| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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/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 (HZ/4) /* in 1 s */ |
| #define SIXP_PERSIST 50 /* in 256ths */ |
| #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ |
| #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 completion dead; |
| 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 + 1)) == NULL) |
| goto out_mem; |
| |
| ptr = skb_put(skb, count + 1); |
| *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)) |
| complete(&sp->dead); |
| } |
| |
| /* |
| * 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); |
| init_completion(&sp->dead); |
| |
| /* !!! 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)) |
| wait_for_completion(&sp->dead); |
| |
| /* We must stop the queue to avoid potentially scribbling |
| * on the free buffers. The sp->dead completion 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; |
| } |
| |
| 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, |
| .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); |