/*
 * 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) {
                        if (def_port < OPA_VESW_MAX_NUM_DEF_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 sk_buff *skb)
{
        u32 hash = skb_get_hash(skb);

        /* store XOR of all bytes in lower 8 bits */
        hash ^= hash >> 8;
        hash ^= hash >> 16;

        /* return lower 8 bits as entropy */
        return (u8)(hash & 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(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);
}