diff options
Diffstat (limited to 'drivers/net/hamradio/mkiss.c')
| -rw-r--r-- | drivers/net/hamradio/mkiss.c | 986 |
1 files changed, 986 insertions, 0 deletions
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c new file mode 100644 index 000000000..049264a7d --- /dev/null +++ b/drivers/net/hamradio/mkiss.c @@ -0,0 +1,986 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * 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 <linux/bitops.h> +#include <linux/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/slab.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 <linux/refcount.h> + +#include <net/ax25.h> + +#define AX_MTU 236 + +/* some arch define END as assembly function ending, just undef it */ +#undef END +/* 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 */ + + /* 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 + + refcount_t refcnt; + struct completion dead; +}; + +/*---------------------------------------------------------------------------*/ + +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 + 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->dev->stats.rx_errors++; + spin_unlock_bh(&ax->buflock); + + return; + } + if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) { + printk(KERN_INFO + "mkiss: %s: Switching 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->dev->stats.rx_errors++; + spin_unlock_bh(&ax->buflock); + return; + } + if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) { + printk(KERN_INFO + "mkiss: %s: Switching 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; + } + } + + count = ax->rcount; + + if ((skb = dev_alloc_skb(count)) == NULL) { + printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", + ax->dev->name); + ax->dev->stats.rx_dropped++; + spin_unlock_bh(&ax->buflock); + return; + } + + skb_put_data(skb, ax->rbuff, count); + skb->protocol = ax25_type_trans(skb, ax->dev); + netif_rx(skb); + ax->dev->stats.rx_packets++; + ax->dev->stats.rx_bytes += count; + spin_unlock_bh(&ax->buflock); +} + +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->dev->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); + 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 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; + dev->stats.tx_dropped++; + } + } + + ax->xhead = ax->xbuff; + + if (ax->rcount) { + if (ax->rcount <= len) { + memcpy(ax->rbuff, orbuff, ax->rcount); + } else { + ax->rcount = 0; + dev->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 ... */ + printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name); + dev->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 set to %d\n", + ax->dev->name, cmd); + } + spin_unlock_bh(&ax->buflock); + netif_start_queue(dev); + + return; + default: + count = kiss_esc(p, 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); + fallthrough; + case CRC_MODE_SMACK: + *p |= 0x80; + crc = swab16(crc16(0, p, len)); + count = kiss_esc_crc(p, 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); + fallthrough; + case CRC_MODE_FLEX: + *p |= 0x20; + crc = calc_crc_flex(p, len); + count = kiss_esc_crc(p, ax->xbuff, crc, len+2); + break; + + default: + count = kiss_esc(p, ax->xbuff, len); + } + } + spin_unlock_bh(&ax->buflock); + + set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); + actual = ax->tty->ops->write(ax->tty, ax->xbuff, count); + dev->stats.tx_packets++; + dev->stats.tx_bytes += actual; + + netif_trans_update(ax->dev); + ax->xleft = count - actual; + ax->xhead = ax->xbuff + actual; +} + +/* Encapsulate an AX.25 packet and kick it into a TTY queue. */ +static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct mkiss *ax = netdev_priv(dev); + + if (skb->protocol == htons(ETH_P_IP)) + return ax25_ip_xmit(skb); + + if (!netif_running(dev)) { + printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name); + return NETDEV_TX_BUSY; + } + + 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(dev) + 20 * HZ)) { + /* 20 sec timeout not reached */ + return NETDEV_TX_BUSY; + } + + printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name, + (tty_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... :-) */ + netif_stop_queue(dev); + ax_encaps(dev, skb->data, skb->len); + kfree_skb(skb); + + return NETDEV_TX_OK; +} + +static int ax_open_dev(struct net_device *dev) +{ + struct mkiss *ax = netdev_priv(dev); + + if (ax->tty == NULL) + return -ENODEV; + + return 0; +} + +/* 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 const struct net_device_ops ax_netdev_ops = { + .ndo_open = ax_open_dev, + .ndo_stop = ax_close, + .ndo_start_xmit = ax_xmit, + .ndo_set_mac_address = ax_set_mac_address, +}; + +static void ax_setup(struct net_device *dev) +{ + /* Finish setting up the DEVICE info. */ + dev->mtu = AX_MTU; + dev->hard_header_len = AX25_MAX_HEADER_LEN; + dev->addr_len = AX25_ADDR_LEN; + dev->type = ARPHRD_AX25; + dev->tx_queue_len = 10; + dev->header_ops = &ax25_header_ops; + dev->netdev_ops = &ax_netdev_ops; + + + 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) + refcount_inc(&ax->refcnt); + read_unlock(&disc_data_lock); + + return ax; +} + +static void mkiss_put(struct mkiss *ax) +{ + if (refcount_dec_and_test(&ax->refcnt)) + complete(&ax->dead); +} + +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; + if (tty->ops->write == NULL) + return -EOPNOTSUPP; + + dev = alloc_netdev(sizeof(struct mkiss), "ax%d", NET_NAME_UNKNOWN, + ax_setup); + if (!dev) { + err = -ENOMEM; + goto out; + } + + ax = netdev_priv(dev); + ax->dev = dev; + + spin_lock_init(&ax->buflock); + refcount_set(&ax->refcnt, 1); + init_completion(&ax->dead); + + ax->tty = tty; + tty->disc_data = ax; + tty->receive_room = 65535; + + tty_driver_flush_buffer(tty); + + /* Restore default settings */ + dev->type = ARPHRD_AX25; + + /* Perform the low-level AX25 initialization. */ + err = ax_open(ax->dev); + if (err) + goto out_free_netdev; + + err = register_netdev(dev); + if (err) + 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: + 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_irq(&disc_data_lock); + ax = tty->disc_data; + tty->disc_data = NULL; + write_unlock_irq(&disc_data_lock); + + if (!ax) + 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(&ax->refcnt)) + wait_for_completion(&ax->dead); + /* + * Halt the transmit queue so that a new transmit cannot scribble + * on our buffers + */ + netif_stop_queue(ax->dev); + + unregister_netdev(ax->dev); + + /* Free all AX25 frame buffers after unreg. */ + kfree(ax->rbuff); + kfree(ax->xbuff); + + ax->tty = NULL; + + free_netdev(ax->dev); +} + +/* 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; + unsigned int tmp, err; + + /* First make sure we're connected. */ + if (ax == NULL) + return -ENXIO; + dev = ax->dev; + + 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->dev->stats.rx_errors++; + cp++; + continue; + } + + kiss_unesc(ax, *cp++); + } + + mkiss_put(ax); + tty_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->ops->write(tty, ax->xhead, ax->xleft); + ax->xleft -= actual; + ax->xhead += actual; + +out: + mkiss_put(ax); +} + +static struct tty_ldisc_ops 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 const char banner[] __initconst = KERN_INFO \ + "mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n"; +static const char msg_regfail[] __initconst = KERN_ERR \ + "mkiss: can't register line discipline (err = %d)\n"; + +static int __init mkiss_init_driver(void) +{ + int status; + + printk(banner); + + status = tty_register_ldisc(N_AX25, &ax_ldisc); + if (status != 0) + printk(msg_regfail, status); + + return status; +} + +static const char msg_unregfail[] = 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); |