cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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netlink_k.c (2897B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved. */
      3
      4#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      5
      6#include <linux/export.h>
      7#include <linux/mutex.h>
      8#include <linux/etherdevice.h>
      9#include <linux/netlink.h>
     10#include <asm/byteorder.h>
     11#include <net/sock.h>
     12
     13#include "netlink_k.h"
     14
     15static DEFINE_MUTEX(netlink_mutex);
     16
     17#define ND_MAX_GROUP		30
     18#define ND_IFINDEX_LEN		sizeof(int)
     19#define ND_NLMSG_SPACE(len)	(NLMSG_SPACE(len) + ND_IFINDEX_LEN)
     20#define ND_NLMSG_DATA(nlh)	((void *)((char *)NLMSG_DATA(nlh) + \
     21						  ND_IFINDEX_LEN))
     22#define ND_NLMSG_S_LEN(len)	((len) + ND_IFINDEX_LEN)
     23#define ND_NLMSG_R_LEN(nlh)	((nlh)->nlmsg_len - ND_IFINDEX_LEN)
     24#define ND_NLMSG_IFIDX(nlh)	NLMSG_DATA(nlh)
     25#define ND_MAX_MSG_LEN		(1024 * 32)
     26
     27static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len);
     28
     29static void netlink_rcv_cb(struct sk_buff *skb)
     30{
     31	struct nlmsghdr	*nlh;
     32	struct net_device *dev;
     33	u32 mlen;
     34	void *msg;
     35	int ifindex;
     36
     37	if (!rcv_cb) {
     38		pr_err("nl cb - unregistered\n");
     39		return;
     40	}
     41
     42	if (skb->len < NLMSG_HDRLEN) {
     43		pr_err("nl cb - invalid skb length\n");
     44		return;
     45	}
     46
     47	nlh = (struct nlmsghdr *)skb->data;
     48
     49	if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) {
     50		pr_err("nl cb - invalid length (%d,%d)\n",
     51		       skb->len, nlh->nlmsg_len);
     52		return;
     53	}
     54
     55	memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN);
     56	msg = ND_NLMSG_DATA(nlh);
     57	mlen = ND_NLMSG_R_LEN(nlh);
     58
     59	dev = dev_get_by_index(&init_net, ifindex);
     60	if (dev) {
     61		rcv_cb(dev, nlh->nlmsg_type, msg, mlen);
     62		dev_put(dev);
     63	} else {
     64		pr_err("nl cb - dev (%d) not found\n", ifindex);
     65	}
     66}
     67
     68static void netlink_rcv(struct sk_buff *skb)
     69{
     70	mutex_lock(&netlink_mutex);
     71	netlink_rcv_cb(skb);
     72	mutex_unlock(&netlink_mutex);
     73}
     74
     75struct sock *netlink_init(int unit,
     76			  void (*cb)(struct net_device *dev, u16 type,
     77				     void *msg, int len))
     78{
     79	struct sock *sock;
     80	struct netlink_kernel_cfg cfg = {
     81		.input  = netlink_rcv,
     82	};
     83
     84	sock = netlink_kernel_create(&init_net, unit, &cfg);
     85
     86	if (sock)
     87		rcv_cb = cb;
     88
     89	return sock;
     90}
     91
     92int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len,
     93		 struct net_device *dev)
     94{
     95	static u32 seq;
     96	struct sk_buff *skb = NULL;
     97	struct nlmsghdr *nlh;
     98	int ret = 0;
     99
    100	if (group > ND_MAX_GROUP)
    101		return -EINVAL;
    102
    103	if (!netlink_has_listeners(sock, group + 1))
    104		return -ESRCH;
    105
    106	skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC);
    107	if (!skb)
    108		return -ENOMEM;
    109
    110	seq++;
    111
    112	nlh = nlmsg_put(skb, 0, seq, type, len, 0);
    113	memcpy(NLMSG_DATA(nlh), msg, len);
    114	NETLINK_CB(skb).portid = 0;
    115	NETLINK_CB(skb).dst_group = 0;
    116
    117	ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC);
    118	if (!ret)
    119		return len;
    120
    121	if (ret != -ESRCH)
    122		netdev_err(dev, "nl broadcast g=%d, t=%d, l=%d, r=%d\n",
    123			   group, type, len, ret);
    124	else if (netlink_has_listeners(sock, group + 1))
    125		return -EAGAIN;
    126
    127	return ret;
    128}