/*
 *      Bridge per vlan tunnel port dst_metadata handling code
 *
 *      Authors:
 *      Roopa Prabhu            <roopa@cumulusnetworks.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/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <net/switchdev.h>
#include <net/dst_metadata.h>

#include "br_private.h"
#include "br_private_tunnel.h"

static inline int br_vlan_tunid_cmp(struct rhashtable_compare_arg *arg,
                                    const void *ptr)
{
        const struct net_bridge_vlan *vle = ptr;
        __be64 tunid = *(__be64 *)arg->key;

        return vle->tinfo.tunnel_id != tunid;
}

static const struct rhashtable_params br_vlan_tunnel_rht_params = {
        .head_offset = offsetof(struct net_bridge_vlan, tnode),
        .key_offset = offsetof(struct net_bridge_vlan, tinfo.tunnel_id),
        .key_len = sizeof(__be64),
        .nelem_hint = 3,
        .locks_mul = 1,
        .obj_cmpfn = br_vlan_tunid_cmp,
        .automatic_shrinking = true,
};

static struct net_bridge_vlan *br_vlan_tunnel_lookup(struct rhashtable *tbl,
                                                     u64 tunnel_id)
{
        return rhashtable_lookup_fast(tbl, &tunnel_id,
                                      br_vlan_tunnel_rht_params);
}

void vlan_tunnel_info_del(struct net_bridge_vlan_group *vg,
                          struct net_bridge_vlan *vlan)
{
        if (!vlan->tinfo.tunnel_dst)
                return;
        rhashtable_remove_fast(&vg->tunnel_hash, &vlan->tnode,
                               br_vlan_tunnel_rht_params);
        vlan->tinfo.tunnel_id = 0;
        dst_release(&vlan->tinfo.tunnel_dst->dst);
        vlan->tinfo.tunnel_dst = NULL;
}

static int __vlan_tunnel_info_add(struct net_bridge_vlan_group *vg,
                                  struct net_bridge_vlan *vlan, u32 tun_id)
{
        struct metadata_dst *metadata = NULL;
        __be64 key = key32_to_tunnel_id(cpu_to_be32(tun_id));
        int err;

        if (vlan->tinfo.tunnel_dst)
                return -EEXIST;

        metadata = __ip_tun_set_dst(0, 0, 0, 0, 0, TUNNEL_KEY,
                                    key, 0);
        if (!metadata)
                return -EINVAL;

        metadata->u.tun_info.mode |= IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_BRIDGE;
        vlan->tinfo.tunnel_dst = metadata;
        vlan->tinfo.tunnel_id = key;

        err = rhashtable_lookup_insert_fast(&vg->tunnel_hash, &vlan->tnode,
                                            br_vlan_tunnel_rht_params);
        if (err)
                goto out;

        return 0;
out:
        dst_release(&vlan->tinfo.tunnel_dst->dst);
        vlan->tinfo.tunnel_dst = NULL;
        vlan->tinfo.tunnel_id = 0;

        return err;
}

/* Must be protected by RTNL.
 * Must be called with vid in range from 1 to 4094 inclusive.
 */
int nbp_vlan_tunnel_info_add(struct net_bridge_port *port, u16 vid, u32 tun_id)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_vlan *vlan;

        ASSERT_RTNL();

        vg = nbp_vlan_group(port);
        vlan = br_vlan_find(vg, vid);
        if (!vlan)
                return -EINVAL;

        return __vlan_tunnel_info_add(vg, vlan, tun_id);
}

/* Must be protected by RTNL.
 * Must be called with vid in range from 1 to 4094 inclusive.
 */
int nbp_vlan_tunnel_info_delete(struct net_bridge_port *port, u16 vid)
{
        struct net_bridge_vlan_group *vg;
        struct net_bridge_vlan *v;

        ASSERT_RTNL();

        vg = nbp_vlan_group(port);
        v = br_vlan_find(vg, vid);
        if (!v)
                return -ENOENT;

        vlan_tunnel_info_del(vg, v);

        return 0;
}

static void __vlan_tunnel_info_flush(struct net_bridge_vlan_group *vg)
{
        struct net_bridge_vlan *vlan, *tmp;

        list_for_each_entry_safe(vlan, tmp, &vg->vlan_list, vlist)
                vlan_tunnel_info_del(vg, vlan);
}

void nbp_vlan_tunnel_info_flush(struct net_bridge_port *port)
{
        struct net_bridge_vlan_group *vg;

        ASSERT_RTNL();

        vg = nbp_vlan_group(port);
        __vlan_tunnel_info_flush(vg);
}

int vlan_tunnel_init(struct net_bridge_vlan_group *vg)
{
        return rhashtable_init(&vg->tunnel_hash, &br_vlan_tunnel_rht_params);
}

void vlan_tunnel_deinit(struct net_bridge_vlan_group *vg)
{
        rhashtable_destroy(&vg->tunnel_hash);
}

int br_handle_ingress_vlan_tunnel(struct sk_buff *skb,
                                  struct net_bridge_port *p,
                                  struct net_bridge_vlan_group *vg)
{
        struct ip_tunnel_info *tinfo = skb_tunnel_info(skb);
        struct net_bridge_vlan *vlan;

        if (!vg || !tinfo)
                return 0;

        /* if already tagged, ignore */
        if (skb_vlan_tagged(skb))
                return 0;

        /* lookup vid, given tunnel id */
        vlan = br_vlan_tunnel_lookup(&vg->tunnel_hash, tinfo->key.tun_id);
        if (!vlan)
                return 0;

        skb_dst_drop(skb);

        __vlan_hwaccel_put_tag(skb, p->br->vlan_proto, vlan->vid);

        return 0;
}

int br_handle_egress_vlan_tunnel(struct sk_buff *skb,
                                 struct net_bridge_vlan *vlan)
{
        int err;

        if (!vlan || !vlan->tinfo.tunnel_id)
                return 0;

        if (unlikely(!skb_vlan_tag_present(skb)))
                return 0;

        skb_dst_drop(skb);
        err = skb_vlan_pop(skb);
        if (err)
                return err;

        skb_dst_set(skb, dst_clone(&vlan->tinfo.tunnel_dst->dst));

        return 0;
}