Subject: Re: [PATCH 3/7] CAN: Add raw protocol

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Tue, 2 Oct 2007 11:30:01 -0300

Em Tue, Oct 02, 2007 at 03:10:09PM +0200, Urs Thuermann escreveu:
> This patch adds the CAN raw protocol.
> 
> Signed-off-by: Oliver Hartkopp <[email-masked]>
> Signed-off-by: Urs Thuermann <[email-masked]>
> 
> ---
>  include/linux/can/raw.h |   31 +
>  net/can/Kconfig         |   11 
>  net/can/Makefile        |    3 
>  net/can/raw.c           |  821 ++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 866 insertions(+)
> 
> Index: net-2.6.24/include/linux/can/raw.h
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.24/include/linux/can/raw.h	2007-10-02 08:33:39.000000000 +0200
> @@ -0,0 +1,31 @@
> +/*
> + * linux/can/raw.h
> + *
> + * Definitions for raw CAN sockets
> + *
> + * Authors: Oliver Hartkopp <[email-masked]>
> + *          Urs Thuermann   <[email-masked]>
> + * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
> + * All rights reserved.
> + *
> + * Send feedback to <[email-masked]>
> + *
> + */
> +
> +#ifndef CAN_RAW_H
> +#define CAN_RAW_H
> +
> +#include <linux/can.h>
> +
> +#define SOL_CAN_RAW (SOL_CAN_BASE + CAN_RAW)
> +
> +/* for socket options affecting the socket (not the global system) */
> +
> +enum {
> +	CAN_RAW_FILTER = 1,	/* set 0 .. n can_filter(s)          */
> +	CAN_RAW_ERR_FILTER,	/* set filter for error frames       */
> +	CAN_RAW_LOOPBACK,	/* local loopback (default:on)       */
> +	CAN_RAW_RECV_OWN_MSGS	/* receive my own msgs (default:off) */
> +};
> +
> +#endif
> Index: net-2.6.24/net/can/Kconfig
> ===================================================================
> --- net-2.6.24.orig/net/can/Kconfig	2007-10-02 06:18:29.000000000 +0200
> +++ net-2.6.24/net/can/Kconfig	2007-10-02 08:35:31.000000000 +0200
> @@ -16,6 +16,17 @@
>  	  If you want CAN support, you should say Y here and also to the
>  	  specific driver for your controller(s) below.
>  
> +config CAN_RAW
> +	tristate "Raw CAN Protocol (raw access with CAN-ID filtering)"
> +	depends on CAN
> +	default N
> +	---help---
> +	  The Raw CAN protocol option offers access to the CAN bus via
> +	  the BSD socket API. You probably want to use the raw socket in
> +	  most cases where no higher level protocol is being used. The raw
> +	  socket has several filter options e.g. ID-Masking / Errorframes.
> +	  To receive/send raw CAN messages, use AF_CAN with protocol CAN_RAW.
> +
>  config CAN_DEBUG_CORE
>  	bool "CAN Core debugging messages"
>  	depends on CAN
> Index: net-2.6.24/net/can/Makefile
> ===================================================================
> --- net-2.6.24.orig/net/can/Makefile	2007-10-02 06:18:29.000000000 +0200
> +++ net-2.6.24/net/can/Makefile	2007-10-02 08:35:31.000000000 +0200
> @@ -4,3 +4,6 @@
>  
>  obj-$(CONFIG_CAN)	+= can.o
>  can-objs		:= af_can.o proc.o
> +
> +obj-$(CONFIG_CAN_RAW)	+= can-raw.o
> +can-raw-objs		:= raw.o
> Index: net-2.6.24/net/can/raw.c
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ net-2.6.24/net/can/raw.c	2007-10-02 08:35:48.000000000 +0200
> @@ -0,0 +1,821 @@
> +/*
> + * 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.
> + *
> + * Send feedback to <[email-masked]>
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/uio.h>
> +#include <linux/poll.h>
> +#include <linux/net.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/raw.h>
> +#include <net/sock.h>
> +#include <net/net_namespace.h>
> +
> +#define IDENT "raw"
> +#define CAN_RAW_VERSION CAN_VERSION
> +static __initdata const char banner[] =
> +	KERN_INFO "can: raw protocol (rev " CAN_RAW_VERSION ")\n";
> +
> +MODULE_DESCRIPTION("PF_CAN raw protocol");
> +MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_AUTHOR("Urs Thuermann <[email-masked]>");
> +
> +#ifdef CONFIG_CAN_DEBUG_CORE
> +static int debug;
> +module_param(debug, int, S_IRUGO);
> +MODULE_PARM_DESC(debug, "debug print mask: 1:debug, 2:frames, 4:skbs");
> +#endif
> +
> +#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 raw_sock {
> +	struct sock sk;
> +	int bound;
> +	int ifindex;
> +	struct notifier_block notifier;
> +	int loopback;
> +	int recv_own_msgs;
> +	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;
> +};
> +
> +static inline struct raw_sock *raw_sk(const struct sock *sk)
> +{
> +	return (struct raw_sock *)sk;
> +}

What if I want to do some kernel module that uses INET raw sockets
(include/net/icmp.h) and CAN raw sockets? Namespace collision, could you
please use can_raw_ for this namespace?

> +static void raw_rcv(struct sk_buff *skb, void *data)
> +{
> +	struct sock *sk = (struct sock *)data;
> +	struct raw_sock *ro = raw_sk(sk);
> +	struct sockaddr_can *addr;
> +	int error;
> +
> +	DBG("received skbuff %p, sk %p\n", skb, sk);
> +	DBG_SKB(skb);
> +
> +	if (!ro->recv_own_msgs) {
> +		/* check the received tx sock reference */
> +		if (skb->sk == sk) {
> +			DBG("trashed own tx msg\n");
> +			kfree_skb(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.
> +	 */
> +
> +	BUILD_BUG_ON(sizeof(skb->cb) < 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;
> +
> +	error = sock_queue_rcv_skb(sk, skb);
> +	if (error < 0) {
> +		DBG("sock_queue_rcv_skb failed: %d\n", error);
> +		DBG("freeing skbuff %p\n", skb);
> +		kfree_skb(skb);
> +	}
> +}
> +
> +static int raw_enable_filters(struct net_device *dev, struct sock *sk,
> +			      struct can_filter *filter,
> +			      int count)
> +{
> +	int err = 0;
> +	int i;
> +
> +	for (i = 0; i < count; i++) {
> +		DBG("filter can_id %08X, can_mask %08X%s, sk %p\n",
> +		    filter[i].can_id, filter[i].can_mask,
> +		    filter[i].can_id & CAN_INV_FILTER ? " (inv)" : "", sk);
> +
> +		err = can_rx_register(dev, filter[i].can_id,
> +				      filter[i].can_mask,
> +				      raw_rcv, sk, IDENT);
> +
> +		if (err) {
> +			/* clean up successfully registered filters */
> +			while (--i >= 0)
> +				can_rx_unregister(dev, filter[i].can_id,
> +						  filter[i].can_mask,
> +						  raw_rcv, sk);
> +			break;
> +		}
> +	}
> +
> +	return err;
> +}
> +
> +static int raw_enable_errfilter(struct net_device *dev, struct sock *sk,
> +				can_err_mask_t err_mask)
> +{
> +	int err = 0;
> +
> +	if (err_mask)
> +		err = can_rx_register(dev, 0, err_mask | CAN_ERR_FLAG,
> +				      raw_rcv, sk, IDENT);
> +
> +	return err;
> +}
> +
> +static void raw_disable_filters(struct net_device *dev, struct sock *sk,
> +			      struct can_filter *filter,
> +			      int count)
> +{
> +	int i;
> +
> +	for (i = 0; i < count; i++) {
> +		DBG("filter can_id %08X, can_mask %08X%s, sk %p\n",
> +		    filter[i].can_id, filter[i].can_mask,
> +		    filter[i].can_id & CAN_INV_FILTER ? " (inv)" : "", sk);
> +
> +		can_rx_unregister(dev, filter[i].can_id, filter[i].can_mask,
> +				  raw_rcv, sk);
> +	}
> +}
> +
> +static inline void raw_disable_errfilter(struct net_device *dev,
> +					 struct sock *sk,
> +					 can_err_mask_t err_mask)
> +
> +{
> +	if (err_mask)
> +		can_rx_unregister(dev, 0, err_mask | CAN_ERR_FLAG,
> +				  raw_rcv, sk);
> +}
> +
> +static inline void raw_disable_allfilters(struct net_device *dev,
> +					  struct sock *sk)
> +{
> +	struct raw_sock *ro = raw_sk(sk);
> +
> +	raw_disable_filters(dev, sk, ro->filter, ro->count);
> +	raw_disable_errfilter(dev, sk, ro->err_mask);
> +}
> +
> +static int raw_enable_allfilters(struct net_device *dev, struct sock *sk)
> +{
> +	struct raw_sock *ro = raw_sk(sk);
> +	int err;
> +
> +	err = raw_enable_filters(dev, sk, ro->filter, ro->count);
> +	if (!err) {
> +		err = raw_enable_errfilter(dev, sk, ro->err_mask);
> +		if (err)
> +			raw_disable_filters(dev, sk, ro->filter, ro->count);
> +	}
> +
> +	return err;
> +}
> +
> +static int raw_notifier(struct notifier_block *nb,
> +			unsigned long msg, void *data)
> +{
> +	struct net_device *dev = (struct net_device *)data;
> +	struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
> +	struct sock *sk = &ro->sk;
> +
> +	DBG("msg %ld for dev %p (%s idx %d) sk %p ro->ifindex %d\n",
> +	    msg, dev, dev->name, dev->ifindex, sk, ro->ifindex);
> +
> +	if (dev->nd_net != &init_net)
> +		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, 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;
> +
> +	/* 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 = raw_sk(sk);
> +
> +	DBG("socket %p, sk %p, refcnt %d\n", sock, sk,
> +	    atomic_read(&sk->sk_refcnt));
> +
> +	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(&init_net, ro->ifindex);
> +			if (dev) {
> +				raw_disable_allfilters(dev, sk);
> +				dev_put(dev);
> +			}
> +		} else
> +			raw_disable_allfilters(NULL, sk);
> +	}
> +
> +	if (ro->count > 1)
> +		kfree(ro->filter);
> +
> +	ro->ifindex = 0;
> +	ro->bound   = 0;
> +	ro->count   = 0;
> +
> +	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;
> +
> +	DBG("socket %p to device %d\n", sock, addr->can_ifindex);
> +
> +	if (len < sizeof(*addr))
> +		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(&init_net, addr->can_ifindex);
> +		if (!dev) {
> +			DBG("could not find device %d\n", addr->can_ifindex);
> +			err = -ENODEV;
> +			goto out;
> +		}
> +		if (dev->type != ARPHRD_CAN) {
> +			DBG("device %d no CAN device\n", addr->can_ifindex);
> +			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(dev, sk);
> +		dev_put(dev);
> +
> +	} else {
> +		ifindex = 0;
> +
> +		/* filters set by default/setsockopt */
> +		err = raw_enable_allfilters(NULL, sk);
> +	}
> +
> +	if (!err) {
> +		if (ro->bound) {
> +			/* unregister old filters */
> +			if (ro->ifindex) {
> +				struct net_device *dev;
> +
> +				dev = dev_get_by_index(&init_net, ro->ifindex);
> +				if (dev) {
> +					raw_disable_allfilters(dev, sk);
> +					dev_put(dev);
> +				}
> +			} else
> +				raw_disable_allfilters(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 *len, 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;
> +
> +	addr->can_family  = AF_CAN;
> +	addr->can_ifindex = ro->ifindex;
> +
> +	*len = sizeof(*addr);
> +
> +	return 0;
> +}
> +
> +static unsigned int raw_poll(struct file *file, struct socket *sock,
> +			     poll_table *wait)
> +{
> +	unsigned int mask = 0;
> +
> +	DBG("socket %p\n", sock);
> +
> +	mask = datagram_poll(file, sock, wait);
> +	return mask;

What is the value of 'mask' here? Leftover from debugging?

> +}
> +
> +static int raw_setsockopt(struct socket *sock, int level, int optname,
> +			  char __user *optval, 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;
> +	if (optlen < 0)
> +		return -EINVAL;
> +
> +	switch (optname) {
> +
> +	case CAN_RAW_FILTER:
> +		if (optlen % sizeof(struct can_filter) != 0)
> +			return -EINVAL;
> +
> +		count = optlen / sizeof(struct can_filter);
> +
> +		if (count > 1) {
> +			/* filter does not fit into dfilter => alloc space */
> +			filter = kmalloc(optlen, GFP_KERNEL);
> +			if (!filter)
> +				return -ENOMEM;
> +
> +			err = copy_from_user(filter, optval, optlen);
> +			if (err) {
> +				kfree(filter);
> +				return err;
> +			}
> +		} else if (count == 1) {
> +			err = copy_from_user(&sfilter, optval, optlen);
> +			if (err)
> +				return err;
> +		}
> +
> +		lock_sock(sk);
> +
> +		if (ro->bound && ro->ifindex)
> +			dev = dev_get_by_index(&init_net, ro->ifindex);

dev_get_by_index can fail, are you sure that raw_enable_filters can cope
with this possibility?

> +		if (ro->bound) {
> +			/* (try to) register the new filters */
> +			if (count == 1)
> +				err = raw_enable_filters(dev, sk, &sfilter, 1);
> +			else
> +				err = raw_enable_filters(dev, sk, filter,
> +							 count);
> +			if (err) {
> +				if (count > 1)
> +					kfree(filter);
> +
> +				goto out_fil;
> +			}
> +
> +			/* remove old filter registrations */
> +			raw_disable_filters(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;
> +
> +		err = copy_from_user(&err_mask, optval, optlen);
> +		if (err)
> +			return err;
> +
> +		err_mask &= CAN_ERR_MASK;
> +
> +		lock_sock(sk);
> +
> +		if (ro->bound && ro->ifindex)
> +			dev = dev_get_by_index(&init_net, ro->ifindex);
> +
> +		/* remove current error mask */
> +		if (ro->bound) {
> +			/* (try to) register the new err_mask */
> +			err = raw_enable_errfilter(dev, sk, err_mask);
> +
> +			if (err)
> +				goto out_err;
> +
> +			/* remove old err_mask registration */
> +			raw_disable_errfilter(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;
> +
> +		err = copy_from_user(&ro->loopback, optval, optlen);
> +
> +		break;
> +
> +	case CAN_RAW_RECV_OWN_MSGS:
> +		if (optlen != sizeof(ro->recv_own_msgs))
> +			return -EINVAL;
> +
> +		err = copy_from_user(&ro->recv_own_msgs, optval, optlen);
> +
> +		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;
> +			err = copy_to_user(optval, ro->filter, len);
> +		} 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;
> +
> +	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 kiocb *iocb, 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;
> +
> +	DBG("socket %p, sk %p\n", sock, sk);
> +
> +	if (msg->msg_name) {
> +		struct sockaddr_can *addr =
> +			(struct sockaddr_can *)msg->msg_name;
> +
> +		if (addr->can_family != AF_CAN)
> +			return -EINVAL;
> +
> +		ifindex = addr->can_ifindex;
> +	} else
> +		ifindex = ro->ifindex;
> +
> +	dev = dev_get_by_index(&init_net, ifindex);
> +	if (!dev) {
> +		DBG("device %d not found\n", ifindex);
> +		return -ENXIO;
> +	}
> +
> +	skb = alloc_skb(size, GFP_KERNEL);
> +	if (!skb) {
> +		dev_put(dev);
> +		return -ENOMEM;
> +	}
> +
> +	err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
> +	if (err < 0) {
> +		kfree_skb(skb);
> +		dev_put(dev);
> +		return err;
> +	}
> +	skb->dev = dev;
> +	skb->sk  = sk;
> +
> +	DBG("sending skbuff to interface %d\n", ifindex);
> +	DBG_SKB(skb);
> +
> +	err = can_send(skb, ro->loopback);
> +
> +	dev_put(dev);
> +
> +	if (err)
> +		return err;
> +
> +	return size;
> +}
> +
> +static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
> +		       struct msghdr *msg, size_t size, int flags)
> +{
> +	struct sock *sk = sock->sk;
> +	struct sk_buff *skb;
> +	int error = 0;
> +	int noblock;
> +
> +	DBG("socket %p, sk %p\n", sock, sk);
> +
> +	noblock =  flags & MSG_DONTWAIT;
> +	flags   &= ~MSG_DONTWAIT;
> +
> +	skb = skb_recv_datagram(sk, flags, noblock, &error);
> +	if (!skb)
> +		return error;
> +
> +	DBG("delivering skbuff %p\n", skb);
> +	DBG_SKB(skb);
> +
> +	if (size < skb->len)
> +		msg->msg_flags |= MSG_TRUNC;
> +	else
> +		size = skb->len;
> +
> +	error = memcpy_toiovec(msg->msg_iov, skb->data, size);
> +	if (error < 0) {
> +		skb_free_datagram(sk, skb);
> +		return error;
> +	}
> +
> +	sock_recv_timestamp(msg, sk, skb);
> +
> +	if (msg->msg_name) {
> +		msg->msg_namelen = sizeof(struct sockaddr_can);
> +		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
> +	}
> +
> +	DBG("freeing sock %p, skbuff %p\n", sk, skb);
> +	skb_free_datagram(sk, skb);
> +
> +	return size;
> +}
> +
> +static struct proto_ops raw_ops __read_mostly = {
> +	.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          = raw_poll,
> +	.ioctl         = NULL,		/* use can_ioctl() from af_can.c */
> +	.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 struct can_proto raw_can_proto __read_mostly = {
> +	.type       = SOCK_RAW,
> +	.protocol   = CAN_RAW,
> +	.capability = -1,
> +	.ops        = &raw_ops,
> +	.prot       = &raw_proto,
> +};
> +
> +static __init int raw_module_init(void)
> +{
> +	int err;
> +
> +	printk(banner);
> +
> +	err = can_proto_register(&raw_can_proto);
> +	if (err < 0)
> +		printk(KERN_ERR "can: registration of raw protocol failed\n");
> +
> +	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);
> 
> --