obj-$(CONFIG_CAN_VCAN) += vcan.o
obj-$(CONFIG_CAN_VXCAN) += vxcan.o
-obj-$(CONFIG_CAN_SLCAN) += slcan.o
+obj-$(CONFIG_CAN_SLCAN) += slcan/
obj-y += dev/
obj-y += rcar/
+++ /dev/null
-/*
- * slcan.c - serial line CAN interface driver (using tty line discipline)
- *
- * This file is derived from linux/drivers/net/slip/slip.c
- *
- * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
- * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
- * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, see http://www.gnu.org/licenses/gpl.html
- *
- * 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/moduleparam.h>
-
-#include <linux/uaccess.h>
-#include <linux/bitops.h>
-#include <linux/string.h>
-#include <linux/tty.h>
-#include <linux/errno.h>
-#include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <linux/rtnetlink.h>
-#include <linux/if_arp.h>
-#include <linux/if_ether.h>
-#include <linux/sched.h>
-#include <linux/delay.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/workqueue.h>
-#include <linux/can.h>
-#include <linux/can/dev.h>
-#include <linux/can/skb.h>
-
-MODULE_ALIAS_LDISC(N_SLCAN);
-MODULE_DESCRIPTION("serial line CAN interface");
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
-
-#define SLCAN_MAGIC 0x53CA
-
-static int maxdev = 10; /* MAX number of SLCAN channels;
- This can be overridden with
- insmod slcan.ko maxdev=nnn */
-module_param(maxdev, int, 0);
-MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
-
-/* maximum rx buffer len: extended CAN frame with timestamp */
-#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
-
-#define SLC_CMD_LEN 1
-#define SLC_SFF_ID_LEN 3
-#define SLC_EFF_ID_LEN 8
-
-struct slcan {
- struct can_priv can;
- int magic;
-
- /* Various fields. */
- struct tty_struct *tty; /* ptr to TTY structure */
- struct net_device *dev; /* easy for intr handling */
- spinlock_t lock;
- struct work_struct tx_work; /* Flushes transmit buffer */
-
- /* These are pointers to the malloc()ed frame buffers. */
- unsigned char rbuff[SLC_MTU]; /* receiver buffer */
- int rcount; /* received chars counter */
- unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
- unsigned char *xhead; /* pointer to next XMIT byte */
- int xleft; /* bytes left in XMIT queue */
-
- unsigned long flags; /* Flag values/ mode etc */
-#define SLF_INUSE 0 /* Channel in use */
-#define SLF_ERROR 1 /* Parity, etc. error */
-#define SLF_XCMD 2 /* Command transmission */
- wait_queue_head_t xcmd_wait; /* Wait queue for commands */
- /* transmission */
-};
-
-static struct net_device **slcan_devs;
-
-static const u32 slcan_bitrate_const[] = {
- 10000, 20000, 50000, 100000, 125000,
- 250000, 500000, 800000, 1000000
-};
-
- /************************************************************************
- * SLCAN ENCAPSULATION FORMAT *
- ************************************************************************/
-
-/*
- * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
- * frame format) a data length code (len) which can be from 0 to 8
- * and up to <len> data bytes as payload.
- * Additionally a CAN frame may become a remote transmission frame if the
- * RTR-bit is set. This causes another ECU to send a CAN frame with the
- * given can_id.
- *
- * The SLCAN ASCII representation of these different frame types is:
- * <type> <id> <dlc> <data>*
- *
- * Extended frames (29 bit) are defined by capital characters in the type.
- * RTR frames are defined as 'r' types - normal frames have 't' type:
- * t => 11 bit data frame
- * r => 11 bit RTR frame
- * T => 29 bit data frame
- * R => 29 bit RTR frame
- *
- * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
- * The <dlc> is a one byte ASCII number ('0' - '8')
- * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
- *
- * Examples:
- *
- * t1230 : can_id 0x123, len 0, no data
- * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33
- * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55
- * r1230 : can_id 0x123, len 0, no data, remote transmission request
- *
- */
-
- /************************************************************************
- * STANDARD SLCAN DECAPSULATION *
- ************************************************************************/
-
-/* Send one completely decapsulated can_frame to the network layer */
-static void slc_bump(struct slcan *sl)
-{
- struct sk_buff *skb;
- struct can_frame *cf;
- int i, tmp;
- u32 tmpid;
- char *cmd = sl->rbuff;
-
- skb = alloc_can_skb(sl->dev, &cf);
- if (unlikely(!skb)) {
- sl->dev->stats.rx_dropped++;
- return;
- }
-
- switch (*cmd) {
- case 'r':
- cf->can_id = CAN_RTR_FLAG;
- fallthrough;
- case 't':
- /* store dlc ASCII value and terminate SFF CAN ID string */
- cf->len = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
- sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;
- /* point to payload data behind the dlc */
- cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;
- break;
- case 'R':
- cf->can_id = CAN_RTR_FLAG;
- fallthrough;
- case 'T':
- cf->can_id |= CAN_EFF_FLAG;
- /* store dlc ASCII value and terminate EFF CAN ID string */
- cf->len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
- sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;
- /* point to payload data behind the dlc */
- cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;
- break;
- default:
- goto decode_failed;
- }
-
- if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))
- goto decode_failed;
-
- cf->can_id |= tmpid;
-
- /* get len from sanitized ASCII value */
- if (cf->len >= '0' && cf->len < '9')
- cf->len -= '0';
- else
- goto decode_failed;
-
- /* RTR frames may have a dlc > 0 but they never have any data bytes */
- if (!(cf->can_id & CAN_RTR_FLAG)) {
- for (i = 0; i < cf->len; i++) {
- tmp = hex_to_bin(*cmd++);
- if (tmp < 0)
- goto decode_failed;
-
- cf->data[i] = (tmp << 4);
- tmp = hex_to_bin(*cmd++);
- if (tmp < 0)
- goto decode_failed;
-
- cf->data[i] |= tmp;
- }
- }
-
- sl->dev->stats.rx_packets++;
- if (!(cf->can_id & CAN_RTR_FLAG))
- sl->dev->stats.rx_bytes += cf->len;
-
- netif_rx(skb);
- return;
-
-decode_failed:
- sl->dev->stats.rx_errors++;
- dev_kfree_skb(skb);
-}
-
-/* parse tty input stream */
-static void slcan_unesc(struct slcan *sl, unsigned char s)
-{
- if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
- if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
- (sl->rcount > 4)) {
- slc_bump(sl);
- }
- sl->rcount = 0;
- } else {
- if (!test_bit(SLF_ERROR, &sl->flags)) {
- if (sl->rcount < SLC_MTU) {
- sl->rbuff[sl->rcount++] = s;
- return;
- } else {
- sl->dev->stats.rx_over_errors++;
- set_bit(SLF_ERROR, &sl->flags);
- }
- }
- }
-}
-
- /************************************************************************
- * STANDARD SLCAN ENCAPSULATION *
- ************************************************************************/
-
-/* Encapsulate one can_frame and stuff into a TTY queue. */
-static void slc_encaps(struct slcan *sl, struct can_frame *cf)
-{
- int actual, i;
- unsigned char *pos;
- unsigned char *endpos;
- canid_t id = cf->can_id;
-
- pos = sl->xbuff;
-
- if (cf->can_id & CAN_RTR_FLAG)
- *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
- else
- *pos = 'T'; /* becomes 't' in standard frame format (SSF) */
-
- /* determine number of chars for the CAN-identifier */
- if (cf->can_id & CAN_EFF_FLAG) {
- id &= CAN_EFF_MASK;
- endpos = pos + SLC_EFF_ID_LEN;
- } else {
- *pos |= 0x20; /* convert R/T to lower case for SFF */
- id &= CAN_SFF_MASK;
- endpos = pos + SLC_SFF_ID_LEN;
- }
-
- /* build 3 (SFF) or 8 (EFF) digit CAN identifier */
- pos++;
- while (endpos >= pos) {
- *endpos-- = hex_asc_upper[id & 0xf];
- id >>= 4;
- }
-
- pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
-
- *pos++ = cf->len + '0';
-
- /* RTR frames may have a dlc > 0 but they never have any data bytes */
- if (!(cf->can_id & CAN_RTR_FLAG)) {
- for (i = 0; i < cf->len; i++)
- pos = hex_byte_pack_upper(pos, cf->data[i]);
-
- sl->dev->stats.tx_bytes += cf->len;
- }
-
- *pos++ = '\r';
-
- /* Order of next two lines is *very* important.
- * When we are sending a little amount of data,
- * the transfer may be completed inside the ops->write()
- * routine, because it's running with interrupts enabled.
- * In this case we *never* got WRITE_WAKEUP event,
- * if we did not request it before write operation.
- * 14 Oct 1994 Dmitry Gorodchanin.
- */
- set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
- actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
- sl->xleft = (pos - sl->xbuff) - actual;
- sl->xhead = sl->xbuff + actual;
-}
-
-/* Write out any remaining transmit buffer. Scheduled when tty is writable */
-static void slcan_transmit(struct work_struct *work)
-{
- struct slcan *sl = container_of(work, struct slcan, tx_work);
- int actual;
-
- spin_lock_bh(&sl->lock);
- /* First make sure we're connected. */
- if (!sl->tty || sl->magic != SLCAN_MAGIC ||
- (unlikely(!netif_running(sl->dev)) &&
- likely(!test_bit(SLF_XCMD, &sl->flags)))) {
- spin_unlock_bh(&sl->lock);
- return;
- }
-
- if (sl->xleft <= 0) {
- if (unlikely(test_bit(SLF_XCMD, &sl->flags))) {
- clear_bit(SLF_XCMD, &sl->flags);
- clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
- spin_unlock_bh(&sl->lock);
- wake_up(&sl->xcmd_wait);
- return;
- }
-
- /* Now serial buffer is almost free & we can start
- * transmission of another packet */
- sl->dev->stats.tx_packets++;
- clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
- spin_unlock_bh(&sl->lock);
- netif_wake_queue(sl->dev);
- return;
- }
-
- actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
- sl->xleft -= actual;
- sl->xhead += actual;
- spin_unlock_bh(&sl->lock);
-}
-
-/*
- * Called by the driver when there's room for more data.
- * Schedule the transmit.
- */
-static void slcan_write_wakeup(struct tty_struct *tty)
-{
- struct slcan *sl;
-
- rcu_read_lock();
- sl = rcu_dereference(tty->disc_data);
- if (sl)
- schedule_work(&sl->tx_work);
- rcu_read_unlock();
-}
-
-/* Send a can_frame to a TTY queue. */
-static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
-{
- struct slcan *sl = netdev_priv(dev);
-
- if (can_dropped_invalid_skb(dev, skb))
- return NETDEV_TX_OK;
-
- spin_lock(&sl->lock);
- if (!netif_running(dev)) {
- spin_unlock(&sl->lock);
- netdev_warn(dev, "xmit: iface is down\n");
- goto out;
- }
- if (sl->tty == NULL) {
- spin_unlock(&sl->lock);
- goto out;
- }
-
- netif_stop_queue(sl->dev);
- slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
- spin_unlock(&sl->lock);
-
-out:
- kfree_skb(skb);
- return NETDEV_TX_OK;
-}
-
-
-/******************************************
- * Routines looking at netdevice side.
- ******************************************/
-
-static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd)
-{
- int ret, actual, n;
-
- spin_lock(&sl->lock);
- if (!sl->tty) {
- spin_unlock(&sl->lock);
- return -ENODEV;
- }
-
- n = snprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd);
- set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
- actual = sl->tty->ops->write(sl->tty, sl->xbuff, n);
- sl->xleft = n - actual;
- sl->xhead = sl->xbuff + actual;
- set_bit(SLF_XCMD, &sl->flags);
- spin_unlock(&sl->lock);
- ret = wait_event_interruptible_timeout(sl->xcmd_wait,
- !test_bit(SLF_XCMD, &sl->flags),
- HZ);
- clear_bit(SLF_XCMD, &sl->flags);
- if (ret == -ERESTARTSYS)
- return ret;
-
- if (ret == 0)
- return -ETIMEDOUT;
-
- return 0;
-}
-
-/* Netdevice UP -> DOWN routine */
-static int slc_close(struct net_device *dev)
-{
- struct slcan *sl = netdev_priv(dev);
- int err;
-
- spin_lock_bh(&sl->lock);
- if (sl->tty) {
- if (sl->can.bittiming.bitrate &&
- sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
- spin_unlock_bh(&sl->lock);
- err = slcan_transmit_cmd(sl, "C\r");
- spin_lock_bh(&sl->lock);
- if (err)
- netdev_warn(dev,
- "failed to send close command 'C\\r'\n");
- }
-
- /* TTY discipline is running. */
- clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
- }
- netif_stop_queue(dev);
- close_candev(dev);
- sl->can.state = CAN_STATE_STOPPED;
- if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN)
- sl->can.bittiming.bitrate = CAN_BITRATE_UNSET;
-
- sl->rcount = 0;
- sl->xleft = 0;
- spin_unlock_bh(&sl->lock);
-
- return 0;
-}
-
-/* Netdevice DOWN -> UP routine */
-static int slc_open(struct net_device *dev)
-{
- struct slcan *sl = netdev_priv(dev);
- unsigned char cmd[SLC_MTU];
- int err, s;
-
- if (sl->tty == NULL)
- return -ENODEV;
-
- /* The baud rate is not set with the command
- * `ip link set <iface> type can bitrate <baud>' and therefore
- * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing
- * open_candev() to fail. So let's set to a fake value.
- */
- if (sl->can.bittiming.bitrate == CAN_BITRATE_UNSET)
- sl->can.bittiming.bitrate = CAN_BITRATE_UNKNOWN;
-
- err = open_candev(dev);
- if (err) {
- netdev_err(dev, "failed to open can device\n");
- return err;
- }
-
- sl->flags &= BIT(SLF_INUSE);
-
- if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
- for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) {
- if (sl->can.bittiming.bitrate == slcan_bitrate_const[s])
- break;
- }
-
- /* The CAN framework has already validate the bitrate value,
- * so we can avoid to check if `s' has been properly set.
- */
-
- snprintf(cmd, sizeof(cmd), "C\rS%d\r", s);
- err = slcan_transmit_cmd(sl, cmd);
- if (err) {
- netdev_err(dev,
- "failed to send bitrate command 'C\\rS%d\\r'\n",
- s);
- goto cmd_transmit_failed;
- }
-
- err = slcan_transmit_cmd(sl, "O\r");
- if (err) {
- netdev_err(dev, "failed to send open command 'O\\r'\n");
- goto cmd_transmit_failed;
- }
- }
-
- sl->can.state = CAN_STATE_ERROR_ACTIVE;
- netif_start_queue(dev);
- return 0;
-
-cmd_transmit_failed:
- close_candev(dev);
- return err;
-}
-
-static void slc_dealloc(struct slcan *sl)
-{
- int i = sl->dev->base_addr;
-
- free_candev(sl->dev);
- slcan_devs[i] = NULL;
-}
-
-static int slcan_change_mtu(struct net_device *dev, int new_mtu)
-{
- return -EINVAL;
-}
-
-static const struct net_device_ops slc_netdev_ops = {
- .ndo_open = slc_open,
- .ndo_stop = slc_close,
- .ndo_start_xmit = slc_xmit,
- .ndo_change_mtu = slcan_change_mtu,
-};
-
-/******************************************
- Routines looking at TTY side.
- ******************************************/
-
-/*
- * Handle the 'receiver data ready' interrupt.
- * This function is called by the 'tty_io' module in the kernel when
- * a block of SLCAN data has been received, which can now be decapsulated
- * and sent on to some IP layer for further processing. This will not
- * be re-entered while running but other ldisc functions may be called
- * in parallel
- */
-
-static void slcan_receive_buf(struct tty_struct *tty,
- const unsigned char *cp, const char *fp,
- int count)
-{
- struct slcan *sl = (struct slcan *) tty->disc_data;
-
- if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
- return;
-
- /* Read the characters out of the buffer */
- while (count--) {
- if (fp && *fp++) {
- if (!test_and_set_bit(SLF_ERROR, &sl->flags))
- sl->dev->stats.rx_errors++;
- cp++;
- continue;
- }
- slcan_unesc(sl, *cp++);
- }
-}
-
-/************************************
- * slcan_open helper routines.
- ************************************/
-
-/* Collect hanged up channels */
-static void slc_sync(void)
-{
- int i;
- struct net_device *dev;
- struct slcan *sl;
-
- for (i = 0; i < maxdev; i++) {
- dev = slcan_devs[i];
- if (dev == NULL)
- break;
-
- sl = netdev_priv(dev);
- if (sl->tty)
- continue;
- if (dev->flags & IFF_UP)
- dev_close(dev);
- }
-}
-
-/* Find a free SLCAN channel, and link in this `tty' line. */
-static struct slcan *slc_alloc(void)
-{
- int i;
- struct net_device *dev = NULL;
- struct slcan *sl;
-
- for (i = 0; i < maxdev; i++) {
- dev = slcan_devs[i];
- if (dev == NULL)
- break;
-
- }
-
- /* Sorry, too many, all slots in use */
- if (i >= maxdev)
- return NULL;
-
- dev = alloc_candev(sizeof(*sl), 1);
- if (!dev)
- return NULL;
-
- snprintf(dev->name, sizeof(dev->name), "slcan%d", i);
- dev->netdev_ops = &slc_netdev_ops;
- dev->base_addr = i;
- sl = netdev_priv(dev);
-
- /* Initialize channel control data */
- sl->magic = SLCAN_MAGIC;
- sl->dev = dev;
- sl->can.bitrate_const = slcan_bitrate_const;
- sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const);
- spin_lock_init(&sl->lock);
- INIT_WORK(&sl->tx_work, slcan_transmit);
- init_waitqueue_head(&sl->xcmd_wait);
- slcan_devs[i] = dev;
-
- return sl;
-}
-
-/*
- * Open the high-level part of the SLCAN channel.
- * This function is called by the TTY module when the
- * SLCAN line discipline is called for. Because we are
- * sure the tty line exists, we only have to link it to
- * a free SLCAN channel...
- *
- * Called in process context serialized from other ldisc calls.
- */
-
-static int slcan_open(struct tty_struct *tty)
-{
- struct slcan *sl;
- int err;
-
- if (!capable(CAP_NET_ADMIN))
- return -EPERM;
-
- if (tty->ops->write == NULL)
- return -EOPNOTSUPP;
-
- /* RTnetlink lock is misused here to serialize concurrent
- opens of slcan channels. There are better ways, but it is
- the simplest one.
- */
- rtnl_lock();
-
- /* Collect hanged up channels. */
- slc_sync();
-
- sl = tty->disc_data;
-
- err = -EEXIST;
- /* First make sure we're not already connected. */
- if (sl && sl->magic == SLCAN_MAGIC)
- goto err_exit;
-
- /* OK. Find a free SLCAN channel to use. */
- err = -ENFILE;
- sl = slc_alloc();
- if (sl == NULL)
- goto err_exit;
-
- sl->tty = tty;
- tty->disc_data = sl;
-
- if (!test_bit(SLF_INUSE, &sl->flags)) {
- /* Perform the low-level SLCAN initialization. */
- sl->rcount = 0;
- sl->xleft = 0;
-
- set_bit(SLF_INUSE, &sl->flags);
-
- rtnl_unlock();
- err = register_candev(sl->dev);
- if (err) {
- pr_err("slcan: can't register candev\n");
- goto err_free_chan;
- }
- } else {
- rtnl_unlock();
- }
-
- tty->receive_room = 65536; /* We don't flow control */
-
- /* TTY layer expects 0 on success */
- return 0;
-
-err_free_chan:
- rtnl_lock();
- sl->tty = NULL;
- tty->disc_data = NULL;
- clear_bit(SLF_INUSE, &sl->flags);
- slc_dealloc(sl);
- rtnl_unlock();
- return err;
-
-err_exit:
- rtnl_unlock();
-
- /* Count references from TTY module */
- return err;
-}
-
-/*
- * Close down a SLCAN channel.
- * This means flushing out any pending queues, and then returning. This
- * call is serialized against other ldisc functions.
- *
- * We also use this method for a hangup event.
- */
-
-static void slcan_close(struct tty_struct *tty)
-{
- struct slcan *sl = (struct slcan *) tty->disc_data;
-
- /* First make sure we're connected. */
- if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
- return;
-
- spin_lock_bh(&sl->lock);
- rcu_assign_pointer(tty->disc_data, NULL);
- sl->tty = NULL;
- spin_unlock_bh(&sl->lock);
-
- synchronize_rcu();
- flush_work(&sl->tx_work);
-
- slc_close(sl->dev);
- unregister_candev(sl->dev);
- rtnl_lock();
- slc_dealloc(sl);
- rtnl_unlock();
-}
-
-static void slcan_hangup(struct tty_struct *tty)
-{
- slcan_close(tty);
-}
-
-/* Perform I/O control on an active SLCAN channel. */
-static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,
- unsigned long arg)
-{
- struct slcan *sl = (struct slcan *) tty->disc_data;
- unsigned int tmp;
-
- /* First make sure we're connected. */
- if (!sl || sl->magic != SLCAN_MAGIC)
- return -EINVAL;
-
- switch (cmd) {
- case SIOCGIFNAME:
- tmp = strlen(sl->dev->name) + 1;
- if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
- return -EFAULT;
- return 0;
-
- case SIOCSIFHWADDR:
- return -EINVAL;
-
- default:
- return tty_mode_ioctl(tty, cmd, arg);
- }
-}
-
-static struct tty_ldisc_ops slc_ldisc = {
- .owner = THIS_MODULE,
- .num = N_SLCAN,
- .name = "slcan",
- .open = slcan_open,
- .close = slcan_close,
- .hangup = slcan_hangup,
- .ioctl = slcan_ioctl,
- .receive_buf = slcan_receive_buf,
- .write_wakeup = slcan_write_wakeup,
-};
-
-static int __init slcan_init(void)
-{
- int status;
-
- if (maxdev < 4)
- maxdev = 4; /* Sanity */
-
- pr_info("slcan: serial line CAN interface driver\n");
- pr_info("slcan: %d dynamic interface channels.\n", maxdev);
-
- slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);
- if (!slcan_devs)
- return -ENOMEM;
-
- /* Fill in our line protocol discipline, and register it */
- status = tty_register_ldisc(&slc_ldisc);
- if (status) {
- printk(KERN_ERR "slcan: can't register line discipline\n");
- kfree(slcan_devs);
- }
- return status;
-}
-
-static void __exit slcan_exit(void)
-{
- int i;
- struct net_device *dev;
- struct slcan *sl;
- unsigned long timeout = jiffies + HZ;
- int busy = 0;
-
- if (slcan_devs == NULL)
- return;
-
- /* First of all: check for active disciplines and hangup them.
- */
- do {
- if (busy)
- msleep_interruptible(100);
-
- busy = 0;
- for (i = 0; i < maxdev; i++) {
- dev = slcan_devs[i];
- if (!dev)
- continue;
- sl = netdev_priv(dev);
- spin_lock_bh(&sl->lock);
- if (sl->tty) {
- busy++;
- tty_hangup(sl->tty);
- }
- spin_unlock_bh(&sl->lock);
- }
- } while (busy && time_before(jiffies, timeout));
-
- /* FIXME: hangup is async so we should wait when doing this second
- phase */
-
- for (i = 0; i < maxdev; i++) {
- dev = slcan_devs[i];
- if (!dev)
- continue;
-
- sl = netdev_priv(dev);
- if (sl->tty) {
- netdev_err(dev, "tty discipline still running\n");
- }
-
- slc_close(dev);
- unregister_candev(dev);
- slc_dealloc(sl);
- }
-
- kfree(slcan_devs);
- slcan_devs = NULL;
-
- tty_unregister_ldisc(&slc_ldisc);
-}
-
-module_init(slcan_init);
-module_exit(slcan_exit);
--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_CAN_SLCAN) += slcan.o
+
+slcan-objs :=
+slcan-objs += slcan-core.o
--- /dev/null
+/*
+ * slcan.c - serial line CAN interface driver (using tty line discipline)
+ *
+ * This file is derived from linux/drivers/net/slip/slip.c
+ *
+ * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
+ * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
+ * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see http://www.gnu.org/licenses/gpl.html
+ *
+ * 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/moduleparam.h>
+
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <linux/tty.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/skb.h>
+
+MODULE_ALIAS_LDISC(N_SLCAN);
+MODULE_DESCRIPTION("serial line CAN interface");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
+
+#define SLCAN_MAGIC 0x53CA
+
+static int maxdev = 10; /* MAX number of SLCAN channels;
+ This can be overridden with
+ insmod slcan.ko maxdev=nnn */
+module_param(maxdev, int, 0);
+MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
+
+/* maximum rx buffer len: extended CAN frame with timestamp */
+#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
+
+#define SLC_CMD_LEN 1
+#define SLC_SFF_ID_LEN 3
+#define SLC_EFF_ID_LEN 8
+
+struct slcan {
+ struct can_priv can;
+ int magic;
+
+ /* Various fields. */
+ struct tty_struct *tty; /* ptr to TTY structure */
+ struct net_device *dev; /* easy for intr handling */
+ spinlock_t lock;
+ struct work_struct tx_work; /* Flushes transmit buffer */
+
+ /* These are pointers to the malloc()ed frame buffers. */
+ unsigned char rbuff[SLC_MTU]; /* receiver buffer */
+ int rcount; /* received chars counter */
+ unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
+ unsigned char *xhead; /* pointer to next XMIT byte */
+ int xleft; /* bytes left in XMIT queue */
+
+ unsigned long flags; /* Flag values/ mode etc */
+#define SLF_INUSE 0 /* Channel in use */
+#define SLF_ERROR 1 /* Parity, etc. error */
+#define SLF_XCMD 2 /* Command transmission */
+ wait_queue_head_t xcmd_wait; /* Wait queue for commands */
+ /* transmission */
+};
+
+static struct net_device **slcan_devs;
+
+static const u32 slcan_bitrate_const[] = {
+ 10000, 20000, 50000, 100000, 125000,
+ 250000, 500000, 800000, 1000000
+};
+
+ /************************************************************************
+ * SLCAN ENCAPSULATION FORMAT *
+ ************************************************************************/
+
+/*
+ * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
+ * frame format) a data length code (len) which can be from 0 to 8
+ * and up to <len> data bytes as payload.
+ * Additionally a CAN frame may become a remote transmission frame if the
+ * RTR-bit is set. This causes another ECU to send a CAN frame with the
+ * given can_id.
+ *
+ * The SLCAN ASCII representation of these different frame types is:
+ * <type> <id> <dlc> <data>*
+ *
+ * Extended frames (29 bit) are defined by capital characters in the type.
+ * RTR frames are defined as 'r' types - normal frames have 't' type:
+ * t => 11 bit data frame
+ * r => 11 bit RTR frame
+ * T => 29 bit data frame
+ * R => 29 bit RTR frame
+ *
+ * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
+ * The <dlc> is a one byte ASCII number ('0' - '8')
+ * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
+ *
+ * Examples:
+ *
+ * t1230 : can_id 0x123, len 0, no data
+ * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33
+ * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55
+ * r1230 : can_id 0x123, len 0, no data, remote transmission request
+ *
+ */
+
+ /************************************************************************
+ * STANDARD SLCAN DECAPSULATION *
+ ************************************************************************/
+
+/* Send one completely decapsulated can_frame to the network layer */
+static void slc_bump(struct slcan *sl)
+{
+ struct sk_buff *skb;
+ struct can_frame *cf;
+ int i, tmp;
+ u32 tmpid;
+ char *cmd = sl->rbuff;
+
+ skb = alloc_can_skb(sl->dev, &cf);
+ if (unlikely(!skb)) {
+ sl->dev->stats.rx_dropped++;
+ return;
+ }
+
+ switch (*cmd) {
+ case 'r':
+ cf->can_id = CAN_RTR_FLAG;
+ fallthrough;
+ case 't':
+ /* store dlc ASCII value and terminate SFF CAN ID string */
+ cf->len = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];
+ sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;
+ /* point to payload data behind the dlc */
+ cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;
+ break;
+ case 'R':
+ cf->can_id = CAN_RTR_FLAG;
+ fallthrough;
+ case 'T':
+ cf->can_id |= CAN_EFF_FLAG;
+ /* store dlc ASCII value and terminate EFF CAN ID string */
+ cf->len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];
+ sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;
+ /* point to payload data behind the dlc */
+ cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;
+ break;
+ default:
+ goto decode_failed;
+ }
+
+ if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))
+ goto decode_failed;
+
+ cf->can_id |= tmpid;
+
+ /* get len from sanitized ASCII value */
+ if (cf->len >= '0' && cf->len < '9')
+ cf->len -= '0';
+ else
+ goto decode_failed;
+
+ /* RTR frames may have a dlc > 0 but they never have any data bytes */
+ if (!(cf->can_id & CAN_RTR_FLAG)) {
+ for (i = 0; i < cf->len; i++) {
+ tmp = hex_to_bin(*cmd++);
+ if (tmp < 0)
+ goto decode_failed;
+
+ cf->data[i] = (tmp << 4);
+ tmp = hex_to_bin(*cmd++);
+ if (tmp < 0)
+ goto decode_failed;
+
+ cf->data[i] |= tmp;
+ }
+ }
+
+ sl->dev->stats.rx_packets++;
+ if (!(cf->can_id & CAN_RTR_FLAG))
+ sl->dev->stats.rx_bytes += cf->len;
+
+ netif_rx(skb);
+ return;
+
+decode_failed:
+ sl->dev->stats.rx_errors++;
+ dev_kfree_skb(skb);
+}
+
+/* parse tty input stream */
+static void slcan_unesc(struct slcan *sl, unsigned char s)
+{
+ if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
+ if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
+ (sl->rcount > 4)) {
+ slc_bump(sl);
+ }
+ sl->rcount = 0;
+ } else {
+ if (!test_bit(SLF_ERROR, &sl->flags)) {
+ if (sl->rcount < SLC_MTU) {
+ sl->rbuff[sl->rcount++] = s;
+ return;
+ } else {
+ sl->dev->stats.rx_over_errors++;
+ set_bit(SLF_ERROR, &sl->flags);
+ }
+ }
+ }
+}
+
+ /************************************************************************
+ * STANDARD SLCAN ENCAPSULATION *
+ ************************************************************************/
+
+/* Encapsulate one can_frame and stuff into a TTY queue. */
+static void slc_encaps(struct slcan *sl, struct can_frame *cf)
+{
+ int actual, i;
+ unsigned char *pos;
+ unsigned char *endpos;
+ canid_t id = cf->can_id;
+
+ pos = sl->xbuff;
+
+ if (cf->can_id & CAN_RTR_FLAG)
+ *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
+ else
+ *pos = 'T'; /* becomes 't' in standard frame format (SSF) */
+
+ /* determine number of chars for the CAN-identifier */
+ if (cf->can_id & CAN_EFF_FLAG) {
+ id &= CAN_EFF_MASK;
+ endpos = pos + SLC_EFF_ID_LEN;
+ } else {
+ *pos |= 0x20; /* convert R/T to lower case for SFF */
+ id &= CAN_SFF_MASK;
+ endpos = pos + SLC_SFF_ID_LEN;
+ }
+
+ /* build 3 (SFF) or 8 (EFF) digit CAN identifier */
+ pos++;
+ while (endpos >= pos) {
+ *endpos-- = hex_asc_upper[id & 0xf];
+ id >>= 4;
+ }
+
+ pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;
+
+ *pos++ = cf->len + '0';
+
+ /* RTR frames may have a dlc > 0 but they never have any data bytes */
+ if (!(cf->can_id & CAN_RTR_FLAG)) {
+ for (i = 0; i < cf->len; i++)
+ pos = hex_byte_pack_upper(pos, cf->data[i]);
+
+ sl->dev->stats.tx_bytes += cf->len;
+ }
+
+ *pos++ = '\r';
+
+ /* Order of next two lines is *very* important.
+ * When we are sending a little amount of data,
+ * the transfer may be completed inside the ops->write()
+ * routine, because it's running with interrupts enabled.
+ * In this case we *never* got WRITE_WAKEUP event,
+ * if we did not request it before write operation.
+ * 14 Oct 1994 Dmitry Gorodchanin.
+ */
+ set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+ actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
+ sl->xleft = (pos - sl->xbuff) - actual;
+ sl->xhead = sl->xbuff + actual;
+}
+
+/* Write out any remaining transmit buffer. Scheduled when tty is writable */
+static void slcan_transmit(struct work_struct *work)
+{
+ struct slcan *sl = container_of(work, struct slcan, tx_work);
+ int actual;
+
+ spin_lock_bh(&sl->lock);
+ /* First make sure we're connected. */
+ if (!sl->tty || sl->magic != SLCAN_MAGIC ||
+ (unlikely(!netif_running(sl->dev)) &&
+ likely(!test_bit(SLF_XCMD, &sl->flags)))) {
+ spin_unlock_bh(&sl->lock);
+ return;
+ }
+
+ if (sl->xleft <= 0) {
+ if (unlikely(test_bit(SLF_XCMD, &sl->flags))) {
+ clear_bit(SLF_XCMD, &sl->flags);
+ clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+ spin_unlock_bh(&sl->lock);
+ wake_up(&sl->xcmd_wait);
+ return;
+ }
+
+ /* Now serial buffer is almost free & we can start
+ * transmission of another packet */
+ sl->dev->stats.tx_packets++;
+ clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+ spin_unlock_bh(&sl->lock);
+ netif_wake_queue(sl->dev);
+ return;
+ }
+
+ actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
+ sl->xleft -= actual;
+ sl->xhead += actual;
+ spin_unlock_bh(&sl->lock);
+}
+
+/*
+ * Called by the driver when there's room for more data.
+ * Schedule the transmit.
+ */
+static void slcan_write_wakeup(struct tty_struct *tty)
+{
+ struct slcan *sl;
+
+ rcu_read_lock();
+ sl = rcu_dereference(tty->disc_data);
+ if (sl)
+ schedule_work(&sl->tx_work);
+ rcu_read_unlock();
+}
+
+/* Send a can_frame to a TTY queue. */
+static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct slcan *sl = netdev_priv(dev);
+
+ if (can_dropped_invalid_skb(dev, skb))
+ return NETDEV_TX_OK;
+
+ spin_lock(&sl->lock);
+ if (!netif_running(dev)) {
+ spin_unlock(&sl->lock);
+ netdev_warn(dev, "xmit: iface is down\n");
+ goto out;
+ }
+ if (sl->tty == NULL) {
+ spin_unlock(&sl->lock);
+ goto out;
+ }
+
+ netif_stop_queue(sl->dev);
+ slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
+ spin_unlock(&sl->lock);
+
+out:
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+}
+
+
+/******************************************
+ * Routines looking at netdevice side.
+ ******************************************/
+
+static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd)
+{
+ int ret, actual, n;
+
+ spin_lock(&sl->lock);
+ if (!sl->tty) {
+ spin_unlock(&sl->lock);
+ return -ENODEV;
+ }
+
+ n = snprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd);
+ set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+ actual = sl->tty->ops->write(sl->tty, sl->xbuff, n);
+ sl->xleft = n - actual;
+ sl->xhead = sl->xbuff + actual;
+ set_bit(SLF_XCMD, &sl->flags);
+ spin_unlock(&sl->lock);
+ ret = wait_event_interruptible_timeout(sl->xcmd_wait,
+ !test_bit(SLF_XCMD, &sl->flags),
+ HZ);
+ clear_bit(SLF_XCMD, &sl->flags);
+ if (ret == -ERESTARTSYS)
+ return ret;
+
+ if (ret == 0)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+/* Netdevice UP -> DOWN routine */
+static int slc_close(struct net_device *dev)
+{
+ struct slcan *sl = netdev_priv(dev);
+ int err;
+
+ spin_lock_bh(&sl->lock);
+ if (sl->tty) {
+ if (sl->can.bittiming.bitrate &&
+ sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
+ spin_unlock_bh(&sl->lock);
+ err = slcan_transmit_cmd(sl, "C\r");
+ spin_lock_bh(&sl->lock);
+ if (err)
+ netdev_warn(dev,
+ "failed to send close command 'C\\r'\n");
+ }
+
+ /* TTY discipline is running. */
+ clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+ }
+ netif_stop_queue(dev);
+ close_candev(dev);
+ sl->can.state = CAN_STATE_STOPPED;
+ if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN)
+ sl->can.bittiming.bitrate = CAN_BITRATE_UNSET;
+
+ sl->rcount = 0;
+ sl->xleft = 0;
+ spin_unlock_bh(&sl->lock);
+
+ return 0;
+}
+
+/* Netdevice DOWN -> UP routine */
+static int slc_open(struct net_device *dev)
+{
+ struct slcan *sl = netdev_priv(dev);
+ unsigned char cmd[SLC_MTU];
+ int err, s;
+
+ if (sl->tty == NULL)
+ return -ENODEV;
+
+ /* The baud rate is not set with the command
+ * `ip link set <iface> type can bitrate <baud>' and therefore
+ * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing
+ * open_candev() to fail. So let's set to a fake value.
+ */
+ if (sl->can.bittiming.bitrate == CAN_BITRATE_UNSET)
+ sl->can.bittiming.bitrate = CAN_BITRATE_UNKNOWN;
+
+ err = open_candev(dev);
+ if (err) {
+ netdev_err(dev, "failed to open can device\n");
+ return err;
+ }
+
+ sl->flags &= BIT(SLF_INUSE);
+
+ if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
+ for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) {
+ if (sl->can.bittiming.bitrate == slcan_bitrate_const[s])
+ break;
+ }
+
+ /* The CAN framework has already validate the bitrate value,
+ * so we can avoid to check if `s' has been properly set.
+ */
+
+ snprintf(cmd, sizeof(cmd), "C\rS%d\r", s);
+ err = slcan_transmit_cmd(sl, cmd);
+ if (err) {
+ netdev_err(dev,
+ "failed to send bitrate command 'C\\rS%d\\r'\n",
+ s);
+ goto cmd_transmit_failed;
+ }
+
+ err = slcan_transmit_cmd(sl, "O\r");
+ if (err) {
+ netdev_err(dev, "failed to send open command 'O\\r'\n");
+ goto cmd_transmit_failed;
+ }
+ }
+
+ sl->can.state = CAN_STATE_ERROR_ACTIVE;
+ netif_start_queue(dev);
+ return 0;
+
+cmd_transmit_failed:
+ close_candev(dev);
+ return err;
+}
+
+static void slc_dealloc(struct slcan *sl)
+{
+ int i = sl->dev->base_addr;
+
+ free_candev(sl->dev);
+ slcan_devs[i] = NULL;
+}
+
+static int slcan_change_mtu(struct net_device *dev, int new_mtu)
+{
+ return -EINVAL;
+}
+
+static const struct net_device_ops slc_netdev_ops = {
+ .ndo_open = slc_open,
+ .ndo_stop = slc_close,
+ .ndo_start_xmit = slc_xmit,
+ .ndo_change_mtu = slcan_change_mtu,
+};
+
+/******************************************
+ Routines looking at TTY side.
+ ******************************************/
+
+/*
+ * Handle the 'receiver data ready' interrupt.
+ * This function is called by the 'tty_io' module in the kernel when
+ * a block of SLCAN data has been received, which can now be decapsulated
+ * and sent on to some IP layer for further processing. This will not
+ * be re-entered while running but other ldisc functions may be called
+ * in parallel
+ */
+
+static void slcan_receive_buf(struct tty_struct *tty,
+ const unsigned char *cp, const char *fp,
+ int count)
+{
+ struct slcan *sl = (struct slcan *) tty->disc_data;
+
+ if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
+ return;
+
+ /* Read the characters out of the buffer */
+ while (count--) {
+ if (fp && *fp++) {
+ if (!test_and_set_bit(SLF_ERROR, &sl->flags))
+ sl->dev->stats.rx_errors++;
+ cp++;
+ continue;
+ }
+ slcan_unesc(sl, *cp++);
+ }
+}
+
+/************************************
+ * slcan_open helper routines.
+ ************************************/
+
+/* Collect hanged up channels */
+static void slc_sync(void)
+{
+ int i;
+ struct net_device *dev;
+ struct slcan *sl;
+
+ for (i = 0; i < maxdev; i++) {
+ dev = slcan_devs[i];
+ if (dev == NULL)
+ break;
+
+ sl = netdev_priv(dev);
+ if (sl->tty)
+ continue;
+ if (dev->flags & IFF_UP)
+ dev_close(dev);
+ }
+}
+
+/* Find a free SLCAN channel, and link in this `tty' line. */
+static struct slcan *slc_alloc(void)
+{
+ int i;
+ struct net_device *dev = NULL;
+ struct slcan *sl;
+
+ for (i = 0; i < maxdev; i++) {
+ dev = slcan_devs[i];
+ if (dev == NULL)
+ break;
+
+ }
+
+ /* Sorry, too many, all slots in use */
+ if (i >= maxdev)
+ return NULL;
+
+ dev = alloc_candev(sizeof(*sl), 1);
+ if (!dev)
+ return NULL;
+
+ snprintf(dev->name, sizeof(dev->name), "slcan%d", i);
+ dev->netdev_ops = &slc_netdev_ops;
+ dev->base_addr = i;
+ sl = netdev_priv(dev);
+
+ /* Initialize channel control data */
+ sl->magic = SLCAN_MAGIC;
+ sl->dev = dev;
+ sl->can.bitrate_const = slcan_bitrate_const;
+ sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const);
+ spin_lock_init(&sl->lock);
+ INIT_WORK(&sl->tx_work, slcan_transmit);
+ init_waitqueue_head(&sl->xcmd_wait);
+ slcan_devs[i] = dev;
+
+ return sl;
+}
+
+/*
+ * Open the high-level part of the SLCAN channel.
+ * This function is called by the TTY module when the
+ * SLCAN line discipline is called for. Because we are
+ * sure the tty line exists, we only have to link it to
+ * a free SLCAN channel...
+ *
+ * Called in process context serialized from other ldisc calls.
+ */
+
+static int slcan_open(struct tty_struct *tty)
+{
+ struct slcan *sl;
+ int err;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ if (tty->ops->write == NULL)
+ return -EOPNOTSUPP;
+
+ /* RTnetlink lock is misused here to serialize concurrent
+ opens of slcan channels. There are better ways, but it is
+ the simplest one.
+ */
+ rtnl_lock();
+
+ /* Collect hanged up channels. */
+ slc_sync();
+
+ sl = tty->disc_data;
+
+ err = -EEXIST;
+ /* First make sure we're not already connected. */
+ if (sl && sl->magic == SLCAN_MAGIC)
+ goto err_exit;
+
+ /* OK. Find a free SLCAN channel to use. */
+ err = -ENFILE;
+ sl = slc_alloc();
+ if (sl == NULL)
+ goto err_exit;
+
+ sl->tty = tty;
+ tty->disc_data = sl;
+
+ if (!test_bit(SLF_INUSE, &sl->flags)) {
+ /* Perform the low-level SLCAN initialization. */
+ sl->rcount = 0;
+ sl->xleft = 0;
+
+ set_bit(SLF_INUSE, &sl->flags);
+
+ rtnl_unlock();
+ err = register_candev(sl->dev);
+ if (err) {
+ pr_err("slcan: can't register candev\n");
+ goto err_free_chan;
+ }
+ } else {
+ rtnl_unlock();
+ }
+
+ tty->receive_room = 65536; /* We don't flow control */
+
+ /* TTY layer expects 0 on success */
+ return 0;
+
+err_free_chan:
+ rtnl_lock();
+ sl->tty = NULL;
+ tty->disc_data = NULL;
+ clear_bit(SLF_INUSE, &sl->flags);
+ slc_dealloc(sl);
+ rtnl_unlock();
+ return err;
+
+err_exit:
+ rtnl_unlock();
+
+ /* Count references from TTY module */
+ return err;
+}
+
+/*
+ * Close down a SLCAN channel.
+ * This means flushing out any pending queues, and then returning. This
+ * call is serialized against other ldisc functions.
+ *
+ * We also use this method for a hangup event.
+ */
+
+static void slcan_close(struct tty_struct *tty)
+{
+ struct slcan *sl = (struct slcan *) tty->disc_data;
+
+ /* First make sure we're connected. */
+ if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
+ return;
+
+ spin_lock_bh(&sl->lock);
+ rcu_assign_pointer(tty->disc_data, NULL);
+ sl->tty = NULL;
+ spin_unlock_bh(&sl->lock);
+
+ synchronize_rcu();
+ flush_work(&sl->tx_work);
+
+ slc_close(sl->dev);
+ unregister_candev(sl->dev);
+ rtnl_lock();
+ slc_dealloc(sl);
+ rtnl_unlock();
+}
+
+static void slcan_hangup(struct tty_struct *tty)
+{
+ slcan_close(tty);
+}
+
+/* Perform I/O control on an active SLCAN channel. */
+static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,
+ unsigned long arg)
+{
+ struct slcan *sl = (struct slcan *) tty->disc_data;
+ unsigned int tmp;
+
+ /* First make sure we're connected. */
+ if (!sl || sl->magic != SLCAN_MAGIC)
+ return -EINVAL;
+
+ switch (cmd) {
+ case SIOCGIFNAME:
+ tmp = strlen(sl->dev->name) + 1;
+ if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
+ return -EFAULT;
+ return 0;
+
+ case SIOCSIFHWADDR:
+ return -EINVAL;
+
+ default:
+ return tty_mode_ioctl(tty, cmd, arg);
+ }
+}
+
+static struct tty_ldisc_ops slc_ldisc = {
+ .owner = THIS_MODULE,
+ .num = N_SLCAN,
+ .name = "slcan",
+ .open = slcan_open,
+ .close = slcan_close,
+ .hangup = slcan_hangup,
+ .ioctl = slcan_ioctl,
+ .receive_buf = slcan_receive_buf,
+ .write_wakeup = slcan_write_wakeup,
+};
+
+static int __init slcan_init(void)
+{
+ int status;
+
+ if (maxdev < 4)
+ maxdev = 4; /* Sanity */
+
+ pr_info("slcan: serial line CAN interface driver\n");
+ pr_info("slcan: %d dynamic interface channels.\n", maxdev);
+
+ slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);
+ if (!slcan_devs)
+ return -ENOMEM;
+
+ /* Fill in our line protocol discipline, and register it */
+ status = tty_register_ldisc(&slc_ldisc);
+ if (status) {
+ printk(KERN_ERR "slcan: can't register line discipline\n");
+ kfree(slcan_devs);
+ }
+ return status;
+}
+
+static void __exit slcan_exit(void)
+{
+ int i;
+ struct net_device *dev;
+ struct slcan *sl;
+ unsigned long timeout = jiffies + HZ;
+ int busy = 0;
+
+ if (slcan_devs == NULL)
+ return;
+
+ /* First of all: check for active disciplines and hangup them.
+ */
+ do {
+ if (busy)
+ msleep_interruptible(100);
+
+ busy = 0;
+ for (i = 0; i < maxdev; i++) {
+ dev = slcan_devs[i];
+ if (!dev)
+ continue;
+ sl = netdev_priv(dev);
+ spin_lock_bh(&sl->lock);
+ if (sl->tty) {
+ busy++;
+ tty_hangup(sl->tty);
+ }
+ spin_unlock_bh(&sl->lock);
+ }
+ } while (busy && time_before(jiffies, timeout));
+
+ /* FIXME: hangup is async so we should wait when doing this second
+ phase */
+
+ for (i = 0; i < maxdev; i++) {
+ dev = slcan_devs[i];
+ if (!dev)
+ continue;
+
+ sl = netdev_priv(dev);
+ if (sl->tty) {
+ netdev_err(dev, "tty discipline still running\n");
+ }
+
+ slc_close(dev);
+ unregister_candev(dev);
+ slc_dealloc(sl);
+ }
+
+ kfree(slcan_devs);
+ slcan_devs = NULL;
+
+ tty_unregister_ldisc(&slc_ldisc);
+}
+
+module_init(slcan_init);
+module_exit(slcan_exit);
projects / kernel.git / commitdiff