MAX_IPOPTLEN
int8_t ipopt_list[MAX_IPOPTLEN]; /* options proper */
#define MAXIPLEN (sizeof(struct ip) + MAX_IPOPTLEN)
#define MAXICMPLEN (ICMP_ADVLENMIN + MAX_IPOPTLEN)
static char old_rr[MAX_IPOPTLEN];
char rspace[MAX_IPOPTLEN]; /* record route space */
icmp_len += MAX_IPOPTLEN;
#define NGATEWAYS ((int)((MAX_IPOPTLEN - IPOPT_MINOFF - 1) / sizeof(u_int32_t)))