LXR linux/drivers/staging/gdm724x/netlink

   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/export.h>
  17#include <linux/mutex.h>
  18#include <linux/etherdevice.h>
  19#include <linux/netlink.h>
  20#include <asm/byteorder.h>
  21#include <net/sock.h>
  22
  23#include "netlink_k.h"
  24
  25static DEFINE_MUTEX(netlink_mutex);
  26
  27#define ND_MAX_GROUP            30
  28#define ND_IFINDEX_LEN          sizeof(int)
  29#define ND_NLMSG_SPACE(len)     (NLMSG_SPACE(len) + ND_IFINDEX_LEN)
  30#define ND_NLMSG_DATA(nlh)      ((void *)((char *)NLMSG_DATA(nlh) + \
  31                                                  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          (1024 * 32)
  36
  37static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
  38
  39static void netlink_rcv_cb(struct sk_buff *skb)
  40{
  41        struct nlmsghdr *nlh;
  42        struct net_device *dev;
  43        u32 mlen;
  44        void *msg;
  45        int ifindex;
  46
  47        if (!rcv_cb) {
  48                pr_err("nl cb - unregistered\n");
  49                return;
  50        }
  51
  52        if (skb->len < NLMSG_HDRLEN) {
  53                pr_err("nl cb - invalid skb length\n");
  54                return;
  55        }
  56
  57        nlh = (struct nlmsghdr *)skb->data;
  58
  59        if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) {
  60                pr_err("nl cb - 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        dev = dev_get_by_index(&init_net, ifindex);
  70        if (dev) {
  71                rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
  72                dev_put(dev);
  73        } else {
  74                pr_err("nl cb - dev (%d) not found\n", ifindex);
  75        }
  76}
  77
  78static void netlink_rcv(struct sk_buff *skb)
  79{
  80        mutex_lock(&netlink_mutex);
  81        netlink_rcv_cb(skb);
  82        mutex_unlock(&netlink_mutex);
  83}
  84
  85struct sock *netlink_init(int unit,
  86                          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        sock = netlink_kernel_create(&init_net, unit, &cfg);
  95
  96        if (sock)
  97                rcv_cb = cb;
  98
  99        return sock;
 100}
 101
 102int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
 103{
 104        static u32 seq;
 105        struct sk_buff *skb = NULL;
 106        struct nlmsghdr *nlh;
 107        int ret = 0;
 108
 109        if (group > ND_MAX_GROUP)
 110                return -EINVAL;
 111
 112        if (!netlink_has_listeners(sock, group + 1))
 113                return -ESRCH;
 114
 115        skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC);
 116        if (!skb)
 117                return -ENOMEM;
 118
 119        seq++;
 120
 121        nlh = nlmsg_put(skb, 0, seq, type, len, 0);
 122        memcpy(NLMSG_DATA(nlh), msg, len);
 123        NETLINK_CB(skb).portid = 0;
 124        NETLINK_CB(skb).dst_group = 0;
 125
 126        ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC);
 127        if (!ret)
 128                return len;
 129
 130        if (ret != -ESRCH)
 131                pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n",
 132                       group, type, len, ret);
 133        else if (netlink_has_listeners(sock, group + 1))
 134                return -EAGAIN;
 135
 136        return ret;
 137}
 138