src/resolve/resolved-dnssd.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "conf-files.h"
   4 #include "conf-parser.h"
   5 #include "def.h"
   6 #include "resolved-dnssd.h"
   7 #include "resolved-dns-rr.h"
   8 #include "resolved-manager.h"
   9 #include "resolved-conf.h"
  10 #include "specifier.h"
  11 #include "strv.h"
  12
  13 #define DNSSD_SERVICE_DIRS ((const char* const*) CONF_PATHS_STRV("systemd/dnssd"))
  14
  15 DnssdTxtData *dnssd_txtdata_free(DnssdTxtData *txt_data) {
  16         if (!txt_data)
  17                 return NULL;
  18
  19         dns_resource_record_unref(txt_data->rr);
  20         dns_txt_item_free_all(txt_data->txt);
  21
  22         return mfree(txt_data);
  23 }
  24
  25 DnssdTxtData *dnssd_txtdata_free_all(DnssdTxtData *txt_data) {
  26         DnssdTxtData *next;
  27
  28         if (!txt_data)
  29                 return NULL;
  30
  31         next = txt_data->items_next;
  32
  33         dnssd_txtdata_free(txt_data);
  34
  35         return dnssd_txtdata_free_all(next);
  36 }
  37
  38 DnssdService *dnssd_service_free(DnssdService *service) {
  39         if (!service)
  40                 return NULL;
  41
  42         if (service->manager)
  43                 hashmap_remove(service->manager->dnssd_services, service->name);
  44
  45         dns_resource_record_unref(service->ptr_rr);
  46         dns_resource_record_unref(service->srv_rr);
  47
  48         dnssd_txtdata_free_all(service->txt_data_items);
  49
  50         free(service->filename);
  51         free(service->name);
  52         free(service->type);
  53         free(service->name_template);
  54
  55         return mfree(service);
  56 }
  57
  58 static int dnssd_service_load(Manager *manager, const char *filename) {
  59         _cleanup_(dnssd_service_freep) DnssdService *service = NULL;
  60         _cleanup_(dnssd_txtdata_freep) DnssdTxtData *txt_data = NULL;
  61         char *d;
  62         const char *dropin_dirname;
  63         int r;
  64
  65         assert(manager);
  66         assert(filename);
  67
  68         service = new0(DnssdService, 1);
  69         if (!service)
  70                 return log_oom();
  71
  72         service->filename = strdup(filename);
  73         if (!service->filename)
  74                 return log_oom();
  75
  76         service->name = strdup(basename(filename));
  77         if (!service->name)
  78                 return log_oom();
  79
  80         d = endswith(service->name, ".dnssd");
  81         if (!d)
  82                 return -EINVAL;
  83
  84         assert(streq(d, ".dnssd"));
  85
  86         *d = '\0';
  87
  88         dropin_dirname = strjoina(service->name, ".dnssd.d");
  89
  90         r = config_parse_many(
  91                         filename, DNSSD_SERVICE_DIRS, dropin_dirname,
  92                         "Service\0",
  93                         config_item_perf_lookup, resolved_dnssd_gperf_lookup,
  94                         CONFIG_PARSE_WARN,
  95                         service,
  96                         NULL);
  97         if (r < 0)
  98                 return r;
  99
 100         if (!service->name_template)
 101                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 102                                        "%s doesn't define service instance name",
 103                                        service->name);
 104
 105         if (!service->type)
 106                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 107                                        "%s doesn't define service type",
 108                                        service->name);
 109
 110         if (LIST_IS_EMPTY(service->txt_data_items)) {
 111                 txt_data = new0(DnssdTxtData, 1);
 112                 if (!txt_data)
 113                         return log_oom();
 114
 115                 r = dns_txt_item_new_empty(&txt_data->txt);
 116                 if (r < 0)
 117                         return r;
 118
 119                 LIST_PREPEND(items, service->txt_data_items, txt_data);
 120                 txt_data = NULL;
 121         }
 122
 123         r = hashmap_ensure_allocated(&manager->dnssd_services, &string_hash_ops);
 124         if (r < 0)
 125                 return r;
 126
 127         r = hashmap_put(manager->dnssd_services, service->name, service);
 128         if (r < 0)
 129                 return r;
 130
 131         service->manager = manager;
 132
 133         r = dnssd_update_rrs(service);
 134         if (r < 0)
 135                 return r;
 136
 137         service = NULL;
 138
 139         return 0;
 140 }
 141
 142 static int specifier_dnssd_host_name(char specifier, const void *data, const void *userdata, char **ret) {
 143         DnssdService *s  = (DnssdService *) userdata;
 144         char *n;
 145
 146         assert(s);
 147         assert(s->manager);
 148         assert(s->manager->llmnr_hostname);
 149
 150         n = strdup(s->manager->llmnr_hostname);
 151         if (!n)
 152                 return -ENOMEM;
 153
 154         *ret = n;
 155         return 0;
 156 }
 157
 158 int dnssd_render_instance_name(const char *name_template, char **ret_name) {
 159         static const Specifier specifier_table[] = {
 160                 { 'm', specifier_machine_id,      NULL },
 161                 { 'b', specifier_boot_id,         NULL },
 162                 { 'H', specifier_dnssd_host_name, NULL },
 163                 { 'v', specifier_kernel_release,  NULL },
 164                 { 'a', specifier_architecture,    NULL },
 165                 { 'o', specifier_os_id,           NULL },
 166                 { 'w', specifier_os_version_id,   NULL },
 167                 { 'B', specifier_os_build_id,     NULL },
 168                 { 'W', specifier_os_variant_id,   NULL },
 169                 {}
 170         };
 171         _cleanup_free_ char *name = NULL;
 172         int r;
 173
 174         assert(name_template);
 175
 176         r = specifier_printf(name_template, specifier_table, NULL, &name);
 177         if (r < 0)
 178                 return r;
 179
 180         if (!dns_service_name_is_valid(name))
 181                 return -EINVAL;
 182
 183         if (ret_name)
 184                 *ret_name = TAKE_PTR(name);
 185
 186         return 0;
 187 }
 188
 189 int dnssd_load(Manager *manager) {
 190         _cleanup_strv_free_ char **files = NULL;
 191         char **f;
 192         int r;
 193
 194         assert(manager);
 195
 196         if (manager->mdns_support != RESOLVE_SUPPORT_YES)
 197                 return 0;
 198
 199         r = conf_files_list_strv(&files, ".dnssd", NULL, 0, DNSSD_SERVICE_DIRS);
 200         if (r < 0)
 201                 return log_error_errno(r, "Failed to enumerate .dnssd files: %m");
 202
 203         STRV_FOREACH_BACKWARDS(f, files) {
 204                 r = dnssd_service_load(manager, *f);
 205                 if (r < 0)
 206                         log_warning_errno(r, "Failed to load '%s': %m", *f);;
 207         }
 208
 209         return 0;
 210 }
 211
 212 int dnssd_update_rrs(DnssdService *s) {
 213         _cleanup_free_ char *n = NULL;
 214         _cleanup_free_ char *service_name = NULL;
 215         _cleanup_free_ char *full_name = NULL;
 216         DnssdTxtData *txt_data;
 217         int r;
 218
 219         assert(s);
 220         assert(s->txt_data_items);
 221         assert(s->manager);
 222
 223         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 224         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 225         LIST_FOREACH(items, txt_data, s->txt_data_items)
 226                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 227
 228         r = dnssd_render_instance_name(s->name_template, &n);
 229         if (r < 0)
 230                 return r;
 231
 232         r = dns_name_concat(s->type, "local", 0, &service_name);
 233         if (r < 0)
 234                 return r;
 235         r = dns_name_concat(n, service_name, 0, &full_name);
 236         if (r < 0)
 237                 return r;
 238
 239         LIST_FOREACH(items, txt_data, s->txt_data_items) {
 240                 txt_data->rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_TXT,
 241                                                             full_name);
 242                 if (!txt_data->rr)
 243                         goto oom;
 244
 245                 txt_data->rr->ttl = MDNS_DEFAULT_TTL;
 246                 txt_data->rr->txt.items = dns_txt_item_copy(txt_data->txt);
 247                 if (!txt_data->rr->txt.items)
 248                         goto oom;
 249         }
 250
 251         s->ptr_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
 252                                                  service_name);
 253         if (!s->ptr_rr)
 254                 goto oom;
 255
 256         s->ptr_rr->ttl = MDNS_DEFAULT_TTL;
 257         s->ptr_rr->ptr.name = strdup(full_name);
 258         if (!s->ptr_rr->ptr.name)
 259                 goto oom;
 260
 261         s->srv_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SRV,
 262                                                  full_name);
 263         if (!s->srv_rr)
 264                 goto oom;
 265
 266         s->srv_rr->ttl = MDNS_DEFAULT_TTL;
 267         s->srv_rr->srv.priority = s->priority;
 268         s->srv_rr->srv.weight = s->weight;
 269         s->srv_rr->srv.port = s->port;
 270         s->srv_rr->srv.name = strdup(s->manager->mdns_hostname);
 271         if (!s->srv_rr->srv.name)
 272                 goto oom;
 273
 274         return 0;
 275
 276 oom:
 277         LIST_FOREACH(items, txt_data, s->txt_data_items)
 278                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 279         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 280         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 281         return -ENOMEM;
 282 }
 283
 284 int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item) {
 285         size_t length;
 286         DnsTxtItem *i;
 287
 288         length = strlen(key);
 289
 290         if (!isempty(value))
 291                 length += strlen(value) + 1; /* length of value plus '=' */
 292
 293         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 294         if (!i)
 295                 return -ENOMEM;
 296
 297         memcpy(i->data, key, strlen(key));
 298         if (!isempty(value)) {
 299                 memcpy(i->data + strlen(key), "=", 1);
 300                 memcpy(i->data + strlen(key) + 1, value, strlen(value));
 301         }
 302         i->length = length;
 303
 304         *ret_item = TAKE_PTR(i);
 305
 306         return 0;
 307 }
 308
 309 int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t size, DnsTxtItem **ret_item) {
 310         size_t length;
 311         DnsTxtItem *i;
 312
 313         length = strlen(key);
 314
 315         if (size > 0)
 316                 length += size + 1; /* size of date plus '=' */
 317
 318         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 319         if (!i)
 320                 return -ENOMEM;
 321
 322         memcpy(i->data, key, strlen(key));
 323         if (size > 0) {
 324                 memcpy(i->data + strlen(key), "=", 1);
 325                 memcpy(i->data + strlen(key) + 1, data, size);
 326         }
 327         i->length = length;
 328
 329         *ret_item = TAKE_PTR(i);
 330
 331         return 0;
 332 }
 333
 334 void dnssd_signal_conflict(Manager *manager, const char *name) {
 335         DnssdService *s;
 336         int r;
 337
 338         HASHMAP_FOREACH(s, manager->dnssd_services) {
 339                 if (s->withdrawn)
 340                         continue;
 341
 342                 if (dns_name_equal(dns_resource_key_name(s->srv_rr->key), name)) {
 343                         _cleanup_free_ char *path = NULL;
 344
 345                         s->withdrawn = true;
 346
 347                         r = sd_bus_path_encode("/org/freedesktop/resolve1/dnssd", s->name, &path);
 348                         if (r < 0) {
 349                                 log_error_errno(r, "Can't get D-BUS object path: %m");
 350                                 return;
 351                         }
 352
 353                         r = sd_bus_emit_signal(manager->bus,
 354                                                path,
 355                                                "org.freedesktop.resolve1.DnssdService",
 356                                                "Conflicted",
 357                                                NULL);
 358                         if (r < 0) {
 359                                 log_error_errno(r, "Cannot emit signal: %m");
 360                                 return;
 361                         }
 362
 363                         break;
 364                 }
 365         }
 366 }