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/*
* 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, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it
* at 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/can.h>
static __initconst const char banner[] =
KERN_INFO "slcan: serial line CAN interface driver\n";
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)
struct slcan {
int magic;
/* Various fields. */
struct tty_struct *tty; /* ptr to TTY structure */
struct net_device *dev; /* easy for intr handling */
spinlock_t lock;
/* 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 */
};
static struct net_device **slcan_devs;
/************************************************************************
* 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 (can_dlc) which can be from 0 to 8
* and up to <can_dlc> 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, can_dlc 0, no data
* t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
* T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
* r1230 : can_id 0x123, can_dlc 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, dlc_pos, tmp;
unsigned long ultmp;
char cmd = sl->rbuff[0];
if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
return;
if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
dlc_pos = 4; /* dlc position tiiid */
else
dlc_pos = 9; /* dlc position Tiiiiiiiid */
if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
return;
cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
return;
cf.can_id = ultmp;
if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
cf.can_id |= CAN_EFF_FLAG;
if ((cmd | 0x20) == 'r') /* RTR frame */
cf.can_id |= CAN_RTR_FLAG;
*(u64 *) (&cf.data) = 0; /* clear payload */
for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
if (tmp < 0)
return;
cf.data[i] = (tmp << 4);
tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
if (tmp < 0)
return;
cf.data[i] |= tmp;
}
skb = dev_alloc_skb(sizeof(struct can_frame));
if (!skb)
return;
skb->dev = sl->dev;
skb->protocol = htons(ETH_P_CAN);
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
memcpy(skb_put(skb, sizeof(struct can_frame)),
&cf, sizeof(struct can_frame));
netif_rx_ni(skb);
sl->dev->stats.rx_packets++;
sl->dev->stats.rx_bytes += cf.can_dlc;
}
/* 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)
{
<
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