/*
 * Copyright(c) 2017 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/*
 * This file contains OPA VNIC encapsulation/decapsulation function.
 */

#include <linux/if_ether.h>
#include <linux/if_vlan.h>

#include "opa_vnic_internal.h"

/* OPA 16B Header fields */
#define OPA_16B_LID_MASK        0xFFFFFull
#define OPA_16B_SLID_HIGH_SHFT  8
#define OPA_16B_SLID_MASK       0xF00ull
#define OPA_16B_DLID_MASK       0xF000ull
#define OPA_16B_DLID_HIGH_SHFT  12
#define OPA_16B_LEN_SHFT        20
#define OPA_16B_SC_SHFT         20
#define OPA_16B_RC_SHFT         25
#define OPA_16B_PKEY_SHFT       16

#define OPA_VNIC_L4_HDR_SHFT    16

/* L2+L4 hdr len is 20 bytes (5 quad words) */
#define OPA_VNIC_HDR_QW_LEN   5

static inline void opa_vnic_make_header(u8 *hdr, u32 slid, u32 dlid, u16 len,
					u16 pkey, u16 entropy, u8 sc, u8 rc,
					u8 l4_type, u16 l4_hdr)
{
	/* h[1]: LT=1, 16B L2=10 */
	u32 h[OPA_VNIC_HDR_QW_LEN] = {0, 0xc0000000, 0, 0, 0};

	h[2] = l4_type;
	h[3] = entropy;
	h[4] = l4_hdr << OPA_VNIC_L4_HDR_SHFT;

	/* Extract and set 4 upper bits and 20 lower bits of the lids */
	h[0] |= (slid & OPA_16B_LID_MASK);
	h[2] |= ((slid >> (20 - OPA_16B_SLID_HIGH_SHFT)) & OPA_16B_SLID_MASK);

	h[1] |= (dlid & OPA_16B_LID_MASK);
	h[2] |= ((dlid >> (20 - OPA_16B_DLID_HIGH_SHFT)) & OPA_16B_DLID_MASK);

	h[0] |= (len << OPA_16B_LEN_SHFT);
	h[1] |= (rc << OPA_16B_RC_SHFT);
	h[1] |= (sc << OPA_16B_SC_SHFT);
	h[2] |= ((u32)pkey << OPA_16B_PKEY_SHFT);

	memcpy(hdr, h, OPA_VNIC_HDR_LEN);
}

/*
 * Using a simple hash table for mac table implementation with the last octet
 * of mac address as a key.
 */
static void opa_vnic_free_mac_tbl(struct hlist_head *mactbl)
{
	struct opa_vnic_mac_tbl_node *node;
	struct hlist_node *tmp;
	int bkt;

	if (!mactbl)
		return;

	vnic_hash_for_each_safe(mactbl, bkt, tmp, node, hlist) {
		hash_del(&node->hlist);
		kfree(node);
	}
	kfree(mactbl);
}

static struct hlist_head *opa_vnic_alloc_mac_tbl(void)
{
	u32 size = sizeof(struct hlist_head) * OPA_VNIC_MAC_TBL_SIZE;
	struct hlist_head *mactbl;

	mactbl = kzalloc(size, GFP_KERNEL);
	if (!mactbl)
		return ERR_PTR(-ENOMEM);

	vnic_hash_init(mactbl);
	return mactbl;
}

/* opa_vnic_release_mac_tbl - empty and free the mac table */
void opa_vnic_release_mac_tbl(struct opa_vnic_adapter *adapter)
{
	struct hlist_head *mactbl;

	mutex_lock(&adapter->mactbl_lock);
	mactbl = rcu_access_pointer(adapter->mactbl);
	rcu_assign_pointer(adapter->mactbl, NULL);
	synchronize_rcu();
	opa_vnic_free_mac_tbl(mactbl);
	adapter->info.vport.mac_tbl_digest = 0;
	mutex_unlock(&adapter->mactbl_lock);
}

/*
 * opa_vnic_query_mac_tbl - query the mac table for a section
 *
 * This function implements query of specific function of the mac table.
 * The function also expects the requested range to be valid.
 */
void opa_vnic_query_mac_tbl(struct opa_vnic_adapter *adapter,
			    struct opa_veswport_mactable *tbl)
{
	struct opa_vnic_mac_tbl_node *node;
	struct hlist_head *mactbl;
	int bkt;
	u16 loffset, lnum_entries;

	rcu_read_lock();
	mactbl = rcu_dereference(adapter->mactbl);
	if (!mactbl)
		goto get_mac_done;

	loffset = be16_to_cpu(tbl->offset);
	lnum_entries = be16_to_cpu(tbl->num_entries);

	vnic_hash_for_each(mactbl, bkt, node, hlist) {
		struct __opa_vnic_mactable_entry *nentry = &node->entry;
		struct opa_veswport_mactable_entry *entry;

		if ((node->index < loffset) ||
		    (node->index >= (loffset + lnum_entries)))
			continue;

		/* populate entry in the tbl corresponding to the index */
		entry = &tbl->tbl_entries[node->index - loffset];
		memcpy(entry->mac_addr, nentry->mac_addr,
		       ARRAY_SIZE(entry->mac_addr));
		memcpy(entry->mac_addr_mask, nentry->mac_addr_mask,
		       ARRAY_SIZE(entry->mac_addr_mask));
		entry->dlid_sd = cpu_to_be32(nentry->dlid_sd);
	}
	tbl->mac_tbl_digest = cpu_to_be32(adapter->info.vport.mac_tbl_digest);
get_mac_done:
	rcu_read_unlock();
}

/*
 * opa_vnic_update_mac_tbl - update mac table section
 *
 * This function updates the specified section of the mac table.
 * The procedure includes following steps.
 *  - Allocate a new mac (hash) table.
 *  - Add the specified entries to the new table.
 *    (except the ones that are requested to be deleted).
 *  - Add all the other entries from the old mac table.
 *  - If there is a failure, free the new table and return.
 *  - Switch to the new table.
 *  - Free the old table and return.
 *
 * The function also expects the requested range to be valid.
 */
int opa_vnic_update_mac_tbl(struct opa_vnic_adapter *adapter,
			    struct opa_veswport_mactable *tbl)
{
	struct opa_vnic_mac_tbl_node *node, *new_node;
	struct hlist_head *new_mactbl, *old_mactbl;
	int i, bkt, rc = 0;
	u8 key;
	u16 loffset, lnum_entries;

	mutex_lock(&adapter->mactbl_lock);
	/* allocate new mac table */
	new_mactbl = opa_vnic_alloc_mac_tbl();
	if (IS_ERR(new_mactbl)) {
		mutex_unlock(&adapter->mactbl_lock);
		return PTR_ERR(new_mactbl);
	}

	loffset = be16_to_cpu(tbl->offset);
	lnum_entries = be16_to_cpu(tbl->num_entries);

	/* add updated entries to the new mac table */
	for (i = 0; i < lnum_entries; i++) {
		struct __opa_vnic_mactable_entry *nentry;
		struct opa_veswport_mactable_entry *entry =
							&tbl->tbl_entries[i];
		u8 *mac_addr = entry->mac_addr;
		u8 empty_mac[ETH_ALEN] = { 0 };

		v_dbg("new mac entry %4d: %02x:%02x:%02x:%02x:%02x:%02x %x\n",
		      loffset + i, mac_addr[0], mac_addr[1], mac_addr[2],
		      mac_addr[3], mac_addr[4], mac_addr[5],
		      entry->dlid_sd);

		/* if the entry is being removed, do not add it */
		if (!memcmp(mac_addr, empty_mac, ARRAY_SIZE(empty_mac)))
			continue;

		node = kzalloc(sizeof(*node), GFP_KERNEL);
		if (!node) {
			rc = -ENOMEM;
			goto updt_done;
		}

		node->index = loffset + i;
		nentry = &node->entry;
		memcpy(nentry->mac_addr, entry->mac_addr,
		       ARRAY_SIZE(nentry->mac_addr));
		memcpy(nentry->mac_addr_mask, entry->mac_addr_mask,
		       ARRAY_SIZE(nentry->mac_addr_mask));
		nentry->dlid_sd = be32_to_cpu(entry->dlid_sd);
		key = node->entry.mac_addr[OPA_VNIC_MAC_HASH_IDX];
		vnic_hash_add(new_mactbl, &node->hlist, key);
	}

	/* add other entries from current mac table to new mac table */
	old_mactbl = rcu_access_pointer(adapter->mactbl);
	if (!old_mactbl)
		goto switch_tbl;

	vnic_hash_for_each(old_mactbl, bkt, node, hlist) {
		if ((node->index >= loffset) &&
		    (node->index < (loffset + lnum_entries)))
			continue;

		new_node = kzalloc(sizeof(*new_node), GFP_KERNEL);
		if (!new_node) {
			rc = -ENOMEM;
			goto updt_done;
		}

		new_node->index = node->index;
		memcpy(&new_node->entry, &node->entry, sizeof(node->entry));
		key = new_node->entry.mac_addr[OPA_VNIC_MAC_HASH_IDX];
		vnic_hash_add(new_mactbl, &new_node->hlist, key);
	}

switch_tbl:
	/* switch to new table */
	rcu_assign_pointer(adapter->mactbl, new_mactbl);
	synchronize_rcu();

	adapter->info.vport.mac_tbl_digest = be32_to_cpu(tbl->mac_tbl_digest);
updt_done:
	/* upon failure, free the new table; otherwise, free the old table */
	if (rc)
		opa_vnic_free_mac_tbl(new_mactbl);
	else
		opa_vnic_free_mac_tbl(old_mactbl);

	mutex_unlock(&adapter->mactbl_lock);
	return rc;
}

/* opa_vnic_chk_mac_tbl - check mac table for dlid */
static uint32_t opa_vnic_chk_mac_tbl(struct opa_vnic_adapter *adapter,
				     struct ethhdr *mac_hdr)
{
	struct opa_vnic_mac_tbl_node *node;
	struct hlist_head *mactbl;
	u32 dlid = 0;
	u8 key;

	rcu_read_lock();
	mactbl = rcu_dereference(adapter->mactbl);
	if (unlikely(!mactbl))
		goto chk_done;

	key = mac_hdr->h_dest[OPA_VNIC_MAC_HASH_IDX];
	vnic_hash_for_each_possible(mactbl, node, hlist, key) {
		struct __opa_vnic_mactable_entry *entry = &node->entry;

		/* if related to source mac, skip */
		if (unlikely(OPA_VNIC_DLID_SD_IS_SRC_MAC(entry->dlid_sd)))
			continue;

		if (!memcmp(node->entry.mac_addr, mac_hdr->h_dest,
			    ARRAY_SIZE(node->entry.mac_addr))) {
			/* mac address found */
			dlid = OPA_VNIC_DLID_SD_GET_DLID(node->entry.dlid_sd);
			break;
		}
	}

chk_done:
	rcu_read_unlock();
	return dlid;
}

/* opa_vnic_get_dlid - find and return the DLID */
static uint32_t opa_vnic_get_dlid(struct opa_vnic_adapter *adapter,
				  struct sk_buff *skb, u8 def_port)
{
	struct __opa_veswport_info *info = &adapter->info;
	struct ethhdr *mac_hdr = (struct ethhdr *)skb_mac_header(skb);
	u32 dlid;

	dlid = opa_vnic_chk_mac_tbl(adapter, mac_hdr);
	if (dlid)
		return dlid;

	if (is_multicast_ether_addr(mac_hdr->h_dest)) {
		dlid = info->vesw.u_mcast_dlid;
	} else {
		if (is_local_ether_addr(mac_hdr->h_dest)) {
			dlid = ((uint32_t)mac_hdr->h_dest[5] << 16) |
				((uint32_t)mac_hdr->h_dest[4] << 8)  |
				mac_hdr->h_dest[3];
			if (unlikely(!dlid))
				v_warn("Null dlid in MAC address\n");
		} else if (def_port != OPA_VNIC_INVALID_PORT) {
			dlid = info->vesw.u_ucast_dlid[def_port];
		}
	}

	return dlid;
}

/* opa_vnic_get_sc - return the service class */
static u8 opa_vnic_get_sc(struct __opa_veswport_info *info,
			  struct sk_buff *skb)
{
	struct ethhdr *mac_hdr = (struct ethhdr *)skb_mac_header(skb);
	u16 vlan_tci;
	u8 sc;

	if (!__vlan_get_tag(skb, &vlan_tci)) {
		u8 pcp = OPA_VNIC_VLAN_PCP(vlan_tci);

		if (is_multicast_ether_addr(mac_hdr->h_dest))
			sc = info->vport.pcp_to_sc_mc[pcp];
		else
			sc = info->vport.pcp_to_sc_uc[pcp];
	} else {
		if (is_multicast_ether_addr(mac_hdr->h_dest))
			sc = info->vport.non_vlan_sc_mc;
		else
			sc = info->vport.non_vlan_sc_uc;
	}

	return sc;
}

u8 opa_vnic_get_vl(struct opa_vnic_adapter *adapter, struct sk_buff *skb)
{
	struct ethhdr *mac_hdr = (struct ethhdr *)skb_mac_header(skb);
	struct __opa_veswport_info *info = &adapter->info;
	u8 vl;

	if (skb_vlan_tag_present(skb)) {
		u8 pcp = skb_vlan_tag_get(skb) >> VLAN_PRIO_SHIFT;

		if (is_multicast_ether_addr(mac_hdr->h_dest))
			vl = info->vport.pcp_to_vl_mc[pcp];
		else
			vl = info->vport.pcp_to_vl_uc[pcp];
	} else {
		if (is_multicast_ether_addr(mac_hdr->h_dest))
			vl = info->vport.non_vlan_vl_mc;
		else
			vl = info->vport.non_vlan_vl_uc;
	}

	return vl;
}

/* opa_vnic_get_rc - return the routing control */
static u8 opa_vnic_get_rc(struct __opa_veswport_info *info,
			  struct sk_buff *skb)
{
	u8 proto, rout_ctrl;

	switch (vlan_get_protocol(skb)) {
	case htons(ETH_P_IPV6):
		proto = ipv6_hdr(skb)->nexthdr;
		if (proto == IPPROTO_TCP)
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc,
							  IPV6_TCP);
		else if (proto == IPPROTO_UDP)
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc,
							  IPV6_UDP);
		else
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc, IPV6);
		break;
	case htons(ETH_P_IP):
		proto = ip_hdr(skb)->protocol;
		if (proto == IPPROTO_TCP)
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc,
							  IPV4_TCP);
		else if (proto == IPPROTO_UDP)
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc,
							  IPV4_UDP);
		else
			rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc, IPV4);
		break;
	default:
		rout_ctrl = OPA_VNIC_ENCAP_RC_EXT(info->vesw.rc, DEFAULT);
	}

	return rout_ctrl;
}

/* opa_vnic_calc_entropy - calculate the packet entropy */
u8 opa_vnic_calc_entropy(struct opa_vnic_adapter *adapter, struct sk_buff *skb)
{
	u16 hash16;

	/*
	 * Get flow based 16-bit hash and then XOR the upper and lower bytes
	 * to get the entropy.
	 * __skb_tx_hash limits qcount to 16 bits. Hence, get 15-bit hash.
	 */
	hash16 = __skb_tx_hash(adapter->netdev, skb, BIT(15));
	return (u8)((hash16 >> 8) ^ (hash16 & 0xff));
}

/* opa_vnic_get_def_port - get default port based on entropy */
static inline u8 opa_vnic_get_def_port(struct opa_vnic_adapter *adapter,
				       u8 entropy)
{
	u8 flow_id;

	/* Add the upper and lower 4-bits of entropy to get the flow id */
	flow_id = ((entropy & 0xf) + (entropy >> 4));
	return adapter->flow_tbl[flow_id & (OPA_VNIC_FLOW_TBL_SIZE - 1)];
}

/* Calculate packet length including OPA header, crc and padding */
static inline int opa_vnic_wire_length(struct sk_buff *skb)
{
	u32 pad_len;

	/* padding for 8 bytes size alignment */
	pad_len = -(skb->len + OPA_VNIC_ICRC_TAIL_LEN) & 0x7;
	pad_len += OPA_VNIC_ICRC_TAIL_LEN;

	return (skb->len + pad_len) >> 3;
}

/* opa_vnic_encap_skb - encapsulate skb packet with OPA header and meta data */
void opa_vnic_encap_skb(struct opa_vnic_adapter *adapter, struct sk_buff *skb)
{
	struct __opa_veswport_info *info = &adapter->info;
	struct opa_vnic_skb_mdata *mdata;
	u8 def_port, sc, rc, entropy, *hdr;
	u16 len, l4_hdr;
	u32 dlid;

	hdr = skb_push(skb, OPA_VNIC_HDR_LEN);

	entropy = opa_vnic_calc_entropy(adapter, skb);
	def_port = opa_vnic_get_def_port(adapter, entropy);
	len = opa_vnic_wire_length(skb);
	dlid = opa_vnic_get_dlid(adapter, skb, def_port);
	sc = opa_vnic_get_sc(info, skb);
	rc = opa_vnic_get_rc(info, skb);
	l4_hdr = info->vesw.vesw_id;

	mdata = skb_push(skb, sizeof(*mdata));
	mdata->vl = opa_vnic_get_vl(adapter, skb);
	mdata->entropy = entropy;
	mdata->flags = 0;
	if (unlikely(!dlid)) {
		mdata->flags = OPA_VNIC_SKB_MDATA_ENCAP_ERR;
		return;
	}

	opa_vnic_make_header(hdr, info->vport.encap_slid, dlid, len,
			     info->vesw.pkey, entropy, sc, rc,
			     OPA_VNIC_L4_ETHR, l4_hdr);
}