IPOPT_LSRR
if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
case IPOPT_LSRR:
case IPOPT_LSRR:
case IPOPT_LSRR:
((u_char *)(ip + 1))[1] != IPOPT_LSRR) {
case IPOPT_LSRR:
case IPOPT_LSRR:
*p++ = IPOPT_LSRR;