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-rw-r--r--src/resolve/resolved-dnssd.c362
1 files changed, 362 insertions, 0 deletions
diff --git a/src/resolve/resolved-dnssd.c b/src/resolve/resolved-dnssd.c
new file mode 100644
index 0000000..994771e
--- /dev/null
+++ b/src/resolve/resolved-dnssd.c
@@ -0,0 +1,362 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "conf-files.h"
+#include "conf-parser.h"
+#include "constants.h"
+#include "resolved-dnssd.h"
+#include "resolved-dns-rr.h"
+#include "resolved-manager.h"
+#include "resolved-conf.h"
+#include "specifier.h"
+#include "strv.h"
+
+#define DNSSD_SERVICE_DIRS ((const char* const*) CONF_PATHS_STRV("systemd/dnssd"))
+
+DnssdTxtData *dnssd_txtdata_free(DnssdTxtData *txt_data) {
+ if (!txt_data)
+ return NULL;
+
+ dns_resource_record_unref(txt_data->rr);
+ dns_txt_item_free_all(txt_data->txts);
+
+ return mfree(txt_data);
+}
+
+DnssdTxtData *dnssd_txtdata_free_all(DnssdTxtData *txt_data) {
+ DnssdTxtData *next;
+
+ if (!txt_data)
+ return NULL;
+
+ next = txt_data->items_next;
+
+ dnssd_txtdata_free(txt_data);
+
+ return dnssd_txtdata_free_all(next);
+}
+
+DnssdService *dnssd_service_free(DnssdService *service) {
+ if (!service)
+ return NULL;
+
+ if (service->manager)
+ hashmap_remove(service->manager->dnssd_services, service->name);
+
+ dns_resource_record_unref(service->ptr_rr);
+ dns_resource_record_unref(service->srv_rr);
+
+ dnssd_txtdata_free_all(service->txt_data_items);
+
+ free(service->filename);
+ free(service->name);
+ free(service->type);
+ free(service->name_template);
+
+ return mfree(service);
+}
+
+static int dnssd_service_load(Manager *manager, const char *filename) {
+ _cleanup_(dnssd_service_freep) DnssdService *service = NULL;
+ _cleanup_(dnssd_txtdata_freep) DnssdTxtData *txt_data = NULL;
+ char *d;
+ const char *dropin_dirname;
+ int r;
+
+ assert(manager);
+ assert(filename);
+
+ service = new0(DnssdService, 1);
+ if (!service)
+ return log_oom();
+
+ service->filename = strdup(filename);
+ if (!service->filename)
+ return log_oom();
+
+ service->name = strdup(basename(filename));
+ if (!service->name)
+ return log_oom();
+
+ d = endswith(service->name, ".dnssd");
+ if (!d)
+ return -EINVAL;
+
+ assert(streq(d, ".dnssd"));
+
+ *d = '\0';
+
+ dropin_dirname = strjoina(service->name, ".dnssd.d");
+
+ r = config_parse_many(
+ STRV_MAKE_CONST(filename), DNSSD_SERVICE_DIRS, dropin_dirname, /* root = */ NULL,
+ "Service\0",
+ config_item_perf_lookup, resolved_dnssd_gperf_lookup,
+ CONFIG_PARSE_WARN,
+ service,
+ NULL,
+ NULL);
+ if (r < 0)
+ return r;
+
+ if (!service->name_template)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "%s doesn't define service instance name",
+ service->name);
+
+ if (!service->type)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "%s doesn't define service type",
+ service->name);
+
+ if (!service->txt_data_items) {
+ txt_data = new0(DnssdTxtData, 1);
+ if (!txt_data)
+ return log_oom();
+
+ r = dns_txt_item_new_empty(&txt_data->txts);
+ if (r < 0)
+ return r;
+
+ LIST_PREPEND(items, service->txt_data_items, txt_data);
+ TAKE_PTR(txt_data);
+ }
+
+ r = hashmap_ensure_put(&manager->dnssd_services, &string_hash_ops, service->name, service);
+ if (r < 0)
+ return r;
+
+ service->manager = manager;
+
+ r = dnssd_update_rrs(service);
+ if (r < 0)
+ return r;
+
+ TAKE_PTR(service);
+
+ return 0;
+}
+
+static int specifier_dnssd_hostname(char specifier, const void *data, const char *root, const void *userdata, char **ret) {
+ const Manager *m = ASSERT_PTR(userdata);
+ char *n;
+
+ assert(m->llmnr_hostname);
+
+ n = strdup(m->llmnr_hostname);
+ if (!n)
+ return -ENOMEM;
+
+ *ret = n;
+ return 0;
+}
+
+int dnssd_render_instance_name(Manager *m, DnssdService *s, char **ret) {
+ static const Specifier specifier_table[] = {
+ { 'a', specifier_architecture, NULL },
+ { 'b', specifier_boot_id, NULL },
+ { 'B', specifier_os_build_id, NULL },
+ { 'H', specifier_dnssd_hostname, NULL },
+ { 'm', specifier_machine_id, NULL },
+ { 'o', specifier_os_id, NULL },
+ { 'v', specifier_kernel_release, NULL },
+ { 'w', specifier_os_version_id, NULL },
+ { 'W', specifier_os_variant_id, NULL },
+ {}
+ };
+ _cleanup_free_ char *name = NULL;
+ int r;
+
+ assert(m);
+ assert(s);
+ assert(s->name_template);
+
+ r = specifier_printf(s->name_template, DNS_LABEL_MAX, specifier_table, NULL, m, &name);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to replace specifiers: %m");
+
+ if (!dns_service_name_is_valid(name))
+ return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+ "Service instance name '%s' is invalid.",
+ name);
+
+ if (ret)
+ *ret = TAKE_PTR(name);
+
+ return 0;
+}
+
+int dnssd_load(Manager *manager) {
+ _cleanup_strv_free_ char **files = NULL;
+ int r;
+
+ assert(manager);
+
+ if (manager->mdns_support != RESOLVE_SUPPORT_YES)
+ return 0;
+
+ r = conf_files_list_strv(&files, ".dnssd", NULL, 0, DNSSD_SERVICE_DIRS);
+ if (r < 0)
+ return log_error_errno(r, "Failed to enumerate .dnssd files: %m");
+
+ STRV_FOREACH_BACKWARDS(f, files) {
+ r = dnssd_service_load(manager, *f);
+ if (r < 0)
+ log_warning_errno(r, "Failed to load '%s': %m", *f);
+ }
+
+ return 0;
+}
+
+int dnssd_update_rrs(DnssdService *s) {
+ _cleanup_free_ char *n = NULL, *service_name = NULL, *full_name = NULL;
+ int r;
+
+ assert(s);
+ assert(s->txt_data_items);
+ assert(s->manager);
+
+ s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
+ s->srv_rr = dns_resource_record_unref(s->srv_rr);
+ LIST_FOREACH(items, txt_data, s->txt_data_items)
+ txt_data->rr = dns_resource_record_unref(txt_data->rr);
+
+ r = dnssd_render_instance_name(s->manager, s, &n);
+ if (r < 0)
+ return r;
+
+ r = dns_name_concat(s->type, "local", 0, &service_name);
+ if (r < 0)
+ return r;
+ r = dns_name_concat(n, service_name, 0, &full_name);
+ if (r < 0)
+ return r;
+
+ LIST_FOREACH(items, txt_data, s->txt_data_items) {
+ txt_data->rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_TXT,
+ full_name);
+ if (!txt_data->rr)
+ goto oom;
+
+ txt_data->rr->ttl = MDNS_DEFAULT_TTL;
+ txt_data->rr->txt.items = dns_txt_item_copy(txt_data->txts);
+ if (!txt_data->rr->txt.items)
+ goto oom;
+ }
+
+ s->ptr_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
+ service_name);
+ if (!s->ptr_rr)
+ goto oom;
+
+ s->ptr_rr->ttl = MDNS_DEFAULT_TTL;
+ s->ptr_rr->ptr.name = strdup(full_name);
+ if (!s->ptr_rr->ptr.name)
+ goto oom;
+
+ s->srv_rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SRV,
+ full_name);
+ if (!s->srv_rr)
+ goto oom;
+
+ s->srv_rr->ttl = MDNS_DEFAULT_TTL;
+ s->srv_rr->srv.priority = s->priority;
+ s->srv_rr->srv.weight = s->weight;
+ s->srv_rr->srv.port = s->port;
+ s->srv_rr->srv.name = strdup(s->manager->mdns_hostname);
+ if (!s->srv_rr->srv.name)
+ goto oom;
+
+ return 0;
+
+oom:
+ LIST_FOREACH(items, txt_data, s->txt_data_items)
+ txt_data->rr = dns_resource_record_unref(txt_data->rr);
+ s->ptr_rr = dns_resource_record_unref(s->ptr_rr);
+ s->srv_rr = dns_resource_record_unref(s->srv_rr);
+ return -ENOMEM;
+}
+
+int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtItem **ret_item) {
+ size_t length;
+ DnsTxtItem *i;
+
+ length = strlen(key);
+
+ if (!isempty(value))
+ length += strlen(value) + 1; /* length of value plus '=' */
+
+ i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
+ if (!i)
+ return -ENOMEM;
+
+ memcpy(i->data, key, strlen(key));
+ if (!isempty(value)) {
+ memcpy(i->data + strlen(key), "=", 1);
+ memcpy(i->data + strlen(key) + 1, value, strlen(value));
+ }
+ i->length = length;
+
+ *ret_item = TAKE_PTR(i);
+
+ return 0;
+}
+
+int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t size, DnsTxtItem **ret_item) {
+ size_t length;
+ DnsTxtItem *i;
+
+ length = strlen(key);
+
+ if (size > 0)
+ length += size + 1; /* size of date plus '=' */
+
+ i = malloc0(offsetof(DnsTxtItem, data) + length + 1); /* for safety reasons we add an extra NUL byte */
+ if (!i)
+ return -ENOMEM;
+
+ memcpy(i->data, key, strlen(key));
+ if (size > 0) {
+ memcpy(i->data + strlen(key), "=", 1);
+ memcpy(i->data + strlen(key) + 1, data, size);
+ }
+ i->length = length;
+
+ *ret_item = TAKE_PTR(i);
+
+ return 0;
+}
+
+int dnssd_signal_conflict(Manager *manager, const char *name) {
+ DnssdService *s;
+ int r;
+
+ if (sd_bus_is_ready(manager->bus) <= 0)
+ return 0;
+
+ HASHMAP_FOREACH(s, manager->dnssd_services) {
+ if (s->withdrawn)
+ continue;
+
+ if (dns_name_equal(dns_resource_key_name(s->srv_rr->key), name)) {
+ _cleanup_free_ char *path = NULL;
+
+ s->withdrawn = true;
+
+ r = sd_bus_path_encode("/org/freedesktop/resolve1/dnssd", s->name, &path);
+ if (r < 0)
+ return log_error_errno(r, "Can't get D-BUS object path: %m");
+
+ r = sd_bus_emit_signal(manager->bus,
+ path,
+ "org.freedesktop.resolve1.DnssdService",
+ "Conflicted",
+ NULL);
+ if (r < 0)
+ return log_error_errno(r, "Cannot emit signal: %m");
+
+ break;
+ }
+ }
+
+ return 0;
+}