[deliverable/linux.git] / net / hsr / hsr_device.c

/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * 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.
 *
 * Author(s):
 *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
 *
 * This file contains device methods for creating, using and destroying
 * virtual HSR devices.
 */

#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_sched.h>
#include "hsr_device.h"
#include "hsr_slave.h"
#include "hsr_framereg.h"
#include "hsr_main.h"


static bool is_admin_up(struct net_device *dev)
{
        return dev && (dev->flags & IFF_UP);
}

static bool is_slave_up(struct net_device *dev)
{
        return dev && is_admin_up(dev) && netif_oper_up(dev);
}

static void __hsr_set_operstate(struct net_device *dev, int transition)
{
        write_lock_bh(&dev_base_lock);
        if (dev->operstate != transition) {
                dev->operstate = transition;
                write_unlock_bh(&dev_base_lock);
                netdev_state_change(dev);
        } else {
                write_unlock_bh(&dev_base_lock);
        }
}

static void hsr_set_operstate(struct net_device *hsr_dev, bool has_carrier)
{
        if (!is_admin_up(hsr_dev)) {
                __hsr_set_operstate(hsr_dev, IF_OPER_DOWN);
                return;
        }

        if (has_carrier)
                __hsr_set_operstate(hsr_dev, IF_OPER_UP);
        else
                __hsr_set_operstate(hsr_dev, IF_OPER_LOWERLAYERDOWN);
}

static bool hsr_check_carrier(struct hsr_priv *hsr)
{
        bool has_carrier;

        has_carrier = (is_slave_up(hsr->slave[0]) || is_slave_up(hsr->slave[1]));

        if (has_carrier)
                netif_carrier_on(hsr->dev);
        else
                netif_carrier_off(hsr->dev);

        return has_carrier;
}


static void hsr_check_announce(struct net_device *hsr_dev,
                               unsigned char old_operstate)
{
        struct hsr_priv *hsr;

        hsr = netdev_priv(hsr_dev);

        if ((hsr_dev->operstate == IF_OPER_UP) && (old_operstate != IF_OPER_UP)) {
                /* Went up */
                hsr->announce_count = 0;
                hsr->announce_timer.expires = jiffies +
                                msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
                add_timer(&hsr->announce_timer);
        }

        if ((hsr_dev->operstate != IF_OPER_UP) && (old_operstate == IF_OPER_UP))
                /* Went down */
                del_timer(&hsr->announce_timer);
}

void hsr_check_carrier_and_operstate(struct hsr_priv *hsr)
{
        unsigned char old_operstate;
        bool has_carrier;

        /* netif_stacked_transfer_operstate() cannot be used here since
         * it doesn't set IF_OPER_LOWERLAYERDOWN (?)
         */
        old_operstate = hsr->dev->operstate;
        has_carrier = hsr_check_carrier(hsr);
        hsr_set_operstate(hsr->dev, has_carrier);
        hsr_check_announce(hsr->dev, old_operstate);
}

int hsr_get_max_mtu(struct hsr_priv *hsr)
{
        unsigned int mtu_max;
        struct net_device *slave;

        mtu_max = ETH_DATA_LEN;
        rcu_read_lock();
        slave = hsr->slave[0];
        if (slave)
                mtu_max = min(slave->mtu, mtu_max);
        slave = hsr->slave[1];
        if (slave)
                mtu_max = min(slave->mtu, mtu_max);
        rcu_read_unlock();

        if (mtu_max < HSR_HLEN)
                return 0;
        return mtu_max - HSR_HLEN;
}


static int hsr_dev_change_mtu(struct net_device *dev, int new_mtu)
{
        struct hsr_priv *hsr;

        hsr = netdev_priv(dev);

        if (new_mtu > hsr_get_max_mtu(hsr)) {
                netdev_info(hsr->dev, "A HSR master's MTU cannot be greater than the smallest MTU of its slaves minus the HSR Tag length (%d octets).\n",
                            HSR_HLEN);
                return -EINVAL;
        }

        dev->mtu = new_mtu;

        return 0;
}

static int hsr_dev_open(struct net_device *dev)
{
        struct hsr_priv *hsr;
        struct net_device *slave;
        int i;
        char *slave_name;

        hsr = netdev_priv(dev);

        for (i = 0; i < HSR_MAX_SLAVE; i++) {
                slave = hsr->slave[i];
                if (slave)
                        slave_name = slave->name;
                else
                        slave_name = "null";

                if (!is_slave_up(slave))
                        netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a working HSR network\n",
                                    'A' + i, slave_name);
        }

        return 0;
}

static int hsr_dev_close(struct net_device *dev)
{
        /* Nothing to do here. We could try to restore the state of the slaves
         * to what they were before being changed by the hsr master dev's state,
         * but they might have been changed manually in the mean time too, so
         * taking them up or down here might be confusing and is probably not a
         * good idea.
         */
        return 0;
}


static void hsr_fill_tag(struct hsr_ethhdr *hsr_ethhdr, struct hsr_priv *hsr)
{
        unsigned long irqflags;

        /* IEC 62439-1:2010, p 48, says the 4-bit "path" field can take values
         * between 0001-1001 ("ring identifier", for regular HSR frames),
         * or 1111 ("HSR management", supervision frames). Unfortunately, the
         * spec writers forgot to explain what a "ring identifier" is, or
         * how it is used. So we just set this to 0001 for regular frames,
         * and 1111 for supervision frames.
         */
        set_hsr_tag_path(&hsr_ethhdr->hsr_tag, 0x1);

        /* IEC 62439-1:2010, p 12: "The link service data unit in an Ethernet
         * frame is the content of the frame located between the Length/Type
         * field and the Frame Check Sequence."
         *
         * IEC 62439-3, p 48, specifies the "original LPDU" to include the
         * original "LT" field (what "LT" means is not explained anywhere as
         * far as I can see - perhaps "Length/Type"?). So LSDU_size might
         * equal original length + 2.
         *   Also, the fact that this field is not used anywhere (might be used
         * by a RedBox connecting HSR and PRP nets?) means I cannot test its
         * correctness. Instead of guessing, I set this to 0 here, to make any
         * problems immediately apparent. Anyone using this driver with PRP/HSR
         * RedBoxes might need to fix this...
         */
        set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, 0);

        spin_lock_irqsave(&hsr->seqnr_lock, irqflags);
        hsr_ethhdr->hsr_tag.sequence_nr = htons(hsr->sequence_nr);
        hsr->sequence_nr++;
        spin_unlock_irqrestore(&hsr->seqnr_lock, irqflags);

        hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;

        hsr_ethhdr->ethhdr.h_proto = htons(ETH_P_PRP);
}

static int slave_xmit(struct sk_buff *skb, struct hsr_priv *hsr,
                      enum hsr_dev_idx dev_idx)
{
        struct hsr_ethhdr *hsr_ethhdr;

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

        skb->dev = hsr->slave[dev_idx];
        if (unlikely(!skb->dev))
                return NET_XMIT_DROP;

        hsr_addr_subst_dest(hsr, &hsr_ethhdr->ethhdr, dev_idx);

        /* Address substitution (IEC62439-3 pp 26, 50): replace mac
         * address of outgoing frame with that of the outgoing slave's.
         */
        ether_addr_copy(hsr_ethhdr->ethhdr.h_source, skb->dev->dev_addr);

        return dev_queue_xmit(skb);
}


static int hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct hsr_priv *hsr;
        struct hsr_ethhdr *hsr_ethhdr;
        struct sk_buff *skb2;
        int res1, res2;

        hsr = netdev_priv(dev);
        hsr_ethhdr = (struct hsr_ethhdr *) skb->data;

        if ((skb->protocol != htons(ETH_P_PRP)) ||
            (hsr_ethhdr->ethhdr.h_proto != htons(ETH_P_PRP))) {
                hsr_fill_tag(hsr_ethhdr, hsr);
                skb->protocol = htons(ETH_P_PRP);
        }

        skb2 = pskb_copy(skb, GFP_ATOMIC);
        res1 = slave_xmit(skb, hsr, HSR_DEV_SLAVE_A);
        res2 = slave_xmit(skb2, hsr, HSR_DEV_SLAVE_B);

        if (likely(res1 == NET_XMIT_SUCCESS || res1 == NET_XMIT_CN ||
                   res2 == NET_XMIT_SUCCESS || res2 == NET_XMIT_CN)) {
                hsr->dev->stats.tx_packets++;
                hsr->dev->stats.tx_bytes += skb->len;
        } else {
                hsr->dev->stats.tx_dropped++;
        }

        return NETDEV_TX_OK;
}


static int hsr_header_create(struct sk_buff *skb, struct net_device *dev,
                             unsigned short type, const void *daddr,
                             const void *saddr, unsigned int len)
{
        int res;

        /* Make room for the HSR tag now. We will fill it in later (in
         * hsr_dev_xmit)
         */
        if (skb_headroom(skb) < HSR_HLEN + ETH_HLEN)
                return -ENOBUFS;
        skb_push(skb, HSR_HLEN);

        /* To allow VLAN/HSR combos we should probably use
         * res = dev_hard_header(skb, dev, type, daddr, saddr, len + HSR_HLEN);
         * here instead. It would require other changes too, though - e.g.
         * separate headers for each slave etc...
         */
        res = eth_header(skb, dev, type, daddr, saddr, len + HSR_HLEN);
        if (res <= 0)
                return res;
        skb_reset_mac_header(skb);

        return res + HSR_HLEN;
}


static const struct header_ops hsr_header_ops = {
        .create  = hsr_header_create,
        .parse   = eth_header_parse,
};


/* HSR:2010 supervision frames should be padded so that the whole frame,
 * including headers and FCS, is 64 bytes (without VLAN).
 */
static int hsr_pad(int size)
{
        const int min_size = ETH_ZLEN - HSR_HLEN - ETH_HLEN;

        if (size >= min_size)
                return size;
        return min_size;
}

static void send_hsr_supervision_frame(struct net_device *hsr_dev, u8 type)
{
        struct hsr_priv *hsr;
        struct sk_buff *skb;
        int hlen, tlen;
        struct hsr_sup_tag *hsr_stag;
        struct hsr_sup_payload *hsr_sp;
        unsigned long irqflags;

        hlen = LL_RESERVED_SPACE(hsr_dev);
        tlen = hsr_dev->needed_tailroom;
        skb = alloc_skb(hsr_pad(sizeof(struct hsr_sup_payload)) + hlen + tlen,
                        GFP_ATOMIC);

        if (skb == NULL)
                return;

        hsr = netdev_priv(hsr_dev);

        skb_reserve(skb, hlen);

        skb->dev = hsr_dev;
        skb->protocol = htons(ETH_P_PRP);
        skb->priority = TC_PRIO_CONTROL;

        if (dev_hard_header(skb, skb->dev, ETH_P_PRP,
                            hsr->sup_multicast_addr,
                            skb->dev->dev_addr, skb->len) < 0)
                goto out;

        skb_pull(skb, sizeof(struct ethhdr));
        hsr_stag = (typeof(hsr_stag)) skb->data;

        set_hsr_stag_path(hsr_stag, 0xf);
        set_hsr_stag_HSR_Ver(hsr_stag, 0);

        spin_lock_irqsave(&hsr->seqnr_lock, irqflags);
        hsr_stag->sequence_nr = htons(hsr->sequence_nr);
        hsr->sequence_nr++;
        spin_unlock_irqrestore(&hsr->seqnr_lock, irqflags);

        hsr_stag->HSR_TLV_Type = type;
        hsr_stag->HSR_TLV_Length = 12;

        skb_push(skb, sizeof(struct ethhdr));

        /* Payload: MacAddressA */
        hsr_sp = (typeof(hsr_sp)) skb_put(skb, sizeof(*hsr_sp));
        ether_addr_copy(hsr_sp->MacAddressA, hsr_dev->dev_addr);

        dev_queue_xmit(skb);
        return;

out:
        kfree_skb(skb);
}


/* Announce (supervision frame) timer function
 */
static void hsr_announce(unsigned long data)
{
        struct hsr_priv *hsr;

        hsr = (struct hsr_priv *) data;

        if (hsr->announce_count < 3) {
                send_hsr_supervision_frame(hsr->dev, HSR_TLV_ANNOUNCE);
                hsr->announce_count++;
        } else {
                send_hsr_supervision_frame(hsr->dev, HSR_TLV_LIFE_CHECK);
        }

        if (hsr->announce_count < 3)
                hsr->announce_timer.expires = jiffies +
                                msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
        else
                hsr->announce_timer.expires = jiffies +
                                msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);

        if (is_admin_up(hsr->dev))
                add_timer(&hsr->announce_timer);
}


static void restore_slaves(struct net_device *hsr_dev)
{
        struct hsr_priv *hsr;

        hsr = netdev_priv(hsr_dev);
        hsr_del_slave(hsr, 1);
        hsr_del_slave(hsr, 0);
}

static void reclaim_hsr_dev(struct rcu_head *rh)
{
        struct hsr_priv *hsr;

        hsr = container_of(rh, struct hsr_priv, rcu_head);
        free_netdev(hsr->dev);
}


/* According to comments in the declaration of struct net_device, this function
 * is "Called from unregister, can be used to call free_netdev". Ok then...
 */
static void hsr_dev_destroy(struct net_device *hsr_dev)
{
        struct hsr_priv *hsr;

        hsr = netdev_priv(hsr_dev);

        del_timer_sync(&hsr->prune_timer);
        del_timer_sync(&hsr->announce_timer);
        unregister_hsr_master(hsr);    /* calls list_del_rcu on hsr */
        restore_slaves(hsr_dev);
        call_rcu(&hsr->rcu_head, reclaim_hsr_dev);   /* reclaim hsr */
}

static const struct net_device_ops hsr_device_ops = {
        .ndo_change_mtu = hsr_dev_change_mtu,
        .ndo_open = hsr_dev_open,
        .ndo_stop = hsr_dev_close,
        .ndo_start_xmit = hsr_dev_xmit,
};


void hsr_dev_setup(struct net_device *dev)
{
        random_ether_addr(dev->dev_addr);

        ether_setup(dev);
        dev->header_ops          = &hsr_header_ops;
        dev->netdev_ops          = &hsr_device_ops;
        dev->tx_queue_len        = 0;

        dev->destructor = hsr_dev_destroy;
}


/* Return true if dev is a HSR master; return false otherwise.
 */
bool is_hsr_master(struct net_device *dev)
{
        return (dev->netdev_ops->ndo_start_xmit == hsr_dev_xmit);
}


/* Default multicast address for HSR Supervision frames */
static const unsigned char def_multicast_addr[ETH_ALEN] __aligned(2) = {
        0x01, 0x15, 0x4e, 0x00, 0x01, 0x00
};

int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
                     unsigned char multicast_spec)
{
        struct hsr_priv *hsr;
        int res;

        hsr = netdev_priv(hsr_dev);
        hsr->dev = hsr_dev;
        hsr->slave[0] = NULL;
        hsr->slave[1] = NULL;
        INIT_LIST_HEAD(&hsr->node_db);
        INIT_LIST_HEAD(&hsr->self_node_db);

        ether_addr_copy(hsr_dev->dev_addr, slave[0]->dev_addr);

        /* Make sure we recognize frames from ourselves in hsr_rcv() */
        res = hsr_create_self_node(&hsr->self_node_db, hsr_dev->dev_addr,
                                   slave[1]->dev_addr);
        if (res < 0)
                return res;

        hsr_dev->features = slave[0]->features & slave[1]->features;
        /* Prevent recursive tx locking */
        hsr_dev->features |= NETIF_F_LLTX;
        /* VLAN on top of HSR needs testing and probably some work on
         * hsr_header_create() etc.
         */
        hsr_dev->features |= NETIF_F_VLAN_CHALLENGED;

        spin_lock_init(&hsr->seqnr_lock);
        /* Overflow soon to find bugs easier: */
        hsr->sequence_nr = USHRT_MAX - 1024;

        init_timer(&hsr->announce_timer);
        hsr->announce_timer.function = hsr_announce;
        hsr->announce_timer.data = (unsigned long) hsr;

        init_timer(&hsr->prune_timer);
        hsr->prune_timer.function = hsr_prune_nodes;
        hsr->prune_timer.data = (unsigned long) hsr;

        ether_addr_copy(hsr->sup_multicast_addr, def_multicast_addr);
        hsr->sup_multicast_addr[ETH_ALEN - 1] = multicast_spec;

/* FIXME: should I modify the value of these?
 *
 * - hsr_dev->flags - i.e.
 *                      IFF_MASTER/SLAVE?
 * - hsr_dev->priv_flags - i.e.
 *                      IFF_EBRIDGE?
 *                      IFF_TX_SKB_SHARING?
 *                      IFF_HSR_MASTER/SLAVE?
 */

        /* Make sure the 1st call to netif_carrier_on() gets through */
        netif_carrier_off(hsr_dev);

        res = register_netdevice(hsr_dev);
        if (res)
                return res;

        res = hsr_add_slave(hsr, slave[0], 0);
        if (res)
                return res;
        res = hsr_add_slave(hsr, slave[1], 1);
        if (res) {
                hsr_del_slave(hsr, 0);
                return res;
        }

        hsr->prune_timer.expires = jiffies + msecs_to_jiffies(PRUNE_PERIOD);
        add_timer(&hsr->prune_timer);

        register_hsr_master(hsr);

        return 0;
}