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/*
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_common(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_common(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_common(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_common(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_common(err));
return;
}
state->message[len-1] = '\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;
}
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