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 (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                 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_host_name(char specifier, const void *data, const char *root, 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                 { 'a', specifier_architecture,    NULL },
 157                 { 'b', specifier_boot_id,         NULL },
 158                 { 'B', specifier_os_build_id,     NULL },
 159                 { 'H', specifier_dnssd_host_name, NULL },
 160                 { 'm', specifier_machine_id,      NULL },
 161                 { 'o', specifier_os_id,           NULL },
 162                 { 'v', specifier_kernel_release,  NULL },
 163                 { 'w', specifier_os_version_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, DNS_LABEL_MAX, specifier_table, NULL, 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         int r;
 215
 216         assert(s);
 217         assert(s->txt_data_items);
 218         assert(s->manager);
 219
 220         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 221         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 222         LIST_FOREACH(items, txt_data, s->txt_data_items)
 223                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 224
 225         r = dnssd_render_instance_name(s, &n);
 226         if (r < 0)
 227                 return r;
 228
 229         r = dns_name_concat(s->type, "local", 0, &service_name);
 230         if (r < 0)
 231                 return r;
 232         r = dns_name_concat(n, service_name, 0, &full_name);
 233         if (r < 0)
 234                 return r;
 235
 236         LIST_FOREACH(items, txt_data, s->txt_data_items) {
 237                 txt_data->rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_TXT,
 238                                                             full_name);
 239                 if (!txt_data->rr)
 240                         goto oom;
 241
 242                 txt_data->rr->ttl = MDNS_DEFAULT_TTL;
 243                 txt_data->rr->txt.items = dns_txt_item_copy(txt_data->txt);
 244                 if (!txt_data->rr->txt.items)
 245                         goto oom;
 246         }
 247
 248         s->ptr_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
 249                                                  service_name);
 250         if (!s->ptr_rr)
 251                 goto oom;
 252
 253         s->ptr_rr->ttl = MDNS_DEFAULT_TTL;
 254         s->ptr_rr->ptr.name = strdup(full_name);
 255         if (!s->ptr_rr->ptr.name)
 256                 goto oom;
 257
 258         s->srv_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SRV,
 259                                                  full_name);
 260         if (!s->srv_rr)
 261                 goto oom;
 262
 263         s->srv_rr->ttl = MDNS_DEFAULT_TTL;
 264         s->srv_rr->srv.priority = s->priority;
 265         s->srv_rr->srv.weight = s->weight;
 266         s->srv_rr->srv.port = s->port;
 267         s->srv_rr->srv.name = strdup(s->manager->mdns_hostname);
 268         if (!s->srv_rr->srv.name)
 269                 goto oom;
 270
 271         return 0;
 272
 273 oom:
 274         LIST_FOREACH(items, txt_data, s->txt_data_items)
 275                 txt_data->rr = dns_resource_record_unref(txt_data->rr);
 276         s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
 277         s->srv_rr = dns_resource_record_unref(s->srv_rr);
 278         return -ENOMEM;
 279 }
 280
 281 int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item) {
 282         size_t length;
 283         DnsTxtItem *i;
 284
 285         length = strlen(key);
 286
 287         if (!isempty(value))
 288                 length += strlen(value) + 1; /* length of value plus '=' */
 289
 290         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 291         if (!i)
 292                 return -ENOMEM;
 293
 294         memcpy(i->data, key, strlen(key));
 295         if (!isempty(value)) {
 296                 memcpy(i->data + strlen(key), "=", 1);
 297                 memcpy(i->data + strlen(key) + 1, value, strlen(value));
 298         }
 299         i->length = length;
 300
 301         *ret_item = TAKE_PTR(i);
 302
 303         return 0;
 304 }
 305
 306 int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t size, DnsTxtItem **ret_item) {
 307         size_t length;
 308         DnsTxtItem *i;
 309
 310         length = strlen(key);
 311
 312         if (size > 0)
 313                 length += size + 1; /* size of date plus '=' */
 314
 315         i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
 316         if (!i)
 317                 return -ENOMEM;
 318
 319         memcpy(i->data, key, strlen(key));
 320         if (size > 0) {
 321                 memcpy(i->data + strlen(key), "=", 1);
 322                 memcpy(i->data + strlen(key) + 1, data, size);
 323         }
 324         i->length = length;
 325
 326         *ret_item = TAKE_PTR(i);
 327
 328         return 0;
 329 }
 330
 331 int dnssd_signal_conflict(Manager *manager, const char *name) {
 332         DnssdService *s;
 333         int r;
 334
 335         if (sd_bus_is_ready(manager->bus) <= 0)
 336                 return 0;
 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                                 return log_error_errno(r, "Can't get D-BUS object path: %m");
 350
 351                         r = sd_bus_emit_signal(manager->bus,
 352                                                path,
 353                                                "org.freedesktop.resolve1.DnssdService",
 354                                                "Conflicted",
 355                                                NULL);
 356                         if (r < 0)
 357                                 return log_error_errno(r, "Cannot emit signal: %m");
 358
 359                         break;
 360                 }
 361         }
 362
 363         return 0;
 364 }