// SPDX-License-Identifier: GPL-2.0
/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * Author(s):
 *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
 *
 * Frame handler other utility functions for HSR and PRP.
 */

#include "hsr_slave.h"
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include "hsr_main.h"
#include "hsr_device.h"
#include "hsr_forward.h"
#include "hsr_framereg.h"

bool hsr_invalid_dan_ingress_frame(__be16 protocol)
{
        return (protocol != htons(ETH_P_PRP) && protocol != htons(ETH_P_HSR));
}

static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
{
        struct sk_buff *skb = *pskb;
        struct hsr_port *port;
        struct hsr_priv *hsr;
        __be16 protocol;

        /* Packets from dev_loopback_xmit() do not have L2 header, bail out */
        if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
                return RX_HANDLER_PASS;

        if (!skb_mac_header_was_set(skb)) {
                WARN_ONCE(1, "%s: skb invalid", __func__);
                return RX_HANDLER_PASS;
        }

        port = hsr_port_get_rcu(skb->dev);
        if (!port)
                goto finish_pass;
        hsr = port->hsr;

        if (hsr_addr_is_self(port->hsr, eth_hdr(skb)->h_source)) {
                /* Directly kill frames sent by ourselves */
                kfree_skb(skb);
                goto finish_consume;
        }

        /* For HSR, only tagged frames are expected (unless the device offloads
         * HSR tag removal), but for PRP there could be non tagged frames as
         * well from Single attached nodes (SANs).
         */
        protocol = eth_hdr(skb)->h_proto;

        if (!(port->dev->features & NETIF_F_HW_HSR_TAG_RM) &&
            hsr->proto_ops->invalid_dan_ingress_frame &&
            hsr->proto_ops->invalid_dan_ingress_frame(protocol))
                goto finish_pass;

        skb_push(skb, ETH_HLEN);
        skb_reset_mac_header(skb);
        if ((!hsr->prot_version && protocol == htons(ETH_P_PRP)) ||
            protocol == htons(ETH_P_HSR))
                skb_set_network_header(skb, ETH_HLEN + HSR_HLEN);
        skb_reset_mac_len(skb);

        hsr_forward_skb(skb, port);

finish_consume:
        return RX_HANDLER_CONSUMED;

finish_pass:
        return RX_HANDLER_PASS;
}

bool hsr_port_exists(const struct net_device *dev)
{
        return rcu_access_pointer(dev->rx_handler) == hsr_handle_frame;
}

static int hsr_check_dev_ok(struct net_device *dev,
                            struct netlink_ext_ack *extack)
{
        /* Don't allow HSR on non-ethernet like devices */
        if ((dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
            dev->addr_len != ETH_ALEN) {
                NL_SET_ERR_MSG_MOD(extack, "Cannot use loopback or non-ethernet device as HSR slave.");
                return -EINVAL;
        }

        /* Don't allow enslaving hsr devices */
        if (is_hsr_master(dev)) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Cannot create trees of HSR devices.");
                return -EINVAL;
        }

        if (hsr_port_exists(dev)) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "This device is already a HSR slave.");
                return -EINVAL;
        }

        if (is_vlan_dev(dev)) {
                NL_SET_ERR_MSG_MOD(extack, "HSR on top of VLAN is not yet supported in this driver.");
                return -EINVAL;
        }

        if (dev->priv_flags & IFF_DONT_BRIDGE) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "This device does not support bridging.");
                return -EOPNOTSUPP;
        }

        /* HSR over bonded devices has not been tested, but I'm not sure it
         * won't work...
         */

        return 0;
}

/* Setup device to be added to the HSR bridge. */
static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev,
                             struct hsr_port *port,
                             struct netlink_ext_ack *extack)

{
        struct net_device *hsr_dev;
        struct hsr_port *master;
        int res;

        res = dev_set_promiscuity(dev, 1);
        if (res)
                return res;

        master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        hsr_dev = master->dev;

        res = netdev_upper_dev_link(dev, hsr_dev, extack);
        if (res)
                goto fail_upper_dev_link;

        res = netdev_rx_handler_register(dev, hsr_handle_frame, port);
        if (res)
                goto fail_rx_handler;
        dev_disable_lro(dev);

        return 0;

fail_rx_handler:
        netdev_upper_dev_unlink(dev, hsr_dev);
fail_upper_dev_link:
        dev_set_promiscuity(dev, -1);
        return res;
}

int hsr_add_port(struct hsr_priv *hsr, struct net_device *dev,
                 enum hsr_port_type type, struct netlink_ext_ack *extack)
{
        struct hsr_port *port, *master;
        int res;

        if (type != HSR_PT_MASTER) {
                res = hsr_check_dev_ok(dev, extack);
                if (res)
                        return res;
        }

        port = hsr_port_get_hsr(hsr, type);
        if (port)
                return -EBUSY;  /* This port already exists */

        port = kzalloc(sizeof(*port), GFP_KERNEL);
        if (!port)
                return -ENOMEM;

        port->hsr = hsr;
        port->dev = dev;
        port->type = type;

        if (type != HSR_PT_MASTER) {
                res = hsr_portdev_setup(hsr, dev, port, extack);
                if (res)
                        goto fail_dev_setup;
        }

        list_add_tail_rcu(&port->port_list, &hsr->ports);
        synchronize_rcu();

        master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        netdev_update_features(master->dev);
        dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));

        return 0;

fail_dev_setup:
        kfree(port);
        return res;
}

void hsr_del_port(struct hsr_port *port)
{
        struct hsr_priv *hsr;
        struct hsr_port *master;

        hsr = port->hsr;
        master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
        list_del_rcu(&port->port_list);

        if (port != master) {
                netdev_update_features(master->dev);
                dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
                netdev_rx_handler_unregister(port->dev);
                dev_set_promiscuity(port->dev, -1);
                netdev_upper_dev_unlink(port->dev, master->dev);
        }

        synchronize_rcu();

        kfree(port);
}