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