+#define IFQ_MAXLEN 50
+#define IFNET_SLOWHZ 1 /* granularity is 1 second */
+
+/*
+ * Interface request structure used for socket
+ * ioctl's. All interface ioctl's must have parameter
+ * definitions which begin with ifr_name. The
+ * remainder may be interface specific.
+ */
+struct ifreq {
+#define IFNAMSIZ 16
+ char ifr_name[IFNAMSIZ]; /* if name, e.g. "en0" */
+ union {
+ struct sockaddr ifru_addr;
+ struct sockaddr ifru_dstaddr;
+ short ifru_flags;
+ caddr_t ifru_data;
+ } ifr_ifru;
+#define ifr_addr ifr_ifru.ifru_addr /* address */
+#define ifr_dstaddr ifr_ifru.ifru_dstaddr /* other end of p-to-p link */
+#define ifr_flags ifr_ifru.ifru_flags /* flags */
+#define ifr_data ifr_ifru.ifru_data /* for use by interface */
+};
+
+/*
+ * Structure used in SIOCGIFCONF request.
+ * Used to retrieve interface configuration
+ * for machine (useful for programs which
+ * must know all networks accessible).
+ */
+struct ifconf {
+ int ifc_len; /* size of associated buffer */
+ union {
+ caddr_t ifcu_buf;
+ struct ifreq *ifcu_req;
+ } ifc_ifcu;
+#define ifc_buf ifc_ifcu.ifcu_buf /* buffer address */
+#define ifc_req ifc_ifcu.ifcu_req /* array of structures returned */
+};
+
+/*
+ * 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 1 /* entry in use */
+#define ATF_COM 2 /* completed entry (enaddr valid) */
+#define ATF_PERM 4 /* permanent entry */
+#define ATF_PUBL 8 /* publish entry (respond for other host) */
+