// 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/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 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 {

  	int skbcnt;

  	const struct sk_buff *skb;

  	unsigned int join_rx_count;

  };

  struct raw_sock {
  	struct sock sk;
  	int bound;
  	int ifindex;
  	struct notifier_block notifier;
  	int loopback;
  	int recv_own_msgs;

  	int fd_frames;

  	int join_filters;

  	int count;                 /* number of active filters */
  	struct can_filter dfilter; /* default/single filter */
  	struct can_filter *filter; /* pointer to filter(s) */
  	can_err_mask_t err_mask;

  	struct uniqframe __percpu *uniq;

  };

  /* 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);
  	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;

  	/* do not pass non-CAN2.0 frames to a legacy socket */
  	if (!ro->fd_frames && oskb->len != CAN_MTU)
  		return;

  	/* eliminate multiple filter matches for the same skb */
  	if (this_cpu_ptr(ro->uniq)->skb == oskb &&

  	    this_cpu_ptr(ro->uniq)->skbcnt == can_skb_prv(oskb)->skbcnt) {

  		if (ro->join_filters) {
  			this_cpu_inc(ro->uniq->join_rx_count);
  			/* drop frame until all enabled filters matched */
  			if (this_cpu_ptr(ro->uniq)->join_rx_count < ro->count)
  				return;
  		} else {
  			return;
  		}

  	} else {
  		this_cpu_ptr(ro->uniq)->skb = oskb;

  		this_cpu_ptr(ro->uniq)->skbcnt = can_skb_prv(oskb)->skbcnt;

  		this_cpu_ptr(ro->uniq)->join_rx_count = 1;
  		/* drop first frame to check all enabled filters? */
  		if (ro->join_filters && ro->count > 1)
  			return;

  	}

  	/* clone the given skb to be able to enqueue it into the rcv queue */

  	skb = skb_clone(oskb, GFP_ATOMIC);

  	if (!skb)
  		return;

  	/* Put the datagram to the queue so that raw_recvmsg() can get
  	 * it from there. We need to pass the interface index to
  	 * raw_recvmsg(). We pass a whole struct sockaddr_can in
  	 * skb->cb containing the interface index.

  	 */

  	sock_skb_cb_check_size(sizeof(struct sockaddr_can));

  	addr = (struct sockaddr_can *)skb->cb;
  	memset(addr, 0, sizeof(*addr));

  	addr->can_family = AF_CAN;

  	addr->can_ifindex = skb->dev->ifindex;

  	/* add CAN specific message flags for raw_recvmsg() */
  	pflags = raw_flags(skb);
  	*pflags = 0;
  	if (oskb->sk)
  		*pflags |= MSG_DONTROUTE;
  	if (oskb->sk == sk)
  		*pflags |= MSG_CONFIRM;

  	if (sock_queue_rcv_skb(sk, skb) < 0)

  		kfree_skb(skb);
  }

  static int raw_enable_filters(struct net *net, struct net_device *dev,
  			      struct sock *sk, struct can_filter *filter,
  			      int count)

  {
  	int err = 0;
  	int i;
  
  	for (i = 0; i < count; i++) {

  		err = can_rx_register(net, dev, filter[i].can_id,

  				      filter[i].can_mask,

  				      raw_rcv, sk, "raw", sk);

  		if (err) {
  			/* clean up successfully registered filters */
  			while (--i >= 0)

  				can_rx_unregister(net, dev, filter[i].can_id,

  						  filter[i].can_mask,
  						  raw_rcv, sk);
  			break;
  		}
  	}
  
  	return err;
  }

  static int raw_enable_errfilter(struct net *net, struct net_device *dev,
  				struct sock *sk, can_err_mask_t err_mask)

  {
  	int err = 0;
  
  	if (err_mask)

  		err = can_rx_register(net, dev, 0, err_mask | CAN_ERR_FLAG,

  				      raw_rcv, sk, "raw", sk);

  
  	return err;
  }

  static void raw_disable_filters(struct net *net, struct net_device *dev,
  				struct sock *sk, struct can_filter *filter,
  				int count)

  {
  	int i;
  
  	for (i = 0; i < count; i++)

  		can_rx_unregister(net, dev, filter[i].can_id,
  				  filter[i].can_mask, raw_rcv, sk);

  }

  static inline void raw_disable_errfilter(struct net *net,
  					 struct net_device *dev,

  					 struct sock *sk,
  					 can_err_mask_t err_mask)
  
  {
  	if (err_mask)

  		can_rx_unregister(net, dev, 0, err_mask | CAN_ERR_FLAG,

  				  raw_rcv, sk);
  }

  static inline void raw_disable_allfilters(struct net *net,
  					  struct net_device *dev,

  					  struct sock *sk)
  {
  	struct raw_sock *ro = raw_sk(sk);

  	raw_disable_filters(net, dev, sk, ro->filter, ro->count);
  	raw_disable_errfilter(net, dev, sk, ro->err_mask);

  }

  static int raw_enable_allfilters(struct net *net, struct net_device *dev,
  				 struct sock *sk)

  {
  	struct raw_sock *ro = raw_sk(sk);
  	int err;

  	err = raw_enable_filters(net, dev, sk, ro->filter, ro->count);

  	if (!err) {

  		err = raw_enable_errfilter(net, dev, sk, ro->err_mask);

  		if (err)

  			raw_disable_filters(net, dev, sk, ro->filter,
  					    ro->count);

  	}
  
  	return err;
  }
  
  static int raw_notifier(struct notifier_block *nb,

  			unsigned long msg, void *ptr)

  {

  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

  	struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
  	struct sock *sk = &ro->sk;

  	if (!net_eq(dev_net(dev), sock_net(sk)))

  		return NOTIFY_DONE;
  
  	if (dev->type != ARPHRD_CAN)
  		return NOTIFY_DONE;
  
  	if (ro->ifindex != dev->ifindex)
  		return NOTIFY_DONE;
  
  	switch (msg) {

  	case NETDEV_UNREGISTER:
  		lock_sock(sk);
  		/* remove current filters & unregister */
  		if (ro->bound)

  			raw_disable_allfilters(dev_net(dev), dev, sk);

  
  		if (ro->count > 1)
  			kfree(ro->filter);
  
  		ro->ifindex = 0;

  		ro->bound = 0;
  		ro->count = 0;

  		release_sock(sk);
  
  		sk->sk_err = ENODEV;
  		if (!sock_flag(sk, SOCK_DEAD))
  			sk->sk_error_report(sk);
  		break;
  
  	case NETDEV_DOWN:
  		sk->sk_err = ENETDOWN;
  		if (!sock_flag(sk, SOCK_DEAD))
  			sk->sk_error_report(sk);
  		break;
  	}
  
  	return NOTIFY_DONE;
  }
  
  static int raw_init(struct sock *sk)
  {
  	struct raw_sock *ro = raw_sk(sk);
  
  	ro->bound            = 0;
  	ro->ifindex          = 0;
  
  	/* set default filter to single entry dfilter */
  	ro->dfilter.can_id   = 0;
  	ro->dfilter.can_mask = MASK_ALL;
  	ro->filter           = &ro->dfilter;
  	ro->count            = 1;
  
  	/* set default loopback behaviour */
  	ro->loopback         = 1;
  	ro->recv_own_msgs    = 0;

  	ro->fd_frames        = 0;

  	ro->join_filters     = 0;

  	/* alloc_percpu provides zero'ed memory */
  	ro->uniq = alloc_percpu(struct uniqframe);
  	if (unlikely(!ro->uniq))
  		return -ENOMEM;

  	/* set notifier */
  	ro->notifier.notifier_call = raw_notifier;
  
  	register_netdevice_notifier(&ro->notifier);
  
  	return 0;
  }
  
  static int raw_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;

  	struct raw_sock *ro;
  
  	if (!sk)
  		return 0;
  
  	ro = raw_sk(sk);

  
  	unregister_netdevice_notifier(&ro->notifier);
  
  	lock_sock(sk);
  
  	/* remove current filters & unregister */
  	if (ro->bound) {
  		if (ro->ifindex) {
  			struct net_device *dev;

  			dev = dev_get_by_index(sock_net(sk), ro->ifindex);

  			if (dev) {

  				raw_disable_allfilters(dev_net(dev), dev, sk);

  				dev_put(dev);
  			}

  		} else {

  			raw_disable_allfilters(sock_net(sk), NULL, sk);

  		}

  	}
  
  	if (ro->count > 1)
  		kfree(ro->filter);
  
  	ro->ifindex = 0;

  	ro->bound = 0;
  	ro->count = 0;

  	free_percpu(ro->uniq);

  	sock_orphan(sk);
  	sock->sk = NULL;

  	release_sock(sk);
  	sock_put(sk);
  
  	return 0;
  }
  
  static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
  {
  	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
  	struct sock *sk = sock->sk;
  	struct raw_sock *ro = raw_sk(sk);
  	int ifindex;
  	int err = 0;
  	int notify_enetdown = 0;

  	if (len < CAN_REQUIRED_SIZE(*addr, can_ifindex))

  		return -EINVAL;

  	if (addr->can_family != AF_CAN)
  		return -EINVAL;

  
  	lock_sock(sk);
  
  	if (ro->bound && addr->can_ifindex == ro->ifindex)
  		goto out;
  
  	if (addr->can_ifindex) {
  		struct net_device *dev;

  		dev = dev_get_by_index(sock_net(sk), addr->can_ifindex);

  		if (!dev) {
  			err = -ENODEV;
  			goto out;
  		}
  		if (dev->type != ARPHRD_CAN) {
  			dev_put(dev);
  			err = -ENODEV;
  			goto out;
  		}
  		if (!(dev->flags & IFF_UP))
  			notify_enetdown = 1;
  
  		ifindex = dev->ifindex;
  
  		/* filters set by default/setsockopt */

  		err = raw_enable_allfilters(sock_net(sk), dev, sk);

  		dev_put(dev);

  	} else {
  		ifindex = 0;
  
  		/* filters set by default/setsockopt */

  		err = raw_enable_allfilters(sock_net(sk), NULL, sk);

  	}
  
  	if (!err) {
  		if (ro->bound) {
  			/* unregister old filters */
  			if (ro->ifindex) {
  				struct net_device *dev;

  				dev = dev_get_by_index(sock_net(sk),
  						       ro->ifindex);

  				if (dev) {

  					raw_disable_allfilters(dev_net(dev),
  							       dev, sk);

  					dev_put(dev);
  				}

  			} else {

  				raw_disable_allfilters(sock_net(sk), NULL, sk);

  			}

  		}
  		ro->ifindex = ifindex;
  		ro->bound = 1;
  	}
  
   out:
  	release_sock(sk);
  
  	if (notify_enetdown) {
  		sk->sk_err = ENETDOWN;
  		if (!sock_flag(sk, SOCK_DEAD))
  			sk->sk_error_report(sk);
  	}
  
  	return err;
  }
  
  static int raw_getname(struct socket *sock, struct sockaddr *uaddr,

  		       int peer)

  {
  	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
  	struct sock *sk = sock->sk;
  	struct raw_sock *ro = raw_sk(sk);
  
  	if (peer)
  		return -EOPNOTSUPP;

  	memset(addr, 0, sizeof(*addr));

  	addr->can_family  = AF_CAN;
  	addr->can_ifindex = ro->ifindex;

  	return sizeof(*addr);

  }
  
  static int raw_setsockopt(struct socket *sock, int level, int optname,

  			  sockptr_t optval, unsigned int optlen)

  {
  	struct sock *sk = sock->sk;
  	struct raw_sock *ro = raw_sk(sk);
  	struct can_filter *filter = NULL;  /* dyn. alloc'ed filters */
  	struct can_filter sfilter;         /* single filter */
  	struct net_device *dev = NULL;
  	can_err_mask_t err_mask = 0;
  	int count = 0;
  	int err = 0;
  
  	if (level != SOL_CAN_RAW)
  		return -EINVAL;

  
  	switch (optname) {

  	case CAN_RAW_FILTER:
  		if (optlen % sizeof(struct can_filter) != 0)
  			return -EINVAL;

  		if (optlen > CAN_RAW_FILTER_MAX * sizeof(struct can_filter))
  			return -EINVAL;

  		count = optlen / sizeof(struct can_filter);
  
  		if (count > 1) {
  			/* filter does not fit into dfilter => alloc space */

  			filter = memdup_sockptr(optval, optlen);

  			if (IS_ERR(filter))
  				return PTR_ERR(filter);

  		} else if (count == 1) {

  			if (copy_from_sockptr(&sfilter, optval, sizeof(sfilter)))

  				return -EFAULT;

  		}
  
  		lock_sock(sk);
  
  		if (ro->bound && ro->ifindex)

  			dev = dev_get_by_index(sock_net(sk), ro->ifindex);

  
  		if (ro->bound) {
  			/* (try to) register the new filters */
  			if (count == 1)

  				err = raw_enable_filters(sock_net(sk), dev, sk,
  							 &sfilter, 1);

  			else

  				err = raw_enable_filters(sock_net(sk), dev, sk,
  							 filter, count);

  			if (err) {
  				if (count > 1)
  					kfree(filter);

  				goto out_fil;
  			}
  
  			/* remove old filter registrations */

  			raw_disable_filters(sock_net(sk), dev, sk, ro->filter,
  					    ro->count);

  		}
  
  		/* remove old filter space */
  		if (ro->count > 1)
  			kfree(ro->filter);
  
  		/* link new filters to the socket */
  		if (count == 1) {
  			/* copy filter data for single filter */
  			ro->dfilter = sfilter;
  			filter = &ro->dfilter;
  		}
  		ro->filter = filter;
  		ro->count  = count;
  
   out_fil:
  		if (dev)
  			dev_put(dev);
  
  		release_sock(sk);
  
  		break;
  
  	case CAN_RAW_ERR_FILTER:
  		if (optlen != sizeof(err_mask))
  			return -EINVAL;

  		if (copy_from_sockptr(&err_mask, optval, optlen))

  			return -EFAULT;

  
  		err_mask &= CAN_ERR_MASK;
  
  		lock_sock(sk);
  
  		if (ro->bound && ro->ifindex)

  			dev = dev_get_by_index(sock_net(sk), ro->ifindex);

  
  		/* remove current error mask */
  		if (ro->bound) {
  			/* (try to) register the new err_mask */

  			err = raw_enable_errfilter(sock_net(sk), dev, sk,
  						   err_mask);

  
  			if (err)
  				goto out_err;
  
  			/* remove old err_mask registration */

  			raw_disable_errfilter(sock_net(sk), dev, sk,
  					      ro->err_mask);

  		}
  
  		/* link new err_mask to the socket */
  		ro->err_mask = err_mask;
  
   out_err:
  		if (dev)
  			dev_put(dev);
  
  		release_sock(sk);
  
  		break;
  
  	case CAN_RAW_LOOPBACK:
  		if (optlen != sizeof(ro->loopback))
  			return -EINVAL;

  		if (copy_from_sockptr(&ro->loopback, optval, optlen))

  			return -EFAULT;

  
  		break;
  
  	case CAN_RAW_RECV_OWN_MSGS:
  		if (optlen != sizeof(ro->recv_own_msgs))
  			return -EINVAL;

  		if (copy_from_sockptr(&ro->recv_own_msgs, optval, optlen))

  			return -EFAULT;

  
  		break;

  	case CAN_RAW_FD_FRAMES:
  		if (optlen != sizeof(ro->fd_frames))
  			return -EINVAL;

  		if (copy_from_sockptr(&ro->fd_frames, optval, optlen))

  			return -EFAULT;
  
  		break;

  	case CAN_RAW_JOIN_FILTERS:
  		if (optlen != sizeof(ro->join_filters))
  			return -EINVAL;

  		if (copy_from_sockptr(&ro->join_filters, optval, optlen))

  			return -EFAULT;
  
  		break;

  	default:
  		return -ENOPROTOOPT;
  	}
  	return err;
  }
  
  static int raw_getsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, int __user *optlen)
  {
  	struct sock *sk = sock->sk;
  	struct raw_sock *ro = raw_sk(sk);
  	int len;
  	void *val;
  	int err = 0;
  
  	if (level != SOL_CAN_RAW)
  		return -EINVAL;
  	if (get_user(len, optlen))
  		return -EFAULT;
  	if (len < 0)
  		return -EINVAL;
  
  	switch (optname) {

  	case CAN_RAW_FILTER:
  		lock_sock(sk);
  		if (ro->count > 0) {
  			int fsize = ro->count * sizeof(struct can_filter);

  			if (len > fsize)
  				len = fsize;

  			if (copy_to_user(optval, ro->filter, len))
  				err = -EFAULT;

  		} else {

  			len = 0;

  		}

  		release_sock(sk);
  
  		if (!err)
  			err = put_user(len, optlen);
  		return err;
  
  	case CAN_RAW_ERR_FILTER:
  		if (len > sizeof(can_err_mask_t))
  			len = sizeof(can_err_mask_t);
  		val = &ro->err_mask;
  		break;
  
  	case CAN_RAW_LOOPBACK:
  		if (len > sizeof(int))
  			len = sizeof(int);
  		val = &ro->loopback;
  		break;
  
  	case CAN_RAW_RECV_OWN_MSGS:
  		if (len > sizeof(int))
  			len = sizeof(int);
  		val = &ro->recv_own_msgs;
  		break;

  	case CAN_RAW_FD_FRAMES:
  		if (len > sizeof(int))
  			len = sizeof(int);
  		val = &ro->fd_frames;
  		break;

  	case CAN_RAW_JOIN_FILTERS:
  		if (len > sizeof(int))
  			len = sizeof(int);
  		val = &ro->join_filters;
  		break;

  	default:
  		return -ENOPROTOOPT;
  	}
  
  	if (put_user(len, optlen))
  		return -EFAULT;
  	if (copy_to_user(optval, val, len))
  		return -EFAULT;
  	return 0;
  }

  static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)

  {
  	struct sock *sk = sock->sk;
  	struct raw_sock *ro = raw_sk(sk);
  	struct sk_buff *skb;
  	struct net_device *dev;
  	int ifindex;
  	int err;
  
  	if (msg->msg_name) {

  		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);

  		if (msg->msg_namelen < CAN_REQUIRED_SIZE(*addr, can_ifindex))

  			return -EINVAL;

  		if (addr->can_family != AF_CAN)
  			return -EINVAL;
  
  		ifindex = addr->can_ifindex;

  	} else {

  		ifindex = ro->ifindex;

  	}

  	dev = dev_get_by_index(sock_net(sk), ifindex);
  	if (!dev)
  		return -ENXIO;
  
  	err = -EINVAL;
  	if (ro->fd_frames && dev->mtu == CANFD_MTU) {

  		if (unlikely(size != CANFD_MTU && size != CAN_MTU))

  			goto put_dev;

  	} else {
  		if (unlikely(size != CAN_MTU))

  			goto put_dev;

  	}

  	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
  				  msg->msg_flags & MSG_DONTWAIT, &err);

  	if (!skb)
  		goto put_dev;

  	can_skb_reserve(skb);
  	can_skb_prv(skb)->ifindex = dev->ifindex;

  	can_skb_prv(skb)->skbcnt = 0;

  	err = memcpy_from_msg(skb_put(skb, size), msg, size);

  	if (err < 0)
  		goto free_skb;

  	skb_setup_tx_timestamp(skb, sk->sk_tsflags);

  	skb->dev = dev;

  	skb->sk = sk;

  	skb->priority = sk->sk_priority;

  
  	err = can_send(skb, ro->loopback);
  
  	dev_put(dev);
  
  	if (err)

  		goto send_failed;

  
  	return size;

  
  free_skb:
  	kfree_skb(skb);
  put_dev:
  	dev_put(dev);
  send_failed:
  	return err;

  }

  static int raw_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
  		       int flags)

  {
  	struct sock *sk = sock->sk;
  	struct sk_buff *skb;

  	int err = 0;

  	int noblock;

  	noblock = flags & MSG_DONTWAIT;
  	flags &= ~MSG_DONTWAIT;

  	if (flags & MSG_ERRQUEUE)
  		return sock_recv_errqueue(sk, msg, size,
  					  SOL_CAN_RAW, SCM_CAN_RAW_ERRQUEUE);

  	skb = skb_recv_datagram(sk, flags, noblock, &err);

  	if (!skb)

  		return err;

  	if (size < skb->len)

  		msg->msg_flags |= MSG_TRUNC;
  	else

  		size = skb->len;

  	err = memcpy_to_msg(msg, skb->data, size);

  	if (err < 0) {

  		skb_free_datagram(sk, skb);

  		return err;

  	}

  	sock_recv_ts_and_drops(msg, sk, skb);

  
  	if (msg->msg_name) {

  		__sockaddr_check_size(sizeof(struct sockaddr_can));

  		msg->msg_namelen = sizeof(struct sockaddr_can);
  		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
  	}

  	/* assign the flags that have been recorded in raw_rcv() */
  	msg->msg_flags |= *(raw_flags(skb));

  	skb_free_datagram(sk, skb);
  
  	return size;
  }

  static int raw_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
  				unsigned long arg)

  {
  	/* no ioctls for socket layer -> hand it down to NIC layer */
  	return -ENOIOCTLCMD;
  }

  static const struct proto_ops raw_ops = {

  	.family        = PF_CAN,
  	.release       = raw_release,
  	.bind          = raw_bind,
  	.connect       = sock_no_connect,
  	.socketpair    = sock_no_socketpair,
  	.accept        = sock_no_accept,
  	.getname       = raw_getname,

  	.poll          = datagram_poll,

  	.ioctl         = raw_sock_no_ioctlcmd,

  	.gettstamp     = sock_gettstamp,

  	.listen        = sock_no_listen,
  	.shutdown      = sock_no_shutdown,
  	.setsockopt    = raw_setsockopt,
  	.getsockopt    = raw_getsockopt,
  	.sendmsg       = raw_sendmsg,
  	.recvmsg       = raw_recvmsg,
  	.mmap          = sock_no_mmap,
  	.sendpage      = sock_no_sendpage,
  };
  
  static struct proto raw_proto __read_mostly = {
  	.name       = "CAN_RAW",
  	.owner      = THIS_MODULE,
  	.obj_size   = sizeof(struct raw_sock),
  	.init       = raw_init,
  };

  static const struct can_proto raw_can_proto = {

  	.type       = SOCK_RAW,
  	.protocol   = CAN_RAW,

  	.ops        = &raw_ops,
  	.prot       = &raw_proto,
  };
  
  static __init int raw_module_init(void)
  {
  	int err;

  	pr_info("can: raw protocol
  ");

  
  	err = can_proto_register(&raw_can_proto);
  	if (err < 0)

  		pr_err("can: registration of raw protocol failed
  ");

  
  	return err;
  }
  
  static __exit void raw_module_exit(void)
  {
  	can_proto_unregister(&raw_can_proto);
  }
  
  module_init(raw_module_init);
  module_exit(raw_module_exit);