/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
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 *   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.
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 *       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
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 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef SPDK_INTERNAL_NVME_TCP_H
#define SPDK_INTERNAL_NVME_TCP_H

#include "spdk/sock.h"

#define SPDK_CRC32C_XOR				0xffffffffUL
#define SPDK_NVME_TCP_DIGEST_LEN		4
#define SPDK_NVME_TCP_DIGEST_ALIGNMENT		4
#define SPDK_NVME_TCP_QPAIR_EXIT_TIMEOUT	30

#define MAKE_DIGEST_WORD(BUF, CRC32C) \
        (   ((*((uint8_t *)(BUF)+0)) = (uint8_t)((uint32_t)(CRC32C) >> 0)), \
            ((*((uint8_t *)(BUF)+1)) = (uint8_t)((uint32_t)(CRC32C) >> 8)), \
            ((*((uint8_t *)(BUF)+2)) = (uint8_t)((uint32_t)(CRC32C) >> 16)), \
            ((*((uint8_t *)(BUF)+3)) = (uint8_t)((uint32_t)(CRC32C) >> 24)))

#define MATCH_DIGEST_WORD(BUF, CRC32C) \
        (    ((((uint32_t) *((uint8_t *)(BUF)+0)) << 0)         \
            | (((uint32_t) *((uint8_t *)(BUF)+1)) << 8)         \
            | (((uint32_t) *((uint8_t *)(BUF)+2)) << 16)        \
            | (((uint32_t) *((uint8_t *)(BUF)+3)) << 24))       \
            == (CRC32C))

#define DGET32(B)                                                               \
        (((  (uint32_t) *((uint8_t *)(B)+0)) << 0)                              \
         | (((uint32_t) *((uint8_t *)(B)+1)) << 8)                              \
         | (((uint32_t) *((uint8_t *)(B)+2)) << 16)                             \
         | (((uint32_t) *((uint8_t *)(B)+3)) << 24))

#define DSET32(B,D)                                                             \
        (((*((uint8_t *)(B)+0)) = (uint8_t)((uint32_t)(D) >> 0)),               \
         ((*((uint8_t *)(B)+1)) = (uint8_t)((uint32_t)(D) >> 8)),               \
         ((*((uint8_t *)(B)+2)) = (uint8_t)((uint32_t)(D) >> 16)),              \
         ((*((uint8_t *)(B)+3)) = (uint8_t)((uint32_t)(D) >> 24)))

struct nvme_tcp_qpair;
struct nvme_tcp_req;
typedef void (*nvme_tcp_qpair_xfer_complete_cb)(void *cb_arg);

struct nvme_tcp_pdu {
	union {
		/* to hold error pdu data */
		uint8_t                                 raw[SPDK_NVME_TCP_TERM_REQ_PDU_MAX_SIZE];
		struct spdk_nvme_tcp_common_pdu_hdr     common;
		struct spdk_nvme_tcp_ic_req             ic_req;
		struct spdk_nvme_tcp_term_req_hdr       term_req;
		struct spdk_nvme_tcp_cmd                capsule_cmd;
		struct spdk_nvme_tcp_h2c_data_hdr       h2c_data;
		struct spdk_nvme_tcp_ic_resp            ic_resp;
		struct spdk_nvme_tcp_rsp                capsule_resp;
		struct spdk_nvme_tcp_c2h_data_hdr       c2h_data;
		struct spdk_nvme_tcp_r2t_hdr            r2t;

	} hdr;

	bool                                            has_hdgst;
	uint8_t                                         data_digest[SPDK_NVME_TCP_DIGEST_LEN];
	int32_t                                         padding_valid_bytes;
	uint32_t                                        ddigest_valid_bytes;

	uint32_t                                        ch_valid_bytes;
	uint32_t                                        psh_valid_bytes;
	uint32_t                                        data_valid_bytes;

	nvme_tcp_qpair_xfer_complete_cb			cb_fn;
	void                                            *cb_arg;
	int                                             ref;
	void                                            *data;
	uint32_t                                        data_len;
	struct nvme_tcp_qpair				*tqpair;

	struct nvme_tcp_req				*tcp_req; /* data tied to a tcp request */
	uint32_t                                        writev_offset;
	TAILQ_ENTRY(nvme_tcp_pdu)			tailq;
	uint32_t                                        remaining;
	uint32_t                                        padding_len;
};

enum nvme_tcp_pdu_recv_state {
	/* Ready to wait to wait PDU */
	NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_READY,

	/* Active tqpair waiting for any PDU common header */
	NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_CH,

	/* Active tqpair waiting for any PDU specific header */
	NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PSH,

	/* Active tqpair waiting for payload */
	NVME_TCP_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD,

	/* Active tqpair does not wait for payload */
	NVME_TCP_PDU_RECV_STATE_ERROR,
};

enum nvme_tcp_error_codes {
	NVME_TCP_PDU_IN_PROGRESS        = 0,
	NVME_TCP_CONNECTION_FATAL       = -1,
	NVME_TCP_PDU_FATAL              = -2,
};

enum nvme_tcp_qpair_state {
	NVME_TCP_QPAIR_STATE_INVALID = 0,
	NVME_TCP_QPAIR_STATE_RUNNING = 1,
	NVME_TCP_QPAIR_STATE_EXITING = 2,
	NVME_TCP_QPAIR_STATE_EXITED = 3,
};

static uint32_t
nvme_tcp_pdu_calc_header_digest(struct nvme_tcp_pdu *pdu)
{
	uint32_t crc32c;
	uint32_t hlen = pdu->hdr.common.hlen;

	crc32c = spdk_crc32c_update(&pdu->hdr.raw, hlen, ~0);
	crc32c = crc32c ^ SPDK_CRC32C_XOR;
	return crc32c;
}

static uint32_t
nvme_tcp_pdu_calc_data_digest(struct nvme_tcp_pdu *pdu)
{
	uint32_t crc32c;
	uint32_t mod;

	assert(pdu->data != NULL);
	assert(pdu->data_len != 0);

	crc32c = spdk_crc32c_update(pdu->data, pdu->data_len, ~0);

	mod = pdu->data_len % SPDK_NVME_TCP_DIGEST_ALIGNMENT;
	if (mod != 0) {
		uint32_t pad_length = SPDK_NVME_TCP_DIGEST_ALIGNMENT - mod;
		uint8_t pad[3] = {0, 0, 0};

		assert(pad_length > 0);
		assert(pad_length <= sizeof(pad));
		crc32c = spdk_crc32c_update(pad, pad_length, crc32c);
	}

	crc32c = crc32c ^ SPDK_CRC32C_XOR;
	return crc32c;
}

static int
nvme_tcp_build_iovecs(struct iovec *iovec, struct nvme_tcp_pdu *pdu,
		      bool hdgst_enable, bool ddgst_enable)
{

	int iovec_cnt = 0;
	int enable_digest;
	int hlen;
	uint32_t plen;

	hlen = pdu->hdr.common.hlen;
	enable_digest = 1;
	if (pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_IC_REQ ||
	    pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_IC_RESP ||
	    pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_H2C_TERM_REQ ||
	    pdu->hdr.common.pdu_type == SPDK_NVME_TCP_PDU_TYPE_C2H_TERM_REQ) {
		/* this PDU should be sent without digest */
		enable_digest = 0;
	}

	/* Header Digest */
	if (enable_digest && hdgst_enable) {
		hlen += SPDK_NVME_TCP_DIGEST_LEN;
	}

	/* PDU header + possible header digest */
	iovec[iovec_cnt].iov_base = &pdu->hdr.raw;
	iovec[iovec_cnt].iov_len = hlen;
	plen = iovec[iovec_cnt].iov_len;
	iovec_cnt++;

	if (!pdu->data_len || !pdu->data) {
		goto end;
	}

	/* Padding  */
	if (pdu->padding_len > 0) {
		iovec[iovec_cnt - 1].iov_len += pdu->padding_len;
		plen = iovec[iovec_cnt - 1].iov_len;
	}

	/* Data Segment */
	iovec[iovec_cnt].iov_base = pdu->data;
	iovec[iovec_cnt].iov_len = pdu->data_len;
	plen += iovec[iovec_cnt].iov_len;
	iovec_cnt++;

	/* Data Digest */
	if (enable_digest && ddgst_enable) {
		iovec[iovec_cnt].iov_base = pdu->data_digest;
		iovec[iovec_cnt].iov_len = SPDK_NVME_TCP_DIGEST_LEN;
		plen += iovec[iovec_cnt].iov_len;
		iovec_cnt++;
	}

end:
	assert(plen == pdu->hdr.common.plen);
	return iovec_cnt;
}

static int
nvme_tcp_read_data(struct spdk_sock *sock, int bytes,
		   void *buf)
{
	int ret;

	assert(sock != NULL);
	if (bytes == 0) {
		return 0;
	}

	ret = spdk_sock_recv(sock, buf, bytes);

	if (ret > 0) {
		return ret;
	}

	if (ret < 0) {
		if (errno == EAGAIN || errno == EWOULDBLOCK) {
			return 0;
		}

		/* For connect reset issue, do not output error log */
		if (errno == ECONNRESET) {
			SPDK_DEBUGLOG(SPDK_LOG_NVME, "spdk_sock_recv() failed, errno %d: %s\n",
				      errno, spdk_strerror(errno));
		} else {
			SPDK_ERRLOG("spdk_sock_recv() failed, errno %d: %s\n",
				    errno, spdk_strerror(errno));
		}
	}

	return NVME_TCP_CONNECTION_FATAL;
}

#endif /* SPDK_INTERNAL_NVME_TCP_H */