/* Copyright (c) 2008 Victor Julien <victor@inliniac.net> */

#include "eidps-common.h"
#include "decode.h"
#include "decode-icmpv6.h"
#include "util-unittest.h"

/**
 * \brief Calculates the checksum for the ICMPV6 packet
 *
 * \param shdr Pointer to source address field from the IPV6 packet.  Used as a
 *             part of the psuedoheader for computing the checksum
 * \param pkt  Pointer to the start of the ICMPV6 packet
 * \param tlen Total length of the ICMPV6 packet(header + payload)
 *
 * \retval csum Checksum for the ICMPV6 packet
 */
static inline uint16_t ICMPV6CalculateChecksum(uint16_t *shdr, uint16_t *pkt,
                                               uint16_t tlen)
{
    uint16_t pad = 0;
    uint32_t csum = shdr[0];

    csum += shdr[1] + shdr[2] + shdr[3] + shdr[4] + shdr[5] + shdr[6] +
        shdr[7] + shdr[8] + shdr[9] + shdr[10] + shdr[11] + shdr[12] +
        shdr[13] + shdr[14] + shdr[15] + htons(58 + tlen);

    csum += pkt[0];

    tlen -= 4;
    pkt += 2;

    while (tlen >= 64) {
        csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
            pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
            pkt[14] + pkt[15] + pkt[16] + pkt[17] + pkt[18] + pkt[19] +
            pkt[20] + pkt[21] + pkt[22] + pkt[23] + pkt[24] + pkt[25] +
            pkt[26] + pkt[27] + pkt[28] + pkt[29] + pkt[30] + pkt[31];
        tlen -= 64;
        pkt += 32;
    }

    while (tlen >= 32) {
        csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
            pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
            pkt[14] + pkt[15];
        tlen -= 32;
        pkt += 16;
    }

    while(tlen >= 8) {
        csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
        tlen -= 8;
        pkt += 4;
    }

    while(tlen >= 4) {
        csum += pkt[0] + pkt[1];
        tlen -= 4;
        pkt += 2;
    }

    while (tlen > 1) {
        csum += pkt[0];
        tlen -= 2;
        pkt += 1;
    }

    if (tlen == 1) {
        *(uint8_t *)(&pad) = (*(uint8_t *)pkt);
        csum += pad;
    }

    csum = (csum >> 16) + (csum & 0x0000FFFF);

    return (uint16_t) ~csum;
}

void DecodeICMPV6(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt, uint16_t len, PacketQueue *pq)
{
    PerfCounterIncr(dtv->counter_icmpv6, tv->pca);

    if (len < ICMPV6_HEADER_LEN) {
        /** \todo decode event */
        return;
    }

    p->icmpv6h = (ICMPV6Hdr *)pkt;

#ifdef DEBUG
    printf("ICMPV6 TYPE %" PRIu32 " CODE %" PRIu32 "\n", p->icmpv6h->type, p->icmpv6h->code);
#endif

    p->proto = IPPROTO_ICMPV6;
    return;
}

static int ICMPV6CalculateValidChecksumtest01(void) {
    uint16_t csum = 0;

    uint8_t raw_ipv6[] = {
        0x00, 0x00, 0x86, 0x05, 0x80, 0xda, 0x00, 0x60,
        0x97, 0x07, 0x69, 0xea, 0x86, 0xdd, 0x60, 0x00,
        0x00, 0x00, 0x00, 0x44, 0x3a, 0x40, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x60,
        0x97, 0xff, 0xfe, 0x07, 0x69, 0xea, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x00,
        0x86, 0xff, 0xfe, 0x05, 0x80, 0xda, 0x03, 0x00,
        0xf7, 0x52, 0x00, 0x00, 0x00, 0x00, 0x60, 0x00,
        0x00, 0x00, 0x00, 0x14, 0x11, 0x01, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x00,
        0x86, 0xff, 0xfe, 0x05, 0x80, 0xda, 0x3f, 0xfe,
        0x05, 0x01, 0x04, 0x10, 0x00, 0x00, 0x02, 0xc0,
        0xdf, 0xff, 0xfe, 0x47, 0x03, 0x3e, 0xa0, 0x75,
        0x82, 0x9b, 0x00, 0x14, 0x82, 0x8b, 0x01, 0x01,
        0x00, 0x00, 0xf9, 0xc8, 0xe7, 0x36, 0xf5, 0xed,
        0x08, 0x00};

    csum = *( ((uint16_t *)(raw_ipv6 + 56)));

    return (csum == ICMPV6CalculateChecksum((uint16_t *)(raw_ipv6 + 14 + 8),
                                            (uint16_t *)(raw_ipv6 + 54), 68));
}

static int ICMPV6CalculateInvalidChecksumtest02(void) {
    uint16_t csum = 0;

    uint8_t raw_ipv6[] = {
        0x00, 0x00, 0x86, 0x05, 0x80, 0xda, 0x00, 0x60,
        0x97, 0x07, 0x69, 0xea, 0x86, 0xdd, 0x60, 0x00,
        0x00, 0x00, 0x00, 0x44, 0x3a, 0x40, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x60,
        0x97, 0xff, 0xfe, 0x07, 0x69, 0xea, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x00,
        0x86, 0xff, 0xfe, 0x05, 0x80, 0xda, 0x03, 0x00,
        0xf7, 0x52, 0x00, 0x00, 0x00, 0x00, 0x60, 0x00,
        0x00, 0x00, 0x00, 0x14, 0x11, 0x01, 0x3f, 0xfe,
        0x05, 0x07, 0x00, 0x00, 0x00, 0x01, 0x02, 0x00,
        0x86, 0xff, 0xfe, 0x05, 0x80, 0xda, 0x3f, 0xfe,
        0x05, 0x01, 0x04, 0x10, 0x00, 0x00, 0x02, 0xc0,
        0xdf, 0xff, 0xfe, 0x47, 0x03, 0x3e, 0xa0, 0x75,
        0x82, 0x9b, 0x00, 0x14, 0x82, 0x8b, 0x01, 0x01,
        0x00, 0x00, 0xf9, 0xc8, 0xe7, 0x36, 0xf5, 0xed,
        0x08, 0x01};

    csum = *( ((uint16_t *)(raw_ipv6 + 56)));

    return (csum == ICMPV6CalculateChecksum((uint16_t *)(raw_ipv6 + 14 + 8),
                                            (uint16_t *)(raw_ipv6 + 54), 68));
}

/**
 * \brief Registers ICMPV6 unit tests
 * \todo More ICMPv6 tests
 */
void DecodeICMPV6RegisterTests(void)
{
    UtRegisterTest("ICMPV6CalculateValidChecksumtest01",
                   ICMPV6CalculateValidChecksumtest01, 1);
    UtRegisterTest("ICMPV6CalculateInValidChecksumtest02",
                   ICMPV6CalculateInvalidChecksumtest02, 0);
}