drivers/scsi/scsi_netlink.c

   1 /*
   2  *  scsi_netlink.c  - SCSI Transport Netlink Interface
   3  *
   4  *  Copyright (C) 2006   James Smart, Emulex Corporation
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21 #include <linux/time.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/security.h>
  24 #include <net/sock.h>
  25 #include <net/netlink.h>
  26
  27 #include <scsi/scsi_netlink.h>
  28 #include "scsi_priv.h"
  29
  30 struct sock *scsi_nl_sock = NULL;
  31 EXPORT_SYMBOL_GPL(scsi_nl_sock);
  32
  33
  34 /**
  35  * scsi_nl_rcv_msg - Receive message handler.
  36  * @skb:                socket receive buffer
  37  *
  38  * Description: Extracts message from a receive buffer.
  39  *    Validates message header and calls appropriate transport message handler
  40  *
  41  *
  42  **/
  43 static void
  44 scsi_nl_rcv_msg(struct sk_buff *skb)
  45 {
  46         struct nlmsghdr *nlh;
  47         struct scsi_nl_hdr *hdr;
  48         uint32_t rlen;
  49         int err;
  50
  51         while (skb->len >= NLMSG_SPACE(0)) {
  52                 err = 0;
  53
  54                 nlh = nlmsg_hdr(skb);
  55                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
  56                     (skb->len < nlh->nlmsg_len)) {
  57                         printk(KERN_WARNING "%s: discarding partial skb\n",
  58                                  __func__);
  59                         return;
  60                 }
  61
  62                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
  63                 if (rlen > skb->len)
  64                         rlen = skb->len;
  65
  66                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
  67                         err = -EBADMSG;
  68                         return;
  69                 }
  70
  71                 hdr = NLMSG_DATA(nlh);
  72                 if ((hdr->version != SCSI_NL_VERSION) ||
  73                     (hdr->magic != SCSI_NL_MAGIC)) {
  74                         err = -EPROTOTYPE;
  75                         goto next_msg;
  76                 }
  77
  78                 if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
  79                         err = -EPERM;
  80                         goto next_msg;
  81                 }
  82
  83                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
  84                         printk(KERN_WARNING "%s: discarding partial message\n",
  85                                  __func__);
  86                         return;
  87                 }
  88
  89                 /*
  90                  * We currently don't support anyone sending us a message
  91                  */
  92
  93 next_msg:
  94                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
  95                         netlink_ack(skb, nlh, err);
  96
  97                 skb_pull(skb, rlen);
  98         }
  99 }
 100
 101
 102 /**
 103  * scsi_nl_rcv_event - Event handler for a netlink socket.
 104  * @this:               event notifier block
 105  * @event:              event type
 106  * @ptr:                event payload
 107  *
 108  **/
 109 static int
 110 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
 111 {
 112         struct netlink_notify *n = ptr;
 113
 114         if (n->protocol != NETLINK_SCSITRANSPORT)
 115                 return NOTIFY_DONE;
 116
 117         /*
 118          * Currently, we are not tracking PID's, etc. There is nothing
 119          * to handle.
 120          */
 121
 122         return NOTIFY_DONE;
 123 }
 124
 125 static struct notifier_block scsi_netlink_notifier = {
 126         .notifier_call  = scsi_nl_rcv_event,
 127 };
 128
 129
 130 /**
 131  * scsi_netlink_init - Called by SCSI subsystem to intialize the SCSI transport netlink interface
 132  *
 133  **/
 134 void
 135 scsi_netlink_init(void)
 136 {
 137         int error;
 138
 139         error = netlink_register_notifier(&scsi_netlink_notifier);
 140         if (error) {
 141                 printk(KERN_ERR "%s: register of event handler failed - %d\n",
 142                                 __func__, error);
 143                 return;
 144         }
 145
 146         scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
 147                                 SCSI_NL_GRP_CNT, scsi_nl_rcv_msg, NULL,
 148                                 THIS_MODULE);
 149         if (!scsi_nl_sock) {
 150                 printk(KERN_ERR "%s: register of recieve handler failed\n",
 151                                 __func__);
 152                 netlink_unregister_notifier(&scsi_netlink_notifier);
 153         }
 154
 155         return;
 156 }
 157
 158
 159 /**
 160  * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
 161  *
 162  **/
 163 void
 164 scsi_netlink_exit(void)
 165 {
 166         if (scsi_nl_sock) {
 167                 netlink_kernel_release(scsi_nl_sock);
 168                 netlink_unregister_notifier(&scsi_netlink_notifier);
 169         }
 170
 171         return;
 172 }
 173
 174