#define dhcpv6_for_each_option(start, end, otype, olen, odata)\
for (uint8_t *_o = (uint8_t*)(start); _o + 4 <= (uint8_t*)(end) &&\
#define dhcpv6_for_each_option(start, end, otype, olen, odata)\
for (uint8_t *_o = (uint8_t*)(start); _o + 4 <= (uint8_t*)(end) &&\