/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   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.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "event_nvmf.h"

#include "spdk/bdev.h"
#include "spdk/event.h"
#include "spdk/thread.h"
#include "spdk/log.h"
#include "spdk/nvme.h"
#include "spdk/util.h"

enum nvmf_tgt_state {
	NVMF_TGT_INIT_NONE = 0,
	NVMF_TGT_INIT_PARSE_CONFIG,
	NVMF_TGT_INIT_CREATE_POLL_GROUPS,
	NVMF_TGT_INIT_START_SUBSYSTEMS,
	NVMF_TGT_INIT_START_ACCEPTOR,
	NVMF_TGT_RUNNING,
	NVMF_TGT_FINI_STOP_SUBSYSTEMS,
	NVMF_TGT_FINI_DESTROY_POLL_GROUPS,
	NVMF_TGT_FINI_STOP_ACCEPTOR,
	NVMF_TGT_FINI_FREE_RESOURCES,
	NVMF_TGT_STOPPED,
	NVMF_TGT_ERROR,
};

struct nvmf_tgt_poll_group {
	struct spdk_nvmf_poll_group		*group;
	struct spdk_thread			*thread;
	TAILQ_ENTRY(nvmf_tgt_poll_group)	link;
};

struct nvmf_tgt_host_trid {
	struct spdk_nvme_transport_id       host_trid;
	struct nvmf_tgt_poll_group          *pg;
	uint32_t                            ref;
	TAILQ_ENTRY(nvmf_tgt_host_trid)     link;
};

/* List of host trids that are connected to the target */
static TAILQ_HEAD(, nvmf_tgt_host_trid) g_nvmf_tgt_host_trids =
	TAILQ_HEAD_INITIALIZER(g_nvmf_tgt_host_trids);

struct spdk_nvmf_tgt *g_spdk_nvmf_tgt = NULL;

static enum nvmf_tgt_state g_tgt_state;

/* Round-Robin/IP-based tracking of threads to poll group assignment */
static struct nvmf_tgt_poll_group *g_next_poll_group = NULL;

static TAILQ_HEAD(, nvmf_tgt_poll_group) g_poll_groups = TAILQ_HEAD_INITIALIZER(g_poll_groups);
static size_t g_num_poll_groups = 0;

static struct spdk_poller *g_acceptor_poller = NULL;

static void nvmf_tgt_advance_state(void);

static void
_spdk_nvmf_shutdown_cb(void *arg1)
{
	/* Still in initialization state, defer shutdown operation */
	if (g_tgt_state < NVMF_TGT_RUNNING) {
		spdk_thread_send_msg(spdk_get_thread(), _spdk_nvmf_shutdown_cb, NULL);
		return;
	} else if (g_tgt_state > NVMF_TGT_RUNNING) {
		/* Already in Shutdown status, ignore the signal */
		return;
	}

	g_tgt_state = NVMF_TGT_FINI_STOP_SUBSYSTEMS;
	nvmf_tgt_advance_state();
}

static void
spdk_nvmf_subsystem_fini(void)
{
	_spdk_nvmf_shutdown_cb(NULL);
}

/* Round robin selection of poll groups */
static struct nvmf_tgt_poll_group *
spdk_nvmf_get_next_pg(void)
{
	struct nvmf_tgt_poll_group *pg;

	pg = g_next_poll_group;
	g_next_poll_group = TAILQ_NEXT(pg, link);
	if (g_next_poll_group == NULL) {
		g_next_poll_group = TAILQ_FIRST(&g_poll_groups);
	}

	return pg;
}

static struct nvmf_tgt_poll_group *
spdk_nvmf_get_optimal_pg(struct spdk_nvmf_qpair *qpair)
{
	struct nvmf_tgt_poll_group *pg, *_pg = NULL;
	struct spdk_nvmf_poll_group *group = spdk_nvmf_get_optimal_poll_group(qpair);

	if (group == NULL) {
		_pg = spdk_nvmf_get_next_pg();
		goto end;
	}

	TAILQ_FOREACH(pg, &g_poll_groups, link) {
		if (pg->group == group) {
			_pg = pg;
			break;
		}

	}

end:
	assert(_pg != NULL);
	return _pg;
}

static void
nvmf_tgt_remove_host_trid(struct spdk_nvmf_qpair *qpair)
{
	struct spdk_nvme_transport_id trid_to_remove;
	struct nvmf_tgt_host_trid *trid = NULL, *tmp_trid = NULL;

	if (g_spdk_nvmf_tgt_conf->conn_sched != CONNECT_SCHED_HOST_IP) {
		return;
	}

	if (spdk_nvmf_qpair_get_peer_trid(qpair, &trid_to_remove) != 0) {
		return;
	}

	TAILQ_FOREACH_SAFE(trid, &g_nvmf_tgt_host_trids, link, tmp_trid) {
		if (trid && !strncmp(trid->host_trid.traddr,
				     trid_to_remove.traddr, SPDK_NVMF_TRADDR_MAX_LEN + 1)) {
			trid->ref--;
			if (trid->ref == 0) {
				TAILQ_REMOVE(&g_nvmf_tgt_host_trids, trid, link);
				free(trid);
			}

			break;
		}
	}

	return;
}

static struct nvmf_tgt_poll_group *
nvmf_tgt_get_pg(struct spdk_nvmf_qpair *qpair)
{
	struct spdk_nvme_transport_id trid;
	struct nvmf_tgt_host_trid *tmp_trid = NULL, *new_trid = NULL;
	struct nvmf_tgt_poll_group *pg;
	int ret;

	switch (g_spdk_nvmf_tgt_conf->conn_sched) {
	case CONNECT_SCHED_HOST_IP:
		ret = spdk_nvmf_qpair_get_peer_trid(qpair, &trid);
		if (ret) {
			pg = g_next_poll_group;
			SPDK_ERRLOG("Invalid host transport Id. Assigning to poll group %p\n", pg);
			break;
		}

		TAILQ_FOREACH(tmp_trid, &g_nvmf_tgt_host_trids, link) {
			if (tmp_trid && !strncmp(tmp_trid->host_trid.traddr,
						 trid.traddr, SPDK_NVMF_TRADDR_MAX_LEN + 1)) {
				tmp_trid->ref++;
				pg = tmp_trid->pg;
				break;
			}
		}
		if (!tmp_trid) {
			new_trid = calloc(1, sizeof(*new_trid));
			if (!new_trid) {
				pg = g_next_poll_group;
				SPDK_ERRLOG("Insufficient memory. Assigning to poll group %p\n", pg);
				break;
			}
			/* Get the next available poll group for the new host */
			pg = spdk_nvmf_get_next_pg();
			new_trid->pg = pg;
			memcpy(new_trid->host_trid.traddr, trid.traddr,
			       SPDK_NVMF_TRADDR_MAX_LEN + 1);
			TAILQ_INSERT_TAIL(&g_nvmf_tgt_host_trids, new_trid, link);
		}
		break;
	case CONNECT_SCHED_TRANSPORT_OPTIMAL_GROUP:
		pg = spdk_nvmf_get_optimal_pg(qpair);
		break;
	case CONNECT_SCHED_ROUND_ROBIN:
	default:
		pg = spdk_nvmf_get_next_pg();
		break;
	}

	return pg;
}

struct nvmf_tgt_pg_ctx {
	struct spdk_nvmf_qpair *qpair;
	struct nvmf_tgt_poll_group *pg;
};

static void
nvmf_tgt_poll_group_add(void *_ctx)
{
	struct nvmf_tgt_pg_ctx *ctx = _ctx;
	struct spdk_nvmf_qpair *qpair = ctx->qpair;
	struct nvmf_tgt_poll_group *pg = ctx->pg;

	free(_ctx);

	if (spdk_nvmf_poll_group_add(pg->group, qpair) != 0) {
		SPDK_ERRLOG("Unable to add the qpair to a poll group.\n");
		spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
	}
}

static void
new_qpair(struct spdk_nvmf_qpair *qpair)
{
	struct nvmf_tgt_pg_ctx *ctx;
	struct nvmf_tgt_poll_group *pg;
	uint32_t attempts;

	if (g_tgt_state != NVMF_TGT_RUNNING) {
		spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
		return;
	}

	for (attempts = 0; attempts < g_num_poll_groups; attempts++) {
		pg = nvmf_tgt_get_pg(qpair);
		if (pg->group != NULL) {
			break;
		} else {
			nvmf_tgt_remove_host_trid(qpair);
		}
	}

	if (attempts == g_num_poll_groups) {
		SPDK_ERRLOG("No poll groups exist.\n");
		spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
		return;
	}

	ctx = calloc(1, sizeof(*ctx));
	if (!ctx) {
		SPDK_ERRLOG("Unable to send message to poll group.\n");
		spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
		return;
	}

	ctx->qpair = qpair;
	ctx->pg = pg;

	spdk_thread_send_msg(pg->thread, nvmf_tgt_poll_group_add, ctx);
}

static int
acceptor_poll(void *arg)
{
	struct spdk_nvmf_tgt *tgt = arg;

	spdk_nvmf_tgt_accept(tgt, new_qpair);

	return -1;
}

static void
nvmf_tgt_destroy_poll_group_done(void *ctx)
{
	g_tgt_state = NVMF_TGT_FINI_STOP_ACCEPTOR;
	assert(g_num_poll_groups == 0);
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_destroy_poll_group(void *ctx)
{
	struct nvmf_tgt_poll_group *pg, *tpg;
	struct spdk_thread *thread;

	thread = spdk_get_thread();

	TAILQ_FOREACH_SAFE(pg, &g_poll_groups, link, tpg) {
		if (pg->thread == thread) {
			TAILQ_REMOVE(&g_poll_groups, pg, link);
			spdk_nvmf_poll_group_destroy(pg->group);
			free(pg);
			assert(g_num_poll_groups > 0);
			g_num_poll_groups--;
			return;
		}
	}
}

static void
nvmf_tgt_create_poll_group_done(void *ctx)
{
	g_tgt_state = NVMF_TGT_INIT_START_SUBSYSTEMS;
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_create_poll_group(void *ctx)
{
	struct nvmf_tgt_poll_group *pg;

	pg = calloc(1, sizeof(*pg));
	if (!pg) {
		SPDK_ERRLOG("Not enough memory to allocate poll groups\n");
		spdk_app_stop(-ENOMEM);
		return;
	}

	pg->thread = spdk_get_thread();
	pg->group = spdk_nvmf_poll_group_create(g_spdk_nvmf_tgt);
	TAILQ_INSERT_TAIL(&g_poll_groups, pg, link);
	g_num_poll_groups++;

	if (g_next_poll_group == NULL) {
		g_next_poll_group = pg;
	}
}

static void
nvmf_tgt_subsystem_started(struct spdk_nvmf_subsystem *subsystem,
			   void *cb_arg, int status)
{
	subsystem = spdk_nvmf_subsystem_get_next(subsystem);

	if (subsystem) {
		spdk_nvmf_subsystem_start(subsystem, nvmf_tgt_subsystem_started, NULL);
		return;
	}

	g_tgt_state = NVMF_TGT_INIT_START_ACCEPTOR;
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_subsystem_stopped(struct spdk_nvmf_subsystem *subsystem,
			   void *cb_arg, int status)
{
	subsystem = spdk_nvmf_subsystem_get_next(subsystem);

	if (subsystem) {
		spdk_nvmf_subsystem_stop(subsystem, nvmf_tgt_subsystem_stopped, NULL);
		return;
	}

	g_tgt_state = NVMF_TGT_FINI_DESTROY_POLL_GROUPS;
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_destroy_done(void *ctx, int status)
{
	struct nvmf_tgt_host_trid *trid, *tmp_trid;

	g_tgt_state = NVMF_TGT_STOPPED;

	TAILQ_FOREACH_SAFE(trid, &g_nvmf_tgt_host_trids, link, tmp_trid) {
		TAILQ_REMOVE(&g_nvmf_tgt_host_trids, trid, link);
		free(trid);
	}

	free(g_spdk_nvmf_tgt_conf);
	g_spdk_nvmf_tgt_conf = NULL;
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_parse_conf_done(int status)
{
	g_tgt_state = (status == 0) ? NVMF_TGT_INIT_CREATE_POLL_GROUPS : NVMF_TGT_ERROR;
	nvmf_tgt_advance_state();
}

static void
nvmf_tgt_parse_conf_start(void *ctx)
{
	if (spdk_nvmf_parse_conf(nvmf_tgt_parse_conf_done)) {
		SPDK_ERRLOG("spdk_nvmf_parse_conf() failed\n");
		g_tgt_state = NVMF_TGT_ERROR;
		nvmf_tgt_advance_state();
	}
}

static void
nvmf_tgt_advance_state(void)
{
	enum nvmf_tgt_state prev_state;
	int rc = -1;

	do {
		prev_state = g_tgt_state;

		switch (g_tgt_state) {
		case NVMF_TGT_INIT_NONE: {
			g_tgt_state = NVMF_TGT_INIT_PARSE_CONFIG;
			break;
		}
		case NVMF_TGT_INIT_PARSE_CONFIG:
			/* Send message to self to call parse conf func.
			 * Prevents it from possibly performing cb before getting
			 * out of this function, which causes problems. */
			spdk_thread_send_msg(spdk_get_thread(), nvmf_tgt_parse_conf_start, NULL);
			break;
		case NVMF_TGT_INIT_CREATE_POLL_GROUPS:
			/* Send a message to each thread and create a poll group */
			spdk_for_each_thread(nvmf_tgt_create_poll_group,
					     NULL,
					     nvmf_tgt_create_poll_group_done);
			break;
		case NVMF_TGT_INIT_START_SUBSYSTEMS: {
			struct spdk_nvmf_subsystem *subsystem;

			subsystem = spdk_nvmf_subsystem_get_first(g_spdk_nvmf_tgt);

			if (subsystem) {
				spdk_nvmf_subsystem_start(subsystem, nvmf_tgt_subsystem_started, NULL);
			} else {
				g_tgt_state = NVMF_TGT_INIT_START_ACCEPTOR;
			}
			break;
		}
		case NVMF_TGT_INIT_START_ACCEPTOR:
			g_acceptor_poller = spdk_poller_register(acceptor_poll, g_spdk_nvmf_tgt,
					    g_spdk_nvmf_tgt_conf->acceptor_poll_rate);
			SPDK_INFOLOG(SPDK_LOG_NVMF, "Acceptor running\n");
			g_tgt_state = NVMF_TGT_RUNNING;
			break;
		case NVMF_TGT_RUNNING:
			spdk_subsystem_init_next(0);
			break;
		case NVMF_TGT_FINI_STOP_SUBSYSTEMS: {
			struct spdk_nvmf_subsystem *subsystem;

			subsystem = spdk_nvmf_subsystem_get_first(g_spdk_nvmf_tgt);

			if (subsystem) {
				spdk_nvmf_subsystem_stop(subsystem, nvmf_tgt_subsystem_stopped, NULL);
			} else {
				g_tgt_state = NVMF_TGT_FINI_DESTROY_POLL_GROUPS;
			}
			break;
		}
		case NVMF_TGT_FINI_DESTROY_POLL_GROUPS:
			/* Send a message to each thread and destroy the poll group */
			spdk_for_each_thread(nvmf_tgt_destroy_poll_group,
					     NULL,
					     nvmf_tgt_destroy_poll_group_done);
			break;
		case NVMF_TGT_FINI_STOP_ACCEPTOR:
			spdk_poller_unregister(&g_acceptor_poller);
			g_tgt_state = NVMF_TGT_FINI_FREE_RESOURCES;
			break;
		case NVMF_TGT_FINI_FREE_RESOURCES:
			spdk_nvmf_tgt_destroy(g_spdk_nvmf_tgt, nvmf_tgt_destroy_done, NULL);
			break;
		case NVMF_TGT_STOPPED:
			spdk_subsystem_fini_next();
			return;
		case NVMF_TGT_ERROR:
			spdk_subsystem_init_next(rc);
			return;
		}

	} while (g_tgt_state != prev_state);
}

static void
spdk_nvmf_subsystem_init(void)
{
	g_tgt_state = NVMF_TGT_INIT_NONE;
	nvmf_tgt_advance_state();
}

static char *
get_conn_sched_string(enum spdk_nvmf_connect_sched sched)
{
	if (sched == CONNECT_SCHED_HOST_IP) {
		return "hostip";
	} else {
		return "roundrobin";
	}
}

static void
spdk_nvmf_subsystem_write_config_json(struct spdk_json_write_ctx *w)
{
	spdk_json_write_array_begin(w);

	spdk_json_write_object_begin(w);
	spdk_json_write_named_string(w, "method", "set_nvmf_target_config");

	spdk_json_write_named_object_begin(w, "params");
	spdk_json_write_named_uint32(w, "acceptor_poll_rate", g_spdk_nvmf_tgt_conf->acceptor_poll_rate);
	spdk_json_write_named_string(w, "conn_sched",
				     get_conn_sched_string(g_spdk_nvmf_tgt_conf->conn_sched));
	spdk_json_write_object_end(w);
	spdk_json_write_object_end(w);

	spdk_nvmf_tgt_write_config_json(w, g_spdk_nvmf_tgt);
	spdk_json_write_array_end(w);
}

static struct spdk_subsystem g_spdk_subsystem_nvmf = {
	.name = "nvmf",
	.init = spdk_nvmf_subsystem_init,
	.fini = spdk_nvmf_subsystem_fini,
	.write_config_json = spdk_nvmf_subsystem_write_config_json,
};

SPDK_SUBSYSTEM_REGISTER(g_spdk_subsystem_nvmf)
SPDK_SUBSYSTEM_DEPEND(nvmf, bdev)