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 -
  36  *    Receive message handler. Extracts message from a receive buffer.
  37  *    Validates message header and calls appropriate transport message handler
  38  *
  39  * @skb:                socket receive buffer
  40  *
  41  **/
  42 static void
  43 scsi_nl_rcv_msg(struct sk_buff *skb)
  44 {
  45         struct nlmsghdr *nlh;
  46         struct scsi_nl_hdr *hdr;
  47         uint32_t rlen;
  48         int err;
  49
  50         while (skb->len >= NLMSG_SPACE(0)) {
  51                 err = 0;
  52
  53                 nlh = nlmsg_hdr(skb);
  54                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
  55                     (skb->len < nlh->nlmsg_len)) {
  56                         printk(KERN_WARNING "%s: discarding partial skb\n",
  57                                  __FUNCTION__);
  58                         return;
  59                 }
  60
  61                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
  62                 if (rlen > skb->len)
  63                         rlen = skb->len;
  64
  65                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
  66                         err = -EBADMSG;
  67                         goto next_msg;
  68                 }
  69
  70                 hdr = NLMSG_DATA(nlh);
  71                 if ((hdr->version != SCSI_NL_VERSION) ||
  72                     (hdr->magic != SCSI_NL_MAGIC)) {
  73                         err = -EPROTOTYPE;
  74                         goto next_msg;
  75                 }
  76
  77                 if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
  78                         err = -EPERM;
  79                         goto next_msg;
  80                 }
  81
  82                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
  83                         printk(KERN_WARNING "%s: discarding partial message\n",
  84                                  __FUNCTION__);
  85                         return;
  86                 }
  87
  88                 /*
  89                  * We currently don't support anyone sending us a message
  90                  */
  91
  92 next_msg:
  93                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
  94                         netlink_ack(skb, nlh, err);
  95
  96                 skb_pull(skb, rlen);
  97         }
  98 }
  99
 100
 101 /**
 102  * scsi_nl_rcv_msg -
 103  *    Receive handler for a socket. Extracts a received message buffer from
 104  *    the socket, and starts message processing.
 105  *
 106  * @sk:         socket
 107  * @len:        unused
 108  *
 109  **/
 110 static void
 111 scsi_nl_rcv(struct sock *sk, int len)
 112 {
 113         struct sk_buff *skb;
 114
 115         while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
 116                 scsi_nl_rcv_msg(skb);
 117                 kfree_skb(skb);
 118         }
 119 }
 120
 121
 122 /**
 123  * scsi_nl_rcv_event -
 124  *    Event handler for a netlink socket.
 125  *
 126  * @this:               event notifier block
 127  * @event:              event type
 128  * @ptr:                event payload
 129  *
 130  **/
 131 static int
 132 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
 133 {
 134         struct netlink_notify *n = ptr;
 135
 136         if (n->protocol != NETLINK_SCSITRANSPORT)
 137                 return NOTIFY_DONE;
 138
 139         /*
 140          * Currently, we are not tracking PID's, etc. There is nothing
 141          * to handle.
 142          */
 143
 144         return NOTIFY_DONE;
 145 }
 146
 147 static struct notifier_block scsi_netlink_notifier = {
 148         .notifier_call  = scsi_nl_rcv_event,
 149 };
 150
 151
 152 /**
 153  * scsi_netlink_init -
 154  *    Called by SCSI subsystem to intialize the SCSI transport netlink
 155  *    interface
 156  *
 157  **/
 158 void
 159 scsi_netlink_init(void)
 160 {
 161         int error;
 162
 163         error = netlink_register_notifier(&scsi_netlink_notifier);
 164         if (error) {
 165                 printk(KERN_ERR "%s: register of event handler failed - %d\n",
 166                                 __FUNCTION__, error);
 167                 return;
 168         }
 169
 170         scsi_nl_sock = netlink_kernel_create(NETLINK_SCSITRANSPORT,
 171                                 SCSI_NL_GRP_CNT, scsi_nl_rcv, NULL,
 172                                 THIS_MODULE);
 173         if (!scsi_nl_sock) {
 174                 printk(KERN_ERR "%s: register of recieve handler failed\n",
 175                                 __FUNCTION__);
 176                 netlink_unregister_notifier(&scsi_netlink_notifier);
 177         }
 178
 179         return;
 180 }
 181
 182
 183 /**
 184  * scsi_netlink_exit -
 185  *    Called by SCSI subsystem to disable the SCSI transport netlink
 186  *    interface
 187  *
 188  **/
 189 void
 190 scsi_netlink_exit(void)
 191 {
 192         if (scsi_nl_sock) {
 193                 sock_release(scsi_nl_sock->sk_socket);
 194                 netlink_unregister_notifier(&scsi_netlink_notifier);
 195         }
 196
 197         return;
 198 }
 199
 200