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 <libubus.h>
  28 #include <libubox/vlist.h>
  29 #include <libubox/uloop.h>
  30 #include <libubox/avl-cmp.h>
  31 #include <libubox/blobmsg_json.h>
  32
  33 #include "ubus.h"
  34 #include "dns.h"
  35 #include "service.h"
  36 #include "util.h"
  37 #include "interface.h"
  38 #include "announce.h"
  39
  40 enum {
  41         SERVICE_SERVICE,
  42         SERVICE_PORT,
  43         SERVICE_TXT,
  44         __SERVICE_MAX,
  45 };
  46
  47 struct service {
  48         struct vlist_node node;
  49
  50         time_t t;
  51
  52         const char *id;
  53         const char *service;
  54         const uint8_t *txt;
  55         int txt_len;
  56         int port;
  57         int active;
  58 };
  59
  60 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
  61         [SERVICE_SERVICE] = { .name = "service", .type = BLOBMSG_TYPE_STRING },
  62         [SERVICE_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT32 },
  63         [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
  64 };
  65
  66 static void
  67 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
  68                struct vlist_node *node_old);
  69
  70 static struct blob_buf b;
  71 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
  72 static char *sdudp =  "_services._dns-sd._udp.local";
  73 static char *sdtcp =  "_services._dns-sd._tcp.local";
  74 static int service_init_announce;
  75
  76 static const char *
  77 service_name(const char *domain)
  78 {
  79         static char buffer[256];
  80
  81         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  82
  83         return buffer;
  84 }
  85
  86 static void
  87 service_add_ptr(const char *host, int ttl)
  88 {
  89         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  90
  91         if (len < 1)
  92                 return;
  93
  94         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
  95 }
  96
  97 static void
  98 service_add_srv(struct service *s, int ttl)
  99 {
 100         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
 101         int len = sizeof(*sd);
 102
 103         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
 104         if (len <= sizeof(*sd))
 105                 return;
 106
 107         sd->port = cpu_to_be16(s->port);
 108         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
 109 }
 110
 111 #define TOUT_LOOKUP     60
 112
 113 static int
 114 service_timeout(struct service *s)
 115 {
 116         time_t t = time(NULL);
 117
 118         if (t - s->t <= TOUT_LOOKUP)
 119                 return 0;
 120
 121         s->t = t;
 122
 123         return 1;
 124 }
 125
 126 void
 127 service_reply_a(struct interface *iface, int ttl)
 128 {
 129         struct ifaddrs *ifap, *ifa;
 130         struct sockaddr_in *sa;
 131         struct sockaddr_in6 *sa6;
 132
 133         getifaddrs(&ifap);
 134
 135         dns_init_answer();
 136         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
 137                 if (strcmp(ifa->ifa_name, iface->name))
 138                         continue;
 139                 if (ifa->ifa_addr->sa_family == AF_INET) {
 140                         sa = (struct sockaddr_in *) ifa->ifa_addr;
 141                         dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
 142                 }
 143                 if (ifa->ifa_addr->sa_family == AF_INET6) {
 144                         uint8_t ll_prefix[] = {0xfe, 0x80 };
 145                         sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
 146                         if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2))
 147                                 dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
 148                 }
 149         }
 150         dns_send_answer(iface, mdns_hostname_local);
 151
 152         freeifaddrs(ifap);
 153 }
 154
 155 static void
 156 service_reply_single(struct interface *iface, struct service *s, const char *match, int ttl, int force)
 157 {
 158         const char *host = service_name(s->service);
 159         char *service = strstr(host, "._");
 160
 161         if (!force && (!s->active || !service || !service_timeout(s)))
 162                 return;
 163
 164         service++;
 165
 166         if (match && strcmp(match, s->service))
 167                 return;
 168
 169         dns_init_answer();
 170         service_add_ptr(service_name(s->service), ttl);
 171         dns_send_answer(iface, service);
 172
 173         dns_init_answer();
 174         service_add_srv(s, ttl);
 175         if (s->txt && s->txt_len)
 176                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 177         dns_send_answer(iface, host);
 178 }
 179
 180 void
 181 service_reply(struct interface *iface, const char *match, int ttl)
 182 {
 183         struct service *s;
 184
 185         vlist_for_each_element(&services, s, node)
 186                 service_reply_single(iface, s, match, ttl, 0);
 187
 188         if (match)
 189                 return;
 190
 191         if (ttl)
 192                 service_reply_a(iface, ttl);
 193 }
 194
 195 void
 196 service_announce_services(struct interface *iface, const char *service, int ttl)
 197 {
 198         struct service *s;
 199         int tcp = 1;
 200
 201         if (!strcmp(service, sdudp))
 202                 tcp = 0;
 203         else if (strcmp(service, sdtcp))
 204                 return;
 205
 206         vlist_for_each_element(&services, s, node) {
 207                 if (!strstr(s->service, "._tcp") && tcp)
 208                         continue;
 209                 if (!strstr(s->service, "._udp") && !tcp)
 210                         continue;
 211                 s->t = 0;
 212                 if (ttl) {
 213                         dns_init_answer();
 214                         service_add_ptr(s->service, ttl);
 215                         if (tcp)
 216                                 dns_send_answer(iface, sdtcp);
 217                         else
 218                                 dns_send_answer(iface, sdudp);
 219                 }
 220                 service_reply(iface, s->service, ttl);
 221         }
 222 }
 223
 224 void
 225 service_announce(struct interface *iface, int ttl)
 226 {
 227         service_announce_services(iface, sdudp, ttl);
 228         service_announce_services(iface, sdtcp, ttl);
 229 }
 230
 231 static void
 232 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 233                struct vlist_node *node_old)
 234 {
 235         struct interface *iface;
 236         struct service *s;
 237
 238         if (!node_old) {
 239                 s = container_of(node_new, struct service, node);
 240                 if (service_init_announce)
 241                         vlist_for_each_element(&interfaces, iface, node) {
 242                                 s->t = 0;
 243                                 service_reply_single(iface, s, NULL, announce_ttl, 1);
 244                         }
 245                 return;
 246         }
 247
 248         s = container_of(node_old, struct service, node);
 249         if (!node_new && service_init_announce)
 250                 vlist_for_each_element(&interfaces, iface, node)
 251                         service_reply_single(iface, s, NULL, 0, 1);
 252         free(s);
 253 }
 254
 255 static void
 256 service_load_blob(struct blob_attr *b)
 257 {
 258         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 259         struct service *s;
 260         char *d_service, *d_id;
 261         uint8_t *d_txt;
 262         int rem2;
 263         int txt_len = 0;
 264
 265         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 266                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 267         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 268                 return;
 269
 270         if (_tb[SERVICE_SERVICE])
 271                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 272                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 273
 274         s = calloc_a(sizeof(*s),
 275                 &d_id, strlen(blobmsg_name(b)) + 1,
 276                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 277                 &d_txt, txt_len);
 278         if (!s)
 279                 return;
 280
 281         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 282         s->id = strcpy(d_id, blobmsg_name(b));
 283         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 284         s->active = 1;
 285         s->t = 0;
 286         s->txt_len = txt_len;
 287         s->txt = d_txt;
 288
 289         if (_tb[SERVICE_SERVICE])
 290                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 291                         int len = strlen(blobmsg_get_string(txt));
 292                         if (!len)
 293                                 return;
 294                         if (len > 0xff)
 295                                 len = 0xff;
 296                         *d_txt = len;
 297                         d_txt++;
 298                         memcpy(d_txt, blobmsg_get_string(txt), len);
 299                         d_txt += len;
 300                 }
 301
 302         vlist_add(&services, &s->node, s->id);
 303 }
 304
 305 static void
 306 service_load(char *path)
 307 {
 308         struct blob_attr *cur;
 309         glob_t gl;
 310         int i, rem;
 311
 312         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 313                 return;
 314
 315         for (i = 0; i < gl.gl_pathc; i++) {
 316                 blob_buf_init(&b, 0);
 317                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 318                         blob_for_each_attr(cur, b.head, rem)
 319                                 service_load_blob(cur);
 320         }
 321         globfree(&gl);
 322 }
 323
 324 static void
 325 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 326 {
 327         struct blob_attr *cur;
 328         int rem;
 329
 330         get_hostname();
 331
 332         vlist_update(&services);
 333         service_load("/tmp/run/mdns/*");
 334
 335         blob_for_each_attr(cur, msg, rem) {
 336                 struct blob_attr *cur2;
 337                 int rem2;
 338
 339                 blobmsg_for_each_attr(cur2, cur, rem2) {
 340                         struct blob_attr *cur3;
 341                         int rem3;
 342
 343                         if (strcmp(blobmsg_name(cur2), "instances"))
 344                                 continue;
 345
 346                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 347                                 struct blob_attr *cur4;
 348                                 int rem4;
 349                                 int running = 0;
 350
 351                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 352                                         const char *name = blobmsg_name(cur4);
 353
 354                                         if (!strcmp(name, "running")) {
 355                                                 running = blobmsg_get_bool(cur4);
 356                                         } else if (running && !strcmp(name, "data")) {
 357                                                 struct blob_attr *cur5;
 358                                                 int rem5;
 359
 360                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 361                                                         struct blob_attr *cur6;
 362                                                         int rem6;
 363
 364                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 365                                                                 continue;
 366
 367                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 368                                                                 service_load_blob(cur6);
 369                                                 }
 370                                                 break;
 371                                         }
 372                                 }
 373                         }
 374                 }
 375         }
 376         vlist_flush(&services);
 377 }
 378
 379 void
 380 service_init(int announce)
 381 {
 382         get_hostname();
 383
 384         service_init_announce = announce;
 385         ubus_service_list(service_init_cb);
 386 }
 387
 388 void
 389 service_cleanup(void)
 390 {
 391         vlist_flush(&services);
 392         blob_buf_free(&b);
 393 }