path: root/net/can/raw.c

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/* raw.c - Raw sockets for protocol family CAN
 *
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/can-ml.h>
#include <linux/can/core.h>
#include <linux/can/skb.h>
#include <linux/can/raw.h>
#include <net/sock.h>
#include <net/net_namespace.h>

MODULE_DESCRIPTION("PF_CAN raw protocol");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
MODULE_ALIAS("can-proto-1");

#define RAW_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)

#define MASK_ALL 0

/* A raw socket has a list of can_filters attached to it, each receiving
 * the CAN frames matching that filter.  If the filter list is empty,
 * no CAN frames will be received by the socket.  The default after
 * opening the socket, is to have one filter which receives all frames.
 * The filter list is allocated dynamically with the exception of the
 * list containing only one item.  This common case is optimized by
 * storing the single filter in dfilter, to avoid using dynamic memory.
 */

struct uniqframe {
	const struct sk_buff *skb;
	int skbcnt;
	unsigned int join_rx_count;
};

struct raw_sock {
	struct sock sk;
	struct net_device *dev;
	netdevice_tracker dev_tracker;
	struct list_head notifier;
	int ifindex;
	unsigned int bound:1;
	unsigned int loopback:1;
	unsigned int recv_own_msgs:1;
	unsigned int fd_frames:1;
	unsigned int xl_frames:1;
	unsigned int join_filters:1;
	struct can_raw_vcid_options raw_vcid_opts;
	canid_t tx_vcid_shifted;
	canid_t rx_vcid_shifted;
	canid_t rx_vcid_mask_shifted;
	can_err_mask_t err_mask;
	int count;                 /* number of active filters */
	struct can_filter dfilter; /* default/single filter */
	struct can_filter *filter; /* pointer to filter(s) */
	struct uniqframe __percpu *uniq;
};

static LIST_HEAD(raw_notifier_list);
static DEFINE_SPINLOCK(raw_notifier_lock);
static struct raw_sock *raw_busy_notifier;

/* Return pointer to store the extra msg flags for raw_recvmsg().
 * We use the space of one unsigned int beyond the 'struct sockaddr_can'
 * in skb->cb.
 */
static inline unsigned int *raw_flags(struct sk_buff *skb)
{
	sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
			       sizeof(unsigned int));

	/* return pointer after struct sockaddr_can */
	return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
}

static inline struct raw_sock *raw_sk(const struct sock *sk)
{
	return (struct raw_sock *)sk;
}

static void raw_rcv(struct sk_buff *oskb, void *data)
{
	struct sock *sk = (struct sock *)data;
	struct raw_sock *ro = raw_sk(sk);
	enum skb_drop_reason reason;
	struct sockaddr_can *addr;
	struct sk_buff *skb;
	unsigned int *pflags;

	/* check the received tx sock reference */
	if (!ro->recv_own_msgs && oskb->sk == sk)
		return;

	/* make sure to not pass oversized frames to the socket */
	if (!ro->fd_frames