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)
38 static DEFINE_MUTEX(netlink_mutex);
39 #else
40 static struct semaphore netlink_mutex;
41 #define mutex_lock(x) down(x)
42 #define mutex_unlock(x) up(x)
43 #endif
44
45 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
46
netlink_rcv_cb(struct sk_buff * skb)47 static 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
netlink_rcv(struct sk_buff * skb)84 static 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
netlink_init(int unit,void (* cb)(struct net_device * dev,u16 type,void * msg,int len))91 struct 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
netlink_exit(struct sock * sock)111 void netlink_exit(struct sock *sock)
112 {
113 netlink_kernel_release(sock);
114 }
115
netlink_send(struct sock * sock,int group,u16 type,void * msg,int len)116 int 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 invalid.\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