From: James Cammarata <jimi@sngx.net>
Added the ability to write to /proc/net/dev in order to clear the
interface counters for a given interface. The ability to zero out
counters (especially the error counters) is extremely useful when
troubleshooting interface issues.
Syntax:
echo 'net clear-stats ifdev' > /proc/net/dev
Where "ifdev" is the device name you wish to clear.
This code is based mainly on the code found in drivers/scsi/scsi_proc.c
Signed-off-by: James Cammarata <jimi@sngx.net>
---
--- net/core/dev.original 2008-05-13 12:48:46.000000000 -0400
+++ net/core/dev.c 2008-05-13 13:17:15.000000000 -0400
@@ -2453,6 +2453,87 @@ static struct netif_rx_stats *softnet_ge
return rc;
}
+/**
+ * proc_net_dev_write - handle writes to /proc/net/dev
+ * @file: not used
+ * @buf: buffer to write
+ * @length: length of buf, at most PAGE_SIZE
+ * @ppos: not used
+ *
+ * Description: this provides a mechanism to clear statistics on a
+ * per-interface basis
+ * "echo 'net clear-stats ifdev' >/proc/net/dev"
+ * with "ifdev" replaced by the device name you wish to clear.
+ *
+ */
+static ssize_t proc_net_dev_write(struct file *file, const char __user
*buf,
+ size_t length, loff_t *ppos)
+{
+ char *buffer, *p;
+ char devname[IFNAMSIZ];
+ struct net *net;
+ struct net_device *dev;
+ int err;
+
+ if (!buf || length > PAGE_SIZE)
+ return -EINVAL;
+
+ buffer = (char *)__get_free_page(GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ err = -EFAULT;
+ if (copy_from_user(buffer, buf, length))
+ goto out;
+
+ err = -EINVAL;
+ if (length < PAGE_SIZE)
+ buffer[length] = '\0';
+ else if (buffer[PAGE_SIZE-1])
+ goto out;
+
+ err = -ENXIO;
+ net = get_proc_net(file->f_dentry->d_inode);
+ if (!net)
+ goto out;
+
+ /*
+ * Usage: echo "net clear-stats ifdev" >/proc/net/dev
+ * with "ifdev" replaced by the device name you wish to clear.
+ */
+ if (!strncmp("net clear-stats",buffer,15)) {
+ p = buffer + 16;
+ sscanf(p,"%s",devname);
+ printk(KERN_INFO "net clearing stats - device is:
%s\n", devname);
+ dev = dev_get_by_name(net,devname);
+ if (!dev) {
+ printk(KERN_INFO "no interface named '%s'\n",
devname);
+ } else {
+ if (dev->get_stats) {
+ struct net_device_stats *stats =
dev->get_stats(dev);
+ memset(stats,0,sizeof(struct
net_device_stats));
+ printk(KERN_INFO "stats cleared for
interface %s\n", devname);
+ } else {
+ printk(KERN_INFO "%s has no stats to
clear\n", devname);
+ }
+ dev_put(dev);
+ }
+ }
+
+ /*
+ * convert success returns so that we return the
+ * number of bytes consumed.
+ */
+ if (!err)
+ err = length;
+
+ out:
+ free_page((unsigned long)buffer);
+ return err;
+}
+
static void *softnet_seq_start(struct seq_file *seq, loff_t *pos)
{
return softnet_get_online(pos);
@@ -2496,6 +2577,7 @@ static const struct file_operations dev_
.owner = THIS_MODULE,
.open = dev_seq_open,
.read = seq_read,
+ .write = proc_net_dev_write,
.llseek = seq_lseek,
.release = seq_release_net,
};
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