PPP程序基本的流程.docVIP

PPP程序基本流程图 PPPD程序用到的几个重要的结构体： typedef struct fsm { int unit; /* Interface unit number */ int protocol; /* Data Link Layer Protocol field value */ int state; /* State */ int flags; /* Contains option bits */ u_char id; /* Current id */ u_char reqid; /* Current request id */ u_char seen_ack; /* Have received valid Ack/Nak/Rej to Req */ int timeouttime; /* Timeout time in milliseconds */ int maxconfreqtransmits; /* Maximum Configure-Request transmissions */ int retransmits; /* Number of retransmissions left */ int maxtermtransmits; /* Maximum Terminate-Request transmissions */ int nakloops; /* Number of nak loops since last ack */ int rnakloops; /* Number of naks received */ int maxnakloops; /* Maximum number of nak loops tolerated */ struct fsm_callbacks *callbacks; /* Callback routines */ char *term_reason; /* Reason for closing protocol */ int term_reason_len; /* Length of term_reason */ } fsm; typedef struct fsm_callbacks { void (*resetci) /* Reset our Configuration Information */ __P((fsm *)); int (*cilen) /* Length of our Configuration Information */ __P((fsm *)); void (*addci) /* Add our Configuration Information */ __P((fsm *, u_char *, int *)); int (*ackci) /* ACK our Configuration Information */ __P((fsm *, u_char *, int)); int (*nakci) /* NAK our Configuration Information */ __P((fsm *, u_char *, int, int)); int (*rejci) /* Reject our Configuration Information */ __P((fsm *, u_char *, int)); int (*reqci) /* Request peers Configuration Information */ __P((fsm *, u_char *, int *, int)); void (*up) /* Called when fsm reaches OPENED state */ __P((fsm *)); void (*down) /* Called when fsm leaves OPENED state */ __P((fsm *)); void (*starting) /* Called when we want the lower layer */ __P((fsm *)); void (*finished) /* Called when we dont want the lower layer */ __P((fsm *)); void (*protreject) /