source: freewrt/package/aiccu/extra/common/dn_skipname.c@ 621d5d2

#include <errno.h>
#include <resolv.h>

/* Ripped from glibc 2.4 sources. */

/*
 * ns_name_skip(ptrptr, eom)
 *      Advance *ptrptr to skip over the compressed name it points at.
 * return:
 *      0 on success, -1 (with errno set) on failure.
 */
int ns_name_skip(const u_char **ptrptr, const u_char *eom)
{
        const u_char *cp;
        u_int n;

        cp = *ptrptr;
        while (cp < eom && (n = *cp++) != 0)
        {
                /* Check for indirection. */
                switch (n & NS_CMPRSFLGS) {
                case 0:                 /* normal case, n == len */
                        cp += n;
                        continue;
                case NS_CMPRSFLGS:      /* indirection */
                        cp++;
                        break;
                default:                /* illegal type */
                        errno = EMSGSIZE;
                        return (-1);
                }
                break;
        }
        if (cp > eom)
        {
                errno = EMSGSIZE;
                return (-1);
        }
        *ptrptr = cp;
        return (0);
}

int dn_skipname(const u_char *ptr, const u_char *eom)
{
        const u_char *saveptr = ptr;

        if(ns_name_skip(&ptr, eom) == -1)
                return (-1);
        return (ptr - saveptr);
}