/*
 * net/core/devlink.c - Network physical/parent device Netlink interface
 *
 * Heavily inspired by net/wireless/
 * Copyright (c) 2016 Mellanox Technologies. All rights reserved.
 * Copyright (c) 2016 Jiri Pirko <jiri@mellanox.com>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/gfp.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <rdma/ib_verbs.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include <net/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/devlink.h>

static LIST_HEAD(devlink_list);

/* devlink_mutex
 *
 * An overall lock guarding every operation coming from userspace.
 * It also guards devlink devices list and it is taken when
 * driver registers/unregisters it.
 */
static DEFINE_MUTEX(devlink_mutex);

/* devlink_port_mutex
 *
 * Shared lock to guard lists of ports in all devlink devices.
 */
static DEFINE_MUTEX(devlink_port_mutex);

static struct net *devlink_net(const struct devlink *devlink)
{
	return read_pnet(&devlink->_net);
}

static void devlink_net_set(struct devlink *devlink, struct net *net)
{
	write_pnet(&devlink->_net, net);
}

static struct devlink *devlink_get_from_attrs(struct net *net,
					      struct nlattr **attrs)
{
	struct devlink *devlink;
	char *busname;
	char *devname;

	if (!attrs[DEVLINK_ATTR_BUS_NAME] || !attrs[DEVLINK_ATTR_DEV_NAME])
		return ERR_PTR(-EINVAL);

	busname = nla_data(attrs[DEVLINK_ATTR_BUS_NAME]);
	devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]);

	list_for_each_entry(devlink, &devlink_list, list) {
		if (strcmp(devlink->dev->bus->name, busname) == 0 &&
		    strcmp(dev_name(devlink->dev), devname) == 0 &&
		    net_eq(devlink_net(devlink), net))
			return devlink;
	}

	return ERR_PTR(-ENODEV);
}

static struct devlink *devlink_get_from_info(struct genl_info *info)
{
	return devlink_get_from_attrs(genl_info_net(info), info->attrs);
}

static struct devlink_port *devlink_port_get_by_index(struct devlink *devlink,
						      int port_index)
{
	struct devlink_port *devlink_port;

	list_for_each_entry(devlink_port, &devlink->port_list, list) {
		if (devlink_port->index == port_index)
			return devlink_port;
	}
	return NULL;
}

static bool devlink_port_index_exists(struct devlink *devlink, int port_index)
{
	return devlink_port_get_by_index(devlink, port_index);
}

static struct devlink_port *devlink_port_get_from_attrs(struct devlink *devlink,
							struct nlattr **attrs)
{
	if (attrs[DEVLINK_ATTR_PORT_INDEX]) {
		u32 port_index = nla_get_u32(attrs[DEVLINK_ATTR_PORT_INDEX]);
		struct devlink_port *devlink_port;

		devlink_port = devlink_port_get_by_index(devlink, port_index);
		if (!devlink_port)
			return ERR_PTR(-ENODEV);
		return devlink_port;
	}
	return ERR_PTR(-EINVAL);
}

static struct devlink_port *devlink_port_get_from_info(struct devlink *devlink,
						       struct genl_info *info)
{
	return devlink_port_get_from_attrs(devlink, info->attrs);
}

#define DEVLINK_NL_FLAG_NEED_PORT	BIT(0)

static int devlink_nl_pre_doit(const struct genl_ops *ops,
			       struct sk_buff *skb, struct genl_info *info)
{
	struct devlink *devlink;

	mutex_lock(&devlink_mutex);
	devlink = devlink_get_from_info(info);
	if (IS_ERR(devlink)) {
		mutex_unlock(&devlink_mutex);
		return PTR_ERR(devlink);
	}
	info->user_ptr[0] = devlink;
	if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_PORT) {
		struct devlink_port *devlink_port;

		mutex_lock(&devlink_port_mutex);
		devlink_port = devlink_port_get_from_info(devlink, info);
		if (IS_ERR(devlink_port)) {
			mutex_unlock(&devlink_port_mutex);
			mutex_unlock(&devlink_mutex);
			return PTR_ERR(devlink_port);
		}
		info->user_ptr[1] = devlink_port;
	}
	return 0;
}

static void devlink_nl_post_doit(const struct genl_ops *ops,
				 struct sk_buff *skb, struct genl_info *info)
{
	if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_PORT)
		mutex_unlock(&devlink_port_mutex);
	mutex_unlock(&devlink_mutex);
}

static struct genl_family devlink_nl_family = {
	.id		= GENL_ID_GENERATE,
	.name		= DEVLINK_GENL_NAME,
	.version	= DEVLINK_GENL_VERSION,
	.maxattr	= DEVLINK_ATTR_MAX,
	.netnsok	= true,
	.pre_doit	= devlink_nl_pre_doit,
	.post_doit	= devlink_nl_post_doit,
};

enum devlink_multicast_groups {
	DEVLINK_MCGRP_CONFIG,
};

static const struct genl_multicast_group devlink_nl_mcgrps[] = {
	[DEVLINK_MCGRP_CONFIG] = { .name = DEVLINK_GENL_MCGRP_CONFIG_NAME },
};

static int devlink_nl_put_handle(struct sk_buff *msg, struct devlink *devlink)
{
	if (nla_put_string(msg, DEVLINK_ATTR_BUS_NAME, devlink->dev->bus->name))
		return -EMSGSIZE;
	if (nla_put_string(msg, DEVLINK_ATTR_DEV_NAME, dev_name(devlink->dev)))
		return -EMSGSIZE;
	return 0;
}

static int devlink_nl_fill(struct sk_buff *msg, struct devlink *devlink,
			   enum devlink_command cmd, u32 portid,
			   u32 seq, int flags)
{
	void *hdr;

	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
	if (!hdr)
		return -EMSGSIZE;

	if (devlink_nl_put_handle(msg, devlink))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

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

static void devlink_notify(struct devlink *devlink, enum devlink_command cmd)
{
	struct sk_buff *msg;
	int err;

	WARN_ON(cmd != DEVLINK_CMD_NEW && cmd != DEVLINK_CMD_DEL);

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return;

	err = devlink_nl_fill(msg, devlink, cmd, 0, 0, 0);
	if (err) {
		nlmsg_free(msg);
		return;
	}

	genlmsg_multicast_netns(&devlink_nl_family, devlink_net(devlink),
				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
}

static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink,
				struct devlink_port *devlink_port,
				enum devlink_command cmd, u32 portid,
				u32 seq, int flags)
{
	void *hdr;

	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
	if (!hdr)
		return -EMSGSIZE;

	if (devlink_nl_put_handle(msg, devlink))
		goto nla_put_failure;
	if (nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX, devlink_port->index))
		goto nla_put_failure;
	if (nla_put_u16(msg, DEVLINK_ATTR_PORT_TYPE, devlink_port->type))
		goto nla_put_failure;
	if (devlink_port->desired_type != DEVLINK_PORT_TYPE_NOTSET &&
	    nla_put_u16(msg, DEVLINK_ATTR_PORT_DESIRED_TYPE,
			devlink_port->desired_type))
		goto nla_put_failure;
	if (devlink_port->type == DEVLINK_PORT_TYPE_ETH) {
		struct net_device *netdev = devlink_port->type_dev;

		if (netdev &&
		    (nla_put_u32(msg, DEVLINK_ATTR_PORT_NETDEV_IFINDEX,
				 netdev->ifindex) ||
		     nla_put_string(msg, DEVLINK_ATTR_PORT_NETDEV_NAME,
				    netdev->name)))
			goto nla_put_failure;
	}
	if (devlink_port->type == DEVLINK_PORT_TYPE_IB) {
		struct ib_device *ibdev = devlink_port->type_dev;

		if (ibdev &&
		    nla_put_string(msg, DEVLINK_ATTR_PORT_IBDEV_NAME,
				   ibdev->name))
			goto nla_put_failure;
	}
	if (devlink_port->split &&
	    nla_put_u32(msg, DEVLINK_ATTR_PORT_SPLIT_GROUP,
			devlink_port->split_group))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

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

static void devlink_port_notify(struct devlink_port *devlink_port,
				enum devlink_command cmd)
{
	struct devlink *devlink = devlink_port->devlink;
	struct sk_buff *msg;
	int err;

	if (!devlink_port->registered)
		return;

	WARN_ON(cmd != DEVLINK_CMD_PORT_NEW && cmd != DEVLINK_CMD_PORT_DEL);

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return;

	err = devlink_nl_port_fill(msg, devlink, devlink_port, cmd, 0, 0, 0);
	if (err) {
		nlmsg_free(msg);
		return;
	}

	genlmsg_multicast_netns(&devlink_nl_family, devlink_net(devlink),
				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
}

static int devlink_nl_cmd_get_doit(struct sk_buff *skb, struct genl_info *info)
{
	struct devlink *devlink = info->user_ptr[0];
	struct sk_buff *msg;
	int err;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	err = devlink_nl_fill(msg, devlink, DEVLINK_CMD_NEW,
			      info->snd_portid, info->snd_seq, 0);
	if (err) {
		nlmsg_free(msg);
		return err;
	}

	return genlmsg_reply(msg, info);
}

static int devlink_nl_cmd_get_dumpit(struct sk_buff *msg,
				     struct netlink_callback *cb)
{
	struct devlink *devlink;
	int start = cb->args[0];
	int idx = 0;
	int err;

	mutex_lock(&devlink_mutex);
	list_for_each_entry(devlink, &devlink_list, list) {
		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
			continue;
		if (idx < start) {
			idx++;
			continue;
		}
		err = devlink_nl_fill(msg, devlink, DEVLINK_CMD_NEW,
				      NETLINK_CB(cb->skb).portid,
				      cb->nlh->nlmsg_seq, NLM_F_MULTI);
		if (err)
			goto out;
		idx++;
	}
out:
	mutex_unlock(&devlink_mutex);

	cb->args[0] = idx;
	return msg->len;
}

static int devlink_nl_cmd_port_get_doit(struct sk_buff *skb,
					struct genl_info *info)
{
	struct devlink *devlink = info->user_ptr[0];
	struct devlink_port *devlink_port = info->user_ptr[1];
	struct sk_buff *msg;
	int err;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	err = devlink_nl_port_fill(msg, devlink, devlink_port,
				   DEVLINK_CMD_PORT_NEW,
				   info->snd_portid, info->snd_seq, 0);
	if (err) {
		nlmsg_free(msg);
		return err;
	}

	return genlmsg_reply(msg, info);
}

static int devlink_nl_cmd_port_get_dumpit(struct sk_buff *msg,
					  struct netlink_callback *cb)
{
	struct devlink *devlink;
	struct devlink_port *devlink_port;
	int start = cb->args[0];
	int idx = 0;
	int err;

	mutex_lock(&devlink_mutex);
	mutex_lock(&devlink_port_mutex);
	list_for_each_entry(devlink, &devlink_list, list) {
		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
			continue;
		list_for_each_entry(devlink_port, &devlink->port_list, list) {
			if (idx < start) {
				idx++;
				continue;
			}
			err = devlink_nl_port_fill(msg, devlink, devlink_port,
						   DEVLINK_CMD_NEW,
						   NETLINK_CB(cb->skb).portid,
						   cb->nlh->nlmsg_seq,
						   NLM_F_MULTI);
			if (err)
				goto out;
			idx++;
		}
	}
out:
	mutex_unlock(&devlink_port_mutex);
	mutex_unlock(&devlink_mutex);

	cb->args[0] = idx;
	return msg->len;
}

static int devlink_port_type_set(struct devlink *devlink,
				 struct devlink_port *devlink_port,
				 enum devlink_port_type port_type)

{
	int err;

	if (devlink->ops && devlink->ops->port_type_set) {
		if (port_type == DEVLINK_PORT_TYPE_NOTSET)
			return -EINVAL;
		err = devlink->ops->port_type_set(devlink_port, port_type);
		if (err)
			return err;
		devlink_port->desired_type = port_type;
		devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
		return 0;
	}
	return -EOPNOTSUPP;
}

static int devlink_nl_cmd_port_set_doit(struct sk_buff *skb,
					struct genl_info *info)
{
	struct devlink *devlink = info->user_ptr[0];
	struct devlink_port *devlink_port = info->user_ptr[1];
	int err;

	if (info->attrs[DEVLINK_ATTR_PORT_TYPE]) {
		enum devlink_port_type port_type;

		port_type = nla_get_u16(info->attrs[DEVLINK_ATTR_PORT_TYPE]);
		err = devlink_port_type_set(devlink, devlink_port, port_type);
		if (err)
			return err;
	}
	return 0;
}

static int devlink_port_split(struct devlink *devlink,
			      u32 port_index, u32 count)

{
	if (devlink->ops && devlink->ops->port_split)
		return devlink->ops->port_split(devlink, port_index, count);
	return -EOPNOTSUPP;
}

static int devlink_nl_cmd_port_split_doit(struct sk_buff *skb,
					  struct genl_info *info)
{
	struct devlink *devlink = info->user_ptr[0];
	u32 port_index;
	u32 count;

	if (!info->attrs[DEVLINK_ATTR_PORT_INDEX] ||
	    !info->attrs[DEVLINK_ATTR_PORT_SPLIT_COUNT])
		return -EINVAL;

	port_index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
	count = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_SPLIT_COUNT]);
	return devlink_port_split(devlink, port_index, count);
}

static int devlink_port_unsplit(struct devlink *devlink, u32 port_index)

{
	if (devlink->ops && devlink->ops->port_unsplit)
		return devlink->ops->port_unsplit(devlink, port_index);
	return -EOPNOTSUPP;
}

static int devlink_nl_cmd_port_unsplit_doit(struct sk_buff *skb,
					    struct genl_info *info)
{
	struct devlink *devlink = info->user_ptr[0];
	u32 port_index;

	if (!info->attrs[DEVLINK_ATTR_PORT_INDEX])
		return -EINVAL;

	port_index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
	return devlink_port_unsplit(devlink, port_index);
}

static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
	[DEVLINK_ATTR_PORT_INDEX] = { .type = NLA_U32 },
	[DEVLINK_ATTR_PORT_TYPE] = { .type = NLA_U16 },
	[DEVLINK_ATTR_PORT_SPLIT_COUNT] = { .type = NLA_U32 },
};

static const struct genl_ops devlink_nl_ops[] = {
	{
		.cmd = DEVLINK_CMD_GET,
		.doit = devlink_nl_cmd_get_doit,
		.dumpit = devlink_nl_cmd_get_dumpit,
		.policy = devlink_nl_policy,
		/* can be retrieved by unprivileged users */
	},
	{
		.cmd = DEVLINK_CMD_PORT_GET,
		.doit = devlink_nl_cmd_port_get_doit,
		.dumpit = devlink_nl_cmd_port_get_dumpit,
		.policy = devlink_nl_policy,
		.internal_flags = DEVLINK_NL_FLAG_NEED_PORT,
		/* can be retrieved by unprivileged users */
	},
	{
		.cmd = DEVLINK_CMD_PORT_SET,
		.doit = devlink_nl_cmd_port_set_doit,
		.policy = devlink_nl_policy,
		.flags = GENL_ADMIN_PERM,
		.internal_flags = DEVLINK_NL_FLAG_NEED_PORT,
	},
	{
		.cmd = DEVLINK_CMD_PORT_SPLIT,
		.doit = devlink_nl_cmd_port_split_doit,
		.policy = devlink_nl_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = DEVLINK_CMD_PORT_UNSPLIT,
		.doit = devlink_nl_cmd_port_unsplit_doit,
		.policy = devlink_nl_policy,
		.flags = GENL_ADMIN_PERM,
	},
};

/**
 *	devlink_alloc - Allocate new devlink instance resources
 *
 *	@ops: ops
 *	@priv_size: size of user private data
 *
 *	Allocate new devlink instance resources, including devlink index
 *	and name.
 */
struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size)
{
	struct devlink *devlink;

	devlink = kzalloc(sizeof(*devlink) + priv_size, GFP_KERNEL);
	if (!devlink)
		return NULL;
	devlink->ops = ops;
	devlink_net_set(devlink, &init_net);
	INIT_LIST_HEAD(&devlink->port_list);
	return devlink;
}
EXPORT_SYMBOL_GPL(devlink_alloc);

/**
 *	devlink_register - Register devlink instance
 *
 *	@devlink: devlink
 */
int devlink_register(struct devlink *devlink, struct device *dev)
{
	mutex_lock(&devlink_mutex);
	devlink->dev = dev;
	list_add_tail(&devlink->list, &devlink_list);
	devlink_notify(devlink, DEVLINK_CMD_NEW);
	mutex_unlock(&devlink_mutex);
	return 0;
}
EXPORT_SYMBOL_GPL(devlink_register);

/**
 *	devlink_unregister - Unregister devlink instance
 *
 *	@devlink: devlink
 */
void devlink_unregister(struct devlink *devlink)
{
	mutex_lock(&devlink_mutex);
	devlink_notify(devlink, DEVLINK_CMD_DEL);
	list_del(&devlink->list);
	mutex_unlock(&devlink_mutex);
}
EXPORT_SYMBOL_GPL(devlink_unregister);

/**
 *	devlink_free - Free devlink instance resources
 *
 *	@devlink: devlink
 */
void devlink_free(struct devlink *devlink)
{
	kfree(devlink);
}
EXPORT_SYMBOL_GPL(devlink_free);

/**
 *	devlink_port_register - Register devlink port
 *
 *	@devlink: devlink
 *	@devlink_port: devlink port
 *	@port_index
 *
 *	Register devlink port with provided port index. User can use
 *	any indexing, even hw-related one. devlink_port structure
 *	is convenient to be embedded inside user driver private structure.
 *	Note that the caller should take care of zeroing the devlink_port
 *	structure.
 */
int devlink_port_register(struct devlink *devlink,
			  struct devlink_port *devlink_port,
			  unsigned int port_index)
{
	mutex_lock(&devlink_port_mutex);
	if (devlink_port_index_exists(devlink, port_index)) {
		mutex_unlock(&devlink_port_mutex);
		return -EEXIST;
	}
	devlink_port->devlink = devlink;
	devlink_port->index = port_index;
	devlink_port->type = DEVLINK_PORT_TYPE_NOTSET;
	devlink_port->registered = true;
	list_add_tail(&devlink_port->list, &devlink->port_list);
	mutex_unlock(&devlink_port_mutex);
	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
	return 0;
}
EXPORT_SYMBOL_GPL(devlink_port_register);

/**
 *	devlink_port_unregister - Unregister devlink port
 *
 *	@devlink_port: devlink port
 */
void devlink_port_unregister(struct devlink_port *devlink_port)
{
	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_DEL);
	mutex_lock(&devlink_port_mutex);
	list_del(&devlink_port->list);
	mutex_unlock(&devlink_port_mutex);
}
EXPORT_SYMBOL_GPL(devlink_port_unregister);

static void __devlink_port_type_set(struct devlink_port *devlink_port,
				    enum devlink_port_type type,
				    void *type_dev)
{
	devlink_port->type = type;
	devlink_port->type_dev = type_dev;
	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
}

/**
 *	devlink_port_type_eth_set - Set port type to Ethernet
 *
 *	@devlink_port: devlink port
 *	@netdev: related netdevice
 */
void devlink_port_type_eth_set(struct devlink_port *devlink_port,
			       struct net_device *netdev)
{
	return __devlink_port_type_set(devlink_port,
				       DEVLINK_PORT_TYPE_ETH, netdev);
}
EXPORT_SYMBOL_GPL(devlink_port_type_eth_set);

/**
 *	devlink_port_type_ib_set - Set port type to InfiniBand
 *
 *	@devlink_port: devlink port
 *	@ibdev: related IB device
 */
void devlink_port_type_ib_set(struct devlink_port *devlink_port,
			      struct ib_device *ibdev)
{
	return __devlink_port_type_set(devlink_port,
				       DEVLINK_PORT_TYPE_IB, ibdev);
}
EXPORT_SYMBOL_GPL(devlink_port_type_ib_set);

/**
 *	devlink_port_type_clear - Clear port type
 *
 *	@devlink_port: devlink port
 */
void devlink_port_type_clear(struct devlink_port *devlink_port)
{
	return __devlink_port_type_set(devlink_port,
				       DEVLINK_PORT_TYPE_NOTSET, NULL);
}
EXPORT_SYMBOL_GPL(devlink_port_type_clear);

/**
 *	devlink_port_split_set - Set port is split
 *
 *	@devlink_port: devlink port
 *	@split_group: split group - identifies group split port is part of
 */
void devlink_port_split_set(struct devlink_port *devlink_port,
			    u32 split_group)
{
	devlink_port->split = true;
	devlink_port->split_group = split_group;
	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
}
EXPORT_SYMBOL_GPL(devlink_port_split_set);

static int __init devlink_module_init(void)
{
	return genl_register_family_with_ops_groups(&devlink_nl_family,
						    devlink_nl_ops,
						    devlink_nl_mcgrps);
}

static void __exit devlink_module_exit(void)
{
	genl_unregister_family(&devlink_nl_family);
}

module_init(devlink_module_init);
module_exit(devlink_module_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
MODULE_DESCRIPTION("Network physical device Netlink interface");
MODULE_ALIAS_GENL_FAMILY(DEVLINK_GENL_NAME);