path: root/lib/tsocket/tsocket_sendto.c

/*
   Unix SMB/CIFS implementation.

   Copyright (C) Stefan Metzmacher 2009

     ** NOTE! The following LGPL license applies to the tevent
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include "system/network.h"
#include "tsocket.h"
#include "tsocket_internal.h"

struct tsocket_sendto_state {
	/* this structs are owned by the caller */
	struct {
		struct tsocket_context *sock;
		const uint8_t *buf;
		size_t len;
		const struct tsocket_address *dst;
	} caller;

	ssize_t ret;
};

static int tsocket_sendto_state_destructor(struct tsocket_sendto_state *state)
{
	if (state->caller.sock) {
		tsocket_set_writeable_handler(state->caller.sock, NULL, NULL);
	}
	ZERO_STRUCT(state->caller);

	return 0;
}

static void tsocket_sendto_handler(struct tsocket_context *sock,
				   void *private_data);

struct tevent_req *tsocket_sendto_send(struct tsocket_context *sock,
				       TALLOC_CTX *mem_ctx,
				       const uint8_t *buf,
				       size_t len,
				       const struct tsocket_address *dst)
{
	struct tevent_req *req;
	struct tsocket_sendto_state *state;
	int ret;
	int err;
	bool dummy;

	req = tevent_req_create(mem_ctx, &state,
				struct tsocket_sendto_state);
	if (!req) {
		return NULL;
	}

	state->caller.sock	= sock;
	state->caller.buf	= buf;
	state->caller.len	= len;
	state->caller.dst	= dst;
	state->ret		= -1;

	/*
	 * this is a fast path, not waiting for the
	 * socket to become explicit writeable gains
	 * about 10%-20% performance in benchmark tests.
	 */
	tsocket_sendto_handler(sock, req);
	if (!tevent_req_is_in_progress(req)) {
		goto post;
	}

	talloc_set_destructor(state, tsocket_sendto_state_destructor);

	ret = tsocket_set_writeable_handler(sock,
					    tsocket_sendto_handler,
					    req);
	err = tsocket_error_from_errno(ret, errno, &dummy);
	if (tevent_req_error(req, err)) {
		goto post;
	}

	return req;

 post:
	return tevent_req_post(req, sock->event.ctx);
}

static void tsocket_sendto_handler(struct tsocket_context *sock,
				   void *private_data)
{
	struct tevent_req *req = talloc_get_type(private_data,
				 struct tevent_req);
	struct tsocket_sendto_state *state = tevent_req_data(req,
					     struct tsocket_sendto_state);
	ssize_t ret;
	int err;
	bool retry;

	ret = tsocket_sendto(state->caller.sock,
			     state->caller.buf,
			     state->caller.len,
			     state->caller.dst);
	err = tsocket_error_from_errno(ret, errno, &retry);
	if (retry) {
		/* retry later */
		return;
	}
	if (tevent_req_error(req, err)) {
		return;
	}

	state->ret = ret;

	tevent_req_done(req);
}

ssize_t tsocket_sendto_recv(struct tevent_req *req, int *perrno)
{
	struct tsocket_sendto_state *state = tevent_req_data(req,
					     struct tsocket_sendto_state);
	ssize_t ret;

	ret = tsocket_simple_int_recv(req, perrno);
	if (ret == 0) {
		ret = state->ret;
	}

	tevent_req_received(req);
	return ret;
}

struct tsocket_sendto_queue_state {
	/* this structs are owned by the caller */
	struct {
		struct tsocket_context *sock;
		const uint8_t *buf;
		size_t len;
		const struct tsocket_address *dst;
	} caller;
	ssize_t ret;
};

static void tsocket_sendto_queue_trigger(struct tevent_req *req,
					 void *private_data);
static void tsocket_sendto_queue_done(struct tevent_req *subreq);

/**
 * @brief Queue a dgram blob for sending through the socket
 * @param[in] mem_ctx	The memory context for the result
 * @param[in] sock	The socket to send the message buffer
 * @param[in] queue	The existing dgram queue
 * @param[in] buf	The message buffer
 * @param[in] len	The message length
 * @param[in] dst	The destination socket address
 * @retval		The async request handle
 *
 * This function queues a blob for sending to destination through an existing
 * dgram socket. The async callback is triggered when the whole blob is
 * delivered to the underlying system socket.
 *
 * The caller needs to make sure that all non-scalar input parameters hang
 * arround for the whole lifetime of the request.
 */
struct tevent_req *tsocket_sendto_queue_send(TALLOC_CTX *mem_ctx,
					     struct tsocket_context *sock,
					     struct tevent_queue *queue,
					     const uint8_t *buf,
					     size_t len,
					     struct tsocket_address *dst)
{
	struct tevent_req *req;
	struct tsocket_sendto_queue_state *state;
	bool ok;

	req = tevent_req_create(mem_ctx, &state,
				struct tsocket_sendto_queue_state);
	if (!req) {
		return NULL;
	}

	state->caller.sock	= sock;
	state->caller.buf	= buf;
	state->caller.len	= len;
	state->caller.dst	= dst;
	state->ret		= -1;

	ok = tevent_queue_add(queue,
			      sock->event.ctx,
			      req,
			      tsocket_sendto_queue_trigger,
			      NULL);
	if (!ok) {
		tevent_req_nomem(NULL, req);
		goto post;
	}

	return req;

 post:
	return tevent_req_post(req, sock->event.ctx);
}

static void tsocket_sendto_queue_trigger(struct tevent_req *req,
					 void *private_data)
{
	struct tsocket_sendto_queue_state *state = tevent_req_data(req,
					struct tsocket_sendto_queue_state);
	struct tevent_req *subreq;

	subreq = tsocket_sendto_send(state->caller.sock,
				     state,
				     state->caller.buf,
				     state->caller.len,
				     state->caller.dst);
	if (tevent_req_nomem(subreq, req)) {
		return;
	}
	tevent_req_set_callback(subreq, tsocket_sendto_queue_done ,req);
}

static void tsocket_sendto_queue_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(subreq,
				 struct tevent_req);
	struct tsocket_sendto_queue_state *state = tevent_req_data(req,
					struct tsocket_sendto_queue_state);
	ssize_t ret;
	int sys_errno;

	ret = tsocket_sendto_recv(subreq, &sys_errno);
	talloc_free(subreq);
	if (ret == -1) {
		tevent_req_error(req, sys_errno);
		return;
	}
	state->ret = ret;

	tevent_req_done(req);
}

ssize_t tsocket_sendto_queue_recv(struct tevent_req *req, int *perrno)
{
	struct tsocket_sendto_queue_state *state = tevent_req_data(req,
					struct tsocket_sendto_queue_state);
	ssize_t ret;

	ret = tsocket_simple_int_recv(req, perrno);
	if (ret == 0) {
		ret = state->ret;
	}

	tevent_req_received(req);
	return ret;
}