1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  scsi_netlink.c  - SCSI Transport Netlink Interface
4 *
5 *  Copyright (C) 2006   James Smart, Emulex Corporation
6 */
7#include <linux/time.h>
8#include <linux/jiffies.h>
9#include <linux/security.h>
10#include <linux/delay.h>
11#include <linux/slab.h>
12#include <linux/export.h>
13#include <net/sock.h>
14#include <net/netlink.h>
15
16#include <scsi/scsi_netlink.h>
17#include "scsi_priv.h"
18
19struct sock *scsi_nl_sock = NULL;
20EXPORT_SYMBOL_GPL(scsi_nl_sock);
21
22/**
23 * scsi_nl_rcv_msg - Receive message handler.
24 * @skb:		socket receive buffer
25 *
26 * Description: Extracts message from a receive buffer.
27 *    Validates message header and calls appropriate transport message handler
28 *
29 *
30 **/
31static void
32scsi_nl_rcv_msg(struct sk_buff *skb)
33{
34	struct nlmsghdr *nlh;
35	struct scsi_nl_hdr *hdr;
36	u32 rlen;
37	int err, tport;
38
39	while (skb->len >= NLMSG_HDRLEN) {
40		err = 0;
41
42		nlh = nlmsg_hdr(skb);
43		if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
44		    (skb->len < nlh->nlmsg_len)) {
45			printk(KERN_WARNING "%s: discarding partial skb\n",
46				 __func__);
47			return;
48		}
49
50		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
51		if (rlen > skb->len)
52			rlen = skb->len;
53
54		if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
55			err = -EBADMSG;
56			goto next_msg;
57		}
58
59		hdr = nlmsg_data(nlh);
60		if ((hdr->version != SCSI_NL_VERSION) ||
61		    (hdr->magic != SCSI_NL_MAGIC)) {
62			err = -EPROTOTYPE;
63			goto next_msg;
64		}
65
66		if (!netlink_capable(skb, CAP_SYS_ADMIN)) {
67			err = -EPERM;
68			goto next_msg;
69		}
70
71		if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
72			printk(KERN_WARNING "%s: discarding partial message\n",
73				 __func__);
74			goto next_msg;
75		}
76
77		/*
78		 * Deliver message to the appropriate transport
79		 */
80		tport = hdr->transport;
81		if (tport == SCSI_NL_TRANSPORT) {
82			switch (hdr->msgtype) {
83			case SCSI_NL_SHOST_VENDOR:
84				/* Locate the driver that corresponds to the message */
85				err = -ESRCH;
86				break;
87			default:
88				err = -EBADR;
89				break;
90			}
91			if (err)
92				printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
93				       __func__, hdr->msgtype, err);
94		}
95		else
96			err = -ENOENT;
97
98next_msg:
99		if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
100			netlink_ack(skb, nlh, err, NULL);
101
102		skb_pull(skb, rlen);
103	}
104}
105
106/**
107 * scsi_netlink_init - Called by SCSI subsystem to initialize
108 * 	the SCSI transport netlink interface
109 *
110 **/
111void
112scsi_netlink_init(void)
113{
114	struct netlink_kernel_cfg cfg = {
115		.input	= scsi_nl_rcv_msg,
116		.groups	= SCSI_NL_GRP_CNT,
117	};
118
119	scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
120					     &cfg);
121	if (!scsi_nl_sock) {
122		printk(KERN_ERR "%s: register of receive handler failed\n",
123				__func__);
124		return;
125	}
126
127	return;
128}
129
130
131/**
132 * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
133 *
134 **/
135void
136scsi_netlink_exit(void)
137{
138	if (scsi_nl_sock) {
139		netlink_kernel_release(scsi_nl_sock);
140	}
141
142	return;
143}
144
145