RTAX_AUTHOR
#define INFO_AUTHOR(I) ((I)->rti_info[RTAX_AUTHOR])
case RTAX_AUTHOR:
rtinfo.rti_info[RTAX_AUTHOR] = src;
#define rti_author rti_info[RTAX_AUTHOR]
rtinfo.rti_info[RTAX_AUTHOR] = (struct sockaddr *)&icmpgw;