[IrDA]: Kingsun KS-959 IrDA USB driver

This dongle does not follow the usb-irda specification, so it needs its own
special driver. First, it uses control URBs for data transfer, instead of
bulk or interrupt transfers; the only interrupt endpoint exposed seems to
be a dummy to prevent the interface from being rejected. Second, it uses
obfuscation and padding at the USB traffic level, for no apparent reason
other than to make reverse engineering harder (full details on obfuscation
in comments at beginning of source). Although it is advertised as a "4 Mbps
FIR dongle", it apparently loses packets at speeds greater than 57600 bps.

On plugin, this dongle reports vendor and device IDs: 0x07d0:0x4959 .

The Windows driver that is used normally to control this dongle has a
filename of KS-959.SYS .

Signed-off-by: Alex Villacís Lasso <a_villacis@palosanto.com>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 939 insertions, 0 deletions

diff --git a/drivers/net/irda/ks959-sir.c b/drivers/net/irda/ks959-sir.c
new file mode 100644
index 000000000000..407afba1a597
--- /dev/null
+++ b/drivers/net/irda/ks959-sir.c
@@ -0,0 +1,939 @@
+/*****************************************************************************
+*
+* Filename:      ks959-sir.c
+* Version:       0.1.2
+* Description:   Irda KingSun KS-959 USB Dongle
+* Status:        Experimental
+* Author:        Alex Villacís Lasso <a_villacis@palosanto.com>
+*         with help from Domen Puncer <domen@coderock.org>
+*
+*    Based on stir4200, mcs7780, kingsun-sir drivers.
+*
+*    This program is free software; you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation; either version 2 of the License.
+*
+*    This program is distributed in the hope that 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+*****************************************************************************/
+
+/*
+ * Following is my most current (2007-07-17) understanding of how the Kingsun
+ * KS-959 dongle is supposed to work. This information was deduced by
+ * reverse-engineering and examining the USB traffic captured with USBSnoopy
+ * from the WinXP driver. Feel free to update here as more of the dongle is
+ * known.
+ *
+ * My most sincere thanks must go to Domen Puncer <domen@coderock.org> for
+ * invaluable help in cracking the obfuscation and padding required for this
+ * dongle.
+ *
+ * General: This dongle exposes one interface with one interrupt IN endpoint.
+ * However, the interrupt endpoint is NOT used at all for this dongle. Instead,
+ * this dongle uses control transfers for everything, including sending and
+ * receiving the IrDA frame data. Apparently the interrupt endpoint is just a
+ * dummy to ensure the dongle has a valid interface to present to the PC.And I
+ * thought the DonShine dongle was weird... In addition, this dongle uses
+ * obfuscation (?!?!), applied at the USB level, to hide the traffic, both sent
+ * and received, from the dongle. I call it obfuscation because the XOR keying
+ * and padding required to produce an USB traffic acceptable for the dongle can
+ * not be explained by any other technical requirement.
+ *
+ * Transmission: To transmit an IrDA frame, the driver must prepare a control
+ * URB with the following as a setup packet:
+ *    bRequestType    USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE
+ *    bRequest        0x09
+ *    wValue          <length of valid data before padding, little endian>
+ *    wIndex          0x0000
+ *    wLength         <length of padded data>
+ * The payload packet must be manually wrapped and escaped (as in stir4200.c),
+ * then padded and obfuscated before being sent. Both padding and obfuscation
+ * are implemented in the procedure obfuscate_tx_buffer(). Suffice to say, the
+ * designer/programmer of the dongle used his name as a source for the
+ * obfuscation. WTF?!
+ * Apparently the dongle cannot handle payloads larger than 256 bytes. The
+ * driver has to perform fragmentation in order to send anything larger than
+ * this limit.
+ *
+ * Reception: To receive data, the driver must poll the dongle regularly (like
+ * kingsun-sir.c) with control URBs and the following as a setup packet:
+ *    bRequestType    USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE
+ *    bRequest        0x01
+ *    wValue          0x0200
+ *    wIndex          0x0000
+ *    wLength         0x0800 (size of available buffer)
+ * If there is data to be read, it will be returned as the response payload.
+ * This data is (apparently) not padded, but it is obfuscated. To de-obfuscate
+ * it, the driver must XOR every byte, in sequence, with a value that starts at
+ * 1 and is incremented with each byte processed, and then with 0x55. The value
+ * incremented with each byte processed overflows as an unsigned char. The
+ * resulting bytes form a wrapped SIR frame that is unwrapped and unescaped
+ * as in stir4200.c The incremented value is NOT reset with each frame, but is
+ * kept across the entire session with the dongle. Also, the dongle inserts an
+ * extra garbage byte with value 0x95 (after decoding) every 0xff bytes, which
+ * must be skipped.
+ *
+ * Speed change: To change the speed of the dongle, the driver prepares a
+ * control URB with the following as a setup packet:
+ *    bRequestType    USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE
+ *    bRequest        0x09
+ *    wValue          0x0200
+ *    wIndex          0x0001
+ *    wLength         0x0008 (length of the payload)
+ * The payload is a 8-byte record, apparently identical to the one used in
+ * drivers/usb/serial/cypress_m8.c to change speed:
+ *     __u32 baudSpeed;
+ *    unsigned int dataBits : 2;    // 0 - 5 bits 3 - 8 bits
+ *    unsigned int : 1;
+ *    unsigned int stopBits : 1;
+ *    unsigned int parityEnable : 1;
+ *    unsigned int parityType : 1;
+ *    unsigned int : 1;
+ *    unsigned int reset : 1;
+ *    unsigned char reserved[3];    // set to 0
+ *
+ * For now only SIR speeds have been observed with this dongle. Therefore,
+ * nothing is known on what changes (if any) must be done to frame wrapping /
+ * unwrapping for higher than SIR speeds. This driver assumes no change is
+ * necessary and announces support for all the way to 57600 bps. Although the
+ * package announces support for up to 4MBps, tests with a Sony Ericcson K300
+ * phone show corruption when receiving large frames at 115200 bps, the highest
+ * speed announced by the phone. However, transmission at 115200 bps is OK. Go
+ * figure. Since I don't know whether the phone or the dongle is at fault, max
+ * announced speed is 57600 bps until someone produces a device that can run
+ * at higher speeds with this dongle.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kref.h>
+#include <linux/usb.h>
+#include <linux/device.h>
+#include <linux/crc32.h>
+
+#include <asm/unaligned.h>
+#include <asm/byteorder.h>
+#include <asm/uaccess.h>
+
+#include <net/irda/irda.h>
+#include <net/irda/wrapper.h>
+#include <net/irda/crc.h>
+
+#define KS959_VENDOR_ID 0x07d0
+#define KS959_PRODUCT_ID 0x4959
+
+/* These are the currently known USB ids */
+static struct usb_device_id dongles[] = {
+        /* KingSun Co,Ltd  IrDA/USB Bridge */
+        {USB_DEVICE(KS959_VENDOR_ID, KS959_PRODUCT_ID)},
+        {}
+};
+
+MODULE_DEVICE_TABLE(usb, dongles);
+
+#define KINGSUN_MTT 0x07
+#define KINGSUN_REQ_RECV 0x01
+#define KINGSUN_REQ_SEND 0x09
+
+#define KINGSUN_RCV_FIFO_SIZE    2048   /* Max length we can receive */
+#define KINGSUN_SND_FIFO_SIZE    2048   /* Max packet we can send */
+#define KINGSUN_SND_PACKET_SIZE    256  /* Max packet dongle can handle */
+
+struct ks959_speedparams {
+        __le32 baudrate;        /* baud rate, little endian */
+        __u8 flags;
+        __u8 reserved[3];
+} __attribute__ ((packed));
+
+#define KS_DATA_5_BITS 0x00
+#define KS_DATA_6_BITS 0x01
+#define KS_DATA_7_BITS 0x02
+#define KS_DATA_8_BITS 0x03
+
+#define KS_STOP_BITS_1 0x00
+#define KS_STOP_BITS_2 0x08
+
+#define KS_PAR_DISABLE    0x00
+#define KS_PAR_EVEN    0x10
+#define KS_PAR_ODD    0x30
+#define KS_RESET    0x80
+
+struct ks959_cb {
+        struct usb_device *usbdev;      /* init: probe_irda */
+        struct net_device *netdev;      /* network layer */
+        struct irlap_cb *irlap; /* The link layer we are binded to */
+        struct net_device_stats stats;  /* network statistics */
+        struct qos_info qos;
+
+        struct usb_ctrlrequest *tx_setuprequest;
+        struct urb *tx_urb;
+        __u8 *tx_buf_clear;
+        unsigned int tx_buf_clear_used;
+        unsigned int tx_buf_clear_sent;
+        __u8 *tx_buf_xored;
+
+        struct usb_ctrlrequest *rx_setuprequest;
+        struct urb *rx_urb;
+        __u8 *rx_buf;
+        __u8 rx_variable_xormask;
+        iobuff_t rx_unwrap_buff;
+        struct timeval rx_time;
+
+        struct usb_ctrlrequest *speed_setuprequest;
+        struct urb *speed_urb;
+        struct ks959_speedparams speedparams;
+        unsigned int new_speed;
+
+        spinlock_t lock;
+        int receiving;
+};
+
+/* Procedure to perform the obfuscation/padding expected by the dongle
+ *
+ * buf_cleartext    (IN) Cleartext version of the IrDA frame to transmit
+ * len_cleartext    (IN) Length of the cleartext version of IrDA frame
+ * buf_xoredtext    (OUT) Obfuscated version of frame built by proc
+ * len_maxbuf        (OUT) Maximum space available at buf_xoredtext
+ *
+ * (return)         length of obfuscated frame with padding
+ *
+ * If not enough space (as indicated by len_maxbuf vs. required padding),
+ * zero is returned
+ *
+ * The value of lookup_string is actually a required portion of the algorithm.
+ * Seems the designer of the dongle wanted to state who exactly is responsible
+ * for implementing obfuscation. Send your best (or other) wishes to him ]:-)
+ */
+static unsigned int obfuscate_tx_buffer(const __u8 * buf_cleartext,
+                                        unsigned int len_cleartext,
+                                        __u8 * buf_xoredtext,
+                                        unsigned int len_maxbuf)
+{
+        unsigned int len_xoredtext;
+
+        /* Calculate required length with padding, check for necessary space */
+        len_xoredtext = ((len_cleartext + 7) & ~0x7) + 0x10;
+        if (len_xoredtext <= len_maxbuf) {
+                static const __u8 lookup_string[] = "wangshuofei19710";
+                __u8 xor_mask;
+
+                /* Unlike the WinXP driver, we *do* clear out the padding */
+                memset(buf_xoredtext, 0, len_xoredtext);
+
+                xor_mask = lookup_string[(len_cleartext & 0x0f) ^ 0x06] ^ 0x55;
+
+                while (len_cleartext-- > 0) {
+                        *buf_xoredtext++ = *buf_cleartext++ ^ xor_mask;
+                }
+        } else {
+                len_xoredtext = 0;
+        }
+        return len_xoredtext;
+}
+
+/* Callback transmission routine */
+static void ks959_speed_irq(struct urb *urb)
+{
+        /* unlink, shutdown, unplug, other nasties */
+        if (urb->status != 0) {
+                err("ks959_speed_irq: urb asynchronously failed - %d",
+                    urb->status);
+        }
+}
+
+/* Send a control request to change speed of the dongle */
+static int ks959_change_speed(struct ks959_cb *kingsun, unsigned speed)
+{
+        static unsigned int supported_speeds[] = { 2400, 9600, 19200, 38400,
+                57600, 115200, 576000, 1152000, 4000000, 0
+        };
+        int err;
+        unsigned int i;
+
+        if (kingsun->speed_setuprequest == NULL || kingsun->speed_urb == NULL)
+                return -ENOMEM;
+
+        /* Check that requested speed is among the supported ones */
+        for (i = 0; supported_speeds[i] && supported_speeds[i] != speed; i++) ;
+        if (supported_speeds[i] == 0)
+                return -EOPNOTSUPP;
+
+        memset(&(kingsun->speedparams), 0, sizeof(struct ks959_speedparams));
+        kingsun->speedparams.baudrate = cpu_to_le32(speed);
+        kingsun->speedparams.flags = KS_DATA_8_BITS;
+
+        /* speed_setuprequest pre-filled in ks959_probe */
+        usb_fill_control_urb(kingsun->speed_urb, kingsun->usbdev,
+                             usb_sndctrlpipe(kingsun->usbdev, 0),
+                             (unsigned char *)kingsun->speed_setuprequest,
+                             &(kingsun->speedparams),
+                             sizeof(struct ks959_speedparams), ks959_speed_irq,
+                             kingsun);
+        kingsun->speed_urb->status = 0;
+        err = usb_submit_urb(kingsun->speed_urb, GFP_ATOMIC);
+
+        return err;
+}
+
+/* Submit one fragment of an IrDA frame to the dongle */
+static void ks959_send_irq(struct urb *urb);
+static int ks959_submit_tx_fragment(struct ks959_cb *kingsun)
+{
+        unsigned int padlen;
+        unsigned int wraplen;
+        int ret;
+
+        /* Check whether current plaintext can produce a padded buffer that fits
+           within the range handled by the dongle */
+        wraplen = (KINGSUN_SND_PACKET_SIZE & ~0x7) - 0x10;
+        if (wraplen > kingsun->tx_buf_clear_used)
+                wraplen = kingsun->tx_buf_clear_used;
+
+        /* Perform dongle obfuscation. Also remove the portion of the frame that
+           was just obfuscated and will now be sent to the dongle. */
+        padlen = obfuscate_tx_buffer(kingsun->tx_buf_clear, wraplen,
+                                     kingsun->tx_buf_xored,
+                                     KINGSUN_SND_PACKET_SIZE);
+
+        /* Calculate how much data can be transmitted in this urb */
+        kingsun->tx_setuprequest->wValue = cpu_to_le16(wraplen);
+        kingsun->tx_setuprequest->wLength = cpu_to_le16(padlen);
+        /* Rest of the fields were filled in ks959_probe */
+        usb_fill_control_urb(kingsun->tx_urb, kingsun->usbdev,
+                             usb_sndctrlpipe(kingsun->usbdev, 0),
+                             (unsigned char *)kingsun->tx_setuprequest,
+                             kingsun->tx_buf_xored, padlen,
+                             ks959_send_irq, kingsun);
+        kingsun->tx_urb->status = 0;
+        ret = usb_submit_urb(kingsun->tx_urb, GFP_ATOMIC);
+
+        /* Remember how much data was sent, in order to update at callback */
+        kingsun->tx_buf_clear_sent = (ret == 0) ? wraplen : 0;
+        return ret;
+}
+
+/* Callback transmission routine */
+static void ks959_send_irq(struct urb *urb)
+{
+        struct ks959_cb *kingsun = urb->context;
+        struct net_device *netdev = kingsun->netdev;
+        int ret = 0;
+
+        /* in process of stopping, just drop data */
+        if (!netif_running(kingsun->netdev)) {
+                err("ks959_send_irq: Network not running!");
+                return;
+        }
+
+        /* unlink, shutdown, unplug, other nasties */
+        if (urb->status != 0) {
+                err("ks959_send_irq: urb asynchronously failed - %d",
+                    urb->status);
+                return;
+        }
+
+        if (kingsun->tx_buf_clear_used > 0) {
+                /* Update data remaining to be sent */
+                if (kingsun->tx_buf_clear_sent < kingsun->tx_buf_clear_used) {
+                        memmove(kingsun->tx_buf_clear,
+                                kingsun->tx_buf_clear +
+                                kingsun->tx_buf_clear_sent,
+                                kingsun->tx_buf_clear_used -
+                                kingsun->tx_buf_clear_sent);
+                }
+                kingsun->tx_buf_clear_used -= kingsun->tx_buf_clear_sent;
+                kingsun->tx_buf_clear_sent = 0;
+
+                if (kingsun->tx_buf_clear_used > 0) {
+                        /* There is more data to be sent */
+                        if ((ret = ks959_submit_tx_fragment(kingsun)) != 0) {
+                                err("ks959_send_irq: failed tx_urb submit: %d",
+                                    ret);
+                                switch (ret) {
+                                case -ENODEV:
+                                case -EPIPE:
+                                        break;
+                                default:
+                                        kingsun->stats.tx_errors++;
+                                        netif_start_queue(netdev);
+                                }
+                        }
+                } else {
+                        /* All data sent, send next speed && wake network queue */
+                        if (kingsun->new_speed != -1 &&
+                            cpu_to_le32(kingsun->new_speed) !=
+                            kingsun->speedparams.baudrate)
+                                ks959_change_speed(kingsun, kingsun->new_speed);
+
+                        netif_wake_queue(netdev);
+                }
+        }
+}
+
+/*
+ * Called from net/core when new frame is available.
+ */
+static int ks959_hard_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+        struct ks959_cb *kingsun;
+        unsigned int wraplen;
+        int ret = 0;
+
+        if (skb == NULL || netdev == NULL)
+                return -EINVAL;
+
+        netif_stop_queue(netdev);
+
+        /* the IRDA wrapping routines don't deal with non linear skb */
+        SKB_LINEAR_ASSERT(skb);
+
+        kingsun = netdev_priv(netdev);
+
+        spin_lock(&kingsun->lock);
+        kingsun->new_speed = irda_get_next_speed(skb);
+
+        /* Append data to the end of whatever data remains to be transmitted */
+        wraplen =
+            async_wrap_skb(skb, kingsun->tx_buf_clear, KINGSUN_SND_FIFO_SIZE);
+        kingsun->tx_buf_clear_used = wraplen;
+
+        if ((ret = ks959_submit_tx_fragment(kingsun)) != 0) {
+                err("ks959_hard_xmit: failed tx_urb submit: %d", ret);
+                switch (ret) {
+                case -ENODEV:
+                case -EPIPE:
+                        break;
+                default:
+                        kingsun->stats.tx_errors++;
+                        netif_start_queue(netdev);
+                }
+        } else {
+                kingsun->stats.tx_packets++;
+                kingsun->stats.tx_bytes += skb->len;
+
+        }
+
+        dev_kfree_skb(skb);
+        spin_unlock(&kingsun->lock);
+
+        return ret;
+}
+
+/* Receive callback function */
+static void ks959_rcv_irq(struct urb *urb)
+{
+        struct ks959_cb *kingsun = urb->context;
+        int ret;
+
+        /* in process of stopping, just drop data */
+        if (!netif_running(kingsun->netdev)) {
+                kingsun->receiving = 0;
+                return;
+        }
+
+        /* unlink, shutdown, unplug, other nasties */
+        if (urb->status != 0) {
+                err("kingsun_rcv_irq: urb asynchronously failed - %d",
+                    urb->status);
+                kingsun->receiving = 0;
+                return;
+        }
+
+        if (urb->actual_length > 0) {
+                __u8 *bytes = urb->transfer_buffer;
+                unsigned int i;
+
+                for (i = 0; i < urb->actual_length; i++) {
+                        /* De-obfuscation implemented here: variable portion of
+                           xormask is incremented, and then used with the encoded
+                           byte for the XOR. The result of the operation is used
+                           to unwrap the SIR frame. */
+                        kingsun->rx_variable_xormask++;
+                        bytes[i] =
+                            bytes[i] ^ kingsun->rx_variable_xormask ^ 0x55u;
+
+                        /* rx_variable_xormask doubles as an index counter so we
+                           can skip the byte at 0xff (wrapped around to 0).
+                         */
+                        if (kingsun->rx_variable_xormask != 0) {
+                                async_unwrap_char(kingsun->netdev,
+                                                  &kingsun->stats,
+                                                  &kingsun->rx_unwrap_buff,
+                                                  bytes[i]);
+                        }
+                }
+                kingsun->netdev->last_rx = jiffies;
+                do_gettimeofday(&kingsun->rx_time);
+                kingsun->receiving =
+                    (kingsun->rx_unwrap_buff.state != OUTSIDE_FRAME) ? 1 : 0;
+        }
+
+        /* This urb has already been filled in kingsun_net_open. Setup
+           packet must be re-filled, but it is assumed that urb keeps the
+           pointer to the initial setup packet, as well as the payload buffer.
+           Setup packet is already pre-filled at ks959_probe.
+         */
+        urb->status = 0;
+        ret = usb_submit_urb(urb, GFP_ATOMIC);
+}
+
+/*
+ * Function kingsun_net_open (dev)
+ *
+ *    Network device is taken up. Usually this is done by "ifconfig irda0 up"
+ */
+static int ks959_net_open(struct net_device *netdev)
+{
+        struct ks959_cb *kingsun = netdev_priv(netdev);
+        int err = -ENOMEM;
+        char hwname[16];
+
+        /* At this point, urbs are NULL, and skb is NULL (see kingsun_probe) */
+        kingsun->receiving = 0;
+
+        /* Initialize for SIR to copy data directly into skb.  */
+        kingsun->rx_unwrap_buff.in_frame = FALSE;
+        kingsun->rx_unwrap_buff.state = OUTSIDE_FRAME;
+        kingsun->rx_unwrap_buff.truesize = IRDA_SKB_MAX_MTU;
+        kingsun->rx_unwrap_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
+        if (!kingsun->rx_unwrap_buff.skb)
+                goto free_mem;
+
+        skb_reserve(kingsun->rx_unwrap_buff.skb, 1);
+        kingsun->rx_unwrap_buff.head = kingsun->rx_unwrap_buff.skb->data;
+        do_gettimeofday(&kingsun->rx_time);
+
+        kingsun->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!kingsun->rx_urb)
+                goto free_mem;
+
+        kingsun->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!kingsun->tx_urb)
+                goto free_mem;
+
+        kingsun->speed_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!kingsun->speed_urb)
+                goto free_mem;
+
+        /* Initialize speed for dongle */
+        kingsun->new_speed = 9600;
+        err = ks959_change_speed(kingsun, 9600);
+        if (err < 0)
+                goto free_mem;
+
+        /*
+         * Now that everything should be initialized properly,
+         * Open new IrLAP layer instance to take care of us...
+         */
+        sprintf(hwname, "usb#%d", kingsun->usbdev->devnum);
+        kingsun->irlap = irlap_open(netdev, &kingsun->qos, hwname);
+        if (!kingsun->irlap) {
+                err("ks959-sir: irlap_open failed");
+                goto free_mem;
+        }
+
+        /* Start reception. Setup request already pre-filled in ks959_probe */
+        usb_fill_control_urb(kingsun->rx_urb, kingsun->usbdev,
+                             usb_rcvctrlpipe(kingsun->usbdev, 0),
+                             (unsigned char *)kingsun->rx_setuprequest,
+                             kingsun->rx_buf, KINGSUN_RCV_FIFO_SIZE,
+                             ks959_rcv_irq, kingsun);
+        kingsun->rx_urb->status = 0;
+        err = usb_submit_urb(kingsun->rx_urb, GFP_KERNEL);
+        if (err) {
+                err("ks959-sir: first urb-submit failed: %d", err);
+                goto close_irlap;
+        }
+
+        netif_start_queue(netdev);
+
+        /* Situation at this point:
+           - all work buffers allocated
+           - urbs allocated and ready to fill
+           - max rx packet known (in max_rx)
+           - unwrap state machine initialized, in state outside of any frame
+           - receive request in progress
+           - IrLAP layer started, about to hand over packets to send
+         */
+
+        return 0;
+
+      close_irlap:
+        irlap_close(kingsun->irlap);
+      free_mem:
+        usb_free_urb(kingsun->speed_urb);
+        kingsun->speed_urb = NULL;
+        usb_free_urb(kingsun->tx_urb);
+        kingsun->tx_urb = NULL;
+        usb_free_urb(kingsun->rx_urb);
+        kingsun->rx_urb = NULL;
+        if (kingsun->rx_unwrap_buff.skb) {
+                kfree_skb(kingsun->rx_unwrap_buff.skb);
+                kingsun->rx_unwrap_buff.skb = NULL;
+                kingsun->rx_unwrap_buff.head = NULL;
+        }
+        return err;
+}
+
+/*
+ * Function kingsun_net_close (kingsun)
+ *
+ *    Network device is taken down. Usually this is done by
+ *    "ifconfig irda0 down"
+ */
+static int ks959_net_close(struct net_device *netdev)
+{
+        struct ks959_cb *kingsun = netdev_priv(netdev);
+
+        /* Stop transmit processing */
+        netif_stop_queue(netdev);
+
+        /* Mop up receive && transmit urb's */
+        usb_kill_urb(kingsun->tx_urb);
+        usb_free_urb(kingsun->tx_urb);
+        kingsun->tx_urb = NULL;
+
+        usb_kill_urb(kingsun->speed_urb);
+        usb_free_urb(kingsun->speed_urb);
+        kingsun->speed_urb = NULL;
+
+        usb_kill_urb(kingsun->rx_urb);
+        usb_free_urb(kingsun->rx_urb);
+        kingsun->rx_urb = NULL;
+
+        kfree_skb(kingsun->rx_unwrap_buff.skb);
+        kingsun->rx_unwrap_buff.skb = NULL;
+        kingsun->rx_unwrap_buff.head = NULL;
+        kingsun->rx_unwrap_buff.in_frame = FALSE;
+        kingsun->rx_unwrap_buff.state = OUTSIDE_FRAME;
+        kingsun->receiving = 0;
+
+        /* Stop and remove instance of IrLAP */
+        if (kingsun->irlap)
+                irlap_close(kingsun->irlap);
+
+        kingsun->irlap = NULL;
+
+        return 0;
+}
+
+/*
+ * IOCTLs : Extra out-of-band network commands...
+ */
+static int ks959_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
+{
+        struct if_irda_req *irq = (struct if_irda_req *)rq;
+        struct ks959_cb *kingsun = netdev_priv(netdev);
+        int ret = 0;
+
+        switch (cmd) {
+        case SIOCSBANDWIDTH:    /* Set bandwidth */
+                if (!capable(CAP_NET_ADMIN))
+                        return -EPERM;
+
+                /* Check if the device is still there */
+                if (netif_device_present(kingsun->netdev))
+                        return ks959_change_speed(kingsun, irq->ifr_baudrate);
+                break;
+
+        case SIOCSMEDIABUSY:    /* Set media busy */
+                if (!capable(CAP_NET_ADMIN))
+                        return -EPERM;
+
+                /* Check if the IrDA stack is still there */
+                if (netif_running(kingsun->netdev))
+                        irda_device_set_media_busy(kingsun->netdev, TRUE);
+                break;
+
+        case SIOCGRECEIVING:
+                /* Only approximately true */
+                irq->ifr_receiving = kingsun->receiving;
+                break;
+
+        default:
+                ret = -EOPNOTSUPP;
+        }
+
+        return ret;
+}
+
+/*
+ * Get device stats (for /proc/net/dev and ifconfig)
+ */
+static struct net_device_stats *ks959_net_get_stats(struct net_device *netdev)
+{
+        struct ks959_cb *kingsun = netdev_priv(netdev);
+        return &kingsun->stats;
+}
+
+/*
+ * This routine is called by the USB subsystem for each new device
+ * in the system. We need to check if the device is ours, and in
+ * this case start handling it.
+ */
+static int ks959_probe(struct usb_interface *intf,
+                       const struct usb_device_id *id)
+{
+        struct usb_device *dev = interface_to_usbdev(intf);
+        struct ks959_cb *kingsun = NULL;
+        struct net_device *net = NULL;
+        int ret = -ENOMEM;
+
+        /* Allocate network device container. */
+        net = alloc_irdadev(sizeof(*kingsun));
+        if (!net)
+                goto err_out1;
+
+        SET_MODULE_OWNER(net);
+        SET_NETDEV_DEV(net, &intf->dev);
+        kingsun = netdev_priv(net);
+        kingsun->netdev = net;
+        kingsun->usbdev = dev;
+        kingsun->irlap = NULL;
+        kingsun->tx_setuprequest = NULL;
+        kingsun->tx_urb = NULL;
+        kingsun->tx_buf_clear = NULL;
+        kingsun->tx_buf_xored = NULL;
+        kingsun->tx_buf_clear_used = 0;
+        kingsun->tx_buf_clear_sent = 0;
+
+        kingsun->rx_setuprequest = NULL;
+        kingsun->rx_urb = NULL;
+        kingsun->rx_buf = NULL;
+        kingsun->rx_variable_xormask = 0;
+        kingsun->rx_unwrap_buff.in_frame = FALSE;
+        kingsun->rx_unwrap_buff.state = OUTSIDE_FRAME;
+        kingsun->rx_unwrap_buff.skb = NULL;
+        kingsun->receiving = 0;
+        spin_lock_init(&kingsun->lock);
+
+        kingsun->speed_setuprequest = NULL;
+        kingsun->speed_urb = NULL;
+        kingsun->speedparams.baudrate = 0;
+
+        /* Allocate input buffer */
+        kingsun->rx_buf = kmalloc(KINGSUN_RCV_FIFO_SIZE, GFP_KERNEL);
+        if (!kingsun->rx_buf)
+                goto free_mem;
+
+        /* Allocate input setup packet */
+        kingsun->rx_setuprequest =
+            kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+        if (!kingsun->rx_setuprequest)
+                goto free_mem;
+        kingsun->rx_setuprequest->bRequestType =
+            USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        kingsun->rx_setuprequest->bRequest = KINGSUN_REQ_RECV;
+        kingsun->rx_setuprequest->wValue = cpu_to_le16(0x0200);
+        kingsun->rx_setuprequest->wIndex = 0;
+        kingsun->rx_setuprequest->wLength = cpu_to_le16(KINGSUN_RCV_FIFO_SIZE);
+
+        /* Allocate output buffer */
+        kingsun->tx_buf_clear = kmalloc(KINGSUN_SND_FIFO_SIZE, GFP_KERNEL);
+        if (!kingsun->tx_buf_clear)
+                goto free_mem;
+        kingsun->tx_buf_xored = kmalloc(KINGSUN_SND_PACKET_SIZE, GFP_KERNEL);
+        if (!kingsun->tx_buf_xored)
+                goto free_mem;
+
+        /* Allocate and initialize output setup packet */
+        kingsun->tx_setuprequest =
+            kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+        if (!kingsun->tx_setuprequest)
+                goto free_mem;
+        kingsun->tx_setuprequest->bRequestType =
+            USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        kingsun->tx_setuprequest->bRequest = KINGSUN_REQ_SEND;
+        kingsun->tx_setuprequest->wValue = 0;
+        kingsun->tx_setuprequest->wIndex = 0;
+        kingsun->tx_setuprequest->wLength = 0;
+
+        /* Allocate and initialize speed setup packet */
+        kingsun->speed_setuprequest =
+            kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+        if (!kingsun->speed_setuprequest)
+                goto free_mem;
+        kingsun->speed_setuprequest->bRequestType =
+            USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        kingsun->speed_setuprequest->bRequest = KINGSUN_REQ_SEND;
+        kingsun->speed_setuprequest->wValue = cpu_to_le16(0x0200);
+        kingsun->speed_setuprequest->wIndex = cpu_to_le16(0x0001);
+        kingsun->speed_setuprequest->wLength =
+            cpu_to_le16(sizeof(struct ks959_speedparams));
+
+        printk(KERN_INFO "KingSun KS-959 IRDA/USB found at address %d, "
+               "Vendor: %x, Product: %x\n",
+               dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
+               le16_to_cpu(dev->descriptor.idProduct));
+
+        /* Initialize QoS for this device */
+        irda_init_max_qos_capabilies(&kingsun->qos);
+
+        /* Baud rates known to be supported. Please uncomment if devices (other
+           than a SonyEriccson K300 phone) can be shown to support higher speed
+           with this dongle.
+         */
+        kingsun->qos.baud_rate.bits =
+            IR_2400 | IR_9600 | IR_19200 | IR_38400 | IR_57600;
+        kingsun->qos.min_turn_time.bits &= KINGSUN_MTT;
+        irda_qos_bits_to_value(&kingsun->qos);
+
+        /* Override the network functions we need to use */
+        net->hard_start_xmit = ks959_hard_xmit;
+        net->open = ks959_net_open;
+        net->stop = ks959_net_close;
+        net->get_stats = ks959_net_get_stats;
+        net->do_ioctl = ks959_net_ioctl;
+
+        ret = register_netdev(net);
+        if (ret != 0)
+                goto free_mem;
+
+        info("IrDA: Registered KingSun KS-959 device %s", net->name);
+
+        usb_set_intfdata(intf, kingsun);
+
+        /* Situation at this point:
+           - all work buffers allocated
+           - setup requests pre-filled
+           - urbs not allocated, set to NULL
+           - max rx packet known (is KINGSUN_FIFO_SIZE)
+           - unwrap state machine (partially) initialized, but skb == NULL
+         */
+
+        return 0;
+
+      free_mem:
+        kfree(kingsun->speed_setuprequest);
+        kfree(kingsun->tx_setuprequest);
+        kfree(kingsun->tx_buf_xored);
+        kfree(kingsun->tx_buf_clear);
+        kfree(kingsun->rx_setuprequest);
+        kfree(kingsun->rx_buf);
+        free_netdev(net);
+      err_out1:
+        return ret;
+}
+
+/*
+ * The current device is removed, the USB layer tell us to shut it down...
+ */
+static void ks959_disconnect(struct usb_interface *intf)
+{
+        struct ks959_cb *kingsun = usb_get_intfdata(intf);
+
+        if (!kingsun)
+                return;
+
+        unregister_netdev(kingsun->netdev);
+
+        /* Mop up receive && transmit urb's */
+        if (kingsun->speed_urb != NULL) {
+                usb_kill_urb(kingsun->speed_urb);
+                usb_free_urb(kingsun->speed_urb);
+                kingsun->speed_urb = NULL;
+        }
+        if (kingsun->tx_urb != NULL) {
+                usb_kill_urb(kingsun->tx_urb);
+                usb_free_urb(kingsun->tx_urb);
+                kingsun->tx_urb = NULL;
+        }
+        if (kingsun->rx_urb != NULL) {
+                usb_kill_urb(kingsun->rx_urb);
+                usb_free_urb(kingsun->rx_urb);
+                kingsun->rx_urb = NULL;
+        }
+
+        kfree(kingsun->speed_setuprequest);
+        kfree(kingsun->tx_setuprequest);
+        kfree(kingsun->tx_buf_xored);
+        kfree(kingsun->tx_buf_clear);
+        kfree(kingsun->rx_setuprequest);
+        kfree(kingsun->rx_buf);
+        free_netdev(kingsun->netdev);
+
+        usb_set_intfdata(intf, NULL);
+}
+
+#ifdef CONFIG_PM
+/* USB suspend, so power off the transmitter/receiver */
+static int ks959_suspend(struct usb_interface *intf, pm_message_t message)
+{
+        struct ks959_cb *kingsun = usb_get_intfdata(intf);
+
+        netif_device_detach(kingsun->netdev);
+        if (kingsun->speed_urb != NULL)
+                usb_kill_urb(kingsun->speed_urb);
+        if (kingsun->tx_urb != NULL)
+                usb_kill_urb(kingsun->tx_urb);
+        if (kingsun->rx_urb != NULL)
+                usb_kill_urb(kingsun->rx_urb);
+        return 0;
+}
+
+/* Coming out of suspend, so reset hardware */
+static int ks959_resume(struct usb_interface *intf)
+{
+        struct ks959_cb *kingsun = usb_get_intfdata(intf);
+
+        if (kingsun->rx_urb != NULL) {
+                /* Setup request already filled in ks959_probe */
+                usb_submit_urb(kingsun->rx_urb, GFP_KERNEL);
+        }
+        netif_device_attach(kingsun->netdev);
+
+        return 0;
+}
+#endif
+
+/*
+ * USB device callbacks
+ */
+static struct usb_driver irda_driver = {
+        .name = "ks959-sir",
+        .probe = ks959_probe,
+        .disconnect = ks959_disconnect,
+        .id_table = dongles,
+#ifdef CONFIG_PM
+        .suspend = ks959_suspend,
+        .resume = ks959_resume,
+#endif
+};
+
+/*
+ * Module insertion
+ */
+static int __init ks959_init(void)
+{
+        return usb_register(&irda_driver);
+}
+
+module_init(ks959_init);
+
+/*
+ * Module removal
+ */
+static void __exit ks959_cleanup(void)
+{
+        /* Deregister the driver and remove all pending instances */
+        usb_deregister(&irda_driver);
+}
+
+module_exit(ks959_cleanup);
+
+MODULE_AUTHOR("Alex Villacís Lasso <a_villacis@palosanto.com>");
+MODULE_DESCRIPTION("IrDA-USB Dongle Driver for KingSun KS-959");
+MODULE_LICENSE("GPL");