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 <linux/delay.h>
25#include <linux/slab.h>
26#include <linux/export.h>
27#include <net/sock.h>
28#include <net/netlink.h>
29
30#include <scsi/scsi_netlink.h>
31#include "scsi_priv.h"
32
33struct sock *scsi_nl_sock = NULL;
34EXPORT_SYMBOL_GPL(scsi_nl_sock);
35
36/**
37 * scsi_nl_rcv_msg - Receive message handler.
38 * @skb:		socket receive buffer
39 *
40 * Description: Extracts message from a receive buffer.
41 *    Validates message header and calls appropriate transport message handler
42 *
43 *
44 **/
45static void
46scsi_nl_rcv_msg(struct sk_buff *skb)
47{
48	struct nlmsghdr *nlh;
49	struct scsi_nl_hdr *hdr;
50	u32 rlen;
51	int err, tport;
52
53	while (skb->len >= NLMSG_HDRLEN) {
54		err = 0;
55
56		nlh = nlmsg_hdr(skb);
57		if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
58		    (skb->len < nlh->nlmsg_len)) {
59			printk(KERN_WARNING "%s: discarding partial skb\n",
60				 __func__);
61			return;
62		}
63
64		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
65		if (rlen > skb->len)
66			rlen = skb->len;
67
68		if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
69			err = -EBADMSG;
70			goto next_msg;
71		}
72
73		hdr = nlmsg_data(nlh);
74		if ((hdr->version != SCSI_NL_VERSION) ||
75		    (hdr->magic != SCSI_NL_MAGIC)) {
76			err = -EPROTOTYPE;
77			goto next_msg;
78		}
79
80		if (!netlink_capable(skb, CAP_SYS_ADMIN)) {
81			err = -EPERM;
82			goto next_msg;
83		}
84
85		if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
86			printk(KERN_WARNING "%s: discarding partial message\n",
87				 __func__);
88			goto next_msg;
89		}
90
91		/*
92		 * Deliver message to the appropriate transport
93		 */
94		tport = hdr->transport;
95		if (tport == SCSI_NL_TRANSPORT) {
96			switch (hdr->msgtype) {
97			case SCSI_NL_SHOST_VENDOR:
98				/* Locate the driver that corresponds to the message */
99				err = -ESRCH;
100				break;
101			default:
102				err = -EBADR;
103				break;
104			}
105			if (err)
106				printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
107				       __func__, hdr->msgtype, err);
108		}
109		else
110			err = -ENOENT;
111
112next_msg:
113		if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
114			netlink_ack(skb, nlh, err);
115
116		skb_pull(skb, rlen);
117	}
118}
119
120/**
121 * scsi_netlink_init - Called by SCSI subsystem to initialize
122 * 	the SCSI transport netlink interface
123 *
124 **/
125void
126scsi_netlink_init(void)
127{
128	struct netlink_kernel_cfg cfg = {
129		.input	= scsi_nl_rcv_msg,
130		.groups	= SCSI_NL_GRP_CNT,
131	};
132
133	scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
134					     &cfg);
135	if (!scsi_nl_sock) {
136		printk(KERN_ERR "%s: register of receive handler failed\n",
137				__func__);
138		return;
139	}
140
141	return;
142}
143
144
145/**
146 * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
147 *
148 **/
149void
150scsi_netlink_exit(void)
151{
152	if (scsi_nl_sock) {
153		netlink_kernel_release(scsi_nl_sock);
154	}
155
156	return;
157}
158
159