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 #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
  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
  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
  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
 111 void netlink_exit(struct sock *sock)
 112 {
 113         netlink_kernel_release(sock);
 114 }
 115
 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 }