+#define IFQ_MAXLEN 50
+#define IFNET_SLOWHZ 1 /* granularity is 1 second */
+
+/*
+ * The ifaddr structure contains information about one address
+ * of an interface. They are maintained by the different address families,
+ * are allocated and attached when an address is set, and are linked
+ * together so all addresses for an interface can be located.
+ */
+struct ifaddr {
+ struct sockaddr *ifa_addr; /* address of interface */
+ struct sockaddr *ifa_dstaddr; /* other end of p-to-p link */
+#define ifa_broadaddr ifa_dstaddr /* broadcast address interface */
+ struct sockaddr *ifa_netmask; /* used to determine subnet */
+ struct ifnet *ifa_ifp; /* back-pointer to interface */
+ struct ifaddr *ifa_next; /* next address for interface */
+ void (*ifa_rtrequest)(); /* check or clean routes (+ or -)'d */
+ u_short ifa_flags; /* mostly rt_flags for cloning */
+ short ifa_refcnt; /* extra to malloc for link info */
+ int ifa_metric; /* cost of going out this interface */
+#ifdef notdef
+ struct rtentry *ifa_rt; /* XXXX for ROUTETOIF ????? */
+#endif
+};
+#define IFA_ROUTE RTF_UP /* route installed */
+
+/*
+ * Message format for use in obtaining information about interfaces
+ * from getkerninfo and the routing socket
+ */
+struct if_msghdr {
+ u_short ifm_msglen; /* to skip over non-understood messages */
+ u_char ifm_version; /* future binary compatability */
+ u_char ifm_type; /* message type */
+ int ifm_addrs; /* like rtm_addrs */
+ int ifm_flags; /* value of if_flags */
+ u_short ifm_index; /* index for associated ifp */
+ struct if_data ifm_data;/* statistics and other data about if */
+};
+
+/*
+ * Message format for use in obtaining information about interface addresses
+ * from getkerninfo and the routing socket
+ */
+struct ifa_msghdr {
+ u_short ifam_msglen; /* to skip over non-understood messages */
+ u_char ifam_version; /* future binary compatability */
+ u_char ifam_type; /* message type */
+ int ifam_addrs; /* like rtm_addrs */
+ int ifam_flags; /* value of ifa_flags */
+ u_short ifam_index; /* index for associated ifp */
+ int ifam_metric; /* value of ifa_metric */
+};
+
+/*
+ * 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;
+ struct sockaddr ifru_broadaddr;
+ short ifru_flags;
+ int ifru_metric;
+ 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_broadaddr ifr_ifru.ifru_broadaddr /* broadcast address */
+#define ifr_flags ifr_ifru.ifru_flags /* flags */
+#define ifr_metric ifr_ifru.ifru_metric /* metric */
+#define ifr_data ifr_ifru.ifru_data /* for use by interface */
+};
+
+struct ifaliasreq {
+ char ifra_name[IFNAMSIZ]; /* if name, e.g. "en0" */
+ struct sockaddr ifra_addr;
+ struct sockaddr ifra_broadaddr;
+ struct sockaddr ifra_mask;
+};
+
+/*
+ * 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 */
+};
+
+#include <net/if_arp.h>
+