[PATCH 1/4] [net-2.6.22] IrDA: IrLAP raw mode

[PATCH 1/4] [net-2.6.22] IrDA: IrLAP raw mode

[Samuel Ortiz]

This patch allows us to bypass the IrDA stack down to the IrLAP level.
Sending and receiving frames is done through a character device.
This is useful for e.g. doing real IrDA sniffing, testing external IrDA
stacks and for Lirc (once I will add the framing disabling switch).

Signed-off-by: Samuel Ortiz <samuel-jcdQHdrhKHMdnm+yROfE0A@public.gmane.org>
---
 include/net/irda/irlap.h     |    5 +
 include/net/irda/irlap_raw.h |   57 +++++++
 net/irda/Kconfig             |   10 ++
 net/irda/Makefile            |    1 +
 net/irda/irlap.c             |    5 +
 net/irda/irlap_event.c       |    3 +
 net/irda/irlap_frame.c       |    4 +
 net/irda/irlap_raw.c         |  358 ++++++++++++++++++++++++++++++++++++++++++
 net/irda/irsysctl.c          |   16 ++-
 9 files changed, 458 insertions(+), 1 deletions(-)
 create mode 100644 include/net/irda/irlap_raw.h
 create mode 100644 net/irda/irlap_raw.c

diff --git a/include/net/irda/irlap.h b/include/net/irda/irlap.h
index e77eb88..1b24cfc 100644
--- a/include/net/irda/irlap.h
+++ b/include/net/irda/irlap.h
@@ -36,6 +36,7 @@
 #include <net/irda/qos.h>		/* struct qos_info */
 #include <net/irda/discovery.h>		/* discovery_t */
 #include <net/irda/irlap_event.h>	/* IRLAP_STATE, ... */
+#include <net/irda/irlap_raw.h>	        /* IRLAP raw definitions */
 #include <net/irda/irmod.h>		/* struct notify_t */
 
 #define CONFIG_IRDA_DYNAMIC_WINDOW 1
@@ -208,6 +209,10 @@ struct irlap_cb {
 	int    xbofs_delay;   /* Nr of XBOF's used to MTT */
 	int    bofs_count;    /* Negotiated extra BOFs */
 	int    next_bofs;     /* Negotiated extra BOFs after next frame */
+#ifdef CONFIG_IRDA_RAW
+	int    raw_mode;
+	struct irlap_raw * irlap_raw;
+#endif
 };
 
 /* 
diff --git a/include/net/irda/irlap_raw.h b/include/net/irda/irlap_raw.h
new file mode 100644
index 0000000..ce90563
--- /dev/null
+++ b/include/net/irda/irlap_raw.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2007 Samuel Ortiz (samuel-jcdQHdrhKHMdnm+yROfE0A@public.gmane.org)
+ *
+ * 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, version 2.
+ *
+ */
+
+#ifndef _IRLAP_RAW_H
+#define _IRLAP_RAW_H
+
+struct irlap_cb;
+
+#ifdef CONFIG_IRDA_RAW
+
+extern int irlap_raw_recv_frame(struct sk_buff *skb, struct net_device *dev);
+extern int irlap_raw_register_device(struct net_device * dev);
+extern int irlap_raw_unregister_device(struct net_device * dev);
+extern int irlap_raw_mode(struct irlap_cb *self);
+
+#else
+
+static inline int irlap_raw_recv_frame(struct sk_buff *skb,
+				       struct net_device *dev)
+{
+        if (skb == NULL)
+                return -EINVAL;
+
+        if (dev->atalk_ptr == NULL)
+                return -ENODEV;
+
+        return 0;
+}
+
+static inline int irlap_raw_register_device(struct net_device * dev)
+{
+        if (dev == NULL)
+                return -ENODEV;
+        return 0;
+}
+
+static inline int irlap_raw_unregister_device(struct net_device * dev)
+{
+        if (dev == NULL)
+                return -ENODEV;
+        return 0;
+}
+
+static inline int irlap_raw_mode(struct irlap_cb *self)
+{
+        return 0;
+}
+
+#endif
+
+#endif
diff --git a/net/irda/Kconfig b/net/irda/Kconfig
index 9efb17b..310a036 100644
--- a/net/irda/Kconfig
+++ b/net/irda/Kconfig
@@ -92,5 +92,15 @@ config IRDA_DEBUG
 
 	  If unsure, say Y (since it makes it easier to find the bugs).
 
+config IRDA_RAW
+	bool "IrLAP raw"
+	depends on IRDA
+	help
+	  Say Y if you want to bypass the IrDA stack, down to the IrLAP level.
+	  This option allows you to send and receive IrLAP frames from
+	  userspace, by writing and reading to a character device
+	  (/dev/irdaX_raw). Note that the IrDA stack will be mostly disabled.
+	  If unsure, say N.
+
 source "drivers/net/irda/Kconfig"
 
diff --git a/net/irda/Makefile b/net/irda/Makefile
index d1366c2..11d5ffb 100644
--- a/net/irda/Makefile
+++ b/net/irda/Makefile
@@ -13,3 +13,4 @@ irda-y := iriap.o iriap_event.o irlmp.o irlmp_event.o irlmp_frame.o \
 	  discovery.o parameters.o irmod.o
 irda-$(CONFIG_PROC_FS) += irproc.o
 irda-$(CONFIG_SYSCTL) += irsysctl.o
+irda-$(CONFIG_IRDA_RAW) += irlap_raw.o
diff --git a/net/irda/irlap.c b/net/irda/irlap.c
index d93ebd1..656c949 100644
--- a/net/irda/irlap.c
+++ b/net/irda/irlap.c
@@ -173,6 +173,8 @@ struct irlap_cb *irlap_open(struct net_device *dev, struct qos_info *qos,
 
 	irlmp_register_link(self, self->saddr, &self->notify);
 
+	irlap_raw_register_device(dev);
+
 	return self;
 }
 EXPORT_SYMBOL(irlap_open);
@@ -234,6 +236,9 @@ void irlap_close(struct irlap_cb *self)
 		IRDA_DEBUG(1, "%s(), Didn't find myself!\n", __FUNCTION__);
 		return;
 	}
+
+	irlap_raw_unregister_device(self->netdev);
+
 	__irlap_close(lap);
 }
 EXPORT_SYMBOL(irlap_close);
diff --git a/net/irda/irlap_event.c b/net/irda/irlap_event.c
index 7b6433f..3a11c3e 100644
--- a/net/irda/irlap_event.c
+++ b/net/irda/irlap_event.c
@@ -241,6 +241,9 @@ void irlap_do_event(struct irlap_cb *self, IRLAP_EVENT event,
 	if (!self || self->magic != LAP_MAGIC)
 		return;
 
+	if (irlap_raw_mode(self))
+		return;
+
 	IRDA_DEBUG(3, "%s(), event = %s, state = %s\n", __FUNCTION__,
 		   irlap_event[event], irlap_state[self->state]);
 
diff --git a/net/irda/irlap_frame.c b/net/irda/irlap_frame.c
index 803ac41..5a3a868 100644
--- a/net/irda/irlap_frame.c
+++ b/net/irda/irlap_frame.c
@@ -1325,6 +1325,10 @@ int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,
 		return -1;
 	}
 
+       if (irlap_raw_mode(self)) {
+               return irlap_raw_recv_frame(skb, dev);
+       }
+
 	/* We are no longer an "old" protocol, so we need to handle
 	 * share and non linear skbs. This should never happen, so
 	 * we don't need to be clever about it. Jean II */
diff --git a/net/irda/irlap_raw.c b/net/irda/irlap_raw.c
new file mode 100644
index 0000000..705424e
--- /dev/null
+++ b/net/irda/irlap_raw.c
@@ -0,0 +1,358 @@
+/*
+ * net/irda/irlap_raw.c Raw IrLAP character device.
+ * Copyright (C) 2007 Samuel Ortiz (samuel-jcdQHdrhKHMdnm+yROfE0A@public.gmane.org)
+ *
+ * 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, version 2.
+ *
+ * From /dev/irdaN_raw, you can read and write raw IrLAP frames.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+#include <linux/miscdevice.h>
+#include <linux/wait.h>
+
+#include <net/irda/irda.h>
+#include <net/irda/irda_device.h>
+#include <net/irda/irlap.h>
+#include <net/irda/irlap_raw.h>
+
+/* We keep the last 10 IrLAP frames */
+unsigned int sysctl_raw_ring_length = 10;
+
+struct irlap_raw {
+	struct list_head    list;
+	char                name[IFNAMSIZ + 8];
+	struct miscdevice   misc_device;
+	struct irlap_cb     * irlap;
+	struct sk_buff_head skb_ring;
+	wait_queue_head_t   rx_wait;
+	unsigned int        refcount;
+	struct mutex        rx_mutex;
+	struct mutex        tx_mutex;
+	struct work_struct  skb_ring_work;
+};
+
+static LIST_HEAD(irlap_raw_list);
+static DEFINE_MUTEX(irlap_raw_mutex);
+
+static void irlap_raw_skb_ring_gc(struct work_struct *work)
+{
+	struct irlap_raw * raw =
+		container_of(work, struct irlap_raw, skb_ring_work);
+
+	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
+
+	if (mutex_lock_interruptible(&raw->rx_mutex))
+		return;
+
+	while(skb_queue_len(&raw->skb_ring) > sysctl_raw_ring_length) {
+		struct sk_buff * old_skb;
+
+		IRDA_DEBUG(3, "%s(): We still have %d entries\n",
+			   __FUNCTION__, skb_queue_len(&raw->skb_ring));
+
+		old_skb = skb_dequeue_tail(&raw->skb_ring);
+		dev_kfree_skb(old_skb);
+	}
+
+	mutex_unlock(&raw->rx_mutex);
+}
+
+int irlap_raw_recv_frame(struct sk_buff *skb, struct net_device *dev)
+{
+	struct irlap_cb * irlap;
+	struct irlap_raw * raw;
+
+	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
+
+	irlap = dev->atalk_ptr;
+	if (irlap == NULL)
+		return -ENODEV;
+
+	if (skb == NULL)
+		return -EINVAL;
+
+	raw = irlap->irlap_raw;
+	if (raw == NULL)
+		return -ENODEV;
+
+	skb_queue_head(&raw->skb_ring, skb);
+
+	wake_up_interruptible(&raw->rx_wait);
+
+	/*
+	 * We call the "garbage collector" in process
+	 * context, so that we can lock the skb removal
+	 * against read().
+	 */
+	if (skb_queue_len(&raw->skb_ring) > sysctl_raw_ring_length) {
+		IRDA_DEBUG(3, "%s(): We have %d entries, time to clean up\n",
+			   __FUNCTION__, skb_queue_len(&raw->skb_ring));
+		schedule_work(&raw->skb_ring_work);
+	}
+
+	return 0;
+}
+
+ssize_t irlap_raw_read(struct file * file, char __user * buf,
+		       size_t count, loff_t * ppos)
+{
+	int ret = 0;
+	struct irlap_raw * raw;
+	struct sk_buff * frame;
+
+	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
+
+	raw = file->private_data;
+
+	ret = mutex_lock_interruptible(&raw->rx_mutex);
+	if (ret)
+		return ret;
+
+	ret = wait_event_interruptible(raw->rx_wait,
+				       !skb_queue_empty(&raw->skb_ring));
+	if (ret < 0)
+		goto out;
+
+	if (skb_queue_empty(&raw->skb_ring)) {
+		ret = -EINTR;
+		IRDA_DEBUG(3, "%s(): Queue is empty\n", __FUNCTION__);
+		goto out;
+	}
+
+	frame = skb_dequeue_tail(&raw->skb_ring);
+
+	if (frame == NULL) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (copy_to_user(buf, frame->data, frame->len)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = frame->len;
+	dev_kfree_skb(frame);
+
+ out:
+	mutex_unlock(&raw->rx_mutex);
+
+	IRDA_DEBUG(3, "%s(): Read %d bytes\n", __FUNCTION__, ret);
+	return ret;
+}
+
+extern void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb);
+ssize_t irlap_raw_write(struct file * file, const char __user * buf,
+			size_t count, loff_t * ppos)
+{
+	int ret;
+	struct irlap_raw * raw;
+	struct sk_buff *tx_skb;
+
+	IRDA_DEBUG(3, "%s(): Trying to write %d bytes\n", __FUNCTION__, count);
+
+	raw = file->private_data;
+
+	ret = mutex_lock_interruptible(&raw->tx_mutex);
+	if (ret)
+		return ret;
+
+	if (count == 0)
+		goto out;
+
+	tx_skb = alloc_skb(IRDA_SIR_MAX_FRAME, GFP_KERNEL);
+	if (tx_skb == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (copy_from_user(skb_put(tx_skb, count), buf, count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	irlap_queue_xmit(raw->irlap, tx_skb);
+
+	ret = count;
+ out:
+	mutex_unlock(&raw->tx_mutex);
+
+	IRDA_DEBUG(3, "%s(): Wrote %d bytes\n", __FUNCTION__, ret);
+	return ret;
+}
+
+unsigned int irlap_raw_poll(struct file * file,
+			    struct poll_table_struct * table)
+{
+	int ret = 0;
+	struct irlap_raw * raw;
+
+	raw = file->private_data;
+
+        poll_wait(file, &raw->rx_wait, table);
+
+        if (!skb_queue_empty(&raw->skb_ring))
+                ret = POLLIN | POLLRDNORM;
+	else
+		ret = POLLOUT | POLLWRNORM;
+
+	return ret;
+}
+
+int irlap_raw_open(struct inode * inode, struct file * file)
+{
+	unsigned int minor = iminor(inode);
+	int ret = -ENODEV;
+	struct irlap_raw * raw, * tmp;
+
+	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);
+
+	mutex_lock_interruptible(&irlap_raw_mutex);
+	list_for_each_entry_safe(raw, tmp, &irlap_raw_list, list) {
+		if (raw->misc_device.minor == minor) {
+			IRDA_DEBUG(3, "%s(): Found raw (minor: %d)\n",
+				   __FUNCTION__, minor);
+			file->private_data = raw;
+			raw->irlap->raw_mode = 1;
+			raw->refcount++;
+			mutex_unlock(&irlap_raw_mutex);
+			return 0;
+		}
+	}
+
+	mutex_unlock(&irlap_raw_mutex);
+	return ret;
+}
+
+int irlap_raw_release(struct inode * inode, struct file * file)
+{
+	struct irlap_raw * raw;
+
+	if (file->private_data) {
+		mutex_lock_interruptible(&irlap_raw_mutex);
+
+		raw = file->private_data;
+		if (raw->refcount > 0)
+			raw->refcount--;
+
+		if (raw->refcount == 0) {
+			skb_queue_purge(&raw->skb_ring);
+			raw->irlap->raw_mode = 0;
+		}
+
+		file->private_data = NULL;
+
+		mutex_unlock(&irlap_raw_mutex);
+	}
+
+	return 0;
+}
+
+static const struct file_operations irlap_raw_fops = {
+	.owner		= THIS_MODULE,
+	.read		= irlap_raw_read,
+	.write          = irlap_raw_write,
+	.poll		= irlap_raw_poll,
+	.open		= irlap_raw_open,
+	.release	= irlap_raw_release,
+};
+
+
+int irlap_raw_register_device(struct net_device * dev)
+{
+	int ret = 0;
+	struct irlap_cb * irlap;
+	struct irlap_raw * raw;
+
+	if (dev == NULL)
+		return -ENODEV;
+
+	raw = kzalloc(sizeof(struct irlap_raw), GFP_KERNEL);
+	if (raw == NULL)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&raw->list);
+	INIT_WORK(&raw->skb_ring_work, irlap_raw_skb_ring_gc);
+	mutex_init(&raw->rx_mutex);
+	mutex_init(&raw->tx_mutex);
+	raw->refcount = 0;
+	skb_queue_head_init(&raw->skb_ring);
+
+	sprintf(raw->name, "%s_raw", dev->name);
+	raw->misc_device.minor = MISC_DYNAMIC_MINOR;
+	raw->misc_device.name = raw->name;
+	raw->misc_device.fops = &irlap_raw_fops;
+
+	list_add(&raw->list, &irlap_raw_list);
+
+	irlap = dev->atalk_ptr;
+	if (irlap == NULL) {
+		ret = -ENODEV;
+		goto out_err;
+	}
+
+        /* We'll enter raw mode whenever the device is open */
+	irlap->raw_mode = 0;
+	irlap->irlap_raw = raw;
+
+	init_waitqueue_head(&raw->rx_wait);
+
+	raw->irlap = irlap;
+
+	ret = misc_register(&raw->misc_device);
+	if (!ret) {
+		printk(KERN_INFO "Registered %s raw IrLAP device\n", raw->name);
+		return ret;
+	}
+
+ out_err:
+	irlap->irlap_raw = NULL;
+	kfree(raw);
+	return ret;
+
+}
+
+int irlap_raw_unregister_device(struct net_device * dev)
+{
+	struct irlap_cb * irlap;
+	struct irlap_raw * raw;
+
+	irlap = dev->atalk_ptr;
+	if (irlap == NULL)
+		return -ENODEV;
+
+	raw = irlap->irlap_raw;
+	mutex_lock_interruptible(&irlap_raw_mutex);
+	if (raw->refcount) {
+		mutex_unlock(&irlap_raw_mutex);
+		return -EBUSY;
+	}
+
+	printk(KERN_INFO "%s unregistered\n", raw->name);
+
+	list_del(&raw->list);
+	misc_deregister(&raw->misc_device);
+
+	mutex_unlock(&irlap_raw_mutex);
+
+	kfree(raw);
+
+	return 0;
+}
+
+inline int irlap_raw_mode(struct irlap_cb *self)
+{
+        return self->raw_mode;
+}
diff --git a/net/irda/irsysctl.c b/net/irda/irsysctl.c
index 2e968e7..a7e967d 100644
--- a/net/irda/irsysctl.c
+++ b/net/irda/irsysctl.c
@@ -35,7 +35,7 @@
 enum { DISCOVERY=1, DEVNAME, DEBUG, FAST_POLL, DISCOVERY_SLOTS,
        DISCOVERY_TIMEOUT, SLOT_TIMEOUT, MAX_BAUD_RATE, MIN_TX_TURN_TIME,
        MAX_TX_DATA_SIZE, MAX_TX_WINDOW, MAX_NOREPLY_TIME, WARN_NOREPLY_TIME,
-       LAP_KEEPALIVE_TIME };
+       LAP_KEEPALIVE_TIME, RAW_RING_LENGTH };
 
 extern int  sysctl_discovery;
 extern int  sysctl_discovery_slots;
@@ -50,6 +50,9 @@ extern int  sysctl_max_tx_window;
 extern int  sysctl_max_noreply_time;
 extern int  sysctl_warn_noreply_time;
 extern int  sysctl_lap_keepalive_time;
+#ifdef CONFIG_IRDA_RAW
+extern unsigned int  sysctl_raw_ring_length;
+#endif
 
 /* this is needed for the proc_dointvec_minmax - Jean II */
 static int max_discovery_slots = 16;		/* ??? */
@@ -237,6 +240,17 @@ static ctl_table irda_table[] = {
 		.extra1		= &min_lap_keepalive_time,
 		.extra2		= &max_lap_keepalive_time
 	},
+#ifdef CONFIG_IRDA_RAW
+	{
+		.ctl_name	= RAW_RING_LENGTH,
+		.procname	= "raw_ring_length",
+		.data		= &sysctl_raw_ring_length,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
+#endif
+
 	{ .ctl_name = 0 }
 };
 
-- 
1.5.0.2


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV

Re: [PATCH 1/4] [net-2.6.22] IrDA: IrLAP raw mode

[David Miller]

From: Samuel Ortiz <samuel@sortiz.org>
Date: Sat, 17 Mar 2007 03:57:29 +0200

> This patch allows us to bypass the IrDA stack down to the IrLAP level.
> Sending and receiving frames is done through a character device.
> This is useful for e.g. doing real IrDA sniffing, testing external IrDA
> stacks and for Lirc (once I will add the framing disabling switch).
> 
> Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

I understand the idea, but I fail to see any reason this should not be
done with sockets.

Everywhere else we provide this kind of functionality it is either
with netlink (nf_queue etc.) or raw sockets of some kind
(AF_INET/SOCK_RAW, AF_PACKET, etc.)

Therefore IRDA should really provide this facility in some similar
manner.  Besides, character device backdoors for networking are
just ugly :)

Re: [PATCH 1/4] [net-2.6.22] IrDA: IrLAP raw mode

[Samuel Ortiz]

On Fri, Mar 16, 2007 at 08:34:51PM -0700, David Miller wrote:
> From: Samuel Ortiz <samuel-jcdQHdrhKHMdnm+yROfE0A@public.gmane.org>
> Date: Sat, 17 Mar 2007 03:57:29 +0200
> 
> > This patch allows us to bypass the IrDA stack down to the IrLAP level.
> > Sending and receiving frames is done through a character device.
> > This is useful for e.g. doing real IrDA sniffing, testing external IrDA
> > stacks and for Lirc (once I will add the framing disabling switch).
> > 
> > Signed-off-by: Samuel Ortiz <samuel-jcdQHdrhKHMdnm+yROfE0A@public.gmane.org>
> 
> I understand the idea, but I fail to see any reason this should not be
> done with sockets.
> 
> Everywhere else we provide this kind of functionality it is either
> with netlink (nf_queue etc.) or raw sockets of some kind
> (AF_INET/SOCK_RAW, AF_PACKET, etc.)
> 
> Therefore IRDA should really provide this facility in some similar
> manner.
I definitely agree here. Actually, you can already sniff IrDA packets through
an AF_PACKET socket, that's what irdadump does. My patch was useless, forget
about it...

I have a question though: On top of the regular IrDA sniffing done with a
simple AF_PACKET socket, I also would like to be able to disable TX at the
IrLAP level (typically, this would allow an IrDA device to listen to all
the packets from an IrDA link without being noticed by the other devices).

I was thinking of adding a protocol private ioctl (as in SIOCPROTOPRIVATE) to
let userspace toggle an IrLAP flag (one per IrLAP instance) that would
disable a specific IrDA device TX path.
Would that be an acceptable solution, or would you rather see a netlink socket
for that purpose ?

Cheers,
Samuel.


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV