// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/* af_can.c - Protocol family CAN core module
* (used by different CAN protocol modules)
*
* Copyright (c) 2002-2017 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/stddef.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/uaccess.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_ether.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/can-ml.h>
#include <linux/ratelimit.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include "af_can.h"
MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <[email protected]>, "
"Oliver Hartkopp <[email protected]>");
MODULE_ALIAS_NETPROTO(PF_CAN);
static int stats_timer __read_mostly = 1;
module_param(stats_timer, int, 0444);
MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
static struct kmem_cache *rcv_cache __read_mostly;
/* table of registered CAN protocols */
static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
static DEFINE_MUTEX(proto_tab_lock);
static atomic_t skbcounter = ATOMIC_INIT(0);
/* af_can socket functions */
void can_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_error_queue);
}
EXPORT_SYMBOL(can_sock_destruct);
static const struct can_proto *can_get_proto(int protocol)
{
const struct can_proto *cp;
rcu_read_lock();
cp = rcu_dereference(proto_tab[protocol]);
if (cp && !try_module_get(cp->prot->owner))
cp = NULL;
rcu_read_unlock();
return cp;
}
static inline void can_put_proto(const struct can_proto *cp)
{
module_put(cp->prot->owner);
}
static int can_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk;
const struct can_proto *cp;
int err = 0;
sock->state = SS_UNCONNECTED;
if (protocol < 0 || protocol >= CAN_NPROTO)
return -EINVAL;
cp = can_get_proto(protocol);
#ifdef CONFIG_MODULES
if (!cp) {
/* try to load protocol module if kernel is modular */
err = request_module("can-proto-%d", protocol);
/* In case of error we only print a message but don't
* return the error code immediately. Below we will
* return -EPROTONOSUPPORT
*/
if (err)
pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n",
protocol);
cp = can_get_proto(protocol);
}
#endif
/* check for available protocol and correct usage */
if (!cp)
return -EPROTONOSUPPORT;
if (cp->type != sock->type) {
err = -EPROTOTYPE;
goto errout;
}
sock->ops = cp->ops;
sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
if (!sk) {
err = -ENOMEM;
goto errout;
}
sock_init_data(sock, sk);
sk->sk_destruct = can_sock_destruct;
if (sk->sk_prot->init)
err = sk->sk_prot->init(sk);
if (err) {
/* release sk on errors */
sock_orphan(sk);
sock_put(sk);
}
errout:
can_put_proto(cp);
return err;
}
/* af_can tx path */
/**
* can_send - transmit a CAN frame (optional with local loopback)
* @skb: pointer to socket buffer with CAN frame in data section
* @loop: loopback for listeners on local CAN sockets (recommended default!)
*
* Due to the loopback this routine must not be called from hardirq context.
*
* Return:
* 0 on success
* -ENETDOWN when the selected interface is down
* -ENOBUFS on full driver queue (see net_xmit_errno())
* -ENOMEM when local loopback failed at calling skb_clone()
* -EPERM when trying to send on a non-CAN interface
* -EMSGSIZE CAN frame size is bigger than CAN interface MTU
* -EINVAL when the skb->data does not contain a valid CAN frame
*/
int can_send(struct sk_buff *skb, int loop)
{
struct sk_buff *newskb = NULL;
struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
int err = -EINVAL;
if (can_is_canxl_skb(skb)) {
skb->protocol = htons(ETH_P_CANXL);
} else if (can_is_can_skb(skb)) {
skb->protocol = htons(ETH_P_CAN);
} else if (can_is_canfd_skb(skb)) {
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
skb->protocol = htons(ETH_P_CANFD);
/* set CAN FD flag for CAN FD frames by default */
cfd->flags |= CANFD_FDF;
} else {
goto inval_skb;
}
/* Make sure the CAN frame can pass the selected CAN netdevice. */
if (unlikely(skb->len > skb->dev->mtu)) {
err = -EMSGSIZE;
goto inval_skb;
}
if (unlikely(skb->dev->type != ARPHRD_CAN)) {
err = -EPERM;
goto inval_skb;
}
if (unlikely(!(skb->dev->flags & IFF_UP))) {
err = -ENETDOWN;
goto inval_skb;
}
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
if (loop) {
/* local loopback of sent CAN frames */
/* indication for the CAN driver: do loopback */
skb->pkt_type = PACKET_LOOPBACK;
/* The reference to the originating sock may be required
* by the receiving socket to check whether the frame is
* its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
* Therefore we have to ensure that skb->sk remains the
* reference to the originating sock by restoring skb->sk
* after each skb_clone() or skb_orphan() usage.
*/
if (!(skb->dev->flags & IFF_ECHO)) {
/* If the interface is not capable to do loopback
* itself, we do it here.
*/
newskb = skb_clone(skb, GFP_ATOMIC);
if (!newskb) {
kfree_skb(skb);
return -ENOMEM;
}
can_skb_set_owner(newskb, skb->sk);
newskb->ip_summed = CHECKSUM_UNNECESSARY;
newskb->pkt_type = PACKET_BROADCAST;
}
} else {
/* indication for the CAN driver: no loopback required */
skb->pkt_type = PACKET_HOST;
}
/* send to netdevice */
err = dev_queue_xmit(skb);
if (err > 0)
err = net_xmit_errno(err);
if (err) {
kfree_skb(newskb);
return err;
}
if (newskb)
netif_rx(newskb);
/* update statistics */
pkg_stats->tx_frames++;
pkg_stats->tx_frames_delta++;
return 0;
inval_skb:
kfree_skb(skb);
return err;
}
EXPORT_SYMBOL(can_send);
/* af_can rx path */
static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
struct net_device *dev)
{
if (dev) {
struct can_ml_priv *can_ml = can_get_ml_priv(dev);
return &can_ml->dev_rcv_lists;
} else {
return net->can.rx_alldev_list;
}
}
/**
* effhash - hash function for 29 bit CAN identifier reduction
* @can_id: 29 bit CAN identifier
*
* Description:
* To reduce the linear traversal in one linked list of _single_ EFF CAN
* frame subscriptions the 29 bit identifier is mapped to 10 bits.
* (see CAN_EFF_RCV_HASH_BITS definition)
*
* Return:
* Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
*/
static unsigned int effhash(canid_t can_id)
{
unsigned int hash;
hash = can_id;
hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
}
/**
* can_rcv_list_find - determine optimal filterlist inside device filter struct
* @can_id: pointer to CAN identifier of a given can_filter
* @mask: pointer to CAN mask of a given can_filter
* @dev_rcv_lists: pointer to the device filter struct
*
* Description:
* Returns the optimal filterlist to reduce the filter handling in the
* receive path. This function is called by service functions that need
* to register or unregister a can_filter in the filter lists.
*
* A filter matches in general, when
*
* <received_can_id> & mask == can_id & mask
*
* so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
* relevant bits for the filter.
*
* The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
* filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
* frames there is a special filterlist and a special rx path filter handling.
*
* Return:
* Pointer to optimal filterlist for the given can_id/mask pair.
* Consistency checked mask.
* Reduced can_id to have a preprocessed filter compare value.
*/
static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
struct can_dev_rcv_lists *dev_rcv_lists)
{
canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
/* filter for error message frames in extra filterlist */
if (*mask & CAN_ERR_FLAG) {
/* clear CAN_ERR_FLAG in filter entry */
*mask &= CAN_ERR_MASK;
return &dev_rcv_lists->rx[RX_ERR];
}
/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
/* ensure valid values in can_mask for 'SFF only' frame filtering */
if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
/* reduce condition testing at receive time */
*can_id &= *mask;
/* inverse can_id/can_mask filter */
if (inv)
return &dev_rcv_lists->rx[RX_INV];
/* mask == 0 => no condition testing at receive time */
if (!(*mask))
return &dev_rcv_lists->rx[RX_ALL];
/* extra filterlists for the subscription of a single non-RTR can_id */
if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
!(*can_id & CAN_RTR_FLAG)) {
if (*can_id & CAN_EFF_FLAG) {
if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
return &dev_rcv_lists->rx_eff[effhash(*can_id)];
} else {
if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
return &dev_rcv_lists->rx_sff[*can_id];
}
}
/* default: filter via can_id/can_mask */
return &dev_rcv_lists->rx[RX_FIL];
}
/**
* can_rx_register - subscribe CAN frames from a specific interface
* @net: the applicable net namespace
* @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
* @can_id: CAN identifier (see description)
* @mask: CAN mask (see description)
* @func: callback function on filter match
* @data: returned parameter for callback function
* @ident: string for calling module identification
* @sk: socket pointer (might be NULL)
*
* Description:
* Invokes the callback function with the received sk_buff and the given
* parameter 'data' on a matching receive filter. A filter matches, when
*
* <received_can_id> & mask == can_id & mask
*
* The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
* filter for error message frames (CAN_ERR_FLAG bit set in mask).
*
* The provided pointer to the sk_buff is guaranteed to be valid as long as
* the callback function is running. The callback function must *not* free
* the given sk_buff while processing it's task. When the given sk_buff is
* needed after the end of the callback function it must be cloned inside
* the callback function with skb_clone().
*
* Return:
* 0 on success
* -ENOMEM on missing cache mem to create subscription entry
* -ENODEV unknown device
*/
int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
canid_t mask, void (*func)(struct sk_buff *, void *),
void *data, char *ident, struct sock *sk)
{
struct receiver *rcv;
struct hlist_head *rcv_list;
struct can_dev_rcv_lists *dev_rcv_lists;
struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
/* insert new receiver (dev,canid,mask) -> (func,data) */
if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev)))
return -ENODEV;
if (dev && !net_eq(net, dev_net(dev)))
return -ENODEV;
rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
if (!rcv)
return -ENOMEM;
spin_lock_bh(&net->can.rcvlists_lock);
dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
rcv->can_id = can_id;
rcv->mask = mask;
rcv->matches = 0;
rcv->func = func;
rcv->data = data;
rcv->ident = ident;
rcv->sk = sk;
hlist_add_head_rcu(&rcv->list, rcv_list);
dev_rcv_lists->entries++;
rcv_lists_stats->rcv_entries++;
rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
rcv_lists_stats->rcv_entries);
spin_unlock_bh(&net->can.rcvlists_lock);
return 0;
}
EXPORT_SYMBOL(can_rx_register);
/* can_rx_delete_receiver - rcu callback for single receiver entry removal */
static void can_rx_delete_receiver(struct rcu_head *rp)
{
struct receiver *rcv = container_of(rp, struct receiver, rcu);
struct sock *sk = rcv->sk;
kmem_cache_free(rcv_cache, rcv);
if (sk)
sock_put(sk);
}
/**
* can_rx_unregister - unsubscribe CAN frames from a specific interface
* @net: the applicable net namespace
* @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
* @can_id: CAN identifier
* @mask: CAN mask
* @func: callback function on filter match
* @data: returned parameter for callback function
*
* Description:
* Removes subscription entry depending on given (subscription) values.
*/
void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
canid_t mask, void (*func)(struct sk_buff *, void *),
void *data)
{
struct receiver *rcv = NULL;
struct hlist_head *rcv_list;
struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
struct can_dev_rcv_lists *dev_rcv_lists;
if (dev && dev->type != ARPHRD_CAN)
return;
if (dev && !net_eq(net, dev_net(dev)))
return;
spin_lock_bh(&net->can.rcvlists_lock);
dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
/* Search the receiver list for the item to delete. This should
* exist, since no receiver may be unregistered that hasn't
* been registered before.
*/
hlist_for_each_entry_rcu(rcv, rcv_list, list) {
if (rcv->can_id == can_id && rcv->mask == mask &&
rcv->func == func && rcv->data == data)
break;
}
/* Check for bugs in CAN protocol implementations using af_can.c:
* 'rcv' will be NULL if no matching list item was found for removal.
* As this case may potentially happen when closing a socket while
* the notifier for removing the CAN netdev is running we just print
* a warning here.
*/
if (!rcv) {
pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
DNAME(dev), can_id, mask);
goto out;
}
hlist_del_rcu(&rcv->list);
dev_rcv_lists->entries--;
if (rcv_lists_stats->rcv_entries > 0)
rcv_lists_stats->rcv_entries--;
out:
spin_unlock_bh(&net->can.rcvlists_lock);
/* schedule the receiver item for deletion */
if (rcv) {
if (rcv->sk)
sock_hold(rcv->sk);
call_rcu(&rcv->rcu, can_rx_delete_receiver);
}
}
EXPORT_SYMBOL(can_rx_unregister);
static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
{
rcv->func(skb, rcv->data);
rcv->matches++;
}
static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
{
struct receiver *rcv;
int matches = 0;
struct can_frame *cf = (struct can_frame *)skb->data;
canid_t can_id = cf->can_id;
if (dev_rcv_lists->entries == 0)
return 0;
if (can_id & CAN_ERR_FLAG) {
/* check for error message frame entries only */
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
if (can_id & rcv->mask) {
deliver(skb, rcv);
matches++;
}
}
return matches;
}
/* check for unfiltered entries */
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
deliver(skb, rcv);
matches++;
}
/* check for can_id/mask entries */
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
if ((can_id & rcv->mask) == rcv->can_id) {
deliver(skb, rcv);
matches++;
}
}
/* check for inverted can_id/mask entries */
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
if ((can_id & rcv->mask) != rcv->can_id) {
deliver(skb, rcv);
matches++;
}
}
/* check filterlists for single non-RTR can_ids */
if (can_id & CAN_RTR_FLAG)
return matches;
if (can_id & CAN_EFF_FLAG) {
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
if (rcv->can_id == can_id) {
deliver(skb, rcv);
matches++;
}
}
} else {
can_id &= CAN_SFF_MASK;
hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
deliver(skb, rcv);
matches++;
}
}
return matches;
}
static void can_receive(struct sk_buff *skb, struct net_device *dev)
{
struct can_dev_rcv_lists *dev_rcv_lists;
struct net *net = dev_net(dev);
struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
int matches;
/* update statistics */
pkg_stats->rx_frames++;
pkg_stats->rx_frames_delta++;
/* create non-zero unique skb identifier together with *skb */
while (!(can_skb_prv(skb)->skbcnt))
can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
rcu_read_lock();
/* deliver the packet to sockets listening on all devices */
matches = can_rcv_filter(net->can.rx_alldev_list, skb);
/* find receive list for this device */
dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
matches += can_rcv_filter(dev_rcv_lists, skb);
rcu_read_unlock();
/* consume the skbuff allocated by the netdevice driver */
consume_skb(skb);
if (matches > 0) {
pkg_stats->matches++;
pkg_stats->matches_delta++;
}
}
static int can_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
dev->type, skb->len);
kfree_skb(skb);
return NET_RX_DROP;
}
can_receive(skb, dev);
return NET_RX_SUCCESS;
}
static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
dev->type, skb->len);
kfree_skb(skb);
return NET_RX_DROP;
}
can_receive(skb, dev);
return NET_RX_SUCCESS;
}
static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
dev->type, skb->len);
kfree_skb(skb);
return NET_RX_DROP;
}
can_receive(skb, dev);
return NET_RX_SUCCESS;
}
/* af_can protocol functions */
/**
* can_proto_register - register CAN transport protocol
* @cp: pointer to CAN protocol structure
*
* Return:
* 0 on success
* -EINVAL invalid (out of range) protocol number
* -EBUSY protocol already in use
* -ENOBUF if proto_register() fails
*/
int can_proto_register(const struct can_proto *cp)
{
int proto = cp->protocol;
int err = 0;
if (proto < 0 || proto >= CAN_NPROTO) {
pr_err("can: protocol number %d out of range\n", proto);
return -EINVAL;
}
err = proto_register(cp->prot, 0);
if (err < 0)
return err;
mutex_lock(&proto_tab_lock);
if (rcu_access_pointer(proto_tab[proto])) {
pr_err("can: protocol %d already registered\n", proto);
err = -EBUSY;
} else {
RCU_INIT_POINTER(proto_tab[proto], cp);
}
mutex_unlock(&proto_tab_lock);
if (err < 0)
proto_unregister(cp->prot);
return err;
}
EXPORT_SYMBOL(can_proto_register);
/**
* can_proto_unregister - unregister CAN transport protocol
* @cp: pointer to CAN protocol structure
*/
void can_proto_unregister(const struct can_proto *cp)
{
int proto = cp->protocol;
mutex_lock(&proto_tab_lock);
BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
RCU_INIT_POINTER(proto_tab[proto], NULL);
mutex_unlock(&proto_tab_lock);
synchronize_rcu();
proto_unregister(cp->prot);
}
EXPORT_SYMBOL(can_proto_unregister);
static int can_pernet_init(struct net *net)
{
spin_lock_init(&net->can.rcvlists_lock);
net->can.rx_alldev_list =
kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
if (!net->can.rx_alldev_list)
goto out;
net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
if (!net->can.pkg_stats)
goto out_free_rx_alldev_list;
net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
if (!net->can.rcv_lists_stats)
goto out_free_pkg_stats;
if (IS_ENABLED(CONFIG_PROC_FS)) {
/* the statistics are updated every second (timer triggered) */
if (stats_timer) {
timer_setup(&net->can.stattimer, can_stat_update,
0);
mod_timer(&net->can.stattimer,
round_jiffies(jiffies + HZ));
}
net->can.pkg_stats->jiffies_init = jiffies;
can_init_proc(net);
}
return 0;
out_free_pkg_stats:
kfree(net->can.pkg_stats);
out_free_rx_alldev_list:
kfree(net->can.rx_alldev_list);
out:
return -ENOMEM;
}
static void can_pernet_exit(struct net *net)
{
if (IS_ENABLED(CONFIG_PROC_FS)) {
can_remove_proc(net);
if (stats_timer)
del_timer_sync(&net->can.stattimer);
}
kfree(net->can.rx_alldev_list);
kfree(net->can.pkg_stats);
kfree(net->can.rcv_lists_stats);
}
/* af_can module init/exit functions */
static struct packet_type can_packet __read_mostly = {
.type = cpu_to_be16(ETH_P_CAN),
.func = can_rcv,
};
static struct packet_type canfd_packet __read_mostly = {
.type = cpu_to_be16(ETH_P_CANFD),
.func = canfd_rcv,
};
static struct packet_type canxl_packet __read_mostly = {
.type = cpu_to_be16(ETH_P_CANXL),
.func = canxl_rcv,
};
static const struct net_proto_family can_family_ops = {
.family = PF_CAN,
.create = can_create,
.owner = THIS_MODULE,
};
static struct pernet_operations can_pernet_ops __read_mostly = {
.init = can_pernet_init,
.exit = can_pernet_exit,
};
static __init int can_init(void)
{
int err;
/* check for correct padding to be able to use the structs similarly */
BUILD_BUG_ON(offsetof(struct can_frame, len) !=
offsetof(struct canfd_frame, len) ||
offsetof(struct can_frame, len) !=
offsetof(struct canxl_frame, flags) ||
offsetof(struct can_frame, data) !=
offsetof(struct canfd_frame, data));
pr_info("can: controller area network core\n");
rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
0, 0, NULL);
if (!rcv_cache)
return -ENOMEM;
err = register_pernet_subsys(&can_pernet_ops);
if (err)
goto out_pernet;
/* protocol register */
err = sock_register(&can_family_ops);
if (err)
goto out_sock;
dev_add_pack(&can_packet);
dev_add_pack(&canfd_packet);
dev_add_pack(&canxl_packet);
return 0;
out_sock:
unregister_pernet_subsys(&can_pernet_ops);
out_pernet:
kmem_cache_destroy(rcv_cache);
return err;
}
static __exit void can_exit(void)
{
/* protocol unregister */
dev_remove_pack(&canxl_packet);
dev_remove_pack(&canfd_packet);
dev_remove_pack(&can_packet);
sock_unregister(PF_CAN);
unregister_pernet_subsys(&can_pernet_ops);
rcu_barrier(); /* Wait for completion of call_rcu()'s */
kmem_cache_destroy(rcv_cache);
}
module_init(can_init);
module_exit(can_exit);
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