/* Copyright (C) 2007-2016  B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "main.h"

#include <linux/atomic.h>
#include <linux/bug.h>
#include <linux/byteorder/generic.h>
#include <linux/crc32c.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <linux/pkt_sched.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <net/dsfield.h>
#include <net/rtnetlink.h>

#include "bat_algo.h"
#include "bridge_loop_avoidance.h"
#include "debugfs.h"
#include "distributed-arp-table.h"
#include "gateway_client.h"
#include "gateway_common.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "multicast.h"
#include "network-coding.h"
#include "originator.h"
#include "packet.h"
#include "routing.h"
#include "send.h"
#include "soft-interface.h"
#include "translation-table.h"

/* List manipulations on hardif_list have to be rtnl_lock()'ed,
 * list traversals just rcu-locked
 */
struct list_head batadv_hardif_list;
static int (*batadv_rx_handler[256])(struct sk_buff *,
                                     struct batadv_hard_iface *);
char batadv_routing_algo[20] = "BATMAN_IV";
static struct hlist_head batadv_algo_list;

unsigned char batadv_broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

struct workqueue_struct *batadv_event_workqueue;

static void batadv_recv_handler_init(void);

static int __init batadv_init(void)
{
        INIT_LIST_HEAD(&batadv_hardif_list);
        INIT_HLIST_HEAD(&batadv_algo_list);

        batadv_recv_handler_init();

        batadv_v_init();
        batadv_iv_init();
        batadv_nc_init();

        batadv_event_workqueue = create_singlethread_workqueue("bat_events");

        if (!batadv_event_workqueue)
                return -ENOMEM;

        batadv_socket_init();
        batadv_debugfs_init();

        register_netdevice_notifier(&batadv_hard_if_notifier);
        rtnl_link_register(&batadv_link_ops);

        pr_info("B.A.T.M.A.N. advanced %s (compatibility version %i) loaded\n",
                BATADV_SOURCE_VERSION, BATADV_COMPAT_VERSION);

        return 0;
}

static void __exit batadv_exit(void)
{
        batadv_debugfs_destroy();
        rtnl_link_unregister(&batadv_link_ops);
        unregister_netdevice_notifier(&batadv_hard_if_notifier);
        batadv_hardif_remove_interfaces();

        flush_workqueue(batadv_event_workqueue);
        destroy_workqueue(batadv_event_workqueue);
        batadv_event_workqueue = NULL;

        rcu_barrier();
}

int batadv_mesh_init(struct net_device *soft_iface)
{
        struct batadv_priv *bat_priv = netdev_priv(soft_iface);
        int ret;

        spin_lock_init(&bat_priv->forw_bat_list_lock);
        spin_lock_init(&bat_priv->forw_bcast_list_lock);
        spin_lock_init(&bat_priv->tt.changes_list_lock);
        spin_lock_init(&bat_priv->tt.req_list_lock);
        spin_lock_init(&bat_priv->tt.roam_list_lock);
        spin_lock_init(&bat_priv->tt.last_changeset_lock);
        spin_lock_init(&bat_priv->tt.commit_lock);
        spin_lock_init(&bat_priv->gw.list_lock);
#ifdef CONFIG_BATMAN_ADV_MCAST
        spin_lock_init(&bat_priv->mcast.want_lists_lock);
#endif
        spin_lock_init(&bat_priv->tvlv.container_list_lock);
        spin_lock_init(&bat_priv->tvlv.handler_list_lock);
        spin_lock_init(&bat_priv->softif_vlan_list_lock);

        INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
        INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
        INIT_HLIST_HEAD(&bat_priv->gw.list);
#ifdef CONFIG_BATMAN_ADV_MCAST
        INIT_HLIST_HEAD(&bat_priv->mcast.want_all_unsnoopables_list);
        INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv4_list);
        INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv6_list);
#endif
        INIT_LIST_HEAD(&bat_priv->tt.changes_list);
        INIT_HLIST_HEAD(&bat_priv->tt.req_list);
        INIT_LIST_HEAD(&bat_priv->tt.roam_list);
#ifdef CONFIG_BATMAN_ADV_MCAST
        INIT_HLIST_HEAD(&bat_priv->mcast.mla_list);
#endif
        INIT_HLIST_HEAD(&bat_priv->tvlv.container_list);
        INIT_HLIST_HEAD(&bat_priv->tvlv.handler_list);
        INIT_HLIST_HEAD(&bat_priv->softif_vlan_list);

        ret = batadv_v_mesh_init(bat_priv);
        if (ret < 0)
                goto err;

        ret = batadv_originator_init(bat_priv);
        if (ret < 0)
                goto err;

        ret = batadv_tt_init(bat_priv);
        if (ret < 0)
                goto err;

        ret = batadv_bla_init(bat_priv);
        if (ret < 0)
                goto err;

        ret = batadv_dat_init(bat_priv);
        if (ret < 0)
                goto err;

        ret = batadv_nc_mesh_init(bat_priv);
        if (ret < 0)
                goto err;

        batadv_gw_init(bat_priv);
        batadv_mcast_init(bat_priv);

        atomic_set(&bat_priv->gw.reselect, 0);
        atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);

        return 0;

err:
        batadv_mesh_free(soft_iface);
        return ret;
}

void batadv_mesh_free(struct net_device *soft_iface)
{
        struct batadv_priv *bat_priv = netdev_priv(soft_iface);

        atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);

        batadv_purge_outstanding_packets(bat_priv, NULL);

        batadv_gw_node_free(bat_priv);

        batadv_v_mesh_free(bat_priv);
        batadv_nc_mesh_free(bat_priv);
        batadv_dat_free(bat_priv);
        batadv_bla_free(bat_priv);

        batadv_mcast_free(bat_priv);

        /* Free the TT and the originator tables only after having terminated
         * all the other depending components which may use these structures for
         * their purposes.
         */
        batadv_tt_free(bat_priv);

        /* Since the originator table clean up routine is accessing the TT
         * tables as well, it has to be invoked after the TT tables have been
         * freed and marked as empty. This ensures that no cleanup RCU callbacks
         * accessing the TT data are scheduled for later execution.
         */
        batadv_originator_free(bat_priv);

        batadv_gw_free(bat_priv);

        free_percpu(bat_priv->bat_counters);
        bat_priv->bat_counters = NULL;

        atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
}

/**
 * batadv_is_my_mac - check if the given mac address belongs to any of the real
 * interfaces in the current mesh
 * @bat_priv: the bat priv with all the soft interface information
 * @addr: the address to check
 *
 * Return: 'true' if the mac address was found, false otherwise.
 */
bool batadv_is_my_mac(struct batadv_priv *bat_priv, const u8 *addr)
{
        const struct batadv_hard_iface *hard_iface;
        bool is_my_mac = false;

        rcu_read_lock();
        list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
                if (hard_iface->if_status != BATADV_IF_ACTIVE)
                        continue;

                if (hard_iface->soft_iface != bat_priv->soft_iface)
                        continue;

                if (batadv_compare_eth(hard_iface->net_dev->dev_addr, addr)) {
                        is_my_mac = true;
                        break;
                }
        }
        rcu_read_unlock();
        return is_my_mac;
}

/**
 * batadv_seq_print_text_primary_if_get - called from debugfs table printing
 *  function that requires the primary interface
 * @seq: debugfs table seq_file struct
 *
 * Return: primary interface if found or NULL otherwise.
 */
struct batadv_hard_iface *
batadv_seq_print_text_primary_if_get(struct seq_file *seq)
{
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct batadv_priv *bat_priv = netdev_priv(net_dev);
        struct batadv_hard_iface *primary_if;

        primary_if = batadv_primary_if_get_selected(bat_priv);

        if (!primary_if) {
                seq_printf(seq,
                           "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
                           net_dev->name);
                goto out;
        }

        if (primary_if->if_status == BATADV_IF_ACTIVE)
                goto out;

        seq_printf(seq,
                   "BATMAN mesh %s disabled - primary interface not active\n",
                   net_dev->name);
        batadv_hardif_put(primary_if);
        primary_if = NULL;

out:
        return primary_if;
}

/**
 * batadv_max_header_len - calculate maximum encapsulation overhead for a
 *  payload packet
 *
 * Return: the maximum encapsulation overhead in bytes.
 */
int batadv_max_header_len(void)
{
        int header_len = 0;

        header_len = max_t(int, header_len,
                           sizeof(struct batadv_unicast_packet));
        header_len = max_t(int, header_len,
                           sizeof(struct batadv_unicast_4addr_packet));
        header_len = max_t(int, header_len,
                           sizeof(struct batadv_bcast_packet));

#ifdef CONFIG_BATMAN_ADV_NC
        header_len = max_t(int, header_len,
                           sizeof(struct batadv_coded_packet));
#endif

        return header_len + ETH_HLEN;
}

/**
 * batadv_skb_set_priority - sets skb priority according to packet content
 * @skb: the packet to be sent
 * @offset: offset to the packet content
 *
 * This function sets a value between 256 and 263 (802.1d priority), which
 * can be interpreted by the cfg80211 or other drivers.
 */
void batadv_skb_set_priority(struct sk_buff *skb, int offset)
{
        struct iphdr ip_hdr_tmp, *ip_hdr;
        struct ipv6hdr ip6_hdr_tmp, *ip6_hdr;
        struct ethhdr ethhdr_tmp, *ethhdr;
        struct vlan_ethhdr *vhdr, vhdr_tmp;
        u32 prio;

        /* already set, do nothing */
        if (skb->priority >= 256 && skb->priority <= 263)
                return;

        ethhdr = skb_header_pointer(skb, offset, sizeof(*ethhdr), &ethhdr_tmp);
        if (!ethhdr)
                return;

        switch (ethhdr->h_proto) {
        case htons(ETH_P_8021Q):
                vhdr = skb_header_pointer(skb, offset + sizeof(*vhdr),
                                          sizeof(*vhdr), &vhdr_tmp);
                if (!vhdr)
                        return;
                prio = ntohs(vhdr->h_vlan_TCI) & VLAN_PRIO_MASK;
                prio = prio >> VLAN_PRIO_SHIFT;
                break;
        case htons(ETH_P_IP):
                ip_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
                                            sizeof(*ip_hdr), &ip_hdr_tmp);
                if (!ip_hdr)
                        return;
                prio = (ipv4_get_dsfield(ip_hdr) & 0xfc) >> 5;
                break;
        case htons(ETH_P_IPV6):
                ip6_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
                                             sizeof(*ip6_hdr), &ip6_hdr_tmp);
                if (!ip6_hdr)
                        return;
                prio = (ipv6_get_dsfield(ip6_hdr) & 0xfc) >> 5;
                break;
        default:
                return;
        }

        skb->priority = prio + 256;
}

static int batadv_recv_unhandled_packet(struct sk_buff *skb,
                                        struct batadv_hard_iface *recv_if)
{
        return NET_RX_DROP;
}

/* incoming packets with the batman ethertype received on any active hard
 * interface
 */
int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
                           struct packet_type *ptype,
                           struct net_device *orig_dev)
{
        struct batadv_priv *bat_priv;
        struct batadv_ogm_packet *batadv_ogm_packet;
        struct batadv_hard_iface *hard_iface;
        u8 idx;
        int ret;

        hard_iface = container_of(ptype, struct batadv_hard_iface,
                                  batman_adv_ptype);
        skb = skb_share_check(skb, GFP_ATOMIC);

        /* skb was released by skb_share_check() */
        if (!skb)
                goto err_out;

        /* packet should hold at least type and version */
        if (unlikely(!pskb_may_pull(skb, 2)))
                goto err_free;

        /* expect a valid ethernet header here. */
        if (unlikely(skb->mac_len != ETH_HLEN || !skb_mac_header(skb)))
                goto err_free;

        if (!hard_iface->soft_iface)
                goto err_free;

        bat_priv = netdev_priv(hard_iface->soft_iface);

        if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
                goto err_free;

        /* discard frames on not active interfaces */
        if (hard_iface->if_status != BATADV_IF_ACTIVE)
                goto err_free;

        batadv_ogm_packet = (struct batadv_ogm_packet *)skb->data;

        if (batadv_ogm_packet->version != BATADV_COMPAT_VERSION) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: incompatible batman version (%i)\n",
                           batadv_ogm_packet->version);
                goto err_free;
        }

        /* reset control block to avoid left overs from previous users */
        memset(skb->cb, 0, sizeof(struct batadv_skb_cb));

        /* all receive handlers return whether they received or reused
         * the supplied skb. if not, we have to free the skb.
         */
        idx = batadv_ogm_packet->packet_type;
        ret = (*batadv_rx_handler[idx])(skb, hard_iface);

        if (ret == NET_RX_DROP)
                kfree_skb(skb);

        /* return NET_RX_SUCCESS in any case as we
         * most probably dropped the packet for
         * routing-logical reasons.
         */
        return NET_RX_SUCCESS;

err_free:
        kfree_skb(skb);
err_out:
        return NET_RX_DROP;
}

static void batadv_recv_handler_init(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(batadv_rx_handler); i++)
                batadv_rx_handler[i] = batadv_recv_unhandled_packet;

        for (i = BATADV_UNICAST_MIN; i <= BATADV_UNICAST_MAX; i++)
                batadv_rx_handler[i] = batadv_recv_unhandled_unicast_packet;

        /* compile time checks for sizes */
        BUILD_BUG_ON(sizeof(struct batadv_bla_claim_dst) != 6);
        BUILD_BUG_ON(sizeof(struct batadv_ogm_packet) != 24);
        BUILD_BUG_ON(sizeof(struct batadv_icmp_header) != 20);
        BUILD_BUG_ON(sizeof(struct batadv_icmp_packet) != 20);
        BUILD_BUG_ON(sizeof(struct batadv_icmp_packet_rr) != 116);
        BUILD_BUG_ON(sizeof(struct batadv_unicast_packet) != 10);
        BUILD_BUG_ON(sizeof(struct batadv_unicast_4addr_packet) != 18);
        BUILD_BUG_ON(sizeof(struct batadv_frag_packet) != 20);
        BUILD_BUG_ON(sizeof(struct batadv_bcast_packet) != 14);
        BUILD_BUG_ON(sizeof(struct batadv_coded_packet) != 46);
        BUILD_BUG_ON(sizeof(struct batadv_unicast_tvlv_packet) != 20);
        BUILD_BUG_ON(sizeof(struct batadv_tvlv_hdr) != 4);
        BUILD_BUG_ON(sizeof(struct batadv_tvlv_gateway_data) != 8);
        BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_vlan_data) != 8);
        BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_change) != 12);
        BUILD_BUG_ON(sizeof(struct batadv_tvlv_roam_adv) != 8);

        /* broadcast packet */
        batadv_rx_handler[BATADV_BCAST] = batadv_recv_bcast_packet;

        /* unicast packets ... */
        /* unicast with 4 addresses packet */
        batadv_rx_handler[BATADV_UNICAST_4ADDR] = batadv_recv_unicast_packet;
        /* unicast packet */
        batadv_rx_handler[BATADV_UNICAST] = batadv_recv_unicast_packet;
        /* unicast tvlv packet */
        batadv_rx_handler[BATADV_UNICAST_TVLV] = batadv_recv_unicast_tvlv;
        /* batman icmp packet */
        batadv_rx_handler[BATADV_ICMP] = batadv_recv_icmp_packet;
        /* Fragmented packets */
        batadv_rx_handler[BATADV_UNICAST_FRAG] = batadv_recv_frag_packet;
}

int
batadv_recv_handler_register(u8 packet_type,
                             int (*recv_handler)(struct sk_buff *,
                                                 struct batadv_hard_iface *))
{
        int (*curr)(struct sk_buff *,
                    struct batadv_hard_iface *);
        curr = batadv_rx_handler[packet_type];

        if ((curr != batadv_recv_unhandled_packet) &&
            (curr != batadv_recv_unhandled_unicast_packet))
                return -EBUSY;

        batadv_rx_handler[packet_type] = recv_handler;
        return 0;
}

void batadv_recv_handler_unregister(u8 packet_type)
{
        batadv_rx_handler[packet_type] = batadv_recv_unhandled_packet;
}

static struct batadv_algo_ops *batadv_algo_get(char *name)
{
        struct batadv_algo_ops *bat_algo_ops = NULL, *bat_algo_ops_tmp;

        hlist_for_each_entry(bat_algo_ops_tmp, &batadv_algo_list, list) {
                if (strcmp(bat_algo_ops_tmp->name, name) != 0)
                        continue;

                bat_algo_ops = bat_algo_ops_tmp;
                break;
        }

        return bat_algo_ops;
}

int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops)
{
        struct batadv_algo_ops *bat_algo_ops_tmp;

        bat_algo_ops_tmp = batadv_algo_get(bat_algo_ops->name);
        if (bat_algo_ops_tmp) {
                pr_info("Trying to register already registered routing algorithm: %s\n",
                        bat_algo_ops->name);
                return -EEXIST;
        }

        /* all algorithms must implement all ops (for now) */
        if (!bat_algo_ops->bat_iface_enable ||
            !bat_algo_ops->bat_iface_disable ||
            !bat_algo_ops->bat_iface_update_mac ||
            !bat_algo_ops->bat_primary_iface_set ||
            !bat_algo_ops->bat_ogm_schedule ||
            !bat_algo_ops->bat_ogm_emit ||
            !bat_algo_ops->bat_neigh_cmp ||
            !bat_algo_ops->bat_neigh_is_similar_or_better) {
                pr_info("Routing algo '%s' does not implement required ops\n",
                        bat_algo_ops->name);
                return -EINVAL;
        }

        INIT_HLIST_NODE(&bat_algo_ops->list);
        hlist_add_head(&bat_algo_ops->list, &batadv_algo_list);

        return 0;
}

int batadv_algo_select(struct batadv_priv *bat_priv, char *name)
{
        struct batadv_algo_ops *bat_algo_ops;

        bat_algo_ops = batadv_algo_get(name);
        if (!bat_algo_ops)
                return -EINVAL;

        bat_priv->bat_algo_ops = bat_algo_ops;

        return 0;
}

int batadv_algo_seq_print_text(struct seq_file *seq, void *offset)
{
        struct batadv_algo_ops *bat_algo_ops;

        seq_puts(seq, "Available routing algorithms:\n");

        hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
                seq_printf(seq, " * %s\n", bat_algo_ops->name);
        }

        return 0;
}

/**
 * batadv_skb_crc32 - calculate CRC32 of the whole packet and skip bytes in
 *  the header
 * @skb: skb pointing to fragmented socket buffers
 * @payload_ptr: Pointer to position inside the head buffer of the skb
 *  marking the start of the data to be CRC'ed
 *
 * payload_ptr must always point to an address in the skb head buffer and not to
 * a fragment.
 *
 * Return: big endian crc32c of the checksummed data
 */
__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr)
{
        u32 crc = 0;
        unsigned int from;
        unsigned int to = skb->len;
        struct skb_seq_state st;
        const u8 *data;
        unsigned int len;
        unsigned int consumed = 0;

        from = (unsigned int)(payload_ptr - skb->data);

        skb_prepare_seq_read(skb, from, to, &st);
        while ((len = skb_seq_read(consumed, &data, &st)) != 0) {
                crc = crc32c(crc, data, len);
                consumed += len;
        }

        return htonl(crc);
}

/**
 * batadv_tvlv_handler_release - release tvlv handler from lists and queue for
 *  free after rcu grace period
 * @ref: kref pointer of the tvlv
 */
static void batadv_tvlv_handler_release(struct kref *ref)
{
        struct batadv_tvlv_handler *tvlv_handler;

        tvlv_handler = container_of(ref, struct batadv_tvlv_handler, refcount);
        kfree_rcu(tvlv_handler, rcu);
}

/**
 * batadv_tvlv_handler_put - decrement the tvlv container refcounter and
 *  possibly release it
 * @tvlv_handler: the tvlv handler to free
 */
static void batadv_tvlv_handler_put(struct batadv_tvlv_handler *tvlv_handler)
{
        kref_put(&tvlv_handler->refcount, batadv_tvlv_handler_release);
}

/**
 * batadv_tvlv_handler_get - retrieve tvlv handler from the tvlv handler list
 *  based on the provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv handler type to look for
 * @version: tvlv handler version to look for
 *
 * Return: tvlv handler if found or NULL otherwise.
 */
static struct batadv_tvlv_handler
*batadv_tvlv_handler_get(struct batadv_priv *bat_priv, u8 type, u8 version)
{
        struct batadv_tvlv_handler *tvlv_handler_tmp, *tvlv_handler = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tvlv_handler_tmp,
                                 &bat_priv->tvlv.handler_list, list) {
                if (tvlv_handler_tmp->type != type)
                        continue;

                if (tvlv_handler_tmp->version != version)
                        continue;

                if (!kref_get_unless_zero(&tvlv_handler_tmp->refcount))
                        continue;

                tvlv_handler = tvlv_handler_tmp;
                break;
        }
        rcu_read_unlock();

        return tvlv_handler;
}

/**
 * batadv_tvlv_container_release - release tvlv from lists and free
 * @ref: kref pointer of the tvlv
 */
static void batadv_tvlv_container_release(struct kref *ref)
{
        struct batadv_tvlv_container *tvlv;

        tvlv = container_of(ref, struct batadv_tvlv_container, refcount);
        kfree(tvlv);
}

/**
 * batadv_tvlv_container_put - decrement the tvlv container refcounter and
 *  possibly release it
 * @tvlv: the tvlv container to free
 */
static void batadv_tvlv_container_put(struct batadv_tvlv_container *tvlv)
{
        kref_put(&tvlv->refcount, batadv_tvlv_container_release);
}

/**
 * batadv_tvlv_container_get - retrieve tvlv container from the tvlv container
 *  list based on the provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type to look for
 * @version: tvlv container version to look for
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 *
 * Return: tvlv container if found or NULL otherwise.
 */
static struct batadv_tvlv_container
*batadv_tvlv_container_get(struct batadv_priv *bat_priv, u8 type, u8 version)
{
        struct batadv_tvlv_container *tvlv_tmp, *tvlv = NULL;

        lockdep_assert_held(&bat_priv->tvlv.container_list_lock);

        hlist_for_each_entry(tvlv_tmp, &bat_priv->tvlv.container_list, list) {
                if (tvlv_tmp->tvlv_hdr.type != type)
                        continue;

                if (tvlv_tmp->tvlv_hdr.version != version)
                        continue;

                if (!kref_get_unless_zero(&tvlv_tmp->refcount))
                        continue;

                tvlv = tvlv_tmp;
                break;
        }

        return tvlv;
}

/**
 * batadv_tvlv_container_list_size - calculate the size of the tvlv container
 *  list entries
 * @bat_priv: the bat priv with all the soft interface information
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 *
 * Return: size of all currently registered tvlv containers in bytes.
 */
static u16 batadv_tvlv_container_list_size(struct batadv_priv *bat_priv)
{
        struct batadv_tvlv_container *tvlv;
        u16 tvlv_len = 0;

        lockdep_assert_held(&bat_priv->tvlv.container_list_lock);

        hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
                tvlv_len += sizeof(struct batadv_tvlv_hdr);
                tvlv_len += ntohs(tvlv->tvlv_hdr.len);
        }

        return tvlv_len;
}

/**
 * batadv_tvlv_container_remove - remove tvlv container from the tvlv container
 *  list
 * @bat_priv: the bat priv with all the soft interface information
 * @tvlv: the to be removed tvlv container
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 */
static void batadv_tvlv_container_remove(struct batadv_priv *bat_priv,
                                         struct batadv_tvlv_container *tvlv)
{
        lockdep_assert_held(&bat_priv->tvlv.container_list_lock);

        if (!tvlv)
                return;

        hlist_del(&tvlv->list);

        /* first call to decrement the counter, second call to free */
        batadv_tvlv_container_put(tvlv);
        batadv_tvlv_container_put(tvlv);
}

/**
 * batadv_tvlv_container_unregister - unregister tvlv container based on the
 *  provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type to unregister
 * @version: tvlv container type to unregister
 */
void batadv_tvlv_container_unregister(struct batadv_priv *bat_priv,
                                      u8 type, u8 version)
{
        struct batadv_tvlv_container *tvlv;

        spin_lock_bh(&bat_priv->tvlv.container_list_lock);
        tvlv = batadv_tvlv_container_get(bat_priv, type, version);
        batadv_tvlv_container_remove(bat_priv, tvlv);
        spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
}

/**
 * batadv_tvlv_container_register - register tvlv type, version and content
 *  to be propagated with each (primary interface) OGM
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type
 * @version: tvlv container version
 * @tvlv_value: tvlv container content
 * @tvlv_value_len: tvlv container content length
 *
 * If a container of the same type and version was already registered the new
 * content is going to replace the old one.
 */
void batadv_tvlv_container_register(struct batadv_priv *bat_priv,
                                    u8 type, u8 version,
                                    void *tvlv_value, u16 tvlv_value_len)
{
        struct batadv_tvlv_container *tvlv_old, *tvlv_new;

        if (!tvlv_value)
                tvlv_value_len = 0;

        tvlv_new = kzalloc(sizeof(*tvlv_new) + tvlv_value_len, GFP_ATOMIC);
        if (!tvlv_new)
                return;

        tvlv_new->tvlv_hdr.version = version;
        tvlv_new->tvlv_hdr.type = type;
        tvlv_new->tvlv_hdr.len = htons(tvlv_value_len);

        memcpy(tvlv_new + 1, tvlv_value, ntohs(tvlv_new->tvlv_hdr.len));
        INIT_HLIST_NODE(&tvlv_new->list);
        kref_init(&tvlv_new->refcount);

        spin_lock_bh(&bat_priv->tvlv.container_list_lock);
        tvlv_old = batadv_tvlv_container_get(bat_priv, type, version);
        batadv_tvlv_container_remove(bat_priv, tvlv_old);
        hlist_add_head(&tvlv_new->list, &bat_priv->tvlv.container_list);
        spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
}

/**
 * batadv_tvlv_realloc_packet_buff - reallocate packet buffer to accommodate
 *  requested packet size
 * @packet_buff: packet buffer
 * @packet_buff_len: packet buffer size
 * @min_packet_len: requested packet minimum size
 * @additional_packet_len: requested additional packet size on top of minimum
 *  size
 *
 * Return: true of the packet buffer could be changed to the requested size,
 * false otherwise.
 */
static bool batadv_tvlv_realloc_packet_buff(unsigned char **packet_buff,
                                            int *packet_buff_len,
                                            int min_packet_len,
                                            int additional_packet_len)
{
        unsigned char *new_buff;

        new_buff = kmalloc(min_packet_len + additional_packet_len, GFP_ATOMIC);

        /* keep old buffer if kmalloc should fail */
        if (!new_buff)
                return false;

        memcpy(new_buff, *packet_buff, min_packet_len);
        kfree(*packet_buff);
        *packet_buff = new_buff;
        *packet_buff_len = min_packet_len + additional_packet_len;

        return true;
}

/**
 * batadv_tvlv_container_ogm_append - append tvlv container content to given
 *  OGM packet buffer
 * @bat_priv: the bat priv with all the soft interface information
 * @packet_buff: ogm packet buffer
 * @packet_buff_len: ogm packet buffer size including ogm header and tvlv
 *  content
 * @packet_min_len: ogm header size to be preserved for the OGM itself
 *
 * The ogm packet might be enlarged or shrunk depending on the current size
 * and the size of the to-be-appended tvlv containers.
 *
 * Return: size of all appended tvlv containers in bytes.
 */
u16 batadv_tvlv_container_ogm_append(struct batadv_priv *bat_priv,
                                     unsigned char **packet_buff,
                                     int *packet_buff_len, int packet_min_len)
{
        struct batadv_tvlv_container *tvlv;
        struct batadv_tvlv_hdr *tvlv_hdr;
        u16 tvlv_value_len;
        void *tvlv_value;
        bool ret;

        spin_lock_bh(&bat_priv->tvlv.container_list_lock);
        tvlv_value_len = batadv_tvlv_container_list_size(bat_priv);

        ret = batadv_tvlv_realloc_packet_buff(packet_buff, packet_buff_len,
                                              packet_min_len, tvlv_value_len);

        if (!ret)
                goto end;

        if (!tvlv_value_len)
                goto end;

        tvlv_value = (*packet_buff) + packet_min_len;

        hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
                tvlv_hdr = tvlv_value;
                tvlv_hdr->type = tvlv->tvlv_hdr.type;
                tvlv_hdr->version = tvlv->tvlv_hdr.version;
                tvlv_hdr->len = tvlv->tvlv_hdr.len;
                tvlv_value = tvlv_hdr + 1;
                memcpy(tvlv_value, tvlv + 1, ntohs(tvlv->tvlv_hdr.len));
                tvlv_value = (u8 *)tvlv_value + ntohs(tvlv->tvlv_hdr.len);
        }

end:
        spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
        return tvlv_value_len;
}

/**
 * batadv_tvlv_call_handler - parse the given tvlv buffer to call the
 *  appropriate handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @tvlv_handler: tvlv callback function handling the tvlv content
 * @ogm_source: flag indicating whether the tvlv is an ogm or a unicast packet
 * @orig_node: orig node emitting the ogm packet
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 *
 * Return: success if handler was not found or the return value of the handler
 * callback.
 */
static int batadv_tvlv_call_handler(struct batadv_priv *bat_priv,
                                    struct batadv_tvlv_handler *tvlv_handler,
                                    bool ogm_source,
                                    struct batadv_orig_node *orig_node,
                                    u8 *src, u8 *dst,
                                    void *tvlv_value, u16 tvlv_value_len)
{
        if (!tvlv_handler)
                return NET_RX_SUCCESS;

        if (ogm_source) {
                if (!tvlv_handler->ogm_handler)
                        return NET_RX_SUCCESS;

                if (!orig_node)
                        return NET_RX_SUCCESS;

                tvlv_handler->ogm_handler(bat_priv, orig_node,
                                          BATADV_NO_FLAGS,
                                          tvlv_value, tvlv_value_len);
                tvlv_handler->flags |= BATADV_TVLV_HANDLER_OGM_CALLED;
        } else {
                if (!src)
                        return NET_RX_SUCCESS;

                if (!dst)
                        return NET_RX_SUCCESS;

                if (!tvlv_handler->unicast_handler)
                        return NET_RX_SUCCESS;

                return tvlv_handler->unicast_handler(bat_priv, src,
                                                     dst, tvlv_value,
                                                     tvlv_value_len);
        }

        return NET_RX_SUCCESS;
}

/**
 * batadv_tvlv_containers_process - parse the given tvlv buffer to call the
 *  appropriate handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @ogm_source: flag indicating whether the tvlv is an ogm or a unicast packet

 * @orig_node: orig node emitting the ogm packet
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 *
 * Return: success when processing an OGM or the return value of all called
 * handler callbacks.
 */
int batadv_tvlv_containers_process(struct batadv_priv *bat_priv,
                                   bool ogm_source,
                                   struct batadv_orig_node *orig_node,
                                   u8 *src, u8 *dst,
                                   void *tvlv_value, u16 tvlv_value_len)
{
        struct batadv_tvlv_handler *tvlv_handler;
        struct batadv_tvlv_hdr *tvlv_hdr;
        u16 tvlv_value_cont_len;
        u8 cifnotfound = BATADV_TVLV_HANDLER_OGM_CIFNOTFND;
        int ret = NET_RX_SUCCESS;

        while (tvlv_value_len >= sizeof(*tvlv_hdr)) {
                tvlv_hdr = tvlv_value;
                tvlv_value_cont_len = ntohs(tvlv_hdr->len);
                tvlv_value = tvlv_hdr + 1;
                tvlv_value_len -= sizeof(*tvlv_hdr);

                if (tvlv_value_cont_len > tvlv_value_len)
                        break;

                tvlv_handler = batadv_tvlv_handler_get(bat_priv,
                                                       tvlv_hdr->type,
                                                       tvlv_hdr->version);

                ret |= batadv_tvlv_call_handler(bat_priv, tvlv_handler,
                                                ogm_source, orig_node,
                                                src, dst, tvlv_value,
                                                tvlv_value_cont_len);
                if (tvlv_handler)
                        batadv_tvlv_handler_put(tvlv_handler);
                tvlv_value = (u8 *)tvlv_value + tvlv_value_cont_len;
                tvlv_value_len -= tvlv_value_cont_len;
        }

        if (!ogm_source)
                return ret;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tvlv_handler,
                                 &bat_priv->tvlv.handler_list, list) {
                if ((tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) &&
                    !(tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CALLED))
                        tvlv_handler->ogm_handler(bat_priv, orig_node,
                                                  cifnotfound, NULL, 0);

                tvlv_handler->flags &= ~BATADV_TVLV_HANDLER_OGM_CALLED;
        }
        rcu_read_unlock();

        return NET_RX_SUCCESS;
}

/**
 * batadv_tvlv_ogm_receive - process an incoming ogm and call the appropriate
 *  handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @batadv_ogm_packet: ogm packet containing the tvlv containers
 * @orig_node: orig node emitting the ogm packet
 */
void batadv_tvlv_ogm_receive(struct batadv_priv *bat_priv,
                             struct batadv_ogm_packet *batadv_ogm_packet,
                             struct batadv_orig_node *orig_node)
{
        void *tvlv_value;
        u16 tvlv_value_len;

        if (!batadv_ogm_packet)
                return;

        tvlv_value_len = ntohs(batadv_ogm_packet->tvlv_len);
        if (!tvlv_value_len)
                return;

        tvlv_value = batadv_ogm_packet + 1;

        batadv_tvlv_containers_process(bat_priv, true, orig_node, NULL, NULL,
                                       tvlv_value, tvlv_value_len);
}

/**
 * batadv_tvlv_handler_register - register tvlv handler based on the provided
 *  type and version (both need to match) for ogm tvlv payload and/or unicast
 *  payload
 * @bat_priv: the bat priv with all the soft interface information
 * @optr: ogm tvlv handler callback function. This function receives the orig
 *  node, flags and the tvlv content as argument to process.
 * @uptr: unicast tvlv handler callback function. This function receives the
 *  source & destination of the unicast packet as well as the tvlv content
 *  to process.
 * @type: tvlv handler type to be registered
 * @version: tvlv handler version to be registered
 * @flags: flags to enable or disable TVLV API behavior
 */
void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
                                  void (*optr)(struct batadv_priv *bat_priv,
                                               struct batadv_orig_node *orig,
                                               u8 flags,
                                               void *tvlv_value,
                                               u16 tvlv_value_len),
                                  int (*uptr)(struct batadv_priv *bat_priv,
                                              u8 *src, u8 *dst,
                                              void *tvlv_value,
                                              u16 tvlv_value_len),
                                  u8 type, u8 version, u8 flags)
{
        struct batadv_tvlv_handler *tvlv_handler;

        tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
        if (tvlv_handler) {
                batadv_tvlv_handler_put(tvlv_handler);
                return;
        }

        tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC);
        if (!tvlv_handler)
                return;

        tvlv_handler->ogm_handler = optr;
        tvlv_handler->unicast_handler = uptr;
        tvlv_handler->type = type;
        tvlv_handler->version = version;
        tvlv_handler->flags = flags;
        kref_init(&tvlv_handler->refcount);
        INIT_HLIST_NODE(&tvlv_handler->list);

        spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
        hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list);
        spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
}

/**
 * batadv_tvlv_handler_unregister - unregister tvlv handler based on the
 *  provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv handler type to be unregistered
 * @version: tvlv handler version to be unregistered
 */
void batadv_tvlv_handler_unregister(struct batadv_priv *bat_priv,
                                    u8 type, u8 version)
{
        struct batadv_tvlv_handler *tvlv_handler;

        tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
        if (!tvlv_handler)
                return;

        batadv_tvlv_handler_put(tvlv_handler);
        spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
        hlist_del_rcu(&tvlv_handler->list);
        spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
        batadv_tvlv_handler_put(tvlv_handler);
}

/**
 * batadv_tvlv_unicast_send - send a unicast packet with tvlv payload to the
 *  specified host
 * @bat_priv: the bat priv with all the soft interface information
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @type: tvlv type
 * @version: tvlv version
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 */
void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, u8 *src,
                              u8 *dst, u8 type, u8 version,
                              void *tvlv_value, u16 tvlv_value_len)
{
        struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
        struct batadv_tvlv_hdr *tvlv_hdr;
        struct batadv_orig_node *orig_node;
        struct sk_buff *skb;
        unsigned char *tvlv_buff;
        unsigned int tvlv_len;
        ssize_t hdr_len = sizeof(*unicast_tvlv_packet);

        orig_node = batadv_orig_hash_find(bat_priv, dst);
        if (!orig_node)
                return;

        tvlv_len = sizeof(*tvlv_hdr) + tvlv_value_len;

        skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + hdr_len + tvlv_len);
        if (!skb)
                goto out;

        skb->priority = TC_PRIO_CONTROL;
        skb_reserve(skb, ETH_HLEN);
        tvlv_buff = skb_put(skb, sizeof(*unicast_tvlv_packet) + tvlv_len);
        unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)tvlv_buff;
        unicast_tvlv_packet->packet_type = BATADV_UNICAST_TVLV;
        unicast_tvlv_packet->version = BATADV_COMPAT_VERSION;
        unicast_tvlv_packet->ttl = BATADV_TTL;
        unicast_tvlv_packet->reserved = 0;
        unicast_tvlv_packet->tvlv_len = htons(tvlv_len);
        unicast_tvlv_packet->align = 0;
        ether_addr_copy(unicast_tvlv_packet->src, src);
        ether_addr_copy(unicast_tvlv_packet->dst, dst);

        tvlv_buff = (unsigned char *)(unicast_tvlv_packet + 1);
        tvlv_hdr = (struct batadv_tvlv_hdr *)tvlv_buff;
        tvlv_hdr->version = version;
        tvlv_hdr->type = type;
        tvlv_hdr->len = htons(tvlv_value_len);
        tvlv_buff += sizeof(*tvlv_hdr);
        memcpy(tvlv_buff, tvlv_value, tvlv_value_len);

        if (batadv_send_skb_to_orig(skb, orig_node, NULL) == NET_XMIT_DROP)
                kfree_skb(skb);
out:
        batadv_orig_node_put(orig_node);
}

/**
 * batadv_get_vid - extract the VLAN identifier from skb if any
 * @skb: the buffer containing the packet
 * @header_len: length of the batman header preceding the ethernet header
 *
 * Return: VID with the BATADV_VLAN_HAS_TAG flag when the packet embedded in the
 * skb is vlan tagged. Otherwise BATADV_NO_FLAGS.
 */
unsigned short batadv_get_vid(struct sk_buff *skb, size_t header_len)
{
        struct ethhdr *ethhdr = (struct ethhdr *)(skb->data + header_len);
        struct vlan_ethhdr *vhdr;
        unsigned short vid;

        if (ethhdr->h_proto != htons(ETH_P_8021Q))
                return BATADV_NO_FLAGS;

        if (!pskb_may_pull(skb, header_len + VLAN_ETH_HLEN))
                return BATADV_NO_FLAGS;

        vhdr = (struct vlan_ethhdr *)(skb->data + header_len);
        vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
        vid |= BATADV_VLAN_HAS_TAG;

        return vid;
}

/**
 * batadv_vlan_ap_isola_get - return the AP isolation status for the given vlan
 * @bat_priv: the bat priv with all the soft interface information
 * @vid: the VLAN identifier for which the AP isolation attributed as to be
 *  looked up
 *
 * Return: true if AP isolation is on for the VLAN idenfied by vid, false
 * otherwise
 */
bool batadv_vlan_ap_isola_get(struct batadv_priv *bat_priv, unsigned short vid)
{
        bool ap_isolation_enabled = false;
        struct batadv_softif_vlan *vlan;

        /* if the AP isolation is requested on a VLAN, then check for its
         * setting in the proper VLAN private data structure
         */
        vlan = batadv_softif_vlan_get(bat_priv, vid);
        if (vlan) {
                ap_isolation_enabled = atomic_read(&vlan->ap_isolation);
                batadv_softif_vlan_put(vlan);
        }

        return ap_isolation_enabled;
}

static int batadv_param_set_ra(const char *val, const struct kernel_param *kp)
{
        struct batadv_algo_ops *bat_algo_ops;
        char *algo_name = (char *)val;
        size_t name_len = strlen(algo_name);

        if (name_len > 0 && algo_name[name_len - 1] == '\n')
                algo_name[name_len - 1] = '\0';

        bat_algo_ops = batadv_algo_get(algo_name);
        if (!bat_algo_ops) {
                pr_err("Routing algorithm '%s' is not supported\n", algo_name);
                return -EINVAL;
        }

        return param_set_copystring(algo_name, kp);
}

static const struct kernel_param_ops batadv_param_ops_ra = {
        .set = batadv_param_set_ra,
        .get = param_get_string,
};

static struct kparam_string batadv_param_string_ra = {
        .maxlen = sizeof(batadv_routing_algo),
        .string = batadv_routing_algo,
};

module_param_cb(routing_algo, &batadv_param_ops_ra, &batadv_param_string_ra,
                0644);
module_init(batadv_init);
module_exit(batadv_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR(BATADV_DRIVER_AUTHOR);
MODULE_DESCRIPTION(BATADV_DRIVER_DESC);
MODULE_SUPPORTED_DEVICE(BATADV_DRIVER_DEVICE);
MODULE_VERSION(BATADV_SOURCE_VERSION);