br_device.c

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/*
 *  Device handling code
 *  Linux ethernet bridge
 *
 *  Authors:
 *  Lennert Buytenhek       <[email protected]>
 *
 *  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/netpoll.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/list.h>
#include <linux/netfilter_bridge.h>

#include <asm/uaccess.h>
#include "br_private.h"

/* net device transmit always called with BH disabled */
netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);
    const unsigned char *dest = skb->data;
    struct net_bridge_fdb_entry *dst;
    struct net_bridge_mdb_entry *mdst;
    struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);

    rcu_read_lock();
#ifdef CONFIG_BRIDGE_NETFILTER
    if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
        br_nf_pre_routing_finish_bridge_slow(skb);
        rcu_read_unlock();
        return NETDEV_TX_OK;
    }
#endif

    u64_stats_update_begin(&brstats->syncp);
    brstats->tx_packets++;
    brstats->tx_bytes += skb->len;
    u64_stats_update_end(&brstats->syncp);

    BR_INPUT_SKB_CB(skb)->brdev = dev;

    skb_reset_mac_header(skb);
    skb_pull(skb, ETH_HLEN);

    if (is_broadcast_ether_addr(dest))
        br_flood_deliver(br, skb);
    else if (is_multicast_ether_addr(dest)) {
        if (unlikely(netpoll_tx_running(dev))) {
            br_flood_deliver(br, skb);
            goto out;
        }
        if (br_multicast_rcv(br, NULL, skb)) {
            kfree_skb(skb);
            goto out;
        }

        mdst = br_mdb_get(br, skb);
        if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb))
            br_multicast_deliver(mdst, skb);
        else
            br_flood_deliver(br, skb);
    } else if ((dst = __br_fdb_get(br, dest)) != NULL)
        br_deliver(dst->dst, skb);
    else
        br_flood_deliver(br, skb);

out:
    rcu_read_unlock();
    return NETDEV_TX_OK;
}

static int br_dev_init(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);

    br->stats = alloc_percpu(struct br_cpu_netstats);
    if (!br->stats)
        return -ENOMEM;

    return 0;
}

static int br_dev_open(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);

    netdev_update_features(dev);
    netif_start_queue(dev);
    br_stp_enable_bridge(br);
    br_multicast_open(br);

    return 0;
}

static void br_dev_set_multicast_list(struct net_device *dev)
{
}

static int br_dev_stop(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);

    br_stp_disable_bridge(br);
    br_multicast_stop(br);

    netif_stop_queue(dev);

    return 0;
}

static struct rtnl_link_stats64 *br_get_stats64(struct net_device *dev,
                        struct rtnl_link_stats64 *stats)
{
    struct net_bridge *br = netdev_priv(dev);
    struct br_cpu_netstats tmp, sum = { 0 };
    unsigned int cpu;

    for_each_possible_cpu(cpu) {
        unsigned int start;
        const struct br_cpu_netstats *bstats
            = per_cpu_ptr(br->stats, cpu);
        do {
            start = u64_stats_fetch_begin_bh(&bstats->syncp);
            memcpy(&tmp, bstats, sizeof(tmp));
        } while (u64_stats_fetch_retry_bh(&bstats->syncp, start));
        sum.tx_bytes   += tmp.tx_bytes;
        sum.tx_packets += tmp.tx_packets;
        sum.rx_bytes   += tmp.rx_bytes;
        sum.rx_packets += tmp.rx_packets;
    }

    stats->tx_bytes   = sum.tx_bytes;
    stats->tx_packets = sum.tx_packets;
    stats->rx_bytes   = sum.rx_bytes;
    stats->rx_packets = sum.rx_packets;

    return stats;
}

static int br_change_mtu(struct net_device *dev, int new_mtu)
{
    struct net_bridge *br = netdev_priv(dev);
    if (new_mtu < 68 || new_mtu > br_min_mtu(br))
        return -EINVAL;

    dev->mtu = new_mtu;

#ifdef CONFIG_BRIDGE_NETFILTER
    /* remember the MTU in the rtable for PMTU */
    dst_metric_set(&br->fake_rtable.dst, RTAX_MTU, new_mtu);
#endif

    return 0;
}

/* Allow setting mac address to any valid ethernet address. */
static int br_set_mac_address(struct net_device *dev, void *p)
{
    struct net_bridge *br = netdev_priv(dev);
    struct sockaddr *addr = p;

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

    spin_lock_bh(&br->lock);
    if (!ether_addr_equal(dev->dev_addr, addr->sa_data)) {
        dev->addr_assign_type &= ~NET_ADDR_RANDOM;
        memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
        br_fdb_change_mac_address(br, addr->sa_data);
        br_stp_change_bridge_id(br, addr->sa_data);
    }
    br->flags |= BR_SET_MAC_ADDR;
    spin_unlock_bh(&br->lock);

    return 0;
}

static void br_getinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
    strcpy(info->driver, "bridge");
    strcpy(info->version, BR_VERSION);
    strcpy(info->fw_version, "N/A");
    strcpy(info->bus_info, "N/A");
}

static netdev_features_t br_fix_features(struct net_device *dev,
    netdev_features_t features)
{
    struct net_bridge *br = netdev_priv(dev);

    return br_features_recompute(br, features);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void br_poll_controller(struct net_device *br_dev)
{
}

static void br_netpoll_cleanup(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);
    struct net_bridge_port *p;

    list_for_each_entry(p, &br->port_list, list)
        br_netpoll_disable(p);
}

static int br_netpoll_setup(struct net_device *dev, struct netpoll_info *ni,
                gfp_t gfp)
{
    struct net_bridge *br = netdev_priv(dev);
    struct net_bridge_port *p;
    int err = 0;

    list_for_each_entry(p, &br->port_list, list) {
        if (!p->dev)
            continue;
        err = br_netpoll_enable(p, gfp);
        if (err)
            goto fail;
    }

out:
    return err;

fail:
    br_netpoll_cleanup(dev);
    goto out;
}

int br_netpoll_enable(struct net_bridge_port *p, gfp_t gfp)
{
    struct netpoll *np;
    int err = 0;

    np = kzalloc(sizeof(*p->np), gfp);
    err = -ENOMEM;
    if (!np)
        goto out;

    err = __netpoll_setup(np, p->dev, gfp);
    if (err) {
        kfree(np);
        goto out;
    }

    p->np = np;

out:
    return err;
}

void br_netpoll_disable(struct net_bridge_port *p)
{
    struct netpoll *np = p->np;

    if (!np)
        return;

    p->np = NULL;

    __netpoll_free_rcu(np);
}

#endif

static int br_add_slave(struct net_device *dev, struct net_device *slave_dev)

{
    struct net_bridge *br = netdev_priv(dev);

    return br_add_if(br, slave_dev);
}

static int br_del_slave(struct net_device *dev, struct net_device *slave_dev)
{
    struct net_bridge *br = netdev_priv(dev);

    return br_del_if(br, slave_dev);
}

static const struct ethtool_ops br_ethtool_ops = {
    .get_drvinfo    = br_getinfo,
    .get_link   = ethtool_op_get_link,
};

static const struct net_device_ops br_netdev_ops = {
    .ndo_open        = br_dev_open,
    .ndo_stop        = br_dev_stop,
    .ndo_init        = br_dev_init,
    .ndo_start_xmit      = br_dev_xmit,
    .ndo_get_stats64     = br_get_stats64,
    .ndo_set_mac_address     = br_set_mac_address,
    .ndo_set_rx_mode     = br_dev_set_multicast_list,
    .ndo_change_mtu      = br_change_mtu,
    .ndo_do_ioctl        = br_dev_ioctl,
#ifdef CONFIG_NET_POLL_CONTROLLER
    .ndo_netpoll_setup   = br_netpoll_setup,
    .ndo_netpoll_cleanup     = br_netpoll_cleanup,
    .ndo_poll_controller     = br_poll_controller,
#endif
    .ndo_add_slave       = br_add_slave,
    .ndo_del_slave       = br_del_slave,
    .ndo_fix_features        = br_fix_features,
    .ndo_fdb_add         = br_fdb_add,
    .ndo_fdb_del         = br_fdb_delete,
    .ndo_fdb_dump        = br_fdb_dump,
};

static void br_dev_free(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);

    free_percpu(br->stats);
    free_netdev(dev);
}

static struct device_type br_type = {
    .name   = "bridge",
};

void br_dev_setup(struct net_device *dev)
{
    struct net_bridge *br = netdev_priv(dev);

    eth_hw_addr_random(dev);
    ether_setup(dev);

    dev->netdev_ops = &br_netdev_ops;
    dev->destructor = br_dev_free;
    SET_ETHTOOL_OPS(dev, &br_ethtool_ops);
    SET_NETDEV_DEVTYPE(dev, &br_type);
    dev->tx_queue_len = 0;
    dev->priv_flags = IFF_EBRIDGE;

    dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
            NETIF_F_GSO_MASK | NETIF_F_HW_CSUM | NETIF_F_LLTX |
            NETIF_F_NETNS_LOCAL | NETIF_F_HW_VLAN_TX;
    dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
               NETIF_F_GSO_MASK | NETIF_F_HW_CSUM |
               NETIF_F_HW_VLAN_TX;

    br->dev = dev;
    spin_lock_init(&br->lock);
    INIT_LIST_HEAD(&br->port_list);
    spin_lock_init(&br->hash_lock);

    br->bridge_id.prio[0] = 0x80;
    br->bridge_id.prio[1] = 0x00;

    memcpy(br->group_addr, br_group_address, ETH_ALEN);

    br->stp_enabled = BR_NO_STP;
    br->group_fwd_mask = BR_GROUPFWD_DEFAULT;

    br->designated_root = br->bridge_id;
    br->bridge_max_age = br->max_age = 20 * HZ;
    br->bridge_hello_time = br->hello_time = 2 * HZ;
    br->bridge_forward_delay = br->forward_delay = 15 * HZ;
    br->ageing_time = 300 * HZ;

    br_netfilter_rtable_init(br);
    br_stp_timer_init(br);
    br_multicast_init(br);
}