diff options
Diffstat (limited to 'server/providers/fail_over.c')
| -rw-r--r-- | server/providers/fail_over.c | 651 |
1 files changed, 0 insertions, 651 deletions
diff --git a/server/providers/fail_over.c b/server/providers/fail_over.c deleted file mode 100644 index 7560b89ee..000000000 --- a/server/providers/fail_over.c +++ /dev/null @@ -1,651 +0,0 @@ -/* - SSSD - - Fail over helper functions. - - Authors: - Martin Nagy <mnagy@redhat.com> - - Copyright (C) Red Hat, Inc 2009 - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. -*/ - -#include <sys/time.h> - -#include <errno.h> -#include <stdbool.h> -#include <strings.h> -#include <talloc.h> - -#include "util/dlinklist.h" -#include "util/refcount.h" -#include "util/util.h" -#include "providers/fail_over.h" -#include "resolv/async_resolv.h" - -#define STATUS_DIFF(p, now) ((now).tv_sec - (p)->last_status_change.tv_sec) -#define SERVER_NAME(s) ((s)->common ? (s)->common->name : "(no name)") - -#define DEFAULT_PORT_STATUS PORT_NEUTRAL -#define DEFAULT_SERVER_STATUS SERVER_NAME_NOT_RESOLVED - -struct fo_ctx { - struct fo_service *service_list; - struct server_common *server_common_list; - - /* Settings. */ - time_t retry_timeout; -}; - -struct fo_service { - struct fo_service *prev; - struct fo_service *next; - - struct fo_ctx *ctx; - char *name; - struct fo_server *active_server; - struct fo_server *last_tried_server; - struct fo_server *server_list; -}; - -struct fo_server { - struct fo_server *prev; - struct fo_server *next; - - void *user_data; - int port; - int port_status; - struct fo_service *service; - struct timeval last_status_change; - struct server_common *common; -}; - -struct server_common { - REFCOUNT_COMMON; - - struct server_common *prev; - struct server_common *next; - - char *name; - struct hostent *hostent; - struct resolve_service_request *request_list; - int server_status; - struct timeval last_status_change; -}; - -struct resolve_service_request { - struct resolve_service_request *prev; - struct resolve_service_request *next; - - struct server_common *server_common; - struct tevent_req *req; -}; - -struct status { - int value; - struct timeval last_change; -}; - -struct fo_ctx * -fo_context_init(TALLOC_CTX *mem_ctx, time_t retry_timeout) -{ - struct fo_ctx *ctx; - - ctx = talloc_zero(mem_ctx, struct fo_ctx); - if (ctx == NULL) { - DEBUG(1, ("No memory\n")); - return NULL; - } - - ctx->retry_timeout = retry_timeout; - - DEBUG(3, ("Created new fail over context, retry timeout is %d\n", - retry_timeout)); - return ctx; -} - -static const char * -str_port_status(enum port_status status) -{ - switch (status) { - case PORT_NEUTRAL: - return "neutral"; - case PORT_WORKING: - return "working"; - case PORT_NOT_WORKING: - return "not working"; - } - - return "unknown port status"; -} - -static const char * -str_server_status(enum server_status status) -{ - switch (status) { - case SERVER_NAME_NOT_RESOLVED: - return "name not resolved"; - case SERVER_RESOLVING_NAME: - return "resolving name"; - case SERVER_NAME_RESOLVED: - return "name resolved"; - case SERVER_WORKING: - return "working"; - case SERVER_NOT_WORKING: - return "not working"; - } - - return "unknown server status"; -} - -/* - * This function will return the status of the server. If the status was - * last updated a long time ago, we will first reset the status. - */ -static enum server_status -get_server_status(struct fo_server *server) -{ - struct timeval tv; - time_t timeout; - - if (server->common == NULL) - return SERVER_NAME_RESOLVED; - - DEBUG(7, ("Status of server '%s' is '%s'\n", SERVER_NAME(server), - str_server_status(server->common->server_status))); - - timeout = server->service->ctx->retry_timeout; - if (timeout != 0 && server->common->server_status == SERVER_NOT_WORKING) { - gettimeofday(&tv, NULL); - if (STATUS_DIFF(server->common, tv) > timeout) { - DEBUG(4, ("Reseting the server status of '%s'\n", - SERVER_NAME(server))); - server->common->server_status = SERVER_NAME_NOT_RESOLVED; - server->last_status_change.tv_sec = 0; - } - } - - return server->common->server_status; -} - -/* - * This function will return the status of the service. If the status was - * last updated a long time ago, we will first reset the status. - */ -static enum port_status -get_port_status(struct fo_server *server) -{ - struct timeval tv; - time_t timeout; - - DEBUG(7, ("Port status of port %d for server '%s' is '%s'\n", server->port, - SERVER_NAME(server), str_port_status(server->port_status))); - - timeout = server->service->ctx->retry_timeout; - if (timeout != 0 && server->port_status == PORT_NOT_WORKING) { - gettimeofday(&tv, NULL); - if (STATUS_DIFF(server, tv) > timeout) { - DEBUG(4, ("Reseting the status of port %d for server '%s'\n", - server->port, SERVER_NAME(server))); - server->port_status = PORT_NEUTRAL; - server->last_status_change.tv_sec = tv.tv_sec; - } - } - - return server->port_status; -} - -static int -server_works(struct fo_server *server) -{ - if (get_server_status(server) == SERVER_NOT_WORKING) - return 0; - - return 1; -} - -static int -service_works(struct fo_server *server) -{ - if (!server_works(server)) - return 0; - if (get_port_status(server) == PORT_NOT_WORKING) - return 0; - - return 1; -} - -static int -service_destructor(struct fo_service *service) -{ - DLIST_REMOVE(service->ctx->service_list, service); - return 0; -} - -int -fo_new_service(struct fo_ctx *ctx, const char *name, - struct fo_service **_service) -{ - struct fo_service *service; - int ret; - - DEBUG(3, ("Creating new service '%s'\n", name)); - ret = fo_get_service(ctx, name, &service); - if (ret == EOK) { - DEBUG(5, ("Service '%s' already exists\n", name)); - if (_service) { - *_service = service; - } - return EEXIST; - } else if (ret != ENOENT) { - return ret; - } - - service = talloc_zero(ctx, struct fo_service); - if (service == NULL) - return ENOMEM; - - service->name = talloc_strdup(service, name); - if (service->name == NULL) { - talloc_free(service); - return ENOMEM; - } - - service->ctx = ctx; - DLIST_ADD(ctx->service_list, service); - - talloc_set_destructor(service, service_destructor); - if (_service) { - *_service = service; - } - - return EOK; -} - -int -fo_get_service(struct fo_ctx *ctx, const char *name, - struct fo_service **_service) -{ - struct fo_service *service; - - DLIST_FOR_EACH(service, ctx->service_list) { - if (!strcmp(name, service->name)) { - *_service = service; - return EOK; - } - } - - return ENOENT; -} - -static int -get_server_common(TALLOC_CTX *mem_ctx, struct fo_ctx *ctx, const char *name, - struct server_common **_common) -{ - struct server_common *common; - - DLIST_FOR_EACH(common, ctx->server_common_list) { - if (!strcmp(name, common->name)) { - *_common = rc_reference(mem_ctx, struct server_common, common); - if (_common == NULL) - return ENOMEM; - return EOK; - } - } - - return ENOENT; -} - -static struct server_common * -create_server_common(TALLOC_CTX *mem_ctx, struct fo_ctx *ctx, const char *name) -{ - struct server_common *common; - - common = rc_alloc(mem_ctx, struct server_common); - if (common == NULL) - return NULL; - - common->name = talloc_strdup(common, name); - if (common->name == NULL) { - talloc_free(common); - return NULL; - } - - common->prev = NULL; - common->next = NULL; - common->hostent = NULL; - common->request_list = NULL; - common->server_status = DEFAULT_SERVER_STATUS; - common->last_status_change.tv_sec = 0; - common->last_status_change.tv_usec = 0; - - DLIST_ADD_END(ctx->server_common_list, common, struct server_common *); - return common; -} - -int -fo_add_server(struct fo_service *service, const char *name, int port, - void *user_data) -{ - struct fo_server *server; - int ret; - - DEBUG(3, ("Adding new server '%s', to service '%s'\n", - name ? name : "(no name)", service->name)); - DLIST_FOR_EACH(server, service->server_list) { - if (server->port != port || server->user_data != user_data) - continue; - if (name == NULL && server->common == NULL) { - return EEXIST; - } else if (name != NULL && server->common != NULL) { - if (!strcmp(name, server->common->name)) - return EEXIST; - } - } - - server = talloc_zero(service, struct fo_server); - if (server == NULL) - return ENOMEM; - - server->port = port; - server->user_data = user_data; - server->service = service; - server->port_status = DEFAULT_PORT_STATUS; - - if (name != NULL) { - ret = get_server_common(server, service->ctx, name, &server->common); - if (ret == ENOENT) { - server->common = create_server_common(server, service->ctx, name); - if (server->common == NULL) { - talloc_free(server); - return ENOMEM; - } - } else if (ret != EOK) { - talloc_free(server); - return ret; - } - } - - DLIST_ADD_END(service->server_list, server, struct fo_server *); - - return EOK; -} - -static int -get_first_server_entity(struct fo_service *service, struct fo_server **_server) -{ - struct fo_server *server; - - /* If we already have a working server, use that one. */ - server = service->active_server; - if (server != NULL) { - if (service_works(server)) { - goto done; - } - service->active_server = NULL; - } - - /* - * Otherwise iterate through the server list. - */ - - /* First, try servers after the last one we tried. */ - if (service->last_tried_server != NULL) { - DLIST_FOR_EACH(server, service->last_tried_server->next) { - if (service_works(server)) { - goto done; - } - } - } - - /* If none were found, try at the start. */ - DLIST_FOR_EACH(server, service->server_list) { - if (service_works(server)) { - goto done; - } - if (server == service->last_tried_server) { - break; - } - } - - service->last_tried_server = NULL; - return ENOENT; - -done: - service->last_tried_server = server; - *_server = server; - return EOK; -} - -static int -resolve_service_request_destructor(struct resolve_service_request *request) -{ - DLIST_REMOVE(request->server_common->request_list, request); - return 0; -} - -static int -set_lookup_hook(struct fo_server *server, struct tevent_req *req) -{ - struct resolve_service_request *request; - - request = talloc(req, struct resolve_service_request); - if (request == NULL) { - DEBUG(1, ("No memory\n")); - talloc_free(request); - return ENOMEM; - } - request->server_common = server->common; - request->req = req; - DLIST_ADD(server->common->request_list, request); - talloc_set_destructor(request, resolve_service_request_destructor); - - return EOK; -} - -/******************************************************************* - * Get server to connect to. * - *******************************************************************/ - -struct resolve_service_state { - struct fo_server *server; -}; - -static void fo_resolve_service_done(struct tevent_req *subreq); - -struct tevent_req * -fo_resolve_service_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, - struct resolv_ctx *resolv, struct fo_service *service) -{ - int ret; - struct fo_server *server; - struct tevent_req *req; - struct tevent_req *subreq; - struct resolve_service_state *state; - - DEBUG(4, ("Trying to resolve service '%s'\n", service->name)); - req = tevent_req_create(mem_ctx, &state, struct resolve_service_state); - if (req == NULL) - return NULL; - - ret = get_first_server_entity(service, &server); - if (ret != EOK) { - DEBUG(1, ("No available servers for service '%s'\n", service->name)); - goto done; - } - - state->server = server; - - if (server->common == NULL) { - /* This server doesn't have a name, we don't do name resolution. */ - tevent_req_done(req); - tevent_req_post(req, ev); - return req; - } - - switch (get_server_status(server)) { - case SERVER_NAME_NOT_RESOLVED: /* Request name resolution. */ - subreq = resolv_gethostbyname_send(server->common, ev, resolv, - server->common->name); - if (subreq == NULL) { - ret = ENOMEM; - goto done; - } - tevent_req_set_callback(subreq, fo_resolve_service_done, server->common); - fo_set_server_status(server, SERVER_RESOLVING_NAME); - /* FALLTHROUGH */ - case SERVER_RESOLVING_NAME: - /* Name resolution is already under way. Just add ourselves into the - * waiting queue so we get notified after the operation is finished. */ - ret = set_lookup_hook(server, req); - if (ret != EOK) - goto done; - break; - default: /* The name is already resolved. Return immediately. */ - tevent_req_done(req); - tevent_req_post(req, ev); - break; - } - -done: - if (ret != EOK) { - tevent_req_error(req, ret); - tevent_req_post(req, ev); - } - return req; -} - -static void set_server_common_status(struct server_common *common, - enum server_status status); - -static void -fo_resolve_service_done(struct tevent_req *subreq) -{ - int resolv_status; - struct resolve_service_request *request; - struct server_common *common; - int ret; - - common = tevent_req_callback_data(subreq, struct server_common); - - if (common->hostent != NULL) { - talloc_zfree(common->hostent); - } - - ret = resolv_gethostbyname_recv(subreq, common, - &resolv_status, NULL, &common->hostent); - talloc_free(subreq); - if (ret != EOK) { - DEBUG(1, ("Failed to resolve server '%s': %s\n", common->name, - resolv_strerror(resolv_status))); - set_server_common_status(common, SERVER_NOT_WORKING); - } else { - set_server_common_status(common, SERVER_NAME_RESOLVED); - } - - /* Take care of all requests for this server. */ - while ((request = common->request_list) != NULL) { - DLIST_REMOVE(common->request_list, request); - if (resolv_status) { - /* FIXME FIXME: resolv_status is an ARES error. - * but any caller will expect classic error codes. - * also the send() function may return ENOENT, so this mix - * IS explosive (ENOENT = 2 = ARES_EFORMER) */ - tevent_req_error(request->req, resolv_status); - } else { - tevent_req_done(request->req); - } - } -} - -int -fo_resolve_service_recv(struct tevent_req *req, struct fo_server **server) -{ - struct resolve_service_state *state; - - state = tevent_req_data(req, struct resolve_service_state); - - /* always return the server if asked for, otherwise the caller - * cannot mark it as faulty in case we return an error */ - if (server) - *server = state->server; - - TEVENT_REQ_RETURN_ON_ERROR(req); - - return EOK; -} - -static void -set_server_common_status(struct server_common *common, - enum server_status status) -{ - DEBUG(4, ("Marking server '%s' as '%s'\n", common->name, - str_server_status(status))); - - common->server_status = status; - gettimeofday(&common->last_status_change, NULL); -} - -void -fo_set_server_status(struct fo_server *server, enum server_status status) -{ - if (server->common == NULL) { - DEBUG(1, ("Bug: Trying to set server status of a name-less server\n")); - return; - } - - set_server_common_status(server->common, status); -} - -void -fo_set_port_status(struct fo_server *server, enum port_status status) -{ - DEBUG(4, ("Marking port %d of server '%s' as '%s'\n", server->port, - SERVER_NAME(server), str_port_status(status))); - - server->port_status = status; - gettimeofday(&server->last_status_change, NULL); - if (status == PORT_WORKING) { - fo_set_server_status(server, SERVER_WORKING); - server->service->active_server = server; - } -} - -void * -fo_get_server_user_data(struct fo_server *server) -{ - return server->user_data; -} - -int -fo_get_server_port(struct fo_server *server) -{ - return server->port; -} - -const char *fo_get_server_name(struct fo_server *server) -{ - return server->common->name; -} - -struct hostent * -fo_get_server_hostent(struct fo_server *server) -{ - if (server->common == NULL) { - DEBUG(1, ("Bug: Trying to get hostent from a name-less server\n")); - return NULL; - } - return server->common->hostent; -} |