/*
   *  scsi_netlink.c  - SCSI Transport Netlink Interface
   *
   *  Copyright (C) 2006   James Smart, Emulex Corporation
   *
   *  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
   *
   */
  #include <linux/time.h>
  #include <linux/jiffies.h>
  #include <linux/security.h>

  #include <linux/delay.h>

  #include <linux/slab.h>

  #include <linux/export.h>

  #include <net/sock.h>
  #include <net/netlink.h>
  
  #include <scsi/scsi_netlink.h>
  #include "scsi_priv.h"
  
  struct sock *scsi_nl_sock = NULL;
  EXPORT_SYMBOL_GPL(scsi_nl_sock);

  /**

   * scsi_nl_rcv_msg - Receive message handler.
   * @skb:		socket receive buffer
   *
   * Description: Extracts message from a receive buffer.

   *    Validates message header and calls appropriate transport message handler
   *

   *
   **/
  static void
  scsi_nl_rcv_msg(struct sk_buff *skb)
  {
  	struct nlmsghdr *nlh;
  	struct scsi_nl_hdr *hdr;

  	u32 rlen;
  	int err, tport;

  	while (skb->len >= NLMSG_HDRLEN) {

  		err = 0;

  		nlh = nlmsg_hdr(skb);

  		if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
  		    (skb->len < nlh->nlmsg_len)) {
  			printk(KERN_WARNING "%s: discarding partial skb
  ",

  				 __func__);

  			return;
  		}
  
  		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
  		if (rlen > skb->len)
  			rlen = skb->len;
  
  		if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
  			err = -EBADMSG;

  			goto next_msg;

  		}

  		hdr = nlmsg_data(nlh);

  		if ((hdr->version != SCSI_NL_VERSION) ||
  		    (hdr->magic != SCSI_NL_MAGIC)) {
  			err = -EPROTOTYPE;
  			goto next_msg;
  		}

  		if (!netlink_capable(skb, CAP_SYS_ADMIN)) {

  			err = -EPERM;
  			goto next_msg;
  		}
  
  		if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
  			printk(KERN_WARNING "%s: discarding partial message
  ",

  				 __func__);

  			goto next_msg;

  		}
  
  		/*

  		 * Deliver message to the appropriate transport

  		 */

  		tport = hdr->transport;

  		if (tport == SCSI_NL_TRANSPORT) {
  			switch (hdr->msgtype) {
  			case SCSI_NL_SHOST_VENDOR:
  				/* Locate the driver that corresponds to the message */
  				err = -ESRCH;
  				break;
  			default:
  				err = -EBADR;
  				break;
  			}
  			if (err)
  				printk(KERN_WARNING "%s: Msgtype %d failed - err %d
  ",
  				       __func__, hdr->msgtype, err);
  		}
  		else

  			err = -ENOENT;

  next_msg:
  		if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
  			netlink_ack(skb, nlh, err);
  
  		skb_pull(skb, rlen);
  	}
  }

  /**

   * scsi_netlink_init - Called by SCSI subsystem to initialize

   * 	the SCSI transport netlink interface

   *
   **/
  void
  scsi_netlink_init(void)
  {

  	struct netlink_kernel_cfg cfg = {
  		.input	= scsi_nl_rcv_msg,
  		.groups	= SCSI_NL_GRP_CNT,
  	};

  	scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,

  					     &cfg);

  	if (!scsi_nl_sock) {

  		printk(KERN_ERR "%s: register of receive handler failed
  ",

  				__func__);

  		return;

  	}
  
  	return;
  }
  
  
  /**

   * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface

   *
   **/
  void
  scsi_netlink_exit(void)
  {
  	if (scsi_nl_sock) {

  		netlink_kernel_release(scsi_nl_sock);

  	}
  
  	return;
  }