Use service discovery in backends

Integrate the failover improvements with our back ends. The DNS domain
used in the SRV query is always the SSSD domain name.

Please note that this patch changes the default value of ldap_uri from
"ldap://localhost" to "NULL" in order to use service discovery with no
server set.

1 files changed, 49 insertions, 8 deletions

diff --git a/src/providers/ldap/ldap_common.c b/src/providers/ldap/ldap_common.c
index 90ec7e2e7..03b2133a8 100644
--- a/src/providers/ldap/ldap_common.c
+++ b/src/providers/ldap/ldap_common.c
@@ -31,7 +31,7 @@
 int ldap_child_debug_fd = -1;
 
 struct dp_option default_basic_opts[] = {
-    { "ldap_uri", DP_OPT_STRING, { "ldap://localhost" }, NULL_STRING },
+    { "ldap_uri", DP_OPT_STRING, NULL_STRING, NULL_STRING },
     { "ldap_search_base", DP_OPT_STRING, { "dc=example,dc=com" }, NULL_STRING },
     { "ldap_default_bind_dn", DP_OPT_STRING, NULL_STRING, NULL_STRING },
     { "ldap_default_authtok_type", DP_OPT_STRING, NULL_STRING, NULL_STRING},
@@ -63,7 +63,8 @@ struct dp_option default_basic_opts[] = {
     { "krb5_realm", DP_OPT_STRING, NULL_STRING, NULL_STRING },
     { "ldap_pwd_policy", DP_OPT_STRING, { "none" } , NULL_STRING },
     { "ldap_referrals", DP_OPT_BOOL, BOOL_TRUE, BOOL_TRUE },
-    { "account_cache_expiration", DP_OPT_NUMBER, { .number = 0 }, NULL_NUMBER }
+    { "account_cache_expiration", DP_OPT_NUMBER, { .number = 0 }, NULL_NUMBER },
+    { "ldap_dns_service_name", DP_OPT_STRING, { SSS_LDAP_SRV_NAME }, NULL_STRING }
 };
 
 struct sdap_attr_map generic_attr_map[] = {
@@ -537,30 +538,46 @@ static void sdap_uri_callback(void *private_data, struct fo_server *server)
     if (!service) return;
 
     tmp = (const char *)fo_get_server_user_data(server);
-    if (tmp && ldap_is_ldap_url(tmp)) {
-        new_uri = talloc_strdup(service, tmp);
+
+    if (fo_is_srv_lookup(server)) {
+        if (!tmp) {
+            DEBUG(1, ("Unknown service, using ldap\n"));
+            tmp = SSS_LDAP_SRV_NAME;
+        }
+        new_uri = talloc_asprintf(service, "%s://%s:%d",
+                                  tmp,
+                                  fo_get_server_name(server),
+                                  fo_get_server_port(server));
     } else {
-        new_uri = talloc_asprintf(service, "ldap://%s",
-                                  fo_get_server_name(server));
+        if (tmp && ldap_is_ldap_url(tmp)) {
+            new_uri = talloc_strdup(service, tmp);
+        } else {
+            new_uri = talloc_asprintf(service, "ldap://%s",
+                                    fo_get_server_name(server));
+        }
     }
+
     if (!new_uri) {
         DEBUG(2, ("Failed to copy URI ...\n"));
         return;
     }
 
+    DEBUG(6, ("Constructed uri '%s'\n", new_uri));
+
     /* free old one and replace with new one */
     talloc_zfree(service->uri);
     service->uri = new_uri;
 }
 
 int sdap_service_init(TALLOC_CTX *memctx, struct be_ctx *ctx,
-                      const char *service_name, const char *urls,
-                      struct sdap_service **_service)
+                      const char *service_name, const char *dns_service_name,
+                      const char *urls, struct sdap_service **_service)
 {
     TALLOC_CTX *tmp_ctx;
     struct sdap_service *service;
     LDAPURLDesc *lud;
     char **list = NULL;
+    char *srv_user_data;
     int ret;
     int i;
 
@@ -587,6 +604,10 @@ int sdap_service_init(TALLOC_CTX *memctx, struct be_ctx *ctx,
         goto done;
     }
 
+    if (!urls) {
+        urls = BE_SRV_IDENTIFIER;
+    }
+
     /* split server parm into a list */
     ret = split_on_separator(tmp_ctx, urls, ',', true, &list, NULL);
     if (ret != EOK) {
@@ -596,6 +617,26 @@ int sdap_service_init(TALLOC_CTX *memctx, struct be_ctx *ctx,
 
     /* now for each URI add a new server to the failover service */
     for (i = 0; list[i]; i++) {
+        if (be_fo_is_srv_identifier(list[i])) {
+            srv_user_data = talloc_strdup(service, dns_service_name);
+            if (!srv_user_data) {
+                ret = ENOMEM;
+                goto done;
+            }
+
+            ret = be_fo_add_srv_server(ctx, service_name,
+                                       dns_service_name, FO_PROTO_TCP,
+                                       ctx->domain->name,
+                                       srv_user_data);
+            if (ret) {
+                DEBUG(0, ("Failed to add server\n"));
+                goto done;
+            }
+
+            DEBUG(6, ("Added service lookup\n"));
+            continue;
+        }
+
         ret = ldap_url_parse(list[i], &lud);
         if (ret != LDAP_SUCCESS) {
             DEBUG(0, ("Failed to parse ldap URI (%s)!\n", list[i]));