Spdk/test/app/fuzz/iscsi_fuzz/iscsi_fuzz.c

/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright (C) 2019 Intel Corporation.
 *   All rights reserved.
 */

#include "spdk/stdinc.h"
#include "spdk/event.h"
#include "spdk/util.h"
#include "spdk/string.h"
#include "spdk/likely.h"
#include "spdk/json.h"
#include "spdk/endian.h"
#include "spdk/bdev.h"
#include "spdk/notify.h"
#include "spdk/scsi.h"
#include "spdk_internal/mock.h"
#include "spdk/scsi_spec.h"
#include "iscsi/conn.h"
#include "iscsi/iscsi.c"
#include "scsi/scsi_internal.h"
#include "spdk/sock.h"

#define GET_PDU_LOOP_COUNT	16
#define DEFAULT_RUNTIME		30	/* seconds */
#define MAX_RUNTIME_S		86400	/* 24 hours */

/* Global run state */
uint64_t		g_runtime_ticks;
int			g_runtime;
int			g_num_active_threads;
bool			g_run = true;
bool			g_is_valid_opcode = true;

SPDK_LOG_REGISTER_COMPONENT(iscsi)

/* Global resources */
TAILQ_HEAD(, spdk_iscsi_pdu)		g_get_pdu_list;
TAILQ_HEAD(, fuzz_iscsi_dev_ctx)	g_dev_list = TAILQ_HEAD_INITIALIZER(g_dev_list);
struct spdk_poller			*g_app_completion_poller;
void					*g_valid_buffer;
unsigned int				g_random_seed;
char					*g_tgt_ip = "127.0.0.1";
char					*g_tgt_port = "3260";
/* TBD: Discovery login to get target information. We use fixed IQN for target for now. */
char					*g_tgt_name = "iqn.2016-06.io.spdk:disk1";
char					*g_init_name = "iqn.2016-06.io.spdk:fuzzinit";

struct fuzz_iscsi_iov_ctx {
	struct iovec			iov_req;
	struct iovec			iov_data;
	struct iovec			iov_resp;
};

struct fuzz_iscsi_io_ctx {
	struct fuzz_iscsi_iov_ctx		iov_ctx;
	union {
		struct iscsi_bhs		*bhs;
		struct iscsi_bhs_nop_out	*nop_out_req;
		struct iscsi_bhs_scsi_req	*scsi_req;
		struct iscsi_bhs_task_req	*task_req;
		struct iscsi_bhs_login_req	*login_req;
		struct iscsi_bhs_text_req	*text_req;
		struct iscsi_bhs_data_out	*data_out_req;
		struct iscsi_bhs_logout_req	*logout_req;
		struct iscsi_bhs_snack_req	*snack_req;
	} req;
};

struct fuzz_iscsi_dev_ctx {
	struct spdk_iscsi_sess			sess;
	struct spdk_iscsi_conn			*conn;
	struct fuzz_iscsi_io_ctx		io_ctx;

	struct spdk_thread			*thread;
	struct spdk_poller			*poller;
	unsigned int				random_seed, current_cmd_sn;
	uint64_t				num_sent_pdus;
	uint64_t				num_valid_pdus;

	TAILQ_ENTRY(fuzz_iscsi_dev_ctx)		link;
};

static void
fuzz_fill_random_bytes(char *character_repr, size_t len, unsigned int *rand_seed)
{
	size_t i;

	for (i = 0; i < len; i++) {
		character_repr[i] = rand_r(rand_seed) % UINT8_MAX;
	}
}

static char *
fuzz_get_value_base_64_buffer(void *item, size_t len)
{
	char *value_string;
	size_t total_size;
	int rc;

	/* Null pointer */
	total_size = spdk_base64_get_encoded_strlen(len) + 1;

	value_string = calloc(1, total_size);
	if (value_string == NULL) {
		return NULL;
	}

	rc = spdk_base64_encode(value_string, item, len);
	if (rc < 0) {
		free(value_string);
		return NULL;
	}

	return value_string;
}

int
iscsi_chap_get_authinfo(struct iscsi_chap_auth *auth, const char *authuser,
			int ag_tag)
{
	return 0;
}

void
shutdown_iscsi_conns_done(void)
{
	return;
}

void
iscsi_put_pdu(struct spdk_iscsi_pdu *pdu)
{
	if (!pdu) {
		return;
	}

	pdu->ref--;
	if (pdu->ref < 0) {
		pdu->ref = 0;
	}

	if (pdu->ref == 0) {
		if (pdu->data) {
			free(pdu->data);
		}
		free(pdu);
	}
}

struct spdk_iscsi_pdu *
iscsi_get_pdu(struct spdk_iscsi_conn *conn)
{
	struct spdk_iscsi_pdu *pdu;

	pdu = calloc(1, sizeof(*pdu));
	if (!pdu) {
		return NULL;
	}

	pdu->ref = 1;
	pdu->conn = conn;

	return pdu;
}

static void
iscsi_task_free(struct spdk_scsi_task *scsi_task)
{
	struct spdk_iscsi_task *task = iscsi_task_from_scsi_task(scsi_task);

	assert(task->parent == NULL);

	iscsi_task_disassociate_pdu(task);
	assert(task->conn->pending_task_cnt > 0);
	task->conn->pending_task_cnt--;
	free(task);
}

struct spdk_iscsi_task *
iscsi_task_get(struct spdk_iscsi_conn *conn, struct spdk_iscsi_task *parent,
	       spdk_scsi_task_cpl cpl_fn)
{
	struct spdk_iscsi_task *task;

	/* iSCSI subtask is not necessary for now. */
	assert(parent == NULL);

	task = calloc(1, sizeof(*task));
	if (!task) {
		printf("Unable to get task\n");
		abort();
	}

	task->conn = conn;
	assert(conn->pending_task_cnt < UINT32_MAX);
	conn->pending_task_cnt++;
	spdk_scsi_task_construct(&task->scsi, cpl_fn, iscsi_task_free);

	return task;
}

static void
cleanup(void)
{
	struct fuzz_iscsi_dev_ctx *dev_ctx, *tmp;

	TAILQ_FOREACH_SAFE(dev_ctx, &g_dev_list, link, tmp) {
		printf("device %p stats: Sent %" PRIu64 " valid opcode PDUs, %" PRIu64 " invalid opcode PDUs.\n",
		       dev_ctx, dev_ctx->num_valid_pdus,
		       dev_ctx->num_sent_pdus - dev_ctx->num_valid_pdus);
		free(dev_ctx);
	}

	spdk_free(g_valid_buffer);
}

/* data dumping functions begin */
static int
dump_iscsi_cmd(void *ctx, const void *data, size_t size)
{
	fprintf(stderr, "%s\n", (const char *)data);
	return 0;
}

static void
print_scsi_io_data(struct spdk_json_write_ctx *w, struct fuzz_iscsi_io_ctx *io_ctx)
{
	char *data_segment_len;

	data_segment_len = fuzz_get_value_base_64_buffer((void *)io_ctx->req.bhs->data_segment_len,
			   sizeof(io_ctx->req.bhs->data_segment_len));

	spdk_json_write_named_uint32(w, "opcode", io_ctx->req.bhs->opcode);
	spdk_json_write_named_uint32(w, "immediate", io_ctx->req.bhs->immediate);
	spdk_json_write_named_uint32(w, "reserved", io_ctx->req.bhs->reserved);
	spdk_json_write_named_uint32(w, "total_ahs_len", io_ctx->req.bhs->total_ahs_len);
	spdk_json_write_named_string(w, "data_segment_len", data_segment_len);
	spdk_json_write_named_uint32(w, "itt", io_ctx->req.bhs->itt);
	spdk_json_write_named_uint32(w, "exp_stat_sn", io_ctx->req.bhs->exp_stat_sn);

	free(data_segment_len);
}

static void
print_req_obj(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
{
	struct spdk_json_write_ctx *w;

	w = spdk_json_write_begin(dump_iscsi_cmd, NULL, SPDK_JSON_WRITE_FLAG_FORMATTED);
	spdk_json_write_named_object_begin(w, "bhs");
	print_scsi_io_data(w, io_ctx);
	spdk_json_write_object_end(w);
	spdk_json_write_end(w);
}

/* data dumping functions end */

/* dev initialization begin */
static int
fuzz_iscsi_dev_init(void)
{
	struct fuzz_iscsi_dev_ctx *dev_ctx;
	int rc = 0;

	dev_ctx = calloc(1, sizeof(*dev_ctx));
	if (dev_ctx == NULL) {
		return -ENOMEM;
	}

	dev_ctx->thread = spdk_get_thread();
	if (dev_ctx->thread == NULL) {
		fprintf(stderr, "Unable to get a thread for a fuzz device.\n");
		rc = -EINVAL;
		goto error_out;
	}

	dev_ctx->current_cmd_sn = 0;

	TAILQ_INSERT_TAIL(&g_dev_list, dev_ctx, link);
	return 0;

error_out:
	free(dev_ctx);
	return rc;
}
/* dev initialization end */

/* build requests begin */
static void
prep_iscsi_pdu_bhs_opcode_cmd(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
{
	io_ctx->iov_ctx.iov_req.iov_len = sizeof(struct iscsi_bhs);
	fuzz_fill_random_bytes((char *)io_ctx->req.bhs, sizeof(struct iscsi_bhs),
			       &dev_ctx->random_seed);
}
/* build requests end */

static int
iscsi_pdu_hdr_op_login_rsp(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
{
	return 0;
}

static int
iscsi_fuzz_pdu_hdr_handle(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
{
	int opcode;
	int rc = 0;

	opcode = pdu->bhs.opcode;
	if (opcode == ISCSI_OP_LOGIN_RSP) {
		return iscsi_pdu_hdr_op_login_rsp(conn, pdu);
	}

	switch (opcode) {
	case ISCSI_OP_LOGOUT_RSP:
		fprintf(stderr, "Received logout hdr_handle response opcode(0x26) from Target.\n");
		conn->is_logged_out = true;
		break;
	case ISCSI_OP_NOPIN:
	case ISCSI_OP_SCSI_RSP:
	case ISCSI_OP_TASK_RSP:
	case ISCSI_OP_TEXT_RSP:
	case ISCSI_OP_SCSI_DATAIN:
	case ISCSI_OP_R2T:
	case ISCSI_OP_ASYNC:
	case ISCSI_OP_VENDOR_3C:
	case ISCSI_OP_VENDOR_3D:
	case ISCSI_OP_VENDOR_3E:
		fprintf(stderr, "Received hdr_handle response opcode from Target is 0x%x.\n", pdu->bhs.opcode);
		break;
	case ISCSI_OP_REJECT:
		fprintf(stderr, "Received rejected hdr_handle response opcode(0x3f) from Target.\n");
		break;
	default:
		rc = -1;
		break;
	}

	return rc;
}

static int
iscsi_pdu_payload_op_login_rsp(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
{
	struct iscsi_bhs_login_rsp *rsph;

	rsph = (struct iscsi_bhs_login_rsp *)&pdu->bhs;
	if (rsph == NULL) {
		return -1;
	}

	assert(rsph->tsih != 0);
	assert(rsph->status_class == 0);
	assert(ISCSI_BHS_LOGIN_GET_TBIT(rsph->flags));
	assert(!(rsph->flags & ISCSI_LOGIN_CONTINUE));
	assert((rsph->flags & ISCSI_LOGIN_NEXT_STAGE_MASK) == ISCSI_LOGIN_NEXT_STAGE_3);

	/* We got the Login Final Response and move to Full-Feature Phase. */
	conn->full_feature = 1;
	return 0;
}

static int
iscsi_fuzz_pdu_payload_handle(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
{
	int opcode;
	int rc = 0;

	opcode = pdu->bhs.opcode;
	fprintf(stderr, "Received payload_handle response opcode from Target is 0x%x.\n", opcode);

	switch (opcode) {
	case ISCSI_OP_LOGIN_RSP:
		rc = iscsi_pdu_payload_op_login_rsp(conn, pdu);
		break;
	case ISCSI_OP_NOPIN:
	case ISCSI_OP_SCSI_RSP:
	case ISCSI_OP_TASK_RSP:
	case ISCSI_OP_TEXT_RSP:
	case ISCSI_OP_SCSI_DATAIN:
	case ISCSI_OP_R2T:
	case ISCSI_OP_ASYNC:
	case ISCSI_OP_VENDOR_3C:
	case ISCSI_OP_VENDOR_3D:
	case ISCSI_OP_VENDOR_3E:
	case ISCSI_OP_REJECT:
		break;
	default:
		rc = -1;
		break;
	}

	return rc;
}

static int
iscsi_fuzz_read_pdu(struct spdk_iscsi_conn *conn)
{
	enum iscsi_pdu_recv_state prev_state;
	struct spdk_iscsi_pdu *pdu;
	uint32_t data_len;
	int rc;

	do {
		prev_state = conn->pdu_recv_state;
		pdu = conn->pdu_in_progress;

		switch (conn->pdu_recv_state) {
		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY:
			assert(conn->pdu_in_progress == NULL);

			conn->pdu_in_progress = iscsi_get_pdu(conn);
			if (conn->pdu_in_progress == NULL) {
				return SPDK_ISCSI_CONNECTION_FATAL;
			}
			TAILQ_INSERT_TAIL(&g_get_pdu_list, conn->pdu_in_progress, tailq);
			conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_HDR;
			break;
		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_HDR:
			if (pdu->bhs_valid_bytes < ISCSI_BHS_LEN) {
				rc = iscsi_conn_read_data(conn,
							  ISCSI_BHS_LEN - pdu->bhs_valid_bytes,
							  (uint8_t *)&pdu->bhs + pdu->bhs_valid_bytes);
				if (rc < 0) {
					conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
					break;
				}
				pdu->bhs_valid_bytes += rc;
				if (pdu->bhs_valid_bytes < ISCSI_BHS_LEN) {
					return 0;
				}
			}

			pdu->data_segment_len = ISCSI_ALIGN(DGET24(pdu->bhs.data_segment_len));

			rc = iscsi_fuzz_pdu_hdr_handle(conn, pdu);
			if (rc < 0) {
				printf("Critical error is detected. Close the connection\n");
				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
				break;
			}

			if (conn->is_logged_out) {
				printf("pdu received after logout\n");
				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
				break;
			}

			conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD;
			break;
		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD:
			data_len = pdu->data_segment_len;
			if (data_len != 0 && pdu->data == NULL) {
				pdu->data = calloc(1, data_len);
				if (pdu->data == NULL) {
					return 0;
				}
			}

			/* copy the actual data into local buffer */
			if (pdu->data_valid_bytes < data_len) {
				rc = iscsi_conn_read_data_segment(conn, pdu,
								  pdu->data_valid_bytes,
								  data_len - pdu->data_valid_bytes);
				if (rc < 0) {
					conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
					break;
				}
				pdu->data_valid_bytes += rc;
				if (pdu->data_valid_bytes < data_len) {
					return 0;
				}
			}

			/* All data for this PDU has now been read from the socket. */
			spdk_trace_record(TRACE_ISCSI_READ_PDU, conn->id, pdu->data_valid_bytes,
					  (uintptr_t)pdu, pdu->bhs.opcode);

			if (!pdu->is_rejected) {
				rc = iscsi_fuzz_pdu_payload_handle(conn, pdu);
			} else {
				rc = 0;
			}
			if (rc == 0) {
				spdk_trace_record(TRACE_ISCSI_TASK_EXECUTED, 0, 0, (uintptr_t)pdu);
				conn->pdu_in_progress = NULL;
				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY;
				return 1;
			} else {
				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
			}
			break;
		case ISCSI_PDU_RECV_STATE_ERROR:
			return SPDK_ISCSI_CONNECTION_FATAL;
		default:
			assert(false);
			printf("code should not come here\n");
			break;
		}
	} while (prev_state != conn->pdu_recv_state);

	return 0;
}

#define GET_PDU_LOOP_COUNT	16

static int
fuzz_iscsi_handle_incoming_pdus(struct spdk_iscsi_conn *conn)
{
	int i, rc;

	/* Read new PDUs from network */
	for (i = 0; i < GET_PDU_LOOP_COUNT; i++) {
		rc = iscsi_fuzz_read_pdu(conn);
		if (rc == 0) {
			break;
		} else if (rc < 0) {
			return rc;
		}
	}

	return i;
}

static void
fuzz_iscsi_send_login_request(struct fuzz_iscsi_dev_ctx *dev_ctx, uint8_t session_type)
{
	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
	struct spdk_iscsi_pdu *req_pdu;
	struct iscsi_bhs_login_req *login_req;
	struct spdk_iscsi_conn *conn = dev_ctx->conn;

	req_pdu = iscsi_get_pdu(conn);
	req_pdu->writev_offset = 0;
	req_pdu->hdigest_valid_bytes = 0;
	req_pdu->ahs_valid_bytes = 0;
	req_pdu->data_buf_len = 8192;
	req_pdu->data = calloc(1, 8192);
	assert(req_pdu->data != NULL);
	req_pdu->data_segment_len = 0;

	login_req = (struct iscsi_bhs_login_req *)&req_pdu->bhs;
	io_ctx = &dev_ctx->io_ctx;
	io_ctx->req.login_req = login_req;
	io_ctx->req.login_req->version_min = 0;
	/* a new session */
	io_ctx->req.login_req->tsih = 0;

	req_pdu->bhs.opcode = ISCSI_OP_LOGIN;
	req_pdu->bhs.immediate = 1;
	req_pdu->bhs.reserved = 0;
	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
	req_pdu->bhs.total_ahs_len = 0;

	/* An initiator that chooses to operate without iSCSI security and with
	 * all the operational parameters taking the default values issues the
	 * Login with the T bit set to 1, the CSG set to
	 * LoginOperationalNegotiation, and the NSG set to FullFeaturePhase.
	 *
	 * Byte /	   0	   |	   1	   |	   2	   |	   3	   |
	 *	   |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
	 *	   +---------------+---------------+---------------+---------------+
	 *	  0|.|1| 0x03	   |T|C|.|.|CSG|NSG| Version-max   | Version-min   |
	 */
	req_pdu->bhs.flags = ISCSI_LOGIN_TRANSIT | (ISCSI_OPERATIONAL_NEGOTIATION_PHASE << 2) |
			     ISCSI_FULL_FEATURE_PHASE;

	req_pdu->data_segment_len = iscsi_append_text("InitiatorName", g_init_name,
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("HeaderDigest", "None",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("DataDigest", "None",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("DefaultTime2Wait", "2",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("DefaultTime2Retain", "0",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("IFMarker", "No",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("OFMarker", "No",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	req_pdu->data_segment_len = iscsi_append_text("ErrorRecoveryLevel", "0",
				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);

	if (session_type == SESSION_TYPE_DISCOVERY) {
		/* Discovery PDU */
		conn->sess->session_type = SESSION_TYPE_DISCOVERY;
		req_pdu->data_segment_len = iscsi_append_text("SessionType", "Discovery",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("MaxRecvDataSegmentLength", "32768",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	} else {
		/* Login PDU */
		conn->sess->session_type = SESSION_TYPE_NORMAL;
		req_pdu->data_segment_len = iscsi_append_text("SessionType", "Normal",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("TargetName", g_tgt_name,
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("InitialR2T", "No",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("ImmediateData", "Yes",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("MaxBurstLength", "16776192",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("FirstBurstLength", "262144",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("MaxOutstandingR2T", "1",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("MaxConnections", "1",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("DataPDUInOrder", "Yes",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("DataSequenceInOrder", "Yes",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
		req_pdu->data_segment_len = iscsi_append_text("MaxRecvDataSegmentLength", "262144",
					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
	}

	DSET24(req_pdu->bhs.data_segment_len, req_pdu->data_segment_len);
	iscsi_conn_write_pdu(conn, req_pdu, iscsi_conn_pdu_generic_complete, NULL);
}

static void
fuzz_iscsi_send_logout_request(struct fuzz_iscsi_dev_ctx *dev_ctx)
{
	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
	struct spdk_iscsi_pdu *req_pdu;
	struct iscsi_bhs_logout_req *logout_req;
	struct spdk_iscsi_conn *conn = dev_ctx->conn;

	conn->is_logged_out = true;

	req_pdu = iscsi_get_pdu(conn);
	req_pdu->writev_offset = 0;
	req_pdu->hdigest_valid_bytes = 0;
	req_pdu->ahs_valid_bytes = 0;
	req_pdu->data_buf_len = 0;

	logout_req = (struct iscsi_bhs_logout_req *)&req_pdu->bhs;
	io_ctx = &dev_ctx->io_ctx;
	io_ctx->req.logout_req = logout_req;

	req_pdu->bhs.opcode = ISCSI_OP_LOGOUT;
	req_pdu->bhs.immediate = 1;
	req_pdu->bhs.reserved = 0;
	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
	req_pdu->bhs.total_ahs_len = 0;
	req_pdu->bhs.flags = 0;

	DSET24(req_pdu->bhs.data_segment_len, 0);
	iscsi_conn_write_pdu(conn, req_pdu, iscsi_conn_pdu_generic_complete, conn);
}

static void
iscsi_fuzz_conn_reset(struct spdk_iscsi_conn *conn, struct spdk_iscsi_sess *sess)
{
	conn->sess = sess;
	conn->data_in_cnt = 0;
	conn->params = NULL;
	conn->header_digest = true;
	conn->data_digest = false;
	conn->header_digest = 0;
	conn->MaxRecvDataSegmentLength = 8192;
	conn->full_feature = 0;
	conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY;
	conn->pdu_in_progress = NULL;
	conn->is_logged_out = 0;
}

static void
iscsi_fuzz_sock_connect(struct spdk_iscsi_conn *conn)
{
	const char *host = g_tgt_ip;
	const char *port = g_tgt_port;
	char saddr[INET6_ADDRSTRLEN], caddr[INET6_ADDRSTRLEN];
	uint16_t cport, sport;
	int rc = 0;

	conn->sock = spdk_sock_connect(host, spdk_strtol(port, 10), NULL);
	if (conn->sock == NULL) {
		fprintf(stderr, "connect error(%d): %s\n", errno, spdk_strerror(errno));
		spdk_sock_close(&conn->sock);
		return;
	}
	fprintf(stderr, "\nConnecting to the server on %s:%s\n", host, port);

	rc = spdk_sock_getaddr(conn->sock, saddr, sizeof(saddr), &sport, caddr, sizeof(caddr), &cport);
	if (rc < 0) {
		fprintf(stderr, "Cannot get connection addresses\n");
		spdk_sock_close(&conn->sock);
		return;
	}

	fprintf(stderr, "Connection accepted from (%s, %hu) to (%s, %hu)\n", caddr, cport, saddr, sport);

}

static void
check_successful_op(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
{
	if (g_is_valid_opcode) {
		fprintf(stderr, "Sent a valid opcode PDU.\n");
		dev_ctx->num_valid_pdus++;
	} else {
		fprintf(stderr, "Sent an invalid opcode PDU.\n");
	}
}

/* submit requests begin */
static void
dev_submit_requests(struct fuzz_iscsi_dev_ctx *dev_ctx)
{
	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
	uint8_t opcode;
	struct spdk_iscsi_pdu *req_pdu;
	struct iscsi_bhs *bhs;
	struct iscsi_bhs_nop_out *nop_out_req;
	struct iscsi_bhs_scsi_req *scsi_req;
	struct iscsi_bhs_task_req *task_req;
	struct iscsi_bhs_text_req *text_req;
	struct iscsi_bhs_data_out *data_out_req;
	struct iscsi_bhs_snack_req *snack_req;
	unsigned int rand_seed;
	bool is_p99;

	g_is_valid_opcode = true;

	/* Random PDU */
	opcode = rand() % 0x3f;
	fprintf(stderr,	"Random request bhs.opcode of Initiator is 0x%x.\n", opcode);

	if ((opcode == ISCSI_OP_LOGIN) || (opcode == ISCSI_OP_LOGOUT)) {
		/* only need send next */
		fprintf(stderr, "LOGIN and LOGOUT opcodes are ignored here.\n");
		return;
	}

	req_pdu = iscsi_get_pdu(dev_ctx->conn);
	req_pdu->writev_offset = 0;
	req_pdu->hdigest_valid_bytes = 0;
	req_pdu->ahs_valid_bytes = 0;
	req_pdu->data_buf_len = 0;

	dev_ctx->conn->sess->session_type = SESSION_TYPE_NORMAL;

	io_ctx = &dev_ctx->io_ctx;

	switch (opcode) {
	case ISCSI_OP_NOPOUT:
		nop_out_req = (struct iscsi_bhs_nop_out *)&req_pdu->bhs;
		io_ctx->req.nop_out_req = nop_out_req;
		break;
	case ISCSI_OP_SCSI:
		scsi_req = (struct iscsi_bhs_scsi_req *)&req_pdu->bhs;
		io_ctx->req.scsi_req = scsi_req;
		break;
	case ISCSI_OP_TASK:
		task_req = (struct iscsi_bhs_task_req *)&req_pdu->bhs;
		io_ctx->req.task_req = task_req;
		break;
	case ISCSI_OP_TEXT:
		text_req = (struct iscsi_bhs_text_req *)&req_pdu->bhs;
		io_ctx->req.text_req = text_req;
		break;
	case ISCSI_OP_SCSI_DATAOUT:
		data_out_req = (struct iscsi_bhs_data_out *)&req_pdu->bhs;
		io_ctx->req.data_out_req = data_out_req;
		break;
	case ISCSI_OP_SNACK:
		snack_req = (struct iscsi_bhs_snack_req *)&req_pdu->bhs;
		io_ctx->req.snack_req = snack_req;
		break;
	default:
		bhs = (struct iscsi_bhs *)&req_pdu->bhs;
		io_ctx->req.bhs = bhs;
		g_is_valid_opcode = false;
		break;
	}

	prep_iscsi_pdu_bhs_opcode_cmd(dev_ctx, io_ctx);
	io_ctx->req.bhs->opcode = opcode;
	req_pdu->bhs.opcode = opcode;
	req_pdu->bhs.immediate = 1;
	req_pdu->bhs.reserved = 0;
	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
	req_pdu->bhs.total_ahs_len = 0;
	req_pdu->bhs.stat_sn = 0;
	DSET24(req_pdu->bhs.data_segment_len, 0);

	if (opcode <= ISCSI_OP_TEXT) {
		rand_seed = time(NULL);
		is_p99 = rand_r(&rand_seed) % 100 == 0 ? true : false;
		if (!is_p99) { /* Remaining 1% */
			switch (opcode) {
			case ISCSI_OP_NOPOUT:
				if (req_pdu->bhs.immediate) {
					io_ctx->req.nop_out_req->cmd_sn = dev_ctx->current_cmd_sn;
				} else {
					io_ctx->req.nop_out_req->cmd_sn = dev_ctx->current_cmd_sn++;
				}
				break;
			case ISCSI_OP_SCSI:
				if (req_pdu->bhs.immediate) {
					io_ctx->req.scsi_req->cmd_sn = dev_ctx->current_cmd_sn;
				} else {
					io_ctx->req.scsi_req->cmd_sn = dev_ctx->current_cmd_sn++;
				}
				break;
			case ISCSI_OP_TASK:
				if (req_pdu->bhs.immediate) {
					io_ctx->req.task_req->cmd_sn = dev_ctx->current_cmd_sn;
				} else {
					io_ctx->req.task_req->cmd_sn = dev_ctx->current_cmd_sn++;
				}
				break;
			case ISCSI_OP_TEXT:
				if (req_pdu->bhs.immediate) {
					io_ctx->req.text_req->cmd_sn = dev_ctx->current_cmd_sn;
				} else {
					io_ctx->req.text_req->cmd_sn = dev_ctx->current_cmd_sn++;
				}
				break;
			default:
				break;
			}
		}
	}

	if (opcode == ISCSI_OP_SCSI) {
		/* avoid ((R_bit != 0) && (W_bit != 0)) is true */
		io_ctx->req.scsi_req->read_bit = 0;
		io_ctx->req.scsi_req->write_bit = 0;
	}

	if (opcode == ISCSI_OP_TEXT) {
		/* avoid: (F_bit && C_bit) is true */
		io_ctx->req.text_req->flags = 0;
		/* avoid: correct itt is not equal to the current itt */
		io_ctx->req.text_req->itt = 0;
	}

	fprintf(stderr, "Dumping this request bhs contents now.\n");
	print_req_obj(dev_ctx, io_ctx);

	check_successful_op(dev_ctx, io_ctx);
	dev_ctx->num_sent_pdus++;

	iscsi_conn_write_pdu(dev_ctx->conn, req_pdu,
			     iscsi_conn_pdu_generic_complete, NULL);
}
/* submit requests end */

static int
poll_dev(void *ctx)
{
	struct fuzz_iscsi_dev_ctx *dev_ctx = ctx;
	struct spdk_iscsi_conn *conn = dev_ctx->conn;
	uint64_t current_ticks;
	struct spdk_iscsi_pdu *pdu, *tmp;

	current_ticks = spdk_get_ticks();
	if (current_ticks > g_runtime_ticks) {
		g_run = false;
	}

	if (!g_run) {
		/* Logout PDU */
		fuzz_iscsi_send_logout_request(dev_ctx);
		fuzz_iscsi_handle_incoming_pdus(conn);

		TAILQ_FOREACH_SAFE(pdu, &g_get_pdu_list, tailq, tmp) {
			TAILQ_REMOVE(&g_get_pdu_list, pdu, tailq);
			iscsi_put_pdu(pdu);
		}

		spdk_sock_close(&conn->sock);

		TAILQ_FOREACH_SAFE(pdu, &conn->write_pdu_list, tailq, tmp) {
			TAILQ_REMOVE(&conn->write_pdu_list, pdu, tailq);
			iscsi_put_pdu(pdu);
		}

		free(conn);

		spdk_poller_unregister(&dev_ctx->poller);
		__sync_sub_and_fetch(&g_num_active_threads, 1);

		return -1;
	}

	if (conn->is_logged_out) {
		spdk_sock_close(&conn->sock);
		iscsi_fuzz_conn_reset(conn, &dev_ctx->sess);
		iscsi_fuzz_sock_connect(conn);
		usleep(1000);

		/* Login PDU */
		fuzz_iscsi_send_login_request(dev_ctx, SESSION_TYPE_NORMAL);
	} else if (conn->full_feature == 1) {
		dev_submit_requests(dev_ctx);
	}

	spdk_sock_flush(conn->sock);

	fuzz_iscsi_handle_incoming_pdus(conn);

	return 0;
}

static void
start_io(void *ctx)
{
	struct fuzz_iscsi_dev_ctx *dev_ctx = ctx;

	dev_ctx->sess.ExpCmdSN = 0;
	dev_ctx->sess.MaxCmdSN = 64;
	dev_ctx->sess.MaxBurstLength = SPDK_ISCSI_MAX_RECV_DATA_SEGMENT_LENGTH;
	dev_ctx->sess.MaxOutstandingR2T = 1;
	dev_ctx->sess.tag = 1;
	dev_ctx->sess.tsih = 256;

	dev_ctx->conn = calloc(1, sizeof(*dev_ctx->conn));
	assert(dev_ctx->conn != NULL);
	TAILQ_INIT(&dev_ctx->conn->write_pdu_list);

	iscsi_fuzz_conn_reset(dev_ctx->conn, &dev_ctx->sess);
	iscsi_fuzz_sock_connect(dev_ctx->conn);
	usleep(1000);

	/* Login PDU */
	fuzz_iscsi_send_login_request(dev_ctx, SESSION_TYPE_NORMAL);

	if (g_random_seed) {
		dev_ctx->random_seed = g_random_seed;
	} else {
		dev_ctx->random_seed = spdk_get_ticks();
	}

	dev_ctx->poller = SPDK_POLLER_REGISTER(poll_dev, dev_ctx, 0);
	if (dev_ctx->poller == NULL) {
		return;
	}
}

static int
check_app_completion(void *ctx)
{
	if (g_num_active_threads == 0) {
		spdk_poller_unregister(&g_app_completion_poller);
		printf("Fuzzing completed. Shutting down the fuzz application.\n\n");
		cleanup();
		spdk_app_stop(0);
	}
	return 0;
}

static void
begin_iscsi_fuzz(void *ctx)
{
	struct fuzz_iscsi_dev_ctx *dev_ctx;
	int rc;

	g_runtime_ticks = spdk_get_ticks() + g_runtime * spdk_get_ticks_hz();

	g_valid_buffer = spdk_malloc(0x1000, 0x200, NULL, SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_SHARE);
	if (g_valid_buffer == NULL) {
		fprintf(stderr, "Failed to allocate a valid buffer for random PDUs\n");
		goto out;
	}

	rc = fuzz_iscsi_dev_init();
	if (rc) {
		fprintf(stderr, "fuzz_iscsi_dev_init() failed.\n");
		goto out;
	}

	TAILQ_FOREACH(dev_ctx, &g_dev_list, link) {
		assert(dev_ctx->thread != NULL);
		spdk_thread_send_msg(dev_ctx->thread, start_io, dev_ctx);
		__sync_add_and_fetch(&g_num_active_threads, 1);
	}

	g_app_completion_poller = SPDK_POLLER_REGISTER(check_app_completion, NULL, 1000000);
	if (g_app_completion_poller == NULL) {
		fprintf(stderr, "Failed to register a poller for test completion checking.\n");
		goto out;
	}

	return;
out:
	cleanup();
	spdk_app_stop(0);
}

static void
iscsi_fuzz_usage(void)
{
	fprintf(stderr, " -T <path>                 iSCSI Target IP address.\n");
	fprintf(stderr, " -S <integer>              Seed value for test.\n");
	fprintf(stderr,
		" -t <integer>              Time in seconds to run the fuzz test. Only valid if -j is not specified.\n");
}

static int
iscsi_fuzz_parse(int ch, char *arg)
{
	int64_t error_test;

	switch (ch) {
	case 'T':
		g_tgt_ip = optarg;
		break;
	case 'S':
		error_test = spdk_strtol(arg, 10);
		if (error_test < 0) {
			fprintf(stderr, "Invalid value supplied for the random seed.\n");
			return -1;
		} else {
			g_random_seed = error_test;
		}
		break;
	case 't':
		g_runtime = spdk_strtol(optarg, 10);
		if (g_runtime <= 0 || g_runtime > MAX_RUNTIME_S) {
			fprintf(stderr, "You must supply a positive runtime value less than %d.\n", MAX_RUNTIME_S);
			return -1;
		}
		break;
	case '?':
	default:
		iscsi_fuzz_usage();
		return -EINVAL;
	}

	return 0;
}

int
main(int argc, char **argv)
{
	struct spdk_app_opts opts = {};
	int rc;

	g_runtime = DEFAULT_RUNTIME;
	srand((unsigned)time(0));

	TAILQ_INIT(&g_get_pdu_list);

	spdk_app_opts_init(&opts, sizeof(opts));
	opts.name = "iscsi_fuzz";

	if ((rc = spdk_app_parse_args(argc, argv, &opts, "T:S:t:", NULL, iscsi_fuzz_parse,
				      iscsi_fuzz_usage) != SPDK_APP_PARSE_ARGS_SUCCESS)) {
		return rc;
	}

	rc = spdk_app_start(&opts, begin_iscsi_fuzz, NULL);

	spdk_app_fini();
	return rc;
}