rte_ip4.h

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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 1982, 1986, 1990, 1993
 *      The Regents of the University of California.
 * Copyright(c) 2010-2014 Intel Corporation.
 * Copyright(c) 2014 6WIND S.A.
 * All rights reserved.
 */

#ifndef _RTE_IP4_H_
#define _RTE_IP4_H_

#include <stdint.h>

#ifdef RTE_EXEC_ENV_WINDOWS
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#endif

#include <rte_byteorder.h>
#include <rte_cksum.h>
#include <rte_mbuf.h>

#ifdef __cplusplus
extern "C" {
#endif

struct __rte_aligned(2) rte_ipv4_hdr {
    __extension__
    union {
        uint8_t version_ihl;    
        struct {
#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
            uint8_t ihl:4;     
            uint8_t version:4; 
#elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN
            uint8_t version:4; 
            uint8_t ihl:4;     
#endif
        };
    };
    uint8_t  type_of_service;   
    rte_be16_t total_length;    
    rte_be16_t packet_id;       
    rte_be16_t fragment_offset; 
    uint8_t  time_to_live;      
    uint8_t  next_proto_id;     
    rte_be16_t hdr_checksum;    
    rte_be32_t src_addr;        
    rte_be32_t dst_addr;        
} __rte_packed;

#define RTE_IPV4(a, b, c, d) ((uint32_t)(((a) & 0xff) << 24) | \
                       (((b) & 0xff) << 16) | \
                       (((c) & 0xff) << 8)  | \
                       ((d) & 0xff))

#define RTE_IPV4_MAX_PKT_LEN        65535

#define RTE_IPV4_HDR_IHL_MASK   (0x0f)

#define RTE_IPV4_IHL_MULTIPLIER (4)

/* Type of Service fields */
#define RTE_IPV4_HDR_DSCP_MASK  (0xfc)
#define RTE_IPV4_HDR_ECN_MASK   (0x03)
#define RTE_IPV4_HDR_ECN_CE RTE_IPV4_HDR_ECN_MASK

/* Fragment Offset * Flags. */
#define RTE_IPV4_HDR_DF_SHIFT   14
#define RTE_IPV4_HDR_MF_SHIFT   13
#define RTE_IPV4_HDR_FO_SHIFT   3

#define RTE_IPV4_HDR_DF_FLAG    (1 << RTE_IPV4_HDR_DF_SHIFT)
#define RTE_IPV4_HDR_MF_FLAG    (1 << RTE_IPV4_HDR_MF_SHIFT)

#define RTE_IPV4_HDR_OFFSET_MASK    ((1 << RTE_IPV4_HDR_MF_SHIFT) - 1)

#define RTE_IPV4_HDR_OFFSET_UNITS   8

/* IPv4 options */
#define RTE_IPV4_HDR_OPT_EOL       0
#define RTE_IPV4_HDR_OPT_NOP       1
#define RTE_IPV4_HDR_OPT_COPIED(v) ((v) & 0x80)
#define RTE_IPV4_HDR_OPT_MAX_LEN   40

/*
 * IPv4 address types
 */
#define RTE_IPV4_ANY              ((uint32_t)0x00000000) 
#define RTE_IPV4_LOOPBACK         ((uint32_t)0x7f000001) 
#define RTE_IPV4_BROADCAST        ((uint32_t)0xe0000000) 
#define RTE_IPV4_ALLHOSTS_GROUP   ((uint32_t)0xe0000001) 
#define RTE_IPV4_ALLRTRS_GROUP    ((uint32_t)0xe0000002) 
#define RTE_IPV4_MAX_LOCAL_GROUP  ((uint32_t)0xe00000ff) 
/*
 * IPv4 Multicast-related macros
 */
#define RTE_IPV4_MIN_MCAST \
    RTE_IPV4(224, 0, 0, 0)          
#define RTE_IPV4_MAX_MCAST \
    RTE_IPV4(239, 255, 255, 255)    
#define RTE_IS_IPV4_MCAST(x) \
    ((x) >= RTE_IPV4_MIN_MCAST && (x) <= RTE_IPV4_MAX_MCAST)

/* IPv4 default fields values */
#define RTE_IPV4_MIN_IHL    (0x5)
#define RTE_IPV4_VHL_DEF    ((IPVERSION << 4) | RTE_IPV4_MIN_IHL)

static inline uint8_t
rte_ipv4_hdr_len(const struct rte_ipv4_hdr *ipv4_hdr)
{
    return (uint8_t)((ipv4_hdr->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
        RTE_IPV4_IHL_MULTIPLIER);
}

static inline uint16_t
rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr)
{
    uint16_t cksum;
    cksum = rte_raw_cksum(ipv4_hdr, rte_ipv4_hdr_len(ipv4_hdr));
    return (uint16_t)~cksum;
}

__rte_experimental
static inline uint16_t
rte_ipv4_cksum_simple(const struct rte_ipv4_hdr *ipv4_hdr)
{
    const uint16_t *v16_h;
    uint32_t ip_cksum;

    /*
     * Compute the sum of successive 16-bit words of the IPv4 header,
     * skipping the checksum field of the header.
     */
    v16_h = (const uint16_t *)ipv4_hdr;
    ip_cksum = v16_h[0] + v16_h[1] + v16_h[2] + v16_h[3] +
        v16_h[4] + v16_h[6] + v16_h[7] + v16_h[8] + v16_h[9];

    /* reduce 32 bit checksum to 16 bits and complement it */
    ip_cksum = (ip_cksum & 0xffff) + (ip_cksum >> 16);
    ip_cksum = (ip_cksum & 0xffff) + (ip_cksum >> 16);
    return (uint16_t)(~ip_cksum);
}

static inline uint16_t
rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
{
    struct ipv4_psd_header {
        uint32_t src_addr; /* IP address of source host. */
        uint32_t dst_addr; /* IP address of destination host. */
        uint8_t  zero;     /* zero. */
        uint8_t  proto;    /* L4 protocol type. */
        uint16_t len;      /* L4 length. */
    } psd_hdr;

    uint32_t l3_len;

    psd_hdr.src_addr = ipv4_hdr->src_addr;
    psd_hdr.dst_addr = ipv4_hdr->dst_addr;
    psd_hdr.zero = 0;
    psd_hdr.proto = ipv4_hdr->next_proto_id;
    if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG)) {
        psd_hdr.len = 0;
    } else {
        l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
        psd_hdr.len = rte_cpu_to_be_16((uint16_t)(l3_len -
            rte_ipv4_hdr_len(ipv4_hdr)));
    }
    return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
}

static inline uint16_t
__rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
{
    uint32_t cksum;
    uint32_t l3_len, l4_len;
    uint8_t ip_hdr_len;

    ip_hdr_len = rte_ipv4_hdr_len(ipv4_hdr);
    l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
    if (l3_len < ip_hdr_len)
        return 0;

    l4_len = l3_len - ip_hdr_len;

    cksum = rte_raw_cksum(l4_hdr, l4_len);
    cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);

    cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);

    return (uint16_t)cksum;
}

static inline uint16_t
rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
{
    uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr);

    cksum = ~cksum;

    /*
     * Per RFC 768: If the computed checksum is zero for UDP,
     * it is transmitted as all ones
     * (the equivalent in one's complement arithmetic).
     */
    if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
        cksum = 0xffff;

    return cksum;
}

static inline uint16_t
__rte_ipv4_udptcp_cksum_mbuf(const struct rte_mbuf *m,
                 const struct rte_ipv4_hdr *ipv4_hdr,
                 uint16_t l4_off)
{
    uint16_t raw_cksum;
    uint32_t cksum;
    uint16_t len;

    if (unlikely(l4_off > m->pkt_len))
        return 0; /* invalid params, return a dummy value */

    len = rte_be_to_cpu_16(ipv4_hdr->total_length) - (uint16_t)rte_ipv4_hdr_len(ipv4_hdr);

    if (rte_raw_cksum_mbuf(m, l4_off, len, &raw_cksum))
        return 0;

    cksum = raw_cksum + rte_ipv4_phdr_cksum(ipv4_hdr, 0);

    cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);

    return (uint16_t)cksum;
}

static inline uint16_t
rte_ipv4_udptcp_cksum_mbuf(const struct rte_mbuf *m,
               const struct rte_ipv4_hdr *ipv4_hdr, uint16_t l4_off)
{
    uint16_t cksum = __rte_ipv4_udptcp_cksum_mbuf(m, ipv4_hdr, l4_off);

    cksum = ~cksum;

    /*
     * Per RFC 768: If the computed checksum is zero for UDP,
     * it is transmitted as all ones
     * (the equivalent in one's complement arithmetic).
     */
    if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
        cksum = 0xffff;

    return cksum;
}

static inline int
rte_ipv4_udptcp_cksum_verify(const struct rte_ipv4_hdr *ipv4_hdr,
                 const void *l4_hdr)
{
    uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr);

    if (cksum != 0xffff)
        return -1;

    return 0;
}

static inline int
rte_ipv4_udptcp_cksum_mbuf_verify(const struct rte_mbuf *m,
                  const struct rte_ipv4_hdr *ipv4_hdr,
                  uint16_t l4_off)
{
    uint16_t cksum = __rte_ipv4_udptcp_cksum_mbuf(m, ipv4_hdr, l4_off);

    if (cksum != 0xffff)
        return -1;

    return 0;
}

#ifdef __cplusplus
}
#endif

#endif /* _RTE_IP_H_ */