/*
 * swconfig.c: Switch configuration API
 *
 * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.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; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/switch.h>

//#define DEBUG 1
#ifdef DEBUG
#define DPRINTF(format, ...) printk("%s: " format, __func__, ##__VA_ARGS__)
#else
#define DPRINTF(...) do {} while(0)
#endif

MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
MODULE_LICENSE("GPL");

static int swdev_id = 0;
static struct list_head swdevs;
static spinlock_t swdevs_lock = SPIN_LOCK_UNLOCKED;
struct swconfig_callback;

struct swconfig_callback
{
	struct sk_buff *msg;
	struct genlmsghdr *hdr;
	struct genl_info *info;
	int cmd;

	/* callback for filling in the message data */
	int (*fill)(struct swconfig_callback *cb, void *arg);

	/* callback for closing the message before sending it */
	int (*close)(struct swconfig_callback *cb, void *arg);

	struct nlattr *nest[4];
	int args[4];
};

/* defaults */

static int
swconfig_get_vlan_ports(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	int ret;
	if (val->port_vlan >= dev->vlans)
		return -EINVAL;

	if (!dev->get_vlan_ports)
		return -EOPNOTSUPP;

	ret = dev->get_vlan_ports(dev, val);
	return ret;
}

static int
swconfig_set_vlan_ports(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	struct switch_port *ports = val->value.ports;
	int i;

	if (val->port_vlan >= dev->vlans)
		return -EINVAL;

	/* validate ports */
	if (val->len > dev->ports)
		return -EINVAL;

	if (!dev->set_vlan_ports)
		return -EOPNOTSUPP;

	for (i = 0; i < val->len; i++) {
		if (ports[i].id >= dev->ports)
			return -EINVAL;

		if (dev->set_port_pvid && !(ports[i].flags & SWITCH_PORT_FLAG_TAGGED))
			dev->set_port_pvid(dev, ports[i].id, val->port_vlan);
	}

	return dev->set_vlan_ports(dev, val);
}

static int
swconfig_set_pvid(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	if (val->port_vlan >= dev->ports)
		return -EINVAL;

	if (!dev->set_port_pvid)
		return -EOPNOTSUPP;

	return dev->set_port_pvid(dev, val->port_vlan, val->value.i);
}

static int
swconfig_get_pvid(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	if (val->port_vlan >= dev->ports)
		return -EINVAL;

	if (!dev->get_port_pvid)
		return -EOPNOTSUPP;

	return dev->get_port_pvid(dev, val->port_vlan, &val->value.i);
}

static int
swconfig_apply_config(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	/* don't complain if not supported by the switch driver */
	if (!dev->apply_config)
		return 0;

	return dev->apply_config(dev);
}

static int
swconfig_reset_switch(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val)
{
	/* don't complain if not supported by the switch driver */
	if (!dev->reset_switch)
		return 0;

	return dev->reset_switch(dev);
}

enum global_defaults {
	GLOBAL_APPLY,
	GLOBAL_RESET,
};

enum vlan_defaults {
	VLAN_PORTS,
};

enum port_defaults {
	PORT_PVID,
};

static struct switch_attr default_global[] = {
	[GLOBAL_APPLY] = {
		.type = SWITCH_TYPE_NOVAL,
		.name = "apply",
		.description = "Activate changes in the hardware",
		.set = swconfig_apply_config,
	},
	[GLOBAL_RESET] = {
		.type = SWITCH_TYPE_NOVAL,
		.name = "reset",
		.description = "Reset the switch",
		.set = swconfig_reset_switch,
	}
};

static struct switch_attr default_port[] = {
	[PORT_PVID] = {
		.type = SWITCH_TYPE_INT,
		.name = "pvid",
		.description = "Primary VLAN ID",
		.set = swconfig_set_pvid,
		.get = swconfig_get_pvid,
	}
};

static struct switch_attr default_vlan[] = {
	[VLAN_PORTS] = {
		.type = SWITCH_TYPE_PORTS,
		.name = "ports",
		.description = "VLAN port mapping",
		.set = swconfig_set_vlan_ports,
		.get = swconfig_get_vlan_ports,
	},
};


static void swconfig_defaults_init(struct switch_dev *dev)
{
	dev->def_global = 0;
	dev->def_vlan = 0;
	dev->def_port = 0;

	if (dev->get_vlan_ports || dev->set_vlan_ports)
		set_bit(VLAN_PORTS, &dev->def_vlan);

	if (dev->get_port_pvid || dev->set_port_pvid)
		set_bit(PORT_PVID, &dev->def_port);

	/* always present, can be no-op */
	set_bit(GLOBAL_APPLY, &dev->def_global);
	set_bit(GLOBAL_RESET, &dev->def_global);
}


static struct genl_family switch_fam = {
	.id = GENL_ID_GENERATE,
	.name = "switch",
	.hdrsize = 0,
	.version = 1,
	.maxattr = SWITCH_ATTR_MAX,
};

static const struct nla_policy switch_policy[SWITCH_ATTR_MAX+1] = {
	[SWITCH_ATTR_ID] = { .type = NLA_U32 },
	[SWITCH_ATTR_OP_ID] = { .type = NLA_U32 },
	[SWITCH_ATTR_OP_PORT] = { .type = NLA_U32 },
	[SWITCH_ATTR_OP_VLAN] = { .type = NLA_U32 },
	[SWITCH_ATTR_OP_VALUE_INT] = { .type = NLA_U32 },
	[SWITCH_ATTR_OP_VALUE_STR] = { .type = NLA_NUL_STRING },
	[SWITCH_ATTR_OP_VALUE_PORTS] = { .type = NLA_NESTED },
	[SWITCH_ATTR_TYPE] = { .type = NLA_U32 },
};

static const struct nla_policy port_policy[SWITCH_PORT_ATTR_MAX+1] = {
	[SWITCH_PORT_ID] = { .type = NLA_U32 },
	[SWITCH_PORT_FLAG_TAGGED] = { .type = NLA_FLAG },
};

static inline void
swconfig_lock(void)
{
	spin_lock(&swdevs_lock);
}

static inline void
swconfig_unlock(void)
{
	spin_unlock(&swdevs_lock);
}

static struct switch_dev *
swconfig_get_dev(struct genl_info *info)
{
	struct switch_dev *dev = NULL;
	struct switch_dev *p;
	int id;

	if (!info->attrs[SWITCH_ATTR_ID])
		goto done;

	id = nla_get_u32(info->attrs[SWITCH_ATTR_ID]);
	swconfig_lock();
	list_for_each_entry(p, &swdevs, dev_list) {
		if (id != p->id)
			continue;

		dev = p;
		break;
	}
	if (dev)
		spin_lock(&dev->lock);
	else
		DPRINTF("device %d not found\n", id);
	swconfig_unlock();
done:
	return dev;
}

static inline void
swconfig_put_dev(struct switch_dev *dev)
{
	spin_unlock(&dev->lock);
}

static int
swconfig_dump_attr(struct swconfig_callback *cb, void *arg)
{
	struct switch_attr *op = arg;
	struct genl_info *info = cb->info;
	struct sk_buff *msg = cb->msg;
	int id = cb->args[0];
	void *hdr;

	hdr = genlmsg_put(msg, info->snd_pid, info->snd_seq, &switch_fam,
			NLM_F_MULTI, SWITCH_CMD_NEW_ATTR);
	if (IS_ERR(hdr))
		return -1;

	NLA_PUT_U32(msg, SWITCH_ATTR_OP_ID, id);
	NLA_PUT_U32(msg, SWITCH_ATTR_OP_TYPE, op->type);
	NLA_PUT_STRING(msg, SWITCH_ATTR_OP_NAME, op->name);
	if (op->description)
		NLA_PUT_STRING(msg, SWITCH_ATTR_OP_DESCRIPTION,
			op->description);

	return genlmsg_end(msg, hdr);
nla_put_failure:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

/* spread multipart messages across multiple message buffers */
static int
swconfig_send_multipart(struct swconfig_callback *cb, void *arg)
{
	struct genl_info *info = cb->info;
	int restart = 0;
	int err;

	do {
		if (!cb->msg) {
			cb->msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
			if (cb->msg == NULL)
				goto error;
		}

		if (!(cb->fill(cb, arg) < 0))
			break;

		/* fill failed, check if this was already the second attempt */
		if (restart)
			goto error;

		/* try again in a new message, send the current one */
		restart = 1;
		if (cb->close) {
			if (cb->close(cb, arg) < 0)
				goto error;
		}
		err = genlmsg_unicast(cb->msg, info->snd_pid);
		cb->msg = NULL;
		if (err < 0)
			goto error;

	} while (restart);

	return 0;

error:
	if (cb->msg)
		nlmsg_free(cb->msg);
	return -1;
}

static int
swconfig_list_attrs(struct sk_buff *skb, struct genl_info *info)
{
	struct genlmsghdr *hdr = nlmsg_data(info->nlhdr);
	const struct switch_attrlist *alist;
	struct switch_dev *dev;
	struct swconfig_callback cb;
	int err = -EINVAL;
	int i;

	/* defaults */
	struct switch_attr *def_list;
	unsigned long *def_active;
	int n_def;

	dev = swconfig_get_dev(info);
	if (!dev)
		return -EINVAL;

	switch(hdr->cmd) {
	case SWITCH_CMD_LIST_GLOBAL:
		alist = &dev->attr_global;
		def_list = default_global;
		def_active = &dev->def_global;
		n_def = ARRAY_SIZE(default_global);
		break;
	case SWITCH_CMD_LIST_VLAN:
		alist = &dev->attr_vlan;
		def_list = default_vlan;
		def_active = &dev->def_vlan;
		n_def = ARRAY_SIZE(default_vlan);
		break;
	case SWITCH_CMD_LIST_PORT:
		alist = &dev->attr_port;
		def_list = default_port;
		def_active = &dev->def_port;
		n_def = ARRAY_SIZE(default_port);
		break;
	default:
		WARN_ON(1);
		goto out;
	}

	memset(&cb, 0, sizeof(cb));
	cb.info = info;
	cb.fill = swconfig_dump_attr;
	for (i = 0; i < alist->n_attr; i++) {
		if (alist->attr[i].disabled)
			continue;
		cb.args[0] = i;
		err = swconfig_send_multipart(&cb, (void *) &alist->attr[i]);
		if (err < 0)
			goto error;
	}

	/* defaults */
	for (i = 0; i < n_def; i++) {
		if (!test_bit(i, def_active))
			continue;
		cb.args[0] = SWITCH_ATTR_DEFAULTS_OFFSET + i;
		err = swconfig_send_multipart(&cb, (void *) &def_list[i]);
		if (err < 0)
			goto error;
	}
	swconfig_put_dev(dev);

	if (!cb.msg)
		return 0;

	return genlmsg_unicast(cb.msg, info->snd_pid);

error:
	if (cb.msg)
		nlmsg_free(cb.msg);
out:
	swconfig_put_dev(dev);
	return err;
}

static const struct switch_attr *
swconfig_lookup_attr(struct switch_dev *dev, struct genl_info *info,
		struct switch_val *val)
{
	struct genlmsghdr *hdr = nlmsg_data(info->nlhdr);
	const struct switch_attrlist *alist;
	const struct switch_attr *attr = NULL;
	int attr_id;

	/* defaults */
	struct switch_attr *def_list;
	unsigned long *def_active;
	int n_def;

	if (!info->attrs[SWITCH_ATTR_OP_ID])
		goto done;

	switch(hdr->cmd) {
	case SWITCH_CMD_SET_GLOBAL:
	case SWITCH_CMD_GET_GLOBAL:
		alist = &dev->attr_global;
		def_list = default_global;
		def_active = &dev->def_global;
		n_def = ARRAY_SIZE(default_global);
		break;
	case SWITCH_CMD_SET_VLAN:
	case SWITCH_CMD_GET_VLAN:
		alist = &dev->attr_vlan;
		def_list = default_vlan;
		def_active = &dev->def_vlan;
		n_def = ARRAY_SIZE(default_vlan);
		if (!info->attrs[SWITCH_ATTR_OP_VLAN])
			goto done;
		val->port_vlan = nla_get_u32(info->attrs[SWITCH_ATTR_OP_VLAN]);
		if (val->port_vlan >= dev->vlans)
			goto done;
		break;
	case SWITCH_CMD_SET_PORT:
	case SWITCH_CMD_GET_PORT:
		alist = &dev->attr_port;
		def_list = default_port;
		def_active = &dev->def_port;
		n_def = ARRAY_SIZE(default_port);
		if (!info->attrs[SWITCH_ATTR_OP_PORT])
			goto done;
		val->port_vlan = nla_get_u32(info->attrs[SWITCH_ATTR_OP_PORT]);
		if (val->port_vlan >= dev->ports)
			goto done;
		break;
	default:
		WARN_ON(1);
		goto done;
	}

	if (!alist)
		goto done;

	attr_id = nla_get_u32(info->attrs[SWITCH_ATTR_OP_ID]);
	if (attr_id >= SWITCH_ATTR_DEFAULTS_OFFSET) {
		attr_id -= SWITCH_ATTR_DEFAULTS_OFFSET;
		if (attr_id >= n_def)
			goto done;
		if (!test_bit(attr_id, def_active))