drivers/staging/gdm72xx/netlink_k.c

   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 #include <linux/module.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/netlink.h>
  17 #include <asm/byteorder.h>
  18 #include <net/sock.h>
  19
  20 #if !defined(NLMSG_HDRLEN)
  21 #define NLMSG_HDRLEN     ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
  22 #endif
  23
  24 #define ND_MAX_GROUP                    30
  25 #define ND_IFINDEX_LEN                  sizeof(int)
  26 #define ND_NLMSG_SPACE(len)             (NLMSG_SPACE(len) + ND_IFINDEX_LEN)
  27 #define ND_NLMSG_DATA(nlh) \
  28         ((void *)((char *)NLMSG_DATA(nlh) + ND_IFINDEX_LEN))
  29 #define ND_NLMSG_S_LEN(len)             (len+ND_IFINDEX_LEN)
  30 #define ND_NLMSG_R_LEN(nlh)             (nlh->nlmsg_len-ND_IFINDEX_LEN)
  31 #define ND_NLMSG_IFIDX(nlh)             NLMSG_DATA(nlh)
  32 #define ND_MAX_MSG_LEN                  8096
  33
  34 #if defined(DEFINE_MUTEX)
  35 static DEFINE_MUTEX(netlink_mutex);
  36 #else
  37 static struct semaphore netlink_mutex;
  38 #define mutex_lock(x)           down(x)
  39 #define mutex_unlock(x)         up(x)
  40 #endif
  41
  42 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
  43
  44 static void netlink_rcv_cb(struct sk_buff *skb)
  45 {
  46         struct nlmsghdr *nlh;
  47         struct net_device *dev;
  48         u32 mlen;
  49         void *msg;
  50         int ifindex;
  51
  52         if (skb->len >= NLMSG_SPACE(0)) {
  53                 nlh = (struct nlmsghdr *)skb->data;
  54
  55                 if (skb->len < nlh->nlmsg_len ||
  56                 nlh->nlmsg_len > ND_MAX_MSG_LEN) {
  57                         printk(KERN_ERR "Invalid length (%d,%d)\n", skb->len,
  58                                 nlh->nlmsg_len);
  59                         return;
  60                 }
  61
  62                 memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN);
  63                 msg = ND_NLMSG_DATA(nlh);
  64                 mlen = ND_NLMSG_R_LEN(nlh);
  65
  66                 if (rcv_cb) {
  67                         dev = dev_get_by_index(&init_net, ifindex);
  68                         if (dev) {
  69                                 rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
  70                                 dev_put(dev);
  71                         } else
  72                                 printk(KERN_ERR "dev_get_by_index(%d) "
  73                                         "is not found.\n", ifindex);
  74                 } else
  75                         printk(KERN_ERR "Unregistered Callback\n");
  76         }
  77 }
  78
  79 static void netlink_rcv(struct sk_buff *skb)
  80 {
  81         mutex_lock(&netlink_mutex);
  82         netlink_rcv_cb(skb);
  83         mutex_unlock(&netlink_mutex);
  84 }
  85
  86 struct sock *netlink_init(int unit, void (*cb)(struct net_device *dev, u16 type,
  87                                                 void *msg, int len))
  88 {
  89         struct sock *sock;
  90         struct netlink_kernel_cfg cfg = {
  91                 .input  = netlink_rcv,
  92         };
  93
  94 #if !defined(DEFINE_MUTEX)
  95         init_MUTEX(&netlink_mutex);
  96 #endif
  97
  98         sock = netlink_kernel_create(&init_net, unit, &cfg);
  99
 100         if (sock)
 101                 rcv_cb = cb;
 102
 103         return sock;
 104 }
 105
 106 void netlink_exit(struct sock *sock)
 107 {
 108         netlink_kernel_release(sock);
 109 }
 110
 111 int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
 112 {
 113         static u32 seq;
 114         struct sk_buff *skb = NULL;
 115         struct nlmsghdr *nlh;
 116         int ret = 0;
 117
 118         if (group > ND_MAX_GROUP) {
 119                 printk(KERN_ERR "Group %d is invalied.\n", group);
 120                 printk(KERN_ERR "Valid group is 0 ~ %d.\n", ND_MAX_GROUP);
 121                 return -EINVAL;
 122         }
 123
 124         skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC);
 125         if (!skb) {
 126                 printk(KERN_ERR "netlink_broadcast ret=%d\n", ret);
 127                 return -ENOMEM;
 128         }
 129
 130         seq++;
 131         nlh = nlmsg_put(skb, 0, seq, type, len, 0);
 132         if (!nlh) {
 133                 kfree_skb(skb);
 134                 return -EMSGSIZE;
 135         }
 136         memcpy(nlmsg_data(nlh), msg, len);
 137
 138         NETLINK_CB(skb).portid = 0;
 139         NETLINK_CB(skb).dst_group = 0;
 140
 141         ret = netlink_broadcast(sock, skb, 0, group+1, GFP_ATOMIC);
 142
 143         if (!ret)
 144                 return len;
 145         else {
 146                 if (ret != -ESRCH) {
 147                         printk(KERN_ERR "netlink_broadcast g=%d, t=%d, l=%d, r=%d\n",
 148                                 group, type, len, ret);
 149                 }
 150                 ret = 0;
 151         }
 152         return ret;
 153 }