/* ====================================================================
 * Copyright (c) 1996-1998 The Apache Group.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Group and was originally based
 * on public domain software written at the National Center for
 * Supercomputing Applications, University of Illinois, Urbana-Champaign.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 */

#ifndef MOD_PROXY_H
#define MOD_PROXY_H 

/*
 * Main include file for the Apache proxy
 */

/*

   Note that the Explain() stuff is not yet complete.
   Also note numerous FIXMEs and CHECKMEs which should be eliminated.

   If TESTING is set, then garbage collection doesn't delete ... probably a good
   idea when hacking.

   This code is still experimental!

   Things to do:

   1. Make it garbage collect in the background, not while someone is waiting for
   a response!

   2. Check the logic thoroughly.

   3. Empty directories are only removed the next time round (but this does avoid
   two passes). Consider doing them the first time round.

   Ben Laurie <ben@algroup.co.uk> 30 Mar 96

   More things to do:

   0. Code cleanup (ongoing)

   1. add 230 response output for ftp now that it works

   2. Make the ftp proxy transparent, also same with (future) gopher & wais

   3. Use protocol handler struct a la Apache module handlers (Dirk van Gulik)

   4. Use a cache expiry database for more efficient GC (Jeremy Wohl)

   5. Bulletproof GC against SIGALRM

   Chuck Murcko <chuck@topsail.org> 15 April 1997

 */

#define TESTING	0
#undef EXPLAIN

#include "httpd.h"
#include "http_config.h"
#include "http_protocol.h"

#include "explain.h"

extern module MODULE_VAR_EXPORT proxy_module;


/* for proxy_canonenc() */
enum enctype {
    enc_path, enc_search, enc_user, enc_fpath, enc_parm
};

#define HDR_APP (0)		/* append header, for proxy_add_header() */
#define HDR_REP (1)		/* replace header, for proxy_add_header() */

/* number of characters in the hash */
#define HASH_LEN (22*2)

/* maximum  'CacheDirLevels*CacheDirLength' value */
#define CACHEFILE_LEN 20	/* must be less than HASH_LEN/2 */

#ifdef CHARSET_EBCDIC
#define CRLF   "\r\n"
#else /*CHARSET_EBCDIC*/
#define CRLF   "\015\012"
#endif /*CHARSET_EBCDIC*/


#define	SEC_ONE_DAY		86400	/* one day, in seconds */
#define	SEC_ONE_HR		3600	/* one hour, in seconds */

#define	DEFAULT_FTP_DATA_PORT	20
#define	DEFAULT_FTP_PORT	21
#define	DEFAULT_GOPHER_PORT	70
#define	DEFAULT_NNTP_PORT	119
#define	DEFAULT_WAIS_PORT	210
#define	DEFAULT_HTTPS_PORT	443
#define	DEFAULT_SNEWS_PORT	563
#define	DEFAULT_PROSPERO_PORT	1525	/* WARNING: conflict w/Oracle */

/* Some WWW schemes and their default ports; this is basically /etc/services */
struct proxy_services {
    const char *scheme;
    int port;
};

/* static information about a remote proxy */
struct proxy_remote {
    const char *scheme;		/* the schemes handled by this proxy, or '*' */
    const char *protocol;	/* the scheme used to talk to this proxy */
    const char *hostname;	/* the hostname of this proxy */
    int port;			/* the port for this proxy */
};

struct proxy_alias {
    char *real;
    char *fake;
};

struct dirconn_entry {
    char *name;
    struct in_addr addr, mask;
    struct hostent *hostentry;
    int (*matcher) (struct dirconn_entry * This, request_rec *r);
};

struct noproxy_entry {
    char *name;
    struct in_addr addr;
};

struct nocache_entry {
    char *name;
    struct in_addr addr;
};

#define DEFAULT_CACHE_SPACE 5
#define DEFAULT_CACHE_MAXEXPIRE SEC_ONE_DAY
#define DEFAULT_CACHE_EXPIRE    SEC_ONE_HR
#define DEFAULT_CACHE_LMFACTOR (0.1)
#define DEFAULT_CACHE_COMPLETION (0.9)

/* static information about the local cache */
struct cache_conf {
    const char *root;		/* the location of the cache directory */
    off_t space;			/* Maximum cache size (in 1024 bytes) */
    time_t maxexpire;		/* Maximum time to keep cached files in secs */
    time_t defaultexpire;	/* default time to keep cached file in secs */
    double lmfactor;		/* factor for estimating expires date */
    time_t gcinterval;		/* garbage collection interval, in seconds */
    int dirlevels;		/* Number of levels of subdirectories */
    int dirlength;		/* Length of subdirectory names */
    float cache_completion;	/* Force cache completion after this point */
};

typedef struct {
    struct cache_conf cache;	/* cache configuration */
    array_header *proxies;
    array_header *aliases;
    array_header *raliases;
    array_header *noproxies;
    array_header *dirconn;
    array_header *nocaches;
    array_header *allowed_connect_ports;
    char *domain;		/* domain name to use in absence of a domain name in the request */
    int req;			/* true if proxy requests are enabled */
    enum {
      via_off,
      via_on,
      via_block,
      via_full
    } viaopt;                   /* how to deal with proxy Via: headers */
    size_t recv_buffer_size;
} proxy_server_conf;

struct hdr_entry {
    const char *field;
    const char *value;
};

/* caching information about a request */
typedef struct {
    request_rec *req;		/* the request */
    char *url;			/* the URL requested */
    char *filename;		/* name of the cache file, or NULL if no cache */
    char *tempfile;		/* name of the temporary file, of NULL if not caching */
    time_t ims;			/* if-modified-since date of request; -1 if no header */
    BUFF *fp;			/* the cache file descriptor if the file is cached
				   and may be returned, or NULL if the file is
				   not cached (or must be reloaded) */
    time_t expire;		/* calculated expire date of cached entity */
    time_t lmod;		/* last-modified date of cached entity */
    time_t date;		/* the date the cached file was last touched */
    int version;		/* update count of the file */
    off_t len;			/* content length */
    char *protocol;		/* Protocol, and major/minor number, e.g. HTTP/1.1 */
    int status;			/* the status of the cached file */
    unsigned int written;	/* total *content* bytes written to cache */
    float cache_completion;	/* specific to this request */
    char *resp_line;		/* the whole status like (protocol, code + message) */
    table *hdrs;		/* the HTTP headers of the file */
} cache_req;

/* Additional information passed to the function called by ap_table_do() */
struct tbl_do_args {
    request_rec *req;
    cache_req *cache;
};

/* Function prototypes */

/* proxy_cache.c */

void ap_proxy_cache_tidy(cache_req *c);
int ap_proxy_cache_check(request_rec *r, char *url, struct cache_conf *conf,
		      cache_req **cr);
int ap_proxy_cache_update(cache_req *c, table *resp_hdrs,
		       const int is_HTTP1, int nocache);
void ap_proxy_garbage_coll(request_rec *r);

/* proxy_connect.c */

int ap_proxy_connect_handler(request_rec *r, cache_req *c, char *url,
			  const char *proxyhost, int proxyport);

/* proxy_ftp.c */

int ap_proxy_ftp_canon(request_rec *r, char *url);
int ap_proxy_ftp_handler(request_rec *r, cache_req *c, char *url);

/* proxy_http.c */

int ap_proxy_http_canon(request_rec *r, char *url, const char *scheme,
		     int def_port);
int ap_proxy_http_handler(request_rec *r, cache_req *c, char *url,
		       const char *proxyhost, int proxyport);

/* proxy_util.c */

int ap_proxy_hex2c(const char *x);
void ap_proxy_c2hex(int ch, char *x);
char *ap_proxy_canonenc(pool *p, const char *x, int len, enum enctype t,
		     int isenc);
char *ap_proxy_canon_netloc(pool *p, char **const urlp, char **userp,
			 char **passwordp, char **hostp, int *port);
const char *ap_proxy_date_canon(pool *p, const char *x);
table *ap_proxy_read_headers(request_rec *r, char *buffer, int size, BUFF *f);
long int ap_proxy_send_fb(BUFF *f, request_rec *r, cache_req *c);
void ap_proxy_send_headers(request_rec *r, const char *respline, table *hdrs);
int ap_proxy_liststr(const char *list, const char *val);
void ap_proxy_hash(const char *it, char *val, int ndepth, int nlength);
int ap_proxy_hex2sec(const char *x);
void ap_proxy_sec2hex(int t, char *y);
cache_req *ap_proxy_cache_error(cache_req *r);
int ap_proxyerror(request_rec *r, const char *message);
const char *ap_proxy_host2addr(const char *host, struct hostent *reqhp);
int ap_proxy_is_ipaddr(struct dirconn_entry *This, pool *p);
int ap_proxy_is_domainname(struct dirconn_entry *This, pool *p);
int ap_proxy_is_hostname(struct dirconn_entry *This, pool *p);
int ap_proxy_is_word(struct dirconn_entry *This, pool *p);
int ap_proxy_doconnect(int sock, struct sockaddr_in *addr, request_rec *r);
int ap_proxy_garbage_init(server_rec *, pool *);
/* This function is called by ap_table_do() for all header lines */
int ap_proxy_send_hdr_line(void *p, const char *key, const char *value);
unsigned ap_proxy_bputs2(const char *data, BUFF *client, cache_req *cache);

#endif /*MOD_PROXY_H*/
