/*
   * Ultra Wide Band
   * Address management
   *
   * Copyright (C) 2005-2006 Intel Corporation
   * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation.
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston, MA
   * 02110-1301, USA.
   *
   *
   * FIXME: docs
   */
  
  #include <linux/slab.h>
  #include <linux/errno.h>
  #include <linux/module.h>
  #include <linux/device.h>
  #include <linux/random.h>
  #include <linux/etherdevice.h>
  
  #include "uwb-internal.h"
  
  
  /** Device Address Management command */
  struct uwb_rc_cmd_dev_addr_mgmt {
  	struct uwb_rccb rccb;
  	u8 bmOperationType;
  	u8 baAddr[6];
  } __attribute__((packed));
  
  
  /**
   * Low level command for setting/getting UWB radio's addresses
   *
   * @hwarc:	HWA Radio Control interface instance
   * @bmOperationType:
   * 		Set/get, MAC/DEV (see WUSB1.0[8.6.2.2])
   * @baAddr:	address buffer--assumed to have enough data to hold
   *              the address type requested.
   * @reply:	Pointer to reply buffer (can be stack allocated)
   * @returns:	0 if ok, < 0 errno code on error.
   *
   * @cmd has to be allocated because USB cannot grok USB or vmalloc
   * buffers depending on your combination of host architecture.
   */
  static
  int uwb_rc_dev_addr_mgmt(struct uwb_rc *rc,
  			 u8 bmOperationType, const u8 *baAddr,
  			 struct uwb_rc_evt_dev_addr_mgmt *reply)
  {
  	int result;
  	struct uwb_rc_cmd_dev_addr_mgmt *cmd;
  
  	result = -ENOMEM;
  	cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
  	if (cmd == NULL)
  		goto error_kzalloc;
  	cmd->rccb.bCommandType = UWB_RC_CET_GENERAL;
  	cmd->rccb.wCommand = cpu_to_le16(UWB_RC_CMD_DEV_ADDR_MGMT);
  	cmd->bmOperationType = bmOperationType;
  	if (baAddr) {
  		size_t size = 0;
  		switch (bmOperationType >> 1) {
  		case 0:	size = 2; break;
  		case 1:	size = 6; break;
  		default: BUG();
  		}
  		memcpy(cmd->baAddr, baAddr, size);
  	}
  	reply->rceb.bEventType = UWB_RC_CET_GENERAL;
  	reply->rceb.wEvent = UWB_RC_CMD_DEV_ADDR_MGMT;
  	result = uwb_rc_cmd(rc, "DEV-ADDR-MGMT",
  			    &cmd->rccb, sizeof(*cmd),
  			    &reply->rceb, sizeof(*reply));
  	if (result < 0)
  		goto error_cmd;
  	if (result < sizeof(*reply)) {
  		dev_err(&rc->uwb_dev.dev,
  			"DEV-ADDR-MGMT: not enough data replied: "
  			"%d vs %zu bytes needed
  ", result, sizeof(*reply));
  		result = -ENOMSG;
  	} else if (reply->bResultCode != UWB_RC_RES_SUCCESS) {
  		dev_err(&rc->uwb_dev.dev,
  			"DEV-ADDR-MGMT: command execution failed: %s (%d)
  ",
  			uwb_rc_strerror(reply->bResultCode),
  			reply->bResultCode);
  		result = -EIO;
  	} else
  		result = 0;
  error_cmd:
  	kfree(cmd);
  error_kzalloc:
  	return result;
  }
  
  
  /**
   * Set the UWB RC MAC or device address.
   *
   * @rc:      UWB Radio Controller
   * @_addr:   Pointer to address to write [assumed to be either a
   *           'struct uwb_mac_addr *' or a 'struct uwb_dev_addr *'].
   * @type:    Type of address to set (UWB_ADDR_DEV or UWB_ADDR_MAC).
   * @returns: 0 if ok, < 0 errno code on error.
   *
   * Some anal retentivity here: even if both 'struct
   * uwb_{dev,mac}_addr' have the actual byte array in the same offset
   * and I could just pass _addr to hwarc_cmd_dev_addr_mgmt(), I prefer
   * to use some syntatic sugar in case someday we decide to change the
   * format of the structs. The compiler will optimize it out anyway.
   */
  static int uwb_rc_addr_set(struct uwb_rc *rc,
  		    const void *_addr, enum uwb_addr_type type)
  {
  	int result;
  	u8 bmOperationType = 0x1; 		/* Set address */
  	const struct uwb_dev_addr *dev_addr = _addr;
  	const struct uwb_mac_addr *mac_addr = _addr;
  	struct uwb_rc_evt_dev_addr_mgmt reply;
  	const u8 *baAddr;
  
  	result = -EINVAL;
  	switch (type) {
  	case UWB_ADDR_DEV:
  		baAddr = dev_addr->data;
  		break;
  	case UWB_ADDR_MAC:
  		baAddr = mac_addr->data;
  		bmOperationType |= 0x2;
  		break;
  	default:
  		return result;
  	}
  	return uwb_rc_dev_addr_mgmt(rc, bmOperationType, baAddr, &reply);
  }
  
  
  /**
   * Get the UWB radio's MAC or device address.
   *
   * @rc:      UWB Radio Controller
   * @_addr:   Where to write the address data [assumed to be either a
   *           'struct uwb_mac_addr *' or a 'struct uwb_dev_addr *'].
   * @type:    Type of address to get (UWB_ADDR_DEV or UWB_ADDR_MAC).
   * @returns: 0 if ok (and *_addr set), < 0 errno code on error.
   *
   * See comment in uwb_rc_addr_set() about anal retentivity in the
   * type handling of the address variables.
   */
  static int uwb_rc_addr_get(struct uwb_rc *rc,
  		    void *_addr, enum uwb_addr_type type)
  {
  	int result;
  	u8 bmOperationType = 0x0; 		/* Get address */
  	struct uwb_rc_evt_dev_addr_mgmt evt;
  	struct uwb_dev_addr *dev_addr = _addr;
  	struct uwb_mac_addr *mac_addr = _addr;
  	u8 *baAddr;
  
  	result = -EINVAL;
  	switch (type) {
  	case UWB_ADDR_DEV:
  		baAddr = dev_addr->data;
  		break;
  	case UWB_ADDR_MAC:
  		bmOperationType |= 0x2;
  		baAddr = mac_addr->data;
  		break;
  	default:
  		return result;
  	}
  	result = uwb_rc_dev_addr_mgmt(rc, bmOperationType, baAddr, &evt);
  	if (result == 0)
  		switch (type) {
  		case UWB_ADDR_DEV:
  			memcpy(&dev_addr->data, evt.baAddr,
  			       sizeof(dev_addr->data));
  			break;
  		case UWB_ADDR_MAC:
  			memcpy(&mac_addr->data, evt.baAddr,
  			       sizeof(mac_addr->data));
  			break;
  		default:		/* shut gcc up */
  			BUG();
  		}
  	return result;
  }
  
  
  /** Get @rc's MAC address to @addr */
  int uwb_rc_mac_addr_get(struct uwb_rc *rc,
  			struct uwb_mac_addr *addr) {
  	return uwb_rc_addr_get(rc, addr, UWB_ADDR_MAC);
  }
  EXPORT_SYMBOL_GPL(uwb_rc_mac_addr_get);
  
  
  /** Get @rc's device address to @addr */
  int uwb_rc_dev_addr_get(struct uwb_rc *rc,
  			struct uwb_dev_addr *addr) {
  	return uwb_rc_addr_get(rc, addr, UWB_ADDR_DEV);
  }
  EXPORT_SYMBOL_GPL(uwb_rc_dev_addr_get);
  
  
  /** Set @rc's address to @addr */
  int uwb_rc_mac_addr_set(struct uwb_rc *rc,
  			const struct uwb_mac_addr *addr)
  {
  	int result = -EINVAL;
  	mutex_lock(&rc->uwb_dev.mutex);
  	result = uwb_rc_addr_set(rc, addr, UWB_ADDR_MAC);
  	mutex_unlock(&rc->uwb_dev.mutex);
  	return result;
  }
  
  
  /** Set @rc's address to @addr */
  int uwb_rc_dev_addr_set(struct uwb_rc *rc,
  			const struct uwb_dev_addr *addr)
  {
  	int result = -EINVAL;
  	mutex_lock(&rc->uwb_dev.mutex);
  	result = uwb_rc_addr_set(rc, addr, UWB_ADDR_DEV);
  	rc->uwb_dev.dev_addr = *addr;
  	mutex_unlock(&rc->uwb_dev.mutex);
  	return result;
  }
  
  /* Returns !0 if given address is already assigned to device. */
  int __uwb_mac_addr_assigned_check(struct device *dev, void *_addr)
  {
  	struct uwb_dev *uwb_dev = to_uwb_dev(dev);
  	struct uwb_mac_addr *addr = _addr;
  
  	if (!uwb_mac_addr_cmp(addr, &uwb_dev->mac_addr))
  		return !0;
  	return 0;
  }
  
  /* Returns !0 if given address is already assigned to device. */
  int __uwb_dev_addr_assigned_check(struct device *dev, void *_addr)
  {
  	struct uwb_dev *uwb_dev = to_uwb_dev(dev);
  	struct uwb_dev_addr *addr = _addr;
  	if (!uwb_dev_addr_cmp(addr, &uwb_dev->dev_addr))
  		return !0;
  	return 0;
  }
  
  /**
   * uwb_dev_addr_assign - assigned a generated DevAddr to a radio controller
   * @rc:      the (local) radio controller device requiring a new DevAddr
   *
   * A new DevAddr is required when:
   *    - first setting up a radio controller
   *    - if the hardware reports a DevAddr conflict
   *
   * The DevAddr is randomly generated in the generated DevAddr range
   * [0x100, 0xfeff]. The number of devices in a beacon group is limited
   * by mMaxBPLength (96) so this address space will never be exhausted.
   *
   * [ECMA-368] 17.1.1, 17.16.
   */
  int uwb_rc_dev_addr_assign(struct uwb_rc *rc)
  {
  	struct uwb_dev_addr new_addr;
  
  	do {
  		get_random_bytes(new_addr.data, sizeof(new_addr.data));
  	} while (new_addr.data[0] == 0x00 || new_addr.data[0] == 0xff
  		 || __uwb_dev_addr_assigned(rc, &new_addr));
  
  	return uwb_rc_dev_addr_set(rc, &new_addr);
  }
  
  /**
   * uwbd_evt_handle_rc_dev_addr_conflict - handle a DEV_ADDR_CONFLICT event
   * @evt: the DEV_ADDR_CONFLICT notification from the radio controller
   *
   * A new (non-conflicting) DevAddr is assigned to the radio controller.
   *
   * [ECMA-368] 17.1.1.1.
   */
  int uwbd_evt_handle_rc_dev_addr_conflict(struct uwb_event *evt)
  {
  	struct uwb_rc *rc = evt->rc;
  
  	return uwb_rc_dev_addr_assign(rc);
  }
  
  /*
   * Print the 48-bit EUI MAC address of the radio controller when
   * reading /sys/class/uwb_rc/XX/mac_address
   */
  static ssize_t uwb_rc_mac_addr_show(struct device *dev,
  				    struct device_attribute *attr, char *buf)
  {
  	struct uwb_dev *uwb_dev = to_uwb_dev(dev);
  	struct uwb_rc *rc = uwb_dev->rc;
  	struct uwb_mac_addr addr;
  	ssize_t result;
  
  	mutex_lock(&rc->uwb_dev.mutex);
  	result = uwb_rc_addr_get(rc, &addr, UWB_ADDR_MAC);
  	mutex_unlock(&rc->uwb_dev.mutex);
  	if (result >= 0) {
  		result = uwb_mac_addr_print(buf, UWB_ADDR_STRSIZE, &addr);
  		buf[result++] = '
  ';
  	}
  	return result;
  }
  
  /*
   * Parse a 48 bit address written to /sys/class/uwb_rc/XX/mac_address
   * and if correct, set it.
   */
  static ssize_t uwb_rc_mac_addr_store(struct device *dev,
  				     struct device_attribute *attr,
  				     const char *buf, size_t size)
  {
  	struct uwb_dev *uwb_dev = to_uwb_dev(dev);
  	struct uwb_rc *rc = uwb_dev->rc;
  	struct uwb_mac_addr addr;
  	ssize_t result;
  
  	result = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx
  ",
  			&addr.data[0], &addr.data[1], &addr.data[2],
  			&addr.data[3], &addr.data[4], &addr.data[5]);
  	if (result != 6) {
  		result = -EINVAL;
  		goto out;
  	}
  	if (is_multicast_ether_addr(addr.data)) {
  		dev_err(&rc->uwb_dev.dev, "refusing to set multicast "
  			"MAC address %s
  ", buf);
  		result = -EINVAL;
  		goto out;
  	}
  	result = uwb_rc_mac_addr_set(rc, &addr);
  	if (result == 0)
  		rc->uwb_dev.mac_addr = addr;
  out:
  	return result < 0 ? result : size;
  }
  DEVICE_ATTR(mac_address, S_IRUGO | S_IWUSR, uwb_rc_mac_addr_show, uwb_rc_mac_addr_store);
  
  /** Print @addr to @buf, @return bytes written */
  size_t __uwb_addr_print(char *buf, size_t buf_size, const unsigned char *addr,
  			int type)
  {
  	size_t result;
  	if (type)
  		result = scnprintf(buf, buf_size, "%pM", addr);
  	else
  		result = scnprintf(buf, buf_size, "%02x:%02x",
  				  addr[1], addr[0]);
  	return result;
  }
  EXPORT_SYMBOL_GPL(__uwb_addr_print);