USB: add binary API to usbmon
This patch adds a new, "binary" API in addition to the old, text API usbmon
had before. The new API allows for less CPU use, and it allows to capture
all data from a packet where old API only captured 32 bytes at most. There
are some limitations and conditions to this, e.g. in case someone constructs
a URB with 1GB of data, it's not likely to be captured, because even the
huge buffers of the new reader are finite. Nonetheless, I expect this new
capability to capture all data for all real life scenarios.
The downside is, a special user mode application is required where cat(1)
worked before. I have sample code at http://people.redhat.com/zaitcev/linux/
and Paolo Abeni is working on patching libpcap.
This patch was initially written by Paolo and later I tweaked it, and
we had a little back-and-forth. So this is a jointly authored patch, but
I am submitting this I am responsible for the bugs.
Signed-off-by: Paolo Abeni <paolo.abeni@email.it>
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c
index 394bbf2..c9739e7 100644
--- a/drivers/usb/mon/mon_main.c
+++ b/drivers/usb/mon/mon_main.c
@@ -9,7 +9,6 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
-#include <linux/debugfs.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/mutex.h>
@@ -22,11 +21,10 @@
static void mon_stop(struct mon_bus *mbus);
static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
static void mon_bus_drop(struct kref *r);
-static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus);
+static void mon_bus_init(struct usb_bus *ubus);
DEFINE_MUTEX(mon_lock);
-static struct dentry *mon_dir; /* /dbg/usbmon */
static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
/*
@@ -200,7 +198,7 @@
*/
static void mon_bus_add(struct usb_bus *ubus)
{
- mon_bus_init(mon_dir, ubus);
+ mon_bus_init(ubus);
}
/*
@@ -212,8 +210,8 @@
mutex_lock(&mon_lock);
list_del(&mbus->bus_link);
- debugfs_remove(mbus->dent_t);
- debugfs_remove(mbus->dent_s);
+ if (mbus->text_inited)
+ mon_text_del(mbus);
mon_dissolve(mbus, ubus);
kref_put(&mbus->ref, mon_bus_drop);
@@ -281,13 +279,9 @@
* - refcount USB bus struct
* - link
*/
-static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
+static void mon_bus_init(struct usb_bus *ubus)
{
- struct dentry *d;
struct mon_bus *mbus;
- enum { NAMESZ = 10 };
- char name[NAMESZ];
- int rc;
if ((mbus = kzalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
goto err_alloc;
@@ -303,57 +297,54 @@
ubus->mon_bus = mbus;
mbus->uses_dma = ubus->uses_dma;
- rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
- if (rc <= 0 || rc >= NAMESZ)
- goto err_print_t;
- d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
- if (d == NULL)
- goto err_create_t;
- mbus->dent_t = d;
-
- rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
- if (rc <= 0 || rc >= NAMESZ)
- goto err_print_s;
- d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
- if (d == NULL)
- goto err_create_s;
- mbus->dent_s = d;
+ mbus->text_inited = mon_text_add(mbus, ubus);
+ // mon_bin_add(...)
mutex_lock(&mon_lock);
list_add_tail(&mbus->bus_link, &mon_buses);
mutex_unlock(&mon_lock);
return;
-err_create_s:
-err_print_s:
- debugfs_remove(mbus->dent_t);
-err_create_t:
-err_print_t:
- kfree(mbus);
err_alloc:
return;
}
+/*
+ * Search a USB bus by number. Notice that USB bus numbers start from one,
+ * which we may later use to identify "all" with zero.
+ *
+ * This function must be called with mon_lock held.
+ *
+ * This is obviously inefficient and may be revised in the future.
+ */
+struct mon_bus *mon_bus_lookup(unsigned int num)
+{
+ struct list_head *p;
+ struct mon_bus *mbus;
+
+ list_for_each (p, &mon_buses) {
+ mbus = list_entry(p, struct mon_bus, bus_link);
+ if (mbus->u_bus->busnum == num) {
+ return mbus;
+ }
+ }
+ return NULL;
+}
+
static int __init mon_init(void)
{
struct usb_bus *ubus;
- struct dentry *mondir;
+ int rc;
- mondir = debugfs_create_dir("usbmon", NULL);
- if (IS_ERR(mondir)) {
- printk(KERN_NOTICE TAG ": debugfs is not available\n");
- return -ENODEV;
- }
- if (mondir == NULL) {
- printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
- return -ENODEV;
- }
- mon_dir = mondir;
+ if ((rc = mon_text_init()) != 0)
+ goto err_text;
+ if ((rc = mon_bin_init()) != 0)
+ goto err_bin;
if (usb_mon_register(&mon_ops_0) != 0) {
printk(KERN_NOTICE TAG ": unable to register with the core\n");
- debugfs_remove(mondir);
- return -ENODEV;
+ rc = -ENODEV;
+ goto err_reg;
}
// MOD_INC_USE_COUNT(which_module?);
@@ -361,10 +352,17 @@
mutex_lock(&usb_bus_list_lock);
list_for_each_entry (ubus, &usb_bus_list, bus_list) {
- mon_bus_init(mondir, ubus);
+ mon_bus_init(ubus);
}
mutex_unlock(&usb_bus_list_lock);
return 0;
+
+err_reg:
+ mon_bin_exit();
+err_bin:
+ mon_text_exit();
+err_text:
+ return rc;
}
static void __exit mon_exit(void)
@@ -381,8 +379,8 @@
mbus = list_entry(p, struct mon_bus, bus_link);
list_del(p);
- debugfs_remove(mbus->dent_t);
- debugfs_remove(mbus->dent_s);
+ if (mbus->text_inited)
+ mon_text_del(mbus);
/*
* This never happens, because the open/close paths in
@@ -401,7 +399,8 @@
}
mutex_unlock(&mon_lock);
- debugfs_remove(mon_dir);
+ mon_text_exit();
+ mon_bin_exit();
}
module_init(mon_init);