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                         STRV_MAKE_CONST(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 (!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                 TAKE_PTR(txt_data);
 121         }
 122
 123         r = hashmap_ensure_put(&manager->dnssd_services, &string_hash_ops, service->name, service);
 124         if (r < 0)
 125                 return r;
 126
 127         service->manager = manager;
 128
 129         r = dnssd_update_rrs(service);
 130         if (r < 0)
 131                 return r;
 132
 133         TAKE_PTR(service);
 134
 135         return 0;
 136 }
 137
 138 static int specifier_dnssd_hostname(char specifier, const void *data, const char *root, const void *userdata, char **ret) {
 139         const Manager *m = ASSERT_PTR(userdata);
 140         char *n;
 141
 142         assert(m->llmnr_hostname);
 143
 144         n = strdup(m->llmnr_hostname);
 145         if (!n)
 146                 return -ENOMEM;
 147
 148         *ret = n;
 149         return 0;
 150 }
 151
 152 int dnssd_render_instance_name(Manager *m, DnssdService *s, char **ret) {
 153         static const Specifier specifier_table[] = {
 154                 { 'a', specifier_architecture,   NULL },
 155                 { 'b', specifier_boot_id,        NULL },
 156                 { 'B', specifier_os_build_id,    NULL },
 157                 { 'H', specifier_dnssd_hostname, NULL },
 158                 { 'm', specifier_machine_id,     NULL },
 159                 { 'o', specifier_os_id,          NULL },
 160                 { 'v', specifier_kernel_release, NULL },
 161                 { 'w', specifier_os_version_id,  NULL },
 162                 { 'W', specifier_os_variant_id,  NULL },
 163                 {}
 164         };
 165         _cleanup_free_ char *name = NULL;
 166         int r;
 167
 168         assert(m);
 169         assert(s);
 170         assert(s->name_template);
 171
 172         r = specifier_printf(s->name_template, DNS_LABEL_MAX, specifier_table, NULL, m, &name);
 173         if (r < 0)
 174                 return log_debug_errno(r, "Failed to replace specifiers: %m");
 175
 176         if (!dns_service_name_is_valid(name))
 177                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
 178                                        "Service instance name '%s' is invalid.",
 179                                        name);
 180
 181         if (ret)
 182                 *ret = TAKE_PTR(name);
 183
 184         return 0;
 185 }
 186
 187 int dnssd_load(Manager *manager) {
 188         _cleanup_strv_free_ char **files = NULL;
 189         int r;
 190
 191         assert(manager);
 192
 193         if (manager->mdns_support != RESOLVE_SUPPORT_YES)
 194                 return 0;
 195
 196         r = conf_files_list_strv(&files, ".dnssd", NULL, 0, DNSSD_SERVICE_DIRS);
 197         if (r < 0)
 198                 return log_error_errno(r, "Failed to enumerate .dnssd files: %m");
 199
 200         STRV_FOREACH_BACKWARDS(f, files) {
 201                 r = dnssd_service_load(manager, *f);
 202                 if (r < 0)
 203                         log_warning_errno(r, "Failed to load '%s': %m", *f);;
 204         }
 205
 206         return 0;
 207 }
 208
 209 int dnssd_update_rrs(DnssdService *s) {
 210         _cleanup_free_ char *n = NULL, *service_name = NULL, *full_name = NULL;
 211         int r;
 212
 213         assert(s);
 214         assert(s->txt_data_items);
 215         assert(s->manager);
 216
 217         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 218         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 219         LIST_FOREACH(items, txt_data, s->txt_data_items)
 220                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 221
 222         r = dnssd_render_instance_name(s->manager, s, &n);
 223         if (r < 0)
 224                 return r;
 225
 226         r = dns_name_concat(s->type, "local", 0, &service_name);
 227         if (r < 0)
 228                 return r;
 229         r = dns_name_concat(n, service_name, 0, &full_name);
 230         if (r < 0)
 231                 return r;
 232
 233         LIST_FOREACH(items, txt_data, s->txt_data_items) {
 234                 txt_data->rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_TXT,
 235                                                             full_name);
 236                 if (!txt_data->rr)
 237                         goto oom;
 238
 239                 txt_data->rr->ttl = MDNS_DEFAULT_TTL;
 240                 txt_data->rr->txt.items = dns_txt_item_copy(txt_data->txt);
 241                 if (!txt_data->rr->txt.items)
 242                         goto oom;
 243         }
 244
 245         s->ptr_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
 246                                                  service_name);
 247         if (!s->ptr_rr)
 248                 goto oom;
 249
 250         s->ptr_rr->ttl = MDNS_DEFAULT_TTL;
 251         s->ptr_rr->ptr.name = strdup(full_name);
 252         if (!s->ptr_rr->ptr.name)
 253                 goto oom;
 254
 255         s->srv_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SRV,
 256                                                  full_name);
 257         if (!s->srv_rr)
 258                 goto oom;
 259
 260         s->srv_rr->ttl = MDNS_DEFAULT_TTL;
 261         s->srv_rr->srv.priority = s->priority;
 262         s->srv_rr->srv.weight = s->weight;
 263         s->srv_rr->srv.port = s->port;
 264         s->srv_rr->srv.name = strdup(s->manager->mdns_hostname);
 265         if (!s->srv_rr->srv.name)
 266                 goto oom;
 267
 268         return 0;
 269
 270 oom:
 271         LIST_FOREACH(items, txt_data, s->txt_data_items)
 272                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 273         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 274         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 275         return -ENOMEM;
 276 }
 277
 278 int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item) {
 279         size_t length;
 280         DnsTxtItem *i;
 281
 282         length = strlen(key);
 283
 284         if (!isempty(value))
 285                 length += strlen(value) + 1; /* length of value plus '=' */
 286
 287         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 288         if (!i)
 289                 return -ENOMEM;
 290
 291         memcpy(i->data, key, strlen(key));
 292         if (!isempty(value)) {
 293                 memcpy(i->data + strlen(key), "=", 1);
 294                 memcpy(i->data + strlen(key) + 1, value, strlen(value));
 295         }
 296         i->length = length;
 297
 298         *ret_item = TAKE_PTR(i);
 299
 300         return 0;
 301 }
 302
 303 int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t size, DnsTxtItem **ret_item) {
 304         size_t length;
 305         DnsTxtItem *i;
 306
 307         length = strlen(key);
 308
 309         if (size > 0)
 310                 length += size + 1; /* size of date plus '=' */
 311
 312         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 313         if (!i)
 314                 return -ENOMEM;
 315
 316         memcpy(i->data, key, strlen(key));
 317         if (size > 0) {
 318                 memcpy(i->data + strlen(key), "=", 1);
 319                 memcpy(i->data + strlen(key) + 1, data, size);
 320         }
 321         i->length = length;
 322
 323         *ret_item = TAKE_PTR(i);
 324
 325         return 0;
 326 }
 327
 328 int dnssd_signal_conflict(Manager *manager, const char *name) {
 329         DnssdService *s;
 330         int r;
 331
 332         if (sd_bus_is_ready(manager->bus) <= 0)
 333                 return 0;
 334
 335         HASHMAP_FOREACH(s, manager->dnssd_services) {
 336                 if (s->withdrawn)
 337                         continue;
 338
 339                 if (dns_name_equal(dns_resource_key_name(s->srv_rr->key), name)) {
 340                         _cleanup_free_ char *path = NULL;
 341
 342                         s->withdrawn = true;
 343
 344                         r = sd_bus_path_encode("/org/freedesktop/resolve1/dnssd", s->name, &path);
 345                         if (r < 0)
 346                                 return log_error_errno(r, "Can't get D-BUS object path: %m");
 347
 348                         r = sd_bus_emit_signal(manager->bus,
 349                                                path,
 350                                                "org.freedesktop.resolve1.DnssdService",
 351                                                "Conflicted",
 352                                                NULL);
 353                         if (r < 0)
 354                                 return log_error_errno(r, "Cannot emit signal: %m");
 355
 356                         break;
 357                 }
 358         }
 359
 360         return 0;
 361 }