diff options
Diffstat (limited to 'src/resolve/resolved-dnssd.c')
| -rw-r--r-- | src/resolve/resolved-dnssd.c | 362 |
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; +} |