scsi_netlink.c

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/*
 *  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);

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_SPACE(0)) {
        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\n",
                 __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 (!capable(CAP_SYS_ADMIN)) {
            err = -EPERM;
            goto next_msg;
        }

        if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
            printk(KERN_WARNING "%s: discarding partial message\n",
                 __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\n",
                       __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);
    }
}

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\n",
                __func__);
        return;
    }

    return;
}


void
scsi_netlink_exit(void)
{
    if (scsi_nl_sock) {
        netlink_kernel_release(scsi_nl_sock);
    }

    return;
}