_a(iface, ttl);
 162 }
 163
 164 void
 165 service_announce_services(struct interface *iface, const char *service, int ttl)
 166 {
 167         struct service *s;
 168         int tcp = 1;
 169
 170         if (!strcmp(service, sdudp))
 171                 tcp = 0;
 172         else if (strcmp(service, sdtcp))
 173                 return;
 174
 175         vlist_for_each_element(&services, s, node) {
 176                 if (!strstr(s->service, "._tcp") && tcp)
 177                         continue;
 178                 if (!strstr(s->service, "._udp") && !tcp)
 179                         continue;
 180                 s->t = 0;
 181                 if (ttl) {
 182                         dns_init_answer();
 183                         service_add_ptr(s->service, ttl);
 184                         if (tcp)
 185                                 dns_send_answer(iface, sdtcp);
 186                         else
 187                                 dns_send_answer(iface, sdudp);
 188                 }
 189                 service_reply(iface, s->service, ttl);
 190         }
 191 }
 192
 193 void
 194 service_announce(struct interface *iface, int ttl)
 195 {
 196         service_announce_services(iface, sdudp, ttl);
 197         service_announce_services(iface, sdtcp, ttl);
 198 }
 199
 200 static void
 201 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 202                struct vlist_node *node_old)
 203 {
 204         struct interface *iface;
 205         struct service *s;
 206
 207         if (!node_old) {
 208                 s = container_of(node_new, struct service, node);
 209                 if (service_init_announce)
 210                         vlist_for_each_element(&interfaces, iface, node) {
 211                                 s->t = 0;
 212                                 service_reply_single(iface, s, NULL, announce_ttl, 1);
 213                         }
 214                 return;
 215         }
 216
 217         s = container_of(node_old, struct service, node);
 218         if (!node_new && service_init_announce)
 219                 vlist_for_each_element(&interfaces, iface, node)
 220                         service_reply_single(iface, s, NULL, 0, 1);
 221         free(s);
 222 }
 223
 224 static void
 225 service_load_blob(struct blob_attr *b)
 226 {
 227         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 228         struct service *s;
 229         char *d_service, *d_id;
 230         uint8_t *d_txt;
 231         int rem2;
 232         int txt_len = 0;
 233
 234         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 235                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 236         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 237                 return;
 238
 239         if (_tb[SERVICE_SERVICE])
 240                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 241                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 242
 243         s = calloc_a(sizeof(*s),
 244                 &d_id, strlen(blobmsg_name(b)) + 1,
 245                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 246                 &d_txt, txt_len);
 247         if (!s)
 248                 return;
 249
 250         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 251         s->id = strcpy(d_id, blobmsg_name(b));
 252         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 253         s->active = 1;
 254         s->t = 0;
 255         s->txt_len = txt_len;
 256         s->txt = d_txt;
 257
 258         if (_tb[SERVICE_SERVICE])
 259                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 260                         int len = strlen(blobmsg_get_string(txt));
 261                         if (!len)
 262                                 return;
 263                         if (len > 0xff)
 264                                 len = 0xff;
 265                         *d_txt = len;
 266                         d_txt++;
 267                         memcpy(d_txt, blobmsg_get_string(txt), len);
 268                         d_txt += len;
 269                 }
 270
 271         vlist_add(&services, &s->node, s->id);
 272 }
 273
 274 static void
 275 service_load(char *path)
 276 {
 277         struct blob_attr *cur;
 278         glob_t gl;
 279         int i, rem;
 280
 281         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 282                 return;
 283
 284         for (i = 0; i < gl.gl_pathc; i++) {
 285                 blob_buf_init(&b, 0);
 286                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 287                         blob_for_each_attr(cur, b.head, rem)
 288                                 service_load_blob(cur);
 289         }
 290         globfree(&gl);
 291 }
 292
 293 static void
 294 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 295 {
 296         struct blob_attr *cur;
 297         int rem;
 298
 299         get_hostname();
 300
 301         vlist_update(&services);
 302         service_load("/tmp/run/mdns/*");
 303
 304         blob_for_each_attr(cur, msg, rem) {
 305                 struct blob_attr *cur2;
 306                 int rem2;
 307
 308                 blobmsg_for_each_attr(cur2, cur, rem2) {
 309                         struct blob_attr *cur3;
 310                         int rem3;
 311
 312                         if (strcmp(blobmsg_name(cur2), "instances"))
 313                                 continue;
 314
 315                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 316                                 struct blob_attr *cur4;
 317                                 int rem4;
 318                                 int running = 0;
 319
 320                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 321                                         const char *name = blobmsg_name(cur4);
 322
 323                                         if (!strcmp(name, "running")) {
 324                                                 running = blobmsg_get_bool(cur4);
 325                                         } else if (running && !strcmp(name, "data")) {
 326                                                 struct blob_attr *cur5;
 327                                                 int rem5;
 328
 329                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 330                                                         struct blob_attr *cur6;
 331                                                         int rem6;
 332
 333                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 334                                                                 continue;
 335
 336                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 337                                                                 service_load_blob(cur6);
 338                                                 }
 339                                                 break;
 340                                         }
 341                                 }
 342                         }
 343                 }
 344         }
 345         vlist_flush(&services);
 346 }
 347
 348 void
 349 service_init(int announce)
 350 {
 351         get_hostname();
 352
 353         service_init_announce = announce;
 354         ubus_service_list(service_init_cb);
 355 }
 356
 357 void
 358 service_cleanup(void)
 359 {
 360         vlist_flush(&services);
 361         blob_buf_free(&b);
 362 }