 /*
  * @(#) tcpd.h 1.3 95/01/08 21:07:59
  * 
  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
  */

/* Structure to describe one communications endpoint. */

#define STRING_LENGTH	128		/* hosts, users, processes */

struct host_info {
    char    name[STRING_LENGTH];	/* access via eval_hostname(host) */
    char    addr[STRING_LENGTH];	/* access via eval_hostaddr(host) */
    struct sockaddr_in *sin;		/* socket address or 0 */
    struct t_unitdata *unit;		/* TLI transport address or 0 */
    struct request_info *request;	/* for shared information */
};

/* Structure to describe what we know about a service request. */

struct request_info {
    int     fd;				/* socket handle */
    char    user[STRING_LENGTH];	/* access via eval_user(request) */
    char    daemon[STRING_LENGTH];	/* access via eval_daemon(request) */
    char    pid[10];			/* access via eval_pid(request) */
    struct host_info client[1];		/* client endpoint info */
    struct host_info server[1];		/* server endpoint info */
    void  (*sink) ();			/* datagram sink function or 0 */
    void  (*hostname) ();		/* address to printable hostname */
    void  (*hostaddr) ();		/* address to printable address */
    void  (*cleanup) ();		/* cleanup function or 0 */
    struct netconfig *config;		/* netdir handle */
};

/* Common string operations. Less clutter should be more readable. */

#define STRN_CPY(d,s,l)	{ strncpy((d),(s),(l)); (d)[(l)-1] = 0; }

#define STRN_EQ(x,y,l)	(strncasecmp((x),(y),(l)) == 0)
#define STRN_NE(x,y,l)	(strncasecmp((x),(y),(l)) != 0)
#define STR_EQ(x,y)	(strcasecmp((x),(y)) == 0)
#define STR_NE(x,y)	(strcasecmp((x),(y)) != 0)

 /*
  * Initially, all above strings have the empty value. Information that
  * cannot be determined at runtime is set to "unknown", so that we can
  * distinguish between `unavailable' and `not yet looked up'. A hostname
  * that we do not believe in is set to "paranoid".
  */

#define STRING_UNKNOWN	"unknown"	/* lookup failed */
#define STRING_PARANOID	"paranoid"	/* hostname conflict */

extern char unknown[];
extern char paranoid[];

#define HOSTNAME_KNOWN(s) (STR_NE((s),unknown) && STR_NE((s),paranoid))

#define NOT_INADDR(s) (s[strspn(s,"01234567890./")] != 0)

/* Global functions. */

#if defined(TLI) || defined(PTX) || defined(TLI_SEQUENT)
extern void fromhost();			/* get/validate client host info */
#else
#define fromhost sock_host		/* no TLI support needed */
#endif

extern int hosts_access();		/* access control */
extern void shell_cmd();		/* execute shell command */
extern char *percent_x();		/* do %<char> expansion */
extern void rfc931();			/* client name from RFC 931 daemon */
extern void clean_exit();		/* clean up and exit */
extern void refuse();			/* clean up and exit */
extern char *xgets();			/* fgets() on steroids */
extern char *split_at();		/* strchr() and split */
extern unsigned long dot_quad_addr();	/* restricted inet_addr() */

/* Global variables. */

extern int allow_severity;		/* for connection logging */
extern int deny_severity;		/* for connection logging */
extern char *hosts_allow_table;		/* for verification mode redirection */
extern char *hosts_deny_table;		/* for verification mode redirection */
extern int hosts_access_verbose;	/* for verbose matching mode */
extern int rfc931_timeout;		/* user lookup timeout */

 /*
  * Routines for controlled initialization and update of request structure
  * attributes. Each attribute has its own key.
  */

#ifdef __STDC__
extern struct request_info *request_init(struct request_info *,...);
extern struct request_info *request_set(struct request_info *,...);
#else
extern struct request_info *request_init();	/* initialize request */
extern struct request_info *request_set();	/* update request structure */
#endif

#define RQ_FILE		1		/* file descriptor */
#define RQ_DAEMON	2		/* server process (argv[0]) */
#define RQ_USER		3		/* client user name */
#define RQ_CLIENT_NAME	4		/* client host name */
#define RQ_CLIENT_ADDR	5		/* client host address */
#define RQ_CLIENT_SIN	6		/* client endpoint (internal) */
#define RQ_SERVER_NAME	7		/* server host name */
#define RQ_SERVER_ADDR	8		/* server host address */
#define RQ_SERVER_SIN	9		/* server endpoint (internal) */

 /*
  * Routines for delayed evaluation of request attributes. Each attribute
  * type has its own access method. The trivial ones are implemented by
  * macros. The other ones are wrappers around the transport-specific host
  * name, address, and client user lookup methods. The request_info and
  * host_info structures serve as caches for the lookup results.
  */

extern char *eval_user();		/* client user */
extern char *eval_hostname();		/* printable hostname */
extern char *eval_hostaddr();		/* printable host address */
extern char *eval_hostinfo();		/* host name or address */
extern char *eval_client();		/* whatever is available */
extern char *eval_server();		/* whatever is available */
#define eval_daemon(r)	((r)->daemon)	/* daemon process name */
#define eval_pid(r)	((r)->pid)	/* process id */

/* Socket-specific methods, including DNS hostname lookups. */

extern void sock_host();		/* look up endpoint addresses */
extern void sock_hostname();		/* translate address to hostname */
extern void sock_hostaddr();		/* address to printable address */
#define sock_methods(r) \
	{ (r)->hostname = sock_hostname; (r)->hostaddr = sock_hostaddr; }

/* The System V Transport-Level Interface (TLI) interface. */

#if defined(TLI) || defined(PTX) || defined(TLI_SEQUENT)
extern void tli_host();			/* look up endpoint addresses etc. */
#endif

 /*
  * Problem reporting interface. Additional file/line context is reported
  * when available. The jump buffer (tcpd_buf) is not declared here, or
  * everyone would have to include <setjmp.h>.
  */

#ifdef __STDC__
extern void tcpd_warn(char *, ...);	/* report problem and proceed */
extern void tcpd_jump(char *, ...);	/* report problem and jump */
#else
extern void tcpd_warn();
extern void tcpd_jump();
#endif

struct tcpd_context {
    char   *file;			/* current file */
    int     line;			/* current line */
};
extern struct tcpd_context tcpd_context;

 /*
  * While processing access control rules, error conditions are handled by
  * jumping back into the hosts_access() routine. This is cleaner than
  * checking the return value of each and every silly little function. The
  * (-1) returns are here because zero is already taken by longjmp().
  */

#define AC_PERMIT	1		/* permit access */
#define AC_DENY		(-1)		/* deny_access */
#define AC_ERROR	AC_DENY		/* XXX */

 /*
  * In verification mode an option function should just say what it would do,
  * instead of really doing it. An option function that would not return
  * should clear the dry_run flag to inform the caller of this unusual
  * behavior.
  */

extern void process_options();		/* execute options */
extern int dry_run;			/* verification flag */

/* Bug workarounds. */

#ifdef INET_ADDR_BUG			/* inet_addr() returns struct */
#define inet_addr fix_inet_addr
extern long fix_inet_addr();
#endif

#ifdef BROKEN_FGETS			/* partial reads from sockets */
#define fgets fix_fgets
extern char *fix_fgets();
#endif

#ifdef RECVFROM_BUG			/* no address family info */
#define recvfrom fix_recvfrom
extern int fix_recvfrom();
#endif

#ifdef GETPEERNAME_BUG			/* claims success with UDP */
#define getpeername fix_getpeername
extern int fix_getpeername();
#endif

#ifdef SOLARIS_24_GETHOSTBYNAME_BUG	/* lists addresses as aliases */
#define gethostbyname fix_gethostbyname
extern struct hostent *fix_gethostbyname();
#endif
