// 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "af_can.h" MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); MODULE_LICENSE("Dual BSD/GPL"); MODULE_AUTHOR("Urs Thuermann , " "Oliver Hartkopp "); 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 canfd_frame *cfd = (struct canfd_frame *)skb->data; struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats; int err = -EINVAL; if (skb->len == CAN_MTU) { skb->protocol = htons(ETH_P_CAN); if (unlikely(cfd->len > CAN_MAX_DLEN)) goto inval_skb; } else if (skb->len == CANFD_MTU) { skb->protocol = htons(ETH_P_CANFD); if (unlikely(cfd->len > CANFD_MAX_DLEN)) goto inval_skb; } else { goto inval_skb; } /* Make sure the CAN frame can pass the selected CAN netdevice. * As structs can_frame and canfd_frame are similar, we can provide * CAN FD frames to legacy CAN drivers as long as the length is <= 8 */ if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) { 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_ni(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 *ml_priv = dev->ml_priv; return &ml_priv->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 * @d: 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 * * & 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. * Constistency 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 * @dev: pointer to netdevice (NULL => subcribe 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 * * & 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; int err = 0; /* insert new receiver (dev,canid,mask) -> (func,data) */ if (dev && dev->type != ARPHRD_CAN) 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 err; } 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 * @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. */ if (!rcv) { WARN(1, "BUG: 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) { struct canfd_frame *cfd = (struct canfd_frame *)skb->data; if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU || cfd->len > CAN_MAX_DLEN)) { pr_warn_once("PF_CAN: dropped non conform CAN skbuf: dev type %d, len %d, datalen %d\n", dev->type, skb->len, cfd->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) { struct canfd_frame *cfd = (struct canfd_frame *)skb->data; if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU || cfd->len > CANFD_MAX_DLEN)) { pr_warn_once("PF_CAN: dropped non conform CAN FD skbuf: dev type %d, len %d, datalen %d\n", dev->type, skb->len, cfd->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); /* af_can notifier to create/remove CAN netdevice specific structs */ static int can_notifier(struct notifier_block *nb, unsigned long msg, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); if (dev->type != ARPHRD_CAN) return NOTIFY_DONE; switch (msg) { case NETDEV_REGISTER: WARN(!dev->ml_priv, "No CAN mid layer private allocated, please fix your driver and use alloc_candev()!\n"); break; } return NOTIFY_DONE; } 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 const struct net_proto_family can_family_ops = { .family = PF_CAN, .create = can_create, .owner = THIS_MODULE, }; /* notifier block for netdevice event */ static struct notifier_block can_netdev_notifier __read_mostly = { .notifier_call = can_notifier, }; 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, can_dlc) != offsetof(struct canfd_frame, len) || offsetof(struct can_frame, data) != offsetof(struct canfd_frame, data)); pr_info("can: controller area network core (" CAN_VERSION_STRING ")\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; err = register_netdevice_notifier(&can_netdev_notifier); if (err) goto out_notifier; dev_add_pack(&can_packet); dev_add_pack(&canfd_packet); return 0; out_notifier: sock_unregister(PF_CAN); 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(&canfd_packet); dev_remove_pack(&can_packet); unregister_netdevice_notifier(&can_netdev_notifier); 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);