// 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)) {
		if (!pskb_may_pull(skb, ETH_HLEN + HSR_HLEN)) {
			kfree_skb(skb);
			goto finish_consume;
		}

		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;

	/* Don't use promiscuous mode for offload since L2 frame forward
	 * happens at the offloaded hardware.
	 */
	if (!port->hsr->fwd_offloaded) {
		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:
	if (!port->hsr->fwd_offloaded)
		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);
		if (!port->hsr->fwd_offloaded)
			dev_set_promiscuity(port->dev, -1);
		netdev_upper_dev_unlink(port->dev, master->dev);
	}

	synchronize_rcu();

	kfree(port);
}