/* * This program is free software; you can distribute it and/or modify it * under the terms of the GNU General Public License (Version 2) as * published by the Free Software Foundation. * * This program is distributed in the hope 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, USA. * * Copyright (C) Hans Alblas PE1AYX <hans@esrac.ele.tue.nl> * Copyright (C) 2004, 05 Ralf Baechle DL5RB <ralf@linux-mips.org> * Copyright (C) 2004, 05 Thomas Osterried DL9SAU <thomas@x-berg.in-berlin.de> */ #include <linux/module.h> #include <asm/system.h> #include <linux/bitops.h> #include <asm/uaccess.h> #include <linux/crc16.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/in.h> #include <linux/inet.h> #include <linux/tty.h> #include <linux/errno.h> #include <linux/netdevice.h> #include <linux/major.h> #include <linux/init.h> #include <linux/rtnetlink.h> #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <linux/if_arp.h> #include <linux/jiffies.h> #include <net/ax25.h> #define AX_MTU 236 /* SLIP/KISS protocol characters. */ #define END 0300 /* indicates end of frame */ #define ESC 0333 /* indicates byte stuffing */ #define ESC_END 0334 /* ESC ESC_END means END 'data' */ #define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */ struct mkiss { 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. */ spinlock_t buflock;/* lock for rbuf and xbuf */ unsigned char *rbuff; /* receiver buffer */ int rcount; /* received chars counter */ unsigned char *xbuff; /* transmitter buffer */ unsigned char *xhead; /* pointer to next byte to XMIT */ int xleft; /* bytes left in XMIT queue */ struct net_device_stats stats; /* Detailed SLIP statistics. */ int mtu; /* Our mtu (to spot changes!) */ int buffsize; /* Max buffers sizes */ unsigned long flags; /* Flag values/ mode etc */ /* long req'd: used by set_bit --RR */ #define AXF_INUSE 0 /* Channel in use */ #define AXF_ESCAPE 1 /* ESC received */ #define AXF_ERROR 2 /* Parity, etc. error */ #define AXF_KEEPTEST 3 /* Keepalive test flag */ #define AXF_OUTWAIT 4 /* is outpacket was flag */ int mode; int crcmode; /* MW: for FlexNet, SMACK etc. */ int crcauto; /* CRC auto mode */ #define CRC_MODE_NONE 0 #define CRC_MODE_FLEX 1 #define CRC_MODE_SMACK 2 #define CRC_MODE_FLEX_TEST 3 #define CRC_MODE_SMACK_TEST 4 atomic_t refcnt; struct semaphore dead_sem; }; /*---------------------------------------------------------------------------*/ static const unsigned short crc_flex_table[] = { 0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38, 0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770, 0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9, 0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1, 0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a, 0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672, 0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb, 0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3, 0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c, 0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574, 0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd, 0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5, 0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e, 0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476, 0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf, 0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7, 0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30, 0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378, 0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1, 0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9, 0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32, 0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a, 0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3, 0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb, 0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34, 0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c, 0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5, 0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd, 0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36, 0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e, 0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7, 0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff }; static unsigned short calc_crc_flex(unsigned char *cp, int size) { unsigned short crc = 0xffff; while (size--) crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; return crc; } static int check_crc_flex(unsigned char *cp, int size) { unsigned short crc = 0xffff; if (size < 3) return -1; while (size--) crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; if ((crc & 0xffff) != 0x7070) return -1; return 0; } static int check_crc_16(unsigned char *cp, int size) { unsigned short crc = 0x0000; if (size < 3) return -1; crc = crc16(0, cp, size); if (crc != 0x0000) return -1; return 0; } /* * Standard encapsulation */ static int kiss_esc(unsigned char *s, unsigned char *d, int len) { unsigned char *ptr = d; unsigned char c; /* * Send an initial END character to flush out any data that may have * accumulated in the receiver due to line noise. */ *ptr++ = END; while (len-- > 0) { switch (c = *s++) { case END: *ptr++ = ESC; *ptr++ = ESC_END; break; case ESC: *ptr++ = ESC; *ptr++ = ESC_ESC; break; default: *ptr++ = c; break; } } *ptr++ = END; return ptr - d; } /* * MW: * OK its ugly, but tell me a better solution without copying the * packet to a temporary buffer :-) */ static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc, int len) { unsigned char *ptr = d; unsigned char c=0; *ptr++ = END; while (len > 0) { if (len > 2) c = *s++; else if (len > 1) c = crc >> 8; else if (len > 0) c = crc & 0xff; len--; switch (c) { case END: *ptr++ = ESC; *ptr++ = ESC_END; break; case ESC: *ptr++ = ESC; *ptr++ = ESC_ESC; break; default: *ptr++ = c; break; } } *ptr++ = END; return ptr - d; } /* Send one completely decapsulated AX.25 packet to the AX.25 layer. */ static void ax_bump(struct mkiss *ax) { struct sk_buff *skb; int count; spin_lock_bh(&ax->buflock); if (ax->rbuff[0] > 0x0f) { if (ax->rbuff[0] & 0x80) { if (check_crc_16(ax->rbuff, ax->rcount) < 0) { ax->stats.rx_errors++; spin_unlock_bh(&ax->buflock); return; } if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) { printk(KERN_INFO "mkiss: %s: Switchting to crc-smack\n", ax->dev->name); ax->crcmode = CRC_MODE_SMACK; } ax->rcount -= 2; *ax->rbuff &= ~0x80; } else if (ax->rbuff[0] & 0x20) { if (check_crc_flex(ax->rbuff, ax->rcount) < 0) { ax->stats.rx_errors++; spin_unlock_bh(&ax->buflock); return; } if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) { printk(KERN_INFO "mkiss: %s: Switchting to crc-flexnet\n", ax->dev->name); ax->crcmode = CRC_MODE_FLEX; } ax->rcount -= 2; /* * dl9sau bugfix: the trailling two bytes flexnet crc * will not be passed to the kernel. thus we have to * correct the kissparm signature, because it indicates * a crc but there's none */ *ax->rbuff &= ~0x20; } } spin_unlock_bh(&ax->buflock); count = ax->rcount; if ((skb = dev_alloc_skb(count)) == NULL) { printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", ax->dev->name); ax->stats.rx_dropped++; return; } spin_lock_bh(&ax->buflock); memcpy(skb_put(skb,count), ax->rbuff, count); spin_unlock_bh(&ax->buflock); skb->protocol = ax25_type_trans(skb, ax->dev); netif_rx(skb); ax->dev->last_rx = jiffies; ax->stats.rx_packets++; ax->stats.rx_bytes += count; } static void kiss_unesc(struct mkiss *ax, unsigned char s) { switch (s) { case END: /* drop keeptest bit = VSV */ if (test_bit(AXF_KEEPTEST, &ax->flags)) clear_bit(AXF_KEEPTEST, &ax->flags); if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2)) ax_bump(ax); clear_bit(AXF_ESCAPE, &ax->flags); ax->rcount = 0; return; case ESC: set_bit(AXF_ESCAPE, &ax->flags); return; case ESC_ESC: if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) s = ESC; break; case ESC_END: if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) s = END; break; } spin_lock_bh(&ax->buflock); if (!test_bit(AXF_ERROR, &ax->flags)) { if (ax->rcount < ax->buffsize) { ax->rbuff[ax->rcount++] = s; spin_unlock_bh(&ax->buflock); return; } ax->stats.rx_over_errors++; set_bit(AXF_ERROR, &ax->flags); } spin_unlock_bh(&ax->buflock); } static int ax_set_mac_address(struct net_device *dev, void *addr) { struct sockaddr_ax25 *sa = addr; netif_tx_lock_bh(dev); memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); netif_tx_unlock_bh(dev); return 0; } /*---------------------------------------------------------------------------*/ static void ax_changedmtu(struct mkiss *ax) { struct net_device *dev = ax->dev; unsigned char *xbuff, *rbuff, *oxbuff, *orbuff; int len; len = dev->mtu * 2; /* * allow for arrival of larger UDP packets, even if we say not to * also fixes a bug in which SunOS sends 512-byte packets even with * an MSS of 128 */ if (len < 576 * 2) len = 576 * 2; xbuff = kmalloc(len + 4, GFP_ATOMIC); rbuff = kmalloc(len + 4, GFP_ATOMIC); if (xbuff == NULL || rbuff == NULL) { printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, " "MTU change cancelled.\n", ax->dev->name); dev->mtu = ax->mtu; kfree(xbuff); kfree(rbuff); return; } spin_lock_bh(&ax->buflock); oxbuff = ax->xbuff; ax->xbuff = xbuff; orbuff = ax->rbuff; ax->rbuff = rbuff; if (ax->xleft) { if (ax->xleft <= len) { memcpy(ax->xbuff, ax->xhead, ax->xleft); } else { ax->xleft = 0; ax->stats.tx_dropped++; } } ax->xhead = ax->xbuff; if (ax->rcount) { if (ax->rcount <= len) { memcpy(ax->rbuff, orbuff, ax->rcount); } else { ax->rcount = 0; ax->stats.rx_over_errors++; set_bit(AXF_ERROR, &ax->flags); } } ax->mtu = dev->mtu + 73; ax->buffsize = len; spin_unlock_bh(&ax->buflock); kfree(oxbuff); kfree(orbuff); } /* Encapsulate one AX.25 packet and stuff into a TTY queue. */ static void ax_encaps(struct net_device *dev, unsigned char *icp, int len) { struct mkiss *ax = netdev_priv(dev); unsigned char *p; int actual, count; if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */ ax_changedmtu(ax); if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */ len = ax->mtu; printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name); ax->stats.tx_dropped++; netif_start_queue(dev); return; } p = icp; spin_lock_bh(&ax->buflock); if ((*p & 0x0f) != 0) { /* Configuration Command (kissparms(1). * Protocol spec says: never append CRC. * This fixes a very old bug in the linux * kiss driver. -- dl9sau */ switch (*p & 0xff) { case 0x85: /* command from userspace especially for us, * not for delivery to the tnc */ if (len > 1) { int cmd = (p[1] & 0xff); switch(cmd) { case 3: ax->crcmode = CRC_MODE_SMACK; break; case 2: ax->crcmode = CRC_MODE_FLEX; break; case 1: ax->crcmode = CRC_MODE_NONE; break; case 0: default: ax->crcmode = CRC_MODE_SMACK_TEST; cmd = 0; } ax->crcauto = (cmd ? 0 : 1); printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd); } spin_unlock_bh(&ax->buflock); netif_start_queue(dev); return; default: count = kiss_esc(p, (unsigned char *)ax->xbuff, len); } } else { unsigned short crc; switch (ax->crcmode) { case CRC_MODE_SMACK_TEST: ax->crcmode = CRC_MODE_FLEX_TEST; printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name); // fall through case CRC_MODE_SMACK: *p |= 0x80; crc = swab16(crc16(0, p, len)); count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2); break; case CRC_MODE_FLEX_TEST: ax->crcmode = CRC_MODE_NONE; printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name); // fall through case CRC_MODE_FLEX: *p |= 0x20; crc = calc_crc_flex(p, len); count = kiss_esc_crc(p, (unsigned char *)ax->xbuff, crc, len+2); break; default: count = kiss_esc(p, (unsigned char *)ax->xbuff, len); } } spin_unlock_bh(&ax->buflock); set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); actual = ax->tty->driver->write(ax->tty, ax->xbuff, count); ax->stats.tx_packets++; ax->stats.tx_bytes += actual; ax->dev->trans_start = jiffies; ax->xleft = count - actual; ax->xhead = ax->xbuff + actual; } /* Encapsulate an AX.25 packet and kick it into a TTY queue. */ static int ax_xmit(struct sk_buff *skb, struct net_device *dev) { struct mkiss *ax = netdev_priv(dev); if (!netif_running(dev)) { printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name); return 1; } if (netif_queue_stopped(dev)) { /* * May be we must check transmitter timeout here ? * 14 Oct 1994 Dmitry Gorodchanin. */ if (time_before(jiffies, dev->trans_start + 20 * HZ)) { /* 20 sec timeout not reached */ return 1; } printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name, (ax->tty->driver->chars_in_buffer(ax->tty) || ax->xleft) ? "bad line quality" : "driver error"); ax->xleft = 0; clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); netif_start_queue(dev); } /* We were not busy, so we are now... :-) */ if (skb != NULL) { netif_stop_queue(dev); ax_encaps(dev, skb->data, skb->len); kfree_skb(skb); } return 0; } static int ax_open_dev(struct net_device *dev) { struct mkiss *ax = netdev_priv(dev); if (ax->tty == NULL) return -ENODEV; return 0; } #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) /* Return the frame type ID */ static int ax_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) { #ifdef CONFIG_INET if (type != htons(ETH_P_AX25)) return ax25_hard_header(skb, dev, type, daddr, saddr, len); #endif return 0; } static int ax_rebuild_header(struct sk_buff *skb) { #ifdef CONFIG_INET return ax25_rebuild_header(skb); #else return 0; #endif } #endif /* CONFIG_{AX25,AX25_MODULE} */ /* Open the low-level part of the AX25 channel. Easy! */ static int ax_open(struct net_device *dev) { struct mkiss *ax = netdev_priv(dev); unsigned long len; if (ax->tty == NULL) return -ENODEV; /* * Allocate the frame buffers: * * rbuff Receive buffer. * xbuff Transmit buffer. */ len = dev->mtu * 2; /* * allow for arrival of larger UDP packets, even if we say not to * also fixes a bug in which SunOS sends 512-byte packets even with * an MSS of 128 */ if (len < 576 * 2) len = 576 * 2; if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) goto norbuff; if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) goto noxbuff; ax->mtu = dev->mtu + 73; ax->buffsize = len; ax->rcount = 0; ax->xleft = 0; ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */ spin_lock_init(&ax->buflock); return 0; noxbuff: kfree(ax->rbuff); norbuff: return -ENOMEM; } /* Close the low-level part of the AX25 channel. Easy! */ static int ax_close(struct net_device *dev) { struct mkiss *ax = netdev_priv(dev); if (ax->tty) clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); netif_stop_queue(dev); return 0; } static struct net_device_stats *ax_get_stats(struct net_device *dev) { struct mkiss *ax = netdev_priv(dev); return &ax->stats; } static void ax_setup(struct net_device *dev) { /* Finish setting up the DEVICE info. */ dev->mtu = AX_MTU; dev->hard_start_xmit = ax_xmit; dev->open = ax_open_dev; dev->stop = ax_close; dev->get_stats = ax_get_stats; dev->set_mac_address = ax_set_mac_address; dev->hard_header_len = 0; dev->addr_len = 0; dev->type = ARPHRD_AX25; dev->tx_queue_len = 10; dev->hard_header = ax_header; dev->rebuild_header = ax_rebuild_header; memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); dev->flags = IFF_BROADCAST | IFF_MULTICAST; } /* * 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 mkiss *mkiss_get(struct tty_struct *tty) { struct mkiss *ax; read_lock(&disc_data_lock); ax = tty->disc_data; if (ax) atomic_inc(&ax->refcnt); read_unlock(&disc_data_lock); return ax; } static void mkiss_put(struct mkiss *ax) { if (atomic_dec_and_test(&ax->refcnt)) up(&ax->dead_sem); } static int crc_force = 0; /* Can be overridden with insmod */ static int mkiss_open(struct tty_struct *tty) { struct net_device *dev; struct mkiss *ax; int err; if (!capable(CAP_NET_ADMIN)) return -EPERM; dev = alloc_netdev(sizeof(struct mkiss), "ax%d", ax_setup); if (!dev) { err = -ENOMEM; goto out; } ax = netdev_priv(dev); ax->dev = dev; spin_lock_init(&ax->buflock); atomic_set(&ax->refcnt, 1); init_MUTEX_LOCKED(&ax->dead_sem); ax->tty = tty; tty->disc_data = ax; tty->receive_room = 65535; if (tty->driver->flush_buffer) tty->driver->flush_buffer(tty); /* Restore default settings */ dev->type = ARPHRD_AX25; /* Perform the low-level AX25 initialization. */ if ((err = ax_open(ax->dev))) { goto out_free_netdev; } if (register_netdev(dev)) goto out_free_buffers; /* after register_netdev() - because else printk smashes the kernel */ switch (crc_force) { case 3: ax->crcmode = CRC_MODE_SMACK; printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n", ax->dev->name); break; case 2: ax->crcmode = CRC_MODE_FLEX; printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n", ax->dev->name); break; case 1: ax->crcmode = CRC_MODE_NONE; printk(KERN_INFO "mkiss: %s: crc mode disabled.\n", ax->dev->name); break; case 0: /* fall through */ default: crc_force = 0; printk(KERN_INFO "mkiss: %s: crc mode is auto.\n", ax->dev->name); ax->crcmode = CRC_MODE_SMACK_TEST; } ax->crcauto = (crc_force ? 0 : 1); netif_start_queue(dev); /* Done. We have linked the TTY line to a channel. */ return 0; out_free_buffers: kfree(ax->rbuff); kfree(ax->xbuff); out_free_netdev: free_netdev(dev); out: return err; } static void mkiss_close(struct tty_struct *tty) { struct mkiss *ax; write_lock(&disc_data_lock); ax = tty->disc_data; tty->disc_data = NULL; write_unlock(&disc_data_lock); if (ax == 0) 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 (!atomic_dec_and_test(&ax->refcnt)) down(&ax->dead_sem); unregister_netdev(ax->dev); /* Free all AX25 frame buffers. */ kfree(ax->rbuff); kfree(ax->xbuff); ax->tty = NULL; } /* Perform I/O control on an active ax25 channel. */ static int mkiss_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { struct mkiss *ax = mkiss_get(tty); struct net_device *dev = ax->dev; unsigned int tmp, err; /* First make sure we're connected. */ if (ax == NULL) return -ENXIO; switch (cmd) { case SIOCGIFNAME: err = copy_to_user((void __user *) arg, ax->dev->name, strlen(ax->dev->name) + 1) ? -EFAULT : 0; break; case SIOCGIFENCAP: err = put_user(4, (int __user *) arg); break; case SIOCSIFENCAP: if (get_user(tmp, (int __user *) arg)) { err = -EFAULT; break; } ax->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 = -ENOIOCTLCMD; } mkiss_put(ax); return err; } /* * Handle the 'receiver data ready' interrupt. * This function is called by the 'tty_io' module in the kernel when * a block of data has been received, which can now be decapsulated * and sent on to the AX.25 layer for further processing. */ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) { struct mkiss *ax = mkiss_get(tty); if (!ax) return; /* * Argh! mtu change time! - costs us the packet part received * at the change */ if (ax->mtu != ax->dev->mtu + 73) ax_changedmtu(ax); /* Read the characters out of the buffer */ while (count--) { if (fp != NULL && *fp++) { if (!test_and_set_bit(AXF_ERROR, &ax->flags)) ax->stats.rx_errors++; cp++; continue; } kiss_unesc(ax, *cp++); } mkiss_put(ax); if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) && tty->driver->unthrottle) tty->driver->unthrottle(tty); } /* * Called by the driver when there's room for more data. If we have * more packets to send, we send them here. */ static void mkiss_write_wakeup(struct tty_struct *tty) { struct mkiss *ax = mkiss_get(tty); int actual; if (!ax) return; if (ax->xleft <= 0) { /* Now serial buffer is almost free & we can start * transmission of another packet */ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); netif_wake_queue(ax->dev); goto out; } actual = tty->driver->write(tty, ax->xhead, ax->xleft); ax->xleft -= actual; ax->xhead += actual; out: mkiss_put(ax); } static struct tty_ldisc ax_ldisc = { .owner = THIS_MODULE, .magic = TTY_LDISC_MAGIC, .name = "mkiss", .open = mkiss_open, .close = mkiss_close, .ioctl = mkiss_ioctl, .receive_buf = mkiss_receive_buf, .write_wakeup = mkiss_write_wakeup }; static char banner[] __initdata = KERN_INFO \ "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n"; static char msg_regfail[] __initdata = KERN_ERR \ "mkiss: can't register line discipline (err = %d)\n"; static int __init mkiss_init_driver(void) { int status; printk(banner); if ((status = tty_register_ldisc(N_AX25, &ax_ldisc)) != 0) printk(msg_regfail); return status; } static const char msg_unregfail[] __exitdata = KERN_ERR \ "mkiss: can't unregister line discipline (err = %d)\n"; static void __exit mkiss_exit_driver(void) { int ret; if ((ret = tty_unregister_ldisc(N_AX25))) printk(msg_unregfail, ret); } MODULE_AUTHOR("Ralf Baechle DL5RB <ralf@linux-mips.org>"); MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs"); module_param(crc_force, int, 0); MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]"); MODULE_LICENSE("GPL"); MODULE_ALIAS_LDISC(N_AX25); module_init(mkiss_init_driver); module_exit(mkiss_exit_driver);