1 files changed, 204 insertions, 0 deletions
diff --git a/libcli/echo/echo.c b/libcli/echo/echo.c
new file mode 100644
index 0000000000..46d1e28b36
--- /dev/null
+++ b/libcli/echo/echo.c
@@ -0,0 +1,204 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Echo example async client library
+
+   Copyright (C) 2010 Kai Blin  <kai@samba.org>
+
+   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 "replace.h"
+#include "system/network.h"
+#include <tevent.h>
+#include "lib/tsocket/tsocket.h"
+#include "libcli/util/ntstatus.h"
+#include "libcli/echo/libecho.h"
+#include "lib/util/tevent_ntstatus.h"
+#include "libcli/util/error.h"
+
+/*
+ * Following the Samba convention for async functions, set up a state struct
+ * for this set of calls. The state is always called function_name_state for
+ * the set of async functions related to function_name_send().
+ */
+struct echo_request_state {
+	struct tevent_context *ev;
+	ssize_t orig_len;
+	struct tdgram_context *dgram;
+	char *message;
+};
+
+/* Declare callback functions used below. */
+static void echo_request_get_reply(struct tevent_req *subreq);
+static void echo_request_done(struct tevent_req *subreq);
+
+struct tevent_req *echo_request_send(TALLOC_CTX *mem_ctx,
+				     struct tevent_context *ev,
+				     const char *server_addr_string,
+				     const char *message)
+{
+	struct tevent_req *req, *subreq;
+	struct echo_request_state *state;
+	struct tsocket_address *local_addr, *server_addr;
+	struct tdgram_context *dgram;
+	int ret;
+
+	/*
+	 * Creating the initial tevent_req is the only place where returning
+	 * NULL is allowed. Everything after that should return a more
+	 * meaningful error using tevent_req_post().
+	 */
+	req = tevent_req_create(mem_ctx, &state, struct echo_request_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	/*
+	 * We need to dispatch new async functions in the callbacks, hold
+	 * on to the event context.
+	 */
+	state->ev = ev;
+
+	/* libecho uses connected UDP sockets, take care of this here */
+	ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0,
+						&local_addr);
+	if (ret != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return tevent_req_post(req, ev);
+	}
+
+	ret = tsocket_address_inet_from_strings(state, "ip", server_addr_string,
+						ECHO_PORT, &server_addr);
+	if (ret != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return tevent_req_post(req, ev);
+	}
+
+	ret = tdgram_inet_udp_socket(local_addr, server_addr, state, &dgram);
+	if (ret != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(ret));
+		return tevent_req_post(req, ev);
+	}
+
+	state->dgram = dgram;
+	state->orig_len = strlen(message) + 1;
+
+	/* Start of a subrequest for the actual data sending */
+	subreq = tdgram_sendto_send(state, ev, dgram,
+				    (const uint8_t *) message,
+				    state->orig_len, NULL);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	/*
+	 * And tell tevent what to call when the subreq is done. Note that the
+	 * original req structure is passed into the callback as callback data.
+	 * This is used to get to the state struct in callbacks.
+	 */
+	tevent_req_set_callback(subreq, echo_request_get_reply, req);
+	return req;
+}
+
+/*
+ * The following two callbacks both demonstrate the way of getting back the
+ * state struct in a callback function.
+ */
+
+static void echo_request_get_reply(struct tevent_req *subreq)
+{
+	/* Get the parent request struct from the callback data */
+	struct tevent_req *req = tevent_req_callback_data(subreq,
+						struct tevent_req);
+	/* And get the state struct from the parent request struct */
+	struct echo_request_state *state = tevent_req_data(req,
+						struct echo_request_state);
+	ssize_t len;
+	int err = 0;
+
+	len = tdgram_sendto_recv(subreq, &err);
+	TALLOC_FREE(subreq);
+
+	if (len == -1 && err != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(err));
+		return;
+	}
+
+	if (len != state->orig_len) {
+		tevent_req_nterror(req, NT_STATUS_UNEXPECTED_NETWORK_ERROR);
+		return;
+	}
+
+	/* Send off the second subreq here, this time to receive the reply */
+	subreq = tdgram_recvfrom_send(state, state->ev, state->dgram);
+	if (tevent_req_nomem(subreq, req)) {
+		return;
+	}
+
+	/* And set the new callback */
+	tevent_req_set_callback(subreq, echo_request_done, req);
+	return;
+}
+
+static void echo_request_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(subreq,
+						struct tevent_req);
+	struct echo_request_state *state = tevent_req_data(req,
+						struct echo_request_state);
+
+	ssize_t len;
+	int err = 0;
+
+	len = tdgram_recvfrom_recv(subreq, &err, state,
+				   (uint8_t **)&state->message,
+				   NULL);
+	TALLOC_FREE(subreq);
+
+	if (len == -1 && err != 0) {
+		tevent_req_nterror(req, map_nt_error_from_unix(err));
+		return;
+	}
+
+	state->message[len] = '\0';
+	/* Once the async function has completed, set tevent_req_done() */
+	tevent_req_done(req);
+}
+
+/*
+ * In the recv function, we usually need to move the data from the state struct
+ * to the memory area owned by the caller. Also, the function
+ * tevent_req_received() is called to take care of freeing the memory still
+ * associated with the request.
+ */
+
+NTSTATUS echo_request_recv(struct tevent_req *req,
+			   TALLOC_CTX *mem_ctx,
+			   char **message)
+{
+	struct echo_request_state *state = tevent_req_data(req,
+			struct echo_request_state);
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		tevent_req_received(req);
+		return status;
+	}
+
+	*message = talloc_move(mem_ctx, &state->message);
+	tevent_req_received(req);
+
+	return NT_STATUS_OK;
+}