/*

 * Copyright (c) 2001-2020 Mellanox Technologies, Ltd. All rights reserved.

 *

 * This software is available to you under a choice of one of two

 * licenses.  You may choose to be licensed under the terms of the GNU

 * General Public License (GPL) Version 2, available from the file

 * COPYING in the main directory of this source tree, or the

 * BSD license below:

 *

 *     Redistribution and use in source and binary forms, with or

 *     without modification, are permitted provided that the following

 *     conditions are met:

 *

 *      - Redistributions of source code must retain the above

 *        copyright notice, this list of conditions and the following

 *        disclaimer.

 *

 *      - Redistributions in binary form must reproduce the above

 *        copyright notice, this list of conditions and the following

 *        disclaimer in the documentation and/or other materials

 *        provided with the distribution.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

#include "select_call.h"

#include "utils/bullseye.h"

#include "vlogger/vlogger.h"

#include <vma/util/vtypes.h>

#include <vma/sock/sock-redirect.h>

#include <vma/sock/fd_collection.h>

#include <vma/dev/net_device_table_mgr.h>

#define MODULE_NAME "select_call:"

#define FD_COPY(__fddst, __fdsrc, __nfds) \

		memcpy(__FDS_BITS(__fddst), __FDS_BITS(__fdsrc), ((__nfds) + 7) >> 3)

#undef  FD_ZERO // Remove select.h origianl FD_ZERO and define our own with limit size

#define FD_ZERO(__fddst, __nfds) \

		memset(__FDS_BITS(__fddst), 0, ((__nfds) + 7) >> 3)

iomux_func_stats_t g_select_stats;

select_call::select_call(int *off_fds_buffer, offloaded_mode_t *off_modes_buffer,

                         int nfds, fd_set *readfds, fd_set *writefds,

                         fd_set *exceptfds, timeval *timeout, const sigset_t *__sigmask /* = NULL */) :

	io_mux_call(off_fds_buffer, off_modes_buffer, nfds, __sigmask),

	m_nfds(nfds), m_readfds(readfds), m_writefds(writefds),

	m_exceptfds(exceptfds), m_timeout(timeout), m_nfds_with_cq(0), m_b_run_prepare_to_poll(false)

{

	int fd;

	//socket_fd_api* temp_sock_fd_api = NULL; 

	if (m_nfds > FD_SETSIZE) {

		errno = ENOMEM;

		vma_throw_object(io_mux_call::io_error);

	}

	// create stats

	m_p_stats = &g_select_stats;

        vma_stats_instance_get_select_block(m_p_stats);

	bool offloaded_read  = !!m_readfds;

	bool offloaded_write = !!m_writefds;

	if (offloaded_read || offloaded_write) {

		FD_ZERO(&m_os_rfds, m_nfds);

		FD_ZERO(&m_os_wfds, m_nfds);

		//covers the case of select(readfds = NULL)

		if(!m_readfds) {

			FD_ZERO(&m_cq_rfds, m_nfds);

			m_readfds = &m_cq_rfds;

		}

		// get offloaded fds in read set

		for (fd = 0; fd < m_nfds; ++fd) {

			bool check_read = offloaded_read && FD_ISSET(fd, m_readfds);

			bool check_write = offloaded_write && FD_ISSET(fd, m_writefds);

			socket_fd_api* psock = fd_collection_get_sockfd(fd);

			if (psock && psock->get_type() == FD_TYPE_SOCKET) {

				offloaded_mode_t off_mode  = OFF_NONE;

				if (check_read)  off_mode = (offloaded_mode_t)(off_mode | OFF_READ);

				if (check_write) off_mode = (offloaded_mode_t)(off_mode | OFF_WRITE);

				if (off_mode) {

					__log_func("---> fd=%d IS SET for read or write!", fd);

					m_p_all_offloaded_fds[m_num_all_offloaded_fds] = fd;

					m_p_offloaded_modes[m_num_all_offloaded_fds] = off_mode;

					m_num_all_offloaded_fds++;

					if (! psock->skip_os_select()) {

						if (check_read) {

							FD_SET(fd, &m_os_rfds);

							if (psock->is_readable(NULL)) {

								io_mux_call::update_fd_array(&m_fd_ready_array, fd);

								m_n_ready_rfds++;

								m_n_all_ready_fds++;

							} else {

								// Instructing the socket to sample the OS immediately to prevent hitting EAGAIN on recvfrom(),

								// after iomux returned a shadow fd as ready (only for non-blocking sockets)

								psock->set_immediate_os_sample();

							}

						}

						if (check_write) {

							FD_SET(fd, &m_os_wfds);

						}

					}

					else

						__log_func("fd=%d must be skipped from os r select()", fd);

				}

			}

                        else {

                                if (check_read)  {

                                        FD_SET(fd, &m_os_rfds);

                                }

                                if (check_write) {

                                        FD_SET(fd, &m_os_wfds);

                                }

                        }

		}

	}

	__log_func("num all offloaded_fds=%d", m_num_all_offloaded_fds);

}

void select_call::prepare_to_poll()

{

	/* 

	 * Create copies of all sets and zero out the originals.

	 * This is needed because polling might be successful.

	 * 

	 * If the read set is zero, use the local copy every time.

	 * This is OK because it will hold only the CQ, and wait()

	 * clears the CQ from the set after orig_select() call.

	 * 

	 * m_readfds is non-NULL here because there are offloaded sockets.

	 */

	// copy sets, and zero out the originals

	if (m_readfds) {

		FD_COPY(&m_orig_readfds, m_readfds, m_nfds);

		FD_ZERO(m_readfds, m_nfds);

	}

	if (m_writefds) {

		FD_COPY(&m_orig_writefds, m_writefds, m_nfds);

		FD_ZERO(m_writefds, m_nfds);

	}

	if (m_exceptfds) {

		FD_COPY(&m_orig_exceptfds, m_exceptfds, m_nfds);

		FD_ZERO(m_exceptfds, m_nfds);

	}

	m_b_run_prepare_to_poll = true;

}

void select_call::prepare_to_block()

{

	m_cqepfd = g_p_net_device_table_mgr->global_ring_epfd_get();

	m_nfds_with_cq = max(m_cqepfd + 1, m_nfds);

}

bool select_call::wait_os(bool zero_timeout)

{

	timeval to, *pto = NULL;

	timespec to_pselect, *pto_pselect = NULL;

/* Avner: I put it in comment, because this logic is wrong

	// optimization: do not call os select if ALL fds are excluded

	// extend check to write/except fds

	if (m_rfd_count == m_n_exclude_fds)

		return;

*/

	if (zero_timeout) {

		to.tv_sec = to.tv_usec = 0;

		pto = &to;

	}

	else {

		pto = m_timeout;

	}

	// Restore original sets

	if (m_b_run_prepare_to_poll) {

		if (m_readfds)	FD_COPY(m_readfds, &m_os_rfds, m_nfds);

		if (m_writefds)	FD_COPY(m_writefds, &m_os_wfds, m_nfds);

		if (m_exceptfds)FD_COPY(m_exceptfds, &m_orig_exceptfds, m_nfds);

	}

	__log_func("calling os select: %d", m_nfds);

	if (m_sigmask) {

		if (pto) {

			to_pselect.tv_sec = pto->tv_sec;

			to_pselect.tv_nsec = pto->tv_usec * 1000;

			pto_pselect = &to_pselect;

		}

		m_n_all_ready_fds = orig_os_api.pselect(m_nfds, m_readfds, m_writefds, m_exceptfds, pto_pselect, m_sigmask);

	} else {

		m_n_all_ready_fds = orig_os_api.select(m_nfds, m_readfds, m_writefds, m_exceptfds, pto);

	}

	if (m_n_all_ready_fds < 0) {

		vma_throw_object(io_mux_call::io_error);

	}

	if (m_n_all_ready_fds > 0) {

		__log_func("wait_os() returned with %d", m_n_all_ready_fds);

	}

	return false; // No cq_fd in select() event

}

bool select_call::wait(const timeval &elapsed)

{

	timeval timeout, *pto = NULL;

	timespec to_pselect, *pto_pselect = NULL;

	BULLSEYE_EXCLUDE_BLOCK_START

	if (m_n_all_ready_fds > 0) {

		__log_panic("wait() called when there are ready fd's!!!");

		// YossiE TODO make this and some more checks as debug assertions

		// In all functions

	}

	BULLSEYE_EXCLUDE_BLOCK_END

	// Restore original sets

	if (m_b_run_prepare_to_poll) {

		if (m_readfds)	FD_COPY(m_readfds, &m_os_rfds, m_nfds);

		if (m_writefds)	FD_COPY(m_writefds, &m_os_wfds, m_nfds);

		if (m_exceptfds)FD_COPY(m_exceptfds, &m_orig_exceptfds, m_nfds);

	}

	// Call OS select() on original sets + CQ epfd in read set

	if (m_readfds)

		FD_SET(m_cqepfd, m_readfds);

	if (m_timeout) {

		tv_sub(m_timeout, &elapsed, &timeout);

		if (timeout.tv_sec < 0 || timeout.tv_usec < 0) {

			// Already reached timeout

			return false;

		}

		pto = &timeout;

	}

	__log_func("going to wait on select CQ+OS nfds=%d cqfd=%d pto=%p!!!", m_nfds_with_cq, m_cqepfd, pto);

	// ACTUAL CALL TO SELECT

	if (m_sigmask) {

		if (pto) {

			to_pselect.tv_sec = pto->tv_sec;

			to_pselect.tv_nsec = pto->tv_usec * 1000;

			pto_pselect = &to_pselect;

		}

		m_n_all_ready_fds = orig_os_api.pselect(m_nfds, m_readfds, m_writefds, m_exceptfds, pto_pselect, m_sigmask);

	} else {

		m_n_all_ready_fds = orig_os_api.select(m_nfds_with_cq, m_readfds, m_writefds, m_exceptfds, pto);

	}

	__log_func("done select CQ+OS nfds=%d cqfd=%d pto=%p ready=%d!!!", m_nfds_with_cq, m_cqepfd, pto, m_n_all_ready_fds);

	if (m_n_all_ready_fds < 0) {

		vma_throw_object(io_mux_call::io_error);

	}

	// Clear CQ from the set and don't count it

	if (m_readfds)

	{

		if (FD_ISSET(m_cqepfd, m_readfds)) {

			FD_CLR(m_cqepfd, m_readfds); // Not needed if m_readfds is NULL

			--m_n_all_ready_fds;

			return true;

		}

	}

	return false;

}

bool select_call::is_timeout(const timeval &elapsed)

{

	return m_timeout && tv_cmp(m_timeout, &elapsed, <=);

}

void select_call::set_offloaded_rfd_ready(int fd_index)

{

	if (m_p_offloaded_modes[fd_index] & OFF_READ) { //TODO: consider removing

		int fd = m_p_all_offloaded_fds[fd_index];

		if (!FD_ISSET(fd, m_readfds)) {

			FD_SET(fd, m_readfds);

			++m_n_ready_rfds;

			++m_n_all_ready_fds;

			__log_func("ready offloaded fd: %d", fd);

		}

	}

}

void select_call::set_rfd_ready(int fd)

{

	// This function also checks that fd was in the original read set

	if (!FD_ISSET(fd, m_readfds) && FD_ISSET(fd, &m_orig_readfds)) {

		FD_SET(fd, m_readfds);

		++m_n_ready_rfds;

//		if (!FD_ISSET(fd, m_writefds))

		++m_n_all_ready_fds;

	}

}

void select_call::set_offloaded_wfd_ready(int fd_index)

{

	if (m_p_offloaded_modes[fd_index] & OFF_WRITE) { //TODO: consider removing

		int fd = m_p_all_offloaded_fds[fd_index];

		if (!FD_ISSET(fd, m_writefds)) {

			FD_SET(fd, m_writefds);

			++m_n_ready_wfds;

			++m_n_all_ready_fds;

			__log_func("ready offloaded w fd: %d", fd);

		}

	}

}

void select_call::set_wfd_ready(int fd)

{

	// This function also checks that fd was in the original read set

	if (!FD_ISSET(fd, m_writefds) && FD_ISSET(fd, &m_orig_writefds)) { //TODO: why do we need the last 'if'??

		FD_SET(fd, m_writefds);

		++m_n_ready_wfds;

//		if (!FD_ISSET(fd, m_readfds))

		++m_n_all_ready_fds;

		__log_func("ready w fd: %d", fd);

	}

}

void select_call::set_efd_ready(int fd, int errors)

{

	/* TODO currently consider errors as ready to write OR read */

	NOT_IN_USE(errors);

	NOT_IN_USE(fd);

}