unused since "rewrite to merge arp and routing tables"
in CSRG if_ether.c 7.14 (Berkeley) 06/25/91

not used in pppd as the #if RTM_VERSION >= 3, path is taken

Index: sys/net/if_arp.h
===================================================================
RCS file: /cvs/src/sys/net/if_arp.h,v
diff -u -p -r1.7 if_arp.h
--- sys/net/if_arp.h	24 Jan 2017 10:08:30 -0000	1.7
+++ sys/net/if_arp.h	11 Oct 2024 07:20:19 -0000
@@ -71,19 +71,4 @@ struct	arphdr {
 	u_int8_t  ar_tpa[];	/* target protocol address */
 #endif
 };
-
-/*
- * ARP ioctl request
- */
-struct arpreq {
-	struct	sockaddr arp_pa;		/* protocol address */
-	struct	sockaddr arp_ha;		/* hardware address */
-	int	arp_flags;			/* flags */
-};
-/*  arp_flags and at_flags field values */
-#define	ATF_INUSE	0x01	/* entry in use */
-#define ATF_COM		0x02	/* completed entry (enaddr valid) */
-#define	ATF_PERM	0x04	/* permanent entry */
-#define	ATF_PUBL	0x08	/* publish entry (respond for other host) */
-#define	ATF_USETRAILERS	0x10	/* has requested trailers */
 #endif /* _NET_IF_ARP_H_ */