/*
|
* 6pack.c This module implements the 6pack protocol for kernel-based
|
* devices like TTY. It interfaces between a raw TTY and the
|
* kernel's AX.25 protocol layers.
|
*
|
* Authors: Andreas Könsgen <ajk@comnets.uni-bremen.de>
|
* Ralf Baechle DL5RB <ralf@linux-mips.org>
|
*
|
* Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by
|
*
|
* Laurence Culhane, <loz@holmes.demon.co.uk>
|
* Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
|
*/
|
|
#include <linux/module.h>
|
#include <linux/uaccess.h>
|
#include <linux/bitops.h>
|
#include <linux/string.h>
|
#include <linux/mm.h>
|
#include <linux/interrupt.h>
|
#include <linux/in.h>
|
#include <linux/tty.h>
|
#include <linux/errno.h>
|
#include <linux/netdevice.h>
|
#include <linux/timer.h>
|
#include <linux/slab.h>
|
#include <net/ax25.h>
|
#include <linux/etherdevice.h>
|
#include <linux/skbuff.h>
|
#include <linux/rtnetlink.h>
|
#include <linux/spinlock.h>
|
#include <linux/if_arp.h>
|
#include <linux/init.h>
|
#include <linux/ip.h>
|
#include <linux/tcp.h>
|
#include <linux/semaphore.h>
|
#include <linux/compat.h>
|
#include <linux/refcount.h>
|
|
#define SIXPACK_VERSION "Revision: 0.3.0"
|
|
/* sixpack priority commands */
|
#define SIXP_SEOF 0x40 /* start and end of a 6pack frame */
|
#define SIXP_TX_URUN 0x48 /* transmit overrun */
|
#define SIXP_RX_ORUN 0x50 /* receive overrun */
|
#define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */
|
|
#define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */
|
|
/* masks to get certain bits out of the status bytes sent by the TNC */
|
|
#define SIXP_CMD_MASK 0xC0
|
#define SIXP_CHN_MASK 0x07
|
#define SIXP_PRIO_CMD_MASK 0x80
|
#define SIXP_STD_CMD_MASK 0x40
|
#define SIXP_PRIO_DATA_MASK 0x38
|
#define SIXP_TX_MASK 0x20
|
#define SIXP_RX_MASK 0x10
|
#define SIXP_RX_DCD_MASK 0x18
|
#define SIXP_LEDS_ON 0x78
|
#define SIXP_LEDS_OFF 0x60
|
#define SIXP_CON 0x08
|
#define SIXP_STA 0x10
|
|
#define SIXP_FOUND_TNC 0xe9
|
#define SIXP_CON_ON 0x68
|
#define SIXP_DCD_MASK 0x08
|
#define SIXP_DAMA_OFF 0
|
|
/* default level 2 parameters */
|
#define SIXP_TXDELAY 25 /* 250 ms */
|
#define SIXP_PERSIST 50 /* in 256ths */
|
#define SIXP_SLOTTIME 10 /* 100 ms */
|
#define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */
|
#define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */
|
|
/* 6pack configuration. */
|
#define SIXP_NRUNIT 31 /* MAX number of 6pack channels */
|
#define SIXP_MTU 256 /* Default MTU */
|
|
enum sixpack_flags {
|
SIXPF_ERROR, /* Parity, etc. error */
|
};
|
|
struct sixpack {
|
/* Various fields. */
|
struct tty_struct *tty; /* ptr to TTY structure */
|
struct net_device *dev; /* easy for intr handling */
|
|
/* These are pointers to the malloc()ed frame buffers. */
|
unsigned char *rbuff; /* receiver buffer */
|
int rcount; /* received chars counter */
|
unsigned char *xbuff; /* transmitter buffer */
|
unsigned char *xhead; /* next byte to XMIT */
|
int xleft; /* bytes left in XMIT queue */
|
|
unsigned char raw_buf[4];
|
unsigned char cooked_buf[400];
|
|
unsigned int rx_count;
|
unsigned int rx_count_cooked;
|
|
int mtu; /* Our mtu (to spot changes!) */
|
int buffsize; /* Max buffers sizes */
|
|
unsigned long flags; /* Flag values/ mode etc */
|
unsigned char mode; /* 6pack mode */
|
|
/* 6pack stuff */
|
unsigned char tx_delay;
|
unsigned char persistence;
|
unsigned char slottime;
|
unsigned char duplex;
|
unsigned char led_state;
|
unsigned char status;
|
unsigned char status1;
|
unsigned char status2;
|
unsigned char tx_enable;
|
unsigned char tnc_state;
|
|
struct timer_list tx_t;
|
struct timer_list resync_t;
|
refcount_t refcnt;
|
struct semaphore dead_sem;
|
spinlock_t lock;
|
};
|
|
#define AX25_6PACK_HEADER_LEN 0
|
|
static void sixpack_decode(struct sixpack *, const unsigned char[], int);
|
static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char);
|
|
/*
|
* Perform the persistence/slottime algorithm for CSMA access. If the
|
* persistence check was successful, write the data to the serial driver.
|
* Note that in case of DAMA operation, the data is not sent here.
|
*/
|
|
static void sp_xmit_on_air(struct timer_list *t)
|
{
|
struct sixpack *sp = from_timer(sp, t, tx_t);
|
int actual, when = sp->slottime;
|
static unsigned char random;
|
|
random = random * 17 + 41;
|
|
if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) {
|
sp->led_state = 0x70;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
sp->tx_enable = 1;
|
actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
|
sp->xleft -= actual;
|
sp->xhead += actual;
|
sp->led_state = 0x60;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
sp->status2 = 0;
|
} else
|
mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);
|
}
|
|
/* ----> 6pack timer interrupt handler and friends. <---- */
|
|
/* Encapsulate one AX.25 frame and stuff into a TTY queue. */
|
static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
|
{
|
unsigned char *msg, *p = icp;
|
int actual, count;
|
|
if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
|
msg = "oversized transmit packet!";
|
goto out_drop;
|
}
|
|
if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */
|
msg = "oversized transmit packet!";
|
goto out_drop;
|
}
|
|
if (p[0] > 5) {
|
msg = "invalid KISS command";
|
goto out_drop;
|
}
|
|
if ((p[0] != 0) && (len > 2)) {
|
msg = "KISS control packet too long";
|
goto out_drop;
|
}
|
|
if ((p[0] == 0) && (len < 15)) {
|
msg = "bad AX.25 packet to transmit";
|
goto out_drop;
|
}
|
|
count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay);
|
set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
|
|
switch (p[0]) {
|
case 1: sp->tx_delay = p[1];
|
return;
|
case 2: sp->persistence = p[1];
|
return;
|
case 3: sp->slottime = p[1];
|
return;
|
case 4: /* ignored */
|
return;
|
case 5: sp->duplex = p[1];
|
return;
|
}
|
|
if (p[0] != 0)
|
return;
|
|
/*
|
* In case of fullduplex or DAMA operation, we don't take care about the
|
* state of the DCD or of any timers, as the determination of the
|
* correct time to send is the job of the AX.25 layer. We send
|
* immediately after data has arrived.
|
*/
|
if (sp->duplex == 1) {
|
sp->led_state = 0x70;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
sp->tx_enable = 1;
|
actual = sp->tty->ops->write(sp->tty, sp->xbuff, count);
|
sp->xleft = count - actual;
|
sp->xhead = sp->xbuff + actual;
|
sp->led_state = 0x60;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
} else {
|
sp->xleft = count;
|
sp->xhead = sp->xbuff;
|
sp->status2 = count;
|
sp_xmit_on_air(&sp->tx_t);
|
}
|
|
return;
|
|
out_drop:
|
sp->dev->stats.tx_dropped++;
|
netif_start_queue(sp->dev);
|
if (net_ratelimit())
|
printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg);
|
}
|
|
/* Encapsulate an IP datagram and kick it into a TTY queue. */
|
|
static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev)
|
{
|
struct sixpack *sp = netdev_priv(dev);
|
|
if (skb->protocol == htons(ETH_P_IP))
|
return ax25_ip_xmit(skb);
|
|
spin_lock_bh(&sp->lock);
|
/* We were not busy, so we are now... :-) */
|
netif_stop_queue(dev);
|
dev->stats.tx_bytes += skb->len;
|
sp_encaps(sp, skb->data, skb->len);
|
spin_unlock_bh(&sp->lock);
|
|
dev_kfree_skb(skb);
|
|
return NETDEV_TX_OK;
|
}
|
|
static int sp_open_dev(struct net_device *dev)
|
{
|
struct sixpack *sp = netdev_priv(dev);
|
|
if (sp->tty == NULL)
|
return -ENODEV;
|
return 0;
|
}
|
|
/* Close the low-level part of the 6pack channel. */
|
static int sp_close(struct net_device *dev)
|
{
|
struct sixpack *sp = netdev_priv(dev);
|
|
spin_lock_bh(&sp->lock);
|
if (sp->tty) {
|
/* TTY discipline is running. */
|
clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags);
|
}
|
netif_stop_queue(dev);
|
spin_unlock_bh(&sp->lock);
|
|
return 0;
|
}
|
|
static int sp_set_mac_address(struct net_device *dev, void *addr)
|
{
|
struct sockaddr_ax25 *sa = addr;
|
|
netif_tx_lock_bh(dev);
|
netif_addr_lock(dev);
|
memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN);
|
netif_addr_unlock(dev);
|
netif_tx_unlock_bh(dev);
|
|
return 0;
|
}
|
|
static const struct net_device_ops sp_netdev_ops = {
|
.ndo_open = sp_open_dev,
|
.ndo_stop = sp_close,
|
.ndo_start_xmit = sp_xmit,
|
.ndo_set_mac_address = sp_set_mac_address,
|
};
|
|
static void sp_setup(struct net_device *dev)
|
{
|
/* Finish setting up the DEVICE info. */
|
dev->netdev_ops = &sp_netdev_ops;
|
dev->needs_free_netdev = true;
|
dev->mtu = SIXP_MTU;
|
dev->hard_header_len = AX25_MAX_HEADER_LEN;
|
dev->header_ops = &ax25_header_ops;
|
|
dev->addr_len = AX25_ADDR_LEN;
|
dev->type = ARPHRD_AX25;
|
dev->tx_queue_len = 10;
|
|
/* Only activated in AX.25 mode */
|
memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
|
memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
|
|
dev->flags = 0;
|
}
|
|
/* Send one completely decapsulated IP datagram to the IP layer. */
|
|
/*
|
* This is the routine that sends the received data to the kernel AX.25.
|
* 'cmd' is the KISS command. For AX.25 data, it is zero.
|
*/
|
|
static void sp_bump(struct sixpack *sp, char cmd)
|
{
|
struct sk_buff *skb;
|
int count;
|
unsigned char *ptr;
|
|
count = sp->rcount + 1;
|
|
sp->dev->stats.rx_bytes += count;
|
|
if ((skb = dev_alloc_skb(count)) == NULL)
|
goto out_mem;
|
|
ptr = skb_put(skb, count);
|
*ptr++ = cmd; /* KISS command */
|
|
memcpy(ptr, sp->cooked_buf + 1, count);
|
skb->protocol = ax25_type_trans(skb, sp->dev);
|
netif_rx(skb);
|
sp->dev->stats.rx_packets++;
|
|
return;
|
|
out_mem:
|
sp->dev->stats.rx_dropped++;
|
}
|
|
|
/* ----------------------------------------------------------------------- */
|
|
/*
|
* We have a potential race on dereferencing tty->disc_data, because the tty
|
* layer provides no locking at all - thus one cpu could be running
|
* sixpack_receive_buf while another calls sixpack_close, which zeroes
|
* tty->disc_data and frees the memory that sixpack_receive_buf is using. The
|
* best way to fix this is to use a rwlock in the tty struct, but for now we
|
* use a single global rwlock for all ttys in ppp line discipline.
|
*/
|
static DEFINE_RWLOCK(disc_data_lock);
|
|
static struct sixpack *sp_get(struct tty_struct *tty)
|
{
|
struct sixpack *sp;
|
|
read_lock(&disc_data_lock);
|
sp = tty->disc_data;
|
if (sp)
|
refcount_inc(&sp->refcnt);
|
read_unlock(&disc_data_lock);
|
|
return sp;
|
}
|
|
static void sp_put(struct sixpack *sp)
|
{
|
if (refcount_dec_and_test(&sp->refcnt))
|
up(&sp->dead_sem);
|
}
|
|
/*
|
* Called by the TTY driver when there's room for more data. If we have
|
* more packets to send, we send them here.
|
*/
|
static void sixpack_write_wakeup(struct tty_struct *tty)
|
{
|
struct sixpack *sp = sp_get(tty);
|
int actual;
|
|
if (!sp)
|
return;
|
if (sp->xleft <= 0) {
|
/* Now serial buffer is almost free & we can start
|
* transmission of another packet */
|
sp->dev->stats.tx_packets++;
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
sp->tx_enable = 0;
|
netif_wake_queue(sp->dev);
|
goto out;
|
}
|
|
if (sp->tx_enable) {
|
actual = tty->ops->write(tty, sp->xhead, sp->xleft);
|
sp->xleft -= actual;
|
sp->xhead += actual;
|
}
|
|
out:
|
sp_put(sp);
|
}
|
|
/* ----------------------------------------------------------------------- */
|
|
/*
|
* Handle the 'receiver data ready' interrupt.
|
* This function is called by the tty module in the kernel when
|
* a block of 6pack data has been received, which can now be decapsulated
|
* and sent on to some IP layer for further processing.
|
*/
|
static void sixpack_receive_buf(struct tty_struct *tty,
|
const unsigned char *cp, char *fp, int count)
|
{
|
struct sixpack *sp;
|
int count1;
|
|
if (!count)
|
return;
|
|
sp = sp_get(tty);
|
if (!sp)
|
return;
|
|
/* Read the characters out of the buffer */
|
count1 = count;
|
while (count) {
|
count--;
|
if (fp && *fp++) {
|
if (!test_and_set_bit(SIXPF_ERROR, &sp->flags))
|
sp->dev->stats.rx_errors++;
|
continue;
|
}
|
}
|
sixpack_decode(sp, cp, count1);
|
|
sp_put(sp);
|
tty_unthrottle(tty);
|
}
|
|
/*
|
* Try to resync the TNC. Called by the resync timer defined in
|
* decode_prio_command
|
*/
|
|
#define TNC_UNINITIALIZED 0
|
#define TNC_UNSYNC_STARTUP 1
|
#define TNC_UNSYNCED 2
|
#define TNC_IN_SYNC 3
|
|
static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
|
{
|
char *msg;
|
|
switch (new_tnc_state) {
|
default: /* gcc oh piece-o-crap ... */
|
case TNC_UNSYNC_STARTUP:
|
msg = "Synchronizing with TNC";
|
break;
|
case TNC_UNSYNCED:
|
msg = "Lost synchronization with TNC\n";
|
break;
|
case TNC_IN_SYNC:
|
msg = "Found TNC";
|
break;
|
}
|
|
sp->tnc_state = new_tnc_state;
|
printk(KERN_INFO "%s: %s\n", sp->dev->name, msg);
|
}
|
|
static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state)
|
{
|
int old_tnc_state = sp->tnc_state;
|
|
if (old_tnc_state != new_tnc_state)
|
__tnc_set_sync_state(sp, new_tnc_state);
|
}
|
|
static void resync_tnc(struct timer_list *t)
|
{
|
struct sixpack *sp = from_timer(sp, t, resync_t);
|
static char resync_cmd = 0xe8;
|
|
/* clear any data that might have been received */
|
|
sp->rx_count = 0;
|
sp->rx_count_cooked = 0;
|
|
/* reset state machine */
|
|
sp->status = 1;
|
sp->status1 = 1;
|
sp->status2 = 0;
|
|
/* resync the TNC */
|
|
sp->led_state = 0x60;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
sp->tty->ops->write(sp->tty, &resync_cmd, 1);
|
|
|
/* Start resync timer again -- the TNC might be still absent */
|
mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
|
}
|
|
static inline int tnc_init(struct sixpack *sp)
|
{
|
unsigned char inbyte = 0xe8;
|
|
tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP);
|
|
sp->tty->ops->write(sp->tty, &inbyte, 1);
|
|
mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
|
|
return 0;
|
}
|
|
/*
|
* Open the high-level part of the 6pack channel.
|
* This function is called by the TTY module when the
|
* 6pack line discipline is called for. Because we are
|
* sure the tty line exists, we only have to link it to
|
* a free 6pcack channel...
|
*/
|
static int sixpack_open(struct tty_struct *tty)
|
{
|
char *rbuff = NULL, *xbuff = NULL;
|
struct net_device *dev;
|
struct sixpack *sp;
|
unsigned long len;
|
int err = 0;
|
|
if (!capable(CAP_NET_ADMIN))
|
return -EPERM;
|
if (tty->ops->write == NULL)
|
return -EOPNOTSUPP;
|
|
dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN,
|
sp_setup);
|
if (!dev) {
|
err = -ENOMEM;
|
goto out;
|
}
|
|
sp = netdev_priv(dev);
|
sp->dev = dev;
|
|
spin_lock_init(&sp->lock);
|
refcount_set(&sp->refcnt, 1);
|
sema_init(&sp->dead_sem, 0);
|
|
/* !!! length of the buffers. MTU is IP MTU, not PACLEN! */
|
|
len = dev->mtu * 2;
|
|
rbuff = kmalloc(len + 4, GFP_KERNEL);
|
xbuff = kmalloc(len + 4, GFP_KERNEL);
|
|
if (rbuff == NULL || xbuff == NULL) {
|
err = -ENOBUFS;
|
goto out_free;
|
}
|
|
spin_lock_bh(&sp->lock);
|
|
sp->tty = tty;
|
|
sp->rbuff = rbuff;
|
sp->xbuff = xbuff;
|
|
sp->mtu = AX25_MTU + 73;
|
sp->buffsize = len;
|
sp->rcount = 0;
|
sp->rx_count = 0;
|
sp->rx_count_cooked = 0;
|
sp->xleft = 0;
|
|
sp->flags = 0; /* Clear ESCAPE & ERROR flags */
|
|
sp->duplex = 0;
|
sp->tx_delay = SIXP_TXDELAY;
|
sp->persistence = SIXP_PERSIST;
|
sp->slottime = SIXP_SLOTTIME;
|
sp->led_state = 0x60;
|
sp->status = 1;
|
sp->status1 = 1;
|
sp->status2 = 0;
|
sp->tx_enable = 0;
|
|
netif_start_queue(dev);
|
|
timer_setup(&sp->tx_t, sp_xmit_on_air, 0);
|
|
timer_setup(&sp->resync_t, resync_tnc, 0);
|
|
spin_unlock_bh(&sp->lock);
|
|
/* Done. We have linked the TTY line to a channel. */
|
tty->disc_data = sp;
|
tty->receive_room = 65536;
|
|
/* Now we're ready to register. */
|
err = register_netdev(dev);
|
if (err)
|
goto out_free;
|
|
tnc_init(sp);
|
|
return 0;
|
|
out_free:
|
kfree(xbuff);
|
kfree(rbuff);
|
|
free_netdev(dev);
|
|
out:
|
return err;
|
}
|
|
|
/*
|
* Close down a 6pack channel.
|
* This means flushing out any pending queues, and then restoring the
|
* TTY line discipline to what it was before it got hooked to 6pack
|
* (which usually is TTY again).
|
*/
|
static void sixpack_close(struct tty_struct *tty)
|
{
|
struct sixpack *sp;
|
|
write_lock_irq(&disc_data_lock);
|
sp = tty->disc_data;
|
tty->disc_data = NULL;
|
write_unlock_irq(&disc_data_lock);
|
if (!sp)
|
return;
|
|
/*
|
* We have now ensured that nobody can start using ap from now on, but
|
* we have to wait for all existing users to finish.
|
*/
|
if (!refcount_dec_and_test(&sp->refcnt))
|
down(&sp->dead_sem);
|
|
/* We must stop the queue to avoid potentially scribbling
|
* on the free buffers. The sp->dead_sem is not sufficient
|
* to protect us from sp->xbuff access.
|
*/
|
netif_stop_queue(sp->dev);
|
|
del_timer_sync(&sp->tx_t);
|
del_timer_sync(&sp->resync_t);
|
|
/* Free all 6pack frame buffers. */
|
kfree(sp->rbuff);
|
kfree(sp->xbuff);
|
|
unregister_netdev(sp->dev);
|
}
|
|
/* Perform I/O control on an active 6pack channel. */
|
static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
|
unsigned int cmd, unsigned long arg)
|
{
|
struct sixpack *sp = sp_get(tty);
|
struct net_device *dev;
|
unsigned int tmp, err;
|
|
if (!sp)
|
return -ENXIO;
|
dev = sp->dev;
|
|
switch(cmd) {
|
case SIOCGIFNAME:
|
err = copy_to_user((void __user *) arg, dev->name,
|
strlen(dev->name) + 1) ? -EFAULT : 0;
|
break;
|
|
case SIOCGIFENCAP:
|
err = put_user(0, (int __user *) arg);
|
break;
|
|
case SIOCSIFENCAP:
|
if (get_user(tmp, (int __user *) arg)) {
|
err = -EFAULT;
|
break;
|
}
|
|
sp->mode = tmp;
|
dev->addr_len = AX25_ADDR_LEN;
|
dev->hard_header_len = AX25_KISS_HEADER_LEN +
|
AX25_MAX_HEADER_LEN + 3;
|
dev->type = ARPHRD_AX25;
|
|
err = 0;
|
break;
|
|
case SIOCSIFHWADDR: {
|
char addr[AX25_ADDR_LEN];
|
|
if (copy_from_user(&addr,
|
(void __user *) arg, AX25_ADDR_LEN)) {
|
err = -EFAULT;
|
break;
|
}
|
|
netif_tx_lock_bh(dev);
|
memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN);
|
netif_tx_unlock_bh(dev);
|
|
err = 0;
|
break;
|
}
|
|
default:
|
err = tty_mode_ioctl(tty, file, cmd, arg);
|
}
|
|
sp_put(sp);
|
|
return err;
|
}
|
|
#ifdef CONFIG_COMPAT
|
static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file,
|
unsigned int cmd, unsigned long arg)
|
{
|
switch (cmd) {
|
case SIOCGIFNAME:
|
case SIOCGIFENCAP:
|
case SIOCSIFENCAP:
|
case SIOCSIFHWADDR:
|
return sixpack_ioctl(tty, file, cmd,
|
(unsigned long)compat_ptr(arg));
|
}
|
|
return -ENOIOCTLCMD;
|
}
|
#endif
|
|
static struct tty_ldisc_ops sp_ldisc = {
|
.owner = THIS_MODULE,
|
.magic = TTY_LDISC_MAGIC,
|
.name = "6pack",
|
.open = sixpack_open,
|
.close = sixpack_close,
|
.ioctl = sixpack_ioctl,
|
#ifdef CONFIG_COMPAT
|
.compat_ioctl = sixpack_compat_ioctl,
|
#endif
|
.receive_buf = sixpack_receive_buf,
|
.write_wakeup = sixpack_write_wakeup,
|
};
|
|
/* Initialize 6pack control device -- register 6pack line discipline */
|
|
static const char msg_banner[] __initconst = KERN_INFO \
|
"AX.25: 6pack driver, " SIXPACK_VERSION "\n";
|
static const char msg_regfail[] __initconst = KERN_ERR \
|
"6pack: can't register line discipline (err = %d)\n";
|
|
static int __init sixpack_init_driver(void)
|
{
|
int status;
|
|
printk(msg_banner);
|
|
/* Register the provided line protocol discipline */
|
if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0)
|
printk(msg_regfail, status);
|
|
return status;
|
}
|
|
static const char msg_unregfail[] = KERN_ERR \
|
"6pack: can't unregister line discipline (err = %d)\n";
|
|
static void __exit sixpack_exit_driver(void)
|
{
|
int ret;
|
|
if ((ret = tty_unregister_ldisc(N_6PACK)))
|
printk(msg_unregfail, ret);
|
}
|
|
/* encode an AX.25 packet into 6pack */
|
|
static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw,
|
int length, unsigned char tx_delay)
|
{
|
int count = 0;
|
unsigned char checksum = 0, buf[400];
|
int raw_count = 0;
|
|
tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK;
|
tx_buf_raw[raw_count++] = SIXP_SEOF;
|
|
buf[0] = tx_delay;
|
for (count = 1; count < length; count++)
|
buf[count] = tx_buf[count];
|
|
for (count = 0; count < length; count++)
|
checksum += buf[count];
|
buf[length] = (unsigned char) 0xff - checksum;
|
|
for (count = 0; count <= length; count++) {
|
if ((count % 3) == 0) {
|
tx_buf_raw[raw_count++] = (buf[count] & 0x3f);
|
tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30);
|
} else if ((count % 3) == 1) {
|
tx_buf_raw[raw_count++] |= (buf[count] & 0x0f);
|
tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c);
|
} else {
|
tx_buf_raw[raw_count++] |= (buf[count] & 0x03);
|
tx_buf_raw[raw_count++] = (buf[count] >> 2);
|
}
|
}
|
if ((length % 3) != 2)
|
raw_count++;
|
tx_buf_raw[raw_count++] = SIXP_SEOF;
|
return raw_count;
|
}
|
|
/* decode 4 sixpack-encoded bytes into 3 data bytes */
|
|
static void decode_data(struct sixpack *sp, unsigned char inbyte)
|
{
|
unsigned char *buf;
|
|
if (sp->rx_count != 3) {
|
sp->raw_buf[sp->rx_count++] = inbyte;
|
|
return;
|
}
|
|
if (sp->rx_count_cooked + 2 >= sizeof(sp->cooked_buf)) {
|
pr_err("6pack: cooked buffer overrun, data loss\n");
|
sp->rx_count = 0;
|
return;
|
}
|
|
buf = sp->raw_buf;
|
sp->cooked_buf[sp->rx_count_cooked++] =
|
buf[0] | ((buf[1] << 2) & 0xc0);
|
sp->cooked_buf[sp->rx_count_cooked++] =
|
(buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0);
|
sp->cooked_buf[sp->rx_count_cooked++] =
|
(buf[2] & 0x03) | (inbyte << 2);
|
sp->rx_count = 0;
|
}
|
|
/* identify and execute a 6pack priority command byte */
|
|
static void decode_prio_command(struct sixpack *sp, unsigned char cmd)
|
{
|
int actual;
|
|
if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */
|
|
/* RX and DCD flags can only be set in the same prio command,
|
if the DCD flag has been set without the RX flag in the previous
|
prio command. If DCD has not been set before, something in the
|
transmission has gone wrong. In this case, RX and DCD are
|
cleared in order to prevent the decode_data routine from
|
reading further data that might be corrupt. */
|
|
if (((sp->status & SIXP_DCD_MASK) == 0) &&
|
((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) {
|
if (sp->status != 1)
|
printk(KERN_DEBUG "6pack: protocol violation\n");
|
else
|
sp->status = 0;
|
cmd &= ~SIXP_RX_DCD_MASK;
|
}
|
sp->status = cmd & SIXP_PRIO_DATA_MASK;
|
} else { /* output watchdog char if idle */
|
if ((sp->status2 != 0) && (sp->duplex == 1)) {
|
sp->led_state = 0x70;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
sp->tx_enable = 1;
|
actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2);
|
sp->xleft -= actual;
|
sp->xhead += actual;
|
sp->led_state = 0x60;
|
sp->status2 = 0;
|
|
}
|
}
|
|
/* needed to trigger the TNC watchdog */
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
|
/* if the state byte has been received, the TNC is present,
|
so the resync timer can be reset. */
|
|
if (sp->tnc_state == TNC_IN_SYNC)
|
mod_timer(&sp->resync_t, jiffies + SIXP_INIT_RESYNC_TIMEOUT);
|
|
sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
|
}
|
|
/* identify and execute a standard 6pack command byte */
|
|
static void decode_std_command(struct sixpack *sp, unsigned char cmd)
|
{
|
unsigned char checksum = 0, rest = 0;
|
short i;
|
|
switch (cmd & SIXP_CMD_MASK) { /* normal command */
|
case SIXP_SEOF:
|
if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) {
|
if ((sp->status & SIXP_RX_DCD_MASK) ==
|
SIXP_RX_DCD_MASK) {
|
sp->led_state = 0x68;
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
}
|
} else {
|
sp->led_state = 0x60;
|
/* fill trailing bytes with zeroes */
|
sp->tty->ops->write(sp->tty, &sp->led_state, 1);
|
rest = sp->rx_count;
|
if (rest != 0)
|
for (i = rest; i <= 3; i++)
|
decode_data(sp, 0);
|
if (rest == 2)
|
sp->rx_count_cooked -= 2;
|
else if (rest == 3)
|
sp->rx_count_cooked -= 1;
|
for (i = 0; i < sp->rx_count_cooked; i++)
|
checksum += sp->cooked_buf[i];
|
if (checksum != SIXP_CHKSUM) {
|
printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum);
|
} else {
|
sp->rcount = sp->rx_count_cooked-2;
|
sp_bump(sp, 0);
|
}
|
sp->rx_count_cooked = 0;
|
}
|
break;
|
case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n");
|
break;
|
case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n");
|
break;
|
case SIXP_RX_BUF_OVL:
|
printk(KERN_DEBUG "6pack: RX buffer overflow\n");
|
}
|
}
|
|
/* decode a 6pack packet */
|
|
static void
|
sixpack_decode(struct sixpack *sp, const unsigned char *pre_rbuff, int count)
|
{
|
unsigned char inbyte;
|
int count1;
|
|
for (count1 = 0; count1 < count; count1++) {
|
inbyte = pre_rbuff[count1];
|
if (inbyte == SIXP_FOUND_TNC) {
|
tnc_set_sync_state(sp, TNC_IN_SYNC);
|
del_timer(&sp->resync_t);
|
}
|
if ((inbyte & SIXP_PRIO_CMD_MASK) != 0)
|
decode_prio_command(sp, inbyte);
|
else if ((inbyte & SIXP_STD_CMD_MASK) != 0)
|
decode_std_command(sp, inbyte);
|
else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)
|
decode_data(sp, inbyte);
|
}
|
}
|
|
MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>");
|
MODULE_DESCRIPTION("6pack driver for AX.25");
|
MODULE_LICENSE("GPL");
|
MODULE_ALIAS_LDISC(N_6PACK);
|
|
module_init(sixpack_init_driver);
|
module_exit(sixpack_exit_driver);
|
