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 const char *sdudp =  "_services._dns-sd._udp.local";
  69 static int service_init_announce;
  70
  71 static const char *
  72 service_name(const char *domain)
  73 {
  74         static char buffer[256];
  75
  76         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  77
  78         return buffer;
  79 }
  80
  81 static void
  82 service_add_ptr(const char *host, int ttl)
  83 {
  84         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  85
  86         if (len < 1)
  87                 return;
  88
  89         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
  90 }
  91
  92 static void
  93 service_add_srv(struct service *s, int ttl)
  94 {
  95         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
  96         int len = sizeof(*sd);
  97
  98         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
  99         if (len <= sizeof(*sd))
 100                 return;
 101
 102         sd->port = cpu_to_be16(s->port);
 103         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
 104 }
 105
 106 #define TOUT_LOOKUP     60
 107
 108 static time_t
 109 service_timeout(struct service *s)
 110 {
 111         time_t t = monotonic_time();
 112
 113         if (t - s->t <= TOUT_LOOKUP)
 114                 return 0;
 115
 116         return t;
 117 }
 118
 119 static void
 120 service_reply_single(struct interface *iface, struct sockaddr *to, struct service *s, int ttl, int force)
 121 {
 122         const char *host = service_name(s->service);
 123         char *service = strstr(host, "._");
 124         time_t t = service_timeout(s);
 125
 126
 127         if (!force && (!s->active || !service || !t))
 128                 return;
 129
 130         service++;
 131
 132         s->t = t;
 133
 134         dns_init_answer();
 135         service_add_ptr(service_name(s->service), ttl);
 136         dns_send_answer(iface, to, service);
 137
 138         dns_init_answer();
 139         service_add_srv(s, ttl);
 140         if (s->txt && s->txt_len)
 141                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 142         dns_send_answer(iface, to, host);
 143 }
 144
 145 void
 146 service_reply(struct interface *iface, struct sockaddr *to, const char *match, int ttl)
 147 {
 148         struct service *s;
 149
 150         vlist_for_each_element(&services, s, node) {
 151                 if (!match || !strcmp(s->service, match))
 152                         service_reply_single(iface, to, s, ttl, 0);
 153         }
 154 }
 155
 156 void
 157 service_announce_services(struct interface *iface, struct sockaddr *to, int ttl)
 158 {
 159         struct service *s;
 160
 161         vlist_for_each_element(&services, s, node) {
 162                 s->t = 0;
 163                 if (ttl) {
 164                         dns_init_answer();
 165                         service_add_ptr(s->service, ttl);
 166                         dns_send_answer(iface, to, sdudp);
 167                 }
 168                 service_reply_single(iface, to, s, ttl, 0);
 169         }
 170 }
 171
 172 static void
 173 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 174                struct vlist_node *node_old)
 175 {
 176         struct interface *iface;
 177         struct service *s;
 178
 179         if (!node_old) {
 180                 s = container_of(node_new, struct service, node);
 181                 if (service_init_announce)
 182                         vlist_for_each_element(&interfaces, iface, node) {
 183                                 s->t = 0;
 184                                 service_reply_single(iface, NULL, s, announce_ttl, 1);
 185                         }
 186                 return;
 187         }
 188
 189         s = container_of(node_old, struct service, node);
 190         if (!node_new && service_init_announce)
 191                 vlist_for_each_element(&interfaces, iface, node)
 192                         service_reply_single(iface, NULL, s, 0, 1);
 193         free(s);
 194 }
 195
 196 static void
 197 service_load_blob(struct blob_attr *b)
 198 {
 199         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 200         struct service *s;
 201         char *d_service, *d_id;
 202         uint8_t *d_txt;
 203         int rem2;
 204         int txt_len = 0;
 205
 206         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 207                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 208         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 209                 return;
 210
 211         if (_tb[SERVICE_TXT])
 212                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 213                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 214
 215         s = calloc_a(sizeof(*s),
 216                 &d_id, strlen(blobmsg_name(b)) + 1,
 217                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 218                 &d_txt, txt_len);
 219         if (!s)
 220                 return;
 221
 222         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 223         s->id = strcpy(d_id, blobmsg_name(b));
 224         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 225         s->active = 1;
 226         s->t = 0;
 227         s->txt_len = txt_len;
 228         s->txt = d_txt;
 229
 230         if (_tb[SERVICE_TXT])
 231                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 232                         int len = strlen(blobmsg_get_string(txt));
 233                         if (!len)
 234                                 return;
 235                         if (len > 0xff)
 236                                 len = 0xff;
 237                         *d_txt = len;
 238                         d_txt++;
 239                         memcpy(d_txt, blobmsg_get_string(txt), len);
 240                         d_txt += len;
 241                 }
 242
 243         vlist_add(&services, &s->node, s->id);
 244 }
 245
 246 static void
 247 service_load(char *path)
 248 {
 249         struct blob_attr *cur;
 250         glob_t gl;
 251         int i, rem;
 252
 253         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 254                 return;
 255
 256         for (i = 0; i < gl.gl_pathc; i++) {
 257                 blob_buf_init(&b, 0);
 258                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i])) {
 259                         blob_for_each_attr(cur, b.head, rem)
 260                                 service_load_blob(cur);
 261                 } else {
 262                         fprintf(stderr, "Error reading %s JSON\n", gl.gl_pathv[i]);
 263                 }
 264         }
 265         globfree(&gl);
 266 }
 267
 268 static void
 269 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 270 {
 271         struct blob_attr *cur;
 272         int rem;
 273
 274         get_hostname();
 275
 276         vlist_update(&services);
 277         service_load("/etc/umdns/*");
 278
 279         blob_for_each_attr(cur, msg, rem) {
 280                 struct blob_attr *cur2;
 281                 int rem2;
 282
 283                 blobmsg_for_each_attr(cur2, cur, rem2) {
 284                         struct blob_attr *cur3;
 285                         int rem3;
 286
 287                         if (strcmp(blobmsg_name(cur2), "instances"))
 288                                 continue;
 289
 290                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 291                                 struct blob_attr *cur4;
 292                                 int rem4;
 293                                 int running = 0;
 294
 295                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 296                                         const char *name = blobmsg_name(cur4);
 297
 298                                         if (!strcmp(name, "running")) {
 299                                                 running = blobmsg_get_bool(cur4);
 300                                         } else if (running && !strcmp(name, "data")) {
 301                                                 struct blob_attr *cur5;
 302                                                 int rem5;
 303
 304                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 305                                                         struct blob_attr *cur6;
 306                                                         int rem6;
 307
 308                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 309                                                                 continue;
 310
 311                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 312                                                                 service_load_blob(cur6);
 313                                                 }
 314                                                 break;
 315                                         }
 316                                 }
 317                         }
 318                 }
 319         }
 320         vlist_flush(&services);
 321 }
 322
 323 void
 324 service_init(int announce)
 325 {
 326         get_hostname();
 327
 328         service_init_announce = announce;
 329         ubus_service_list(service_init_cb);
 330 }
 331
 332 void
 333 service_cleanup(void)
 334 {
 335         vlist_flush(&services);
 336         blob_buf_free(&b);
 337 }