// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved. */
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/export.h>
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#include <linux/mutex.h>
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#include <linux/etherdevice.h>
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#include <linux/netlink.h>
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#include <asm/byteorder.h>
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#include <net/sock.h>
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#include "netlink_k.h"
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static DEFINE_MUTEX(netlink_mutex);
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#define ND_MAX_GROUP 30
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#define ND_IFINDEX_LEN sizeof(int)
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#define ND_NLMSG_SPACE(len) (NLMSG_SPACE(len) + ND_IFINDEX_LEN)
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#define ND_NLMSG_DATA(nlh) ((void *)((char *)NLMSG_DATA(nlh) + \
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ND_IFINDEX_LEN))
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#define ND_NLMSG_S_LEN(len) (len + ND_IFINDEX_LEN)
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#define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len - ND_IFINDEX_LEN)
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#define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh)
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#define ND_MAX_MSG_LEN (1024 * 32)
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static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
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static void netlink_rcv_cb(struct sk_buff *skb)
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{
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struct nlmsghdr *nlh;
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struct net_device *dev;
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u32 mlen;
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void *msg;
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int ifindex;
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if (!rcv_cb) {
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pr_err("nl cb - unregistered\n");
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return;
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}
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if (skb->len < NLMSG_HDRLEN) {
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pr_err("nl cb - invalid skb length\n");
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return;
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}
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nlh = (struct nlmsghdr *)skb->data;
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if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) {
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pr_err("nl cb - invalid length (%d,%d)\n",
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skb->len, nlh->nlmsg_len);
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return;
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}
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memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN);
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msg = ND_NLMSG_DATA(nlh);
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mlen = ND_NLMSG_R_LEN(nlh);
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dev = dev_get_by_index(&init_net, ifindex);
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if (dev) {
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rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
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dev_put(dev);
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} else {
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pr_err("nl cb - dev (%d) not found\n", ifindex);
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}
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}
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static void netlink_rcv(struct sk_buff *skb)
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{
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mutex_lock(&netlink_mutex);
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netlink_rcv_cb(skb);
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mutex_unlock(&netlink_mutex);
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}
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struct sock *netlink_init(int unit,
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void (*cb)(struct net_device *dev, u16 type,
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void *msg, int len))
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{
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struct sock *sock;
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struct netlink_kernel_cfg cfg = {
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.input = netlink_rcv,
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};
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sock = netlink_kernel_create(&init_net, unit, &cfg);
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if (sock)
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rcv_cb = cb;
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return sock;
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}
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int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
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{
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static u32 seq;
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struct sk_buff *skb = NULL;
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struct nlmsghdr *nlh;
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int ret = 0;
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if (group > ND_MAX_GROUP)
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return -EINVAL;
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if (!netlink_has_listeners(sock, group + 1))
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return -ESRCH;
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skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC);
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if (!skb)
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return -ENOMEM;
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seq++;
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nlh = nlmsg_put(skb, 0, seq, type, len, 0);
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memcpy(NLMSG_DATA(nlh), msg, len);
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NETLINK_CB(skb).portid = 0;
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NETLINK_CB(skb).dst_group = 0;
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ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC);
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if (!ret)
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return len;
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if (ret != -ESRCH)
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pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n",
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group, type, len, ret);
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else if (netlink_has_listeners(sock, group + 1))
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return -EAGAIN;
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return ret;
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}
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