+
+/*
+ * Definitions of bits in internet address integers.
+ * On subnets, the decomposition of addresses to host and net parts
+ * is done according to subnet mask, not the masks here.
+ */
+#define IN_CLASSA(i) (((long)(i) & 0x80000000) == 0)
+#define IN_CLASSA_NET 0xff000000
+#define IN_CLASSA_NSHIFT 24
+#define IN_CLASSA_HOST 0x00ffffff
+#define IN_CLASSA_MAX 128
+
+#define IN_CLASSB(i) (((long)(i) & 0xc0000000) == 0x80000000)
+#define IN_CLASSB_NET 0xffff0000
+#define IN_CLASSB_NSHIFT 16
+#define IN_CLASSB_HOST 0x0000ffff
+#define IN_CLASSB_MAX 65536
+
+#define IN_CLASSC(i) (((long)(i) & 0xe0000000) == 0xc0000000)
+#define IN_CLASSC_NET 0xffffff00
+#define IN_CLASSC_NSHIFT 8
+#define IN_CLASSC_HOST 0x000000ff
+
+#define IN_CLASSD(i) (((long)(i) & 0xf0000000) == 0xe0000000)
+#define IN_MULTICAST(i) IN_CLASSD(i)
+
+#define IN_EXPERIMENTAL(i) (((long)(i) & 0xe0000000) == 0xe0000000)
+#define IN_BADCLASS(i) (((long)(i) & 0xf0000000) == 0xf0000000)
+
+#define INADDR_ANY (u_long)0x00000000
+#define INADDR_BROADCAST (u_long)0xffffffff /* must be masked */
+#ifndef KERNEL
+#define INADDR_NONE 0xffffffff /* -1 return */
+#endif
+
+#define IN_LOOPBACKNET 127 /* official! */
+
+/*
+ * Socket address, internet style.
+ */
+struct sockaddr_in {
+ short sin_family;
+ u_short sin_port;
+ struct in_addr sin_addr;
+ char sin_zero[8];
+};
+
+/*
+ * Options for use with [gs]etsockopt at the IP level.
+ */
+#define IP_OPTIONS 1 /* set/get IP per-packet options */
+
+#ifdef KERNEL
+extern struct domain inetdomain;
+extern struct protosw inetsw[];
+struct in_addr in_makeaddr();
+u_long in_netof(), in_lnaof();
+#endif