text: /*-
   *   BSD LICENSE
   *
   *   Copyright (c) Intel Corporation. All rights reserved.
   *   Copyright (c) 2019, 2020 Mellanox Technologies LTD. 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 "spdk/accel_engine.h"
  #include "spdk/stdinc.h"
  #include "spdk/crc32.h"
  #include "spdk/endian.h"
  #include "spdk/assert.h"
  #include "spdk/thread.h"
  #include "spdk/nvmf_transport.h"
  #include "spdk/string.h"
  #include "spdk/trace.h"
  #include "spdk/util.h"
  #include "spdk/log.h"
  
  #include "spdk_internal/assert.h"
  #include "spdk_internal/nvme_tcp.h"
  #include "spdk_internal/sock.h"
  
  #include "nvmf_internal.h"
  
  #define NVMF_TCP_MAX_ACCEPT_SOCK_ONE_TIME 16
  #define SPDK_NVMF_TCP_DEFAULT_MAX_SOCK_PRIORITY 16
  #define SPDK_NVMF_TCP_DEFAULT_SOCK_PRIORITY 0
  #define SPDK_NVMF_TCP_DEFAULT_CONTROL_MSG_NUM 32
  #define SPDK_NVMF_TCP_DEFAULT_SUCCESS_OPTIMIZATION true
  
  const struct spdk_nvmf_transport_ops spdk_nvmf_transport_tcp;
  
  /* spdk nvmf related structure */
  enum spdk_nvmf_tcp_req_state {
  
  	/* The request is not currently in use */
  	TCP_REQUEST_STATE_FREE = 0,
  
  	/* Initial state when request first received */
  	TCP_REQUEST_STATE_NEW,
  
  	/* The request is queued until a data buffer is available. */
  	TCP_REQUEST_STATE_NEED_BUFFER,
  
  	/* The request is currently transferring data from the host to the controller. */
  	TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
  
  	/* The request is waiting for the R2T send acknowledgement. */
  	TCP_REQUEST_STATE_AWAITING_R2T_ACK,
  
  	/* The request is ready to execute at the block device */
  	TCP_REQUEST_STATE_READY_TO_EXECUTE,
  
  	/* The request is currently executing at the block device */
  	TCP_REQUEST_STATE_EXECUTING,
  
  	/* The request finished executing at the block device */
  	TCP_REQUEST_STATE_EXECUTED,
  
  	/* The request is ready to send a completion */
  	TCP_REQUEST_STATE_READY_TO_COMPLETE,
  
  	/* The request is currently transferring final pdus from the controller to the host. */
  	TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
  
  	/* The request completed and can be marked free. */
  	TCP_REQUEST_STATE_COMPLETED,
  
  	/* Terminator */
  	TCP_REQUEST_NUM_STATES,
  };
  
  static const char *spdk_nvmf_tcp_term_req_fes_str[] = {
  	"Invalid PDU Header Field",
  	"PDU Sequence Error",
  	"Header Digiest Error",
  	"Data Transfer Out of Range",
  	"R2T Limit Exceeded",
  	"Unsupported parameter",
  };
  
  #define OBJECT_NVMF_TCP_IO				0x80
  
  #define TRACE_GROUP_NVMF_TCP				0x5
  #define TRACE_TCP_REQUEST_STATE_NEW					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x0)
  #define TRACE_TCP_REQUEST_STATE_NEED_BUFFER				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x1)
  #define TRACE_TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER		SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x2)
  #define TRACE_TCP_REQUEST_STATE_READY_TO_EXECUTE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x3)
  #define TRACE_TCP_REQUEST_STATE_EXECUTING				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x4)
  #define TRACE_TCP_REQUEST_STATE_EXECUTED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x5)
  #define TRACE_TCP_REQUEST_STATE_READY_TO_COMPLETE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x6)
  #define TRACE_TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST		SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x7)
  #define TRACE_TCP_REQUEST_STATE_COMPLETED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x8)
  #define TRACE_TCP_FLUSH_WRITEBUF_START					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0x9)
  #define TRACE_TCP_FLUSH_WRITEBUF_DONE					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0xA)
  #define TRACE_TCP_READ_FROM_SOCKET_DONE					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0xB)
  #define TRACE_TCP_REQUEST_STATE_AWAIT_R2T_ACK				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_TCP, 0xC)
  
  SPDK_TRACE_REGISTER_FN(nvmf_tcp_trace, "nvmf_tcp", TRACE_GROUP_NVMF_TCP)
  {
  	spdk_trace_register_object(OBJECT_NVMF_TCP_IO, 'r');
  	spdk_trace_register_description("TCP_REQ_NEW",
  					TRACE_TCP_REQUEST_STATE_NEW,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 1, 1, "");
  	spdk_trace_register_description("TCP_REQ_NEED_BUFFER",
  					TRACE_TCP_REQUEST_STATE_NEED_BUFFER,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_TX_H_TO_C",
  					TRACE_TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_RDY_TO_EXECUTE",
  					TRACE_TCP_REQUEST_STATE_READY_TO_EXECUTE,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_EXECUTING",
  					TRACE_TCP_REQUEST_STATE_EXECUTING,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_EXECUTED",
  					TRACE_TCP_REQUEST_STATE_EXECUTED,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_RDY_TO_COMPLETE",
  					TRACE_TCP_REQUEST_STATE_READY_TO_COMPLETE,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_TRANSFER_C2H",
  					TRACE_TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_REQ_COMPLETED",
  					TRACE_TCP_REQUEST_STATE_COMPLETED,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  	spdk_trace_register_description("TCP_WRITE_START",
  					TRACE_TCP_FLUSH_WRITEBUF_START,
  					OWNER_NONE, OBJECT_NONE, 0, 0, "");
  	spdk_trace_register_description("TCP_WRITE_DONE",
  					TRACE_TCP_FLUSH_WRITEBUF_DONE,
  					OWNER_NONE, OBJECT_NONE, 0, 0, "");
  	spdk_trace_register_description("TCP_READ_DONE",
  					TRACE_TCP_READ_FROM_SOCKET_DONE,
  					OWNER_NONE, OBJECT_NONE, 0, 0, "");
  	spdk_trace_register_description("TCP_REQ_AWAIT_R2T_ACK",
  					TRACE_TCP_REQUEST_STATE_AWAIT_R2T_ACK,
  					OWNER_NONE, OBJECT_NVMF_TCP_IO, 0, 1, "");
  }
  
  struct spdk_nvmf_tcp_req  {
  	struct spdk_nvmf_request		req;
  	struct spdk_nvme_cpl			rsp;
  	struct spdk_nvme_cmd			cmd;
  
  	/* A PDU that can be used for sending responses. This is
  	 * not the incoming PDU! */
  	struct nvme_tcp_pdu			*pdu;
  
  	/* In-capsule data buffer */
  	uint8_t					*buf;
  	/*
  	 * The PDU for a request may be used multiple times in serial over
  	 * the request's lifetime. For example, first to send an R2T, then
  	 * to send a completion. To catch mistakes where the PDU is used
  	 * twice at the same time, add a debug flag here for init/fini.
  	 */
  	bool					pdu_in_use;
  	bool					has_incapsule_data;
  
  	/* transfer_tag */
  	uint16_t				ttag;
  
  	enum spdk_nvmf_tcp_req_state		state;
  
  	/*
  	 * h2c_offset is used when we receive the h2c_data PDU.
  	 */
  	uint32_t				h2c_offset;
  
  	STAILQ_ENTRY(spdk_nvmf_tcp_req)		link;
  	TAILQ_ENTRY(spdk_nvmf_tcp_req)		state_link;
  };
  
  struct spdk_nvmf_tcp_qpair {
  	struct spdk_nvmf_qpair			qpair;
  	struct spdk_nvmf_tcp_poll_group		*group;
  	struct spdk_sock			*sock;
  
  	enum nvme_tcp_pdu_recv_state		recv_state;
  	enum nvme_tcp_qpair_state		state;
  
  	/* PDU being actively received */
  	struct nvme_tcp_pdu			pdu_in_progress;
  
  	/* Queues to track the requests in all states */
  	TAILQ_HEAD(, spdk_nvmf_tcp_req)		tcp_req_working_queue;
  	TAILQ_HEAD(, spdk_nvmf_tcp_req)		tcp_req_free_queue;
  
  	/* Number of requests in each state */
  	uint32_t				state_cntr[TCP_REQUEST_NUM_STATES];
  
  	uint8_t					cpda;
  
  	bool					host_hdgst_enable;
  	bool					host_ddgst_enable;
  
  	/* This is a spare PDU used for sending special management
  	 * operations. Primarily, this is used for the initial
  	 * connection response and c2h termination request. */
  	struct nvme_tcp_pdu			*mgmt_pdu;
  
  	/* Arrays of in-capsule buffers, requests, and pdus.
  	 * Each array is 'resource_count' number of elements */
  	void					*bufs;
  	struct spdk_nvmf_tcp_req		*reqs;
  	struct nvme_tcp_pdu			*pdus;
  	uint32_t				resource_count;
  	uint32_t				recv_buf_size;
  
  	struct spdk_nvmf_tcp_port		*port;
  
  	/* IP address */
  	char					initiator_addr[SPDK_NVMF_TRADDR_MAX_LEN];
  	char					target_addr[SPDK_NVMF_TRADDR_MAX_LEN];
  
  	/* IP port */
  	uint16_t				initiator_port;
  	uint16_t				target_port;
  
  	/* Timer used to destroy qpair after detecting transport error issue if initiator does
  	 *  not close the connection.
  	 */
  	struct spdk_poller			*timeout_poller;
  
  
  	TAILQ_ENTRY(spdk_nvmf_tcp_qpair)	link;
  };
  
  struct spdk_nvmf_tcp_control_msg {
  	STAILQ_ENTRY(spdk_nvmf_tcp_control_msg) link;
  };
  
  struct spdk_nvmf_tcp_control_msg_list {
  	void *msg_buf;
  	STAILQ_HEAD(, spdk_nvmf_tcp_control_msg) free_msgs;
  };
  
  struct spdk_nvmf_tcp_poll_group {
  	struct spdk_nvmf_transport_poll_group	group;
  	struct spdk_sock_group			*sock_group;
  
  	TAILQ_HEAD(, spdk_nvmf_tcp_qpair)	qpairs;
  	TAILQ_HEAD(, spdk_nvmf_tcp_qpair)	await_req;
  
  	struct spdk_io_channel			*accel_channel;
  	struct spdk_nvmf_tcp_control_msg_list	*control_msg_list;
  };
  
  struct spdk_nvmf_tcp_port {
  	const struct spdk_nvme_transport_id	*trid;
  	struct spdk_sock			*listen_sock;
  	TAILQ_ENTRY(spdk_nvmf_tcp_port)		link;
  };
  
  struct tcp_transport_opts {
  	bool		c2h_success;
  	uint16_t	control_msg_num;
  	uint32_t	sock_priority;
  };
  
  struct spdk_nvmf_tcp_transport {
  	struct spdk_nvmf_transport		transport;
  	struct tcp_transport_opts               tcp_opts;
  
  	pthread_mutex_t				lock;
  
  	TAILQ_HEAD(, spdk_nvmf_tcp_port)	ports;
  };
  
  static const struct spdk_json_object_decoder tcp_transport_opts_decoder[] = {
  	{
  		"c2h_success", offsetof(struct tcp_transport_opts, c2h_success),
  		spdk_json_decode_bool, true
  	},
  	{
  		"control_msg_num", offsetof(struct tcp_transport_opts, control_msg_num),
  		spdk_json_decode_uint16, true
  	},
  	{
  		"sock_priority", offsetof(struct tcp_transport_opts, sock_priority),
  		spdk_json_decode_uint32, true
  	},
  };
  
  static bool nvmf_tcp_req_process(struct spdk_nvmf_tcp_transport *ttransport,
  				 struct spdk_nvmf_tcp_req *tcp_req);
  static void nvmf_tcp_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group);
  
  static void _nvmf_tcp_send_c2h_data(struct spdk_nvmf_tcp_qpair *tqpair,
  				    struct spdk_nvmf_tcp_req *tcp_req);
  
  static void
  nvmf_tcp_req_set_state(struct spdk_nvmf_tcp_req *tcp_req,
  		       enum spdk_nvmf_tcp_req_state state)
  {
  	struct spdk_nvmf_qpair *qpair;
  	struct spdk_nvmf_tcp_qpair *tqpair;
  
  	qpair = tcp_req->req.qpair;
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  
  	assert(tqpair->state_cntr[tcp_req->state] > 0);
  	tqpair->state_cntr[tcp_req->state]--;
  	tqpair->state_cntr[state]++;
  
  	tcp_req->state = state;
  }
  
  static inline struct nvme_tcp_pdu *
  nvmf_tcp_req_pdu_init(struct spdk_nvmf_tcp_req *tcp_req)
  {
  	assert(tcp_req->pdu_in_use == false);
  	tcp_req->pdu_in_use = true;
  
  	memset(tcp_req->pdu, 0, sizeof(*tcp_req->pdu));
  	tcp_req->pdu->qpair = SPDK_CONTAINEROF(tcp_req->req.qpair, struct spdk_nvmf_tcp_qpair, qpair);
  
  	return tcp_req->pdu;
  }
  
  static inline void
  nvmf_tcp_req_pdu_fini(struct spdk_nvmf_tcp_req *tcp_req)
  {
  	tcp_req->pdu_in_use = false;
  }
  
  static struct spdk_nvmf_tcp_req *
  nvmf_tcp_req_get(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	struct spdk_nvmf_tcp_req *tcp_req;
  
  	tcp_req = TAILQ_FIRST(&tqpair->tcp_req_free_queue);
  	if (!tcp_req) {
  		return NULL;
  	}
  
  	memset(&tcp_req->rsp, 0, sizeof(tcp_req->rsp));
  	tcp_req->h2c_offset = 0;
  	tcp_req->has_incapsule_data = false;
  	tcp_req->req.dif.dif_insert_or_strip = false;
  
  	TAILQ_REMOVE(&tqpair->tcp_req_free_queue, tcp_req, state_link);
  	TAILQ_INSERT_TAIL(&tqpair->tcp_req_working_queue, tcp_req, state_link);
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_NEW);
  	return tcp_req;
  }
  
  static inline void
  nvmf_tcp_req_put(struct spdk_nvmf_tcp_qpair *tqpair, struct spdk_nvmf_tcp_req *tcp_req)
  {
  	TAILQ_REMOVE(&tqpair->tcp_req_working_queue, tcp_req, state_link);
  	TAILQ_INSERT_TAIL(&tqpair->tcp_req_free_queue, tcp_req, state_link);
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_FREE);
  }
  
  static void
  nvmf_tcp_request_free(void *cb_arg)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_tcp_req *tcp_req = cb_arg;
  
  	assert(tcp_req != NULL);
  
  	SPDK_DEBUGLOG(nvmf_tcp, "tcp_req=%p will be freed\n", tcp_req);
  	ttransport = SPDK_CONTAINEROF(tcp_req->req.qpair->transport,
  				      struct spdk_nvmf_tcp_transport, transport);
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_COMPLETED);
  	nvmf_tcp_req_process(ttransport, tcp_req);
  }
  
  static int
  nvmf_tcp_req_free(struct spdk_nvmf_request *req)
  {
  	struct spdk_nvmf_tcp_req *tcp_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_tcp_req, req);
  
  	nvmf_tcp_request_free(tcp_req);
  
  	return 0;
  }
  
  static void
  nvmf_tcp_drain_state_queue(struct spdk_nvmf_tcp_qpair *tqpair,
  			   enum spdk_nvmf_tcp_req_state state)
  {
  	struct spdk_nvmf_tcp_req *tcp_req, *req_tmp;
  
  	assert(state != TCP_REQUEST_STATE_FREE);
  	TAILQ_FOREACH_SAFE(tcp_req, &tqpair->tcp_req_working_queue, state_link, req_tmp) {
  		if (state == tcp_req->state) {
  			nvmf_tcp_request_free(tcp_req);
  		}
  	}
  }
  
  static void
  nvmf_tcp_cleanup_all_states(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	struct spdk_nvmf_tcp_req *tcp_req, *req_tmp;
  
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST);
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_NEW);
  
  	/* Wipe the requests waiting for buffer from the global list */
  	TAILQ_FOREACH_SAFE(tcp_req, &tqpair->tcp_req_working_queue, state_link, req_tmp) {
  		if (tcp_req->state == TCP_REQUEST_STATE_NEED_BUFFER) {
  			STAILQ_REMOVE(&tqpair->group->group.pending_buf_queue, &tcp_req->req,
  				      spdk_nvmf_request, buf_link);
  		}
  	}
  
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_NEED_BUFFER);
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_EXECUTING);
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER);
  	nvmf_tcp_drain_state_queue(tqpair, TCP_REQUEST_STATE_AWAITING_R2T_ACK);
  }
  
  static void
  nvmf_tcp_dump_qpair_req_contents(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	int i;
  	struct spdk_nvmf_tcp_req *tcp_req;
  
  	SPDK_ERRLOG("Dumping contents of queue pair (QID %d)\n", tqpair->qpair.qid);
  	for (i = 1; i < TCP_REQUEST_NUM_STATES; i++) {
  		SPDK_ERRLOG("\tNum of requests in state[%d] = %u\n", i, tqpair->state_cntr[i]);
  		TAILQ_FOREACH(tcp_req, &tqpair->tcp_req_working_queue, state_link) {
  			if ((int)tcp_req->state == i) {
  				SPDK_ERRLOG("\t\tRequest Data From Pool: %d\n", tcp_req->req.data_from_pool);
  				SPDK_ERRLOG("\t\tRequest opcode: %d\n", tcp_req->req.cmd->nvmf_cmd.opcode);
  			}
  		}
  	}
  }
  
  static void
  nvmf_tcp_qpair_destroy(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	int err = 0;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter\n");
  
  	err = spdk_sock_close(&tqpair->sock);
  	assert(err == 0);
  	nvmf_tcp_cleanup_all_states(tqpair);
  
  	if (tqpair->state_cntr[TCP_REQUEST_STATE_FREE] != tqpair->resource_count) {
  		SPDK_ERRLOG("tqpair(%p) free tcp request num is %u but should be %u\n", tqpair,
  			    tqpair->state_cntr[TCP_REQUEST_STATE_FREE],
  			    tqpair->resource_count);
  		err++;
  	}
  
  	if (err > 0) {
  		nvmf_tcp_dump_qpair_req_contents(tqpair);
  	}
  
  	spdk_dma_free(tqpair->pdus);
  	free(tqpair->reqs);
  	spdk_free(tqpair->bufs);
  	free(tqpair);
  	SPDK_DEBUGLOG(nvmf_tcp, "Leave\n");
  }
  
  static void
  nvmf_tcp_dump_opts(struct spdk_nvmf_transport *transport, struct spdk_json_write_ctx *w)
  {
  	struct spdk_nvmf_tcp_transport	*ttransport;
  	assert(w != NULL);
  
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  	spdk_json_write_named_bool(w, "c2h_success", ttransport->tcp_opts.c2h_success);
  	spdk_json_write_named_uint32(w, "sock_priority", ttransport->tcp_opts.sock_priority);
  }
  
  static int
  nvmf_tcp_destroy(struct spdk_nvmf_transport *transport,
  		 spdk_nvmf_transport_destroy_done_cb cb_fn, void *cb_arg)
  {
  	struct spdk_nvmf_tcp_transport	*ttransport;
  
  	assert(transport != NULL);
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  
  	pthread_mutex_destroy(&ttransport->lock);
  	free(ttransport);
  
  	if (cb_fn) {
  		cb_fn(cb_arg);
  	}
  	return 0;
  }
  
  static struct spdk_nvmf_transport *
  nvmf_tcp_create(struct spdk_nvmf_transport_opts *opts)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	uint32_t sge_count;
  	uint32_t min_shared_buffers;
  
  	ttransport = calloc(1, sizeof(*ttransport));
  	if (!ttransport) {
  		return NULL;
  	}
  
  	TAILQ_INIT(&ttransport->ports);
  
  	ttransport->transport.ops = &spdk_nvmf_transport_tcp;
  
  	ttransport->tcp_opts.c2h_success = SPDK_NVMF_TCP_DEFAULT_SUCCESS_OPTIMIZATION;
  	ttransport->tcp_opts.sock_priority = SPDK_NVMF_TCP_DEFAULT_SOCK_PRIORITY;
  	ttransport->tcp_opts.control_msg_num = SPDK_NVMF_TCP_DEFAULT_CONTROL_MSG_NUM;
  	if (opts->transport_specific != NULL &&
  	    spdk_json_decode_object_relaxed(opts->transport_specific, tcp_transport_opts_decoder,
  					    SPDK_COUNTOF(tcp_transport_opts_decoder),
  					    &ttransport->tcp_opts)) {
  		SPDK_ERRLOG("spdk_json_decode_object_relaxed failed\n");
  		free(ttransport);
  		return NULL;
  	}
  
  	SPDK_NOTICELOG("*** TCP Transport Init ***\n");
  
  	SPDK_INFOLOG(nvmf_tcp, "*** TCP Transport Init ***\n"
  		     "  Transport opts:  max_ioq_depth=%d, max_io_size=%d,\n"
  		     "  max_io_qpairs_per_ctrlr=%d, io_unit_size=%d,\n"
  		     "  in_capsule_data_size=%d, max_aq_depth=%d\n"
  		     "  num_shared_buffers=%d, c2h_success=%d,\n"
  		     "  dif_insert_or_strip=%d, sock_priority=%d\n"
  		     "  abort_timeout_sec=%d, control_msg_num=%hu\n",
  		     opts->max_queue_depth,
  		     opts->max_io_size,
  		     opts->max_qpairs_per_ctrlr - 1,
  		     opts->io_unit_size,
  		     opts->in_capsule_data_size,
  		     opts->max_aq_depth,
  		     opts->num_shared_buffers,
  		     ttransport->tcp_opts.c2h_success,
  		     opts->dif_insert_or_strip,
  		     ttransport->tcp_opts.sock_priority,
  		     opts->abort_timeout_sec,
  		     ttransport->tcp_opts.control_msg_num);
  
  	if (ttransport->tcp_opts.sock_priority > SPDK_NVMF_TCP_DEFAULT_MAX_SOCK_PRIORITY) {
  		SPDK_ERRLOG("Unsupported socket_priority=%d, the current range is: 0 to %d\n"
  			    "you can use man 7 socket to view the range of priority under SO_PRIORITY item\n",
  			    ttransport->tcp_opts.sock_priority, SPDK_NVMF_TCP_DEFAULT_MAX_SOCK_PRIORITY);
  		free(ttransport);
  		return NULL;
  	}
  
  	if (ttransport->tcp_opts.control_msg_num == 0 &&
  	    opts->in_capsule_data_size < SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE) {
  		SPDK_WARNLOG("TCP param control_msg_num can't be 0 if ICD is less than %u bytes. Using default value %u\n",
  			     SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE, SPDK_NVMF_TCP_DEFAULT_CONTROL_MSG_NUM);
  		ttransport->tcp_opts.control_msg_num = SPDK_NVMF_TCP_DEFAULT_CONTROL_MSG_NUM;
  	}
  
  	/* I/O unit size cannot be larger than max I/O size */
  	if (opts->io_unit_size > opts->max_io_size) {
  		opts->io_unit_size = opts->max_io_size;
  	}
  
  	sge_count = opts->max_io_size / opts->io_unit_size;
  	if (sge_count > SPDK_NVMF_MAX_SGL_ENTRIES) {
  		SPDK_ERRLOG("Unsupported IO Unit size specified, %d bytes\n", opts->io_unit_size);
  		free(ttransport);
  		return NULL;
  	}
  
  	min_shared_buffers = spdk_env_get_core_count() * opts->buf_cache_size;
  	if (min_shared_buffers > opts->num_shared_buffers) {
  		SPDK_ERRLOG("There are not enough buffers to satisfy"
  			    "per-poll group caches for each thread. (%" PRIu32 ")"
  			    "supplied. (%" PRIu32 ") required\n", opts->num_shared_buffers, min_shared_buffers);
  		SPDK_ERRLOG("Please specify a larger number of shared buffers\n");
  		nvmf_tcp_destroy(&ttransport->transport, NULL, NULL);
  		return NULL;
  	}
  
  	pthread_mutex_init(&ttransport->lock, NULL);
  
  	return &ttransport->transport;
  }
  
  static int
  nvmf_tcp_trsvcid_to_int(const char *trsvcid)
  {
  	unsigned long long ull;
  	char *end = NULL;
  
  	ull = strtoull(trsvcid, &end, 10);
  	if (end == NULL || end == trsvcid || *end != '\0') {
  		return -1;
  	}
  
  	/* Valid TCP/IP port numbers are in [0, 65535] */
  	if (ull > 65535) {
  		return -1;
  	}
  
  	return (int)ull;
  }
  
  /**
   * Canonicalize a listen address trid.
   */
  static int
  nvmf_tcp_canon_listen_trid(struct spdk_nvme_transport_id *canon_trid,
  			   const struct spdk_nvme_transport_id *trid)
  {
  	int trsvcid_int;
  
  	trsvcid_int = nvmf_tcp_trsvcid_to_int(trid->trsvcid);
  	if (trsvcid_int < 0) {
  		return -EINVAL;
  	}
  
  	memset(canon_trid, 0, sizeof(*canon_trid));
  	spdk_nvme_trid_populate_transport(canon_trid, SPDK_NVME_TRANSPORT_TCP);
  	canon_trid->adrfam = trid->adrfam;
  	snprintf(canon_trid->traddr, sizeof(canon_trid->traddr), "%s", trid->traddr);
  	snprintf(canon_trid->trsvcid, sizeof(canon_trid->trsvcid), "%d", trsvcid_int);
  
  	return 0;
  }
  
  /**
   * Find an existing listening port.
   *
   * Caller must hold ttransport->lock.
   */
  static struct spdk_nvmf_tcp_port *
  nvmf_tcp_find_port(struct spdk_nvmf_tcp_transport *ttransport,
  		   const struct spdk_nvme_transport_id *trid)
  {
  	struct spdk_nvme_transport_id canon_trid;
  	struct spdk_nvmf_tcp_port *port;
  
  	if (nvmf_tcp_canon_listen_trid(&canon_trid, trid) != 0) {
  		return NULL;
  	}
  
  	TAILQ_FOREACH(port, &ttransport->ports, link) {
  		if (spdk_nvme_transport_id_compare(&canon_trid, port->trid) == 0) {
  			return port;
  		}
  	}
  
  	return NULL;
  }
  
  static int
  nvmf_tcp_listen(struct spdk_nvmf_transport *transport, const struct spdk_nvme_transport_id *trid,
  		struct spdk_nvmf_listen_opts *listen_opts)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_tcp_port *port;
  	int trsvcid_int;
  	uint8_t adrfam;
  	struct spdk_sock_opts opts;
  
  	if (!strlen(trid->trsvcid)) {
  		SPDK_ERRLOG("Service id is required\n");
  		return -EINVAL;
  	}
  
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  
  	trsvcid_int = nvmf_tcp_trsvcid_to_int(trid->trsvcid);
  	if (trsvcid_int < 0) {
  		SPDK_ERRLOG("Invalid trsvcid '%s'\n", trid->trsvcid);
  		return -EINVAL;
  	}
  
  	pthread_mutex_lock(&ttransport->lock);
  	port = calloc(1, sizeof(*port));
  	if (!port) {
  		SPDK_ERRLOG("Port allocation failed\n");
  		pthread_mutex_unlock(&ttransport->lock);
  		return -ENOMEM;
  	}
  
  	port->trid = trid;
  	opts.opts_size = sizeof(opts);
  	spdk_sock_get_default_opts(&opts);
  	opts.priority = ttransport->tcp_opts.sock_priority;
  	port->listen_sock = spdk_sock_listen_ext(trid->traddr, trsvcid_int,
  			    NULL, &opts);
  	if (port->listen_sock == NULL) {
  		SPDK_ERRLOG("spdk_sock_listen(%s, %d) failed: %s (%d)\n",
  			    trid->traddr, trsvcid_int,
  			    spdk_strerror(errno), errno);
  		free(port);
  		pthread_mutex_unlock(&ttransport->lock);
  		return -errno;
  	}
  
  	if (spdk_sock_is_ipv4(port->listen_sock)) {
  		adrfam = SPDK_NVMF_ADRFAM_IPV4;
  	} else if (spdk_sock_is_ipv6(port->listen_sock)) {
  		adrfam = SPDK_NVMF_ADRFAM_IPV6;
  	} else {
  		SPDK_ERRLOG("Unhandled socket type\n");
  		adrfam = 0;
  	}
  
  	if (adrfam != trid->adrfam) {
  		SPDK_ERRLOG("Socket address family mismatch\n");
  		spdk_sock_close(&port->listen_sock);
  		free(port);
  		pthread_mutex_unlock(&ttransport->lock);
  		return -EINVAL;
  	}
  
  	SPDK_NOTICELOG("*** NVMe/TCP Target Listening on %s port %s ***\n",
  		       trid->traddr, trid->trsvcid);
  
  	TAILQ_INSERT_TAIL(&ttransport->ports, port, link);
  	pthread_mutex_unlock(&ttransport->lock);
  	return 0;
  }
  
  static void
  nvmf_tcp_stop_listen(struct spdk_nvmf_transport *transport,
  		     const struct spdk_nvme_transport_id *trid)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_tcp_port *port;
  
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  
  	SPDK_DEBUGLOG(nvmf_tcp, "Removing listen address %s port %s\n",
  		      trid->traddr, trid->trsvcid);
  
  	pthread_mutex_lock(&ttransport->lock);
  	port = nvmf_tcp_find_port(ttransport, trid);
  	if (port) {
  		TAILQ_REMOVE(&ttransport->ports, port, link);
  		spdk_sock_close(&port->listen_sock);
  		free(port);
  	}
  
  	pthread_mutex_unlock(&ttransport->lock);
  }
  
  static void nvmf_tcp_qpair_set_recv_state(struct spdk_nvmf_tcp_qpair *tqpair,
  		enum nvme_tcp_pdu_recv_state state);
  
  static void
  nvmf_tcp_qpair_disconnect(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	SPDK_DEBUGLOG(nvmf_tcp, "Disconnecting qpair %p\n", tqpair);
  
  	if (tqpair->state <= NVME_TCP_QPAIR_STATE_RUNNING) {
  		tqpair->state = NVME_TCP_QPAIR_STATE_EXITING;
  		nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_ERROR);
  		spdk_poller_unregister(&tqpair->timeout_poller);
  
  		/* This will end up calling nvmf_tcp_close_qpair */
  		spdk_nvmf_qpair_disconnect(&tqpair->qpair, NULL, NULL);
  	}
  }
  
  static void
  _pdu_write_done(void *_pdu, int err)
  {
  	struct nvme_tcp_pdu			*pdu = _pdu;
  	struct spdk_nvmf_tcp_qpair		*tqpair = pdu->qpair;
  
  	if (err != 0) {
  		nvmf_tcp_qpair_disconnect(tqpair);
  		return;
  	}
  
  	assert(pdu->cb_fn != NULL);
  	pdu->cb_fn(pdu->cb_arg);
  }
  
  static void
  _tcp_write_pdu(struct nvme_tcp_pdu *pdu)
  {
  	uint32_t mapped_length = 0;
  	ssize_t rc;
  	struct spdk_nvmf_tcp_qpair *tqpair = pdu->qpair;
  
  	pdu->sock_req.iovcnt = nvme_tcp_build_iovs(pdu->iov, SPDK_COUNTOF(pdu->iov), pdu,
  			       tqpair->host_hdgst_enable, tqpair->host_ddgst_enable,
  			       &mapped_length);
  	pdu->sock_req.cb_fn = _pdu_write_done;
  	pdu->sock_req.cb_arg = pdu;
  	if (pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_IC_RESP ||
  	    pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_C2H_TERM_REQ) {
  		rc = spdk_sock_writev(tqpair->sock, pdu->iov, pdu->sock_req.iovcnt);
  		if (rc == mapped_length) {
  			_pdu_write_done(pdu, 0);
  		} else {
  			SPDK_ERRLOG("IC_RESP or TERM_REQ could not write to socket.\n");
  			_pdu_write_done(pdu, -1);
  		}
  	} else {
  		spdk_sock_writev_async(tqpair->sock, &pdu->sock_req);
  	}
  }
  
  static void
  data_crc32_accel_done(void *cb_arg, int status)
  {
  	struct nvme_tcp_pdu *pdu = cb_arg;
  
  	if (spdk_unlikely(status)) {
  		SPDK_ERRLOG("Failed to compute the data digest for pdu =%p\n", pdu);
  		_pdu_write_done(pdu, status);
  		return;
  	}
  
  	pdu->data_digest_crc32 ^= SPDK_CRC32C_XOR;
  	MAKE_DIGEST_WORD(pdu->data_digest, pdu->data_digest_crc32);
  
  	_tcp_write_pdu(pdu);
  }
  
  static void
  pdu_data_crc32_compute(struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair = pdu->qpair;
  	uint32_t crc32c;
  
  	/* Data Digest */
  	if (pdu->data_len > 0 && g_nvme_tcp_ddgst[pdu->hdr.common.pdu_type] && tqpair->host_ddgst_enable) {
  		/* Only suport this limitated case for the first step */
  		if (spdk_likely(!pdu->dif_ctx && (pdu->data_len % SPDK_NVME_TCP_DIGEST_ALIGNMENT == 0)
  				&& tqpair->group)) {
  			spdk_accel_submit_crc32cv(tqpair->group->accel_channel, &pdu->data_digest_crc32,
  						  pdu->data_iov, pdu->data_iovcnt, 0, data_crc32_accel_done, pdu);
  			return;
  		}
  
  		crc32c = nvme_tcp_pdu_calc_data_digest(pdu);
  		MAKE_DIGEST_WORD(pdu->data_digest, crc32c);
  	}
  
  	_tcp_write_pdu(pdu);
  }
  
  static void
  header_crc32_accel_done(void *cb_arg, int status)
  {
  	struct nvme_tcp_pdu *pdu = cb_arg;
  
  	pdu->header_digest_crc32 ^= SPDK_CRC32C_XOR;
  	MAKE_DIGEST_WORD((uint8_t *)pdu->hdr.raw + pdu->hdr.common.hlen, pdu->header_digest_crc32);
  	if (spdk_unlikely(status)) {
  		SPDK_ERRLOG("Failed to compute header digest on pdu=%p\n", pdu);
  		_pdu_write_done(pdu, status);
  		return;
  	}
  
  	pdu_data_crc32_compute(pdu);
  }
  
  static void
  nvmf_tcp_qpair_write_pdu(struct spdk_nvmf_tcp_qpair *tqpair,
  			 struct nvme_tcp_pdu *pdu,
  			 nvme_tcp_qpair_xfer_complete_cb cb_fn,
  			 void *cb_arg)
  {
  	int hlen;
  
  	assert(&tqpair->pdu_in_progress != pdu);
  
  	hlen = pdu->hdr.common.hlen;
  	pdu->cb_fn = cb_fn;
  	pdu->cb_arg = cb_arg;
  	pdu->qpair = tqpair;
  
  	pdu->iov[0].iov_base = &pdu->hdr.raw;
  	pdu->iov[0].iov_len = hlen;
  
  	/* Header Digest */
  	if (g_nvme_tcp_hdgst[pdu->hdr.common.pdu_type] && tqpair->host_hdgst_enable && tqpair->group) {
  		spdk_accel_submit_crc32cv(tqpair->group->accel_channel, &pdu->header_digest_crc32,
  					  pdu->iov, 1, 0, header_crc32_accel_done, pdu);
  		return;
  	}
  
  	pdu_data_crc32_compute(pdu);
  }
  
  static int
  nvmf_tcp_qpair_init_mem_resource(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	uint32_t i;
  	struct spdk_nvmf_transport_opts *opts;
  	uint32_t in_capsule_data_size;
  
  	opts = &tqpair->qpair.transport->opts;
  
  	in_capsule_data_size = opts->in_capsule_data_size;
  	if (opts->dif_insert_or_strip) {
  		in_capsule_data_size = SPDK_BDEV_BUF_SIZE_WITH_MD(in_capsule_data_size);
  	}
  
  	tqpair->resource_count = opts->max_queue_depth;
  
  	tqpair->reqs = calloc(tqpair->resource_count, sizeof(*tqpair->reqs));
  	if (!tqpair->reqs) {
  		SPDK_ERRLOG("Unable to allocate reqs on tqpair=%p\n", tqpair);
  		return -1;
  	}
  
  	if (in_capsule_data_size) {
  		tqpair->bufs = spdk_zmalloc(tqpair->resource_count * in_capsule_data_size, 0x1000,
  					    NULL, SPDK_ENV_LCORE_ID_ANY,
  					    SPDK_MALLOC_DMA);
  		if (!tqpair->bufs) {
  			SPDK_ERRLOG("Unable to allocate bufs on tqpair=%p.\n", tqpair);
  			return -1;
  		}
  	}
  
  	/* Add addtional one member, which will be used for mgmt_pdu owned by the tqpair */
  	tqpair->pdus = spdk_dma_malloc((tqpair->resource_count + 1) * sizeof(*tqpair->pdus), 0x1000, NULL);
  	if (!tqpair->pdus) {
  		SPDK_ERRLOG("Unable to allocate pdu pool on tqpair =%p.\n", tqpair);
  		return -1;
  	}
  
  	for (i = 0; i < tqpair->resource_count; i++) {
  		struct spdk_nvmf_tcp_req *tcp_req = &tqpair->reqs[i];
  
  		tcp_req->ttag = i + 1;
  		tcp_req->req.qpair = &tqpair->qpair;
  
  		tcp_req->pdu = &tqpair->pdus[i];
  		tcp_req->pdu->qpair = tqpair;
  
  		/* Set up memory to receive commands */
  		if (tqpair->bufs) {
  			tcp_req->buf = (void *)((uintptr_t)tqpair->bufs + (i * in_capsule_data_size));
  		}
  
  		/* Set the cmdn and rsp */
  		tcp_req->req.rsp = (union nvmf_c2h_msg *)&tcp_req->rsp;
  		tcp_req->req.cmd = (union nvmf_h2c_msg *)&tcp_req->cmd;
  
  		/* Initialize request state to FREE */
  		tcp_req->state = TCP_REQUEST_STATE_FREE;
  		TAILQ_INSERT_TAIL(&tqpair->tcp_req_free_queue, tcp_req, state_link);
  		tqpair->state_cntr[TCP_REQUEST_STATE_FREE]++;
  	}
  
  	tqpair->mgmt_pdu = &tqpair->pdus[i];
  	tqpair->mgmt_pdu->qpair = tqpair;
  
  	tqpair->recv_buf_size = (in_capsule_data_size + sizeof(struct spdk_nvme_tcp_cmd) + 2 *
  				 SPDK_NVME_TCP_DIGEST_LEN) * SPDK_NVMF_TCP_RECV_BUF_SIZE_FACTOR;
  
  	return 0;
  }
  
  static int
  nvmf_tcp_qpair_init(struct spdk_nvmf_qpair *qpair)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair;
  
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  
  	SPDK_DEBUGLOG(nvmf_tcp, "New TCP Connection: %p\n", qpair);
  
  	/* Initialise request state queues of the qpair */
  	TAILQ_INIT(&tqpair->tcp_req_free_queue);
  	TAILQ_INIT(&tqpair->tcp_req_working_queue);
  
  	tqpair->host_hdgst_enable = true;
  	tqpair->host_ddgst_enable = true;
  
  	return 0;
  }
  
  static int
  nvmf_tcp_qpair_sock_init(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	int rc;
  
  	/* set low water mark */
  	rc = spdk_sock_set_recvlowat(tqpair->sock, sizeof(struct spdk_nvme_tcp_common_pdu_hdr));
  	if (rc != 0) {
  		SPDK_ERRLOG("spdk_sock_set_recvlowat() failed\n");
  		return rc;
  	}
  
  	return 0;
  }
  
  static void
  nvmf_tcp_handle_connect(struct spdk_nvmf_transport *transport,
  			struct spdk_nvmf_tcp_port *port,
  			struct spdk_sock *sock)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair;
  	int rc;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "New connection accepted on %s port %s\n",
  		      port->trid->traddr, port->trid->trsvcid);
  
  	tqpair = calloc(1, sizeof(struct spdk_nvmf_tcp_qpair));
  	if (tqpair == NULL) {
  		SPDK_ERRLOG("Could not allocate new connection.\n");
  		spdk_sock_close(&sock);
  		return;
  	}
  
  	tqpair->sock = sock;
  	tqpair->state_cntr[TCP_REQUEST_STATE_FREE] = 0;
  	tqpair->port = port;
  	tqpair->qpair.transport = transport;
  
  	rc = spdk_sock_getaddr(tqpair->sock, tqpair->target_addr,
  			       sizeof(tqpair->target_addr), &tqpair->target_port,
  			       tqpair->initiator_addr, sizeof(tqpair->initiator_addr),
  			       &tqpair->initiator_port);
  	if (rc < 0) {
  		SPDK_ERRLOG("spdk_sock_getaddr() failed of tqpair=%p\n", tqpair);
  		nvmf_tcp_qpair_destroy(tqpair);
  		return;
  	}
  
  	spdk_nvmf_tgt_new_qpair(transport->tgt, &tqpair->qpair);
  }
  
  static uint32_t
  nvmf_tcp_port_accept(struct spdk_nvmf_transport *transport, struct spdk_nvmf_tcp_port *port)
  {
  	struct spdk_sock *sock;
  	uint32_t count = 0;
  	int i;
  
  	for (i = 0; i < NVMF_TCP_MAX_ACCEPT_SOCK_ONE_TIME; i++) {
  		sock = spdk_sock_accept(port->listen_sock);
  		if (sock == NULL) {
  			break;
  		}
  		count++;
  		nvmf_tcp_handle_connect(transport, port, sock);
  	}
  
  	return count;
  }
  
  static uint32_t
  nvmf_tcp_accept(struct spdk_nvmf_transport *transport)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_tcp_port *port;
  	uint32_t count = 0;
  
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  
  	TAILQ_FOREACH(port, &ttransport->ports, link) {
  		count += nvmf_tcp_port_accept(transport, port);
  	}
  
  	return count;
  }
  
  static void
  nvmf_tcp_discover(struct spdk_nvmf_transport *transport,
  		  struct spdk_nvme_transport_id *trid,
  		  struct spdk_nvmf_discovery_log_page_entry *entry)
  {
  	entry->trtype = SPDK_NVMF_TRTYPE_TCP;
  	entry->adrfam = trid->adrfam;
  	entry->treq.secure_channel = SPDK_NVMF_TREQ_SECURE_CHANNEL_NOT_REQUIRED;
  
  	spdk_strcpy_pad(entry->trsvcid, trid->trsvcid, sizeof(entry->trsvcid), ' ');
  	spdk_strcpy_pad(entry->traddr, trid->traddr, sizeof(entry->traddr), ' ');
  
  	entry->tsas.tcp.sectype = SPDK_NVME_TCP_SECURITY_NONE;
  }
  
  static struct spdk_nvmf_tcp_control_msg_list *
  nvmf_tcp_control_msg_list_create(uint16_t num_messages)
  {
  	struct spdk_nvmf_tcp_control_msg_list *list;
  	struct spdk_nvmf_tcp_control_msg *msg;
  	uint16_t i;
  
  	list = calloc(1, sizeof(*list));
  	if (!list) {
  		SPDK_ERRLOG("Failed to allocate memory for list structure\n");
  		return NULL;
  	}
  
  	list->msg_buf = spdk_zmalloc(num_messages * SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE,
  				     NVMF_DATA_BUFFER_ALIGNMENT, NULL, SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_DMA);
  	if (!list->msg_buf) {
  		SPDK_ERRLOG("Failed to allocate memory for control message buffers\n");
  		free(list);
  		return NULL;
  	}
  
  	STAILQ_INIT(&list->free_msgs);
  
  	for (i = 0; i < num_messages; i++) {
  		msg = (struct spdk_nvmf_tcp_control_msg *)((char *)list->msg_buf + i *
  				SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE);
  		STAILQ_INSERT_TAIL(&list->free_msgs, msg, link);
  	}
  
  	return list;
  }
  
  static void
  nvmf_tcp_control_msg_list_free(struct spdk_nvmf_tcp_control_msg_list *list)
  {
  	if (!list) {
  		return;
  	}
  
  	spdk_free(list->msg_buf);
  	free(list);
  }
  
  static struct spdk_nvmf_transport_poll_group *
  nvmf_tcp_poll_group_create(struct spdk_nvmf_transport *transport)
  {
  	struct spdk_nvmf_tcp_transport	*ttransport;
  	struct spdk_nvmf_tcp_poll_group *tgroup;
  
  	tgroup = calloc(1, sizeof(*tgroup));
  	if (!tgroup) {
  		return NULL;
  	}
  
  	tgroup->sock_group = spdk_sock_group_create(&tgroup->group);
  	if (!tgroup->sock_group) {
  		goto cleanup;
  	}
  
  	TAILQ_INIT(&tgroup->qpairs);
  	TAILQ_INIT(&tgroup->await_req);
  
  	ttransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_tcp_transport, transport);
  
  	if (transport->opts.in_capsule_data_size < SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE) {
  		SPDK_DEBUGLOG(nvmf_tcp, "ICD %u is less than min required for admin/fabric commands (%u). "
  			      "Creating control messages list\n", transport->opts.in_capsule_data_size,
  			      SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE);
  		tgroup->control_msg_list = nvmf_tcp_control_msg_list_create(ttransport->tcp_opts.control_msg_num);
  		if (!tgroup->control_msg_list) {
  			goto cleanup;
  		}
  	}
  
  	tgroup->accel_channel = spdk_accel_engine_get_io_channel();
  	if (spdk_unlikely(!tgroup->accel_channel)) {
  		SPDK_ERRLOG("Cannot create accel_channel for tgroup=%p\n", tgroup);
  		goto cleanup;
  	}
  
  	return &tgroup->group;
  
  cleanup:
  	nvmf_tcp_poll_group_destroy(&tgroup->group);
  	return NULL;
  }
  
  static struct spdk_nvmf_transport_poll_group *
  nvmf_tcp_get_optimal_poll_group(struct spdk_nvmf_qpair *qpair)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair;
  	struct spdk_sock_group *group = NULL;
  	int rc;
  
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	rc = spdk_sock_get_optimal_sock_group(tqpair->sock, &group);
  	if (!rc && group != NULL) {
  		return spdk_sock_group_get_ctx(group);
  	}
  
  	return NULL;
  }
  
  static void
  nvmf_tcp_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group)
  {
  	struct spdk_nvmf_tcp_poll_group *tgroup;
  
  	tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  	spdk_sock_group_close(&tgroup->sock_group);
  	if (tgroup->control_msg_list) {
  		nvmf_tcp_control_msg_list_free(tgroup->control_msg_list);
  	}
  
  	if (tgroup->accel_channel) {
  		spdk_put_io_channel(tgroup->accel_channel);
  	}
  
  	free(tgroup);
  }
  
  static void
  nvmf_tcp_qpair_set_recv_state(struct spdk_nvmf_tcp_qpair *tqpair,
  			      enum nvme_tcp_pdu_recv_state state)
  {
  	if (tqpair->recv_state == state) {
  		SPDK_ERRLOG("The recv state of tqpair=%p is same with the state(%d) to be set\n",
  			    tqpair, state);
  		return;
  	}
  
  	if (tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_REQ) {
  		/* When leaving the await req state, move the qpair to the main list */
  		TAILQ_REMOVE(&tqpair->group->await_req, tqpair, link);
  		TAILQ_INSERT_TAIL(&tqpair->group->qpairs, tqpair, link);
  	}
  
  	SPDK_DEBUGLOG(nvmf_tcp, "tqpair(%p) recv state=%d\n", tqpair, state);
  	tqpair->recv_state = state;
  
  	switch (state) {
  	case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_CH:
  	case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PSH:
  	case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD:
  		break;
  	case NVME_TCP_PDU_RECV_STATE_AWAIT_REQ:
  		TAILQ_REMOVE(&tqpair->group->qpairs, tqpair, link);
  		TAILQ_INSERT_TAIL(&tqpair->group->await_req, tqpair, link);
  		break;
  	case NVME_TCP_PDU_RECV_STATE_ERROR:
  	case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY:
  		memset(&tqpair->pdu_in_progress, 0, sizeof(tqpair->pdu_in_progress));
  		break;
  	default:
  		SPDK_ERRLOG("The state(%d) is invalid\n", state);
  		abort();
  		break;
  	}
  }
  
  static int
  nvmf_tcp_qpair_handle_timeout(void *ctx)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair = ctx;
  
  	assert(tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_ERROR);
  
  	SPDK_ERRLOG("No pdu coming for tqpair=%p within %d seconds\n", tqpair,
  		    SPDK_NVME_TCP_QPAIR_EXIT_TIMEOUT);
  
  	nvmf_tcp_qpair_disconnect(tqpair);
  	return SPDK_POLLER_BUSY;
  }
  
  static void
  nvmf_tcp_send_c2h_term_req_complete(void *cb_arg)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair = (struct spdk_nvmf_tcp_qpair *)cb_arg;
  
  	if (!tqpair->timeout_poller) {
  		tqpair->timeout_poller = SPDK_POLLER_REGISTER(nvmf_tcp_qpair_handle_timeout, tqpair,
  					 SPDK_NVME_TCP_QPAIR_EXIT_TIMEOUT * 1000000);
  	}
  }
  
  static void
  nvmf_tcp_send_c2h_term_req(struct spdk_nvmf_tcp_qpair *tqpair, struct nvme_tcp_pdu *pdu,
  			   enum spdk_nvme_tcp_term_req_fes fes, uint32_t error_offset)
  {
  	struct nvme_tcp_pdu *rsp_pdu;
  	struct spdk_nvme_tcp_term_req_hdr *c2h_term_req;
  	uint32_t c2h_term_req_hdr_len = sizeof(*c2h_term_req);
  	uint32_t copy_len;
  
  	rsp_pdu = tqpair->mgmt_pdu;
  
  	c2h_term_req = &rsp_pdu->hdr.term_req;
  	c2h_term_req->common.pdu_type = SPDK_NVME_TCP_PDU_TYPE_C2H_TERM_REQ;
  	c2h_term_req->common.hlen = c2h_term_req_hdr_len;
  
  	if ((fes == SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD) ||
  	    (fes == SPDK_NVME_TCP_TERM_REQ_FES_INVALID_DATA_UNSUPPORTED_PARAMETER)) {
  		DSET32(&c2h_term_req->fei, error_offset);
  	}
  
  	copy_len = spdk_min(pdu->hdr.common.hlen, SPDK_NVME_TCP_TERM_REQ_ERROR_DATA_MAX_SIZE);
  
  	/* Copy the error info into the buffer */
  	memcpy((uint8_t *)rsp_pdu->hdr.raw + c2h_term_req_hdr_len, pdu->hdr.raw, copy_len);
  	nvme_tcp_pdu_set_data(rsp_pdu, (uint8_t *)rsp_pdu->hdr.raw + c2h_term_req_hdr_len, copy_len);
  
  	/* Contain the header of the wrong received pdu */
  	c2h_term_req->common.plen = c2h_term_req->common.hlen + copy_len;
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_ERROR);
  	nvmf_tcp_qpair_write_pdu(tqpair, rsp_pdu, nvmf_tcp_send_c2h_term_req_complete, tqpair);
  }
  
  static void
  nvmf_tcp_capsule_cmd_hdr_handle(struct spdk_nvmf_tcp_transport *ttransport,
  				struct spdk_nvmf_tcp_qpair *tqpair,
  				struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvmf_tcp_req *tcp_req;
  
  	assert(pdu->psh_valid_bytes == pdu->psh_len);
  	assert(pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_CAPSULE_CMD);
  
  	tcp_req = nvmf_tcp_req_get(tqpair);
  	if (!tcp_req) {
  		/* Directly return and make the allocation retry again */
  		if (tqpair->state_cntr[TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST] > 0) {
  			return;
  		}
  
  		/* The host sent more commands than the maximum queue depth. */
  		SPDK_ERRLOG("Cannot allocate tcp_req on tqpair=%p\n", tqpair);
  		nvmf_tcp_qpair_disconnect(tqpair);
  		return;
  	}
  
  	pdu->req = tcp_req;
  	assert(tcp_req->state == TCP_REQUEST_STATE_NEW);
  	nvmf_tcp_req_process(ttransport, tcp_req);
  }
  
  static void
  nvmf_tcp_capsule_cmd_payload_handle(struct spdk_nvmf_tcp_transport *ttransport,
  				    struct spdk_nvmf_tcp_qpair *tqpair,
  				    struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvmf_tcp_req *tcp_req;
  	struct spdk_nvme_tcp_cmd *capsule_cmd;
  	uint32_t error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  
  	capsule_cmd = &pdu->hdr.capsule_cmd;
  	tcp_req = pdu->req;
  	assert(tcp_req != NULL);
  	if (capsule_cmd->common.pdo > SPDK_NVME_TCP_PDU_PDO_MAX_OFFSET) {
  		SPDK_ERRLOG("Expected ICReq capsule_cmd pdu offset <= %d, got %c\n",
  			    SPDK_NVME_TCP_PDU_PDO_MAX_OFFSET, capsule_cmd->common.pdo);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_common_pdu_hdr, pdo);
  		goto err;
  	}
  
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY);
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_EXECUTE);
  	nvmf_tcp_req_process(ttransport, tcp_req);
  
  	return;
  err:
  	nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  }
  
  static int
  nvmf_tcp_find_req_in_state(struct spdk_nvmf_tcp_qpair *tqpair,
  			   enum spdk_nvmf_tcp_req_state state,
  			   uint16_t cid, uint16_t tag,
  			   struct spdk_nvmf_tcp_req **req)
  {
  	struct spdk_nvmf_tcp_req *tcp_req = NULL;
  
  	TAILQ_FOREACH(tcp_req, &tqpair->tcp_req_working_queue, state_link) {
  		if (tcp_req->state != state) {
  			continue;
  		}
  
  		if (tcp_req->req.cmd->nvme_cmd.cid != cid) {
  			continue;
  		}
  
  		if (tcp_req->ttag == tag) {
  			*req = tcp_req;
  			return 0;
  		}
  
  		*req = NULL;
  		return -1;
  	}
  
  	/* Didn't find it, but not an error */
  	*req = NULL;
  	return 0;
  }
  
  static void
  nvmf_tcp_h2c_data_hdr_handle(struct spdk_nvmf_tcp_transport *ttransport,
  			     struct spdk_nvmf_tcp_qpair *tqpair,
  			     struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvmf_tcp_req *tcp_req;
  	uint32_t error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes = 0;
  	struct spdk_nvme_tcp_h2c_data_hdr *h2c_data;
  	int rc;
  
  	h2c_data = &pdu->hdr.h2c_data;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "tqpair=%p, r2t_info: datao=%u, datal=%u, cccid=%u, ttag=%u\n",
  		      tqpair, h2c_data->datao, h2c_data->datal, h2c_data->cccid, h2c_data->ttag);
  
  	rc = nvmf_tcp_find_req_in_state(tqpair, TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
  					h2c_data->cccid, h2c_data->ttag, &tcp_req);
  	if (rc == 0 && tcp_req == NULL) {
  		rc = nvmf_tcp_find_req_in_state(tqpair, TCP_REQUEST_STATE_AWAITING_R2T_ACK, h2c_data->cccid,
  						h2c_data->ttag, &tcp_req);
  	}
  
  	if (!tcp_req) {
  		SPDK_DEBUGLOG(nvmf_tcp, "tcp_req is not found for tqpair=%p\n", tqpair);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_DATA_UNSUPPORTED_PARAMETER;
  		if (rc == 0) {
  			error_offset = offsetof(struct spdk_nvme_tcp_h2c_data_hdr, cccid);
  		} else {
  			error_offset = offsetof(struct spdk_nvme_tcp_h2c_data_hdr, ttag);
  		}
  		goto err;
  	}
  
  	if (tcp_req->h2c_offset != h2c_data->datao) {
  		SPDK_DEBUGLOG(nvmf_tcp,
  			      "tcp_req(%p), tqpair=%p, expected data offset %u, but data offset is %u\n",
  			      tcp_req, tqpair, tcp_req->h2c_offset, h2c_data->datao);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_DATA_TRANSFER_OUT_OF_RANGE;
  		goto err;
  	}
  
  	if ((h2c_data->datao + h2c_data->datal) > tcp_req->req.length) {
  		SPDK_DEBUGLOG(nvmf_tcp,
  			      "tcp_req(%p), tqpair=%p,  (datao=%u + datal=%u) execeeds requested length=%u\n",
  			      tcp_req, tqpair, h2c_data->datao, h2c_data->datal, tcp_req->req.length);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_DATA_TRANSFER_OUT_OF_RANGE;
  		goto err;
  	}
  
  	pdu->req = tcp_req;
  
  	if (spdk_unlikely(tcp_req->req.dif.dif_insert_or_strip)) {
  		pdu->dif_ctx = &tcp_req->req.dif.dif_ctx;
  	}
  
  	nvme_tcp_pdu_set_data_buf(pdu, tcp_req->req.iov, tcp_req->req.iovcnt,
  				  h2c_data->datao, h2c_data->datal);
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD);
  	return;
  
  err:
  	nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  }
  
  static void
  nvmf_tcp_send_capsule_resp_pdu(struct spdk_nvmf_tcp_req *tcp_req,
  			       struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	struct nvme_tcp_pdu *rsp_pdu;
  	struct spdk_nvme_tcp_rsp *capsule_resp;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter, tqpair=%p\n", tqpair);
  
  	rsp_pdu = nvmf_tcp_req_pdu_init(tcp_req);
  	assert(rsp_pdu != NULL);
  
  	capsule_resp = &rsp_pdu->hdr.capsule_resp;
  	capsule_resp->common.pdu_type = SPDK_NVME_TCP_PDU_TYPE_CAPSULE_RESP;
  	capsule_resp->common.plen = capsule_resp->common.hlen = sizeof(*capsule_resp);
  	capsule_resp->rccqe = tcp_req->req.rsp->nvme_cpl;
  	if (tqpair->host_hdgst_enable) {
  		capsule_resp->common.flags |= SPDK_NVME_TCP_CH_FLAGS_HDGSTF;
  		capsule_resp->common.plen += SPDK_NVME_TCP_DIGEST_LEN;
  	}
  
  	nvmf_tcp_qpair_write_pdu(tqpair, rsp_pdu, nvmf_tcp_request_free, tcp_req);
  }
  
  static void
  nvmf_tcp_pdu_c2h_data_complete(void *cb_arg)
  {
  	struct spdk_nvmf_tcp_req *tcp_req = cb_arg;
  	struct spdk_nvmf_tcp_qpair *tqpair = SPDK_CONTAINEROF(tcp_req->req.qpair,
  					     struct spdk_nvmf_tcp_qpair, qpair);
  	struct spdk_nvmf_tcp_transport *ttransport = SPDK_CONTAINEROF(
  				tcp_req->req.qpair->transport, struct spdk_nvmf_tcp_transport, transport);
  
  	assert(tqpair != NULL);
  
  	if (spdk_unlikely(tcp_req->pdu->rw_offset < tcp_req->req.length)) {
  		SPDK_DEBUGLOG(nvmf_tcp, "sending another C2H part, offset %u length %u\n", tcp_req->pdu->rw_offset,
  			      tcp_req->req.length);
  		_nvmf_tcp_send_c2h_data(tqpair, tcp_req);
  		return;
  	}
  
  	if (ttransport->tcp_opts.c2h_success) {
  		nvmf_tcp_request_free(tcp_req);
  	} else {
  		nvmf_tcp_req_pdu_fini(tcp_req);
  		nvmf_tcp_send_capsule_resp_pdu(tcp_req, tqpair);
  	}
  }
  
  static void
  nvmf_tcp_r2t_complete(void *cb_arg)
  {
  	struct spdk_nvmf_tcp_req *tcp_req = cb_arg;
  	struct spdk_nvmf_tcp_transport *ttransport;
  
  	nvmf_tcp_req_pdu_fini(tcp_req);
  
  	ttransport = SPDK_CONTAINEROF(tcp_req->req.qpair->transport,
  				      struct spdk_nvmf_tcp_transport, transport);
  
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER);
  
  	if (tcp_req->h2c_offset == tcp_req->req.length) {
  		nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_EXECUTE);
  		nvmf_tcp_req_process(ttransport, tcp_req);
  	}
  }
  
  static void
  nvmf_tcp_send_r2t_pdu(struct spdk_nvmf_tcp_qpair *tqpair,
  		      struct spdk_nvmf_tcp_req *tcp_req)
  {
  	struct nvme_tcp_pdu *rsp_pdu;
  	struct spdk_nvme_tcp_r2t_hdr *r2t;
  
  	rsp_pdu = nvmf_tcp_req_pdu_init(tcp_req);
  	assert(rsp_pdu != NULL);
  
  	r2t = &rsp_pdu->hdr.r2t;
  	r2t->common.pdu_type = SPDK_NVME_TCP_PDU_TYPE_R2T;
  	r2t->common.plen = r2t->common.hlen = sizeof(*r2t);
  
  	if (tqpair->host_hdgst_enable) {
  		r2t->common.flags |= SPDK_NVME_TCP_CH_FLAGS_HDGSTF;
  		r2t->common.plen += SPDK_NVME_TCP_DIGEST_LEN;
  	}
  
  	r2t->cccid = tcp_req->req.cmd->nvme_cmd.cid;
  	r2t->ttag = tcp_req->ttag;
  	r2t->r2to = tcp_req->h2c_offset;
  	r2t->r2tl = tcp_req->req.length;
  
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_AWAITING_R2T_ACK);
  
  	SPDK_DEBUGLOG(nvmf_tcp,
  		      "tcp_req(%p) on tqpair(%p), r2t_info: cccid=%u, ttag=%u, r2to=%u, r2tl=%u\n",
  		      tcp_req, tqpair, r2t->cccid, r2t->ttag, r2t->r2to, r2t->r2tl);
  	nvmf_tcp_qpair_write_pdu(tqpair, rsp_pdu, nvmf_tcp_r2t_complete, tcp_req);
  }
  
  static void
  nvmf_tcp_h2c_data_payload_handle(struct spdk_nvmf_tcp_transport *ttransport,
  				 struct spdk_nvmf_tcp_qpair *tqpair,
  				 struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvmf_tcp_req *tcp_req;
  
  	tcp_req = pdu->req;
  	assert(tcp_req != NULL);
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter\n");
  
  	tcp_req->h2c_offset += pdu->data_len;
  
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY);
  
  	/* Wait for all of the data to arrive AND for the initial R2T PDU send to be
  	 * acknowledged before moving on. */
  	if (tcp_req->h2c_offset == tcp_req->req.length &&
  	    tcp_req->state == TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER) {
  		nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_EXECUTE);
  		nvmf_tcp_req_process(ttransport, tcp_req);
  	}
  }
  
  static void
  nvmf_tcp_h2c_term_req_dump(struct spdk_nvme_tcp_term_req_hdr *h2c_term_req)
  {
  	SPDK_ERRLOG("Error info of pdu(%p): %s\n", h2c_term_req,
  		    spdk_nvmf_tcp_term_req_fes_str[h2c_term_req->fes]);
  	if ((h2c_term_req->fes == SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD) ||
  	    (h2c_term_req->fes == SPDK_NVME_TCP_TERM_REQ_FES_INVALID_DATA_UNSUPPORTED_PARAMETER)) {
  		SPDK_DEBUGLOG(nvmf_tcp, "The offset from the start of the PDU header is %u\n",
  			      DGET32(h2c_term_req->fei));
  	}
  }
  
  static void
  nvmf_tcp_h2c_term_req_hdr_handle(struct spdk_nvmf_tcp_qpair *tqpair,
  				 struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvme_tcp_term_req_hdr *h2c_term_req = &pdu->hdr.term_req;
  	uint32_t error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  
  	if (h2c_term_req->fes > SPDK_NVME_TCP_TERM_REQ_FES_INVALID_DATA_UNSUPPORTED_PARAMETER) {
  		SPDK_ERRLOG("Fatal Error Status(FES) is unknown for h2c_term_req pdu=%p\n", pdu);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_term_req_hdr, fes);
  		goto end;
  	}
  
  	/* set the data buffer */
  	nvme_tcp_pdu_set_data(pdu, (uint8_t *)pdu->hdr.raw + h2c_term_req->common.hlen,
  			      h2c_term_req->common.plen - h2c_term_req->common.hlen);
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD);
  	return;
  end:
  	nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  }
  
  static void
  nvmf_tcp_h2c_term_req_payload_handle(struct spdk_nvmf_tcp_qpair *tqpair,
  				     struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvme_tcp_term_req_hdr *h2c_term_req = &pdu->hdr.term_req;
  
  	nvmf_tcp_h2c_term_req_dump(h2c_term_req);
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_ERROR);
  }
  
  static void
  nvmf_tcp_pdu_payload_handle(struct spdk_nvmf_tcp_qpair *tqpair,
  			    struct spdk_nvmf_tcp_transport *ttransport)
  {
  	int rc = 0;
  	struct nvme_tcp_pdu *pdu;
  	uint32_t crc32c, error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  
  	assert(tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD);
  	pdu = &tqpair->pdu_in_progress;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter\n");
  	/* check data digest if need */
  	if (pdu->ddgst_enable) {
  		crc32c = nvme_tcp_pdu_calc_data_digest(pdu);
  		rc = MATCH_DIGEST_WORD(pdu->data_digest, crc32c);
  		if (rc == 0) {
  			SPDK_ERRLOG("Data digest error on tqpair=(%p) with pdu=%p\n", tqpair, pdu);
  			fes = SPDK_NVME_TCP_TERM_REQ_FES_HDGST_ERROR;
  			nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  			return;
  
  		}
  	}
  
  	switch (pdu->hdr.common.pdu_type) {
  	case SPDK_NVME_TCP_PDU_TYPE_CAPSULE_CMD:
  		nvmf_tcp_capsule_cmd_payload_handle(ttransport, tqpair, pdu);
  		break;
  	case SPDK_NVME_TCP_PDU_TYPE_H2C_DATA:
  		nvmf_tcp_h2c_data_payload_handle(ttransport, tqpair, pdu);
  		break;
  
  	case SPDK_NVME_TCP_PDU_TYPE_H2C_TERM_REQ:
  		nvmf_tcp_h2c_term_req_payload_handle(tqpair, pdu);
  		break;
  
  	default:
  		/* The code should not go to here */
  		SPDK_ERRLOG("The code should not go to here\n");
  		break;
  	}
  }
  
  static void
  nvmf_tcp_send_icresp_complete(void *cb_arg)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair = cb_arg;
  
  	tqpair->state = NVME_TCP_QPAIR_STATE_RUNNING;
  }
  
  static void
  nvmf_tcp_icreq_handle(struct spdk_nvmf_tcp_transport *ttransport,
  		      struct spdk_nvmf_tcp_qpair *tqpair,
  		      struct nvme_tcp_pdu *pdu)
  {
  	struct spdk_nvme_tcp_ic_req *ic_req = &pdu->hdr.ic_req;
  	struct nvme_tcp_pdu *rsp_pdu;
  	struct spdk_nvme_tcp_ic_resp *ic_resp;
  	uint32_t error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  
  	/* Only PFV 0 is defined currently */
  	if (ic_req->pfv != 0) {
  		SPDK_ERRLOG("Expected ICReq PFV %u, got %u\n", 0u, ic_req->pfv);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_ic_req, pfv);
  		goto end;
  	}
  
  	/* MAXR2T is 0's based */
  	SPDK_DEBUGLOG(nvmf_tcp, "maxr2t =%u\n", (ic_req->maxr2t + 1u));
  
  	tqpair->host_hdgst_enable = ic_req->dgst.bits.hdgst_enable ? true : false;
  	if (!tqpair->host_hdgst_enable) {
  		tqpair->recv_buf_size -= SPDK_NVME_TCP_DIGEST_LEN * SPDK_NVMF_TCP_RECV_BUF_SIZE_FACTOR;
  	}
  
  	tqpair->host_ddgst_enable = ic_req->dgst.bits.ddgst_enable ? true : false;
  	if (!tqpair->host_ddgst_enable) {
  		tqpair->recv_buf_size -= SPDK_NVME_TCP_DIGEST_LEN * SPDK_NVMF_TCP_RECV_BUF_SIZE_FACTOR;
  	}
  
  	tqpair->recv_buf_size = spdk_max(tqpair->recv_buf_size, MIN_SOCK_PIPE_SIZE);
  	/* Now that we know whether digests are enabled, properly size the receive buffer */
  	if (spdk_sock_set_recvbuf(tqpair->sock, tqpair->recv_buf_size) < 0) {
  		SPDK_WARNLOG("Unable to allocate enough memory for receive buffer on tqpair=%p with size=%d\n",
  			     tqpair,
  			     tqpair->recv_buf_size);
  		/* Not fatal. */
  	}
  
  	tqpair->cpda = spdk_min(ic_req->hpda, SPDK_NVME_TCP_CPDA_MAX);
  	SPDK_DEBUGLOG(nvmf_tcp, "cpda of tqpair=(%p) is : %u\n", tqpair, tqpair->cpda);
  
  	rsp_pdu = tqpair->mgmt_pdu;
  
  	ic_resp = &rsp_pdu->hdr.ic_resp;
  	ic_resp->common.pdu_type = SPDK_NVME_TCP_PDU_TYPE_IC_RESP;
  	ic_resp->common.hlen = ic_resp->common.plen =  sizeof(*ic_resp);
  	ic_resp->pfv = 0;
  	ic_resp->cpda = tqpair->cpda;
  	ic_resp->maxh2cdata = ttransport->transport.opts.max_io_size;
  	ic_resp->dgst.bits.hdgst_enable = tqpair->host_hdgst_enable ? 1 : 0;
  	ic_resp->dgst.bits.ddgst_enable = tqpair->host_ddgst_enable ? 1 : 0;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "host_hdgst_enable: %u\n", tqpair->host_hdgst_enable);
  	SPDK_DEBUGLOG(nvmf_tcp, "host_ddgst_enable: %u\n", tqpair->host_ddgst_enable);
  
  	tqpair->state = NVME_TCP_QPAIR_STATE_INITIALIZING;
  	nvmf_tcp_qpair_write_pdu(tqpair, rsp_pdu, nvmf_tcp_send_icresp_complete, tqpair);
  	nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY);
  	return;
  end:
  	nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  }
  
  static void
  nvmf_tcp_pdu_psh_handle(struct spdk_nvmf_tcp_qpair *tqpair,
  			struct spdk_nvmf_tcp_transport *ttransport)
  {
  	struct nvme_tcp_pdu *pdu;
  	int rc;
  	uint32_t crc32c, error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  
  	assert(tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PSH);
  	pdu = &tqpair->pdu_in_progress;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "pdu type of tqpair(%p) is %d\n", tqpair,
  		      pdu->hdr.common.pdu_type);
  	/* check header digest if needed */
  	if (pdu->has_hdgst) {
  		SPDK_DEBUGLOG(nvmf_tcp, "Compare the header of pdu=%p on tqpair=%p\n", pdu, tqpair);
  		crc32c = nvme_tcp_pdu_calc_header_digest(pdu);
  		rc = MATCH_DIGEST_WORD((uint8_t *)pdu->hdr.raw + pdu->hdr.common.hlen, crc32c);
  		if (rc == 0) {
  			SPDK_ERRLOG("Header digest error on tqpair=(%p) with pdu=%p\n", tqpair, pdu);
  			fes = SPDK_NVME_TCP_TERM_REQ_FES_HDGST_ERROR;
  			nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  			return;
  
  		}
  	}
  
  	switch (pdu->hdr.common.pdu_type) {
  	case SPDK_NVME_TCP_PDU_TYPE_IC_REQ:
  		nvmf_tcp_icreq_handle(ttransport, tqpair, pdu);
  		break;
  	case SPDK_NVME_TCP_PDU_TYPE_CAPSULE_CMD:
  		nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_REQ);
  		break;
  	case SPDK_NVME_TCP_PDU_TYPE_H2C_DATA:
  		nvmf_tcp_h2c_data_hdr_handle(ttransport, tqpair, pdu);
  		break;
  
  	case SPDK_NVME_TCP_PDU_TYPE_H2C_TERM_REQ:
  		nvmf_tcp_h2c_term_req_hdr_handle(tqpair, pdu);
  		break;
  
  	default:
  		SPDK_ERRLOG("Unexpected PDU type 0x%02x\n", tqpair->pdu_in_progress.hdr.common.pdu_type);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = 1;
  		nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  		break;
  	}
  }
  
  static void
  nvmf_tcp_pdu_ch_handle(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	struct nvme_tcp_pdu *pdu;
  	uint32_t error_offset = 0;
  	enum spdk_nvme_tcp_term_req_fes fes;
  	uint8_t expected_hlen, pdo;
  	bool plen_error = false, pdo_error = false;
  
  	assert(tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_CH);
  	pdu = &tqpair->pdu_in_progress;
  
  	if (pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_IC_REQ) {
  		if (tqpair->state != NVME_TCP_QPAIR_STATE_INVALID) {
  			SPDK_ERRLOG("Already received ICreq PDU, and reject this pdu=%p\n", pdu);
  			fes = SPDK_NVME_TCP_TERM_REQ_FES_PDU_SEQUENCE_ERROR;
  			goto err;
  		}
  		expected_hlen = sizeof(struct spdk_nvme_tcp_ic_req);
  		if (pdu->hdr.common.plen != expected_hlen) {
  			plen_error = true;
  		}
  	} else {
  		if (tqpair->state != NVME_TCP_QPAIR_STATE_RUNNING) {
  			SPDK_ERRLOG("The TCP/IP connection is not negotitated\n");
  			fes = SPDK_NVME_TCP_TERM_REQ_FES_PDU_SEQUENCE_ERROR;
  			goto err;
  		}
  
  		switch (pdu->hdr.common.pdu_type) {
  		case SPDK_NVME_TCP_PDU_TYPE_CAPSULE_CMD:
  			expected_hlen = sizeof(struct spdk_nvme_tcp_cmd);
  			pdo = pdu->hdr.common.pdo;
  			if ((tqpair->cpda != 0) && (pdo % ((tqpair->cpda + 1) << 2) != 0)) {
  				pdo_error = true;
  				break;
  			}
  
  			if (pdu->hdr.common.plen < expected_hlen) {
  				plen_error = true;
  			}
  			break;
  		case SPDK_NVME_TCP_PDU_TYPE_H2C_DATA:
  			expected_hlen = sizeof(struct spdk_nvme_tcp_h2c_data_hdr);
  			pdo = pdu->hdr.common.pdo;
  			if ((tqpair->cpda != 0) && (pdo % ((tqpair->cpda + 1) << 2) != 0)) {
  				pdo_error = true;
  				break;
  			}
  			if (pdu->hdr.common.plen < expected_hlen) {
  				plen_error = true;
  			}
  			break;
  
  		case SPDK_NVME_TCP_PDU_TYPE_H2C_TERM_REQ:
  			expected_hlen = sizeof(struct spdk_nvme_tcp_term_req_hdr);
  			if ((pdu->hdr.common.plen <= expected_hlen) ||
  			    (pdu->hdr.common.plen > SPDK_NVME_TCP_TERM_REQ_PDU_MAX_SIZE)) {
  				plen_error = true;
  			}
  			break;
  
  		default:
  			SPDK_ERRLOG("Unexpected PDU type 0x%02x\n", pdu->hdr.common.pdu_type);
  			fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  			error_offset = offsetof(struct spdk_nvme_tcp_common_pdu_hdr, pdu_type);
  			goto err;
  		}
  	}
  
  	if (pdu->hdr.common.hlen != expected_hlen) {
  		SPDK_ERRLOG("PDU type=0x%02x, Expected ICReq header length %u, got %u on tqpair=%p\n",
  			    pdu->hdr.common.pdu_type,
  			    expected_hlen, pdu->hdr.common.hlen, tqpair);
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_common_pdu_hdr, hlen);
  		goto err;
  	} else if (pdo_error) {
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_common_pdu_hdr, pdo);
  	} else if (plen_error) {
  		fes = SPDK_NVME_TCP_TERM_REQ_FES_INVALID_HEADER_FIELD;
  		error_offset = offsetof(struct spdk_nvme_tcp_common_pdu_hdr, plen);
  		goto err;
  	} else {
  		nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PSH);
  		nvme_tcp_pdu_calc_psh_len(&tqpair->pdu_in_progress, tqpair->host_hdgst_enable);
  		return;
  	}
  err:
  	nvmf_tcp_send_c2h_term_req(tqpair, pdu, fes, error_offset);
  }
  
  static int
  nvmf_tcp_pdu_payload_insert_dif(struct nvme_tcp_pdu *pdu, uint32_t read_offset,
  				int read_len)
  {
  	int rc;
  
  	rc = spdk_dif_generate_stream(pdu->data_iov, pdu->data_iovcnt,
  				      read_offset, read_len, pdu->dif_ctx);
  	if (rc != 0) {
  		SPDK_ERRLOG("DIF generate failed\n");
  	}
  
  	return rc;
  }
  
  static int
  nvmf_tcp_sock_process(struct spdk_nvmf_tcp_qpair *tqpair)
  {
  	int rc = 0;
  	struct nvme_tcp_pdu *pdu;
  	enum nvme_tcp_pdu_recv_state prev_state;
  	uint32_t data_len;
  	struct spdk_nvmf_tcp_transport *ttransport = SPDK_CONTAINEROF(tqpair->qpair.transport,
  			struct spdk_nvmf_tcp_transport, transport);
  
  	/* The loop here is to allow for several back-to-back state changes. */
  	do {
  		prev_state = tqpair->recv_state;
  		SPDK_DEBUGLOG(nvmf_tcp, "tqpair(%p) recv pdu entering state %d\n", tqpair, prev_state);
  
  		pdu = &tqpair->pdu_in_progress;
  		switch (tqpair->recv_state) {
  		/* Wait for the common header  */
  		case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY:
  		case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_CH:
  			if (spdk_unlikely(tqpair->state == NVME_TCP_QPAIR_STATE_INITIALIZING)) {
  				return rc;
  			}
  
  			rc = nvme_tcp_read_data(tqpair->sock,
  						sizeof(struct spdk_nvme_tcp_common_pdu_hdr) - pdu->ch_valid_bytes,
  						(void *)&pdu->hdr.common + pdu->ch_valid_bytes);
  			if (rc < 0) {
  				SPDK_DEBUGLOG(nvmf_tcp, "will disconnect tqpair=%p\n", tqpair);
  				return NVME_TCP_PDU_FATAL;
  			} else if (rc > 0) {
  				pdu->ch_valid_bytes += rc;
  				spdk_trace_record(TRACE_TCP_READ_FROM_SOCKET_DONE, 0, rc, 0, 0);
  				if (spdk_likely(tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY)) {
  					nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_CH);
  				}
  			}
  
  			if (pdu->ch_valid_bytes < sizeof(struct spdk_nvme_tcp_common_pdu_hdr)) {
  				return NVME_TCP_PDU_IN_PROGRESS;
  			}
  
  			/* The command header of this PDU has now been read from the socket. */
  			nvmf_tcp_pdu_ch_handle(tqpair);
  			break;
  		/* Wait for the pdu specific header  */
  		case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PSH:
  			rc = nvme_tcp_read_data(tqpair->sock,
  						pdu->psh_len - pdu->psh_valid_bytes,
  						(void *)&pdu->hdr.raw + sizeof(struct spdk_nvme_tcp_common_pdu_hdr) + pdu->psh_valid_bytes);
  			if (rc < 0) {
  				return NVME_TCP_PDU_FATAL;
  			} else if (rc > 0) {
  				spdk_trace_record(TRACE_TCP_READ_FROM_SOCKET_DONE,
  						  0, rc, 0, 0);
  				pdu->psh_valid_bytes += rc;
  			}
  
  			if (pdu->psh_valid_bytes < pdu->psh_len) {
  				return NVME_TCP_PDU_IN_PROGRESS;
  			}
  
  			/* All header(ch, psh, head digist) of this PDU has now been read from the socket. */
  			nvmf_tcp_pdu_psh_handle(tqpair, ttransport);
  			break;
  		/* Wait for the req slot */
  		case NVME_TCP_PDU_RECV_STATE_AWAIT_REQ:
  			nvmf_tcp_capsule_cmd_hdr_handle(ttransport, tqpair, pdu);
  			break;
  		case NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD:
  			/* check whether the data is valid, if not we just return */
  			if (!pdu->data_len) {
  				return NVME_TCP_PDU_IN_PROGRESS;
  			}
  
  			data_len = pdu->data_len;
  			/* data digest */
  			if (spdk_unlikely((pdu->hdr.common.pdu_type != SPDK_NVME_TCP_PDU_TYPE_H2C_TERM_REQ) &&
  					  tqpair->host_ddgst_enable)) {
  				data_len += SPDK_NVME_TCP_DIGEST_LEN;
  				pdu->ddgst_enable = true;
  			}
  
  			rc = nvme_tcp_read_payload_data(tqpair->sock, pdu);
  			if (rc < 0) {
  				return NVME_TCP_PDU_FATAL;
  			}
  			pdu->rw_offset += rc;
  
  			if (spdk_unlikely(pdu->dif_ctx != NULL)) {
  				rc = nvmf_tcp_pdu_payload_insert_dif(pdu, pdu->rw_offset - rc, rc);
  				if (rc != 0) {
  					return NVME_TCP_PDU_FATAL;
  				}
  			}
  
  			if (pdu->rw_offset < data_len) {
  				return NVME_TCP_PDU_IN_PROGRESS;
  			}
  
  			/* All of this PDU has now been read from the socket. */
  			nvmf_tcp_pdu_payload_handle(tqpair, ttransport);
  			break;
  		case NVME_TCP_PDU_RECV_STATE_ERROR:
  			if (!spdk_sock_is_connected(tqpair->sock)) {
  				return NVME_TCP_PDU_FATAL;
  			}
  			break;
  		default:
  			assert(0);
  			SPDK_ERRLOG("code should not come to here");
  			break;
  		}
  	} while (tqpair->recv_state != prev_state);
  
  	return rc;
  }
  
  static inline void *
  nvmf_tcp_control_msg_get(struct spdk_nvmf_tcp_control_msg_list *list)
  {
  	struct spdk_nvmf_tcp_control_msg *msg;
  
  	assert(list);
  
  	msg = STAILQ_FIRST(&list->free_msgs);
  	if (!msg) {
  		SPDK_DEBUGLOG(nvmf_tcp, "Out of control messages\n");
  		return NULL;
  	}
  	STAILQ_REMOVE_HEAD(&list->free_msgs, link);
  	return msg;
  }
  
  static inline void
  nvmf_tcp_control_msg_put(struct spdk_nvmf_tcp_control_msg_list *list, void *_msg)
  {
  	struct spdk_nvmf_tcp_control_msg *msg = _msg;
  
  	assert(list);
  	STAILQ_INSERT_HEAD(&list->free_msgs, msg, link);
  }
  
  static int
  nvmf_tcp_req_parse_sgl(struct spdk_nvmf_tcp_req *tcp_req,
  		       struct spdk_nvmf_transport *transport,
  		       struct spdk_nvmf_transport_poll_group *group)
  {
  	struct spdk_nvmf_request		*req = &tcp_req->req;
  	struct spdk_nvme_cmd			*cmd;
  	struct spdk_nvme_cpl			*rsp;
  	struct spdk_nvme_sgl_descriptor		*sgl;
  	struct spdk_nvmf_tcp_poll_group		*tgroup;
  	uint32_t				length;
  
  	cmd = &req->cmd->nvme_cmd;
  	rsp = &req->rsp->nvme_cpl;
  	sgl = &cmd->dptr.sgl1;
  
  	length = sgl->unkeyed.length;
  
  	if (sgl->generic.type == SPDK_NVME_SGL_TYPE_TRANSPORT_DATA_BLOCK &&
  	    sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_TRANSPORT) {
  		if (length > transport->opts.max_io_size) {
  			SPDK_ERRLOG("SGL length 0x%x exceeds max io size 0x%x\n",
  				    length, transport->opts.max_io_size);
  			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
  			return -1;
  		}
  
  		/* fill request length and populate iovs */
  		req->length = length;
  
  		SPDK_DEBUGLOG(nvmf_tcp, "Data requested length= 0x%x\n", length);
  
  		if (spdk_unlikely(req->dif.dif_insert_or_strip)) {
  			req->dif.orig_length = length;
  			length = spdk_dif_get_length_with_md(length, &req->dif.dif_ctx);
  			req->dif.elba_length = length;
  		}
  
  		if (spdk_nvmf_request_get_buffers(req, group, transport, length)) {
  			/* No available buffers. Queue this request up. */
  			SPDK_DEBUGLOG(nvmf_tcp, "No available large data buffers. Queueing request %p\n",
  				      tcp_req);
  			return 0;
  		}
  
  		/* backward compatible */
  		req->data = req->iov[0].iov_base;
  
  		SPDK_DEBUGLOG(nvmf_tcp, "Request %p took %d buffer/s from central pool, and data=%p\n",
  			      tcp_req, req->iovcnt, req->data);
  
  		return 0;
  	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_DATA_BLOCK &&
  		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
  		uint64_t offset = sgl->address;
  		uint32_t max_len = transport->opts.in_capsule_data_size;
  		assert(tcp_req->has_incapsule_data);
  
  		SPDK_DEBUGLOG(nvmf_tcp, "In-capsule data: offset 0x%" PRIx64 ", length 0x%x\n",
  			      offset, length);
  
  		if (offset > max_len) {
  			SPDK_ERRLOG("In-capsule offset 0x%" PRIx64 " exceeds capsule length 0x%x\n",
  				    offset, max_len);
  			rsp->status.sc = SPDK_NVME_SC_INVALID_SGL_OFFSET;
  			return -1;
  		}
  		max_len -= (uint32_t)offset;
  
  		if (spdk_unlikely(length > max_len)) {
  			/* According to the SPEC we should support ICD up to 8192 bytes for admin and fabric commands */
  			if (length <= SPDK_NVME_TCP_IN_CAPSULE_DATA_MAX_SIZE &&
  			    (cmd->opc == SPDK_NVME_OPC_FABRIC || req->qpair->qid == 0)) {
  
  				/* Get a buffer from dedicated list */
  				SPDK_DEBUGLOG(nvmf_tcp, "Getting a buffer from control msg list\n");
  				tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  				assert(tgroup->control_msg_list);
  				req->data = nvmf_tcp_control_msg_get(tgroup->control_msg_list);
  				if (!req->data) {
  					/* No available buffers. Queue this request up. */
  					SPDK_DEBUGLOG(nvmf_tcp, "No available ICD buffers. Queueing request %p\n", tcp_req);
  					return 0;
  				}
  			} else {
  				SPDK_ERRLOG("In-capsule data length 0x%x exceeds capsule length 0x%x\n",
  					    length, max_len);
  				rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
  				return -1;
  			}
  		} else {
  			req->data = tcp_req->buf;
  		}
  
  		req->length = length;
  		req->data_from_pool = false;
  
  		if (spdk_unlikely(req->dif.dif_insert_or_strip)) {
  			length = spdk_dif_get_length_with_md(length, &req->dif.dif_ctx);
  			req->dif.elba_length = length;
  		}
  
  		req->iov[0].iov_base = req->data;
  		req->iov[0].iov_len = length;
  		req->iovcnt = 1;
  
  		return 0;
  	}
  
  	SPDK_ERRLOG("Invalid NVMf I/O Command SGL:  Type 0x%x, Subtype 0x%x\n",
  		    sgl->generic.type, sgl->generic.subtype);
  	rsp->status.sc = SPDK_NVME_SC_SGL_DESCRIPTOR_TYPE_INVALID;
  	return -1;
  }
  
  static inline enum spdk_nvme_media_error_status_code
  nvmf_tcp_dif_error_to_compl_status(uint8_t err_type) {
  	enum spdk_nvme_media_error_status_code result;
  
  	switch (err_type)
  	{
  	case SPDK_DIF_REFTAG_ERROR:
  		result = SPDK_NVME_SC_REFERENCE_TAG_CHECK_ERROR;
  		break;
  	case SPDK_DIF_APPTAG_ERROR:
  		result = SPDK_NVME_SC_APPLICATION_TAG_CHECK_ERROR;
  		break;
  	case SPDK_DIF_GUARD_ERROR:
  		result = SPDK_NVME_SC_GUARD_CHECK_ERROR;
  		break;
  	default:
  		SPDK_UNREACHABLE();
  		break;
  	}
  
  	return result;
  }
  
  static void
  _nvmf_tcp_send_c2h_data(struct spdk_nvmf_tcp_qpair *tqpair,
  			struct spdk_nvmf_tcp_req *tcp_req)
  {
  	struct spdk_nvmf_tcp_transport *ttransport = SPDK_CONTAINEROF(
  				tqpair->qpair.transport, struct spdk_nvmf_tcp_transport, transport);
  	struct nvme_tcp_pdu *rsp_pdu;
  	struct spdk_nvme_tcp_c2h_data_hdr *c2h_data;
  	uint32_t plen, pdo, alignment;
  	int rc;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter\n");
  
  	rsp_pdu = tcp_req->pdu;
  	assert(rsp_pdu != NULL);
  	assert(tcp_req->pdu_in_use);
  
  	c2h_data = &rsp_pdu->hdr.c2h_data;
  	c2h_data->common.pdu_type = SPDK_NVME_TCP_PDU_TYPE_C2H_DATA;
  	plen = c2h_data->common.hlen = sizeof(*c2h_data);
  
  	if (tqpair->host_hdgst_enable) {
  		plen += SPDK_NVME_TCP_DIGEST_LEN;
  		c2h_data->common.flags |= SPDK_NVME_TCP_CH_FLAGS_HDGSTF;
  	}
  
  	/* set the psh */
  	c2h_data->cccid = tcp_req->req.cmd->nvme_cmd.cid;
  	c2h_data->datal = tcp_req->req.length - tcp_req->pdu->rw_offset;
  	c2h_data->datao = tcp_req->pdu->rw_offset;
  
  	/* set the padding */
  	rsp_pdu->padding_len = 0;
  	pdo = plen;
  	if (tqpair->cpda) {
  		alignment = (tqpair->cpda + 1) << 2;
  		if (plen % alignment != 0) {
  			pdo = (plen + alignment) / alignment * alignment;
  			rsp_pdu->padding_len = pdo - plen;
  			plen = pdo;
  		}
  	}
  
  	c2h_data->common.pdo = pdo;
  	plen += c2h_data->datal;
  	if (tqpair->host_ddgst_enable) {
  		c2h_data->common.flags |= SPDK_NVME_TCP_CH_FLAGS_DDGSTF;
  		plen += SPDK_NVME_TCP_DIGEST_LEN;
  	}
  
  	c2h_data->common.plen = plen;
  
  	if (spdk_unlikely(tcp_req->req.dif.dif_insert_or_strip)) {
  		rsp_pdu->dif_ctx = &tcp_req->req.dif.dif_ctx;
  	}
  
  	nvme_tcp_pdu_set_data_buf(rsp_pdu, tcp_req->req.iov, tcp_req->req.iovcnt,
  				  c2h_data->datao, c2h_data->datal);
  
  
  	c2h_data->common.flags |= SPDK_NVME_TCP_C2H_DATA_FLAGS_LAST_PDU;
  	if (ttransport->tcp_opts.c2h_success) {
  		c2h_data->common.flags |= SPDK_NVME_TCP_C2H_DATA_FLAGS_SUCCESS;
  	}
  
  	if (spdk_unlikely(tcp_req->req.dif.dif_insert_or_strip)) {
  		struct spdk_nvme_cpl *rsp = &tcp_req->req.rsp->nvme_cpl;
  		struct spdk_dif_error err_blk = {};
  		uint32_t mapped_length = 0;
  		uint32_t available_iovs = SPDK_COUNTOF(rsp_pdu->iov);
  		uint32_t ddgst_len = 0;
  
  		if (tqpair->host_ddgst_enable) {
  			/* Data digest consumes additional iov entry */
  			available_iovs--;
  			/* plen needs to be updated since nvme_tcp_build_iovs compares expected and actual plen */
  			ddgst_len = SPDK_NVME_TCP_DIGEST_LEN;
  			c2h_data->common.plen -= ddgst_len;
  		}
  		/* Temp call to estimate if data can be described by limited number of iovs.
  		 * iov vector will be rebuilt in nvmf_tcp_qpair_write_pdu */
  		nvme_tcp_build_iovs(rsp_pdu->iov, available_iovs, rsp_pdu, tqpair->host_hdgst_enable,
  				    false, &mapped_length);
  
  		if (mapped_length != c2h_data->common.plen) {
  			c2h_data->datal = mapped_length - (c2h_data->common.plen - c2h_data->datal);
  			SPDK_DEBUGLOG(nvmf_tcp,
  				      "Part C2H, data_len %u (of %u), PDU len %u, updated PDU len %u, offset %u\n",
  				      c2h_data->datal, tcp_req->req.length, c2h_data->common.plen, mapped_length, rsp_pdu->rw_offset);
  			c2h_data->common.plen = mapped_length;
  
  			/* Rebuild pdu->data_iov since data length is changed */
  			nvme_tcp_pdu_set_data_buf(rsp_pdu, tcp_req->req.iov, tcp_req->req.iovcnt, c2h_data->datao,
  						  c2h_data->datal);
  
  			c2h_data->common.flags &= ~(SPDK_NVME_TCP_C2H_DATA_FLAGS_LAST_PDU |
  						    SPDK_NVME_TCP_C2H_DATA_FLAGS_SUCCESS);
  		}
  
  		c2h_data->common.plen += ddgst_len;
  
  		assert(rsp_pdu->rw_offset <= tcp_req->req.length);
  
  		rc = spdk_dif_verify_stream(rsp_pdu->data_iov, rsp_pdu->data_iovcnt,
  					    0, rsp_pdu->data_len, rsp_pdu->dif_ctx, &err_blk);
  		if (rc != 0) {
  			SPDK_ERRLOG("DIF error detected. type=%d, offset=%" PRIu32 "\n",
  				    err_blk.err_type, err_blk.err_offset);
  			rsp->status.sct = SPDK_NVME_SCT_MEDIA_ERROR;
  			rsp->status.sc = nvmf_tcp_dif_error_to_compl_status(err_blk.err_type);
  			nvmf_tcp_req_pdu_fini(tcp_req);
  			nvmf_tcp_send_capsule_resp_pdu(tcp_req, tqpair);
  			return;
  		}
  	}
  
  	rsp_pdu->rw_offset += c2h_data->datal;
  	nvmf_tcp_qpair_write_pdu(tqpair, rsp_pdu, nvmf_tcp_pdu_c2h_data_complete, tcp_req);
  }
  
  static void
  nvmf_tcp_send_c2h_data(struct spdk_nvmf_tcp_qpair *tqpair,
  		       struct spdk_nvmf_tcp_req *tcp_req)
  {
  	nvmf_tcp_req_pdu_init(tcp_req);
  	_nvmf_tcp_send_c2h_data(tqpair, tcp_req);
  }
  
  static int
  request_transfer_out(struct spdk_nvmf_request *req)
  {
  	struct spdk_nvmf_tcp_req	*tcp_req;
  	struct spdk_nvmf_qpair		*qpair;
  	struct spdk_nvmf_tcp_qpair	*tqpair;
  	struct spdk_nvme_cpl		*rsp;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "enter\n");
  
  	qpair = req->qpair;
  	rsp = &req->rsp->nvme_cpl;
  	tcp_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_tcp_req, req);
  
  	/* Advance our sq_head pointer */
  	if (qpair->sq_head == qpair->sq_head_max) {
  		qpair->sq_head = 0;
  	} else {
  		qpair->sq_head++;
  	}
  	rsp->sqhd = qpair->sq_head;
  
  	tqpair = SPDK_CONTAINEROF(tcp_req->req.qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST);
  	if (rsp->status.sc == SPDK_NVME_SC_SUCCESS && req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
  		nvmf_tcp_send_c2h_data(tqpair, tcp_req);
  	} else {
  		nvmf_tcp_send_capsule_resp_pdu(tcp_req, tqpair);
  	}
  
  	return 0;
  }
  
  static void
  nvmf_tcp_set_incapsule_data(struct spdk_nvmf_tcp_qpair *tqpair,
  			    struct spdk_nvmf_tcp_req *tcp_req)
  {
  	struct nvme_tcp_pdu *pdu;
  	uint32_t plen = 0;
  
  	pdu = &tqpair->pdu_in_progress;
  	plen = pdu->hdr.common.hlen;
  
  	if (tqpair->host_hdgst_enable) {
  		plen += SPDK_NVME_TCP_DIGEST_LEN;
  	}
  
  	if (pdu->hdr.common.plen != plen) {
  		tcp_req->has_incapsule_data = true;
  	}
  }
  
  static bool
  nvmf_tcp_req_process(struct spdk_nvmf_tcp_transport *ttransport,
  		     struct spdk_nvmf_tcp_req *tcp_req)
  {
  	struct spdk_nvmf_tcp_qpair		*tqpair;
  	int					rc;
  	enum spdk_nvmf_tcp_req_state		prev_state;
  	bool					progress = false;
  	struct spdk_nvmf_transport		*transport = &ttransport->transport;
  	struct spdk_nvmf_transport_poll_group	*group;
  	struct spdk_nvmf_tcp_poll_group		*tgroup;
  
  	tqpair = SPDK_CONTAINEROF(tcp_req->req.qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	group = &tqpair->group->group;
  	assert(tcp_req->state != TCP_REQUEST_STATE_FREE);
  
  	/* If the qpair is not active, we need to abort the outstanding requests. */
  	if (tqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
  		if (tcp_req->state == TCP_REQUEST_STATE_NEED_BUFFER) {
  			STAILQ_REMOVE(&group->pending_buf_queue, &tcp_req->req, spdk_nvmf_request, buf_link);
  		}
  		nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_COMPLETED);
  	}
  
  	/* The loop here is to allow for several back-to-back state changes. */
  	do {
  		prev_state = tcp_req->state;
  
  		SPDK_DEBUGLOG(nvmf_tcp, "Request %p entering state %d on tqpair=%p\n", tcp_req, prev_state,
  			      tqpair);
  
  		switch (tcp_req->state) {
  		case TCP_REQUEST_STATE_FREE:
  			/* Some external code must kick a request into TCP_REQUEST_STATE_NEW
  			 * to escape this state. */
  			break;
  		case TCP_REQUEST_STATE_NEW:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_NEW, 0, 0, (uintptr_t)tcp_req, 0);
  
  			/* copy the cmd from the receive pdu */
  			tcp_req->cmd = tqpair->pdu_in_progress.hdr.capsule_cmd.ccsqe;
  
  			if (spdk_unlikely(spdk_nvmf_request_get_dif_ctx(&tcp_req->req, &tcp_req->req.dif.dif_ctx))) {
  				tcp_req->req.dif.dif_insert_or_strip = true;
  				tqpair->pdu_in_progress.dif_ctx = &tcp_req->req.dif.dif_ctx;
  			}
  
  			/* The next state transition depends on the data transfer needs of this request. */
  			tcp_req->req.xfer = spdk_nvmf_req_get_xfer(&tcp_req->req);
  
  			if (spdk_unlikely(tcp_req->req.xfer == SPDK_NVME_DATA_BIDIRECTIONAL)) {
  				tcp_req->req.rsp->nvme_cpl.status.sct = SPDK_NVME_SCT_GENERIC;
  				tcp_req->req.rsp->nvme_cpl.status.sct = SPDK_NVME_SC_INVALID_OPCODE;
  				nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_COMPLETE);
  				SPDK_DEBUGLOG(nvmf_tcp, "Request %p: invalid xfer type (BIDIRECTIONAL)\n", tcp_req);
  				break;
  			}
  
  			/* If no data to transfer, ready to execute. */
  			if (tcp_req->req.xfer == SPDK_NVME_DATA_NONE) {
  				/* Reset the tqpair receving pdu state */
  				nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY);
  				nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_EXECUTE);
  				break;
  			}
  
  			nvmf_tcp_set_incapsule_data(tqpair, tcp_req);
  
  			if (!tcp_req->has_incapsule_data) {
  				nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY);
  			}
  
  			nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_NEED_BUFFER);
  			STAILQ_INSERT_TAIL(&group->pending_buf_queue, &tcp_req->req, buf_link);
  			break;
  		case TCP_REQUEST_STATE_NEED_BUFFER:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_NEED_BUFFER, 0, 0, (uintptr_t)tcp_req, 0);
  
  			assert(tcp_req->req.xfer != SPDK_NVME_DATA_NONE);
  
  			if (!tcp_req->has_incapsule_data && (&tcp_req->req != STAILQ_FIRST(&group->pending_buf_queue))) {
  				SPDK_DEBUGLOG(nvmf_tcp,
  					      "Not the first element to wait for the buf for tcp_req(%p) on tqpair=%p\n",
  					      tcp_req, tqpair);
  				/* This request needs to wait in line to obtain a buffer */
  				break;
  			}
  
  			/* Try to get a data buffer */
  			rc = nvmf_tcp_req_parse_sgl(tcp_req, transport, group);
  			if (rc < 0) {
  				STAILQ_REMOVE_HEAD(&group->pending_buf_queue, buf_link);
  				/* Reset the tqpair receving pdu state */
  				nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_ERROR);
  				nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_COMPLETE);
  				break;
  			}
  
  			if (!tcp_req->req.data) {
  				SPDK_DEBUGLOG(nvmf_tcp, "No buffer allocated for tcp_req(%p) on tqpair(%p\n)",
  					      tcp_req, tqpair);
  				/* No buffers available. */
  				break;
  			}
  
  			STAILQ_REMOVE(&group->pending_buf_queue, &tcp_req->req, spdk_nvmf_request, buf_link);
  
  			/* If data is transferring from host to controller, we need to do a transfer from the host. */
  			if (tcp_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
  				if (tcp_req->req.data_from_pool) {
  					SPDK_DEBUGLOG(nvmf_tcp, "Sending R2T for tcp_req(%p) on tqpair=%p\n", tcp_req, tqpair);
  					nvmf_tcp_send_r2t_pdu(tqpair, tcp_req);
  				} else {
  					struct nvme_tcp_pdu *pdu;
  
  					nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER);
  
  					pdu = &tqpair->pdu_in_progress;
  					SPDK_DEBUGLOG(nvmf_tcp, "Not need to send r2t for tcp_req(%p) on tqpair=%p\n", tcp_req,
  						      tqpair);
  					/* No need to send r2t, contained in the capsuled data */
  					nvme_tcp_pdu_set_data_buf(pdu, tcp_req->req.iov, tcp_req->req.iovcnt,
  								  0, tcp_req->req.length);
  					nvmf_tcp_qpair_set_recv_state(tqpair, NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD);
  				}
  				break;
  			}
  
  			nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_EXECUTE);
  			break;
  		case TCP_REQUEST_STATE_AWAITING_R2T_ACK:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_AWAIT_R2T_ACK, 0, 0, (uintptr_t)tcp_req, 0);
  			/* The R2T completion or the h2c data incoming will kick it out of this state. */
  			break;
  		case TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
  
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER, 0, 0,
  					  (uintptr_t)tcp_req, 0);
  			/* Some external code must kick a request into TCP_REQUEST_STATE_READY_TO_EXECUTE
  			 * to escape this state. */
  			break;
  		case TCP_REQUEST_STATE_READY_TO_EXECUTE:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_READY_TO_EXECUTE, 0, 0, (uintptr_t)tcp_req, 0);
  
  			if (spdk_unlikely(tcp_req->req.dif.dif_insert_or_strip)) {
  				assert(tcp_req->req.dif.elba_length >= tcp_req->req.length);
  				tcp_req->req.length = tcp_req->req.dif.elba_length;
  			}
  
  			nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_EXECUTING);
  			spdk_nvmf_request_exec(&tcp_req->req);
  			break;
  		case TCP_REQUEST_STATE_EXECUTING:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_EXECUTING, 0, 0, (uintptr_t)tcp_req, 0);
  			/* Some external code must kick a request into TCP_REQUEST_STATE_EXECUTED
  			 * to escape this state. */
  			break;
  		case TCP_REQUEST_STATE_EXECUTED:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_EXECUTED, 0, 0, (uintptr_t)tcp_req, 0);
  
  			if (spdk_unlikely(tcp_req->req.dif.dif_insert_or_strip)) {
  				tcp_req->req.length = tcp_req->req.dif.orig_length;
  			}
  
  			nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_READY_TO_COMPLETE);
  			break;
  		case TCP_REQUEST_STATE_READY_TO_COMPLETE:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_READY_TO_COMPLETE, 0, 0, (uintptr_t)tcp_req, 0);
  			rc = request_transfer_out(&tcp_req->req);
  			assert(rc == 0); /* No good way to handle this currently */
  			break;
  		case TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST, 0, 0,
  					  (uintptr_t)tcp_req,
  					  0);
  			/* Some external code must kick a request into TCP_REQUEST_STATE_COMPLETED
  			 * to escape this state. */
  			break;
  		case TCP_REQUEST_STATE_COMPLETED:
  			spdk_trace_record(TRACE_TCP_REQUEST_STATE_COMPLETED, 0, 0, (uintptr_t)tcp_req, 0);
  			if (tcp_req->req.data_from_pool) {
  				spdk_nvmf_request_free_buffers(&tcp_req->req, group, transport);
  			} else if (spdk_unlikely(tcp_req->has_incapsule_data && (tcp_req->cmd.opc == SPDK_NVME_OPC_FABRIC ||
  						 tqpair->qpair.qid == 0) && tcp_req->req.length > transport->opts.in_capsule_data_size)) {
  				tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  				assert(tgroup->control_msg_list);
  				SPDK_DEBUGLOG(nvmf_tcp, "Put buf to control msg list\n");
  				nvmf_tcp_control_msg_put(tgroup->control_msg_list, tcp_req->req.data);
  			}
  			tcp_req->req.length = 0;
  			tcp_req->req.iovcnt = 0;
  			tcp_req->req.data = NULL;
  
  			nvmf_tcp_req_pdu_fini(tcp_req);
  
  			nvmf_tcp_req_put(tqpair, tcp_req);
  			break;
  		case TCP_REQUEST_NUM_STATES:
  		default:
  			assert(0);
  			break;
  		}
  
  		if (tcp_req->state != prev_state) {
  			progress = true;
  		}
  	} while (tcp_req->state != prev_state);
  
  	return progress;
  }
  
  static void
  nvmf_tcp_sock_cb(void *arg, struct spdk_sock_group *group, struct spdk_sock *sock)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair = arg;
  	int rc;
  
  	assert(tqpair != NULL);
  	rc = nvmf_tcp_sock_process(tqpair);
  
  	/* If there was a new socket error, disconnect */
  	if (rc < 0) {
  		nvmf_tcp_qpair_disconnect(tqpair);
  	}
  }
  
  static int
  nvmf_tcp_poll_group_add(struct spdk_nvmf_transport_poll_group *group,
  			struct spdk_nvmf_qpair *qpair)
  {
  	struct spdk_nvmf_tcp_poll_group	*tgroup;
  	struct spdk_nvmf_tcp_qpair	*tqpair;
  	int				rc;
  
  	tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  
  	rc = spdk_sock_group_add_sock(tgroup->sock_group, tqpair->sock,
  				      nvmf_tcp_sock_cb, tqpair);
  	if (rc != 0) {
  		SPDK_ERRLOG("Could not add sock to sock_group: %s (%d)\n",
  			    spdk_strerror(errno), errno);
  		return -1;
  	}
  
  	rc =  nvmf_tcp_qpair_sock_init(tqpair);
  	if (rc != 0) {
  		SPDK_ERRLOG("Cannot set sock opt for tqpair=%p\n", tqpair);
  		return -1;
  	}
  
  	rc = nvmf_tcp_qpair_init(&tqpair->qpair);
  	if (rc < 0) {
  		SPDK_ERRLOG("Cannot init tqpair=%p\n", tqpair);
  		return -1;
  	}
  
  	rc = nvmf_tcp_qpair_init_mem_resource(tqpair);
  	if (rc < 0) {
  		SPDK_ERRLOG("Cannot init memory resource info for tqpair=%p\n", tqpair);
  		return -1;
  	}
  
  	tqpair->group = tgroup;
  	tqpair->state = NVME_TCP_QPAIR_STATE_INVALID;
  	TAILQ_INSERT_TAIL(&tgroup->qpairs, tqpair, link);
  
  	return 0;
  }
  
  static int
  nvmf_tcp_poll_group_remove(struct spdk_nvmf_transport_poll_group *group,
  			   struct spdk_nvmf_qpair *qpair)
  {
  	struct spdk_nvmf_tcp_poll_group	*tgroup;
  	struct spdk_nvmf_tcp_qpair		*tqpair;
  	int				rc;
  
  	tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  
  	assert(tqpair->group == tgroup);
  
  	SPDK_DEBUGLOG(nvmf_tcp, "remove tqpair=%p from the tgroup=%p\n", tqpair, tgroup);
  	if (tqpair->recv_state == NVME_TCP_PDU_RECV_STATE_AWAIT_REQ) {
  		TAILQ_REMOVE(&tgroup->await_req, tqpair, link);
  	} else {
  		TAILQ_REMOVE(&tgroup->qpairs, tqpair, link);
  	}
  
  	rc = spdk_sock_group_remove_sock(tgroup->sock_group, tqpair->sock);
  	if (rc != 0) {
  		SPDK_ERRLOG("Could not remove sock from sock_group: %s (%d)\n",
  			    spdk_strerror(errno), errno);
  	}
  
  	return rc;
  }
  
  static int
  nvmf_tcp_req_complete(struct spdk_nvmf_request *req)
  {
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_tcp_req *tcp_req;
  
  	ttransport = SPDK_CONTAINEROF(req->qpair->transport, struct spdk_nvmf_tcp_transport, transport);
  	tcp_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_tcp_req, req);
  
  	nvmf_tcp_req_set_state(tcp_req, TCP_REQUEST_STATE_EXECUTED);
  	nvmf_tcp_req_process(ttransport, tcp_req);
  
  	return 0;
  }
  
  static void
  nvmf_tcp_close_qpair(struct spdk_nvmf_qpair *qpair,
  		     spdk_nvmf_transport_qpair_fini_cb cb_fn, void *cb_arg)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair;
  
  	SPDK_DEBUGLOG(nvmf_tcp, "Qpair: %p\n", qpair);
  
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	tqpair->state = NVME_TCP_QPAIR_STATE_EXITED;
  	nvmf_tcp_qpair_destroy(tqpair);
  
  	if (cb_fn) {
  		cb_fn(cb_arg);
  	}
  }
  
  static int
  nvmf_tcp_poll_group_poll(struct spdk_nvmf_transport_poll_group *group)
  {
  	struct spdk_nvmf_tcp_poll_group *tgroup;
  	int rc;
  	struct spdk_nvmf_request *req, *req_tmp;
  	struct spdk_nvmf_tcp_req *tcp_req;
  	struct spdk_nvmf_tcp_qpair *tqpair, *tqpair_tmp;
  	struct spdk_nvmf_tcp_transport *ttransport = SPDK_CONTAINEROF(group->transport,
  			struct spdk_nvmf_tcp_transport, transport);
  
  	tgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_tcp_poll_group, group);
  
  	if (spdk_unlikely(TAILQ_EMPTY(&tgroup->qpairs) && TAILQ_EMPTY(&tgroup->await_req))) {
  		return 0;
  	}
  
  	STAILQ_FOREACH_SAFE(req, &group->pending_buf_queue, buf_link, req_tmp) {
  		tcp_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_tcp_req, req);
  		if (nvmf_tcp_req_process(ttransport, tcp_req) == false) {
  			break;
  		}
  	}
  
  	rc = spdk_sock_group_poll(tgroup->sock_group);
  	if (rc < 0) {
  		SPDK_ERRLOG("Failed to poll sock_group=%p\n", tgroup->sock_group);
  	}
  
  	TAILQ_FOREACH_SAFE(tqpair, &tgroup->await_req, link, tqpair_tmp) {
  		nvmf_tcp_sock_process(tqpair);
  	}
  
  	return rc;
  }
  
  static int
  nvmf_tcp_qpair_get_trid(struct spdk_nvmf_qpair *qpair,
  			struct spdk_nvme_transport_id *trid, bool peer)
  {
  	struct spdk_nvmf_tcp_qpair     *tqpair;
  	uint16_t			port;
  
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	spdk_nvme_trid_populate_transport(trid, SPDK_NVME_TRANSPORT_TCP);
  
  	if (peer) {
  		snprintf(trid->traddr, sizeof(trid->traddr), "%s", tqpair->initiator_addr);
  		port = tqpair->initiator_port;
  	} else {
  		snprintf(trid->traddr, sizeof(trid->traddr), "%s", tqpair->target_addr);
  		port = tqpair->target_port;
  	}
  
  	if (spdk_sock_is_ipv4(tqpair->sock)) {
  		trid->adrfam = SPDK_NVMF_ADRFAM_IPV4;
  	} else if (spdk_sock_is_ipv6(tqpair->sock)) {
  		trid->adrfam = SPDK_NVMF_ADRFAM_IPV6;
  	} else {
  		return -1;
  	}
  
  	snprintf(trid->trsvcid, sizeof(trid->trsvcid), "%d", port);
  	return 0;
  }
  
  static int
  nvmf_tcp_qpair_get_local_trid(struct spdk_nvmf_qpair *qpair,
  			      struct spdk_nvme_transport_id *trid)
  {
  	return nvmf_tcp_qpair_get_trid(qpair, trid, 0);
  }
  
  static int
  nvmf_tcp_qpair_get_peer_trid(struct spdk_nvmf_qpair *qpair,
  			     struct spdk_nvme_transport_id *trid)
  {
  	return nvmf_tcp_qpair_get_trid(qpair, trid, 1);
  }
  
  static int
  nvmf_tcp_qpair_get_listen_trid(struct spdk_nvmf_qpair *qpair,
  			       struct spdk_nvme_transport_id *trid)
  {
  	return nvmf_tcp_qpair_get_trid(qpair, trid, 0);
  }
  
  static void
  nvmf_tcp_req_set_abort_status(struct spdk_nvmf_request *req,
  			      struct spdk_nvmf_tcp_req *tcp_req_to_abort)
  {
  	tcp_req_to_abort->req.rsp->nvme_cpl.status.sct = SPDK_NVME_SCT_GENERIC;
  	tcp_req_to_abort->req.rsp->nvme_cpl.status.sc = SPDK_NVME_SC_ABORTED_BY_REQUEST;
  
  	nvmf_tcp_req_set_state(tcp_req_to_abort, TCP_REQUEST_STATE_READY_TO_COMPLETE);
  
  	req->rsp->nvme_cpl.cdw0 &= ~1U; /* Command was successfully aborted. */
  }
  
  static int
  _nvmf_tcp_qpair_abort_request(void *ctx)
  {
  	struct spdk_nvmf_request *req = ctx;
  	struct spdk_nvmf_tcp_req *tcp_req_to_abort = SPDK_CONTAINEROF(req->req_to_abort,
  			struct spdk_nvmf_tcp_req, req);
  	struct spdk_nvmf_tcp_qpair *tqpair = SPDK_CONTAINEROF(req->req_to_abort->qpair,
  					     struct spdk_nvmf_tcp_qpair, qpair);
  	int rc;
  
  	spdk_poller_unregister(&req->poller);
  
  	switch (tcp_req_to_abort->state) {
  	case TCP_REQUEST_STATE_EXECUTING:
  		rc = nvmf_ctrlr_abort_request(req);
  		if (rc == SPDK_NVMF_REQUEST_EXEC_STATUS_ASYNCHRONOUS) {
  			return SPDK_POLLER_BUSY;
  		}
  		break;
  
  	case TCP_REQUEST_STATE_NEED_BUFFER:
  		STAILQ_REMOVE(&tqpair->group->group.pending_buf_queue,
  			      &tcp_req_to_abort->req, spdk_nvmf_request, buf_link);
  
  		nvmf_tcp_req_set_abort_status(req, tcp_req_to_abort);
  		break;
  
  	case TCP_REQUEST_STATE_AWAITING_R2T_ACK:
  		nvmf_tcp_req_set_abort_status(req, tcp_req_to_abort);
  		break;
  
  	case TCP_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
  		if (spdk_get_ticks() < req->timeout_tsc) {
  			req->poller = SPDK_POLLER_REGISTER(_nvmf_tcp_qpair_abort_request, req, 0);
  			return SPDK_POLLER_BUSY;
  		}
  		break;
  
  	default:
  		break;
  	}
  
  	spdk_nvmf_request_complete(req);
  	return SPDK_POLLER_BUSY;
  }
  
  static void
  nvmf_tcp_qpair_abort_request(struct spdk_nvmf_qpair *qpair,
  			     struct spdk_nvmf_request *req)
  {
  	struct spdk_nvmf_tcp_qpair *tqpair;
  	struct spdk_nvmf_tcp_transport *ttransport;
  	struct spdk_nvmf_transport *transport;
  	uint16_t cid;
  	uint32_t i;
  	struct spdk_nvmf_tcp_req *tcp_req_to_abort = NULL;
  
  	tqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_tcp_qpair, qpair);
  	ttransport = SPDK_CONTAINEROF(qpair->transport, struct spdk_nvmf_tcp_transport, transport);
  	transport = &ttransport->transport;
  
  	cid = req->cmd->nvme_cmd.cdw10_bits.abort.cid;
  
  	for (i = 0; i < tqpair->resource_count; i++) {
  		if (tqpair->reqs[i].state != TCP_REQUEST_STATE_FREE &&
  		    tqpair->reqs[i].req.cmd->nvme_cmd.cid == cid) {
  			tcp_req_to_abort = &tqpair->reqs[i];
  			break;
  		}
  	}
  
  	if (tcp_req_to_abort == NULL) {
  		spdk_nvmf_request_complete(req);
  		return;
  	}
  
  	req->req_to_abort = &tcp_req_to_abort->req;
  	req->timeout_tsc = spdk_get_ticks() +
  			   transport->opts.abort_timeout_sec * spdk_get_ticks_hz();
  	req->poller = NULL;
  
  	_nvmf_tcp_qpair_abort_request(req);
  }
  
  #define SPDK_NVMF_TCP_DEFAULT_MAX_QUEUE_DEPTH 128
  #define SPDK_NVMF_TCP_DEFAULT_AQ_DEPTH 128
  #define SPDK_NVMF_TCP_DEFAULT_MAX_QPAIRS_PER_CTRLR 128
  #define SPDK_NVMF_TCP_DEFAULT_IN_CAPSULE_DATA_SIZE 4096
  #define SPDK_NVMF_TCP_DEFAULT_MAX_IO_SIZE 131072
  #define SPDK_NVMF_TCP_DEFAULT_IO_UNIT_SIZE 131072
  #define SPDK_NVMF_TCP_DEFAULT_NUM_SHARED_BUFFERS 511
  #define SPDK_NVMF_TCP_DEFAULT_BUFFER_CACHE_SIZE 32
  #define SPDK_NVMF_TCP_DEFAULT_DIF_INSERT_OR_STRIP false
  #define SPDK_NVMF_TCP_DEFAULT_ABORT_TIMEOUT_SEC 1
  
  static void
  nvmf_tcp_opts_init(struct spdk_nvmf_transport_opts *opts)
  {
  	opts->max_queue_depth =		SPDK_NVMF_TCP_DEFAULT_MAX_QUEUE_DEPTH;
  	opts->max_qpairs_per_ctrlr =	SPDK_NVMF_TCP_DEFAULT_MAX_QPAIRS_PER_CTRLR;
  	opts->in_capsule_data_size =	SPDK_NVMF_TCP_DEFAULT_IN_CAPSULE_DATA_SIZE;
  	opts->max_io_size =		SPDK_NVMF_TCP_DEFAULT_MAX_IO_SIZE;
  	opts->io_unit_size =		SPDK_NVMF_TCP_DEFAULT_IO_UNIT_SIZE;
  	opts->max_aq_depth =		SPDK_NVMF_TCP_DEFAULT_AQ_DEPTH;
  	opts->num_shared_buffers =	SPDK_NVMF_TCP_DEFAULT_NUM_SHARED_BUFFERS;
  	opts->buf_cache_size =		SPDK_NVMF_TCP_DEFAULT_BUFFER_CACHE_SIZE;
  	opts->dif_insert_or_strip =	SPDK_NVMF_TCP_DEFAULT_DIF_INSERT_OR_STRIP;
  	opts->abort_timeout_sec =	SPDK_NVMF_TCP_DEFAULT_ABORT_TIMEOUT_SEC;
  	opts->transport_specific =      NULL;
  }
  
  const struct spdk_nvmf_transport_ops spdk_nvmf_transport_tcp = {
  	.name = "TCP",
  	.type = SPDK_NVME_TRANSPORT_TCP,
  	.opts_init = nvmf_tcp_opts_init,
  	.create = nvmf_tcp_create,
  	.dump_opts = nvmf_tcp_dump_opts,
  	.destroy = nvmf_tcp_destroy,
  
  	.listen = nvmf_tcp_listen,
  	.stop_listen = nvmf_tcp_stop_listen,
  	.accept = nvmf_tcp_accept,
  
  	.listener_discover = nvmf_tcp_discover,
  
  	.poll_group_create = nvmf_tcp_poll_group_create,
  	.get_optimal_poll_group = nvmf_tcp_get_optimal_poll_group,
  	.poll_group_destroy = nvmf_tcp_poll_group_destroy,
  	.poll_group_add = nvmf_tcp_poll_group_add,
  	.poll_group_remove = nvmf_tcp_poll_group_remove,
  	.poll_group_poll = nvmf_tcp_poll_group_poll,
  
  	.req_free = nvmf_tcp_req_free,
  	.req_complete = nvmf_tcp_req_complete,
  
  	.qpair_fini = nvmf_tcp_close_qpair,
  	.qpair_get_local_trid = nvmf_tcp_qpair_get_local_trid,
  	.qpair_get_peer_trid = nvmf_tcp_qpair_get_peer_trid,
  	.qpair_get_listen_trid = nvmf_tcp_qpair_get_listen_trid,
  	.qpair_abort_request = nvmf_tcp_qpair_abort_request,
  };
  
  SPDK_NVMF_TRANSPORT_REGISTER(tcp, &spdk_nvmf_transport_tcp);
  SPDK_LOG_REGISTER_COMPONENT(nvmf_tcp)
  