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 char *sdudp =  "_services._dns-sd._udp.local";
  69 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, 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         s->t = t;
 134
 135         dns_init_answer();
 136         service_add_ptr(service_name(s->service), ttl);
 137         dns_send_answer(iface, service);
 138
 139         dns_init_answer();
 140         service_add_srv(s, ttl);
 141         if (s->txt && s->txt_len)
 142                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 143         dns_send_answer(iface, host);
 144 }
 145
 146 void
 147 service_reply(struct interface *iface, const char *match, int ttl)
 148 {
 149         struct service *s;
 150
 151         vlist_for_each_element(&services, s, node) {
 152                 if (!match || !strcmp(s->service, match))
 153                         service_reply_single(iface, s, ttl, 0);
 154         }
 155 }
 156
 157 void
 158 service_announce_services(struct interface *iface, int tcp, int ttl)
 159 {
 160         struct service *s;
 161
 162         vlist_for_each_element(&services, s, node) {
 163                 if (!strstr(s->service, "._tcp") && tcp)
 164                         continue;
 165                 if (!strstr(s->service, "._udp") && !tcp)
 166                         continue;
 167                 s->t = 0;
 168                 if (ttl) {
 169                         dns_init_answer();
 170                         service_add_ptr(s->service, ttl);
 171                         if (tcp)
 172                                 dns_send_answer(iface, sdtcp);
 173                         else
 174                                 dns_send_answer(iface, sdudp);
 175                 }
 176                 service_reply_single(iface, s, ttl, 0);
 177         }
 178 }
 179
 180 void
 181 service_announce(struct interface *iface, int ttl)
 182 {
 183         service_announce_services(iface, 0, ttl);
 184         service_announce_services(iface, 1, ttl);
 185 }
 186
 187 static void
 188 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 189                struct vlist_node *node_old)
 190 {
 191         struct interface *iface;
 192         struct service *s;
 193
 194         if (!node_old) {
 195                 s = container_of(node_new, struct service, node);
 196                 if (service_init_announce)
 197                         vlist_for_each_element(&interfaces, iface, node) {
 198                                 s->t = 0;
 199                                 service_reply_single(iface, s, announce_ttl, 1);
 200                         }
 201                 return;
 202         }
 203
 204         s = container_of(node_old, struct service, node);
 205         if (!node_new && service_init_announce)
 206                 vlist_for_each_element(&interfaces, iface, node)
 207                         service_reply_single(iface, s, 0, 1);
 208         free(s);
 209 }
 210
 211 static void
 212 service_load_blob(struct blob_attr *b)
 213 {
 214         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 215         struct service *s;
 216         char *d_service, *d_id;
 217         uint8_t *d_txt;
 218         int rem2;
 219         int txt_len = 0;
 220
 221         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 222                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 223         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 224                 return;
 225
 226         if (_tb[SERVICE_TXT])
 227                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 228                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 229
 230         s = calloc_a(sizeof(*s),
 231                 &d_id, strlen(blobmsg_name(b)) + 1,
 232                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 233                 &d_txt, txt_len);
 234         if (!s)
 235                 return;
 236
 237         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 238         s->id = strcpy(d_id, blobmsg_name(b));
 239         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 240         s->active = 1;
 241         s->t = 0;
 242         s->txt_len = txt_len;
 243         s->txt = d_txt;
 244
 245         if (_tb[SERVICE_TXT])
 246                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 247                         int len = strlen(blobmsg_get_string(txt));
 248                         if (!len)
 249                                 return;
 250                         if (len > 0xff)
 251                                 len = 0xff;
 252                         *d_txt = len;
 253                         d_txt++;
 254                         memcpy(d_txt, blobmsg_get_string(txt), len);
 255                         d_txt += len;
 256                 }
 257
 258         vlist_add(&services, &s->node, s->id);
 259 }
 260
 261 static void
 262 service_load(char *path)
 263 {
 264         struct blob_attr *cur;
 265         glob_t gl;
 266         int i, rem;
 267
 268         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 269                 return;
 270
 271         for (i = 0; i < gl.gl_pathc; i++) {
 272                 blob_buf_init(&b, 0);
 273                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 274                         blob_for_each_attr(cur, b.head, rem)
 275                                 service_load_blob(cur);
 276         }
 277         globfree(&gl);
 278 }
 279
 280 static void
 281 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 282 {
 283         struct blob_attr *cur;
 284         int rem;
 285
 286         get_hostname();
 287
 288         vlist_update(&services);
 289         service_load("/tmp/run/mdns/*");
 290
 291         blob_for_each_attr(cur, msg, rem) {
 292                 struct blob_attr *cur2;
 293                 int rem2;
 294
 295                 blobmsg_for_each_attr(cur2, cur, rem2) {
 296                         struct blob_attr *cur3;
 297                         int rem3;
 298
 299                         if (strcmp(blobmsg_name(cur2), "instances"))
 300                                 continue;
 301
 302                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 303                                 struct blob_attr *cur4;
 304                                 int rem4;
 305                                 int running = 0;
 306
 307                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 308                                         const char *name = blobmsg_name(cur4);
 309
 310                                         if (!strcmp(name, "running")) {
 311                                                 running = blobmsg_get_bool(cur4);
 312                                         } else if (running && !strcmp(name, "data")) {
 313                                                 struct blob_attr *cur5;
 314                                                 int rem5;
 315
 316                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 317                                                         struct blob_attr *cur6;
 318                                                         int rem6;
 319
 320                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 321                                                                 continue;
 322
 323                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 324                                                                 service_load_blob(cur6);
 325                                                 }
 326                                                 break;
 327                                         }
 328                                 }
 329                         }
 330                 }
 331         }
 332         vlist_flush(&services);
 333 }
 334
 335 void
 336 service_init(int announce)
 337 {
 338         get_hostname();
 339
 340         service_init_announce = announce;
 341         ubus_service_list(service_init_cb);
 342 }
 343
 344 void
 345 service_cleanup(void)
 346 {
 347         vlist_flush(&services);
 348         blob_buf_free(&b);
 349 }