src/resolve/resolved-dnssd.c

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