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 time_t
 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         return t;
 119 }
 120
 121 void
 122 service_reply_a(struct interface *iface, int ttl)
 123 {
 124         struct ifaddrs *ifap, *ifa;
 125         struct sockaddr_in *sa;
 126         struct sockaddr_in6 *sa6;
 127
 128         getifaddrs(&ifap);
 129
 130         dns_init_answer();
 131         for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
 132                 if (strcmp(ifa->ifa_name, iface->name))
 133                         continue;
 134                 if (ifa->ifa_addr->sa_family == AF_INET) {
 135                         sa = (struct sockaddr_in *) ifa->ifa_addr;
 136                         dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
 137                 }
 138                 if (ifa->ifa_addr->sa_family == AF_INET6) {
 139                         uint8_t ll_prefix[] = {0xfe, 0x80 };
 140                         sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
 141                         if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2))
 142                                 dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
 143                 }
 144         }
 145         dns_send_answer(iface, mdns_hostname_local);
 146
 147         freeifaddrs(ifap);
 148 }
 149
 150 static void
 151 service_reply_single(struct interface *iface, struct service *s, const char *match, int ttl, int force)
 152 {
 153         const char *host = service_name(s->service);
 154         char *service = strstr(host, "._");
 155         time_t t = service_timeout(s);
 156
 157
 158         if (!force && (!s->active || !service || !t))
 159                 return;
 160
 161         service++;
 162
 163         if (match && strcmp(match, s->service))
 164                 return;
 165
 166         s->t = t;
 167
 168         dns_init_answer();
 169         service_add_ptr(service_name(s->service), ttl);
 170         dns_send_answer(iface, service);
 171
 172         dns_init_answer();
 173         service_add_srv(s, ttl);
 174         if (s->txt && s->txt_len)
 175                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 176         dns_send_answer(iface, host);
 177 }
 178
 179 void
 180 service_reply(struct interface *iface, const char *match, int ttl)
 181 {
 182         struct service *s;
 183
 184         vlist_for_each_element(&services, s, node)
 185                 service_reply_single(iface, s, match, ttl, 0);
 186
 187         if (match)
 188                 return;
 189
 190         if (ttl)
 191                 service_reply_a(iface, ttl);
 192 }
 193
 194 void
 195 service_announce_services(struct interface *iface, const char *service, int ttl)
 196 {
 197         struct service *s;
 198         int tcp = 1;
 199
 200         if (!strcmp(service, sdudp))
 201                 tcp = 0;
 202         else if (strcmp(service, sdtcp))
 203                 return;
 204
 205         vlist_for_each_element(&services, s, node) {
 206                 if (!strstr(s->service, "._tcp") && tcp)
 207                         continue;
 208                 if (!strstr(s->service, "._udp") && !tcp)
 209                         continue;
 210                 s->t = 0;
 211                 if (ttl) {
 212                         dns_init_answer();
 213                         service_add_ptr(s->service, ttl);
 214                         if (tcp)
 215                                 dns_send_answer(iface, sdtcp);
 216                         else
 217                                 dns_send_answer(iface, sdudp);
 218                 }
 219                 service_reply(iface, s->service, ttl);
 220         }
 221 }
 222
 223 void
 224 service_announce(struct interface *iface, int ttl)
 225 {
 226         service_announce_services(iface, sdudp, ttl);
 227         service_announce_services(iface, sdtcp, ttl);
 228 }
 229
 230 static void
 231 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 232                struct vlist_node *node_old)
 233 {
 234         struct interface *iface;
 235         struct service *s;
 236
 237         if (!node_old) {
 238                 s = container_of(node_new, struct service, node);
 239                 if (service_init_announce)
 240                         vlist_for_each_element(&interfaces, iface, node) {
 241                                 s->t = 0;
 242                                 service_reply_single(iface, s, NULL, announce_ttl, 1);
 243                         }
 244                 return;
 245         }
 246
 247         s = container_of(node_old, struct service, node);
 248         if (!node_new && service_init_announce)
 249                 vlist_for_each_element(&interfaces, iface, node)
 250                         service_reply_single(iface, s, NULL, 0, 1);
 251         free(s);
 252 }
 253
 254 static void
 255 service_load_blob(struct blob_attr *b)
 256 {
 257         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 258         struct service *s;
 259         char *d_service, *d_id;
 260         uint8_t *d_txt;
 261         int rem2;
 262         int txt_len = 0;
 263
 264         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 265                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 266         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 267                 return;
 268
 269         if (_tb[SERVICE_SERVICE])
 270                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 271                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 272
 273         s = calloc_a(sizeof(*s),
 274                 &d_id, strlen(blobmsg_name(b)) + 1,
 275                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 276                 &d_txt, txt_len);
 277         if (!s)
 278                 return;
 279
 280         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 281         s->id = strcpy(d_id, blobmsg_name(b));
 282         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 283         s->active = 1;
 284         s->t = 0;
 285         s->txt_len = txt_len;
 286         s->txt = d_txt;
 287
 288         if (_tb[SERVICE_SERVICE])
 289                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 290                         int len = strlen(blobmsg_get_string(txt));
 291                         if (!len)
 292                                 return;
 293                         if (len > 0xff)
 294                                 len = 0xff;
 295                         *d_txt = len;
 296                         d_txt++;
 297                         memcpy(d_txt, blobmsg_get_string(txt), len);
 298                         d_txt += len;
 299                 }
 300
 301         vlist_add(&services, &s->node, s->id);
 302 }
 303
 304 static void
 305 service_load(char *path)
 306 {
 307         struct blob_attr *cur;
 308         glob_t gl;
 309         int i, rem;
 310
 311         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 312                 return;
 313
 314         for (i = 0; i < gl.gl_pathc; i++) {
 315                 blob_buf_init(&b, 0);
 316                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i]))
 317                         blob_for_each_attr(cur, b.head, rem)
 318                                 service_load_blob(cur);
 319         }
 320         globfree(&gl);
 321 }
 322
 323 static void
 324 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 325 {
 326         struct blob_attr *cur;
 327         int rem;
 328
 329         get_hostname();
 330
 331         vlist_update(&services);
 332         service_load("/tmp/run/mdns/*");
 333
 334         blob_for_each_attr(cur, msg, rem) {
 335                 struct blob_attr *cur2;
 336                 int rem2;
 337
 338                 blobmsg_for_each_attr(cur2, cur, rem2) {
 339                         struct blob_attr *cur3;
 340                         int rem3;
 341
 342                         if (strcmp(blobmsg_name(cur2), "instances"))
 343                                 continue;
 344
 345                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 346                                 struct blob_attr *cur4;
 347                                 int rem4;
 348                                 int running = 0;
 349
 350                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 351                                         const char *name = blobmsg_name(cur4);
 352
 353                                         if (!strcmp(name, "running")) {
 354                                                 running = blobmsg_get_bool(cur4);
 355                                         } else if (running && !strcmp(name, "data")) {
 356                                                 struct blob_attr *cur5;
 357                                                 int rem5;
 358
 359                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 360                                                         struct blob_attr *cur6;
 361                                                         int rem6;
 362
 363                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 364                                                                 continue;
 365
 366                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 367                                                                 service_load_blob(cur6);
 368                                                 }
 369                                                 break;
 370                                         }
 371                                 }
 372                         }
 373                 }
 374         }
 375         vlist_flush(&services);
 376 }
 377
 378 void
 379 service_init(int announce)
 380 {
 381         get_hostname();
 382
 383         service_init_announce = announce;
 384         ubus_service_list(service_init_cb);
 385 }
 386
 387 void
 388 service_cleanup(void)
 389 {
 390         vlist_flush(&services);
 391         blob_buf_free(&b);
 392 }