+#define PHASE_INITIALIZE 1
+#define PHASE_SERIALCONN 2
+#define PHASE_DORMANT 3
+#define PHASE_ESTABLISH 4
+#define PHASE_AUTHENTICATE 5
+#define PHASE_CALLBACK 6
+#define PHASE_NETWORK 7
+#define PHASE_RUNNING 8
+#define PHASE_TERMINATE 9
+#define PHASE_DISCONNECT 10
+#define PHASE_HOLDOFF 11
+
+/*
+ * The following struct gives the addresses of procedures to call
+ * for a particular protocol.
+ */
+struct protent {
+ u_short protocol; /* PPP protocol number */
+ /* Initialization procedure */
+ void (*init) __P((int unit));
+ /* Process a received packet */
+ void (*input) __P((int unit, u_char *pkt, int len));
+ /* Process a received protocol-reject */
+ void (*protrej) __P((int unit));
+ /* Lower layer has come up */
+ void (*lowerup) __P((int unit));
+ /* Lower layer has gone down */
+ void (*lowerdown) __P((int unit));
+ /* Open the protocol */
+ void (*open) __P((int unit));
+ /* Close the protocol */
+ void (*close) __P((int unit, char *reason));
+ /* Print a packet in readable form */
+ int (*printpkt) __P((u_char *pkt, int len,
+ void (*printer) __P((void *, char *, ...)),
+ void *arg));
+ /* Process a received data packet */
+ void (*datainput) __P((int unit, u_char *pkt, int len));
+ bool enabled_flag; /* 0 iff protocol is disabled */
+ char *name; /* Text name of protocol */
+ char *data_name; /* Text name of corresponding data protocol */
+ option_t *options; /* List of command-line options */
+ /* Check requested options, assign defaults */
+ void (*check_options) __P((void));
+ /* Configure interface for demand-dial */
+ int (*demand_conf) __P((int unit));
+ /* Say whether to bring up link for this pkt */
+ int (*active_pkt) __P((u_char *pkt, int len));
+};
+
+/* Table of pointers to supported protocols */
+extern struct protent *protocols[];
+
+/*
+ * This struct contains pointers to a set of procedures for
+ * doing operations on a "channel". A channel provides a way
+ * to send and receive PPP packets - the canonical example is
+ * a serial port device in PPP line discipline (or equivalently
+ * with PPP STREAMS modules pushed onto it).
+ */
+struct channel {
+ /* set of options for this channel */
+ option_t *options;
+ /* find and process a per-channel options file */
+ void (*process_extra_options) __P((void));
+ /* check all the options that have been given */
+ void (*check_options) __P((void));
+ /* get the channel ready to do PPP, return a file descriptor */
+ int (*connect) __P((void));
+ /* we're finished with the channel */
+ void (*disconnect) __P((void));
+ /* put the channel into PPP `mode' */
+ int (*establish_ppp) __P((int));
+ /* take the channel out of PPP `mode', restore loopback if demand */
+ void (*disestablish_ppp) __P((int));
+ /* set the transmit-side PPP parameters of the channel */
+ void (*send_config) __P((int, u_int32_t, int, int));
+ /* set the receive-side PPP parameters of the channel */
+ void (*recv_config) __P((int, u_int32_t, int, int));
+ /* cleanup on error or normal exit */
+ void (*cleanup) __P((void));
+ /* close the device, called in children after fork */
+ void (*close) __P((void));
+};
+
+extern struct channel *the_channel;
+
+#define ppp_send_config(unit, mtu, accm, pc, acc) \
+do { \
+ if (the_channel->send_config) \
+ (*the_channel->send_config)((mtu), (accm), (pc), (acc)); \
+} while (0)
+
+#define ppp_recv_config(unit, mtu, accm, pc, acc) \
+do { \
+ if (the_channel->send_config) \
+ (*the_channel->recv_config)((mtu), (accm), (pc), (acc)); \
+} while (0)