ATMIOC_CLIP
#define ATMARPD_CTRL _IO('a',ATMIOC_CLIP+1) /* become atmarpd ctrl sock */
#define ATMARP_MKIP _IO('a',ATMIOC_CLIP+2) /* attach socket to IP */
#define ATMARP_SETENTRY _IO('a',ATMIOC_CLIP+3) /* fill or hide ARP entry */
#define ATMARP_ENCAP _IO('a',ATMIOC_CLIP+5) /* change encapsulation */
#define SIOCMKCLIP _IO('a',ATMIOC_CLIP) /* create IP interface */