【Atheros】pktgen的ipv6地址处理函数参考及ipv6基本知识

/*
 * scan_ip6, fmt_ip taken from dietlibc-0.21
 * Author Felix von Leitner <felix-dietlibc@fefe.de>
 *
 * Slightly modified for kernel.
 * Should be candidate for net/ipv4/utils.c
 * --ro
 */

static unsigned int scan_ip6(const char *s, char ip[16])
{
    unsigned int i;
    unsigned int len = 0;
    unsigned long u;
    char suffix[16];
    unsigned int prefixlen = 0;
    unsigned int suffixlen = 0;
    __be32 tmp;
    char *pos;

    for (i = 0; i < 16; i++)
        ip[i] = 0;

    for (;;) {
        if (*s == ‘:‘) {
            len++;
            if (s[1] == ‘:‘) {    /* Found "::", skip to part 2 */
                s += 2;
                len++;
                break;
            }
            s++;
        }

        u = simple_strtoul(s, &pos, 16);
        i = pos - s;
        if (!i)
            return 0;
        if (prefixlen == 12 && s[i] == ‘.‘) {

            /* the last 4 bytes may be written as IPv4 address */

            tmp = in_aton(s);
            memcpy((struct in_addr *)(ip + 12), &tmp, sizeof(tmp));
            return i + len;
        }
        ip[prefixlen++] = (u >> 8);
        ip[prefixlen++] = (u & 255);
        s += i;
        len += i;
        if (prefixlen == 16)
            return len;
    }

/* part 2, after "::" */
    for (;;) {
        if (*s == ‘:‘) {
            if (suffixlen == 0)
                break;
            s++;
            len++;
        } else if (suffixlen != 0)
            break;

        u = simple_strtol(s, &pos, 16);
        i = pos - s;
        if (!i) {
            if (*s)
                len--;
            break;
        }
        if (suffixlen + prefixlen <= 12 && s[i] == ‘.‘) {
            tmp = in_aton(s);
            memcpy((struct in_addr *)(suffix + suffixlen), &tmp,
                   sizeof(tmp));
            suffixlen += 4;
            len += strlen(s);
            break;
        }
        suffix[suffixlen++] = (u >> 8);
        suffix[suffixlen++] = (u & 255);
        s += i;
        len += i;
        if (prefixlen + suffixlen == 16)
            break;
    }
    for (i = 0; i < suffixlen; i++)
        ip[16 - suffixlen + i] = suffix[i];
    return len;
}

static unsigned int fmt_ip6(char *s, const char ip[16])
{
    unsigned int len;
    unsigned int i;
    unsigned int temp;
    unsigned int compressing;
    int j;

    len = 0;
    compressing = 0;
    for (j = 0; j < 16; j += 2) {

#ifdef V4MAPPEDPREFIX
        if (j == 12 && !memcmp(ip, V4mappedprefix, 12)) {
            inet_ntoa_r(*(struct in_addr *)(ip + 12), s);
            temp = strlen(s);
            return len + temp;
        }
#endif
        temp = ((unsigned long)(unsigned char)ip[j] << 8) +
            (unsigned long)(unsigned char)ip[j + 1];
        if (temp == 0) {
            if (!compressing) {
                compressing = 1;
                if (j == 0) {
                    *s++ = ‘:‘;
                    ++len;
                }
            }
        } else {
            if (compressing) {
                compressing = 0;
                *s++ = ‘:‘;
                ++len;
            }
            i = fmt_xlong(s, temp);
            len += i;
            s += i;
            if (j < 14) {
                *s++ = ‘:‘;
                ++len;
            }
        }
    }
    if (compressing) {
        *s++ = ‘:‘;
        ++len;
    }
    *s = 0;
    return len;
}