usb_atm.c

h内核

/******************************************************************************
 *  usb_atm.c - Generic USB xDSL driver core
 *
 *  Copyright (C) 2001, Alcatel
 *  Copyright (C) 2003, Duncan Sands, SolNegro, Josep Comas
 *  Copyright (C) 2004, David Woodhouse
 *
 *  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, or (at your option)
 *  any later version.
 *
 *  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., 59
 *  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 ******************************************************************************/

/*
 *  Written by Johan Verrept, maintained by Duncan Sands ([e-mail])
 *
 *  1.7+:	- See the check-in logs
 *
 *  1.6:	- No longer opens a connection if the firmware is not loaded
 *  		- Added support for the speedtouch 330
 *  		- Removed the limit on the number of devices
 *  		- Module now autoloads on device plugin
 *  		- Merged relevant parts of sarlib
 *  		- Replaced the kernel thread with a tasklet
 *  		- New packet transmission code
 *  		- Changed proc file contents
 *  		- Fixed all known SMP races
 *  		- Many fixes and cleanups
 *  		- Various fixes by Oliver Neukum ([e-mail])
 *
 *  1.5A:	- Version for inclusion in 2.5 series kernel
 *		- Modifications by Richard Purdie ([e-mail])
 *		- made compatible with kernel 2.5.6 onwards by changing
 *		udsl_usb_send_data_context->urb to a pointer and adding code
 *		to alloc and free it
 *		- remove_wait_queue() added to udsl_atm_processqueue_thread()
 *
 *  1.5:	- fixed memory leak when atmsar_decode_aal5 returned NULL.
 *		(reported by [e-mail])
 *
 *  1.4:	- changed the spin_lock() under interrupt to spin_lock_irqsave()
 *		- unlink all active send urbs of a vcc that is being closed.
 *
 *  1.3.1:	- added the version number
 *
 *  1.3:	- Added multiple send urb support
 *		- fixed memory leak and vcc->tx_inuse starvation bug
 *		  when not enough memory left in vcc.
 *
 *  1.2:	- Fixed race condition in udsl_usb_send_data()
 *  1.1:	- Turned off packet debugging
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/crc32.h>
#include <linux/init.h>
#include <linux/firmware.h>

#include "usb_atm.h"

#ifdef VERBOSE_DEBUG
static int udsl_print_packet(const unsigned char *data, int len);
#define PACKETDEBUG(arg...)	udsl_print_packet (arg)
#define vdbg(arg...)		dbg (arg)
#else
#define PACKETDEBUG(arg...)
#define vdbg(arg...)
#endif

#define DRIVER_AUTHOR	"Johan Verrept, Duncan Sands <[e-mail]>"
#define DRIVER_VERSION	"1.8"
#define DRIVER_DESC	"Generic USB ATM/DSL I/O, version " DRIVER_VERSION

static unsigned int num_rcv_urbs = UDSL_DEFAULT_RCV_URBS;
static unsigned int num_snd_urbs = UDSL_DEFAULT_SND_URBS;
static unsigned int num_rcv_bufs = UDSL_DEFAULT_RCV_BUFS;
static unsigned int num_snd_bufs = UDSL_DEFAULT_SND_BUFS;
static unsigned int rcv_buf_size = UDSL_DEFAULT_RCV_BUF_SIZE;
static unsigned int snd_buf_size = UDSL_DEFAULT_SND_BUF_SIZE;

module_param(num_rcv_urbs, uint, 0444);
MODULE_PARM_DESC(num_rcv_urbs,
		 "Number of urbs used for reception (range: 0-"
		 __MODULE_STRING(UDSL_MAX_RCV_URBS) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_RCV_URBS) ")");

module_param(num_snd_urbs, uint, 0444);
MODULE_PARM_DESC(num_snd_urbs,
		 "Number of urbs used for transmission (range: 0-"
		 __MODULE_STRING(UDSL_MAX_SND_URBS) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_SND_URBS) ")");

module_param(num_rcv_bufs, uint, 0444);
MODULE_PARM_DESC(num_rcv_bufs,
		 "Number of buffers used for reception (range: 0-"
		 __MODULE_STRING(UDSL_MAX_RCV_BUFS) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_RCV_BUFS) ")");

module_param(num_snd_bufs, uint, 0444);
MODULE_PARM_DESC(num_snd_bufs,
		 "Number of buffers used for transmission (range: 0-"
		 __MODULE_STRING(UDSL_MAX_SND_BUFS) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_SND_BUFS) ")");

module_param(rcv_buf_size, uint, 0444);
MODULE_PARM_DESC(rcv_buf_size,
		 "Size of the buffers used for reception (range: 0-"
		 __MODULE_STRING(UDSL_MAX_RCV_BUF_SIZE) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_RCV_BUF_SIZE) ")");

module_param(snd_buf_size, uint, 0444);
MODULE_PARM_DESC(snd_buf_size,
		 "Size of the buffers used for transmission (range: 0-"
		 __MODULE_STRING(UDSL_MAX_SND_BUF_SIZE) ", default: "
		 __MODULE_STRING(UDSL_DEFAULT_SND_BUF_SIZE) ")");

/* ATM */

static void udsl_atm_dev_close(struct atm_dev *dev);
static int udsl_atm_open(struct atm_vcc *vcc);
static void udsl_atm_close(struct atm_vcc *vcc);
static int udsl_atm_ioctl(struct atm_dev *dev, unsigned int cmd, void __user * arg);
static int udsl_atm_send(struct atm_vcc *vcc, struct sk_buff *skb);
static int udsl_atm_proc_read(struct atm_dev *atm_dev, loff_t * pos, char *page);

static struct atmdev_ops udsl_atm_devops = {
	.dev_close	= udsl_atm_dev_close,
	.open		= udsl_atm_open,
	.close		= udsl_atm_close,
	.ioctl		= udsl_atm_ioctl,
	.send		= udsl_atm_send,
	.proc_read	= udsl_atm_proc_read,
	.owner		= THIS_MODULE,
};

/***********
**  misc  **
***********/

static inline void udsl_pop(struct atm_vcc *vcc, struct sk_buff *skb)
{
	if (vcc->pop)
		vcc->pop(vcc, skb);
	else
		dev_kfree_skb(skb);
}

/*************
**  decode  **
*************/

static inline struct udsl_vcc_data *udsl_find_vcc(struct udsl_instance_data *instance,
						  short vpi, int vci)
{
	struct udsl_vcc_data *vcc;

	list_for_each_entry(vcc, &instance->vcc_list, list)
		if ((vcc->vci == vci) && (vcc->vpi == vpi))
			return vcc;
	return NULL;
}

static void udsl_extract_cells(struct udsl_instance_data *instance,
			       unsigned char *source, unsigned int howmany)
{
	struct udsl_vcc_data *cached_vcc = NULL;
	struct atm_vcc *vcc;
	struct sk_buff *sarb;
	struct udsl_vcc_data *vcc_data;
	int cached_vci = 0;
	unsigned int i;
	int pti;
	int vci;
	short cached_vpi = 0;
	short vpi;

	for (i = 0; i < howmany;
	     i++, source += ATM_CELL_SIZE + instance->rcv_padding) {
		vpi = ((source[0] & 0x0f) << 4) | (source[1] >> 4);
		vci = ((source[1] & 0x0f) << 12) | (source[2] << 4) | (source[3] >> 4);
		pti = (source[3] & 0x2) != 0;

		vdbg("udsl_extract_cells: vpi %hd, vci %d, pti %d", vpi, vci, pti);

		if (cached_vcc && (vci == cached_vci) && (vpi == cached_vpi))
			vcc_data = cached_vcc;
		else if ((vcc_data = udsl_find_vcc(instance, vpi, vci))) {
			cached_vcc = vcc_data;
			cached_vpi = vpi;
			cached_vci = vci;
		} else {
			dbg("udsl_extract_cells: unknown vpi/vci (%hd/%d)!", vpi, vci);
			continue;
		}

		vcc = vcc_data->vcc;
		sarb = vcc_data->sarb;

		if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
			dbg("udsl_extract_cells: buffer overrun (sarb->len %u, vcc: 0x%p)!", sarb->len, vcc);
			/* discard cells already received */
			skb_trim(sarb, 0);
		}

		memcpy(sarb->tail, source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
		__skb_put(sarb, ATM_CELL_PAYLOAD);

		if (pti) {
			struct sk_buff *skb;
			unsigned int length;
			unsigned int pdu_length;

			length = (source[ATM_CELL_SIZE - 6] << 8) + source[ATM_CELL_SIZE - 5];

			/* guard against overflow */
			if (length > ATM_MAX_AAL5_PDU) {
				dbg("udsl_extract_cells: bogus length %u (vcc: 0x%p)!", length, vcc);
				atomic_inc(&vcc->stats->rx_err);
				goto out;
			}

			pdu_length = UDSL_NUM_CELLS(length) * ATM_CELL_PAYLOAD;

			if (sarb->len < pdu_length) {
				dbg("udsl_extract_cells: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!", pdu_length, sarb->len, vcc);
				atomic_inc(&vcc->stats->rx_err);
				goto out;
			}

			if (crc32_be(~0, sarb->tail - pdu_length, pdu_length) != 0xc704dd7b) {
				dbg("udsl_extract_cells: packet failed crc check (vcc: 0x%p)!", vcc);
				atomic_inc(&vcc->stats->rx_err);
				goto out;
			}

			vdbg("udsl_extract_cells: got packet (length: %u, pdu_length: %u, vcc: 0x%p)", length, pdu_length, vcc);

			if (!(skb = dev_alloc_skb(length))) {
				dbg("udsl_extract_cells: no memory for skb (length: %u)!", length);
				atomic_inc(&vcc->stats->rx_drop);
				goto out;
			}

			vdbg("udsl_extract_cells: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)", skb, skb->truesize);

			if (!atm_charge(vcc, skb->truesize)) {
				dbg("udsl_extract_cells: failed atm_charge (skb->truesize: %u)!", skb->truesize);
				dev_kfree_skb(skb);
				goto out;	/* atm_charge increments rx_drop */
			}

			memcpy(skb->data, sarb->tail - pdu_length, length);
			__skb_put(skb, length);

			vdbg("udsl_extract_cells: sending skb 0x%p, skb->len %u, skb->truesize %u", skb, skb->len, skb->truesize);

			PACKETDEBUG(skb->data, skb->len);

			vcc->push(vcc, skb);

			atomic_inc(&vcc->stats->rx);
		out:
			skb_trim(sarb, 0);
		}
	}
}

/*************
**  encode  **
*************/

static inline void udsl_fill_cell_header(unsigned char *target, struct atm_vcc *vcc)
{
	target[0] = vcc->vpi >> 4;
	target[1] = (vcc->vpi << 4) | (vcc->vci >> 12);
	target[2] = vcc->vci >> 4;
	target[3] = vcc->vci << 4;
	target[4] = 0xec;
}

static const unsigned char zeros[ATM_CELL_PAYLOAD];

static void udsl_groom_skb(struct atm_vcc *vcc, struct sk_buff *skb)
{
	struct udsl_control *ctrl = UDSL_SKB(skb);
	unsigned int zero_padding;
	u32 crc;

	ctrl->atm_data.vcc = vcc;

	ctrl->num_cells = UDSL_NUM_CELLS(skb->len);
	ctrl->num_entire = skb->len / ATM_CELL_PAYLOAD;

	zero_padding = ctrl->num_cells * ATM_CELL_PAYLOAD - skb->len - ATM_AAL5_TRAILER;

	if (ctrl->num_entire + 1 < ctrl->num_cells)
		ctrl->pdu_padding = zero_padding - (ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER);
	else
		ctrl->pdu_padding = zero_padding;

	ctrl->aal5_trailer[0] = 0;	/* UU = 0 */
	ctrl->aal5_trailer[1] = 0;	/* CPI = 0 */
	ctrl->aal5_trailer[2] = skb->len >> 8;
	ctrl->aal5_trailer[3] = skb->len;

	crc = crc32_be(~0, skb->data, skb->len);
	crc = crc32_be(crc, zeros, zero_padding);
	crc = crc32_be(crc, ctrl->aal5_trailer, 4);
	crc = ~crc;

	ctrl->aal5_trailer[4] = crc >> 24;
	ctrl->aal5_trailer[5] = crc >> 16;
	ctrl->aal5_trailer[6] = crc >> 8;
	ctrl->aal5_trailer[7] = crc;
}

static unsigned int udsl_write_cells(struct udsl_instance_data *instance,
				     unsigned int howmany, struct sk_buff *skb,
				     unsigned char **target_p)
{
	struct udsl_control *ctrl = UDSL_SKB(skb);
	unsigned char *target = *target_p;
	unsigned int nc, ne, i;

	vdbg("udsl_write_cells: howmany=%u, skb->len=%d, num_cells=%u, num_entire=%u, pdu_padding=%u", howmany, skb->len, ctrl->num_cells, ctrl->num_entire, ctrl->pdu_padding);

	nc = ctrl->num_cells;
	ne = min(howmany, ctrl->num_entire);

	for (i = 0; i < ne; i++) {
		udsl_fill_cell_header(target, ctrl->atm_data.vcc);
		target += ATM_CELL_HEADER;
		memcpy(target, skb->data, ATM_CELL_PAYLOAD);
		target += ATM_CELL_PAYLOAD;
		if (instance->snd_padding) {
			memset(target, 0, instance->snd_padding);
			target += instance->snd_padding;
		}
		__skb_pull(skb, ATM_CELL_PAYLOAD);
	}

	ctrl->num_entire -= ne;

	if (!(ctrl->num_cells -= ne) || !(howmany -= ne))
		goto out;

	udsl_fill_cell_header(target, ctrl->atm_data.vcc);
	target += ATM_CELL_HEADER;
	memcpy(target, skb->data, skb->len);
	target += skb->len;
	__skb_pull(skb, skb->len);
	memset(target, 0, ctrl->pdu_padding);
	target += ctrl->pdu_padding;

	if (--ctrl->num_cells) {
		if (!--howmany) {
			ctrl->pdu_padding = ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER;
			goto out;
		}

		if (instance->snd_padding) {
			memset(target, 0, instance->snd_padding);
			target += instance->snd_padding;
		}
		udsl_fill_cell_header(target, ctrl->atm_data.vcc);
		target += ATM_CELL_HEADER;
		memset(target, 0, ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER);
		target += ATM_CELL_PAYLOAD - ATM_AAL5_TRAILER;

		--ctrl->num_cells;
		UDSL_ASSERT(!ctrl->num_cells);
	}