diff options
Diffstat (limited to 'net/can/bcm.c')
| -rw-r--r-- | net/can/bcm.c | 2215 |
1 files changed, 2215 insertions, 0 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c new file mode 100644 index 000000000..3d637a1e0 --- /dev/null +++ b/net/can/bcm.c @@ -0,0 +1,2215 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +/* + * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content + * + * 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/init.h> +#include <linux/interrupt.h> +#include <linux/hrtimer.h> +#include <linux/list.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/uio.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/skb.h> +#include <linux/can/bcm.h> +#include <linux/slab.h> +#include <linux/workqueue.h> +#include <linux/spinlock.h> +#include <net/can.h> +#include <net/sock.h> +#include <net/net_namespace.h> + +/* + * To send multiple CAN frame content within TX_SETUP or to filter + * CAN messages with multiplex index within RX_SETUP, the number of + * different filters is limited to 256 due to the one byte index value. + */ +#define MAX_NFRAMES 256 + +/* limit timers to 400 days for sending/timeouts */ +#define BCM_TIMER_SEC_MAX (400 * 24 * 60 * 60) + +/* use of last_frames[index].flags */ +#define RX_LOCAL 0x10 /* frame was created on the local host */ +#define RX_OWN 0x20 /* frame was sent via the socket it was received on */ +#define RX_RECV 0x40 /* received data for this element */ +#define RX_THR 0x80 /* element not been sent due to throttle feature */ +#define BCM_CAN_FLAGS_MASK 0x0F /* to clean private flags after usage */ + +/* get best masking value for can_rx_register() for a given single can_id */ +#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \ + (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \ + (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG)) + +MODULE_DESCRIPTION("PF_CAN broadcast manager protocol"); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); +MODULE_ALIAS("can-proto-2"); + +#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex) + +static struct workqueue_struct *bcm_wq; + +/* + * easy access to the first 64 bit of can(fd)_frame payload. cp->data is + * 64 bit aligned so the offset has to be multiples of 8 which is ensured + * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler(). + */ +static inline u64 get_u64(const struct canfd_frame *cp, int offset) +{ + return *(u64 *)(cp->data + offset); +} + +struct bcm_op { + struct list_head list; + struct rcu_head rcu; + struct work_struct work; + int ifindex; + canid_t can_id; + u32 flags; + atomic_long_t frames_abs, frames_filtered; + struct bcm_timeval ival1, ival2; + struct hrtimer timer, thrtimer; + ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg; + int rx_ifindex; + int if_detected; /* first received ifindex in ANYDEV rx_op mode */ + int cfsiz; + u32 count; + u32 nframes; + u32 currframe; + /* void pointers to arrays of struct can[fd]_frame */ + void *frames; + void *last_frames; + struct canfd_frame sframe; + struct canfd_frame last_sframe; + struct sock *sk; + struct net_device *rx_reg_dev; + netdevice_tracker rx_reg_dev_tracker; + spinlock_t bcm_tx_lock; /* protect tx data and timer updates */ + spinlock_t bcm_rx_update_lock; /* protect filter/timer data updates */ +}; + +struct bcm_sock { + struct sock sk; + int bound; + int ifindex; + struct list_head notifier; + struct list_head rx_ops; + struct list_head tx_ops; + unsigned long dropped_usr_msgs; + struct proc_dir_entry *bcm_proc_read; + char procname [32]; /* inode number in decimal with \0 */ +}; + +static LIST_HEAD(bcm_notifier_list); +static DEFINE_SPINLOCK(bcm_notifier_lock); +static struct bcm_sock *bcm_busy_notifier; + +/* Return pointer to store the extra msg flags for bcm_recvmsg(). + * We use the space of one unsigned int beyond the 'struct sockaddr_can' + * in skb->cb. + */ +static inline unsigned int *bcm_flags(struct sk_buff *skb) +{ + /* return pointer after struct sockaddr_can */ + return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]); +} + +static inline struct bcm_sock *bcm_sk(const struct sock *sk) +{ + return (struct bcm_sock *)sk; +} + +static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv) +{ + return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC); +} + +/* check limitations for timeval provided by user */ +static bool bcm_is_invalid_tv(struct bcm_msg_head *msg_head) +{ + if ((msg_head->ival1.tv_sec < 0) || + (msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) || + (msg_head->ival1.tv_usec < 0) || + (msg_head->ival1.tv_usec >= USEC_PER_SEC) || + (msg_head->ival2.tv_sec < 0) || + (msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) || + (msg_head->ival2.tv_usec < 0) || + (msg_head->ival2.tv_usec >= USEC_PER_SEC)) + return true; + + return false; +} + +#define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU) +#define OPSIZ sizeof(struct bcm_op) +#define MHSIZ sizeof(struct bcm_msg_head) + +/* + * procfs functions + */ +#if IS_ENABLED(CONFIG_PROC_FS) +static char *bcm_proc_getifname(struct net *net, char *result, int ifindex) +{ + struct net_device *dev; + + if (!ifindex) + return "any"; + + rcu_read_lock(); + dev = dev_get_by_index_rcu(net, ifindex); + if (dev) + strcpy(result, dev->name); + else + strcpy(result, "???"); + rcu_read_unlock(); + + return result; +} + +static int bcm_proc_show(struct seq_file *m, void *v) +{ + char ifname[IFNAMSIZ]; + struct net *net = m->private; + struct sock *sk = (struct sock *)pde_data(m->file->f_inode); + struct bcm_sock *bo = bcm_sk(sk); + struct bcm_op *op; + + seq_printf(m, ">>> socket %pK", sk->sk_socket); + seq_printf(m, " / sk %pK", sk); + seq_printf(m, " / bo %pK", bo); + seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs); + seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex)); + seq_printf(m, " <<<\n"); + + rcu_read_lock(); + + list_for_each_entry_rcu(op, &bo->rx_ops, list) { + + long reduction, frames_filtered, frames_abs; + + frames_filtered = atomic_long_read(&op->frames_filtered); + frames_abs = atomic_long_read(&op->frames_abs); + + /* print only active entries & prevent division by zero */ + if (!frames_abs) + continue; + + seq_printf(m, "rx_op: %03X %-5s ", op->can_id, + bcm_proc_getifname(net, ifname, op->ifindex)); + + if (op->flags & CAN_FD_FRAME) + seq_printf(m, "(%u)", op->nframes); + else + seq_printf(m, "[%u]", op->nframes); + + seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' '); + + if (op->kt_ival1) + seq_printf(m, "timeo=%lld ", + (long long)ktime_to_us(op->kt_ival1)); + + if (op->kt_ival2) + seq_printf(m, "thr=%lld ", + (long long)ktime_to_us(op->kt_ival2)); + + seq_printf(m, "# recv %ld (%ld) => reduction: ", + frames_filtered, frames_abs); + + reduction = 100 - (frames_filtered * 100) / frames_abs; + + seq_printf(m, "%s%ld%%\n", + (reduction == 100) ? "near " : "", reduction); + } + + list_for_each_entry_rcu(op, &bo->tx_ops, list) { + + seq_printf(m, "tx_op: %03X %s ", op->can_id, + bcm_proc_getifname(net, ifname, op->ifindex)); + + if (op->flags & CAN_FD_FRAME) + seq_printf(m, "(%u) ", op->nframes); + else + seq_printf(m, "[%u] ", op->nframes); + + if (op->kt_ival1) + seq_printf(m, "t1=%lld ", + (long long)ktime_to_us(op->kt_ival1)); + + if (op->kt_ival2) + seq_printf(m, "t2=%lld ", + (long long)ktime_to_us(op->kt_ival2)); + + seq_printf(m, "# sent %ld\n", + atomic_long_read(&op->frames_abs)); + } + seq_putc(m, '\n'); + + rcu_read_unlock(); + + return 0; +} +#endif /* CONFIG_PROC_FS */ + +static void bcm_update_rx_stats(struct bcm_op *op) +{ + /* prevent overflow of the reduction% calculation in bcm_proc_show() */ + if (atomic_long_inc_return(&op->frames_abs) > LONG_MAX / 100) { + atomic_long_set(&op->frames_filtered, 0); + atomic_long_set(&op->frames_abs, 0); + } +} + +static void bcm_update_tx_stats(struct bcm_op *op) +{ + /* tx_op has no reduction% calculation - use the full range and + * just keep the displayed counter non-negative on overflow + */ + if (atomic_long_inc_return(&op->frames_abs) == LONG_MAX) + atomic_long_set(&op->frames_abs, 0); +} + +/* + * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface + * of the given bcm tx op + */ +static void bcm_can_tx(struct bcm_op *op, struct canfd_frame *cf) +{ + struct sk_buff *skb; + struct can_skb_ext *csx; + struct net_device *dev; + struct canfd_frame cframe; + bool cyclic = !cf; + unsigned int idx = 0; + int err; + + /* no target device? => exit */ + if (!op->ifindex) + return; + + if (cyclic) { + /* read currframe under lock protection */ + spin_lock_bh(&op->bcm_tx_lock); + idx = op->currframe; + memcpy(&cframe, op->frames + op->cfsiz * idx, op->cfsiz); + cf = &cframe; + spin_unlock_bh(&op->bcm_tx_lock); + } + + dev = dev_get_by_index(sock_net(op->sk), op->ifindex); + if (!dev) { + /* RFC: should this bcm_op remove itself here? */ + return; + } + + skb = alloc_skb(op->cfsiz, gfp_any()); + if (!skb) + goto out; + + csx = can_skb_ext_add(skb); + if (!csx) { + kfree_skb(skb); + goto out; + } + + csx->can_iif = dev->ifindex; + + skb_put_data(skb, cf, op->cfsiz); + + /* send with loopback */ + skb->dev = dev; + can_skb_set_owner(skb, op->sk); + err = can_send(skb, 1); + + /* update currframe and count under lock protection */ + spin_lock_bh(&op->bcm_tx_lock); + + if (!err) + bcm_update_tx_stats(op); + + /* only advance the cyclic sequence if nothing reset currframe while + * we were sending - a concurrent TX_RESET_MULTI_IDX means this + * frame's bookkeeping belongs to a sequence that no longer exists + */ + if (!cyclic || op->currframe == idx) { + op->currframe++; + + /* reached last frame? */ + if (op->currframe >= op->nframes) + op->currframe = 0; + + if (op->count > 0) + op->count--; + } + + spin_unlock_bh(&op->bcm_tx_lock); +out: + dev_put(dev); +} + +/* + * bcm_send_to_user - send a BCM message to the userspace + * (consisting of bcm_msg_head + x CAN frames) + */ +static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head, + struct canfd_frame *frames, int has_timestamp) +{ + struct sk_buff *skb; + struct canfd_frame *firstframe; + struct sockaddr_can *addr; + struct sock *sk = op->sk; + unsigned int datalen = head->nframes * op->cfsiz; + unsigned int *pflags; + enum skb_drop_reason reason; + + skb = alloc_skb(sizeof(*head) + datalen, gfp_any()); + if (!skb) + return; + + skb_put_data(skb, head, sizeof(*head)); + + /* ensure space for sockaddr_can and msg flags */ + sock_skb_cb_check_size(sizeof(struct sockaddr_can) + + sizeof(unsigned int)); + + /* initialize msg flags */ + pflags = bcm_flags(skb); + *pflags = 0; + + if (head->nframes) { + /* CAN frames starting here */ + firstframe = (struct canfd_frame *)skb_tail_pointer(skb); + + skb_put_data(skb, frames, datalen); + + /* + * the BCM uses the flags-element of the canfd_frame + * structure for internal purposes. This is only + * relevant for updates that are generated by the + * BCM, where nframes is 1 + */ + if (head->nframes == 1) { + if (firstframe->flags & RX_LOCAL) + *pflags |= MSG_DONTROUTE; + if (firstframe->flags & RX_OWN) + *pflags |= MSG_CONFIRM; + + firstframe->flags &= BCM_CAN_FLAGS_MASK; + } + } + + if (has_timestamp) { + /* restore rx timestamp */ + skb->tstamp = op->rx_stamp; + } + + /* + * Put the datagram to the queue so that bcm_recvmsg() can + * get it from there. We need to pass the interface index to + * bcm_recvmsg(). We pass a whole struct sockaddr_can in skb->cb + * containing the interface index. + */ + + addr = (struct sockaddr_can *)skb->cb; + memset(addr, 0, sizeof(*addr)); + addr->can_family = AF_CAN; + addr->can_ifindex = op->rx_ifindex; + + reason = sock_queue_rcv_skb_reason(sk, skb); + if (reason) { + struct bcm_sock *bo = bcm_sk(sk); + + sk_skb_reason_drop(sk, skb, reason); + /* don't care about overflows in this statistic */ + bo->dropped_usr_msgs++; + } +} + +static bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt) +{ + ktime_t ival; + + spin_lock_bh(&op->bcm_tx_lock); + + if (op->kt_ival1 && op->count) + ival = op->kt_ival1; + else if (op->kt_ival2) { + ival = op->kt_ival2; + } else { + spin_unlock_bh(&op->bcm_tx_lock); + return false; + } + + spin_unlock_bh(&op->bcm_tx_lock); + + hrtimer_set_expires(hrt, ktime_add(ktime_get(), ival)); + return true; +} + +static void bcm_tx_start_timer(struct bcm_op *op) +{ + if (bcm_tx_set_expiry(op, &op->timer)) + hrtimer_start_expires(&op->timer, HRTIMER_MODE_ABS_SOFT); +} + +/* bcm_tx_timeout_handler - performs cyclic CAN frame transmissions */ +static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer) +{ + struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer); + struct bcm_msg_head msg_head; + bool tx_ival1, tx_ival2; + + /* snapshot kt_ival1/kt_ival2/count under lock to avoid torn + * ktime_t reads racing with concurrent bcm_tx_setup() updates + */ + spin_lock_bh(&op->bcm_tx_lock); + tx_ival1 = op->kt_ival1 && (op->count > 0); + tx_ival2 = !!op->kt_ival2; + spin_unlock_bh(&op->bcm_tx_lock); + + if (tx_ival1) { + u32 flags, count; + struct bcm_timeval ival1, ival2; + + bcm_can_tx(op, NULL); + + /* snapshot variables under lock to avoid torn reads racing + * with concurrent bcm_tx_setup() updates + */ + spin_lock_bh(&op->bcm_tx_lock); + flags = op->flags; + count = op->count; + ival1 = op->ival1; + ival2 = op->ival2; + spin_unlock_bh(&op->bcm_tx_lock); + + if (!count && (flags & TX_COUNTEVT)) { + /* create notification to user */ + memset(&msg_head, 0, sizeof(msg_head)); + msg_head.opcode = TX_EXPIRED; + msg_head.flags = flags; + msg_head.count = count; + msg_head.ival1 = ival1; + msg_head.ival2 = ival2; + msg_head.can_id = op->can_id; + msg_head.nframes = 0; + + bcm_send_to_user(op, &msg_head, NULL, 0); + } + + } else if (tx_ival2) { + bcm_can_tx(op, NULL); + } + + return bcm_tx_set_expiry(op, &op->timer) ? + HRTIMER_RESTART : HRTIMER_NORESTART; +} + +/* + * bcm_rx_changed - create a RX_CHANGED notification due to changed content + */ +static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data) +{ + struct bcm_msg_head head; + + /* update statistics (frames_filtered <= frames_abs) */ + if (atomic_long_read(&op->frames_abs)) + atomic_long_inc(&op->frames_filtered); + + /* this element is not throttled anymore */ + data->flags &= ~RX_THR; + + memset(&head, 0, sizeof(head)); + head.opcode = RX_CHANGED; + head.flags = op->flags; + head.count = op->count; + head.ival1 = op->ival1; + head.ival2 = op->ival2; + head.can_id = op->can_id; + head.nframes = 1; + + bcm_send_to_user(op, &head, data, 1); +} + +/* + * bcm_rx_update_and_send - process a detected relevant receive content change + * 1. update the last received data + * 2. send a notification to the user (if possible) + */ +static void bcm_rx_update_and_send(struct bcm_op *op, + struct canfd_frame *lastdata, + const struct canfd_frame *rxdata, + unsigned char traffic_flags) +{ + memcpy(lastdata, rxdata, op->cfsiz); + + /* mark as used and throttled by default */ + lastdata->flags |= (RX_RECV|RX_THR); + + /* add own/local/remote traffic flags */ + lastdata->flags |= traffic_flags; + + /* throttling mode inactive ? */ + if (!op->kt_ival2) { + /* send RX_CHANGED to the user immediately */ + bcm_rx_changed(op, lastdata); + return; + } + + /* with active throttling timer we are just done here */ + if (hrtimer_active(&op->thrtimer)) + return; + + /* first reception with enabled throttling mode */ + if (!op->kt_lastmsg) + goto rx_changed_settime; + + /* got a second frame inside a potential throttle period? */ + if (ktime_us_delta(ktime_get(), op->kt_lastmsg) < + ktime_to_us(op->kt_ival2)) { + /* do not send the saved data - only start throttle timer */ + hrtimer_start(&op->thrtimer, + ktime_add(op->kt_lastmsg, op->kt_ival2), + HRTIMER_MODE_ABS_SOFT); + return; + } + + /* the gap was that big, that throttling was not needed here */ +rx_changed_settime: + bcm_rx_changed(op, lastdata); + op->kt_lastmsg = ktime_get(); +} + +/* + * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly + * received data stored in op->last_frames[] + */ +static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index, + const struct canfd_frame *rxdata, + unsigned char traffic_flags) +{ + struct canfd_frame *cf = op->frames + op->cfsiz * index; + struct canfd_frame *lcf = op->last_frames + op->cfsiz * index; + int i; + + /* + * no one uses the MSBs of flags for comparison, + * so we use it here to detect the first time of reception + */ + + if (!(lcf->flags & RX_RECV)) { + /* received data for the first time => send update to user */ + bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags); + return; + } + + /* do a real check in CAN frame data section */ + for (i = 0; i < rxdata->len; i += 8) { + if ((get_u64(cf, i) & get_u64(rxdata, i)) != + (get_u64(cf, i) & get_u64(lcf, i))) { + bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags); + return; + } + } + + if (op->flags & RX_CHECK_DLC) { + /* do a real check in CAN frame length */ + if (rxdata->len != lcf->len) { + bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags); + return; + } + } +} + +/* + * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception + */ +static void bcm_rx_starttimer(struct bcm_op *op) +{ + if (op->flags & RX_NO_AUTOTIMER) + return; + + if (op->kt_ival1) + hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL_SOFT); +} + +/* bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out */ +static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer) +{ + struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer); + struct bcm_msg_head msg_head; + + spin_lock_bh(&op->bcm_rx_update_lock); + + /* if user wants to be informed, when cyclic CAN-Messages come back */ + if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) { + /* clear received CAN frames to indicate 'nothing received' */ + memset(op->last_frames, 0, op->nframes * op->cfsiz); + } + + /* create notification to user */ + memset(&msg_head, 0, sizeof(msg_head)); + msg_head.opcode = RX_TIMEOUT; + msg_head.flags = op->flags; + msg_head.count = op->count; + msg_head.ival1 = op->ival1; + msg_head.ival2 = op->ival2; + msg_head.can_id = op->can_id; + msg_head.nframes = 0; + + spin_unlock_bh(&op->bcm_rx_update_lock); + + bcm_send_to_user(op, &msg_head, NULL, 0); + + return HRTIMER_NORESTART; +} + +/* + * bcm_rx_do_flush - helper for bcm_rx_thr_flush + */ +static inline int bcm_rx_do_flush(struct bcm_op *op, unsigned int index) +{ + struct canfd_frame *lcf = op->last_frames + op->cfsiz * index; + + if ((op->last_frames) && (lcf->flags & RX_THR)) { + bcm_rx_changed(op, lcf); + return 1; + } + return 0; +} + +/* + * bcm_rx_thr_flush - Check for throttled data and send it to the userspace + */ +static int bcm_rx_thr_flush(struct bcm_op *op) +{ + int updated = 0; + + if (op->nframes > 1) { + unsigned int i; + + /* for MUX filter we start at index 1 */ + for (i = 1; i < op->nframes; i++) + updated += bcm_rx_do_flush(op, i); + + } else { + /* for RX_FILTER_ID and simple filter */ + updated += bcm_rx_do_flush(op, 0); + } + + return updated; +} + +/* + * bcm_rx_thr_handler - the time for blocked content updates is over now: + * Check for throttled data and send it to the userspace + */ +static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer) +{ + struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer); + enum hrtimer_restart ret; + + spin_lock_bh(&op->bcm_rx_update_lock); + + /* kt_ival2 may have been concurrently cleared by bcm_rx_setup() + * before it cancels this timer - never forward with a zero + * interval in that case. + */ + if (bcm_rx_thr_flush(op) && op->kt_ival2) { + hrtimer_forward_now(hrtimer, op->kt_ival2); + ret = HRTIMER_RESTART; + } else { + /* rearm throttle handling */ + op->kt_lastmsg = 0; + ret = HRTIMER_NORESTART; + } + + spin_unlock_bh(&op->bcm_rx_update_lock); + + return ret; +} + +/* + * bcm_rx_handler - handle a CAN frame reception + */ +static void bcm_rx_handler(struct sk_buff *skb, void *data) +{ + struct bcm_op *op = (struct bcm_op *)data; + const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data; + struct canfd_frame rtrframe; + unsigned int i; + unsigned char traffic_flags; + bool rtr_frame; + + if (op->can_id != rxframe->can_id) + return; + + /* make sure to handle the correct frame type (CAN / CAN FD) */ + if (op->flags & CAN_FD_FRAME) { + if (!can_is_canfd_skb(skb)) + return; + } else { + if (!can_is_can_skb(skb)) + return; + } + + /* An ANYDEV op with an active RX timeout and/or throttle timer + * tracks a single source interface: claim the first interface that + * delivers a matching frame and reject frames from any other one, + * before hrtimer_cancel() below can touch op->timer - this avoids + * racing bcm_rx_timeout_handler() across concurrent interfaces. + * RX_RTR_FRAME ops are excluded, as kt_ival1/kt_ival2 may briefly + * hold a stale value from an earlier non-RTR configuration. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + + if (!(op->flags & RX_RTR_FRAME) && + (op->kt_ival1 || op->kt_ival2)) { + /* don't claim to vanishing interface */ + if (!op->if_detected && + READ_ONCE(skb->dev->reg_state) == NETREG_REGISTERED) + op->if_detected = skb->dev->ifindex; + + if (op->if_detected != skb->dev->ifindex) { + spin_unlock_bh(&op->bcm_rx_update_lock); + return; + } + } + + spin_unlock_bh(&op->bcm_rx_update_lock); + } + + /* disable timeout */ + hrtimer_cancel(&op->timer); + + /* op->flags/op->frames may be updated concurrently by bcm_rx_setup() */ + spin_lock_bh(&op->bcm_rx_update_lock); + + rtr_frame = op->flags & RX_RTR_FRAME; + if (rtr_frame) { + bcm_update_rx_stats(op); + /* snapshot RTR content under lock */ + memcpy(&rtrframe, op->frames, op->cfsiz); + spin_unlock_bh(&op->bcm_rx_update_lock); + + /* send reply for RTR-request (placed in op->frames[0]) */ + bcm_can_tx(op, &rtrframe); + return; + } + + /* update statistics in the same critical section as bcm_rx_changed() + * below: frames_filtered must never be checked/incremented against a + * frames_abs snapshot from a concurrent bcm_rx_handler() call on + * another CPU for the same (wildcard) op, or frames_filtered can end + * up larger than frames_abs. + */ + bcm_update_rx_stats(op); + + /* compute flags to distinguish between own/local/remote CAN traffic */ + traffic_flags = 0; + if (skb->sk) { + traffic_flags |= RX_LOCAL; + if (skb->sk == op->sk) + traffic_flags |= RX_OWN; + } + + /* save rx timestamp and originator for recvfrom() under lock: an + * ANYDEV op without an active timer can still run concurrently on + * different CPUs, so content and meta data must be bundled here. + */ + op->rx_stamp = skb->tstamp; + op->rx_ifindex = skb->dev->ifindex; + + if (op->flags & RX_FILTER_ID) { + /* the easiest case */ + bcm_rx_update_and_send(op, op->last_frames, rxframe, + traffic_flags); + goto rx_starttimer; + } + + if (op->nframes == 1) { + /* simple compare with index 0 */ + bcm_rx_cmp_to_index(op, 0, rxframe, traffic_flags); + goto rx_starttimer; + } + + if (op->nframes > 1) { + /* + * multiplex compare + * + * find the first multiplex mask that fits. + * Remark: The MUX-mask is stored in index 0 - but only the + * first 64 bits of the frame data[] are relevant (CAN FD) + */ + + for (i = 1; i < op->nframes; i++) { + if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) == + (get_u64(op->frames, 0) & + get_u64(op->frames + op->cfsiz * i, 0))) { + bcm_rx_cmp_to_index(op, i, rxframe, + traffic_flags); + break; + } + } + } + +rx_starttimer: + bcm_rx_starttimer(op); + + spin_unlock_bh(&op->bcm_rx_update_lock); +} + +/* + * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements + */ +static struct bcm_op *bcm_find_op(struct list_head *ops, + struct bcm_msg_head *mh, int ifindex) +{ + struct bcm_op *op; + + list_for_each_entry(op, ops, list) { + if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) && + (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) + return op; + } + + return NULL; +} + +static void bcm_free_op_work(struct work_struct *work) +{ + struct bcm_op *op = container_of(work, struct bcm_op, work); + + hrtimer_cancel(&op->timer); + hrtimer_cancel(&op->thrtimer); + + if ((op->frames) && (op->frames != &op->sframe)) + kfree(op->frames); + + if ((op->last_frames) && (op->last_frames != &op->last_sframe)) + kfree(op->last_frames); + + /* the last possible access to op->timer/op->thrtimer has now + * happened above via hrtimer_cancel() - op->sk is no longer + * needed by any pending timer callback, so drop our reference + */ + sock_put(op->sk); + + kfree(op); +} + +static void bcm_free_op_rcu(struct rcu_head *rcu_head) +{ + struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu); + + INIT_WORK(&op->work, bcm_free_op_work); + queue_work(bcm_wq, &op->work); +} + +static void bcm_remove_op(struct bcm_op *op) +{ + hrtimer_cancel(&op->timer); + hrtimer_cancel(&op->thrtimer); + + call_rcu(&op->rcu, bcm_free_op_rcu); +} + +static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op) +{ + if (op->rx_reg_dev == dev) { + can_rx_unregister(dev_net(dev), dev, op->can_id, + REGMASK(op->can_id), bcm_rx_handler, op); + + /* mark as removed subscription */ + op->rx_reg_dev = NULL; + netdev_put(dev, &op->rx_reg_dev_tracker); + } else + printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device " + "mismatch %p %p\n", op->rx_reg_dev, dev); +} + +/* + * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops) + */ +static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh, + int ifindex) +{ + struct bcm_op *op, *n; + + list_for_each_entry_safe(op, n, ops, list) { + if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) && + (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) { + + /* disable automatic timer on frame reception */ + op->flags |= RX_NO_AUTOTIMER; + + /* + * Don't care if we're bound or not (due to netdev + * problems) can_rx_unregister() is always a save + * thing to do here. + */ + if (op->ifindex) { + /* + * Only remove subscriptions that had not + * been removed due to NETDEV_UNREGISTER + * in bcm_notifier() + * + * op->rx_reg_dev is a tracked reference taken + * when the subscription was registered, so it + * stays valid here even if a concurrent + * NETDEV_UNREGISTER already unlisted the dev. + */ + if (op->rx_reg_dev) + bcm_rx_unreg(op->rx_reg_dev, op); + } else + can_rx_unregister(sock_net(op->sk), NULL, + op->can_id, + REGMASK(op->can_id), + bcm_rx_handler, op); + + list_del_rcu(&op->list); + bcm_remove_op(op); + return 1; /* done */ + } + } + + return 0; /* not found */ +} + +/* + * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops) + */ +static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh, + int ifindex) +{ + struct bcm_op *op, *n; + + list_for_each_entry_safe(op, n, ops, list) { + if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) && + (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) { + list_del_rcu(&op->list); + bcm_remove_op(op); + return 1; /* done */ + } + } + + return 0; /* not found */ +} + +/* + * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg) + */ +static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head, + int ifindex) +{ + struct bcm_op *op = bcm_find_op(ops, msg_head, ifindex); + + if (!op) + return -EINVAL; + + /* put current values into msg_head */ + msg_head->flags = op->flags; + msg_head->count = op->count; + msg_head->ival1 = op->ival1; + msg_head->ival2 = op->ival2; + msg_head->nframes = op->nframes; + + bcm_send_to_user(op, msg_head, op->frames, 0); + + return MHSIZ; +} + +/* + * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg) + */ +static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, + int ifindex, struct sock *sk) +{ + struct bcm_sock *bo = bcm_sk(sk); + struct bcm_op *op; + struct canfd_frame *cf; + bool add_op_to_list = false; + unsigned int i; + int err; + + /* we need a real device to send frames */ + if (!ifindex) + return -ENODEV; + + /* check nframes boundaries - we need at least one CAN frame */ + if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES) + return -EINVAL; + + /* check timeval limitations */ + if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head)) + return -EINVAL; + + /* check the given can_id */ + op = bcm_find_op(&bo->tx_ops, msg_head, ifindex); + if (op) { + void *new_frames; + + /* update existing BCM operation */ + + /* + * Do we need more space for the CAN frames than currently + * allocated? -> This is a _really_ unusual use-case and + * therefore (complexity / locking) it is not supported. + */ + if (msg_head->nframes > op->nframes) + return -E2BIG; + + /* get new CAN frames content into a staging buffer before + * locking: validate and normalize the frames there so that + * bcm_can_tx() / bcm_tx_timeout_handler() never observe a + * partially updated or unvalidated frame in op->frames + */ + new_frames = kmalloc(msg_head->nframes * op->cfsiz, GFP_KERNEL); + if (!new_frames) + return -ENOMEM; + + for (i = 0; i < msg_head->nframes; i++) { + + cf = new_frames + op->cfsiz * i; + err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz); + if (err < 0) { + kfree(new_frames); + return err; + } + + if (op->flags & CAN_FD_FRAME) { + if (cf->len > 64) + err = -EINVAL; + } else { + if (cf->len > 8) + err = -EINVAL; + } + + if (err < 0) { + kfree(new_frames); + return err; + } + + if (msg_head->flags & TX_CP_CAN_ID) { + /* copy can_id into frame */ + cf->can_id = msg_head->can_id; + } + } + + spin_lock_bh(&op->bcm_tx_lock); + + /* update CAN frames content */ + memcpy(op->frames, new_frames, msg_head->nframes * op->cfsiz); + + op->flags = msg_head->flags; + + if (op->nframes != msg_head->nframes || + op->flags & TX_RESET_MULTI_IDX) { + /* potentially update changed nframes */ + op->nframes = msg_head->nframes; + /* restart multiple frame transmission */ + op->currframe = 0; + } + + if (op->flags & SETTIMER) + op->count = msg_head->count; + + spin_unlock_bh(&op->bcm_tx_lock); + + kfree(new_frames); + + } else { + /* insert new BCM operation for the given can_id */ + + op = kzalloc(OPSIZ, GFP_KERNEL); + if (!op) + return -ENOMEM; + + spin_lock_init(&op->bcm_tx_lock); + op->can_id = msg_head->can_id; + op->cfsiz = CFSIZ(msg_head->flags); + op->flags = msg_head->flags; + op->nframes = msg_head->nframes; + + if (op->flags & SETTIMER) + op->count = msg_head->count; + + /* create array for CAN frames and copy the data */ + if (msg_head->nframes > 1) { + op->frames = kmalloc_array(msg_head->nframes, + op->cfsiz, + GFP_KERNEL); + if (!op->frames) { + kfree(op); + return -ENOMEM; + } + } else + op->frames = &op->sframe; + + for (i = 0; i < msg_head->nframes; i++) { + + cf = op->frames + op->cfsiz * i; + err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz); + if (err < 0) + goto free_op; + + if (op->flags & CAN_FD_FRAME) { + if (cf->len > 64) + err = -EINVAL; + } else { + if (cf->len > 8) + err = -EINVAL; + } + + if (err < 0) + goto free_op; + + if (msg_head->flags & TX_CP_CAN_ID) { + /* copy can_id into frame */ + cf->can_id = msg_head->can_id; + } + } + + /* tx_ops never compare with previous received messages */ + op->last_frames = NULL; + + /* bcm_can_tx / bcm_tx_timeout_handler needs this */ + op->sk = sk; + sock_hold(sk); + op->ifindex = ifindex; + + /* initialize uninitialized (kzalloc) structure */ + hrtimer_setup(&op->timer, bcm_tx_timeout_handler, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_SOFT); + + /* currently unused in tx_ops */ + hrtimer_setup(&op->thrtimer, hrtimer_dummy_timeout, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_SOFT); + + add_op_to_list = true; + + } /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */ + + if (op->flags & SETTIMER) { + /* set timer values */ + spin_lock_bh(&op->bcm_tx_lock); + op->ival1 = msg_head->ival1; + op->ival2 = msg_head->ival2; + op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); + op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + spin_unlock_bh(&op->bcm_tx_lock); + + /* disable an active timer due to zero values? */ + if (!op->kt_ival1 && !op->kt_ival2) + hrtimer_cancel(&op->timer); + } + + if (op->flags & STARTTIMER) { + hrtimer_cancel(&op->timer); + /* spec: send CAN frame when starting timer */ + op->flags |= TX_ANNOUNCE; + } + + /* add this bcm_op to the list of the tx_ops? */ + if (add_op_to_list) + list_add_rcu(&op->list, &bo->tx_ops); + + if (op->flags & TX_ANNOUNCE) + bcm_can_tx(op, NULL); + + if (op->flags & STARTTIMER) + bcm_tx_start_timer(op); + + return msg_head->nframes * op->cfsiz + MHSIZ; + +free_op: + if (op->frames != &op->sframe) + kfree(op->frames); + kfree(op); + return err; +} + +static int bcm_rx_setup_rtr_check(struct bcm_msg_head *msg_head, + struct bcm_op *op, void *new_frames) +{ + struct canfd_frame *frame0 = new_frames; + + if (!(msg_head->flags & RX_RTR_FRAME)) + return 0; + + /* this frame is sent out as-is by bcm_can_tx() whenever a matching + * remote request is received, so validate its length the same way + * bcm_tx_setup() validates TX_SETUP frames before installing it + */ + if (msg_head->flags & CAN_FD_FRAME) { + if (frame0->len > 64) + return -EINVAL; + } else { + if (frame0->len > 8) + return -EINVAL; + } + + /* funny feature in RX(!)_SETUP only for RTR-mode: + * copy can_id into frame BUT without RTR-flag to + * prevent a full-load-loopback-test ... ;-] + * normalize this on the staged buffer, before it is + * ever installed into op->frames. + */ + if ((msg_head->flags & TX_CP_CAN_ID) || + frame0->can_id == op->can_id) + frame0->can_id = op->can_id & ~CAN_RTR_FLAG; + + return 0; +} + +/* + * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg) + */ +static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, + int ifindex, struct sock *sk) +{ + struct bcm_sock *bo = bcm_sk(sk); + struct bcm_op *op; + int do_rx_register; + int new_op = 0; + int err = 0; + + if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) { + /* be robust against wrong usage ... */ + msg_head->flags |= RX_FILTER_ID; + /* ignore trailing garbage */ + msg_head->nframes = 0; + } + + /* the first element contains the mux-mask => MAX_NFRAMES + 1 */ + if (msg_head->nframes > MAX_NFRAMES + 1) + return -EINVAL; + + if ((msg_head->flags & RX_RTR_FRAME) && + ((msg_head->nframes != 1) || + (!(msg_head->can_id & CAN_RTR_FLAG)))) + return -EINVAL; + + /* check timeval limitations */ + if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head)) + return -EINVAL; + + /* check the given can_id */ + op = bcm_find_op(&bo->rx_ops, msg_head, ifindex); + if (op) { + void *new_frames = NULL; + + /* update existing BCM operation */ + + /* + * Do we need more space for the CAN frames than currently + * allocated? -> This is a _really_ unusual use-case and + * therefore (complexity / locking) it is not supported. + */ + if (msg_head->nframes > op->nframes) + return -E2BIG; + + if (msg_head->nframes) { + /* get new CAN frames content before locking */ + new_frames = kmalloc(msg_head->nframes * op->cfsiz, + GFP_KERNEL); + if (!new_frames) + return -ENOMEM; + + err = memcpy_from_msg(new_frames, msg, + msg_head->nframes * op->cfsiz); + if (err < 0) { + kfree(new_frames); + return err; + } + + err = bcm_rx_setup_rtr_check(msg_head, op, new_frames); + if (err < 0) { + kfree(new_frames); + return err; + } + } + + spin_lock_bh(&op->bcm_rx_update_lock); + op->nframes = msg_head->nframes; + op->flags = msg_head->flags; + + if (msg_head->nframes) { + /* update CAN frames content */ + memcpy(op->frames, new_frames, + msg_head->nframes * op->cfsiz); + + /* clear last_frames to indicate 'nothing received' */ + memset(op->last_frames, 0, + msg_head->nframes * op->cfsiz); + } + + if (msg_head->flags & SETTIMER) { + op->ival1 = msg_head->ival1; + op->ival2 = msg_head->ival2; + op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); + op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + op->kt_lastmsg = 0; + op->if_detected = 0; /* reclaim ifindex in ANYDEV mode */ + } + spin_unlock_bh(&op->bcm_rx_update_lock); + + /* free temporary frames / kfree(NULL) is safe */ + kfree(new_frames); + + /* Don't register a new CAN filter for the rx_op update unless + * a concurrent NETDEV_UNREGISTER notifier already tore down + * the previous registration. In this case the receiver needs + * to be re-registered here so that this update doesn't + * silently stop delivering frames for the given ifindex. + * Ops with ifindex = 0 (all CAN interfaces) never carry a + * tracked rx_reg_dev and stay registered as-is. + */ + do_rx_register = (ifindex && !op->rx_reg_dev) ? 1 : 0; + + } else { + /* insert new BCM operation for the given can_id */ + op = kzalloc(OPSIZ, GFP_KERNEL); + if (!op) + return -ENOMEM; + + spin_lock_init(&op->bcm_tx_lock); + spin_lock_init(&op->bcm_rx_update_lock); + op->can_id = msg_head->can_id; + op->nframes = msg_head->nframes; + op->cfsiz = CFSIZ(msg_head->flags); + op->flags = msg_head->flags; + + if (msg_head->nframes > 1) { + /* create array for CAN frames and copy the data */ + op->frames = kmalloc_array(msg_head->nframes, + op->cfsiz, + GFP_KERNEL); + if (!op->frames) { + kfree(op); + return -ENOMEM; + } + + /* create and init array for received CAN frames */ + op->last_frames = kcalloc(msg_head->nframes, + op->cfsiz, + GFP_KERNEL); + if (!op->last_frames) { + kfree(op->frames); + kfree(op); + return -ENOMEM; + } + + } else { + op->frames = &op->sframe; + op->last_frames = &op->last_sframe; + } + + if (msg_head->nframes) { + err = memcpy_from_msg(op->frames, msg, + msg_head->nframes * op->cfsiz); + if (err < 0) + goto free_op; + + err = bcm_rx_setup_rtr_check(msg_head, op, op->frames); + if (err < 0) + goto free_op; + } + + /* bcm_can_tx / bcm_tx_timeout_handler needs this */ + op->sk = sk; + sock_hold(sk); + op->ifindex = ifindex; + + /* ifindex for timeout events w/o previous frame reception */ + op->rx_ifindex = ifindex; + + /* initialize uninitialized (kzalloc) structure */ + hrtimer_setup(&op->timer, bcm_rx_timeout_handler, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_SOFT); + hrtimer_setup(&op->thrtimer, bcm_rx_thr_handler, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_SOFT); + + /* call can_rx_register() */ + do_rx_register = 1; + new_op = 1; + + } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */ + + /* check flags */ + + if (op->flags & RX_RTR_FRAME) { + /* no timers in RTR-mode */ + hrtimer_cancel(&op->thrtimer); + hrtimer_cancel(&op->timer); + } else { + if (op->flags & SETTIMER) { + + /* set timers (locked) for newly created op */ + if (new_op) { + spin_lock_bh(&op->bcm_rx_update_lock); + op->ival1 = msg_head->ival1; + op->ival2 = msg_head->ival2; + op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); + op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); + op->kt_lastmsg = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + } + + /* disable an active timer due to zero value? */ + if (!op->kt_ival1) + hrtimer_cancel(&op->timer); + + /* + * In any case cancel the throttle timer, flush + * potentially blocked msgs and reset throttle handling + */ + hrtimer_cancel(&op->thrtimer); + + spin_lock_bh(&op->bcm_rx_update_lock); + bcm_rx_thr_flush(op); + spin_unlock_bh(&op->bcm_rx_update_lock); + } + + if ((op->flags & STARTTIMER) && op->kt_ival1) + hrtimer_start(&op->timer, op->kt_ival1, + HRTIMER_MODE_REL_SOFT); + } + + /* now we can register for can_ids, if we added a new bcm_op + * or need to re-register after a NETDEV_UNREGISTER tore down + * the previous registration of an existing op + */ + if (do_rx_register) { + if (ifindex) { + struct net_device *dev; + + dev = dev_get_by_index(sock_net(sk), ifindex); + if (dev) { + err = can_rx_register(sock_net(sk), dev, + op->can_id, + REGMASK(op->can_id), + bcm_rx_handler, op, + "bcm", sk); + + /* keep a tracked reference so that a later + * unregister can safely reach the device even + * if a concurrent NETDEV_UNREGISTER has + * already unlisted it by ifindex + */ + if (!err) { + op->rx_reg_dev = dev; + netdev_hold(dev, + &op->rx_reg_dev_tracker, + GFP_KERNEL); + } + dev_put(dev); + } else { + /* the requested device is gone - do not + * silently succeed without registering + */ + err = -ENODEV; + } + + } else { + err = can_rx_register(sock_net(sk), NULL, op->can_id, + REGMASK(op->can_id), + bcm_rx_handler, op, "bcm", sk); + } + + if (err) { + /* newly created bcm rx op is broken -> remove it */ + if (new_op) { + bcm_remove_op(op); + return err; + } + + /* an existing op just stays unregistered. + * Cancel op->timer and (defensively) op->thrtimer. + * Other settings can't be reached until the next + * successful RX_SETUP. + */ + hrtimer_cancel(&op->timer); + hrtimer_cancel(&op->thrtimer); + return err; + } + + /* add a new bcm_op to the list of the rx_ops */ + if (new_op) + list_add_rcu(&op->list, &bo->rx_ops); + } + + return msg_head->nframes * op->cfsiz + MHSIZ; + +free_op: + if (op->frames != &op->sframe) + kfree(op->frames); + if (op->last_frames != &op->last_sframe) + kfree(op->last_frames); + kfree(op); + return err; +} + +/* + * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg) + */ +static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk, + int cfsiz) +{ + struct sk_buff *skb; + struct can_skb_ext *csx; + struct net_device *dev; + int err; + + /* we need a real device to send frames */ + if (!ifindex) + return -ENODEV; + + skb = alloc_skb(cfsiz, GFP_KERNEL); + if (!skb) + return -ENOMEM; + + csx = can_skb_ext_add(skb); + if (!csx) { + kfree_skb(skb); + return -ENOMEM; + } + + err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz); + if (err < 0) { + kfree_skb(skb); + return err; + } + + dev = dev_get_by_index(sock_net(sk), ifindex); + if (!dev) { + kfree_skb(skb); + return -ENODEV; + } + + csx->can_iif = dev->ifindex; + skb->dev = dev; + can_skb_set_owner(skb, sk); + err = can_send(skb, 1); /* send with loopback */ + dev_put(dev); + + if (err) + return err; + + return cfsiz + MHSIZ; +} + +/* + * bcm_sendmsg - process BCM commands (opcodes) from the userspace + */ +static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) +{ + struct sock *sk = sock->sk; + struct bcm_sock *bo = bcm_sk(sk); + int ifindex; + struct bcm_msg_head msg_head; + int cfsiz; + int ret; /* read bytes or error codes as return value */ + + /* Lockless fast-path check for bound socket */ + if (!READ_ONCE(bo->bound)) + return -ENOTCONN; + + /* check for valid message length from userspace */ + if (size < MHSIZ) + return -EINVAL; + + /* read message head information */ + ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ); + if (ret < 0) + return ret; + + cfsiz = CFSIZ(msg_head.flags); + if ((size - MHSIZ) % cfsiz) + return -EINVAL; + + lock_sock(sk); + + /* Re-validate under the socket lock: a concurrent bcm_notify() + * may have unbound this socket (device removal) after the + * lockless fast-path check above. bo->ifindex is only ever + * mutated under lock_sock(), so reading it here - instead of + * before taking the lock - guarantees it can't be observed + * torn against bo->bound. + */ + if (!bo->bound) { + ret = -ENOTCONN; + goto out_release; + } + + /* default ifindex for this bcm_op */ + ifindex = bo->ifindex; + + /* check for alternative ifindex for this bcm_op */ + + if (!ifindex && msg->msg_name) { + /* no bound device as default => check msg_name */ + DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name); + + if (msg->msg_namelen < BCM_MIN_NAMELEN) { + ret = -EINVAL; + goto out_release; + } + + if (addr->can_family != AF_CAN) { + ret = -EINVAL; + goto out_release; + } + + /* ifindex from sendto() */ + ifindex = addr->can_ifindex; + + if (ifindex) { + struct net_device *dev; + + dev = dev_get_by_index(sock_net(sk), ifindex); + if (!dev) { + ret = -ENODEV; + goto out_release; + } + + if (dev->type != ARPHRD_CAN) { + dev_put(dev); + ret = -ENODEV; + goto out_release; + } + + dev_put(dev); + } + } + + switch (msg_head.opcode) { + + case TX_SETUP: + ret = bcm_tx_setup(&msg_head, msg, ifindex, sk); + break; + + case RX_SETUP: + ret = bcm_rx_setup(&msg_head, msg, ifindex, sk); + break; + + case TX_DELETE: + if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex)) + ret = MHSIZ; + else + ret = -EINVAL; + break; + + case RX_DELETE: + if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex)) + ret = MHSIZ; + else + ret = -EINVAL; + break; + + case TX_READ: + /* reuse msg_head for the reply to TX_READ */ + msg_head.opcode = TX_STATUS; + ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex); + break; + + case RX_READ: + /* reuse msg_head for the reply to RX_READ */ + msg_head.opcode = RX_STATUS; + ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex); + break; + + case TX_SEND: + /* we need exactly one CAN frame behind the msg head */ + if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ)) + ret = -EINVAL; + else + ret = bcm_tx_send(msg, ifindex, sk, cfsiz); + break; + + default: + ret = -EINVAL; + break; + } + +out_release: + release_sock(sk); + + return ret; +} + +/* + * notification handler for netdevice status changes + */ +static void bcm_notify(struct bcm_sock *bo, unsigned long msg, + struct net_device *dev) +{ + struct sock *sk = &bo->sk; + struct bcm_op *op; + int notify_enodev = 0; + + if (!net_eq(dev_net(dev), sock_net(sk))) + return; + + switch (msg) { + + case NETDEV_UNREGISTER: + lock_sock(sk); + + /* rx_ops: remove device specific receive entries */ + list_for_each_entry(op, &bo->rx_ops, list) { + if (op->rx_reg_dev == dev) + bcm_rx_unreg(dev, op); + + /* release an ANYDEV op's claim (see bcm_rx_handler()) + * on this now confirmed-gone interface. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + if (op->if_detected == dev->ifindex) + op->if_detected = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + } + } + + /* tx_ops: stop device specific cyclic transmissions on the + * vanishing ifindex. Cancelling the timer is enough to stop + * cyclic bcm_can_tx() calls as there is no re-arming. + */ + list_for_each_entry(op, &bo->tx_ops, list) + if (op->ifindex == dev->ifindex) + hrtimer_cancel(&op->timer); + + /* remove device reference, if this is our bound device */ + if (bo->bound && bo->ifindex == dev->ifindex) { +#if IS_ENABLED(CONFIG_PROC_FS) + if (sock_net(sk)->can.bcmproc_dir && bo->bcm_proc_read) { + remove_proc_entry(bo->procname, sock_net(sk)->can.bcmproc_dir); + bo->bcm_proc_read = NULL; + } +#endif + /* Paired with the lockless fast-path check in + * bcm_sendmsg(); bo->ifindex itself is only ever + * accessed under lock_sock() so it needs no + * annotation. + */ + WRITE_ONCE(bo->bound, 0); + bo->ifindex = 0; + notify_enodev = 1; + } + + release_sock(sk); + + if (notify_enodev) { + sk->sk_err = ENODEV; + if (!sock_flag(sk, SOCK_DEAD)) + sk_error_report(sk); + } + break; + + case NETDEV_DOWN: + if (bo->bound && bo->ifindex == dev->ifindex) { + sk->sk_err = ENETDOWN; + if (!sock_flag(sk, SOCK_DEAD)) + sk_error_report(sk); + } + } +} + +static int bcm_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; + if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN) + return NOTIFY_DONE; + if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */ + return NOTIFY_DONE; + + spin_lock(&bcm_notifier_lock); + list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) { + spin_unlock(&bcm_notifier_lock); + bcm_notify(bcm_busy_notifier, msg, dev); + spin_lock(&bcm_notifier_lock); + } + bcm_busy_notifier = NULL; + spin_unlock(&bcm_notifier_lock); + return NOTIFY_DONE; +} + +/* + * initial settings for all BCM sockets to be set at socket creation time + */ +static int bcm_init(struct sock *sk) +{ + struct bcm_sock *bo = bcm_sk(sk); + + bo->bound = 0; + bo->ifindex = 0; + bo->dropped_usr_msgs = 0; + bo->bcm_proc_read = NULL; + + INIT_LIST_HEAD(&bo->tx_ops); + INIT_LIST_HEAD(&bo->rx_ops); + + /* set notifier */ + spin_lock(&bcm_notifier_lock); + list_add_tail(&bo->notifier, &bcm_notifier_list); + spin_unlock(&bcm_notifier_lock); + + return 0; +} + +/* + * standard socket functions + */ +static int bcm_release(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct net *net; + struct bcm_sock *bo; + struct bcm_op *op, *next; + + if (!sk) + return 0; + + net = sock_net(sk); + bo = bcm_sk(sk); + + /* remove bcm_ops, timer, rx_unregister(), etc. */ + + spin_lock(&bcm_notifier_lock); + while (bcm_busy_notifier == bo) { + spin_unlock(&bcm_notifier_lock); + schedule_timeout_uninterruptible(1); + spin_lock(&bcm_notifier_lock); + } + list_del(&bo->notifier); + spin_unlock(&bcm_notifier_lock); + + lock_sock(sk); + +#if IS_ENABLED(CONFIG_PROC_FS) + /* remove procfs entry */ + if (net->can.bcmproc_dir && bo->bcm_proc_read) + remove_proc_entry(bo->procname, net->can.bcmproc_dir); +#endif /* CONFIG_PROC_FS */ + + list_for_each_entry_safe(op, next, &bo->tx_ops, list) { + list_del_rcu(&op->list); + bcm_remove_op(op); + } + + list_for_each_entry_safe(op, next, &bo->rx_ops, list) { + /* + * Don't care if we're bound or not (due to netdev problems) + * can_rx_unregister() is always a save thing to do here. + */ + if (op->ifindex) { + /* + * Only remove subscriptions that had not + * been removed due to NETDEV_UNREGISTER + * in bcm_notifier() + * + * op->rx_reg_dev is a tracked reference taken + * when the subscription was registered, so it + * stays valid here even if a concurrent + * NETDEV_UNREGISTER already unlisted the device. + */ + if (op->rx_reg_dev) + bcm_rx_unreg(op->rx_reg_dev, op); + } else + can_rx_unregister(net, NULL, op->can_id, + REGMASK(op->can_id), + bcm_rx_handler, op); + + } + + synchronize_rcu(); + + list_for_each_entry_safe(op, next, &bo->rx_ops, list) { + list_del_rcu(&op->list); + bcm_remove_op(op); + } + + /* remove device reference */ + if (bo->bound) { + WRITE_ONCE(bo->bound, 0); + bo->ifindex = 0; + } + + sock_orphan(sk); + sock->sk = NULL; + + release_sock(sk); + sock_prot_inuse_add(net, sk->sk_prot, -1); + sock_put(sk); + + return 0; +} + +static int bcm_connect(struct socket *sock, struct sockaddr_unsized *uaddr, int len, + int flags) +{ + struct sockaddr_can *addr = (struct sockaddr_can *)uaddr; + struct sock *sk = sock->sk; + struct bcm_sock *bo = bcm_sk(sk); + struct net *net = sock_net(sk); + int ret = 0; + + if (len < BCM_MIN_NAMELEN) + return -EINVAL; + + lock_sock(sk); + + if (bo->bound) { + ret = -EISCONN; + goto fail; + } + + /* bind a device to this socket */ + if (addr->can_ifindex) { + struct net_device *dev; + + dev = dev_get_by_index(net, addr->can_ifindex); + if (!dev) { + ret = -ENODEV; + goto fail; + } + if (dev->type != ARPHRD_CAN) { + dev_put(dev); + ret = -ENODEV; + goto fail; + } + + bo->ifindex = dev->ifindex; + dev_put(dev); + + } else { + /* no interface reference for ifindex = 0 ('any' CAN device) */ + bo->ifindex = 0; + } + +#if IS_ENABLED(CONFIG_PROC_FS) + if (net->can.bcmproc_dir) { + /* unique socket address as filename */ + sprintf(bo->procname, "%llu", sock_i_ino(sk)); + bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644, + net->can.bcmproc_dir, + bcm_proc_show, sk); + if (!bo->bcm_proc_read) { + ret = -ENOMEM; + goto fail; + } + } +#endif /* CONFIG_PROC_FS */ + + /* bo->ifindex above is fully assigned before this point; pairs + * with the lockless fast-path check in bcm_sendmsg() + */ + WRITE_ONCE(bo->bound, 1); + +fail: + release_sock(sk); + + return ret; +} + +static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, + int flags) +{ + struct sock *sk = sock->sk; + struct sk_buff *skb; + int error = 0; + int err; + + skb = skb_recv_datagram(sk, flags, &error); + if (!skb) + return error; + + if (skb->len < size) + size = skb->len; + + err = memcpy_to_msg(msg, skb->data, size); + if (err < 0) { + skb_free_datagram(sk, skb); + return err; + } + + sock_recv_cmsgs(msg, sk, skb); + + if (msg->msg_name) { + __sockaddr_check_size(BCM_MIN_NAMELEN); + msg->msg_namelen = BCM_MIN_NAMELEN; + memcpy(msg->msg_name, skb->cb, msg->msg_namelen); + } + + /* assign the flags that have been recorded in bcm_send_to_user() */ + msg->msg_flags |= *(bcm_flags(skb)); + + skb_free_datagram(sk, skb); + + return size; +} + +static int bcm_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 bcm_ops = { + .family = PF_CAN, + .release = bcm_release, + .bind = sock_no_bind, + .connect = bcm_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = sock_no_getname, + .poll = datagram_poll, + .ioctl = bcm_sock_no_ioctlcmd, + .gettstamp = sock_gettstamp, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .sendmsg = bcm_sendmsg, + .recvmsg = bcm_recvmsg, + .mmap = sock_no_mmap, +}; + +static struct proto bcm_proto __read_mostly = { + .name = "CAN_BCM", + .owner = THIS_MODULE, + .obj_size = sizeof(struct bcm_sock), + .init = bcm_init, +}; + +static const struct can_proto bcm_can_proto = { + .type = SOCK_DGRAM, + .protocol = CAN_BCM, + .ops = &bcm_ops, + .prot = &bcm_proto, +}; + +static int canbcm_pernet_init(struct net *net) +{ +#if IS_ENABLED(CONFIG_PROC_FS) + /* create /proc/net/can-bcm directory */ + net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net); +#endif /* CONFIG_PROC_FS */ + + return 0; +} + +static void canbcm_pernet_exit(struct net *net) +{ +#if IS_ENABLED(CONFIG_PROC_FS) + /* remove /proc/net/can-bcm directory */ + if (net->can.bcmproc_dir) + remove_proc_entry("can-bcm", net->proc_net); +#endif /* CONFIG_PROC_FS */ +} + +static struct pernet_operations canbcm_pernet_ops __read_mostly = { + .init = canbcm_pernet_init, + .exit = canbcm_pernet_exit, +}; + +static struct notifier_block canbcm_notifier = { + .notifier_call = bcm_notifier +}; + +static int __init bcm_module_init(void) +{ + int err; + + bcm_wq = alloc_workqueue("can-bcm-wq", WQ_UNBOUND, 0); + if (!bcm_wq) + return -ENOMEM; + + pr_info("can: broadcast manager protocol\n"); + + err = register_pernet_subsys(&canbcm_pernet_ops); + if (err) + goto register_pernet_failed; + + err = register_netdevice_notifier(&canbcm_notifier); + if (err) + goto register_notifier_failed; + + err = can_proto_register(&bcm_can_proto); + if (err < 0) { + printk(KERN_ERR "can: registration of bcm protocol failed\n"); + goto register_proto_failed; + } + + return 0; + +register_proto_failed: + unregister_netdevice_notifier(&canbcm_notifier); +register_notifier_failed: + unregister_pernet_subsys(&canbcm_pernet_ops); +register_pernet_failed: + destroy_workqueue(bcm_wq); + return err; +} + +static void __exit bcm_module_exit(void) +{ + can_proto_unregister(&bcm_can_proto); + unregister_netdevice_notifier(&canbcm_notifier); + unregister_pernet_subsys(&canbcm_pernet_ops); + rcu_barrier(); + destroy_workqueue(bcm_wq); +} + +module_init(bcm_module_init); +module_exit(bcm_module_exit); |