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