/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2020 Inspur Corporation
 */

#include <rte_malloc.h>
#include <rte_mbuf.h>
#include <rte_cycles.h>
#include <rte_ethdev.h>
#include <rte_udp.h>

#include "gro_vxlan_udp4.h"

void *
gro_vxlan_udp4_tbl_create(uint16_t socket_id,
                uint16_t max_flow_num,
                uint16_t max_item_per_flow)
{
        struct gro_vxlan_udp4_tbl *tbl;
        size_t size;
        uint32_t entries_num, i;

        entries_num = max_flow_num * max_item_per_flow;
        entries_num = RTE_MIN(entries_num, GRO_VXLAN_UDP4_TBL_MAX_ITEM_NUM);

        if (entries_num == 0)
                return NULL;

        tbl = rte_zmalloc_socket(__func__,
                        sizeof(struct gro_vxlan_udp4_tbl),
                        RTE_CACHE_LINE_SIZE,
                        socket_id);
        if (tbl == NULL)
                return NULL;

        size = sizeof(struct gro_vxlan_udp4_item) * entries_num;
        tbl->items = rte_zmalloc_socket(__func__,
                        size,
                        RTE_CACHE_LINE_SIZE,
                        socket_id);
        if (tbl->items == NULL) {
                rte_free(tbl);
                return NULL;
        }
        tbl->max_item_num = entries_num;

        size = sizeof(struct gro_vxlan_udp4_flow) * entries_num;
        tbl->flows = rte_zmalloc_socket(__func__,
                        size,
                        RTE_CACHE_LINE_SIZE,
                        socket_id);
        if (tbl->flows == NULL) {
                rte_free(tbl->items);
                rte_free(tbl);
                return NULL;
        }

        for (i = 0; i < entries_num; i++)
                tbl->flows[i].start_index = INVALID_ARRAY_INDEX;
        tbl->max_flow_num = entries_num;

        return tbl;
}

void
gro_vxlan_udp4_tbl_destroy(void *tbl)
{
        struct gro_vxlan_udp4_tbl *vxlan_tbl = tbl;

        if (vxlan_tbl) {
                rte_free(vxlan_tbl->items);
                rte_free(vxlan_tbl->flows);
        }
        rte_free(vxlan_tbl);
}

static inline uint32_t
find_an_empty_item(struct gro_vxlan_udp4_tbl *tbl)
{
        uint32_t max_item_num = tbl->max_item_num, i;

        for (i = 0; i < max_item_num; i++)
                if (tbl->items[i].inner_item.firstseg == NULL)
                        return i;
        return INVALID_ARRAY_INDEX;
}

static inline uint32_t
find_an_empty_flow(struct gro_vxlan_udp4_tbl *tbl)
{
        uint32_t max_flow_num = tbl->max_flow_num, i;

        for (i = 0; i < max_flow_num; i++)
                if (tbl->flows[i].start_index == INVALID_ARRAY_INDEX)
                        return i;
        return INVALID_ARRAY_INDEX;
}

static inline uint32_t
insert_new_item(struct gro_vxlan_udp4_tbl *tbl,
                struct rte_mbuf *pkt,
                uint64_t start_time,
                uint32_t prev_idx,
                uint16_t frag_offset,
                uint8_t is_last_frag)
{
        uint32_t item_idx;

        item_idx = find_an_empty_item(tbl);
        if (unlikely(item_idx == INVALID_ARRAY_INDEX))
                return INVALID_ARRAY_INDEX;

        tbl->items[item_idx].inner_item.firstseg = pkt;
        tbl->items[item_idx].inner_item.lastseg = rte_pktmbuf_lastseg(pkt);
        tbl->items[item_idx].inner_item.start_time = start_time;
        tbl->items[item_idx].inner_item.next_pkt_idx = INVALID_ARRAY_INDEX;
        tbl->items[item_idx].inner_item.frag_offset = frag_offset;
        tbl->items[item_idx].inner_item.is_last_frag = is_last_frag;
        tbl->items[item_idx].inner_item.nb_merged = 1;
        tbl->item_num++;

        /* If the previous packet exists, chain the new one with it. */
        if (prev_idx != INVALID_ARRAY_INDEX) {
                tbl->items[item_idx].inner_item.next_pkt_idx =
                        tbl->items[prev_idx].inner_item.next_pkt_idx;
                tbl->items[prev_idx].inner_item.next_pkt_idx = item_idx;
        }

        return item_idx;
}

static inline uint32_t
delete_item(struct gro_vxlan_udp4_tbl *tbl,
                uint32_t item_idx,
                uint32_t prev_item_idx)
{
        uint32_t next_idx = tbl->items[item_idx].inner_item.next_pkt_idx;

        /* NULL indicates an empty item. */
        tbl->items[item_idx].inner_item.firstseg = NULL;
        tbl->item_num--;
        if (prev_item_idx != INVALID_ARRAY_INDEX)
                tbl->items[prev_item_idx].inner_item.next_pkt_idx = next_idx;

        return next_idx;
}

static inline uint32_t
insert_new_flow(struct gro_vxlan_udp4_tbl *tbl,
                struct vxlan_udp4_flow_key *src,
                uint32_t item_idx)
{
        struct vxlan_udp4_flow_key *dst;
        uint32_t flow_idx;

        flow_idx = find_an_empty_flow(tbl);
        if (unlikely(flow_idx == INVALID_ARRAY_INDEX))
                return INVALID_ARRAY_INDEX;

        dst = &(tbl->flows[flow_idx].key);

        rte_ether_addr_copy(&(src->inner_key.eth_saddr),
                        &(dst->inner_key.eth_saddr));
        rte_ether_addr_copy(&(src->inner_key.eth_daddr),
                        &(dst->inner_key.eth_daddr));
        dst->inner_key.ip_src_addr = src->inner_key.ip_src_addr;
        dst->inner_key.ip_dst_addr = src->inner_key.ip_dst_addr;
        dst->inner_key.ip_id = src->inner_key.ip_id;

        dst->vxlan_hdr.vx_flags = src->vxlan_hdr.vx_flags;
        dst->vxlan_hdr.vx_vni = src->vxlan_hdr.vx_vni;
        rte_ether_addr_copy(&(src->outer_eth_saddr), &(dst->outer_eth_saddr));
        rte_ether_addr_copy(&(src->outer_eth_daddr), &(dst->outer_eth_daddr));
        dst->outer_ip_src_addr = src->outer_ip_src_addr;
        dst->outer_ip_dst_addr = src->outer_ip_dst_addr;
        dst->outer_dst_port = src->outer_dst_port;

        tbl->flows[flow_idx].start_index = item_idx;
        tbl->flow_num++;

        return flow_idx;
}

static inline int
is_same_vxlan_udp4_flow(struct vxlan_udp4_flow_key k1,
                struct vxlan_udp4_flow_key k2)
{
        /* For VxLAN packet, outer udp src port is calculated from
         * inner packet RSS hash, udp src port of the first UDP
         * fragment is different from one of other UDP fragments
         * even if they are same flow, so we have to skip outer udp
         * src port comparison here.
         */
        return (rte_is_same_ether_addr(&k1.outer_eth_saddr,
                                        &k2.outer_eth_saddr) &&
                        rte_is_same_ether_addr(&k1.outer_eth_daddr,
                                &k2.outer_eth_daddr) &&
                        (k1.outer_ip_src_addr == k2.outer_ip_src_addr) &&
                        (k1.outer_ip_dst_addr == k2.outer_ip_dst_addr) &&
                        (k1.outer_dst_port == k2.outer_dst_port) &&
                        (k1.vxlan_hdr.vx_flags == k2.vxlan_hdr.vx_flags) &&
                        (k1.vxlan_hdr.vx_vni == k2.vxlan_hdr.vx_vni) &&
                        is_same_udp4_flow(k1.inner_key, k2.inner_key));
}

static inline int
udp4_check_vxlan_neighbor(struct gro_vxlan_udp4_item *item,
                uint16_t frag_offset,
                uint16_t ip_dl)
{
        struct rte_mbuf *pkt = item->inner_item.firstseg;
        int cmp;
        uint16_t l2_offset;
        int ret = 0;

        /* Note: if outer DF bit is set, i.e outer_is_atomic is 0,
         * we needn't compare outer_ip_id because they are same,
         * for the case outer_is_atomic is 1, we also have no way
         * to compare outer_ip_id because the difference between
         * outer_ip_ids of two received packets isn't always +/-1.
         * So skip outer_ip_id comparison here.
         */

        l2_offset = pkt->outer_l2_len + pkt->outer_l3_len;
        cmp = udp4_check_neighbor(&item->inner_item, frag_offset, ip_dl,
                                        l2_offset);
        if (cmp > 0)
                /* Append the new packet. */
                ret = 1;
        else if (cmp < 0)
                /* Prepend the new packet. */
                ret = -1;

        return ret;
}

static inline int
merge_two_vxlan_udp4_packets(struct gro_vxlan_udp4_item *item,
                struct rte_mbuf *pkt,
                int cmp,
                uint16_t frag_offset,
                uint8_t is_last_frag)
{
        if (merge_two_udp4_packets(&item->inner_item, pkt, cmp, frag_offset,
                                is_last_frag,
                                pkt->outer_l2_len + pkt->outer_l3_len)) {
                return 1;
        }

        return 0;
}

static inline void
update_vxlan_header(struct gro_vxlan_udp4_item *item)
{
        struct rte_ipv4_hdr *ipv4_hdr;
        struct rte_udp_hdr *udp_hdr;
        struct rte_mbuf *pkt = item->inner_item.firstseg;
        uint16_t len;
        uint16_t frag_offset;

        /* Update the outer IPv4 header. */
        len = pkt->pkt_len - pkt->outer_l2_len;
        ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
                        pkt->outer_l2_len);
        ipv4_hdr->total_length = rte_cpu_to_be_16(len);

        /* Update the outer UDP header. */
        len -= pkt->outer_l3_len;
        udp_hdr = (struct rte_udp_hdr *)((char *)ipv4_hdr + pkt->outer_l3_len);
        udp_hdr->dgram_len = rte_cpu_to_be_16(len);

        /* Update the inner IPv4 header. */
        len -= pkt->l2_len;
        ipv4_hdr = (struct rte_ipv4_hdr *)((char *)udp_hdr + pkt->l2_len);
        ipv4_hdr->total_length = rte_cpu_to_be_16(len);

        /* Clear MF bit if it is last fragment */
        if (item->inner_item.is_last_frag) {
                frag_offset = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
                ipv4_hdr->fragment_offset =
                        rte_cpu_to_be_16(frag_offset & ~RTE_IPV4_HDR_MF_FLAG);
        }
}

int32_t
gro_vxlan_udp4_reassemble(struct rte_mbuf *pkt,
                struct gro_vxlan_udp4_tbl *tbl,
                uint64_t start_time)
{
        struct rte_ether_hdr *outer_eth_hdr, *eth_hdr;
        struct rte_ipv4_hdr *outer_ipv4_hdr, *ipv4_hdr;
        struct rte_udp_hdr *udp_hdr;
        struct rte_vxlan_hdr *vxlan_hdr;
        uint16_t frag_offset;
        uint8_t is_last_frag;
        int16_t ip_dl;
        uint16_t ip_id;

        struct vxlan_udp4_flow_key key;
        uint32_t cur_idx, prev_idx, item_idx;
        uint32_t i, max_flow_num, remaining_flow_num;
        int cmp;
        uint16_t hdr_len;
        uint8_t find;

        outer_eth_hdr = rte_pktmbuf_mtod(pkt, struct rte_ether_hdr *);
        outer_ipv4_hdr = (struct rte_ipv4_hdr *)((char *)outer_eth_hdr +
                        pkt->outer_l2_len);

        udp_hdr = (struct rte_udp_hdr *)((char *)outer_ipv4_hdr +
                        pkt->outer_l3_len);
        vxlan_hdr = (struct rte_vxlan_hdr *)((char *)udp_hdr +
                        sizeof(struct rte_udp_hdr));
        eth_hdr = (struct rte_ether_hdr *)((char *)vxlan_hdr +
                        sizeof(struct rte_vxlan_hdr));
        /* l2_len = outer udp hdr len + vxlan hdr len + inner l2 len */
        ipv4_hdr = (struct rte_ipv4_hdr *)((char *)udp_hdr + pkt->l2_len);

        /*
         * Don't process the packet which has non-fragment inner IP.
         */
        if (!is_ipv4_fragment(ipv4_hdr))
                return -1;

        hdr_len = pkt->outer_l2_len + pkt->outer_l3_len + pkt->l2_len +
                pkt->l3_len;
        /*
         * Don't process the packet whose payload length is less than or
         * equal to 0.
         */
        if (pkt->pkt_len <= hdr_len)
                return -1;

        ip_dl = pkt->pkt_len - hdr_len;

        ip_id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
        frag_offset = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
        is_last_frag = ((frag_offset & RTE_IPV4_HDR_MF_FLAG) == 0) ? 1 : 0;
        frag_offset = (uint16_t)(frag_offset & RTE_IPV4_HDR_OFFSET_MASK) << 3;

        rte_ether_addr_copy(&(eth_hdr->s_addr), &(key.inner_key.eth_saddr));
        rte_ether_addr_copy(&(eth_hdr->d_addr), &(key.inner_key.eth_daddr));
        key.inner_key.ip_src_addr = ipv4_hdr->src_addr;
        key.inner_key.ip_dst_addr = ipv4_hdr->dst_addr;
        key.inner_key.ip_id = ip_id;

        key.vxlan_hdr.vx_flags = vxlan_hdr->vx_flags;
        key.vxlan_hdr.vx_vni = vxlan_hdr->vx_vni;
        rte_ether_addr_copy(&(outer_eth_hdr->s_addr), &(key.outer_eth_saddr));
        rte_ether_addr_copy(&(outer_eth_hdr->d_addr), &(key.outer_eth_daddr));
        key.outer_ip_src_addr = outer_ipv4_hdr->src_addr;
        key.outer_ip_dst_addr = outer_ipv4_hdr->dst_addr;
        /* Note: It is unnecessary to save outer_src_port here because it can
         * be different for VxLAN UDP fragments from the same flow.
         */
        key.outer_dst_port = udp_hdr->dst_port;

        /* Search for a matched flow. */
        max_flow_num = tbl->max_flow_num;
        remaining_flow_num = tbl->flow_num;
        find = 0;
        for (i = 0; i < max_flow_num && remaining_flow_num; i++) {
                if (tbl->flows[i].start_index != INVALID_ARRAY_INDEX) {
                        if (is_same_vxlan_udp4_flow(tbl->flows[i].key, key)) {
                                find = 1;
                                break;
                        }
                        remaining_flow_num--;
                }
        }

        /*
         * Can't find a matched flow. Insert a new flow and store the
         * packet into the flow.
         */
        if (find == 0) {
                item_idx = insert_new_item(tbl, pkt, start_time,
                                INVALID_ARRAY_INDEX, frag_offset,
                                is_last_frag);
                if (unlikely(item_idx == INVALID_ARRAY_INDEX))
                        return -1;
                if (insert_new_flow(tbl, &key, item_idx) ==
                                INVALID_ARRAY_INDEX) {
                        /*
                         * Fail to insert a new flow, so
                         * delete the inserted packet.
                         */
                        delete_item(tbl, item_idx, INVALID_ARRAY_INDEX);
                        return -1;
                }
                return 0;
        }

        /* Check all packets in the flow and try to find a neighbor. */
        cur_idx = tbl->flows[i].start_index;
        prev_idx = cur_idx;
        do {
                cmp = udp4_check_vxlan_neighbor(&(tbl->items[cur_idx]),
                                frag_offset, ip_dl);
                if (cmp) {
                        if (merge_two_vxlan_udp4_packets(
                                                &(tbl->items[cur_idx]),
                                                pkt, cmp, frag_offset,
                                                is_last_frag)) {
                                return 1;
                        }
                        /*
                         * Can't merge two packets, as the packet
                         * length will be greater than the max value.
                         * Insert the packet into the flow.
                         */
                        if (insert_new_item(tbl, pkt, start_time, prev_idx,
                                                frag_offset, is_last_frag) ==
                                        INVALID_ARRAY_INDEX)
                                return -1;
                        return 0;
                }

                /* Ensure inserted items are ordered by frag_offset */
                if (frag_offset
                        < tbl->items[cur_idx].inner_item.frag_offset) {
                        break;
                }

                prev_idx = cur_idx;
                cur_idx = tbl->items[cur_idx].inner_item.next_pkt_idx;
        } while (cur_idx != INVALID_ARRAY_INDEX);

        /* Can't find neighbor. Insert the packet into the flow. */
        if (cur_idx == tbl->flows[i].start_index) {
                /* Insert it before the first packet of the flow */
                item_idx = insert_new_item(tbl, pkt, start_time,
                                INVALID_ARRAY_INDEX, frag_offset,
                                is_last_frag);
                if (unlikely(item_idx == INVALID_ARRAY_INDEX))
                        return -1;
                tbl->items[item_idx].inner_item.next_pkt_idx = cur_idx;
                tbl->flows[i].start_index = item_idx;
        } else {
                if (insert_new_item(tbl, pkt, start_time, prev_idx,
                                        frag_offset, is_last_frag
                                        ) == INVALID_ARRAY_INDEX)
                        return -1;
        }

        return 0;
}

static int
gro_vxlan_udp4_merge_items(struct gro_vxlan_udp4_tbl *tbl,
                           uint32_t start_idx)
{
        uint16_t frag_offset;
        uint8_t is_last_frag;
        int16_t ip_dl;
        struct rte_mbuf *pkt;
        int cmp;
        uint32_t item_idx;
        uint16_t hdr_len;

        item_idx = tbl->items[start_idx].inner_item.next_pkt_idx;
        while (item_idx != INVALID_ARRAY_INDEX) {
                pkt = tbl->items[item_idx].inner_item.firstseg;
                hdr_len = pkt->outer_l2_len + pkt->outer_l3_len + pkt->l2_len +
                        pkt->l3_len;
                ip_dl = pkt->pkt_len - hdr_len;
                frag_offset = tbl->items[item_idx].inner_item.frag_offset;
                is_last_frag = tbl->items[item_idx].inner_item.is_last_frag;
                cmp = udp4_check_vxlan_neighbor(&(tbl->items[start_idx]),
                                        frag_offset, ip_dl);
                if (cmp) {
                        if (merge_two_vxlan_udp4_packets(
                                        &(tbl->items[start_idx]),
                                        pkt, cmp, frag_offset,
                                        is_last_frag)) {
                                item_idx = delete_item(tbl, item_idx,
                                                        INVALID_ARRAY_INDEX);
                                tbl->items[start_idx].inner_item.next_pkt_idx
                                        = item_idx;
                        } else
                                return 0;
                } else
                        return 0;
        }

        return 0;
}

uint16_t
gro_vxlan_udp4_tbl_timeout_flush(struct gro_vxlan_udp4_tbl *tbl,
                uint64_t flush_timestamp,
                struct rte_mbuf **out,
                uint16_t nb_out)
{
        uint16_t k = 0;
        uint32_t i, j;
        uint32_t max_flow_num = tbl->max_flow_num;

        for (i = 0; i < max_flow_num; i++) {
                if (unlikely(tbl->flow_num == 0))
                        return k;

                j = tbl->flows[i].start_index;
                while (j != INVALID_ARRAY_INDEX) {
                        if (tbl->items[j].inner_item.start_time <=
                                        flush_timestamp) {
                                gro_vxlan_udp4_merge_items(tbl, j);
                                out[k++] = tbl->items[j].inner_item.firstseg;
                                if (tbl->items[j].inner_item.nb_merged > 1)
                                        update_vxlan_header(&(tbl->items[j]));
                                /*
                                 * Delete the item and get the next packet
                                 * index.
                                 */
                                j = delete_item(tbl, j, INVALID_ARRAY_INDEX);
                                tbl->flows[i].start_index = j;
                                if (j == INVALID_ARRAY_INDEX)
                                        tbl->flow_num--;

                                if (unlikely(k == nb_out))
                                        return k;
                        } else
                                /*
                                 * Flushing packets does not strictly follow
                                 * timestamp. It does not flush left packets of
                                 * the flow this time once it finds one item
                                 * whose start_time is greater than
                                 * flush_timestamp. So go to check other flows.
                                 */
                                break;
                }
        }
        return k;
}

uint32_t
gro_vxlan_udp4_tbl_pkt_count(void *tbl)
{
        struct gro_vxlan_udp4_tbl *gro_tbl = tbl;

        if (gro_tbl)
                return gro_tbl->item_num;

        return 0;
}