/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * include/net/l3mdev.h - L3 master device API
 * Copyright (c) 2015 Cumulus Networks
 * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
 */
#ifndef _NET_L3MDEV_H_
#define _NET_L3MDEV_H_

#include <net/dst.h>
#include <net/fib_rules.h>

enum l3mdev_type {
        L3MDEV_TYPE_UNSPEC,
        L3MDEV_TYPE_VRF,
        __L3MDEV_TYPE_MAX
};

#define L3MDEV_TYPE_MAX (__L3MDEV_TYPE_MAX - 1)

typedef int (*lookup_by_table_id_t)(struct net *net, u32 table_d);

/**
 * struct l3mdev_ops - l3mdev operations
 *
 * @l3mdev_fib_table: Get FIB table id to use for lookups
 *
 * @l3mdev_l3_rcv:    Hook in L3 receive path
 *
 * @l3mdev_l3_out:    Hook in L3 output path
 *
 * @l3mdev_link_scope_lookup: IPv6 lookup for linklocal and mcast destinations
 */

struct l3mdev_ops {
        u32             (*l3mdev_fib_table)(const struct net_device *dev);
        struct sk_buff * (*l3mdev_l3_rcv)(struct net_device *dev,
                                          struct sk_buff *skb, u16 proto);
        struct sk_buff * (*l3mdev_l3_out)(struct net_device *dev,
                                          struct sock *sk, struct sk_buff *skb,
                                          u16 proto);

        /* IPv6 ops */
        struct dst_entry * (*l3mdev_link_scope_lookup)(const struct net_device *dev,
                                                 struct flowi6 *fl6);
};

#ifdef CONFIG_NET_L3_MASTER_DEV

int l3mdev_table_lookup_register(enum l3mdev_type l3type,
                                 lookup_by_table_id_t fn);

void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
                                    lookup_by_table_id_t fn);

int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type, struct net *net,
                                      u32 table_id);

int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
                          struct fib_lookup_arg *arg);

static inline
bool l3mdev_fib_rule_iif_match(const struct flowi *fl, int iifindex)
{
        return !(fl->flowi_flags & FLOWI_FLAG_L3MDEV_OIF) &&
               fl->flowi_l3mdev == iifindex;
}

static inline
bool l3mdev_fib_rule_oif_match(const struct flowi *fl, int oifindex)
{
        return fl->flowi_flags & FLOWI_FLAG_L3MDEV_OIF &&
               fl->flowi_l3mdev == oifindex;
}

void l3mdev_update_flow(struct net *net, struct flowi *fl);

int l3mdev_master_ifindex_rcu(const struct net_device *dev);
static inline int l3mdev_master_ifindex(struct net_device *dev)
{
        int ifindex;

        rcu_read_lock();
        ifindex = l3mdev_master_ifindex_rcu(dev);
        rcu_read_unlock();

        return ifindex;
}

static inline int l3mdev_master_ifindex_by_index(struct net *net, int ifindex)
{
        struct net_device *dev;
        int rc = 0;

        if (ifindex) {
                rcu_read_lock();

                dev = dev_get_by_index_rcu(net, ifindex);
                if (dev)
                        rc = l3mdev_master_ifindex_rcu(dev);

                rcu_read_unlock();
        }

        return rc;
}

static inline
struct net_device *l3mdev_master_dev_rcu(const struct net_device *_dev)
{
        /* netdev_master_upper_dev_get_rcu calls
         * list_first_or_null_rcu to walk the upper dev list.
         * list_first_or_null_rcu does not handle a const arg. We aren't
         * making changes, just want the master device from that list so
         * typecast to remove the const
         */
        struct net_device *dev = (struct net_device *)_dev;
        struct net_device *master;

        if (!dev)
                return NULL;

        if (netif_is_l3_master(dev))
                master = dev;
        else if (netif_is_l3_slave(dev))
                master = netdev_master_upper_dev_get_rcu(dev);
        else
                master = NULL;

        return master;
}

int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex);
static inline
int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
{
        rcu_read_lock();
        ifindex = l3mdev_master_upper_ifindex_by_index_rcu(net, ifindex);
        rcu_read_unlock();

        return ifindex;
}

u32 l3mdev_fib_table_rcu(const struct net_device *dev);
u32 l3mdev_fib_table_by_index(struct net *net, int ifindex);
static inline u32 l3mdev_fib_table(const struct net_device *dev)
{
        u32 tb_id;

        rcu_read_lock();
        tb_id = l3mdev_fib_table_rcu(dev);
        rcu_read_unlock();

        return tb_id;
}

static inline bool netif_index_is_l3_master(struct net *net, int ifindex)
{
        struct net_device *dev;
        bool rc = false;

        if (ifindex == 0)
                return false;

        rcu_read_lock();

        dev = dev_get_by_index_rcu(net, ifindex);
        if (dev)
                rc = netif_is_l3_master(dev);

        rcu_read_unlock();

        return rc;
}

struct dst_entry *l3mdev_link_scope_lookup(struct net *net, struct flowi6 *fl6);

static inline
struct sk_buff *l3mdev_l3_rcv(struct sk_buff *skb, u16 proto)
{
        struct net_device *master = NULL;

        if (netif_is_l3_slave(skb->dev))
                master = netdev_master_upper_dev_get_rcu(skb->dev);
        else if (netif_is_l3_master(skb->dev) ||
                 netif_has_l3_rx_handler(skb->dev))
                master = skb->dev;

        if (master && master->l3mdev_ops->l3mdev_l3_rcv)
                skb = master->l3mdev_ops->l3mdev_l3_rcv(master, skb, proto);

        return skb;
}

static inline
struct sk_buff *l3mdev_ip_rcv(struct sk_buff *skb)
{
        return l3mdev_l3_rcv(skb, AF_INET);
}

static inline
struct sk_buff *l3mdev_ip6_rcv(struct sk_buff *skb)
{
        return l3mdev_l3_rcv(skb, AF_INET6);
}

static inline
struct sk_buff *l3mdev_l3_out(struct sock *sk, struct sk_buff *skb, u16 proto)
{
        struct net_device *dev;

        rcu_read_lock();
        dev = skb_dst_dev_rcu(skb);
        if (netif_is_l3_slave(dev)) {
                struct net_device *master;

                master = netdev_master_upper_dev_get_rcu(dev);
                if (master && master->l3mdev_ops->l3mdev_l3_out)
                        skb = master->l3mdev_ops->l3mdev_l3_out(master, sk,
                                                                skb, proto);
        }
        rcu_read_unlock();

        return skb;
}

static inline
struct sk_buff *l3mdev_ip_out(struct sock *sk, struct sk_buff *skb)
{
        return l3mdev_l3_out(sk, skb, AF_INET);
}

static inline
struct sk_buff *l3mdev_ip6_out(struct sock *sk, struct sk_buff *skb)
{
        return l3mdev_l3_out(sk, skb, AF_INET6);
}
#else

static inline int l3mdev_master_ifindex_rcu(const struct net_device *dev)
{
        return 0;
}
static inline int l3mdev_master_ifindex(struct net_device *dev)
{
        return 0;
}

static inline int l3mdev_master_ifindex_by_index(struct net *net, int ifindex)
{
        return 0;
}

static inline
int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
{
        return 0;
}
static inline
int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
{
        return 0;
}

static inline
struct net_device *l3mdev_master_dev_rcu(const struct net_device *dev)
{
        return NULL;
}

static inline u32 l3mdev_fib_table_rcu(const struct net_device *dev)
{
        return 0;
}
static inline u32 l3mdev_fib_table(const struct net_device *dev)
{
        return 0;
}
static inline u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
{
        return 0;
}

static inline bool netif_index_is_l3_master(struct net *net, int ifindex)
{
        return false;
}

static inline
struct dst_entry *l3mdev_link_scope_lookup(struct net *net, struct flowi6 *fl6)
{
        return NULL;
}

static inline
struct sk_buff *l3mdev_ip_rcv(struct sk_buff *skb)
{
        return skb;
}

static inline
struct sk_buff *l3mdev_ip6_rcv(struct sk_buff *skb)
{
        return skb;
}

static inline
struct sk_buff *l3mdev_ip_out(struct sock *sk, struct sk_buff *skb)
{
        return skb;
}

static inline
struct sk_buff *l3mdev_ip6_out(struct sock *sk, struct sk_buff *skb)
{
        return skb;
}

static inline
int l3mdev_table_lookup_register(enum l3mdev_type l3type,
                                 lookup_by_table_id_t fn)
{
        return -EOPNOTSUPP;
}

static inline
void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
                                    lookup_by_table_id_t fn)
{
}

static inline
int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type, struct net *net,
                                      u32 table_id)
{
        return -ENODEV;
}

static inline
int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
                          struct fib_lookup_arg *arg)
{
        return 1;
}

static inline
bool l3mdev_fib_rule_iif_match(const struct flowi *fl, int iifindex)
{
        return false;
}

static inline
bool l3mdev_fib_rule_oif_match(const struct flowi *fl, int oifindex)
{
        return false;
}

static inline
void l3mdev_update_flow(struct net *net, struct flowi *fl)
{
}
#endif

#endif /* _NET_L3MDEV_H_ */