1/*
2 * Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/etherdevice.h>
18#include <net/netlink.h>
19#include <asm/byteorder.h>
20#include <net/sock.h>
21#include "netlink_k.h"
22
23#if !defined(NLMSG_HDRLEN)
24#define NLMSG_HDRLEN	 ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
25#endif
26
27#define ND_MAX_GROUP			30
28#define ND_IFINDEX_LEN			sizeof(int)
29#define ND_NLMSG_SPACE(len)		(nlmsg_total_size(len) + ND_IFINDEX_LEN)
30#define ND_NLMSG_DATA(nlh) \
31	((void *)((char *)nlmsg_data(nlh) + ND_IFINDEX_LEN))
32#define ND_NLMSG_S_LEN(len)		(len+ND_IFINDEX_LEN)
33#define ND_NLMSG_R_LEN(nlh)		(nlh->nlmsg_len-ND_IFINDEX_LEN)
34#define ND_NLMSG_IFIDX(nlh)		nlmsg_data(nlh)
35#define ND_MAX_MSG_LEN			8096
36
37#if defined(DEFINE_MUTEX)
38static DEFINE_MUTEX(netlink_mutex);
39#else
40static struct semaphore netlink_mutex;
41#define mutex_lock(x)		down(x)
42#define mutex_unlock(x)		up(x)
43#endif
44
45static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
46
47static void netlink_rcv_cb(struct sk_buff *skb)
48{
49	struct nlmsghdr *nlh;
50	struct net_device *dev;
51	u32 mlen;
52	void *msg;
53	int ifindex;
54
55	if (skb->len >= NLMSG_HDRLEN) {
56		nlh = (struct nlmsghdr *)skb->data;
57
58		if (skb->len < nlh->nlmsg_len ||
59		    nlh->nlmsg_len > ND_MAX_MSG_LEN) {
60			netdev_err(skb->dev, "Invalid length (%d,%d)\n",
61				   skb->len, nlh->nlmsg_len);
62			return;
63		}
64
65		memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN);
66		msg = ND_NLMSG_DATA(nlh);
67		mlen = ND_NLMSG_R_LEN(nlh);
68
69		if (rcv_cb) {
70			dev = dev_get_by_index(&init_net, ifindex);
71			if (dev) {
72				rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
73				dev_put(dev);
74			} else
75				netdev_err(skb->dev,
76					   "dev_get_by_index(%d) is not found.\n",
77					   ifindex);
78		} else {
79			netdev_err(skb->dev, "Unregistered Callback\n");
80		}
81	}
82}
83
84static void netlink_rcv(struct sk_buff *skb)
85{
86	mutex_lock(&netlink_mutex);
87	netlink_rcv_cb(skb);
88	mutex_unlock(&netlink_mutex);
89}
90
91struct sock *netlink_init(int unit, void (*cb)(struct net_device *dev, u16 type,
92					       void *msg, int len))
93{
94	struct sock *sock;
95	struct netlink_kernel_cfg cfg = {
96		.input  = netlink_rcv,
97	};
98
99#if !defined(DEFINE_MUTEX)
100	init_MUTEX(&netlink_mutex);
101#endif
102
103	sock = netlink_kernel_create(&init_net, unit, &cfg);
104
105	if (sock)
106		rcv_cb = cb;
107
108	return sock;
109}
110
111void netlink_exit(struct sock *sock)
112{
113	netlink_kernel_release(sock);
114}
115
116int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
117{
118	static u32 seq;
119	struct sk_buff *skb = NULL;
120	struct nlmsghdr *nlh;
121	int ret = 0;
122
123	if (group > ND_MAX_GROUP) {
124		pr_err("Group %d is invalied.\n", group);
125		pr_err("Valid group is 0 ~ %d.\n", ND_MAX_GROUP);
126		return -EINVAL;
127	}
128
129	skb = nlmsg_new(len, GFP_ATOMIC);
130	if (!skb) {
131		pr_err("netlink_broadcast ret=%d\n", ret);
132		return -ENOMEM;
133	}
134
135	seq++;
136	nlh = nlmsg_put(skb, 0, seq, type, len, 0);
137	if (!nlh) {
138		kfree_skb(skb);
139		return -EMSGSIZE;
140	}
141	memcpy(nlmsg_data(nlh), msg, len);
142
143	NETLINK_CB(skb).portid = 0;
144	NETLINK_CB(skb).dst_group = 0;
145
146	ret = netlink_broadcast(sock, skb, 0, group+1, GFP_ATOMIC);
147
148	if (!ret)
149		return len;
150	if (ret != -ESRCH) {
151		pr_err("netlink_broadcast g=%d, t=%d, l=%d, r=%d\n",
152		       group, type, len, ret);
153	}
154	ret = 0;
155	return ret;
156}
157