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authorPavel Březina <pbrezina@redhat.com>2013-03-29 15:57:20 +0100
committerJakub Hrozek <jhrozek@redhat.com>2013-04-10 15:36:55 +0200
commit673d4c1932fa4ab1496499207d8627970d0b7561 (patch)
tree9e2842eb3fe8bdaa5c46f8c87ff322d99309eba0 /src/resolv
parentca261795ce61c41d7e62217ccb2ee913923040ff (diff)
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resolv: add resolv_discover_srv request to resolv utils
Diffstat (limited to 'src/resolv')
-rw-r--r--src/resolv/async_resolv.h13
-rw-r--r--src/resolv/async_resolv_utils.c181
2 files changed, 194 insertions, 0 deletions
diff --git a/src/resolv/async_resolv.h b/src/resolv/async_resolv.h
index cba6ca8d..3a025588 100644
--- a/src/resolv/async_resolv.h
+++ b/src/resolv/async_resolv.h
@@ -170,4 +170,17 @@ errno_t resolv_get_domain_recv(TALLOC_CTX *mem_ctx,
struct tevent_req *req,
char **_dns_domain);
+struct tevent_req *
+resolv_discover_srv_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ struct resolv_ctx *resolv_ctx,
+ const char *service,
+ const char *protocol,
+ const char **discovery_domains);
+
+errno_t resolv_discover_srv_recv(TALLOC_CTX *mem_ctx,
+ struct tevent_req *req,
+ struct ares_srv_reply **_reply_list,
+ char **_dns_domain);
+
#endif /* __ASYNC_RESOLV_H__ */
diff --git a/src/resolv/async_resolv_utils.c b/src/resolv/async_resolv_utils.c
index 9f55e01b..0cb373ca 100644
--- a/src/resolv/async_resolv_utils.c
+++ b/src/resolv/async_resolv_utils.c
@@ -152,3 +152,184 @@ errno_t resolv_get_domain_recv(TALLOC_CTX *mem_ctx,
return EOK;
}
+
+struct resolv_discover_srv_state {
+ struct tevent_context *ev;
+ struct resolv_ctx *resolv_ctx;
+ const char *service;
+ const char *protocol;
+ const char **discovery_domains;
+ int domain_index;
+
+ struct ares_srv_reply *reply_list;
+};
+
+static errno_t resolv_discover_srv_next_domain(struct tevent_req *req);
+static void resolv_discover_srv_done(struct tevent_req *subreq);
+
+struct tevent_req *resolv_discover_srv_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ struct resolv_ctx *resolv_ctx,
+ const char *service,
+ const char *protocol,
+ const char **discovery_domains)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *req = NULL;
+ errno_t ret;
+
+ req = tevent_req_create(mem_ctx, &state,
+ struct resolv_discover_srv_state);
+ if (req == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE, ("tevent_req_create() failed\n"));
+ return NULL;
+ }
+
+ if (resolv_ctx == NULL || service == NULL || protocol == NULL
+ || discovery_domains == NULL) {
+ ret = EINVAL;
+ goto immediately;
+ }
+
+ state->ev = ev;
+ state->resolv_ctx = resolv_ctx;
+ state->discovery_domains = discovery_domains;
+ state->service = service;
+ state->protocol = protocol;
+ state->domain_index = 0;
+
+ ret = resolv_discover_srv_next_domain(req);
+ if (ret != EAGAIN) {
+ goto immediately;
+ }
+
+ return req;
+
+immediately:
+ if (ret == EOK) {
+ tevent_req_done(req);
+ } else {
+ tevent_req_error(req, ret);
+ }
+ tevent_req_post(req, ev);
+
+ return req;
+}
+
+static errno_t resolv_discover_srv_next_domain(struct tevent_req *req)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *subreq = NULL;
+ const char *domain = NULL;
+ char *query = NULL;
+ errno_t ret;
+
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ domain = state->discovery_domains[state->domain_index];
+ if (domain == NULL) {
+ ret = EOK;
+ goto done;
+ }
+
+ query = talloc_asprintf(state, "_%s._%s.%s", state->service,
+ state->protocol, domain);
+ if (query == NULL) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ DEBUG(SSSDBG_TRACE_FUNC, ("SRV resolution of service '%s'. Will use DNS "
+ "discovery domain '%s'\n", state->service, domain));
+
+ subreq = resolv_getsrv_send(state, state->ev,
+ state->resolv_ctx, query);
+ if (subreq == NULL) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ tevent_req_set_callback(subreq, resolv_discover_srv_done, req);
+
+ state->domain_index++;
+ ret = EAGAIN;
+
+done:
+ if (ret != EAGAIN) {
+ talloc_free(query);
+ }
+
+ return ret;
+}
+
+static void resolv_discover_srv_done(struct tevent_req *subreq)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *req = NULL;
+ int status;
+ errno_t ret;
+
+ req = tevent_req_callback_data(subreq, struct tevent_req);
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ ret = resolv_getsrv_recv(state, subreq, &status, NULL, &state->reply_list);
+ talloc_zfree(subreq);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_OP_FAILURE, ("SRV query failed [%d]: %s\n",
+ status, resolv_strerror(status)));
+
+ if (status == ARES_ENOTFOUND) {
+ /* continue with next discovery domain */
+ ret = resolv_discover_srv_next_domain(req);
+ if (ret == EOK) {
+ /* there are no more domains to try */
+ ret = ENOENT;
+ }
+
+ goto done;
+ }
+
+ /* critical error when fetching SRV record */
+ ret = EIO;
+ goto done;
+ }
+
+done:
+ if (ret == EOK) {
+ tevent_req_done(req);
+ } else if (ret != EAGAIN) {
+ tevent_req_error(req, ret);
+ }
+
+ return;
+}
+
+errno_t resolv_discover_srv_recv(TALLOC_CTX *mem_ctx,
+ struct tevent_req *req,
+ struct ares_srv_reply **_reply_list,
+ char **_dns_domain)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ char *domain = NULL;
+
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ TEVENT_REQ_RETURN_ON_ERROR(req);
+
+ if (_dns_domain != NULL) {
+ /* domain_index now points to selected domain + 1 */
+ domain = talloc_strdup(mem_ctx,
+ state->discovery_domains[state->domain_index - 1]);
+ if (domain == NULL) {
+ return ENOMEM;
+ }
+
+ *_dns_domain = domain;
+ }
+
+ if (_reply_list != NULL) {
+ *_reply_list = talloc_steal(mem_ctx, state->reply_list);
+ }
+
+ return EOK;
+}