/* Copyright (C) 2007-2012 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#include "main.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "routing.h"
#include "send.h"
#include "debugfs.h"
#include "translation-table.h"
#include "hash.h"
#include "gateway_common.h"
#include "gateway_client.h"
#include "sysfs.h"
#include "originator.h"
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include "unicast.h"
#include "bridge_loop_avoidance.h"


static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd);
static void batadv_get_drvinfo(struct net_device *dev,
                               struct ethtool_drvinfo *info);
static u32 batadv_get_msglevel(struct net_device *dev);
static void batadv_set_msglevel(struct net_device *dev, u32 value);
static u32 batadv_get_link(struct net_device *dev);
static void batadv_get_strings(struct net_device *dev, u32 stringset, u8 *data);
static void batadv_get_ethtool_stats(struct net_device *dev,
                                     struct ethtool_stats *stats, u64 *data);
static int batadv_get_sset_count(struct net_device *dev, int stringset);

static const struct ethtool_ops batadv_ethtool_ops = {
        .get_settings = batadv_get_settings,
        .get_drvinfo = batadv_get_drvinfo,
        .get_msglevel = batadv_get_msglevel,
        .set_msglevel = batadv_set_msglevel,
        .get_link = batadv_get_link,
        .get_strings = batadv_get_strings,
        .get_ethtool_stats = batadv_get_ethtool_stats,
        .get_sset_count = batadv_get_sset_count,
};

int batadv_skb_head_push(struct sk_buff *skb, unsigned int len)
{
        int result;

        /* TODO: We must check if we can release all references to non-payload
         * data using skb_header_release in our skbs to allow skb_cow_header to
         * work optimally. This means that those skbs are not allowed to read
         * or write any data which is before the current position of skb->data
         * after that call and thus allow other skbs with the same data buffer
         * to write freely in that area.
         */
        result = skb_cow_head(skb, len);
        if (result < 0)
                return result;

        skb_push(skb, len);
        return 0;
}

static int batadv_interface_open(struct net_device *dev)
{
        netif_start_queue(dev);
        return 0;
}

static int batadv_interface_release(struct net_device *dev)
{
        netif_stop_queue(dev);
        return 0;
}

static struct net_device_stats *batadv_interface_stats(struct net_device *dev)
{
        struct batadv_priv *bat_priv = netdev_priv(dev);
        return &bat_priv->stats;
}

static int batadv_interface_set_mac_addr(struct net_device *dev, void *p)
{
        struct batadv_priv *bat_priv = netdev_priv(dev);
        struct sockaddr *addr = p;
        uint8_t old_addr[ETH_ALEN];

        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;

        memcpy(old_addr, dev->dev_addr, ETH_ALEN);
        memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);

        /* only modify transtable if it has been initialized before */
        if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE) {
                batadv_tt_local_remove(bat_priv, old_addr,
                                       "mac address changed", false);
                batadv_tt_local_add(dev, addr->sa_data, BATADV_NULL_IFINDEX);
        }

        dev->addr_assign_type &= ~NET_ADDR_RANDOM;
        return 0;
}

static int batadv_interface_change_mtu(struct net_device *dev, int new_mtu)
{
        /* check ranges */
        if ((new_mtu < 68) || (new_mtu > batadv_hardif_min_mtu(dev)))
                return -EINVAL;

        dev->mtu = new_mtu;

        return 0;
}

static int batadv_interface_tx(struct sk_buff *skb,
                               struct net_device *soft_iface)
{
        struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
        struct batadv_priv *bat_priv = netdev_priv(soft_iface);
        struct batadv_hard_iface *primary_if = NULL;
        struct batadv_bcast_packet *bcast_packet;
        struct vlan_ethhdr *vhdr;
        __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
        static const uint8_t stp_addr[ETH_ALEN] = {0x01, 0x80, 0xC2, 0x00, 0x00,
                                                   0x00};
        unsigned int header_len = 0;
        int data_len = skb->len, ret;
        short vid __maybe_unused = -1;
        bool do_bcast = false;

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

        soft_iface->trans_start = jiffies;

        switch (ntohs(ethhdr->h_proto)) {
        case ETH_P_8021Q:
                vhdr = (struct vlan_ethhdr *)skb->data;
                vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;

                if (vhdr->h_vlan_encapsulated_proto != ethertype)
                        break;

                /* fall through */
        case BATADV_ETH_P_BATMAN:
                goto dropped;
        }

        if (batadv_bla_tx(bat_priv, skb, vid))
                goto dropped;

        /* Register the client MAC in the transtable */
        batadv_tt_local_add(soft_iface, ethhdr->h_source, skb->skb_iif);

        /* don't accept stp packets. STP does not help in meshes.
         * better use the bridge loop avoidance ...
         */
        if (batadv_compare_eth(ethhdr->h_dest, stp_addr))
                goto dropped;

        if (is_multicast_ether_addr(ethhdr->h_dest)) {
                do_bcast = true;

                switch (atomic_read(&bat_priv->gw_mode)) {
                case BATADV_GW_MODE_SERVER:
                        /* gateway servers should not send dhcp
                         * requests into the mesh
                         */
                        ret = batadv_gw_is_dhcp_target(skb, &header_len);
                        if (ret)
                                goto dropped;
                        break;
                case BATADV_GW_MODE_CLIENT:
                        /* gateway clients should send dhcp requests
                         * via unicast to their gateway
                         */
                        ret = batadv_gw_is_dhcp_target(skb, &header_len);
                        if (ret)
                                do_bcast = false;
                        break;
                case BATADV_GW_MODE_OFF:
                default:
                        break;
                }
        }

        /* ethernet packet should be broadcasted */
        if (do_bcast) {
                primary_if = batadv_primary_if_get_selected(bat_priv);
                if (!primary_if)
                        goto dropped;

                if (batadv_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
                        goto dropped;

                bcast_packet = (struct batadv_bcast_packet *)skb->data;
                bcast_packet->header.version = BATADV_COMPAT_VERSION;
                bcast_packet->header.ttl = BATADV_TTL;

                /* batman packet type: broadcast */
                bcast_packet->header.packet_type = BATADV_BCAST;
                bcast_packet->reserved = 0;

                /* hw address of first interface is the orig mac because only
                 * this mac is known throughout the mesh
                 */
                memcpy(bcast_packet->orig,
                       primary_if->net_dev->dev_addr, ETH_ALEN);

                /* set broadcast sequence number */
                bcast_packet->seqno =
                        htonl(atomic_inc_return(&bat_priv->bcast_seqno));

                batadv_add_bcast_packet_to_list(bat_priv, skb, 1);

                /* a copy is stored in the bcast list, therefore removing
                 * the original skb.
                 */
                kfree_skb(skb);

        /* unicast packet */
        } else {
                if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_OFF) {
                        ret = batadv_gw_out_of_range(bat_priv, skb, ethhdr);
                        if (ret)
                                goto dropped;
                }

                ret = batadv_unicast_send_skb(skb, bat_priv);
                if (ret != 0)
                        goto dropped_freed;
        }

        bat_priv->stats.tx_packets++;
        bat_priv->stats.tx_bytes += data_len;
        goto end;

dropped:
        kfree_skb(skb);
dropped_freed:
        bat_priv->stats.tx_dropped++;
end:
        if (primary_if)
                batadv_hardif_free_ref(primary_if);
        return NETDEV_TX_OK;
}

void batadv_interface_rx(struct net_device *soft_iface,
                         struct sk_buff *skb, struct batadv_hard_iface *recv_if,
                         int hdr_size)
{
        struct batadv_priv *bat_priv = netdev_priv(soft_iface);
        struct ethhdr *ethhdr;
        struct vlan_ethhdr *vhdr;
        struct batadv_header *batadv_header = (struct batadv_header *)skb->data;
        short vid __maybe_unused = -1;
        __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
        bool is_bcast;

        is_bcast = (batadv_header->packet_type == BATADV_BCAST);

        /* check if enough space is available for pulling, and pull */
        if (!pskb_may_pull(skb, hdr_size))
                goto dropped;

        skb_pull_rcsum(skb, hdr_size);
        skb_reset_mac_header(skb);

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        switch (ntohs(ethhdr->h_proto)) {
        case ETH_P_8021Q:
                vhdr = (struct vlan_ethhdr *)skb->data;
                vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;

                if (vhdr->h_vlan_encapsulated_proto != ethertype)
                        break;

                /* fall through */
        case BATADV_ETH_P_BATMAN:
                goto dropped;
        }

        /* skb->dev & skb->pkt_type are set here */
        if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
                goto dropped;
        skb->protocol = eth_type_trans(skb, soft_iface);

        /* should not be necessary anymore as we use skb_pull_rcsum()
         * TODO: please verify this and remove this TODO
         * -- Dec 21st 2009, Simon Wunderlich
         */

        /* skb->ip_summed = CHECKSUM_UNNECESSARY; */

        bat_priv->stats.rx_packets++;
        bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;

        soft_iface->last_rx = jiffies;

        if (batadv_is_ap_isolated(bat_priv, ethhdr->h_source, ethhdr->h_dest))
                goto dropped;

        /* Let the bridge loop avoidance check the packet. If will
         * not handle it, we can safely push it up.
         */
        if (batadv_bla_rx(bat_priv, skb, vid, is_bcast))
                goto out;

        netif_rx(skb);
        goto out;

dropped:
        kfree_skb(skb);
out:
        return;
}

static const struct net_device_ops batadv_netdev_ops = {
        .ndo_open = batadv_interface_open,
        .ndo_stop = batadv_interface_release,
        .ndo_get_stats = batadv_interface_stats,
        .ndo_set_mac_address = batadv_interface_set_mac_addr,
        .ndo_change_mtu = batadv_interface_change_mtu,
        .ndo_start_xmit = batadv_interface_tx,
        .ndo_validate_addr = eth_validate_addr
};

static void batadv_interface_setup(struct net_device *dev)
{
        struct batadv_priv *priv = netdev_priv(dev);

        ether_setup(dev);

        dev->netdev_ops = &batadv_netdev_ops;
        dev->destructor = free_netdev;
        dev->tx_queue_len = 0;

        /* can't call min_mtu, because the needed variables
         * have not been initialized yet
         */
        dev->mtu = ETH_DATA_LEN;
        /* reserve more space in the skbuff for our header */
        dev->hard_header_len = BATADV_HEADER_LEN;

        /* generate random address */
        eth_hw_addr_random(dev);

        SET_ETHTOOL_OPS(dev, &batadv_ethtool_ops);

        memset(priv, 0, sizeof(*priv));
}

struct net_device *batadv_softif_create(const char *name)
{
        struct net_device *soft_iface;
        struct batadv_priv *bat_priv;
        int ret;
        size_t cnt_len = sizeof(uint64_t) * BATADV_CNT_NUM;

        soft_iface = alloc_netdev(sizeof(*bat_priv), name,
                                  batadv_interface_setup);

        if (!soft_iface)
                goto out;

        ret = register_netdevice(soft_iface);
        if (ret < 0) {
                pr_err("Unable to register the batman interface '%s': %i\n",
                       name, ret);
                goto free_soft_iface;
        }

        bat_priv = netdev_priv(soft_iface);

        atomic_set(&bat_priv->aggregated_ogms, 1);
        atomic_set(&bat_priv->bonding, 0);
        atomic_set(&bat_priv->bridge_loop_avoidance, 0);
        atomic_set(&bat_priv->ap_isolation, 0);
        atomic_set(&bat_priv->vis_mode, BATADV_VIS_TYPE_CLIENT_UPDATE);
        atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
        atomic_set(&bat_priv->gw_sel_class, 20);
        atomic_set(&bat_priv->gw_bandwidth, 41);
        atomic_set(&bat_priv->orig_interval, 1000);
        atomic_set(&bat_priv->hop_penalty, 30);
        atomic_set(&bat_priv->log_level, 0);
        atomic_set(&bat_priv->fragmentation, 1);
        atomic_set(&bat_priv->bcast_queue_left, BATADV_BCAST_QUEUE_LEN);
        atomic_set(&bat_priv->batman_queue_left, BATADV_BATMAN_QUEUE_LEN);

        atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
        atomic_set(&bat_priv->bcast_seqno, 1);
        atomic_set(&bat_priv->ttvn, 0);
        atomic_set(&bat_priv->tt_local_changes, 0);
        atomic_set(&bat_priv->tt_ogm_append_cnt, 0);
        atomic_set(&bat_priv->bla_num_requests, 0);

        bat_priv->tt_buff = NULL;
        bat_priv->tt_buff_len = 0;
        bat_priv->tt_poss_change = false;

        bat_priv->primary_if = NULL;
        bat_priv->num_ifaces = 0;

        bat_priv->bat_counters = __alloc_percpu(cnt_len, __alignof__(uint64_t));
        if (!bat_priv->bat_counters)
                goto unreg_soft_iface;

        ret = batadv_algo_select(bat_priv, batadv_routing_algo);
        if (ret < 0)
                goto free_bat_counters;

        ret = batadv_sysfs_add_meshif(soft_iface);
        if (ret < 0)
                goto free_bat_counters;

        ret = batadv_debugfs_add_meshif(soft_iface);
        if (ret < 0)
                goto unreg_sysfs;

        ret = batadv_mesh_init(soft_iface);
        if (ret < 0)
                goto unreg_debugfs;

        return soft_iface;

unreg_debugfs:
        batadv_debugfs_del_meshif(soft_iface);
unreg_sysfs:
        batadv_sysfs_del_meshif(soft_iface);
free_bat_counters:
        free_percpu(bat_priv->bat_counters);
unreg_soft_iface:
        unregister_netdevice(soft_iface);
        return NULL;

free_soft_iface:
        free_netdev(soft_iface);
out:
        return NULL;
}

void batadv_softif_destroy(struct net_device *soft_iface)
{
        batadv_debugfs_del_meshif(soft_iface);
        batadv_sysfs_del_meshif(soft_iface);
        batadv_mesh_free(soft_iface);
        unregister_netdevice(soft_iface);
}

int batadv_softif_is_valid(const struct net_device *net_dev)
{
        if (net_dev->netdev_ops->ndo_start_xmit == batadv_interface_tx)
                return 1;

        return 0;
}

/* ethtool */
static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        cmd->supported = 0;
        cmd->advertising = 0;
        ethtool_cmd_speed_set(cmd, SPEED_10);
        cmd->duplex = DUPLEX_FULL;
        cmd->port = PORT_TP;
        cmd->phy_address = 0;
        cmd->transceiver = XCVR_INTERNAL;
        cmd->autoneg = AUTONEG_DISABLE;
        cmd->maxtxpkt = 0;
        cmd->maxrxpkt = 0;

        return 0;
}

static void batadv_get_drvinfo(struct net_device *dev,
                               struct ethtool_drvinfo *info)
{
        strcpy(info->driver, "B.A.T.M.A.N. advanced");
        strcpy(info->version, BATADV_SOURCE_VERSION);
        strcpy(info->fw_version, "N/A");
        strcpy(info->bus_info, "batman");
}

static u32 batadv_get_msglevel(struct net_device *dev)
{
        return -EOPNOTSUPP;
}

static void batadv_set_msglevel(struct net_device *dev, u32 value)
{
}

static u32 batadv_get_link(struct net_device *dev)
{
        return 1;
}

/* Inspired by drivers/net/ethernet/dlink/sundance.c:1702
 * Declare each description string in struct.name[] to get fixed sized buffer
 * and compile time checking for strings longer than ETH_GSTRING_LEN.
 */
static const struct {
        const char name[ETH_GSTRING_LEN];
} batadv_counters_strings[] = {
        { "forward" },
        { "forward_bytes" },
        { "mgmt_tx" },
        { "mgmt_tx_bytes" },
        { "mgmt_rx" },
        { "mgmt_rx_bytes" },
        { "tt_request_tx" },
        { "tt_request_rx" },
        { "tt_response_tx" },
        { "tt_response_rx" },
        { "tt_roam_adv_tx" },
        { "tt_roam_adv_rx" },
};

static void batadv_get_strings(struct net_device *dev, uint32_t stringset,
                               uint8_t *data)
{
        if (stringset == ETH_SS_STATS)
                memcpy(data, batadv_counters_strings,
                       sizeof(batadv_counters_strings));
}

static void batadv_get_ethtool_stats(struct net_device *dev,
                                     struct ethtool_stats *stats,
                                     uint64_t *data)
{
        struct batadv_priv *bat_priv = netdev_priv(dev);
        int i;

        for (i = 0; i < BATADV_CNT_NUM; i++)
                data[i] = batadv_sum_counter(bat_priv, i);
}

static int batadv_get_sset_count(struct net_device *dev, int stringset)
{
        if (stringset == ETH_SS_STATS)
                return BATADV_CNT_NUM;

        return -EOPNOTSUPP;
}