src/resolve/resolved-dnssd.c

   1 /***
   2   Copyright 2017 Dmitry Rozhkov
   3 ***/
   4
   5 #include "conf-files.h"
   6 #include "conf-parser.h"
   7 #include "resolved-dnssd.h"
   8 #include "resolved-dns-rr.h"
   9 #include "resolved-manager.h"
  10 #include "specifier.h"
  11 #include "strv.h"
  12
  13 const char* const dnssd_service_dirs[] = {
  14         "/etc/systemd/dnssd",
  15         "/run/systemd/dnssd",
  16         "/usr/lib/systemd/dnssd",
  17 #ifdef HAVE_SPLIT_USR
  18         "/lib/systemd/dnssd",
  19 #endif
  20     NULL
  21 };
  22
  23 DnssdTxtData *dnssd_txtdata_free(DnssdTxtData *txt_data) {
  24         if (!txt_data)
  25                 return NULL;
  26
  27         dns_resource_record_unref(txt_data->rr);
  28         dns_txt_item_free_all(txt_data->txt);
  29
  30         return mfree(txt_data);
  31 }
  32
  33 DnssdTxtData *dnssd_txtdata_free_all(DnssdTxtData *txt_data) {
  34         DnssdTxtData *next;
  35
  36         if (!txt_data)
  37                 return NULL;
  38
  39         next = txt_data->items_next;
  40
  41         dnssd_txtdata_free(txt_data);
  42
  43         return dnssd_txtdata_free_all(next);
  44 }
  45
  46 DnssdService *dnssd_service_free(DnssdService *service) {
  47         if (!service)
  48                 return NULL;
  49
  50         if (service->manager)
  51                 hashmap_remove(service->manager->dnssd_services, service->name);
  52
  53         dns_resource_record_unref(service->ptr_rr);
  54         dns_resource_record_unref(service->srv_rr);
  55
  56         dnssd_txtdata_free_all(service->txt_data_items);
  57
  58         free(service->filename);
  59         free(service->name);
  60         free(service->type);
  61         free(service->name_template);
  62
  63         return mfree(service);
  64 }
  65
  66 static int dnssd_service_load(Manager *manager, const char *filename) {
  67         _cleanup_(dnssd_service_freep) DnssdService *service = NULL;
  68         _cleanup_(dnssd_txtdata_freep) DnssdTxtData *txt_data = NULL;
  69         char *d;
  70         const char *dropin_dirname;
  71         int r;
  72
  73         assert(manager);
  74         assert(filename);
  75
  76         service = new0(DnssdService, 1);
  77         if (!service)
  78                 return log_oom();
  79
  80         service->filename = strdup(filename);
  81         if (!service->filename)
  82                 return log_oom();
  83
  84         service->name = strdup(basename(filename));
  85         if (!service->name)
  86                 return log_oom();
  87
  88         d = endswith(service->name, ".dnssd");
  89         if (!d)
  90                 return -EINVAL;
  91
  92         assert(streq(d, ".dnssd"));
  93
  94         *d = '\0';
  95
  96         dropin_dirname = strjoina(service->name, ".dnssd.d");
  97
  98         r = config_parse_many(filename, dnssd_service_dirs, dropin_dirname,
  99                               "Service\0",
 100                               config_item_perf_lookup, resolved_dnssd_gperf_lookup,
 101                               false, service);
 102         if (r < 0)
 103                 return r;
 104
 105         if (!service->name_template) {
 106                 log_error("%s doesn't define service instance name", service->name);
 107                 return -EINVAL;
 108         }
 109
 110         if (!service->type) {
 111                 log_error("%s doesn't define service type", service->name);
 112                 return -EINVAL;
 113         }
 114
 115         if (LIST_IS_EMPTY(service->txt_data_items)) {
 116                 txt_data = new0(DnssdTxtData, 1);
 117                 if (!txt_data)
 118                         return log_oom();
 119
 120                 r = dns_txt_item_new_empty(&txt_data->txt);
 121                 if (r < 0)
 122                         return r;
 123
 124                 LIST_PREPEND(items, service->txt_data_items, txt_data);
 125                 txt_data = NULL;
 126         }
 127
 128         r = hashmap_ensure_allocated(&manager->dnssd_services, &string_hash_ops);
 129         if (r < 0)
 130                 return r;
 131
 132         r = hashmap_put(manager->dnssd_services, service->name, service);
 133         if (r < 0)
 134                 return r;
 135
 136         service->manager = manager;
 137
 138         r = dnssd_update_rrs(service);
 139         if (r < 0)
 140                 return r;
 141
 142         service = NULL;
 143
 144         return 0;
 145 }
 146
 147 static int specifier_dnssd_host_name(char specifier, void *data, void *userdata, char **ret) {
 148         DnssdService *s  = (DnssdService *) userdata;
 149         char *n;
 150
 151         assert(s);
 152         assert(s->manager);
 153         assert(s->manager->llmnr_hostname);
 154
 155         n = strdup(s->manager->llmnr_hostname);
 156         if (!n)
 157                 return -ENOMEM;
 158
 159         *ret = n;
 160         return 0;
 161 }
 162
 163 int dnssd_render_instance_name(DnssdService *s, char **ret_name) {
 164         static const Specifier specifier_table[] = {
 165                 { 'b', specifier_boot_id,         NULL },
 166                 { 'H', specifier_dnssd_host_name, NULL },
 167                 { 'm', specifier_machine_id,      NULL },
 168                 { 'v', specifier_kernel_release,  NULL },
 169                 {}
 170         };
 171         _cleanup_free_ char *name = NULL;
 172         int r;
 173
 174         assert(s);
 175         assert(s->name_template);
 176
 177         r = specifier_printf(s->name_template, specifier_table, s, &name);
 178         if (r < 0)
 179                 return log_debug_errno(r, "Failed to replace specifiers: %m");
 180
 181         if (!dns_service_name_is_valid(name)) {
 182                 log_debug("Service instance name '%s' is invalid.", name);
 183                 return -EINVAL;
 184         }
 185
 186         *ret_name = TAKE_PTR(name);
 187
 188         return 0;
 189 }
 190
 191 int dnssd_load(Manager *manager) {
 192         _cleanup_strv_free_ char **files = NULL;
 193         char **f;
 194         int r;
 195
 196         assert(manager);
 197
 198         if (manager->mdns_support != RESOLVE_SUPPORT_YES)
 199                 return 0;
 200
 201         r = conf_files_list_strv(&files, ".dnssd", NULL, 0, dnssd_service_dirs);
 202         if (r < 0)
 203                 return log_error_errno(r, "Failed to enumerate .dnssd files: %m");
 204
 205         STRV_FOREACH_BACKWARDS(f, files) {
 206                 r = dnssd_service_load(manager, *f);
 207                 if (r < 0)
 208                         log_warning_errno(r, "Failed to load '%s': %m", *f);;
 209         }
 210
 211         return 0;
 212 }
 213
 214 int dnssd_update_rrs(DnssdService *s) {
 215         _cleanup_free_ char *n = NULL;
 216         _cleanup_free_ char *service_name = NULL;
 217         _cleanup_free_ char *full_name = NULL;
 218         DnssdTxtData *txt_data;
 219         int r;
 220
 221         assert(s);
 222         assert(s->txt_data_items);
 223         assert(s->manager);
 224
 225         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 226         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 227         LIST_FOREACH(items, txt_data, s->txt_data_items)
 228                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 229
 230         r = dnssd_render_instance_name(s, &n);
 231         if (r < 0)
 232                 return r;
 233
 234         r = dns_name_concat(s->type, "local", &service_name);
 235         if (r < 0)
 236                 return r;
 237         r = dns_name_concat(n, service_name, &full_name);
 238         if (r < 0)
 239                 return r;
 240
 241         LIST_FOREACH(items, txt_data, s->txt_data_items) {
 242                 txt_data->rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_TXT,
 243                                                             full_name);
 244                 if (!txt_data->rr)
 245                         goto oom;
 246
 247                 txt_data->rr->ttl = MDNS_DEFAULT_TTL;
 248                 txt_data->rr->txt.items = dns_txt_item_copy(txt_data->txt);
 249                 if (!txt_data->rr->txt.items)
 250                         goto oom;
 251         }
 252
 253         s->ptr_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
 254                                                  service_name);
 255         if (!s->ptr_rr)
 256                 goto oom;
 257
 258         s->ptr_rr->ttl = MDNS_DEFAULT_TTL;
 259         s->ptr_rr->ptr.name = strdup(full_name);
 260         if (!s->ptr_rr->ptr.name)
 261                 goto oom;
 262
 263         s->srv_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SRV,
 264                                                  full_name);
 265         if (!s->srv_rr)
 266                 goto oom;
 267
 268         s->srv_rr->ttl = MDNS_DEFAULT_TTL;
 269         s->srv_rr->srv.priority = s->priority;
 270         s->srv_rr->srv.weight = s->weight;
 271         s->srv_rr->srv.port = s->port;
 272         s->srv_rr->srv.name = strdup(s->manager->mdns_hostname);
 273         if (!s->srv_rr->srv.name)
 274                 goto oom;
 275
 276         return 0;
 277
 278 oom:
 279         LIST_FOREACH(items, txt_data, s->txt_data_items)
 280                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 281         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 282         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 283         return -ENOMEM;
 284 }
 285
 286 int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item) {
 287         size_t length;
 288         DnsTxtItem *i;
 289
 290         length = strlen(key);
 291
 292         if (!isempty(value))
 293                 length += strlen(value) + 1; /* length of value plus '=' */
 294
 295         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 296         if (!i)
 297                 return -ENOMEM;
 298
 299         memcpy(i->data, key, strlen(key));
 300         if (!isempty(value)) {
 301                 memcpy(i->data + strlen(key), "=", 1);
 302                 memcpy(i->data + strlen(key) + 1, value, strlen(value));
 303         }
 304         i->length = length;
 305
 306         *ret_item = TAKE_PTR(i);
 307
 308         return 0;
 309 }
 310
 311 int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t size, DnsTxtItem **ret_item) {
 312         size_t length;
 313         DnsTxtItem *i;
 314
 315         length = strlen(key);
 316
 317         if (size > 0)
 318                 length += size + 1; /* size of date plus '=' */
 319
 320         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 321         if (!i)
 322                 return -ENOMEM;
 323
 324         memcpy(i->data, key, strlen(key));
 325         if (size > 0) {
 326                 memcpy(i->data + strlen(key), "=", 1);
 327                 memcpy(i->data + strlen(key) + 1, data, size);
 328         }
 329         i->length = length;
 330
 331         *ret_item = TAKE_PTR(i);
 332
 333         return 0;
 334 }
 335
 336 void dnssd_signal_conflict(Manager *manager, const char *name) {
 337         Iterator i;
 338         DnssdService *s;
 339         int r;
 340
 341         HASHMAP_FOREACH(s, manager->dnssd_services, i) {
 342                 if (s->withdrawn)
 343                         continue;
 344
 345                 if (dns_name_equal(dns_resource_key_name(s->srv_rr->key), name)) {
 346                         _cleanup_free_ char *path = NULL;
 347
 348                         s->withdrawn = true;
 349
 350                         r = sd_bus_path_encode("/org/freedesktop/resolve1/dnssd", s->name, &path);
 351                         if (r < 0) {
 352                                 log_error_errno(r, "Can't get D-BUS object path: %m");
 353                                 return;
 354                         }
 355
 356                         r = sd_bus_emit_signal(manager->bus,
 357                                                path,
 358                                                "org.freedesktop.resolve1.DnssdService",
 359                                                "Conflicted",
 360                                                NULL);
 361                         if (r < 0) {
 362                                 log_error_errno(r, "Cannot emit signal: %m");
 363                                 return;
 364                         }
 365
 366                         break;
 367                 }
 368         }
 369 }