mod_proxy.h

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/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef MOD_PROXY_H
#define MOD_PROXY_H 

/**
 * @file  mod_proxy.h
 * @brief Proxy Extension Module for Apache
 *
 * @defgroup MOD_PROXY mod_proxy
 * @ingroup  APACHE_MODS
 * @{
 */

/*

   Also note numerous FIXMEs and CHECKMEs which should be eliminated.

   This code is once again experimental!

   Things to do:

   1. Make it completely work (for FTP too)

   2. HTTP/1.1

   Chuck Murcko <[e-mail]> 02-06-01

 */

#define CORE_PRIVATE

#include "apr_hooks.h"
#include "apr.h"
#include "apr_lib.h"
#include "apr_strings.h"
#include "apr_buckets.h"
#include "apr_md5.h"
#include "apr_network_io.h"
#include "apr_pools.h"
#include "apr_strings.h"
#include "apr_uri.h"
#include "apr_date.h"
#include "apr_strmatch.h"
#include "apr_fnmatch.h"
#include "apr_reslist.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"

#include "httpd.h"
#include "http_config.h"
#include "ap_config.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_request.h"
#include "http_vhost.h"
#include "http_main.h"
#include "http_log.h"
#include "http_connection.h"
#include "util_filter.h"
#include "util_ebcdic.h"
#include "ap_provider.h"

#if APR_HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if APR_HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

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

#if APR_CHARSET_EBCDIC
#define CRLF   "\r\n"
#else /*APR_CHARSET_EBCDIC*/
#define CRLF   "\015\012"
#endif /*APR_CHARSET_EBCDIC*/

/* default Max-Forwards header setting */
#define DEFAULT_MAX_FORWARDS    10

/* 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 */
    apr_port_t  port;       /* the port for this proxy */
    ap_regex_t *regexp;        /* compiled regex (if any) for the remote */
    int use_regex;          /* simple boolean. True if we have a regex pattern */
};

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

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

struct noproxy_entry {
    const char *name;
    struct apr_sockaddr_t *addr;
};

typedef struct proxy_balancer  proxy_balancer;
typedef struct proxy_worker    proxy_worker;
typedef struct proxy_conn_pool proxy_conn_pool;
typedef struct proxy_balancer_method proxy_balancer_method;

typedef struct {
    apr_array_header_t *proxies;
    apr_array_header_t *sec_proxy;
    apr_array_header_t *aliases;
    apr_array_header_t *noproxies;
    apr_array_header_t *dirconn;
    apr_array_header_t *allowed_connect_ports;
    apr_array_header_t *workers;
    apr_array_header_t *balancers;
    proxy_worker       *forward;    /* forward proxy worker */
    proxy_worker       *reverse;    /* reverse "module-driven" proxy worker */
    const char *domain;     /* domain name to use in absence of a domain name in the request */
    int req;                /* true if proxy requests are enabled */
    char req_set;
    enum {
      via_off,
      via_on,
      via_block,
      via_full
    } viaopt;                   /* how to deal with proxy Via: headers */
    char viaopt_set;
    apr_size_t recv_buffer_size;
    char recv_buffer_size_set;
    apr_size_t io_buffer_size;
    char io_buffer_size_set;
    long maxfwd;
    char maxfwd_set;
    /** 
     * the following setting masks the error page
     * returned from the 'proxied server' and just 
     * forwards the status code upwards.
     * This allows the main server (us) to generate
     * the error page, (so it will look like a error
     * returned from the rest of the system 
     */
    int error_override;
    int error_override_set;
    int preserve_host;
    int preserve_host_set;
    apr_interval_time_t timeout;
    char timeout_set;
    enum {
      bad_error,
      bad_ignore,
      bad_body
    } badopt;                   /* how to deal with bad headers */
    char badopt_set;
/* putting new stuff on the end maximises binary back-compatibility.
 * the strmatch_patterns are really a const just to have a
 * case-independent strstr.
 */
    enum {
        status_off,
        status_on,
        status_full
    } proxy_status;             /* Status display options */
    char proxy_status_set;
    apr_pool_t *pool;           /* Pool used for allocating this struct */
} proxy_server_conf;


typedef struct {
    const char *p;            /* The path */
    int         p_is_fnmatch; /* Is this path an fnmatch candidate? */
    ap_regex_t  *r;            /* Is this a regex? */

/* ProxyPassReverse and friends are documented as working inside
 * <Location>.  But in fact they never have done in the case of
 * more than one <Location>, because the server_conf can't see it.
 * We need to move them to the per-dir config.
 * Discussed in February:
 * http://marc.theaimsgroup.com/?l=apache-httpd-dev&m=110726027118798&w=2
 */
    apr_array_header_t *raliases;
    apr_array_header_t* cookie_paths;
    apr_array_header_t* cookie_domains;
    const apr_strmatch_pattern* cookie_path_str;
    const apr_strmatch_pattern* cookie_domain_str;
} proxy_dir_conf;

typedef struct {
    conn_rec     *connection;
    const char   *hostname;
    apr_port_t   port;
    int          is_ssl;
    apr_pool_t   *pool;     /* Subpool used for creating socket */
    apr_socket_t *sock;     /* Connection socket */
    apr_sockaddr_t *addr;   /* Preparsed remote address info */
    apr_uint32_t flags;     /* Conection flags */
    int          close;     /* Close 'this' connection */
    int          close_on_recycle; /* Close the connection when returning to pool */
    proxy_worker *worker;   /* Connection pool this connection belogns to */
    void         *data;     /* per scheme connection data */
#if APR_HAS_THREADS
    int          inreslist; /* connection in apr_reslist? */
#endif
} proxy_conn_rec;

typedef struct {
        float cache_completion; /* completion percentage */
        int content_length; /* length of the content */
} proxy_completion;

/* Connection pool */
struct proxy_conn_pool {
    apr_pool_t     *pool;   /* The pool used in constructor and destructor calls */
    apr_sockaddr_t *addr;   /* Preparsed remote address info */
#if APR_HAS_THREADS
    apr_reslist_t  *res;    /* Connection resource list */
#endif
    proxy_conn_rec *conn;   /* Single connection for prefork mpm's */
};

/* woker status flags */
#define PROXY_WORKER_INITIALIZED    0x0001
#define PROXY_WORKER_IGNORE_ERRORS  0x0002
#define PROXY_WORKER_IN_SHUTDOWN    0x0010
#define PROXY_WORKER_DISABLED       0x0020
#define PROXY_WORKER_STOPPED        0x0040
#define PROXY_WORKER_IN_ERROR       0x0080

#define PROXY_WORKER_IS_USABLE(f)   (!((f)->s->status & 0x00F0))

/* default worker retry timeout in seconds */
#define PROXY_WORKER_DEFAULT_RETRY  60
#define PROXY_WORKER_MAX_ROUTE_SIZ  63

/* Runtime worker status informations. Shared in scoreboard */
typedef struct {
    int             status;
    apr_time_t      error_time; /* time of the last error */
    int             retries;    /* number of retries on this worker */
    int             lbstatus;   /* Current lbstatus */
    int             lbfactor;   /* dynamic lbfactor */
    apr_off_t       transferred;/* Number of bytes transferred to remote */
    apr_off_t       read;       /* Number of bytes read from remote */
    apr_size_t      elected;    /* Number of times the worker was elected */
    char            route[PROXY_WORKER_MAX_ROUTE_SIZ+1];
    char            redirect[PROXY_WORKER_MAX_ROUTE_SIZ+1];
    void            *context;   /* general purpose storage */
} proxy_worker_stat;

/* Worker configuration */
struct proxy_worker {
    int             id;         /* scoreboard id */
    apr_interval_time_t retry;  /* retry interval */
    int             lbfactor;   /* initial load balancing factor */
    const char      *name;
    const char      *scheme;    /* scheme to use ajp|http|https */
    const char      *hostname;  /* remote backend address */
    const char      *route;     /* balancing route */
    const char      *redirect;  /* temporary balancing redirection route */
    int             status;     /* temporary worker status */
    apr_port_t      port;
    int             min;        /* Desired minimum number of available connections */
    int             smax;       /* Soft maximum on the total number of connections */
    int             hmax;       /* Hard maximum on the total number of connections */
    apr_interval_time_t ttl;    /* maximum amount of time in seconds a connection
                                 * may be available while exceeding the soft limit */
    apr_interval_time_t timeout; /* connection timeout */
    char                timeout_set;
    apr_interval_time_t acquire; /* acquire timeout when the maximum number of connections is exceeded */
    char                acquire_set;
    apr_size_t          recv_buffer_size;
    char                recv_buffer_size_set;
    apr_size_t          io_buffer_size;
    char                io_buffer_size_set;
    char                keepalive;
    char                keepalive_set;
    proxy_conn_pool     *cp;        /* Connection pool to use */
    proxy_worker_stat   *s;         /* Shared data */
    void                *opaque;    /* per scheme worker data */
    int                 is_address_reusable;
#if APR_HAS_THREADS
    apr_thread_mutex_t  *mutex;  /* Thread lock for updating address cache */
#endif
    void                *context;   /* general purpose storage */
    enum {
         flush_off,
         flush_on,
         flush_auto
    } flush_packets;           /* control AJP flushing */
    int                 flush_wait;  /* poll wait time in microseconds if flush_auto */
};

/*
 * Wait 10000 microseconds to find out if more data is currently
 * available at the backend. Just an arbitrary choose.
 */
#define PROXY_FLUSH_WAIT 10000

struct proxy_balancer {
    apr_array_header_t *workers; /* array of proxy_workers */
    const char *name;            /* name of the load balancer */
    const char *sticky;          /* sticky session identifier */
    int         sticky_force;    /* Disable failover for sticky sessions */
    apr_interval_time_t timeout; /* Timeout for waiting on free connection */
    int                 max_attempts; /* Number of attempts before failing */
    char                max_attempts_set;
    proxy_balancer_method *lbmethod;

    /* XXX: Perhaps we will need the proc mutex too.
     * Altrough we are only using arithmetic operations
     * it may lead to a incorrect calculations.
     * For now use only the thread mutex.
     */
#if APR_HAS_THREADS
    apr_thread_mutex_t  *mutex;  /* Thread lock for updating lb params */
#endif
    void            *context;   /* general purpose storage */
};

struct proxy_balancer_method {
    const char *name;            /* name of the load balancer method*/
    proxy_worker *(*finder)(proxy_balancer *balancer,
                            request_rec *r);
    void            *context;   /* general purpose storage */
};

#if APR_HAS_THREADS
#define PROXY_THREAD_LOCK(x)      apr_thread_mutex_lock((x)->mutex)
#define PROXY_THREAD_UNLOCK(x)    apr_thread_mutex_unlock((x)->mutex)
#else
#define PROXY_THREAD_LOCK(x)      APR_SUCCESS
#define PROXY_THREAD_UNLOCK(x)    APR_SUCCESS
#endif

/* hooks */

/* Create a set of PROXY_DECLARE(type), PROXY_DECLARE_NONSTD(type) and 
 * PROXY_DECLARE_DATA with appropriate export and import tags for the platform
 */