typedef struct {
int channels;
int maxbufsize;
unsigned long features;
unsigned short hl_hdrlen;
void (*rcvcallb)(int, int, u_char*, int);
void (*rcvcallb_skb)(int, int, struct sk_buff *);
int (*statcallb)(isdn_ctrl*);
int (*command)(isdn_ctrl*);
int (*writebuf)(int, int, u_char*, int, int);
int (*writebuf_skb)(int, int, struct sk_buff *);
int (*writecmd)(u_char*, int, int, int, int);
int (*readstat)(u_char*, int, int, int, int);
char id[20];
} isdn_if;