s3: Add wbinfo --dc-info

wbinfo --dc-info prints the current DC name and IP address. This helps
diagnosing problems that might happen when a later wbinfo --ping-dc fails.

This patch started out by using the SAF and NBT cache entires, but those are
relatively short-lived. So I decided to invent a new gencache entry with a very
long timeout. We need to go via the gencache because when for some reason a
winbind child process is stuck, we can't query it for the current DC it's
connected to. This must eventually go away again when we have a fully async
winbind.

Autobuild-User: Volker Lendecke <vlendec@samba.org>
Autobuild-Date: Wed Jan 19 08:40:28 CET 2011 on sn-devel-104

4 files changed, 148 insertions, 0 deletions

diff --git a/source3/winbindd/winbindd.c b/source3/winbindd/winbindd.c
index e5aeca68304..8f4a205db5a 100644
--- a/source3/winbindd/winbindd.c
+++ b/source3/winbindd/winbindd.c
@@ -442,6 +442,7 @@ static struct winbindd_dispatch_table {
 	  "INTERFACE_VERSION" },
 	{ WINBINDD_DOMAIN_NAME, winbindd_domain_name, "DOMAIN_NAME" },
 	{ WINBINDD_DOMAIN_INFO, winbindd_domain_info, "DOMAIN_INFO" },
+	{ WINBINDD_DC_INFO, winbindd_dc_info, "DC_INFO" },
 	{ WINBINDD_NETBIOS_NAME, winbindd_netbios_name, "NETBIOS_NAME" },
 	{ WINBINDD_PRIV_PIPE_DIR, winbindd_priv_pipe_dir,
 	  "WINBINDD_PRIV_PIPE_DIR" },
diff --git a/source3/winbindd/winbindd_cm.c b/source3/winbindd/winbindd_cm.c
index b36f79fb3c7..8e29b7d5843 100644
--- a/source3/winbindd/winbindd_cm.c
+++ b/source3/winbindd/winbindd_cm.c
@@ -1419,6 +1419,88 @@ static bool find_new_dc(TALLOC_CTX *mem_ctx,
 	goto again;
 }
 
+static char *current_dc_key(TALLOC_CTX *mem_ctx, const char *domain_name)
+{
+	return talloc_asprintf_strupper_m(mem_ctx, "CURRENT_DCNAME/%s",
+					  domain_name);
+}
+
+static void store_current_dc_in_gencache(const char *domain_name,
+					 const char *dc_name,
+					 struct cli_state *cli)
+{
+	char addr[INET6_ADDRSTRLEN];
+	char *key, *value;
+
+	if (cli == NULL) {
+		return;
+	}
+	if (cli->fd == -1) {
+		return;
+	}
+	get_peer_addr(cli->fd, addr, sizeof(addr));
+
+	key = current_dc_key(talloc_tos(), domain_name);
+	if (key == NULL) {
+		goto done;
+	}
+
+	value = talloc_asprintf(talloc_tos(), "%s %s", addr, dc_name);
+	if (value == NULL) {
+		goto done;
+	}
+
+	gencache_set(key, value, 0x7ffffffff);
+done:
+	TALLOC_FREE(value);
+	TALLOC_FREE(key);
+}
+
+bool fetch_current_dc_from_gencache(TALLOC_CTX *mem_ctx,
+				    const char *domain_name,
+				    char **p_dc_name, char **p_dc_ip)
+{
+	char *key, *value, *p;
+	bool ret = false;
+	char *dc_name = NULL;
+	char *dc_ip = NULL;
+
+	key = current_dc_key(talloc_tos(), domain_name);
+	if (key == NULL) {
+		goto done;
+	}
+	if (!gencache_get(key, &value, NULL)) {
+		goto done;
+	}
+	p = strchr(value, ' ');
+	if (p == NULL) {
+		goto done;
+	}
+	dc_ip = talloc_strndup(mem_ctx, value, p - value);
+	if (dc_ip == NULL) {
+		goto done;
+	}
+	dc_name = talloc_strdup(mem_ctx, p+1);
+	if (dc_name == NULL) {
+		goto done;
+	}
+
+	if (p_dc_ip != NULL) {
+		*p_dc_ip = dc_ip;
+		dc_ip = NULL;
+	}
+	if (p_dc_name != NULL) {
+		*p_dc_name = dc_name;
+		dc_name = NULL;
+	}
+	ret = true;
+done:
+	TALLOC_FREE(dc_name);
+	TALLOC_FREE(dc_ip);
+	TALLOC_FREE(key);
+	return ret;
+}
+
 static NTSTATUS cm_open_connection(struct winbindd_domain *domain,
 				   struct winbindd_cm_conn *new_conn)
 {
@@ -1520,6 +1602,17 @@ static NTSTATUS cm_open_connection(struct winbindd_domain *domain,
 			set_global_winbindd_state_online();
 		}
 		set_domain_online(domain);
+
+		/*
+		 * Much as I hate global state, this seems to be the point
+		 * where we can be certain that we have a proper connection to
+		 * a DC. wbinfo --dc-info needs that information, store it in
+		 * gencache with a looong timeout. This will need revisiting
+		 * once we start to connect to multiple DCs, wbcDcInfo is
+		 * already prepared for that.
+		 */
+		store_current_dc_in_gencache(domain->name, domain->dcname,
+					     new_conn->cli);
 	} else {
 		/* Ensure we setup the retry handler. */
 		set_domain_offline(domain);
diff --git a/source3/winbindd/winbindd_misc.c b/source3/winbindd/winbindd_misc.c
index caf213b5511..42ecea2aad7 100644
--- a/source3/winbindd/winbindd_misc.c
+++ b/source3/winbindd/winbindd_misc.c
@@ -314,6 +314,56 @@ static void domain_info_done(struct tevent_req *req)
 	request_ok(state->cli);
 }
 
+void winbindd_dc_info(struct winbindd_cli_state *cli)
+{
+	struct winbindd_domain *domain;
+	char *dc_name, *dc_ip;
+
+	cli->request->domain_name[sizeof(cli->request->domain_name-1)] = '\0';
+
+	DEBUG(3, ("[%5lu]: domain_info [%s]\n", (unsigned long)cli->pid,
+		  cli->request->domain_name));
+
+	if (cli->request->domain_name[0] != '\0') {
+		domain = find_domain_from_name_noinit(
+			cli->request->domain_name);
+		DEBUG(10, ("Could not find domain %s\n",
+			   cli->request->domain_name));
+		if (domain == NULL) {
+			request_error(cli);
+			return;
+		}
+	} else {
+		domain = find_our_domain();
+	}
+
+	if (!fetch_current_dc_from_gencache(
+		    talloc_tos(), domain->name, &dc_name, &dc_ip)) {
+		DEBUG(10, ("fetch_current_dc_from_gencache(%s) failed\n",
+			   domain->name));
+		request_error(cli);
+		return;
+	}
+
+	cli->response->data.num_entries = 1;
+	cli->response->extra_data.data = talloc_asprintf(
+		cli->mem_ctx, "%s\n%s\n", dc_name, dc_ip);
+
+	TALLOC_FREE(dc_name);
+	TALLOC_FREE(dc_ip);
+
+	if (cli->response->extra_data.data == NULL) {
+		request_error(cli);
+		return;
+	}
+
+	/* must add one to length to copy the 0 for string termination */
+	cli->response->length +=
+		strlen((char *)cli->response->extra_data.data) + 1;
+
+	request_ok(cli);
+}
+
 /* List various tidbits of information */
 
 void winbindd_info(struct winbindd_cli_state *state)
diff --git a/source3/winbindd/winbindd_proto.h b/source3/winbindd/winbindd_proto.h
index dc563c9dac7..5cb6c4c1555 100644
--- a/source3/winbindd/winbindd_proto.h
+++ b/source3/winbindd/winbindd_proto.h
@@ -170,6 +170,9 @@ NTSTATUS cm_connect_lsa_tcp(struct winbindd_domain *domain,
 			    struct rpc_pipe_client **cli);
 NTSTATUS cm_connect_netlogon(struct winbindd_domain *domain,
 			     struct rpc_pipe_client **cli);
+bool fetch_current_dc_from_gencache(TALLOC_CTX *mem_ctx,
+				    const char *domain_name,
+				    char **p_dc_name, char **p_dc_ip);
 
 /* The following definitions come from winbindd/winbindd_cred_cache.c  */
 
@@ -322,6 +325,7 @@ enum winbindd_result winbindd_dual_list_trusted_domains(struct winbindd_domain *
 							struct winbindd_cli_state *state);
 void winbindd_show_sequence(struct winbindd_cli_state *state);
 void winbindd_domain_info(struct winbindd_cli_state *state);
+void winbindd_dc_info(struct winbindd_cli_state *state);
 void winbindd_ping(struct winbindd_cli_state *state);
 void winbindd_info(struct winbindd_cli_state *state);
 void winbindd_interface_version(struct winbindd_cli_state *state);