IP_CMSG_RETOPTS 502 net/ipv4/ip_sockglue.c inet->cmsg_flags |= IP_CMSG_RETOPTS; IP_CMSG_RETOPTS 504 net/ipv4/ip_sockglue.c inet->cmsg_flags &= ~IP_CMSG_RETOPTS; IP_CMSG_RETOPTS 1020 net/ipv4/ip_sockglue.c val = (inet->cmsg_flags & IP_CMSG_RETOPTS) != 0;