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Diffstat (limited to 'libcli/echo/echo.c')
| -rw-r--r-- | libcli/echo/echo.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/libcli/echo/echo.c b/libcli/echo/echo.c new file mode 100644 index 0000000..0f5f7f7 --- /dev/null +++ b/libcli/echo/echo.c @@ -0,0 +1,209 @@ +/* + 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; + } + + if (len != state->orig_len) { + tevent_req_nterror(req, NT_STATUS_INVALID_NETWORK_RESPONSE); + 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; +} |