text: /*
   * The USB Monitor, inspired by Dave Harding's USBMon.
   *
   * This is a binary format reader.
   *
   * Copyright (C) 2006 Paolo Abeni (paolo.abeni@email.it)
   * Copyright (C) 2006,2007 Pete Zaitcev (zaitcev@redhat.com)
   */
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/fs.h>
  #include <linux/cdev.h>
  #include <linux/usb.h>
  #include <linux/poll.h>
  #include <linux/compat.h>
  #include <linux/mm.h>
  #include <linux/smp_lock.h>
  #include <linux/scatterlist.h>
  #include <linux/slab.h>
  
  #include <asm/uaccess.h>
  
  #include "usb_mon.h"
  
  /*
   * Defined by USB 2.0 clause 9.3, table 9.2.
   */
  #define SETUP_LEN  8
  
  /* ioctl macros */
  #define MON_IOC_MAGIC 0x92
  
  #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
  /* #2 used to be MON_IOCX_URB, removed before it got into Linus tree */
  #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
  #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
  #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
  #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
  #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
  #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
  /* #9 was MON_IOCT_SETAPI */
  #define MON_IOCX_GETX   _IOW(MON_IOC_MAGIC, 10, struct mon_bin_get)
  
  #ifdef CONFIG_COMPAT
  #define MON_IOCX_GET32 _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get32)
  #define MON_IOCX_MFETCH32 _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch32)
  #define MON_IOCX_GETX32   _IOW(MON_IOC_MAGIC, 10, struct mon_bin_get32)
  #endif
  
  /*
   * Some architectures have enormous basic pages (16KB for ia64, 64KB for ppc).
   * But it's all right. Just use a simple way to make sure the chunk is never
   * smaller than a page.
   *
   * N.B. An application does not know our chunk size.
   *
   * Woops, get_zeroed_page() returns a single page. I guess we're stuck with
   * page-sized chunks for the time being.
   */
  #define CHUNK_SIZE   PAGE_SIZE
  #define CHUNK_ALIGN(x)   (((x)+CHUNK_SIZE-1) & ~(CHUNK_SIZE-1))
  
  /*
   * The magic limit was calculated so that it allows the monitoring
   * application to pick data once in two ticks. This way, another application,
   * which presumably drives the bus, gets to hog CPU, yet we collect our data.
   * If HZ is 100, a 480 mbit/s bus drives 614 KB every jiffy. USB has an
   * enormous overhead built into the bus protocol, so we need about 1000 KB.
   *
   * This is still too much for most cases, where we just snoop a few
   * descriptor fetches for enumeration. So, the default is a "reasonable"
   * amount for systems with HZ=250 and incomplete bus saturation.
   *
   * XXX What about multi-megabyte URBs which take minutes to transfer?
   */
  #define BUFF_MAX  CHUNK_ALIGN(1200*1024)
  #define BUFF_DFL   CHUNK_ALIGN(300*1024)
  #define BUFF_MIN     CHUNK_ALIGN(8*1024)
  
  /*
   * The per-event API header (2 per URB).
   *
   * This structure is seen in userland as defined by the documentation.
   */
  struct mon_bin_hdr {
  	u64 id;			/* URB ID - from submission to callback */
  	unsigned char type;	/* Same as in text API; extensible. */
  	unsigned char xfer_type;	/* ISO, Intr, Control, Bulk */
  	unsigned char epnum;	/* Endpoint number and transfer direction */
  	unsigned char devnum;	/* Device address */
  	unsigned short busnum;	/* Bus number */
  	char flag_setup;
  	char flag_data;
  	s64 ts_sec;		/* gettimeofday */
  	s32 ts_usec;		/* gettimeofday */
  	int status;
  	unsigned int len_urb;	/* Length of data (submitted or actual) */
  	unsigned int len_cap;	/* Delivered length */
  	union {
  		unsigned char setup[SETUP_LEN];	/* Only for Control S-type */
  		struct iso_rec {
  			int error_count;
  			int numdesc;
  		} iso;
  	} s;
  	int interval;
  	int start_frame;
  	unsigned int xfer_flags;
  	unsigned int ndesc;	/* Actual number of ISO descriptors */
  };
  
  /*
   * ISO vector, packed into the head of data stream.
   * This has to take 16 bytes to make sure that the end of buffer
   * wrap is not happening in the middle of a descriptor.
   */
  struct mon_bin_isodesc {
  	int          iso_status;
  	unsigned int iso_off;
  	unsigned int iso_len;
  	u32 _pad;
  };
  
  /* per file statistic */
  struct mon_bin_stats {
  	u32 queued;
  	u32 dropped;
  };
  
  struct mon_bin_get {
  	struct mon_bin_hdr __user *hdr;	/* Can be 48 bytes or 64. */
  	void __user *data;
  	size_t alloc;		/* Length of data (can be zero) */
  };
  
  struct mon_bin_mfetch {
  	u32 __user *offvec;	/* Vector of events fetched */
  	u32 nfetch;		/* Number of events to fetch (out: fetched) */
  	u32 nflush;		/* Number of events to flush */
  };
  
  #ifdef CONFIG_COMPAT
  struct mon_bin_get32 {
  	u32 hdr32;
  	u32 data32;
  	u32 alloc32;
  };
  
  struct mon_bin_mfetch32 {
          u32 offvec32;
          u32 nfetch32;
          u32 nflush32;
  };
  #endif
  
  /* Having these two values same prevents wrapping of the mon_bin_hdr */
  #define PKT_ALIGN   64
  #define PKT_SIZE    64
  
  #define PKT_SZ_API0 48	/* API 0 (2.6.20) size */
  #define PKT_SZ_API1 64	/* API 1 size: extra fields */
  
  #define ISODESC_MAX   128	/* Same number as usbfs allows, 2048 bytes. */
  
  /* max number of USB bus supported */
  #define MON_BIN_MAX_MINOR 128
  
  /*
   * The buffer: map of used pages.
   */
  struct mon_pgmap {
  	struct page *pg;
  	unsigned char *ptr;	/* XXX just use page_to_virt everywhere? */
  };
  
  /*
   * This gets associated with an open file struct.
   */
  struct mon_reader_bin {
  	/* The buffer: one per open. */
  	spinlock_t b_lock;		/* Protect b_cnt, b_in */
  	unsigned int b_size;		/* Current size of the buffer - bytes */
  	unsigned int b_cnt;		/* Bytes used */
  	unsigned int b_in, b_out;	/* Offsets into buffer - bytes */
  	unsigned int b_read;		/* Amount of read data in curr. pkt. */
  	struct mon_pgmap *b_vec;	/* The map array */
  	wait_queue_head_t b_wait;	/* Wait for data here */
  
  	struct mutex fetch_lock;	/* Protect b_read, b_out */
  	int mmap_active;
  
  	/* A list of these is needed for "bus 0". Some time later. */
  	struct mon_reader r;
  
  	/* Stats */
  	unsigned int cnt_lost;
  };
  
  static inline struct mon_bin_hdr *MON_OFF2HDR(const struct mon_reader_bin *rp,
      unsigned int offset)
  {
  	return (struct mon_bin_hdr *)
  	    (rp->b_vec[offset / CHUNK_SIZE].ptr + offset % CHUNK_SIZE);
  }
  
  #define MON_RING_EMPTY(rp)	((rp)->b_cnt == 0)
  
  static unsigned char xfer_to_pipe[4] = {
  	PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
  };
  
  static struct class *mon_bin_class;
  static dev_t mon_bin_dev0;
  static struct cdev mon_bin_cdev;
  
  static void mon_buff_area_fill(const struct mon_reader_bin *rp,
      unsigned int offset, unsigned int size);
  static int mon_bin_wait_event(struct file *file, struct mon_reader_bin *rp);
  static int mon_alloc_buff(struct mon_pgmap *map, int npages);
  static void mon_free_buff(struct mon_pgmap *map, int npages);
  
  /*
   * This is a "chunked memcpy". It does not manipulate any counters.
   */
  static unsigned int mon_copy_to_buff(const struct mon_reader_bin *this,
      unsigned int off, const unsigned char *from, unsigned int length)
  {
  	unsigned int step_len;
  	unsigned char *buf;
  	unsigned int in_page;
  
  	while (length) {
  		/*
  		 * Determine step_len.
  		 */
  		step_len = length;
  		in_page = CHUNK_SIZE - (off & (CHUNK_SIZE-1));
  		if (in_page < step_len)
  			step_len = in_page;
  
  		/*
  		 * Copy data and advance pointers.
  		 */
  		buf = this->b_vec[off / CHUNK_SIZE].ptr + off % CHUNK_SIZE;
  		memcpy(buf, from, step_len);
  		if ((off += step_len) >= this->b_size) off = 0;
  		from += step_len;
  		length -= step_len;
  	}
  	return off;
  }
  
  /*
   * This is a little worse than the above because it's "chunked copy_to_user".
   * The return value is an error code, not an offset.
   */
  static int copy_from_buf(const struct mon_reader_bin *this, unsigned int off,
      char __user *to, int length)
  {
  	unsigned int step_len;
  	unsigned char *buf;
  	unsigned int in_page;
  
  	while (length) {
  		/*
  		 * Determine step_len.
  		 */
  		step_len = length;
  		in_page = CHUNK_SIZE - (off & (CHUNK_SIZE-1));
  		if (in_page < step_len)
  			step_len = in_page;
  
  		/*
  		 * Copy data and advance pointers.
  		 */
  		buf = this->b_vec[off / CHUNK_SIZE].ptr + off % CHUNK_SIZE;
  		if (copy_to_user(to, buf, step_len))
  			return -EINVAL;
  		if ((off += step_len) >= this->b_size) off = 0;
  		to += step_len;
  		length -= step_len;
  	}
  	return 0;
  }
  
  /*
   * Allocate an (aligned) area in the buffer.
   * This is called under b_lock.
   * Returns ~0 on failure.
   */
  static unsigned int mon_buff_area_alloc(struct mon_reader_bin *rp,
      unsigned int size)
  {
  	unsigned int offset;
  
  	size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  	if (rp->b_cnt + size > rp->b_size)
  		return ~0;
  	offset = rp->b_in;
  	rp->b_cnt += size;
  	if ((rp->b_in += size) >= rp->b_size)
  		rp->b_in -= rp->b_size;
  	return offset;
  }
  
  /*
   * This is the same thing as mon_buff_area_alloc, only it does not allow
   * buffers to wrap. This is needed by applications which pass references
   * into mmap-ed buffers up their stacks (libpcap can do that).
   *
   * Currently, we always have the header stuck with the data, although
   * it is not strictly speaking necessary.
   *
   * When a buffer would wrap, we place a filler packet to mark the space.
   */
  static unsigned int mon_buff_area_alloc_contiguous(struct mon_reader_bin *rp,
      unsigned int size)
  {
  	unsigned int offset;
  	unsigned int fill_size;
  
  	size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  	if (rp->b_cnt + size > rp->b_size)
  		return ~0;
  	if (rp->b_in + size > rp->b_size) {
  		/*
  		 * This would wrap. Find if we still have space after
  		 * skipping to the end of the buffer. If we do, place
  		 * a filler packet and allocate a new packet.
  		 */
  		fill_size = rp->b_size - rp->b_in;
  		if (rp->b_cnt + size + fill_size > rp->b_size)
  			return ~0;
  		mon_buff_area_fill(rp, rp->b_in, fill_size);
  
  		offset = 0;
  		rp->b_in = size;
  		rp->b_cnt += size + fill_size;
  	} else if (rp->b_in + size == rp->b_size) {
  		offset = rp->b_in;
  		rp->b_in = 0;
  		rp->b_cnt += size;
  	} else {
  		offset = rp->b_in;
  		rp->b_in += size;
  		rp->b_cnt += size;
  	}
  	return offset;
  }
  
  /*
   * Return a few (kilo-)bytes to the head of the buffer.
   * This is used if a data fetch fails.
   */
  static void mon_buff_area_shrink(struct mon_reader_bin *rp, unsigned int size)
  {
  
  	/* size &= ~(PKT_ALIGN-1);  -- we're called with aligned size */
  	rp->b_cnt -= size;
  	if (rp->b_in < size)
  		rp->b_in += rp->b_size;
  	rp->b_in -= size;
  }
  
  /*
   * This has to be called under both b_lock and fetch_lock, because
   * it accesses both b_cnt and b_out.
   */
  static void mon_buff_area_free(struct mon_reader_bin *rp, unsigned int size)
  {
  
  	size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  	rp->b_cnt -= size;
  	if ((rp->b_out += size) >= rp->b_size)
  		rp->b_out -= rp->b_size;
  }
  
  static void mon_buff_area_fill(const struct mon_reader_bin *rp,
      unsigned int offset, unsigned int size)
  {
  	struct mon_bin_hdr *ep;
  
  	ep = MON_OFF2HDR(rp, offset);
  	memset(ep, 0, PKT_SIZE);
  	ep->type = '@';
  	ep->len_cap = size - PKT_SIZE;
  }
  
  static inline char mon_bin_get_setup(unsigned char *setupb,
      const struct urb *urb, char ev_type)
  {
  
  	if (urb->setup_packet == NULL)
  		return 'Z';
  	memcpy(setupb, urb->setup_packet, SETUP_LEN);
  	return 0;
  }
  
  static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
      unsigned int offset, struct urb *urb, unsigned int length,
      char *flag)
  {
  	int i;
  	struct scatterlist *sg;
  	unsigned int this_len;
  
  	*flag = 0;
  	if (urb->num_sgs == 0) {
  		if (urb->transfer_buffer == NULL) {
  			*flag = 'Z';
  			return length;
  		}
  		mon_copy_to_buff(rp, offset, urb->transfer_buffer, length);
  		length = 0;
  
  	} else {
  		/* If IOMMU coalescing occurred, we cannot trust sg_page */
  		if (urb->transfer_flags & URB_DMA_SG_COMBINED) {
  			*flag = 'D';
  			return length;
  		}
  
  		/* Copy up to the first non-addressable segment */
  		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
  			if (length == 0 || PageHighMem(sg_page(sg)))
  				break;
  			this_len = min_t(unsigned int, sg->length, length);
  			offset = mon_copy_to_buff(rp, offset, sg_virt(sg),
  					this_len);
  			length -= this_len;
  		}
  		if (i == 0)
  			*flag = 'D';
  	}
  
  	return length;
  }
  
  static void mon_bin_get_isodesc(const struct mon_reader_bin *rp,
      unsigned int offset, struct urb *urb, char ev_type, unsigned int ndesc)
  {
  	struct mon_bin_isodesc *dp;
  	struct usb_iso_packet_descriptor *fp;
  
  	fp = urb->iso_frame_desc;
  	while (ndesc-- != 0) {
  		dp = (struct mon_bin_isodesc *)
  		    (rp->b_vec[offset / CHUNK_SIZE].ptr + offset % CHUNK_SIZE);
  		dp->iso_status = fp->status;
  		dp->iso_off = fp->offset;
  		dp->iso_len = (ev_type == 'S') ? fp->length : fp->actual_length;
  		dp->_pad = 0;
  		if ((offset += sizeof(struct mon_bin_isodesc)) >= rp->b_size)
  			offset = 0;
  		fp++;
  	}
  }
  
  static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
      char ev_type, int status)
  {
  	const struct usb_endpoint_descriptor *epd = &urb->ep->desc;
  	struct timeval ts;
  	unsigned long flags;
  	unsigned int urb_length;
  	unsigned int offset;
  	unsigned int length;
  	unsigned int delta;
  	unsigned int ndesc, lendesc;
  	unsigned char dir;
  	struct mon_bin_hdr *ep;
  	char data_tag = 0;
  
  	do_gettimeofday(&ts);
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  
  	/*
  	 * Find the maximum allowable length, then allocate space.
  	 */
  	if (usb_endpoint_xfer_isoc(epd)) {
  		if (urb->number_of_packets < 0) {
  			ndesc = 0;
  		} else if (urb->number_of_packets >= ISODESC_MAX) {
  			ndesc = ISODESC_MAX;
  		} else {
  			ndesc = urb->number_of_packets;
  		}
  	} else {
  		ndesc = 0;
  	}
  	lendesc = ndesc*sizeof(struct mon_bin_isodesc);
  
  	urb_length = (ev_type == 'S') ?
  	    urb->transfer_buffer_length : urb->actual_length;
  	length = urb_length;
  
  	if (length >= rp->b_size/5)
  		length = rp->b_size/5;
  
  	if (usb_urb_dir_in(urb)) {
  		if (ev_type == 'S') {
  			length = 0;
  			data_tag = '<';
  		}
  		/* Cannot rely on endpoint number in case of control ep.0 */
  		dir = USB_DIR_IN;
  	} else {
  		if (ev_type == 'C') {
  			length = 0;
  			data_tag = '>';
  		}
  		dir = 0;
  	}
  
  	if (rp->mmap_active) {
  		offset = mon_buff_area_alloc_contiguous(rp,
  						 length + PKT_SIZE + lendesc);
  	} else {
  		offset = mon_buff_area_alloc(rp, length + PKT_SIZE + lendesc);
  	}
  	if (offset == ~0) {
  		rp->cnt_lost++;
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		return;
  	}
  
  	ep = MON_OFF2HDR(rp, offset);
  	if ((offset += PKT_SIZE) >= rp->b_size) offset = 0;
  
  	/*
  	 * Fill the allocated area.
  	 */
  	memset(ep, 0, PKT_SIZE);
  	ep->type = ev_type;
  	ep->xfer_type = xfer_to_pipe[usb_endpoint_type(epd)];
  	ep->epnum = dir | usb_endpoint_num(epd);
  	ep->devnum = urb->dev->devnum;
  	ep->busnum = urb->dev->bus->busnum;
  	ep->id = (unsigned long) urb;
  	ep->ts_sec = ts.tv_sec;
  	ep->ts_usec = ts.tv_usec;
  	ep->status = status;
  	ep->len_urb = urb_length;
  	ep->len_cap = length + lendesc;
  	ep->xfer_flags = urb->transfer_flags;
  
  	if (usb_endpoint_xfer_int(epd)) {
  		ep->interval = urb->interval;
  	} else if (usb_endpoint_xfer_isoc(epd)) {
  		ep->interval = urb->interval;
  		ep->start_frame = urb->start_frame;
  		ep->s.iso.error_count = urb->error_count;
  		ep->s.iso.numdesc = urb->number_of_packets;
  	}
  
  	if (usb_endpoint_xfer_control(epd) && ev_type == 'S') {
  		ep->flag_setup = mon_bin_get_setup(ep->s.setup, urb, ev_type);
  	} else {
  		ep->flag_setup = '-';
  	}
  
  	if (ndesc != 0) {
  		ep->ndesc = ndesc;
  		mon_bin_get_isodesc(rp, offset, urb, ev_type, ndesc);
  		if ((offset += lendesc) >= rp->b_size)
  			offset -= rp->b_size;
  	}
  
  	if (length != 0) {
  		length = mon_bin_get_data(rp, offset, urb, length,
  				&ep->flag_data);
  		if (length > 0) {
  			delta = (ep->len_cap + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  			ep->len_cap -= length;
  			delta -= (ep->len_cap + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  			mon_buff_area_shrink(rp, delta);
  		}
  	} else {
  		ep->flag_data = data_tag;
  	}
  
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  
  	wake_up(&rp->b_wait);
  }
  
  static void mon_bin_submit(void *data, struct urb *urb)
  {
  	struct mon_reader_bin *rp = data;
  	mon_bin_event(rp, urb, 'S', -EINPROGRESS);
  }
  
  static void mon_bin_complete(void *data, struct urb *urb, int status)
  {
  	struct mon_reader_bin *rp = data;
  	mon_bin_event(rp, urb, 'C', status);
  }
  
  static void mon_bin_error(void *data, struct urb *urb, int error)
  {
  	struct mon_reader_bin *rp = data;
  	struct timeval ts;
  	unsigned long flags;
  	unsigned int offset;
  	struct mon_bin_hdr *ep;
  
  	do_gettimeofday(&ts);
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  
  	offset = mon_buff_area_alloc(rp, PKT_SIZE);
  	if (offset == ~0) {
  		/* Not incrementing cnt_lost. Just because. */
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		return;
  	}
  
  	ep = MON_OFF2HDR(rp, offset);
  
  	memset(ep, 0, PKT_SIZE);
  	ep->type = 'E';
  	ep->xfer_type = xfer_to_pipe[usb_endpoint_type(&urb->ep->desc)];
  	ep->epnum = usb_urb_dir_in(urb) ? USB_DIR_IN : 0;
  	ep->epnum |= usb_endpoint_num(&urb->ep->desc);
  	ep->devnum = urb->dev->devnum;
  	ep->busnum = urb->dev->bus->busnum;
  	ep->id = (unsigned long) urb;
  	ep->ts_sec = ts.tv_sec;
  	ep->ts_usec = ts.tv_usec;
  	ep->status = error;
  
  	ep->flag_setup = '-';
  	ep->flag_data = 'E';
  
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  
  	wake_up(&rp->b_wait);
  }
  
  static int mon_bin_open(struct inode *inode, struct file *file)
  {
  	struct mon_bus *mbus;
  	struct mon_reader_bin *rp;
  	size_t size;
  	int rc;
  
  	mutex_lock(&mon_lock);
  	if ((mbus = mon_bus_lookup(iminor(inode))) == NULL) {
  		mutex_unlock(&mon_lock);
  		return -ENODEV;
  	}
  	if (mbus != &mon_bus0 && mbus->u_bus == NULL) {
  		printk(KERN_ERR TAG ": consistency error on open\n");
  		mutex_unlock(&mon_lock);
  		return -ENODEV;
  	}
  
  	rp = kzalloc(sizeof(struct mon_reader_bin), GFP_KERNEL);
  	if (rp == NULL) {
  		rc = -ENOMEM;
  		goto err_alloc;
  	}
  	spin_lock_init(&rp->b_lock);
  	init_waitqueue_head(&rp->b_wait);
  	mutex_init(&rp->fetch_lock);
  	rp->b_size = BUFF_DFL;
  
  	size = sizeof(struct mon_pgmap) * (rp->b_size/CHUNK_SIZE);
  	if ((rp->b_vec = kzalloc(size, GFP_KERNEL)) == NULL) {
  		rc = -ENOMEM;
  		goto err_allocvec;
  	}
  
  	if ((rc = mon_alloc_buff(rp->b_vec, rp->b_size/CHUNK_SIZE)) < 0)
  		goto err_allocbuff;
  
  	rp->r.m_bus = mbus;
  	rp->r.r_data = rp;
  	rp->r.rnf_submit = mon_bin_submit;
  	rp->r.rnf_error = mon_bin_error;
  	rp->r.rnf_complete = mon_bin_complete;
  
  	mon_reader_add(mbus, &rp->r);
  
  	file->private_data = rp;
  	mutex_unlock(&mon_lock);
  	return 0;
  
  err_allocbuff:
  	kfree(rp->b_vec);
  err_allocvec:
  	kfree(rp);
  err_alloc:
  	mutex_unlock(&mon_lock);
  	return rc;
  }
  
  /*
   * Extract an event from buffer and copy it to user space.
   * Wait if there is no event ready.
   * Returns zero or error.
   */
  static int mon_bin_get_event(struct file *file, struct mon_reader_bin *rp,
      struct mon_bin_hdr __user *hdr, unsigned int hdrbytes,
      void __user *data, unsigned int nbytes)
  {
  	unsigned long flags;
  	struct mon_bin_hdr *ep;
  	size_t step_len;
  	unsigned int offset;
  	int rc;
  
  	mutex_lock(&rp->fetch_lock);
  
  	if ((rc = mon_bin_wait_event(file, rp)) < 0) {
  		mutex_unlock(&rp->fetch_lock);
  		return rc;
  	}
  
  	ep = MON_OFF2HDR(rp, rp->b_out);
  
  	if (copy_to_user(hdr, ep, hdrbytes)) {
  		mutex_unlock(&rp->fetch_lock);
  		return -EFAULT;
  	}
  
  	step_len = min(ep->len_cap, nbytes);
  	if ((offset = rp->b_out + PKT_SIZE) >= rp->b_size) offset = 0;
  
  	if (copy_from_buf(rp, offset, data, step_len)) {
  		mutex_unlock(&rp->fetch_lock);
  		return -EFAULT;
  	}
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  	mon_buff_area_free(rp, PKT_SIZE + ep->len_cap);
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  	rp->b_read = 0;
  
  	mutex_unlock(&rp->fetch_lock);
  	return 0;
  }
  
  static int mon_bin_release(struct inode *inode, struct file *file)
  {
  	struct mon_reader_bin *rp = file->private_data;
  	struct mon_bus* mbus = rp->r.m_bus;
  
  	mutex_lock(&mon_lock);
  
  	if (mbus->nreaders <= 0) {
  		printk(KERN_ERR TAG ": consistency error on close\n");
  		mutex_unlock(&mon_lock);
  		return 0;
  	}
  	mon_reader_del(mbus, &rp->r);
  
  	mon_free_buff(rp->b_vec, rp->b_size/CHUNK_SIZE);
  	kfree(rp->b_vec);
  	kfree(rp);
  
  	mutex_unlock(&mon_lock);
  	return 0;
  }
  
  static ssize_t mon_bin_read(struct file *file, char __user *buf,
      size_t nbytes, loff_t *ppos)
  {
  	struct mon_reader_bin *rp = file->private_data;
  	unsigned int hdrbytes = PKT_SZ_API0;
  	unsigned long flags;
  	struct mon_bin_hdr *ep;
  	unsigned int offset;
  	size_t step_len;
  	char *ptr;
  	ssize_t done = 0;
  	int rc;
  
  	mutex_lock(&rp->fetch_lock);
  
  	if ((rc = mon_bin_wait_event(file, rp)) < 0) {
  		mutex_unlock(&rp->fetch_lock);
  		return rc;
  	}
  
  	ep = MON_OFF2HDR(rp, rp->b_out);
  
  	if (rp->b_read < hdrbytes) {
  		step_len = min(nbytes, (size_t)(hdrbytes - rp->b_read));
  		ptr = ((char *)ep) + rp->b_read;
  		if (step_len && copy_to_user(buf, ptr, step_len)) {
  			mutex_unlock(&rp->fetch_lock);
  			return -EFAULT;
  		}
  		nbytes -= step_len;
  		buf += step_len;
  		rp->b_read += step_len;
  		done += step_len;
  	}
  
  	if (rp->b_read >= hdrbytes) {
  		step_len = ep->len_cap;
  		step_len -= rp->b_read - hdrbytes;
  		if (step_len > nbytes)
  			step_len = nbytes;
  		offset = rp->b_out + PKT_SIZE;
  		offset += rp->b_read - hdrbytes;
  		if (offset >= rp->b_size)
  			offset -= rp->b_size;
  		if (copy_from_buf(rp, offset, buf, step_len)) {
  			mutex_unlock(&rp->fetch_lock);
  			return -EFAULT;
  		}
  		nbytes -= step_len;
  		buf += step_len;
  		rp->b_read += step_len;
  		done += step_len;
  	}
  
  	/*
  	 * Check if whole packet was read, and if so, jump to the next one.
  	 */
  	if (rp->b_read >= hdrbytes + ep->len_cap) {
  		spin_lock_irqsave(&rp->b_lock, flags);
  		mon_buff_area_free(rp, PKT_SIZE + ep->len_cap);
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		rp->b_read = 0;
  	}
  
  	mutex_unlock(&rp->fetch_lock);
  	return done;
  }
  
  /*
   * Remove at most nevents from chunked buffer.
   * Returns the number of removed events.
   */
  static int mon_bin_flush(struct mon_reader_bin *rp, unsigned nevents)
  {
  	unsigned long flags;
  	struct mon_bin_hdr *ep;
  	int i;
  
  	mutex_lock(&rp->fetch_lock);
  	spin_lock_irqsave(&rp->b_lock, flags);
  	for (i = 0; i < nevents; ++i) {
  		if (MON_RING_EMPTY(rp))
  			break;
  
  		ep = MON_OFF2HDR(rp, rp->b_out);
  		mon_buff_area_free(rp, PKT_SIZE + ep->len_cap);
  	}
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  	rp->b_read = 0;
  	mutex_unlock(&rp->fetch_lock);
  	return i;
  }
  
  /*
   * Fetch at most max event offsets into the buffer and put them into vec.
   * The events are usually freed later with mon_bin_flush.
   * Return the effective number of events fetched.
   */
  static int mon_bin_fetch(struct file *file, struct mon_reader_bin *rp,
      u32 __user *vec, unsigned int max)
  {
  	unsigned int cur_out;
  	unsigned int bytes, avail;
  	unsigned int size;
  	unsigned int nevents;
  	struct mon_bin_hdr *ep;
  	unsigned long flags;
  	int rc;
  
  	mutex_lock(&rp->fetch_lock);
  
  	if ((rc = mon_bin_wait_event(file, rp)) < 0) {
  		mutex_unlock(&rp->fetch_lock);
  		return rc;
  	}
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  	avail = rp->b_cnt;
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  
  	cur_out = rp->b_out;
  	nevents = 0;
  	bytes = 0;
  	while (bytes < avail) {
  		if (nevents >= max)
  			break;
  
  		ep = MON_OFF2HDR(rp, cur_out);
  		if (put_user(cur_out, &vec[nevents])) {
  			mutex_unlock(&rp->fetch_lock);
  			return -EFAULT;
  		}
  
  		nevents++;
  		size = ep->len_cap + PKT_SIZE;
  		size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  		if ((cur_out += size) >= rp->b_size)
  			cur_out -= rp->b_size;
  		bytes += size;
  	}
  
  	mutex_unlock(&rp->fetch_lock);
  	return nevents;
  }
  
  /*
   * Count events. This is almost the same as the above mon_bin_fetch,
   * only we do not store offsets into user vector, and we have no limit.
   */
  static int mon_bin_queued(struct mon_reader_bin *rp)
  {
  	unsigned int cur_out;
  	unsigned int bytes, avail;
  	unsigned int size;
  	unsigned int nevents;
  	struct mon_bin_hdr *ep;
  	unsigned long flags;
  
  	mutex_lock(&rp->fetch_lock);
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  	avail = rp->b_cnt;
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  
  	cur_out = rp->b_out;
  	nevents = 0;
  	bytes = 0;
  	while (bytes < avail) {
  		ep = MON_OFF2HDR(rp, cur_out);
  
  		nevents++;
  		size = ep->len_cap + PKT_SIZE;
  		size = (size + PKT_ALIGN-1) & ~(PKT_ALIGN-1);
  		if ((cur_out += size) >= rp->b_size)
  			cur_out -= rp->b_size;
  		bytes += size;
  	}
  
  	mutex_unlock(&rp->fetch_lock);
  	return nevents;
  }
  
  /*
   */
  static long mon_bin_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  {
  	struct mon_reader_bin *rp = file->private_data;
  	// struct mon_bus* mbus = rp->r.m_bus;
  	int ret = 0;
  	struct mon_bin_hdr *ep;
  	unsigned long flags;
  
  	switch (cmd) {
  
  	case MON_IOCQ_URB_LEN:
  		/*
  		 * N.B. This only returns the size of data, without the header.
  		 */
  		spin_lock_irqsave(&rp->b_lock, flags);
  		if (!MON_RING_EMPTY(rp)) {
  			ep = MON_OFF2HDR(rp, rp->b_out);
  			ret = ep->len_cap;
  		}
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		break;
  
  	case MON_IOCQ_RING_SIZE:
  		ret = rp->b_size;
  		break;
  
  	case MON_IOCT_RING_SIZE:
  		/*
  		 * Changing the buffer size will flush it's contents; the new
  		 * buffer is allocated before releasing the old one to be sure
  		 * the device will stay functional also in case of memory
  		 * pressure.
  		 */
  		{
  		int size;
  		struct mon_pgmap *vec;
  
  		if (arg < BUFF_MIN || arg > BUFF_MAX)
  			return -EINVAL;
  
  		size = CHUNK_ALIGN(arg);
  		if ((vec = kzalloc(sizeof(struct mon_pgmap) * (size/CHUNK_SIZE),
  		    GFP_KERNEL)) == NULL) {
  			ret = -ENOMEM;
  			break;
  		}
  
  		ret = mon_alloc_buff(vec, size/CHUNK_SIZE);
  		if (ret < 0) {
  			kfree(vec);
  			break;
  		}
  
  		mutex_lock(&rp->fetch_lock);
  		spin_lock_irqsave(&rp->b_lock, flags);
  		mon_free_buff(rp->b_vec, rp->b_size/CHUNK_SIZE);
  		kfree(rp->b_vec);
  		rp->b_vec  = vec;
  		rp->b_size = size;
  		rp->b_read = rp->b_in = rp->b_out = rp->b_cnt = 0;
  		rp->cnt_lost = 0;
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		mutex_unlock(&rp->fetch_lock);
  		}
  		break;
  
  	case MON_IOCH_MFLUSH:
  		ret = mon_bin_flush(rp, arg);
  		break;
  
  	case MON_IOCX_GET:
  	case MON_IOCX_GETX:
  		{
  		struct mon_bin_get getb;
  
  		if (copy_from_user(&getb, (void __user *)arg,
  					    sizeof(struct mon_bin_get)))
  			return -EFAULT;
  
  		if (getb.alloc > 0x10000000)	/* Want to cast to u32 */
  			return -EINVAL;
  		ret = mon_bin_get_event(file, rp, getb.hdr,
  		    (cmd == MON_IOCX_GET)? PKT_SZ_API0: PKT_SZ_API1,
  		    getb.data, (unsigned int)getb.alloc);
  		}
  		break;
  
  	case MON_IOCX_MFETCH:
  		{
  		struct mon_bin_mfetch mfetch;
  		struct mon_bin_mfetch __user *uptr;
  
  		uptr = (struct mon_bin_mfetch __user *)arg;
  
  		if (copy_from_user(&mfetch, uptr, sizeof(mfetch)))
  			return -EFAULT;
  
  		if (mfetch.nflush) {
  			ret = mon_bin_flush(rp, mfetch.nflush);
  			if (ret < 0)
  				return ret;
  			if (put_user(ret, &uptr->nflush))
  				return -EFAULT;
  		}
  		ret = mon_bin_fetch(file, rp, mfetch.offvec, mfetch.nfetch);
  		if (ret < 0)
  			return ret;
  		if (put_user(ret, &uptr->nfetch))
  			return -EFAULT;
  		ret = 0;
  		}
  		break;
  
  	case MON_IOCG_STATS: {
  		struct mon_bin_stats __user *sp;
  		unsigned int nevents;
  		unsigned int ndropped;
  
  		spin_lock_irqsave(&rp->b_lock, flags);
  		ndropped = rp->cnt_lost;
  		rp->cnt_lost = 0;
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  		nevents = mon_bin_queued(rp);
  
  		sp = (struct mon_bin_stats __user *)arg;
  		if (put_user(rp->cnt_lost, &sp->dropped))
  			return -EFAULT;
  		if (put_user(nevents, &sp->queued))
  			return -EFAULT;
  
  		}
  		break;
  
  	default:
  		return -ENOTTY;
  	}
  
  	return ret;
  }
  
  #ifdef CONFIG_COMPAT
  static long mon_bin_compat_ioctl(struct file *file,
      unsigned int cmd, unsigned long arg)
  {
  	struct mon_reader_bin *rp = file->private_data;
  	int ret;
  
  	switch (cmd) {
  
  	case MON_IOCX_GET32:
  	case MON_IOCX_GETX32:
  		{
  		struct mon_bin_get32 getb;
  
  		if (copy_from_user(&getb, (void __user *)arg,
  					    sizeof(struct mon_bin_get32)))
  			return -EFAULT;
  
  		ret = mon_bin_get_event(file, rp, compat_ptr(getb.hdr32),
  		    (cmd == MON_IOCX_GET32)? PKT_SZ_API0: PKT_SZ_API1,
  		    compat_ptr(getb.data32), getb.alloc32);
  		if (ret < 0)
  			return ret;
  		}
  		return 0;
  
  	case MON_IOCX_MFETCH32:
  		{
  		struct mon_bin_mfetch32 mfetch;
  		struct mon_bin_mfetch32 __user *uptr;
  
  		uptr = (struct mon_bin_mfetch32 __user *) compat_ptr(arg);
  
  		if (copy_from_user(&mfetch, uptr, sizeof(mfetch)))
  			return -EFAULT;
  
  		if (mfetch.nflush32) {
  			ret = mon_bin_flush(rp, mfetch.nflush32);
  			if (ret < 0)
  				return ret;
  			if (put_user(ret, &uptr->nflush32))
  				return -EFAULT;
  		}
  		ret = mon_bin_fetch(file, rp, compat_ptr(mfetch.offvec32),
  		    mfetch.nfetch32);
  		if (ret < 0)
  			return ret;
  		if (put_user(ret, &uptr->nfetch32))
  			return -EFAULT;
  		}
  		return 0;
  
  	case MON_IOCG_STATS:
  		return mon_bin_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
  
  	case MON_IOCQ_URB_LEN:
  	case MON_IOCQ_RING_SIZE:
  	case MON_IOCT_RING_SIZE:
  	case MON_IOCH_MFLUSH:
  		return mon_bin_ioctl(file, cmd, arg);
  
  	default:
  		;
  	}
  	return -ENOTTY;
  }
  #endif /* CONFIG_COMPAT */
  
  static unsigned int
  mon_bin_poll(struct file *file, struct poll_table_struct *wait)
  {
  	struct mon_reader_bin *rp = file->private_data;
  	unsigned int mask = 0;
  	unsigned long flags;
  
  	if (file->f_mode & FMODE_READ)
  		poll_wait(file, &rp->b_wait, wait);
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  	if (!MON_RING_EMPTY(rp))
  		mask |= POLLIN | POLLRDNORM;    /* readable */
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  	return mask;
  }
  
  /*
   * open and close: just keep track of how many times the device is
   * mapped, to use the proper memory allocation function.
   */
  static void mon_bin_vma_open(struct vm_area_struct *vma)
  {
  	struct mon_reader_bin *rp = vma->vm_private_data;
  	rp->mmap_active++;
  }
  
  static void mon_bin_vma_close(struct vm_area_struct *vma)
  {
  	struct mon_reader_bin *rp = vma->vm_private_data;
  	rp->mmap_active--;
  }
  
  /*
   * Map ring pages to user space.
   */
  static int mon_bin_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
  {
  	struct mon_reader_bin *rp = vma->vm_private_data;
  	unsigned long offset, chunk_idx;
  	struct page *pageptr;
  
  	offset = vmf->pgoff << PAGE_SHIFT;
  	if (offset >= rp->b_size)
  		return VM_FAULT_SIGBUS;
  	chunk_idx = offset / CHUNK_SIZE;
  	pageptr = rp->b_vec[chunk_idx].pg;
  	get_page(pageptr);
  	vmf->page = pageptr;
  	return 0;
  }
  
  static const struct vm_operations_struct mon_bin_vm_ops = {
  	.open =     mon_bin_vma_open,
  	.close =    mon_bin_vma_close,
  	.fault =    mon_bin_vma_fault,
  };
  
  static int mon_bin_mmap(struct file *filp, struct vm_area_struct *vma)
  {
  	/* don't do anything here: "fault" will set up page table entries */
  	vma->vm_ops = &mon_bin_vm_ops;
  	vma->vm_flags |= VM_RESERVED;
  	vma->vm_private_data = filp->private_data;
  	mon_bin_vma_open(vma);
  	return 0;
  }
  
  static const struct file_operations mon_fops_binary = {
  	.owner =	THIS_MODULE,
  	.open =		mon_bin_open,
  	.llseek =	no_llseek,
  	.read =		mon_bin_read,
  	/* .write =	mon_text_write, */
  	.poll =		mon_bin_poll,
  	.unlocked_ioctl = mon_bin_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl =	mon_bin_compat_ioctl,
  #endif
  	.release =	mon_bin_release,
  	.mmap =		mon_bin_mmap,
  };
  
  static int mon_bin_wait_event(struct file *file, struct mon_reader_bin *rp)
  {
  	DECLARE_WAITQUEUE(waita, current);
  	unsigned long flags;
  
  	add_wait_queue(&rp->b_wait, &waita);
  	set_current_state(TASK_INTERRUPTIBLE);
  
  	spin_lock_irqsave(&rp->b_lock, flags);
  	while (MON_RING_EMPTY(rp)) {
  		spin_unlock_irqrestore(&rp->b_lock, flags);
  
  		if (file->f_flags & O_NONBLOCK) {
  			set_current_state(TASK_RUNNING);
  			remove_wait_queue(&rp->b_wait, &waita);
  			return -EWOULDBLOCK; /* Same as EAGAIN in Linux */
  		}
  		schedule();
  		if (signal_pending(current)) {
  			remove_wait_queue(&rp->b_wait, &waita);
  			return -EINTR;
  		}
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		spin_lock_irqsave(&rp->b_lock, flags);
  	}
  	spin_unlock_irqrestore(&rp->b_lock, flags);
  
  	set_current_state(TASK_RUNNING);
  	remove_wait_queue(&rp->b_wait, &waita);
  	return 0;
  }
  
  static int mon_alloc_buff(struct mon_pgmap *map, int npages)
  {
  	int n;
  	unsigned long vaddr;
  
  	for (n = 0; n < npages; n++) {
  		vaddr = get_zeroed_page(GFP_KERNEL);
  		if (vaddr == 0) {
  			while (n-- != 0)
  				free_page((unsigned long) map[n].ptr);
  			return -ENOMEM;
  		}
  		map[n].ptr = (unsigned char *) vaddr;
  		map[n].pg = virt_to_page((void *) vaddr);
  	}
  	return 0;
  }
  
  static void mon_free_buff(struct mon_pgmap *map, int npages)
  {
  	int n;
  
  	for (n = 0; n < npages; n++)
  		free_page((unsigned long) map[n].ptr);
  }
  
  int mon_bin_add(struct mon_bus *mbus, const struct usb_bus *ubus)
  {
  	struct device *dev;
  	unsigned minor = ubus? ubus->busnum: 0;
  
  	if (minor >= MON_BIN_MAX_MINOR)
  		return 0;
  
  	dev = device_create(mon_bin_class, ubus ? ubus->controller : NULL,
  			    MKDEV(MAJOR(mon_bin_dev0), minor), NULL,
  			    "usbmon%d", minor);
  	if (IS_ERR(dev))
  		return 0;
  
  	mbus->classdev = dev;
  	return 1;
  }
  
  void mon_bin_del(struct mon_bus *mbus)
  {
  	device_destroy(mon_bin_class, mbus->classdev->devt);
  }
  
  int __init mon_bin_init(void)
  {
  	int rc;
  
  	mon_bin_class = class_create(THIS_MODULE, "usbmon");
  	if (IS_ERR(mon_bin_class)) {
  		rc = PTR_ERR(mon_bin_class);
  		goto err_class;
  	}
  
  	rc = alloc_chrdev_region(&mon_bin_dev0, 0, MON_BIN_MAX_MINOR, "usbmon");
  	if (rc < 0)
  		goto err_dev;
  
  	cdev_init(&mon_bin_cdev, &mon_fops_binary);
  	mon_bin_cdev.owner = THIS_MODULE;
  
  	rc = cdev_add(&mon_bin_cdev, mon_bin_dev0, MON_BIN_MAX_MINOR);
  	if (rc < 0)
  		goto err_add;
  
  	return 0;
  
  err_add:
  	unregister_chrdev_region(mon_bin_dev0, MON_BIN_MAX_MINOR);
  err_dev:
  	class_destroy(mon_bin_class);
  err_class:
  	return rc;
  }
  
  void mon_bin_exit(void)
  {
  	cdev_del(&mon_bin_cdev);
  	unregister_chrdev_region(mon_bin_dev0, MON_BIN_MAX_MINOR);
  	class_destroy(mon_bin_class);
  }
  