/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006, Myricom Inc.
 * Copyright (c) 2008, Intel Corporation.
 * Copyright (c) 2016-2021 Mellanox Technologies.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#ifndef _TCP_LRO_H_
#define _TCP_LRO_H_

#include <sys/time.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <netinet/in.h>

#ifndef TCP_LRO_ENTRIES
/* Define default number of LRO entries per RX queue */
#define TCP_LRO_ENTRIES 8
#endif

/*
 * Flags for ACK entry for compression
 * the bottom 12 bits has the th_x2|th_flags.
 * LRO itself adds only the TSTMP flags
 * to indicate if either of the types
 * of timestamps are filled and the
 * HAS_TSTMP option to indicate if the
 * TCP timestamp option is valid.
 *
 * The other 1 flag bits are for processing
 * by a stack.
 *
 */
#define TSTMP_LRO               0x1000
#define TSTMP_HDWR              0x2000
#define HAS_TSTMP               0x4000
/*
 * Default number of interrupts on the same cpu in a row
 * that will cause us to declare a "affinity cpu".
 */
#define TCP_LRO_CPU_DECLARATION_THRESH 50

struct inpcb;

/* Precompute the LRO_RAW_ADDRESS_MAX value: */
#define LRO_RAW_ADDRESS_MAX \
        howmany(12 + 2 * sizeof(struct in6_addr), sizeof(u_long))

union lro_address {
        u_long raw[LRO_RAW_ADDRESS_MAX];
        struct {
                uint8_t lro_type;       /* internal */
#define LRO_TYPE_NONE     0
#define LRO_TYPE_IPV4_TCP 1
#define LRO_TYPE_IPV6_TCP 2
#define LRO_TYPE_IPV4_UDP 3
#define LRO_TYPE_IPV6_UDP 4
                uint8_t lro_flags;
#define LRO_FLAG_DECRYPTED 1
                uint16_t vlan_id;       /* VLAN identifier */
                uint16_t s_port;        /* source TCP/UDP port */
                uint16_t d_port;        /* destination TCP/UDP port */
                uint32_t vxlan_vni;     /* VXLAN virtual network identifier */
                union {
                        struct in_addr v4;
                        struct in6_addr v6;
                } s_addr;       /* source IPv4/IPv6 address */
                union {
                        struct in_addr v4;
                        struct in6_addr v6;
                } d_addr;       /* destination IPv4/IPv6 address */
        };
};

_Static_assert(sizeof(union lro_address) == sizeof(u_long) * LRO_RAW_ADDRESS_MAX,
    "The raw field in the lro_address union does not cover the whole structure.");

/* Optimize address comparison by comparing one unsigned long at a time: */

static inline bool
lro_address_compare(const union lro_address *pa, const union lro_address *pb)
{
        if (pa->lro_type == LRO_TYPE_NONE && pb->lro_type == LRO_TYPE_NONE) {
                return (true);
        } else for (unsigned i = 0; i < LRO_RAW_ADDRESS_MAX; i++) {
                if (pa->raw[i] != pb->raw[i])
                        return (false);
        }
        return (true);
}

struct lro_parser {
        union lro_address data;
        union {
                uint8_t *l3;
                struct ip *ip4;
                struct ip6_hdr *ip6;
        };
        union {
                uint8_t *l4;
                struct tcphdr *tcp;
                struct udphdr *udp;
        };
        uint16_t total_hdr_len;
};

/* This structure is zeroed frequently, try to keep it small. */
struct lro_entry {
        LIST_ENTRY(lro_entry)   next;
        LIST_ENTRY(lro_entry)   hash_next;
        struct mbuf             *m_head;
        struct mbuf             *m_tail;
        struct mbuf             *m_last_mbuf;
        struct lro_parser       outer;
        struct lro_parser       inner;
        uint32_t                next_seq;       /* tcp_seq */
        uint32_t                ack_seq;        /* tcp_seq */
        uint32_t                tsval;
        uint32_t                tsecr;
        uint16_t                compressed;
        uint16_t                uncompressed;
        uint16_t                window;
        uint16_t                flags : 12,     /* 12 TCP header bits */
                                timestamp : 1,
                                needs_merge : 1,
                                reserved : 2;   /* unused */
        struct bintime          alloc_time;     /* time when entry was allocated */
};

LIST_HEAD(lro_head, lro_entry);

struct lro_mbuf_sort {
        uint64_t seq;
        struct mbuf *mb;
};

/* NB: This is part of driver structs. */
struct lro_ctrl {
        struct ifnet    *ifp;
        struct lro_mbuf_sort *lro_mbuf_data;
        struct bintime  lro_last_queue_time;    /* last time data was queued */
        uint64_t        lro_queued;
        uint64_t        lro_flushed;
        uint64_t        lro_bad_csum;
        unsigned        lro_cnt;
        unsigned        lro_mbuf_count;
        unsigned        lro_mbuf_max;
        unsigned short  lro_ackcnt_lim;         /* max # of aggregated ACKs */
        unsigned short  lro_cpu;                /* Guess at the cpu we have affinity too */
        unsigned        lro_length_lim;         /* max len of aggregated data */
        u_long          lro_hashsz;
        uint32_t        lro_last_cpu;
        uint32_t        lro_cnt_of_same_cpu;
        struct lro_head *lro_hash;
        struct lro_head lro_active;
        struct lro_head lro_free;
        uint8_t         lro_cpu_is_set;         /* Flag to say its ok to set the CPU on the inp */
};

struct tcp_ackent {
        uint64_t timestamp;     /* hardware or sofware timestamp, valid if TSTMP_LRO or TSTMP_HDRW set */
        uint32_t seq;           /* th_seq value */
        uint32_t ack;           /* th_ack value */
        uint32_t ts_value;      /* If ts option value, valid if HAS_TSTMP is set */
        uint32_t ts_echo;       /* If ts option echo, valid if HAS_TSTMP is set */
        uint16_t win;           /* TCP window */
        uint16_t flags;         /* Flags to say if TS is present and type of timestamp and th_flags */
        uint8_t  codepoint;     /* IP level codepoint including ECN bits */
        uint8_t  ack_val_set;   /* Classification of ack used by the stack */
        uint8_t  pad[2];        /* To 32 byte boundary */
};

/* We use two M_PROTO on the mbuf */
#define M_ACKCMP        M_PROTO4   /* Indicates LRO is sending in a  Ack-compression mbuf */
#define M_LRO_EHDRSTRP  M_PROTO6   /* Indicates that LRO has stripped the etherenet header */

#define TCP_LRO_LENGTH_MAX      (65535 - 255)   /* safe value with room for outer headers */
#define TCP_LRO_ACKCNT_MAX      65535           /* unlimited */

#define TCP_LRO_TS_OPTION       ntohl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |\
    (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)

static inline struct tcphdr *
tcp_lro_get_th(struct mbuf *m)
{
        return ((struct tcphdr *)((char *)m->m_data +
            m->m_pkthdr.lro_tcp_h_off));
}

extern long tcplro_stacks_wanting_mbufq;

int tcp_lro_init(struct lro_ctrl *);
int tcp_lro_init_args(struct lro_ctrl *, struct ifnet *, unsigned, unsigned);
void tcp_lro_free(struct lro_ctrl *);
void tcp_lro_flush_inactive(struct lro_ctrl *, const struct timeval *);
void tcp_lro_flush_all(struct lro_ctrl *);
extern int (*tcp_lro_flush_tcphpts)(struct lro_ctrl *, struct lro_entry *);
int tcp_lro_rx(struct lro_ctrl *, struct mbuf *, uint32_t);
void tcp_lro_queue_mbuf(struct lro_ctrl *, struct mbuf *);
void tcp_lro_reg_mbufq(void);
void tcp_lro_dereg_mbufq(void);

#define TCP_LRO_NO_ENTRIES      -2
#define TCP_LRO_CANNOT          -1
#define TCP_LRO_NOT_SUPPORTED   1

#endif /* _TCP_LRO_H_ */