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/*
* Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/etherdevice.h>
#include <linux/netlink.h>
#include <asm/byteorder.h>
#include <net/sock.h>
#include "netlink_k.h"
static DEFINE_MUTEX(netlink_mutex);
#define ND_MAX_GROUP 30
#define ND_IFINDEX_LEN sizeof(int)
#define ND_NLMSG_SPACE(len) (NLMSG_SPACE(len) + ND_IFINDEX_LEN)
#define ND_NLMSG_DATA(nlh) ((void *)((char *)NLMSG_DATA(nlh) + \
ND_IFINDEX_LEN))
#define ND_NLMSG_S_LEN(len) (len + ND_IFINDEX_LEN)
#define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len - ND_IFINDEX_LEN)
#define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh)
#define ND_MAX_MSG_LEN (1024 * 32)
static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
static void netlink_rcv_cb(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
struct net_device *dev;
u32 mlen;
void *msg;
int ifindex;
if (!rcv_cb) {
pr_err("nl cb - unregistered\n");
return;
}
if (skb->len < NLMSG_HDRLEN) {
pr_err("nl cb - invalid skb length\n");
return;
}
nlh = (struct nlmsghdr *)skb->data;
if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) {
pr_err("nl cb - invalid length (%d,%d)\n",
skb->len, nlh->nlmsg_len);
return;
}
memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN);
msg = ND_NLMSG_DATA(nlh);
mlen = ND_NLMSG_R_LEN(nlh);
dev = dev_get_by_index(&init_net, ifindex);
if (dev) {
rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
dev_put(dev);
} else {
pr_err("nl cb - dev (%d) not found\n", ifindex);
}
}
static void netlink_rcv(struct sk_buff *skb)
{
mutex_lock(&netlink_mutex);
netlink_rcv_cb(skb);
mutex_unlock(&netlink_mutex);
}
struct sock *netlink_init(int unit,
void (*cb)(struct net_device *dev, u16 type,
void *msg, int len))
{
struct sock *sock;
struct netlink_kernel_cfg cfg = {
.input = netlink_rcv,
};
sock = netlink_kernel_create(&init_net, unit, &cfg);
if (sock)
rcv_cb = cb;
return sock;
}
int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
{
static u32 seq;
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh;
int ret = 0;
if (group > ND_MAX_GROUP)
return -EINVAL;
if (!netlink_has_listeners(sock, group + 1))
return -ESRCH;
skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC);
if (!skb)
return -ENOMEM;
seq++;
nlh = nlmsg_put(skb, 0, seq, type, len, 0);
memcpy(NLMSG_DATA(nlh), msg, len);
NETLINK_CB(skb).portid = 0;
NETLINK_CB(skb).dst_group = 0;
ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC);
if (!ret)
return len;
if (ret != -ESRCH)
pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n",
group, type, len, ret);
else if (netlink_has_listeners(sock, group + 1))
return -EAGAIN;
return ret;
}
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