/*******************************************************************************
   * Filename:  target_core_fabric_lib.c
   *
   * This file contains generic high level protocol identifier and PR
   * handlers for TCM fabric modules
   *

   * (c) Copyright 2010-2013 Datera, Inc.

   *
   * Nicholas A. Bellinger <nab@linux-iscsi.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   ******************************************************************************/

  /*
   * See SPC4, section 7.5 "Protocol specific parameters" for details
   * on the formats implemented in this file.
   */

  #include <linux/kernel.h>

  #include <linux/string.h>
  #include <linux/ctype.h>
  #include <linux/spinlock.h>

  #include <linux/export.h>

  #include <asm/unaligned.h>

  #include <scsi/scsi_proto.h>

  #include <target/target_core_base.h>

  #include <target/target_core_fabric.h>

  #include "target_core_internal.h"

  #include "target_core_pr.h"

  static int sas_get_pr_transport_id(
  	struct se_node_acl *nacl,

  	int *format_code,
  	unsigned char *buf)
  {

  	int ret;

  	/* Skip over 'naa. prefix */
  	ret = hex2bin(&buf[4], &nacl->initiatorname[4], 8);
  	if (ret) {
  		pr_debug("%s: invalid hex string
  ", __func__);
  		return ret;
  	}

  	return 24;
  }

  static int fc_get_pr_transport_id(

  	struct se_node_acl *se_nacl,

  	int *format_code,
  	unsigned char *buf)
  {

  	unsigned char *ptr;

  	int i, ret;

  	u32 off = 8;

  	/*

  	 * We convert the ASCII formatted N Port name into a binary
  	 * encoded TransportID.
  	 */
  	ptr = &se_nacl->initiatorname[0];

  	for (i = 0; i < 24; ) {

  		if (!strncmp(&ptr[i], ":", 1)) {

  			i++;
  			continue;
  		}

  		ret = hex2bin(&buf[off++], &ptr[i], 1);

  		if (ret < 0) {
  			pr_debug("%s: invalid hex string
  ", __func__);
  			return ret;
  		}

  		i += 2;
  	}
  	/*
  	 * The FC Transport ID is a hardcoded 24-byte length
  	 */
  	return 24;
  }

  static int sbp_get_pr_transport_id(
  	struct se_node_acl *nacl,
  	int *format_code,
  	unsigned char *buf)

  {

  	int ret;

  	ret = hex2bin(&buf[8], nacl->initiatorname, 8);
  	if (ret) {
  		pr_debug("%s: invalid hex string
  ", __func__);
  		return ret;
  	}

  	return 24;

  }

  static int srp_get_pr_transport_id(
  	struct se_node_acl *nacl,
  	int *format_code,
  	unsigned char *buf)

  {

  	const char *p;
  	unsigned len, count, leading_zero_bytes;
  	int rc;
  
  	p = nacl->initiatorname;
  	if (strncasecmp(p, "0x", 2) == 0)
  		p += 2;
  	len = strlen(p);
  	if (len % 2)
  		return -EINVAL;
  
  	count = min(len / 2, 16U);
  	leading_zero_bytes = 16 - count;
  	memset(buf + 8, 0, leading_zero_bytes);
  	rc = hex2bin(buf + 8 + leading_zero_bytes, p, count);
  	if (rc < 0) {
  		pr_debug("hex2bin failed for %s: %d
  ", __func__, rc);
  		return rc;
  	}
  
  	return 24;

  }

  static int iscsi_get_pr_transport_id(

  	struct se_node_acl *se_nacl,
  	struct t10_pr_registration *pr_reg,
  	int *format_code,
  	unsigned char *buf)
  {
  	u32 off = 4, padding = 0;
  	u16 len = 0;
  
  	spin_lock_irq(&se_nacl->nacl_sess_lock);
  	/*

  	 * From spc4r17 Section 7.5.4.6: TransportID for initiator
  	 * ports using SCSI over iSCSI.
  	 *
  	 * The null-terminated, null-padded (see 4.4.2) ISCSI NAME field
  	 * shall contain the iSCSI name of an iSCSI initiator node (see
  	 * RFC 3720). The first ISCSI NAME field byte containing an ASCII
  	 * null character terminates the ISCSI NAME field without regard for
  	 * the specified length of the iSCSI TransportID or the contents of
  	 * the ADDITIONAL LENGTH field.
  	 */
  	len = sprintf(&buf[off], "%s", se_nacl->initiatorname);
  	/*
  	 * Add Extra byte for NULL terminator
  	 */
  	len++;
  	/*
  	 * If there is ISID present with the registration and *format code == 1
  	 * 1, use iSCSI Initiator port TransportID format.
  	 *
  	 * Otherwise use iSCSI Initiator device TransportID format that
  	 * does not contain the ASCII encoded iSCSI Initiator iSID value
  	 * provied by the iSCSi Initiator during the iSCSI login process.
  	 */
  	if ((*format_code == 1) && (pr_reg->isid_present_at_reg)) {
  		/*
  		 * Set FORMAT CODE 01b for iSCSI Initiator port TransportID
  		 * format.
  		 */
  		buf[0] |= 0x40;
  		/*
  		 * From spc4r17 Section 7.5.4.6: TransportID for initiator
  		 * ports using SCSI over iSCSI.  Table 390
  		 *
  		 * The SEPARATOR field shall contain the five ASCII
  		 * characters ",i,0x".
  		 *
  		 * The null-terminated, null-padded ISCSI INITIATOR SESSION ID
  		 * field shall contain the iSCSI initiator session identifier
  		 * (see RFC 3720) in the form of ASCII characters that are the
  		 * hexadecimal digits converted from the binary iSCSI initiator
  		 * session identifier value. The first ISCSI INITIATOR SESSION
  		 * ID field byte containing an ASCII null character
  		 */
  		buf[off+len] = 0x2c; off++; /* ASCII Character: "," */
  		buf[off+len] = 0x69; off++; /* ASCII Character: "i" */
  		buf[off+len] = 0x2c; off++; /* ASCII Character: "," */
  		buf[off+len] = 0x30; off++; /* ASCII Character: "0" */
  		buf[off+len] = 0x78; off++; /* ASCII Character: "x" */
  		len += 5;
  		buf[off+len] = pr_reg->pr_reg_isid[0]; off++;
  		buf[off+len] = pr_reg->pr_reg_isid[1]; off++;
  		buf[off+len] = pr_reg->pr_reg_isid[2]; off++;
  		buf[off+len] = pr_reg->pr_reg_isid[3]; off++;
  		buf[off+len] = pr_reg->pr_reg_isid[4]; off++;
  		buf[off+len] = pr_reg->pr_reg_isid[5]; off++;
  		buf[off+len] = '\0'; off++;
  		len += 7;
  	}
  	spin_unlock_irq(&se_nacl->nacl_sess_lock);
  	/*
  	 * The ADDITIONAL LENGTH field specifies the number of bytes that follow
  	 * in the TransportID. The additional length shall be at least 20 and
  	 * shall be a multiple of four.
  	*/
  	padding = ((-len) & 3);
  	if (padding != 0)
  		len += padding;

  	put_unaligned_be16(len, &buf[2]);

  	/*
  	 * Increment value for total payload + header length for
  	 * full status descriptor
  	 */
  	len += 4;
  
  	return len;
  }

  static int iscsi_get_pr_transport_id_len(

  	struct se_node_acl *se_nacl,
  	struct t10_pr_registration *pr_reg,
  	int *format_code)
  {
  	u32 len = 0, padding = 0;
  
  	spin_lock_irq(&se_nacl->nacl_sess_lock);
  	len = strlen(se_nacl->initiatorname);
  	/*
  	 * Add extra byte for NULL terminator
  	 */
  	len++;
  	/*
  	 * If there is ISID present with the registration, use format code:
  	 * 01b: iSCSI Initiator port TransportID format
  	 *
  	 * If there is not an active iSCSI session, use format code:
  	 * 00b: iSCSI Initiator device TransportID format
  	 */
  	if (pr_reg->isid_present_at_reg) {

  		len += 5; /* For ",i,0x" ASCII separator */

  		len += 7; /* For iSCSI Initiator Session ID + Null terminator */
  		*format_code = 1;
  	} else
  		*format_code = 0;
  	spin_unlock_irq(&se_nacl->nacl_sess_lock);
  	/*
  	 * The ADDITIONAL LENGTH field specifies the number of bytes that follow
  	 * in the TransportID. The additional length shall be at least 20 and
  	 * shall be a multiple of four.
  	 */
  	padding = ((-len) & 3);
  	if (padding != 0)
  		len += padding;
  	/*
  	 * Increment value for total payload + header length for
  	 * full status descriptor
  	 */
  	len += 4;
  
  	return len;
  }

  static char *iscsi_parse_pr_out_transport_id(

  	struct se_portal_group *se_tpg,

  	char *buf,

  	u32 *out_tid_len,
  	char **port_nexus_ptr)
  {
  	char *p;
  	u32 tid_len, padding;
  	int i;
  	u16 add_len;
  	u8 format_code = (buf[0] & 0xc0);
  	/*
  	 * Check for FORMAT CODE 00b or 01b from spc4r17, section 7.5.4.6:
  	 *
  	 *       TransportID for initiator ports using SCSI over iSCSI,
  	 *       from Table 388 -- iSCSI TransportID formats.
  	 *
  	 *    00b     Initiator port is identified using the world wide unique
  	 *            SCSI device name of the iSCSI initiator
  	 *            device containing the initiator port (see table 389).
  	 *    01b     Initiator port is identified using the world wide unique
  	 *            initiator port identifier (see table 390).10b to 11b
  	 *            Reserved
  	 */
  	if ((format_code != 0x00) && (format_code != 0x40)) {

  		pr_err("Illegal format code: 0x%02x for iSCSI"

  			" Initiator Transport ID
  ", format_code);
  		return NULL;
  	}
  	/*
  	 * If the caller wants the TransportID Length, we set that value for the
  	 * entire iSCSI Tarnsport ID now.
  	 */

  	if (out_tid_len) {
  		/* The shift works thanks to integer promotion rules */

  		add_len = get_unaligned_be16(&buf[2]);

  		tid_len = strlen(&buf[4]);

  		tid_len += 4; /* Add four bytes for iSCSI Transport ID header */
  		tid_len += 1; /* Add one byte for NULL terminator */
  		padding = ((-tid_len) & 3);
  		if (padding != 0)
  			tid_len += padding;
  
  		if ((add_len + 4) != tid_len) {

  			pr_debug("LIO-Target Extracted add_len: %hu "

  				"does not match calculated tid_len: %u,"
  				" using tid_len instead
  ", add_len+4, tid_len);
  			*out_tid_len = tid_len;
  		} else
  			*out_tid_len = (add_len + 4);
  	}
  	/*

  	 * Check for ',i,0x' separator between iSCSI Name and iSCSI Initiator

  	 * Session ID as defined in Table 390 - iSCSI initiator port TransportID
  	 * format.
  	 */
  	if (format_code == 0x40) {

  		p = strstr(&buf[4], ",i,0x");

  		if (!p) {

  			pr_err("Unable to locate \",i,0x\" separator"

  				" for Initiator port identifier: %s
  ",

  				&buf[4]);

  			return NULL;
  		}
  		*p = '\0'; /* Terminate iSCSI Name */

  		p += 5; /* Skip over ",i,0x" separator */

  
  		*port_nexus_ptr = p;
  		/*
  		 * Go ahead and do the lower case conversion of the received
  		 * 12 ASCII characters representing the ISID in the TransportID

  		 * for comparison against the running iSCSI session's ISID from

  		 * iscsi_target.c:lio_sess_get_initiator_sid()
  		 */
  		for (i = 0; i < 12; i++) {
  			if (isdigit(*p)) {
  				p++;
  				continue;
  			}
  			*p = tolower(*p);
  			p++;
  		}
  	}

  	return &buf[4];

  }

  
  int target_get_pr_transport_id_len(struct se_node_acl *nacl,
  		struct t10_pr_registration *pr_reg, int *format_code)
  {
  	switch (nacl->se_tpg->proto_id) {
  	case SCSI_PROTOCOL_FCP:
  	case SCSI_PROTOCOL_SBP:
  	case SCSI_PROTOCOL_SRP:
  	case SCSI_PROTOCOL_SAS:
  		break;
  	case SCSI_PROTOCOL_ISCSI:
  		return iscsi_get_pr_transport_id_len(nacl, pr_reg, format_code);
  	default:
  		pr_err("Unknown proto_id: 0x%02x
  ", nacl->se_tpg->proto_id);
  		return -EINVAL;
  	}
  
  	/*
  	 * Most transports use a fixed length 24 byte identifier.
  	 */
  	*format_code = 0;
  	return 24;
  }
  
  int target_get_pr_transport_id(struct se_node_acl *nacl,
  		struct t10_pr_registration *pr_reg, int *format_code,
  		unsigned char *buf)
  {
  	switch (nacl->se_tpg->proto_id) {
  	case SCSI_PROTOCOL_SAS:
  		return sas_get_pr_transport_id(nacl, format_code, buf);
  	case SCSI_PROTOCOL_SBP:
  		return sbp_get_pr_transport_id(nacl, format_code, buf);
  	case SCSI_PROTOCOL_SRP:
  		return srp_get_pr_transport_id(nacl, format_code, buf);
  	case SCSI_PROTOCOL_FCP:
  		return fc_get_pr_transport_id(nacl, format_code, buf);
  	case SCSI_PROTOCOL_ISCSI:
  		return iscsi_get_pr_transport_id(nacl, pr_reg, format_code,
  				buf);
  	default:
  		pr_err("Unknown proto_id: 0x%02x
  ", nacl->se_tpg->proto_id);
  		return -EINVAL;
  	}
  }
  
  const char *target_parse_pr_out_transport_id(struct se_portal_group *tpg,

  		char *buf, u32 *out_tid_len, char **port_nexus_ptr)

  {
  	u32 offset;
  
  	switch (tpg->proto_id) {
  	case SCSI_PROTOCOL_SAS:
  		/*
  		 * Assume the FORMAT CODE 00b from spc4r17, 7.5.4.7 TransportID
  		 * for initiator ports using SCSI over SAS Serial SCSI Protocol.
  		 */
  		offset = 4;
  		break;
  	case SCSI_PROTOCOL_SBP:
  	case SCSI_PROTOCOL_SRP:
  	case SCSI_PROTOCOL_FCP:
  		offset = 8;
  		break;
  	case SCSI_PROTOCOL_ISCSI:
  		return iscsi_parse_pr_out_transport_id(tpg, buf, out_tid_len,
  					port_nexus_ptr);
  	default:
  		pr_err("Unknown proto_id: 0x%02x
  ", tpg->proto_id);
  		return NULL;
  	}
  
  	*port_nexus_ptr = NULL;
  	*out_tid_len = 24;
  	return buf + offset;
  }