// SPDX-License-Identifier: GPL-2.0
/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * Author(s):
 *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
 * This file contains device methods for creating, using and destroying
 * virtual HSR or PRP 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"
#include "hsr_forward.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 hsr_port *master, bool has_carrier)
{
        if (!is_admin_up(master->dev)) {
                __hsr_set_operstate(master->dev, IF_OPER_DOWN);
                return;
        }

        if (has_carrier)
                __hsr_set_operstate(master->dev, IF_OPER_UP);
        else
                __hsr_set_operstate(master->dev, IF_OPER_LOWERLAYERDOWN);
}

static bool hsr_check_carrier(struct hsr_port *master)
{
        struct hsr_port *port;

        ASSERT_RTNL();

        hsr_for_each_port(master->hsr, port) {
                if (port->type != HSR_PT_MASTER && is_slave_up(port->dev)) {
                        netif_carrier_on(master->dev);
                        return true;
                }
        }

        netif_carrier_off(master->dev);

        return false;
}

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;
                mod_timer(&hsr->announce_timer,
                          jiffies + msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL));
        }

        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)
{
        struct hsr_port *master;
        unsigned char old_operstate;
        bool has_carrier;

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

int hsr_get_max_mtu(struct hsr_priv *hsr)
{
        unsigned int mtu_max;
        struct hsr_port *port;

        mtu_max = ETH_DATA_LEN;
        hsr_for_each_port(hsr, port)
                if (port->type != HSR_PT_MASTER)
                        mtu_max = min(port->dev->mtu, mtu_max);

        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(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 hsr_port *port;
        char designation;

        hsr = netdev_priv(dev);
        designation = '\0';

        hsr_for_each_port(hsr, port) {
                if (port->type == HSR_PT_MASTER)
                        continue;
                switch (port->type) {
                case HSR_PT_SLAVE_A:
                        designation = 'A';
                        break;
                case HSR_PT_SLAVE_B:
                        designation = 'B';
                        break;
                default:
                        designation = '?';
                }
                if (!is_slave_up(port->dev))
                        netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a fully working HSR network\n",
                                    designation, port->dev->name);
        }

        if (designation == '\0')
                netdev_warn(dev, "No slave devices configured\n");

        return 0;
}

static int hsr_dev_close(struct net_device *dev)
{
        /* Nothing to do here. */
        return 0;
}

static netdev_features_t hsr_features_recompute(struct hsr_priv *hsr,
                                                netdev_features_t features)
{
        netdev_features_t mask;
        struct hsr_port *port;

        mask = features;

        /* Mask out all features that, if supported by one device, should be
         * enabled for all devices (see NETIF_F_ONE_FOR_ALL).
         *
         * Anything that's off in mask will not be enabled - so only things
         * that were in features originally, and also is in NETIF_F_ONE_FOR_ALL,
         * may become enabled.
         */
        features &= ~NETIF_F_ONE_FOR_ALL;
        hsr_for_each_port(hsr, port)
                features = netdev_increment_features(features,
                                                     port->dev->features,
                                                     mask);

        return features;
}

static netdev_features_t hsr_fix_features(struct net_device *dev,
                                          netdev_features_t features)
{
        struct hsr_priv *hsr = netdev_priv(dev);

        return hsr_features_recompute(hsr, features);
}

static netdev_tx_t hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct hsr_priv *hsr = netdev_priv(dev);
        struct hsr_port *master;

        master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        if (master) {
                skb->dev = master->dev;
                skb_reset_mac_header(skb);
                skb_reset_mac_len(skb);
                hsr_forward_skb(skb, master);
        } else {
                atomic_long_inc(&dev->tx_dropped);
                dev_kfree_skb_any(skb);
        }
        return NETDEV_TX_OK;
}

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

static struct sk_buff *hsr_init_skb(struct hsr_port *master)
{
        struct hsr_priv *hsr = master->hsr;
        struct sk_buff *skb;
        int hlen, tlen;

        hlen = LL_RESERVED_SPACE(master->dev);
        tlen = master->dev->needed_tailroom;
        /* skb size is same for PRP/HSR frames, only difference
         * being, for PRP it is a trailer and for HSR it is a
         * header
         */
        skb = dev_alloc_skb(sizeof(struct hsr_sup_tag) +
                            sizeof(struct hsr_sup_payload) + hlen + tlen);

        if (!skb)
                return skb;

        skb_reserve(skb, hlen);
        skb->dev = master->dev;
        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_reset_mac_header(skb);
        skb_reset_mac_len(skb);
        skb_reset_network_header(skb);
        skb_reset_transport_header(skb);

        return skb;
out:
        kfree_skb(skb);

        return NULL;
}

static void send_hsr_supervision_frame(struct hsr_port *master,
                                       unsigned long *interval)
{
        struct hsr_priv *hsr = master->hsr;
        __u8 type = HSR_TLV_LIFE_CHECK;
        struct hsr_sup_payload *hsr_sp;
        struct hsr_sup_tag *hsr_stag;
        unsigned long irqflags;
        struct sk_buff *skb;

        *interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
        if (hsr->announce_count < 3 && hsr->prot_version == 0) {
                type = HSR_TLV_ANNOUNCE;
                *interval = msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
                hsr->announce_count++;
        }

        skb = hsr_init_skb(master);
        if (!skb) {
                WARN_ONCE(1, "HSR: Could not send supervision frame\n");
                return;
        }

        hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
        set_hsr_stag_path(hsr_stag, (hsr->prot_version ? 0x0 : 0xf));
        set_hsr_stag_HSR_ver(hsr_stag, hsr->prot_version);

        /* From HSRv1 on we have separate supervision sequence numbers. */
        spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
        if (hsr->prot_version > 0) {
                hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
                hsr->sup_sequence_nr++;
        } else {
                hsr_stag->sequence_nr = htons(hsr->sequence_nr);
                hsr->sequence_nr++;
        }
        spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);

        hsr_stag->HSR_TLV_type = type;
        /* TODO: Why 12 in HSRv0? */
        hsr_stag->HSR_TLV_length = hsr->prot_version ?
                                sizeof(struct hsr_sup_payload) : 12;

        /* Payload: MacAddressA */
        hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
        ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);

        if (skb_put_padto(skb, ETH_ZLEN))
                return;

        hsr_forward_skb(skb, master);

        return;
}

static void send_prp_supervision_frame(struct hsr_port *master,
                                       unsigned long *interval)
{
        struct hsr_priv *hsr = master->hsr;
        struct hsr_sup_payload *hsr_sp;
        struct hsr_sup_tag *hsr_stag;
        unsigned long irqflags;
        struct sk_buff *skb;

        skb = hsr_init_skb(master);
        if (!skb) {
                WARN_ONCE(1, "PRP: Could not send supervision frame\n");
                return;
        }

        *interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
        hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
        set_hsr_stag_path(hsr_stag, (hsr->prot_version ? 0x0 : 0xf));
        set_hsr_stag_HSR_ver(hsr_stag, (hsr->prot_version ? 1 : 0));

        /* From HSRv1 on we have separate supervision sequence numbers. */
        spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
        hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
        hsr->sup_sequence_nr++;
        hsr_stag->HSR_TLV_type = PRP_TLV_LIFE_CHECK_DD;
        hsr_stag->HSR_TLV_length = sizeof(struct hsr_sup_payload);

        /* Payload: MacAddressA */
        hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
        ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);

        if (skb_put_padto(skb, ETH_ZLEN)) {
                spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
                return;
        }

        spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);

        hsr_forward_skb(skb, master);
}

/* Announce (supervision frame) timer function
 */
static void hsr_announce(struct timer_list *t)
{
        struct hsr_priv *hsr;
        struct hsr_port *master;
        unsigned long interval;

        hsr = from_timer(hsr, t, announce_timer);

        rcu_read_lock();
        master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        hsr->proto_ops->send_sv_frame(master, &interval);

        if (is_admin_up(master->dev))
                mod_timer(&hsr->announce_timer, jiffies + interval);

        rcu_read_unlock();
}

void hsr_del_ports(struct hsr_priv *hsr)
{
        struct hsr_port *port;

        port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
        if (port)
                hsr_del_port(port);

        port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
        if (port)
                hsr_del_port(port);

        port = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        if (port)
                hsr_del_port(port);
}

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,
        .ndo_fix_features = hsr_fix_features,
};

static struct device_type hsr_type = {
        .name = "hsr",
};

static struct hsr_proto_ops hsr_ops = {
        .send_sv_frame = send_hsr_supervision_frame,
        .create_tagged_frame = hsr_create_tagged_frame,
        .get_untagged_frame = hsr_get_untagged_frame,
        .drop_frame = hsr_drop_frame,
        .fill_frame_info = hsr_fill_frame_info,
        .invalid_dan_ingress_frame = hsr_invalid_dan_ingress_frame,
};

static struct hsr_proto_ops prp_ops = {
        .send_sv_frame = send_prp_supervision_frame,
        .create_tagged_frame = prp_create_tagged_frame,
        .get_untagged_frame = prp_get_untagged_frame,
        .drop_frame = prp_drop_frame,
        .fill_frame_info = prp_fill_frame_info,
        .handle_san_frame = prp_handle_san_frame,
        .update_san_info = prp_update_san_info,
};

void hsr_dev_setup(struct net_device *dev)
{
        eth_hw_addr_random(dev);

        ether_setup(dev);
        dev->min_mtu = 0;
        dev->header_ops = &hsr_header_ops;
        dev->netdev_ops = &hsr_device_ops;
        SET_NETDEV_DEVTYPE(dev, &hsr_type);
        dev->priv_flags |= IFF_NO_QUEUE;

        dev->needs_free_netdev = true;

        dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
                           NETIF_F_GSO_MASK | NETIF_F_HW_CSUM |
                           NETIF_F_HW_VLAN_CTAG_TX;

        dev->features = dev->hw_features;

        /* Prevent recursive tx locking */
        dev->features |= NETIF_F_LLTX;
        /* VLAN on top of HSR needs testing and probably some work on
         * hsr_header_create() etc.
         */
        dev->features |= NETIF_F_VLAN_CHALLENGED;
        /* Not sure about this. Taken from bridge code. netdev_features.h says
         * it means "Does not change network namespaces".
         */
        dev->features |= NETIF_F_NETNS_LOCAL;
}

/* 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);
}
EXPORT_SYMBOL(is_hsr_master);

/* 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, u8 protocol_version,
                     struct netlink_ext_ack *extack)
{
        bool unregister = false;
        struct hsr_priv *hsr;
        int res;

        hsr = netdev_priv(hsr_dev);
        INIT_LIST_HEAD(&hsr->ports);
        INIT_LIST_HEAD(&hsr->node_db);
        INIT_LIST_HEAD(&hsr->self_node_db);
        spin_lock_init(&hsr->list_lock);

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

        /* initialize protocol specific functions */
        if (protocol_version == PRP_V1) {
                /* For PRP, lan_id has most significant 3 bits holding
                 * the net_id of PRP_LAN_ID
                 */
                hsr->net_id = PRP_LAN_ID << 1;
                hsr->proto_ops = &prp_ops;
        } else {
                hsr->proto_ops = &hsr_ops;
        }

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

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

        timer_setup(&hsr->announce_timer, hsr_announce, 0);
        timer_setup(&hsr->prune_timer, hsr_prune_nodes, 0);

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

        hsr->prot_version = protocol_version;

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

        res = hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER, extack);
        if (res)
                goto err_add_master;

        res = register_netdevice(hsr_dev);
        if (res)
                goto err_unregister;

        unregister = true;

        res = hsr_add_port(hsr, slave[0], HSR_PT_SLAVE_A, extack);
        if (res)
                goto err_unregister;

        res = hsr_add_port(hsr, slave[1], HSR_PT_SLAVE_B, extack);
        if (res)
                goto err_unregister;

        hsr_debugfs_init(hsr, hsr_dev);
        mod_timer(&hsr->prune_timer, jiffies + msecs_to_jiffies(PRUNE_PERIOD));

        return 0;

err_unregister:
        hsr_del_ports(hsr);
err_add_master:
        hsr_del_self_node(hsr);

        if (unregister)
                unregister_netdevice(hsr_dev);
        return res;
}