/* SPDX-License-Identifier: BSD-3-Clause */
/*  Copyright (c) 2024, Intel Corporation
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/**
 * @file ice_common_txrx.h
 * @brief common Tx/Rx utility functions
 *
 * Contains common utility functions for the Tx/Rx hot path.
 *
 * The functions do depend on the if_pkt_info_t structure. A suitable
 * implementation of this structure must be provided if these functions are to
 * be used without the iflib networking stack.
 */

#ifndef _ICE_COMMON_TXRX_H_
#define _ICE_COMMON_TXRX_H_

#include <netinet/udp.h>
#include <netinet/sctp.h>

/**
 * ice_tso_detect_sparse - detect TSO packets with too many segments
 * @pi: packet information
 *
 * Hardware only transmits packets with a maximum of 8 descriptors. For TSO
 * packets, hardware needs to be able to build the split packets using 8 or
 * fewer descriptors. Additionally, the header must be contained within at
 * most 3 descriptors.
 *
 * To verify this, we walk the headers to find out how many descriptors the
 * headers require (usually 1). Then we ensure that, for each TSO segment, its
 * data plus the headers are contained within 8 or fewer descriptors.
 */
static inline int
ice_tso_detect_sparse(if_pkt_info_t pi)
{
        int count, curseg, i, hlen, segsz, seglen, tsolen, hdrs, maxsegs;
        bus_dma_segment_t *segs = pi->ipi_segs;
        int nsegs = pi->ipi_nsegs;

        curseg = hdrs = 0;

        hlen = pi->ipi_ehdrlen + pi->ipi_ip_hlen + pi->ipi_tcp_hlen;
        tsolen = pi->ipi_len - hlen;

        /* First, count the number of descriptors for the header.
         * Additionally, make sure it does not span more than 3 segments.
         */
        i = 0;
        curseg = segs[0].ds_len;
        while (hlen > 0) {
                hdrs++;
                if (hdrs > ICE_MAX_TSO_HDR_SEGS)
                        return (1);
                if (curseg == 0) {
                        i++;
                        if (__predict_false(i == nsegs))
                                return (1);

                        curseg = segs[i].ds_len;
                }
                seglen = min(curseg, hlen);
                curseg -= seglen;
                hlen -= seglen;
        }

        maxsegs = ICE_MAX_TX_SEGS - hdrs;

        /* We must count the headers, in order to verify that they take up
         * 3 or fewer descriptors. However, we don't need to check the data
         * if the total segments is small.
         */
        if (nsegs <= maxsegs)
                return (0);

        count = 0;

        /* Now check the data to make sure that each TSO segment is made up of
         * no more than maxsegs descriptors. This ensures that hardware will
         * be capable of performing TSO offload.
         */
        while (tsolen > 0) {
                segsz = pi->ipi_tso_segsz;
                while (segsz > 0 && tsolen != 0) {
                        count++;
                        if (count > maxsegs) {
                                return (1);
                        }
                        if (curseg == 0) {
                                i++;
                                if (__predict_false(i == nsegs)) {
                                        return (1);
                                }
                                curseg = segs[i].ds_len;
                        }
                        seglen = min(curseg, segsz);
                        segsz -= seglen;
                        curseg -= seglen;
                        tsolen -= seglen;
                }
                count = 0;
        }

        return (0);
}

/**
 * ice_tso_setup - Setup a context descriptor to prepare for a TSO packet
 * @txq: the Tx queue to use
 * @pi: the packet info to prepare for
 *
 * Setup a context descriptor in preparation for sending a Tx packet that
 * requires the TSO offload. Returns the index of the descriptor to use when
 * encapsulating the Tx packet data into descriptors.
 */
static inline int
ice_tso_setup(struct ice_tx_queue *txq, if_pkt_info_t pi)
{
        struct ice_tx_ctx_desc          *txd;
        u32                             cmd, mss, type, tsolen;
        int                             idx;
        u64                             type_cmd_tso_mss;

        idx = pi->ipi_pidx;
        txd = (struct ice_tx_ctx_desc *)&txq->tx_base[idx];
        tsolen = pi->ipi_len - (pi->ipi_ehdrlen + pi->ipi_ip_hlen + pi->ipi_tcp_hlen);

        type = ICE_TX_DESC_DTYPE_CTX;
        cmd = ICE_TX_CTX_DESC_TSO;
        /* TSO MSS must not be less than 64 */
        if (pi->ipi_tso_segsz < ICE_MIN_TSO_MSS) {
                txq->stats.mss_too_small++;
                pi->ipi_tso_segsz = ICE_MIN_TSO_MSS;
        }
        mss = pi->ipi_tso_segsz;

        type_cmd_tso_mss = ((u64)type << ICE_TXD_CTX_QW1_DTYPE_S) |
            ((u64)cmd << ICE_TXD_CTX_QW1_CMD_S) |
            ((u64)tsolen << ICE_TXD_CTX_QW1_TSO_LEN_S) |
            ((u64)mss << ICE_TXD_CTX_QW1_MSS_S);
        txd->qw1 = htole64(type_cmd_tso_mss);

        txd->tunneling_params = htole32(0);
        txq->stats.tso++;

        return ((idx + 1) & (txq->desc_count-1));
}

/**
 * ice_tx_setup_offload - Setup register values for performing a Tx offload
 * @txq: The Tx queue, used to track checksum offload stats
 * @pi: the packet info to program for
 * @cmd: the cmd register value to update
 * @off: the off register value to update
 *
 * Based on the packet info provided, update the cmd and off values for
 * enabling Tx offloads. This depends on the packet type and which offloads
 * have been requested.
 *
 * We also track the total number of times that we've requested hardware
 * offload a particular type of checksum for debugging purposes.
 */
static inline void
ice_tx_setup_offload(struct ice_tx_queue *txq, if_pkt_info_t pi, u32 *cmd, u32 *off)
{
        u32 remaining_csum_flags = pi->ipi_csum_flags;

        switch (pi->ipi_etype) {
#ifdef INET
                case ETHERTYPE_IP:
                        if (pi->ipi_csum_flags & ICE_CSUM_IP) {
                                *cmd |= ICE_TX_DESC_CMD_IIPT_IPV4_CSUM;
                                txq->stats.cso[ICE_CSO_STAT_TX_IP4]++;
                                remaining_csum_flags &= ~CSUM_IP;
                        } else
                                *cmd |= ICE_TX_DESC_CMD_IIPT_IPV4;
                        break;
#endif
#ifdef INET6
                case ETHERTYPE_IPV6:
                        *cmd |= ICE_TX_DESC_CMD_IIPT_IPV6;
                        /*
                         * This indicates that the IIPT flag was set to the IPV6 value;
                         * there's no checksum for IPv6 packets.
                         */
                        txq->stats.cso[ICE_CSO_STAT_TX_IP6]++;
                        break;
#endif
                default:
                        txq->stats.cso[ICE_CSO_STAT_TX_L3_ERR]++;
                        break;
        }

        *off |= (pi->ipi_ehdrlen >> 1) << ICE_TX_DESC_LEN_MACLEN_S;
        *off |= (pi->ipi_ip_hlen >> 2) << ICE_TX_DESC_LEN_IPLEN_S;

        if (!(remaining_csum_flags & ~ICE_RX_CSUM_FLAGS))
                return;

        switch (pi->ipi_ipproto) {
                case IPPROTO_TCP:
                        if (pi->ipi_csum_flags & ICE_CSUM_TCP) {
                                *cmd |= ICE_TX_DESC_CMD_L4T_EOFT_TCP;
                                *off |= (pi->ipi_tcp_hlen >> 2) <<
                                    ICE_TX_DESC_LEN_L4_LEN_S;
                                txq->stats.cso[ICE_CSO_STAT_TX_TCP]++;
                        }
                        break;
                case IPPROTO_UDP:
                        if (pi->ipi_csum_flags & ICE_CSUM_UDP) {
                                *cmd |= ICE_TX_DESC_CMD_L4T_EOFT_UDP;
                                *off |= (sizeof(struct udphdr) >> 2) <<
                                    ICE_TX_DESC_LEN_L4_LEN_S;
                                txq->stats.cso[ICE_CSO_STAT_TX_UDP]++;
                        }
                        break;
                case IPPROTO_SCTP:
                        if (pi->ipi_csum_flags & ICE_CSUM_SCTP) {
                                *cmd |= ICE_TX_DESC_CMD_L4T_EOFT_SCTP;
                                *off |= (sizeof(struct sctphdr) >> 2) <<
                                    ICE_TX_DESC_LEN_L4_LEN_S;
                                txq->stats.cso[ICE_CSO_STAT_TX_SCTP]++;
                        }
                        break;
                default:
                        txq->stats.cso[ICE_CSO_STAT_TX_L4_ERR]++;
                        break;
        }
}

/**
 * ice_rx_checksum - verify hardware checksum is valid or not
 * @rxq: the Rx queue structure
 * @flags: checksum flags to update
 * @data: checksum data to update
 * @status0: descriptor status data
 * @ptype: packet type
 *
 * Determine whether the hardware indicated that the Rx checksum is valid. If
 * so, update the checksum flags and data, informing the stack of the status
 * of the checksum so that it does not spend time verifying it manually.
 */
static void
ice_rx_checksum(struct ice_rx_queue *rxq, uint32_t *flags, uint32_t *data,
                u16 status0, u16 ptype)
{
        const u16 l3_error = (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S) |
                              BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S));
        const u16 l4_error = (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S) |
                              BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EUDPE_S));
        const u16 xsum_errors = (l3_error | l4_error |
                                 BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S));
        struct ice_rx_ptype_decoded decoded;
        bool is_ipv4, is_ipv6;

        /* No L3 or L4 checksum was calculated */
        if (!(status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S))) {
                return;
        }

        decoded = ice_decode_rx_desc_ptype(ptype);
        *flags = 0;

        if (!(decoded.known && decoded.outer_ip))
                return;

        is_ipv4 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) &&
            (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV4);
        is_ipv6 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) &&
            (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV6);

        /* No checksum errors were reported */
        if (!(status0 & xsum_errors)) {
                if (is_ipv4)
                        *flags |= CSUM_L3_CALC | CSUM_L3_VALID;

                switch (decoded.inner_prot) {
                case ICE_RX_PTYPE_INNER_PROT_TCP:
                case ICE_RX_PTYPE_INNER_PROT_UDP:
                case ICE_RX_PTYPE_INNER_PROT_SCTP:
                        *flags |= CSUM_L4_CALC | CSUM_L4_VALID;
                        *data |= htons(0xffff);
                        break;
                default:
                        break;
                }

                return;
        }

        /*
         * Certain IPv6 extension headers impact the validity of L4 checksums.
         * If one of these headers exist, hardware will set the IPV6EXADD bit
         * in the descriptor. If the bit is set then pretend like hardware
         * didn't checksum this packet.
         */
        if (is_ipv6 && (status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S))) {
                rxq->stats.cso[ICE_CSO_STAT_RX_IP6_ERR]++;
                return;
        }

        /*
         * At this point, status0 must have at least one of the l3_error or
         * l4_error bits set.
         */

        if (status0 & l3_error) {
                if (is_ipv4) {
                        rxq->stats.cso[ICE_CSO_STAT_RX_IP4_ERR]++;
                        *flags |= CSUM_L3_CALC;
                } else {
                        /* Hardware indicated L3 error but this isn't IPv4? */
                        rxq->stats.cso[ICE_CSO_STAT_RX_L3_ERR]++;
                }
                /* don't bother reporting L4 errors if we got an L3 error */
                return;
        } else if (is_ipv4) {
                *flags |= CSUM_L3_CALC | CSUM_L3_VALID;
        }

        if (status0 & l4_error) {
                switch (decoded.inner_prot) {
                case ICE_RX_PTYPE_INNER_PROT_TCP:
                        rxq->stats.cso[ICE_CSO_STAT_RX_TCP_ERR]++;
                        *flags |= CSUM_L4_CALC;
                        break;
                case ICE_RX_PTYPE_INNER_PROT_UDP:
                        rxq->stats.cso[ICE_CSO_STAT_RX_UDP_ERR]++;
                        *flags |= CSUM_L4_CALC;
                        break;
                case ICE_RX_PTYPE_INNER_PROT_SCTP:
                        rxq->stats.cso[ICE_CSO_STAT_RX_SCTP_ERR]++;
                        *flags |= CSUM_L4_CALC;
                        break;
                default:
                        /*
                         * Hardware indicated L4 error, but this isn't one of
                         * the expected protocols.
                         */
                        rxq->stats.cso[ICE_CSO_STAT_RX_L4_ERR]++;
                }
        }
}

/**
 * ice_ptype_to_hash - Convert packet type to a hash value
 * @ptype: the packet type to convert
 *
 * Given the packet type, convert to a suitable hashtype to report to the
 * upper stack via the iri_rsstype value of the if_rxd_info_t structure.
 *
 * If the hash type is unknown we'll report M_HASHTYPE_OPAQUE.
 */
static inline int
ice_ptype_to_hash(u16 ptype)
{
        struct ice_rx_ptype_decoded decoded;

        if (ptype >= ARRAY_SIZE(ice_ptype_lkup))
                return M_HASHTYPE_OPAQUE;

        decoded = ice_decode_rx_desc_ptype(ptype);

        if (!decoded.known)
                return M_HASHTYPE_OPAQUE;

        if (decoded.outer_ip == ICE_RX_PTYPE_OUTER_L2)
                return M_HASHTYPE_OPAQUE;

        /* Note: anything that gets to this point is IP */
        if (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV6) {
                switch (decoded.inner_prot) {
                case ICE_RX_PTYPE_INNER_PROT_TCP:
                        return M_HASHTYPE_RSS_TCP_IPV6;
                case ICE_RX_PTYPE_INNER_PROT_UDP:
                        return M_HASHTYPE_RSS_UDP_IPV6;
                default:
                        return M_HASHTYPE_RSS_IPV6;
                }
        }
        if (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV4) {
                switch (decoded.inner_prot) {
                case ICE_RX_PTYPE_INNER_PROT_TCP:
                        return M_HASHTYPE_RSS_TCP_IPV4;
                case ICE_RX_PTYPE_INNER_PROT_UDP:
                        return M_HASHTYPE_RSS_UDP_IPV4;
                default:
                        return M_HASHTYPE_RSS_IPV4;
                }
        }

        /* We should never get here!! */
        return M_HASHTYPE_OPAQUE;
}
#endif