+#define PPP_HDRLEN 4 /* octets for standard ppp header */
+#define PPP_FCSLEN 2 /* octets for FCS */
+
+#define PPP_ADDRESS(cp) ((cp)[0])
+#define PPP_CONTROL(cp) ((cp)[1])
+#define PPP_PROTOCOL(cp) (((cp)[2] << 8) + (cp)[3])
+
+#define PPP_ALLSTATIONS 0xff /* All-Stations broadcast address */
+#define PPP_UI 0x03 /* Unnumbered Information */
+#define PPP_FLAG 0x7e /* Flag Sequence */
+#define PPP_ESCAPE 0x7d /* Asynchronous Control Escape */
+#define PPP_TRANS 0x20 /* Asynchronous transparency modifier */
+
+/*
+ * Protocol field values.
+ */
+#define PPP_IP 0x21 /* Internet Protocol */
+#define PPP_XNS 0x25 /* Xerox NS */
+#define PPP_VJC_COMP 0x2d /* VJ compressed TCP */
+#define PPP_VJC_UNCOMP 0x2f /* VJ uncompressed TCP */
+#define PPP_COMP 0xfd /* compressed packet */
+#define PPP_LCP 0xc021 /* Link Control Protocol */
+#define PPP_CCP 0x80fd /* Compression Control Protocol */
+
+/*
+ * Important FCS values.
+ */
+#define PPP_INITFCS 0xffff /* Initial FCS value */
+#define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
+#define PPP_FCS(fcs, c) (((fcs) >> 8) ^ fcstab[((fcs) ^ (c)) & 0xff])
+
+/*
+ * Packet sizes
+ */
+#define PPP_MTU 1500 /* Default MTU (size of Info field) */
+#define PPP_MRU 1500 /* Default MRU (max receive unit) */
+#define PPP_MAXMRU 65000 /* Largest MRU we allow */
+#define PPP_HDRLEN 4 /* sizeof(struct ppp_header) must be 4 */
+
+/*
+ * A 32-bit unsigned integral type.
+ */
+#ifdef UINT32_T
+typedef UINT32_T u_int32_t;
+#else
+typedef unsigned long u_int32_t;
+#endif
+
+/* Extended asyncmap - allows any character to be escaped. */
+typedef u_int32_t ext_accm[8];
+
+/*
+ * Statistics.
+ */
+struct pppstat {
+ u_int ppp_ibytes; /* bytes received */
+ u_int ppp_ipackets; /* packets received */
+ u_int ppp_ierrors; /* receive errors */
+ u_int ppp_obytes; /* bytes sent */
+ u_int ppp_opackets; /* packets sent */
+ u_int ppp_oerrors; /* transmit errors */
+};
+
+struct vjstat {
+ u_int sls_packets; /* outbound packets */
+ u_int sls_compressed; /* outbound compressed packets */
+ u_int sls_searches; /* searches for connection state */
+ u_int sls_misses; /* times couldn't find conn. state */
+ u_int sls_uncompressedin; /* inbound uncompressed packets */
+ u_int sls_compressedin; /* inbound compressed packets */
+ u_int sls_errorin; /* inbound unknown type packets */
+ u_int sls_tossed; /* inbound packets tossed because of error */
+};
+
+struct ppp_stats {
+ struct pppstat p;
+ struct vjstat vj;
+};
+
+/*
+ * What to do with network protocol (NP) packets.
+ */
+
+enum NPmode {
+ NPMODE_PASS, /* pass the packet through */
+ NPMODE_DROP, /* silently drop the packet */
+ NPMODE_ERROR, /* return an error */
+ NPMODE_QUEUE /* save it up for later. */
+};
+
+struct npioctl {
+ int protocol; /* PPP procotol, e.g. PPP_IP */
+ enum NPmode mode;
+};
+
+/* Structure describing a CCP configuration option, for SIOCSCOMPRESS */
+#define MAX_PPP_OPTION 32
+struct ppp_option_data {
+ u_int length;
+ int transmit;
+ u_char opt_data[MAX_PPP_OPTION];
+};
+
+/* Bit definitions for SIOC[GS]IFCOMP. */
+#define CCP_ISOPEN 1
+#define CCP_ISUP 2
+#define CCP_COMP_RUN 4
+#define CCP_DECOMP_RUN 8
+#define CCP_ERROR 0x10
+#define CCP_FATALERROR 0x20
+
+/*
+ * Ioctl definitions.
+ */
+