--- /dev/null
+/*
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * 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 <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/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/compat.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 */
+
+ /* 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->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;
+ }
+
+ memcpy(skb_put(skb,count), 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 ... */
+ len = ax->mtu;
+ 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 %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, 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, 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, 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;
+
+ 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 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 + 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 = 0;
+ dev->addr_len = 0;
+ 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)
+ 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;
+ 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);
+ atomic_set(&ax->refcnt, 1);
+ sema_init(&ax->dead_sem, 0);
+
+ 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. */
+ 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_bh(&disc_data_lock);
+ ax = tty->disc_data;
+ tty->disc_data = NULL;
+ write_unlock_bh(&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 (!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;
+ 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;
+}
+
+#ifdef CONFIG_COMPAT
+static long mkiss_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 mkiss_ioctl(tty, file, cmd,
+ (unsigned long)compat_ptr(arg));
+ }
+
+ return -ENOIOCTLCMD;
+}
+#endif
+
+/*
+ * 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,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = mkiss_compat_ioctl,
+#endif
+ .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);
Code Review / kvmfornfv.git / blobdiff