/*
 * Copyright (c) 2009, 2010 Nicira Networks.
 * Distributed under the terms of the GNU GPL version 2.
 *
 * Significant portions of this file may be copied from parts of the Linux
 * kernel, by Linus Torvalds and others.
 */

/*
 *	Sysfs attributes of bridge ports for Open vSwitch
 *
 *  This has been shamelessly copied from the kernel sources.
 */

#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/if_bridge.h>
#include <linux/rtnetlink.h>

#include "datapath.h"
#include "dp_sysfs.h"
#include "vport.h"

#ifdef CONFIG_SYSFS

struct brport_attribute {
	struct attribute	attr;
	ssize_t (*show)(struct vport *, char *);
	ssize_t (*store)(struct vport *, unsigned long);
};

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
#define BRPORT_ATTR(_name,_mode,_show,_store)		        \
struct brport_attribute brport_attr_##_name = {		        \
	.attr = {.name = __stringify(_name),			\
		 .mode = _mode },				\
	.show	= _show,					\
	.store	= _store,					\
};
#else
#define BRPORT_ATTR(_name,_mode,_show,_store)		        \
struct brport_attribute brport_attr_##_name = { 	        \
	.attr = {.name = __stringify(_name), 			\
		 .mode = _mode, 				\
		 .owner = THIS_MODULE, },			\
	.show	= _show,					\
	.store	= _store,					\
};
#endif

static ssize_t show_path_cost(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static ssize_t store_path_cost(struct vport *p, unsigned long v)
{
	return 0;
}
static BRPORT_ATTR(path_cost, S_IRUGO | S_IWUSR,
		   show_path_cost, store_path_cost);

static ssize_t show_priority(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static ssize_t store_priority(struct vport *p, unsigned long v)
{
	return 0;
}
static BRPORT_ATTR(priority, S_IRUGO | S_IWUSR,
			 show_priority, store_priority);

static ssize_t show_designated_root(struct vport *p, char *buf)
{
	return sprintf(buf, "0000.010203040506\n");
}
static BRPORT_ATTR(designated_root, S_IRUGO, show_designated_root, NULL);

static ssize_t show_designated_bridge(struct vport *p, char *buf)
{
	return sprintf(buf, "0000.060504030201\n");
}
static BRPORT_ATTR(designated_bridge, S_IRUGO, show_designated_bridge, NULL);

static ssize_t show_designated_port(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(designated_port, S_IRUGO, show_designated_port, NULL);

static ssize_t show_designated_cost(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(designated_cost, S_IRUGO, show_designated_cost, NULL);

static ssize_t show_port_id(struct vport *p, char *buf)
{
	return sprintf(buf, "0x%x\n", 0);
}
static BRPORT_ATTR(port_id, S_IRUGO, show_port_id, NULL);

static ssize_t show_port_no(struct vport *p, char *buf)
{
	return sprintf(buf, "0x%x\n", p->port_no);
}

static BRPORT_ATTR(port_no, S_IRUGO, show_port_no, NULL);

static ssize_t show_change_ack(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(change_ack, S_IRUGO, show_change_ack, NULL);

static ssize_t show_config_pending(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(config_pending, S_IRUGO, show_config_pending, NULL);

static ssize_t show_port_state(struct vport *p, char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(state, S_IRUGO, show_port_state, NULL);

static ssize_t show_message_age_timer(struct vport *p,
					    char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(message_age_timer, S_IRUGO, show_message_age_timer, NULL);

static ssize_t show_forward_delay_timer(struct vport *p,
					    char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(forward_delay_timer, S_IRUGO, show_forward_delay_timer, NULL);

static ssize_t show_hold_timer(struct vport *p,
					    char *buf)
{
	return sprintf(buf, "%d\n", 0);
}
static BRPORT_ATTR(hold_timer, S_IRUGO, show_hold_timer, NULL);

static struct brport_attribute *brport_attrs[] = {
	&brport_attr_path_cost,
	&brport_attr_priority,
	&brport_attr_port_id,
	&brport_attr_port_no,
	&brport_attr_designated_root,
	&brport_attr_designated_bridge,
	&brport_attr_designated_port,
	&brport_attr_designated_cost,
	&brport_attr_state,
	&brport_attr_change_ack,
	&brport_attr_config_pending,
	&brport_attr_message_age_timer,
	&brport_attr_forward_delay_timer,
	&brport_attr_hold_timer,
	NULL
};

#define to_vport_attr(_at) container_of(_at, struct brport_attribute, attr)
#define to_vport(obj)	container_of(obj, struct vport, kobj)

static ssize_t brport_show(struct kobject * kobj,
			   struct attribute * attr, char * buf)
{
	struct brport_attribute * brport_attr = to_vport_attr(attr);
	struct vport * p = to_vport(kobj);

	return brport_attr->show(p, buf);
}

static ssize_t brport_store(struct kobject * kobj,
			    struct attribute * attr,
			    const char * buf, size_t count)
{
	struct vport * p = to_vport(kobj);
	ssize_t ret = -EINVAL;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	printk("%s: xxx writing port parms not supported yet!\n",
	       dp_name(p->dp));

	return ret;
}

struct sysfs_ops brport_sysfs_ops = {
	.show = brport_show,
	.store = brport_store,
};

/*
 * Add sysfs entries to ethernet device added to a bridge.
 * Creates a brport subdirectory with bridge attributes.
 * Puts symlink in bridge's brport subdirectory
 */
int dp_sysfs_add_if(struct vport *p)
{
	struct kobject *kobj = vport_get_kobj(p);
	struct datapath *dp = p->dp;
	struct brport_attribute **a;
	int err;

	/* Create /sys/class/net/<devname>/brport directory. */
	if (!kobj)
		return -ENOENT;

	err = kobject_add(&p->kobj, kobj, SYSFS_BRIDGE_PORT_ATTR);
	if (err)
		goto err;

	/* Create symlink from /sys/class/net/<devname>/brport/bridge to
	 * /sys/class/net/<bridgename>. */
	err = sysfs_create_link(&p->kobj,
		vport_get_kobj(rtnl_dereference(dp->ports[ODPP_LOCAL])),
		SYSFS_BRIDGE_PORT_LINK); /* "bridge" */
	if (err)
		goto err_del;

	/* Populate /sys/class/net/<devname>/brport directory with files. */
	for (a = brport_attrs; *a; ++a) {
		err = sysfs_create_file(&p->kobj, &((*a)->attr));
		if (err)
			goto err_del;
	}

	/* Create symlink from /sys/class/net/<bridgename>/brif/<devname> to
	 * /sys/class/net/<devname>/brport.  */
	err = sysfs_create_link(&dp->ifobj, &p->kobj, vport_get_name(p));
	if (err)
		goto err_del;
	strcpy(p->linkname, vport_get_name(p));

	kobject_uevent(&p->kobj, KOBJ_ADD);

	return 0;

err_del:
	kobject_del(&p->kobj);
err:
	p->linkname[0] = 0;
	return err;
}

int dp_sysfs_del_if(struct vport *p)
{
	if (p->linkname[0]) {
		sysfs_remove_link(&p->dp->ifobj, p->linkname);
		kobject_uevent(&p->kobj, KOBJ_REMOVE);
		kobject_del(&p->kobj);
		p->linkname[0] = '\0';
	}
	return 0;
}
#endif /* CONFIG_SYSFS */