/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/**
 * @file ajp.h
 * @brief Apache Jserv Protocol
 *
 * @defgroup AJP_defines mod_proxy AJP definitions
 * @ingroup  APACHE_INTERNAL
 * @{
 */

#ifndef AJP_H
#define AJP_H

#include "apr_version.h"
#include "apr.h"

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

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

#define AJP13_DEF_HOST "127.0.0.1"
#ifdef NETWARE
#define AJP13_DEF_PORT 9009     /* default to 9009 since 8009 is used by OS */
#else
#define AJP13_DEF_PORT 8009
#endif

/* The following environment variables match mod_ssl! */
#define AJP13_HTTPS_INDICATOR           "HTTPS"
#define AJP13_SSL_PROTOCOL_INDICATOR    "SSL_PROTOCOL"
#define AJP13_SSL_CLIENT_CERT_INDICATOR "SSL_CLIENT_CERT"
#define AJP13_SSL_CIPHER_INDICATOR      "SSL_CIPHER"
#define AJP13_SSL_SESSION_INDICATOR     "SSL_SESSION_ID"
#define AJP13_SSL_KEY_SIZE_INDICATOR    "SSL_CIPHER_USEKEYSIZE"

#ifdef AJP_USE_HTTPD_WRAP
#include "httpd_wrap.h"
#else
#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_main.h"
#include "http_log.h"
#endif

#include "mod_proxy.h"
#include "util_ebcdic.h"

/** AJP Specific error codes
 */
/** Buffer overflow exception */
#define AJP_EOVERFLOW           (APR_OS_START_USERERR + 1)
/** Destination Buffer is to small */
#define AJP_ETOSMALL            (APR_OS_START_USERERR + 2)
/** Invalid input parameters */
#define AJP_EINVAL              (APR_OS_START_USERERR + 3)
/** Bad message signature */
#define AJP_EBAD_SIGNATURE      (APR_OS_START_USERERR + 4)
/** Incoming message too bg */
#define AJP_ETOBIG              (APR_OS_START_USERERR + 5)
/** Missing message header */
#define AJP_ENO_HEADER          (APR_OS_START_USERERR + 6)
/** Bad message header */
#define AJP_EBAD_HEADER         (APR_OS_START_USERERR + 7)
/** Bad message */
#define AJP_EBAD_MESSAGE        (APR_OS_START_USERERR + 8)
/** Cant log via AJP14 */
#define AJP_ELOGFAIL            (APR_OS_START_USERERR + 9)


/** A structure that represents ajp message */
typedef struct ajp_msg ajp_msg_t;

/** A structure that represents ajp message */
struct ajp_msg
{
    /** The buffer holding a AJP message */
    apr_byte_t  *buf;
    /** The length of AJP message header (defaults to AJP_HEADER_LEN) */
    apr_size_t  header_len;
    /** The length of AJP message */
    apr_size_t  len;
    /** The current read position */
    apr_size_t  pos;
    /** Flag indicating the origing of the message */
    int         server_side;
    /** The size of the buffer */
    apr_size_t max_size;
};

/**
 * Signature for the messages sent from Apache to tomcat
 */
#define AJP13_WS_HEADER             0x1234
#define AJP_HEADER_LEN              4
#define AJP_HEADER_SZ_LEN           2
#define AJP_HEADER_SZ               6
#define AJP_MSG_BUFFER_SZ           8192
#define AJP_MAX_BUFFER_SZ           65536
#define AJP13_MAX_SEND_BODY_SZ      (AJP_MAX_BUFFER_SZ - AJP_HEADER_SZ)
#define AJP_PING_PONG_SZ            128

/** Send a request from web server to container*/
#define CMD_AJP13_FORWARD_REQUEST   (unsigned char)2
/** Write a body chunk from the servlet container to the web server */
#define CMD_AJP13_SEND_BODY_CHUNK   (unsigned char)3
/** Send response headers from the servlet container to the web server. */
#define CMD_AJP13_SEND_HEADERS      (unsigned char)4
/** Marks the end of response. */
#define CMD_AJP13_END_RESPONSE      (unsigned char)5
/** Get further data from the web server if it hasn't all been transferred yet. */
#define CMD_AJP13_GET_BODY_CHUNK    (unsigned char)6
/** The web server asks the container to shut itself down. */
#define CMD_AJP13_SHUTDOWN          (unsigned char)7
/** Webserver ask container to take control (logon phase) */
#define CMD_AJP13_PING              (unsigned char)8
/** Container response to cping request */
#define CMD_AJP13_CPONG             (unsigned char)9
/** Webserver check if container is alive, since container should respond by cpong */
#define CMD_AJP13_CPING             (unsigned char)10

/** @} */

/**
 * @defgroup AJP_api AJP API functions
 * @ingroup  MOD_PROXY
 * @{
 */
/**
 * Check a new AJP Message by looking at signature and return its size
 *
 * @param msg       AJP Message to check
 * @param len       Pointer to returned len
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_check_header(ajp_msg_t *msg, apr_size_t *len);

/**
 * Reset an AJP Message
 *
 * @param msg       AJP Message to reset
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_reset(ajp_msg_t *msg);

/**
 * Reuse an AJP Message
 *
 * @param msg       AJP Message to reuse
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_reuse(ajp_msg_t *msg);

/**
 * Mark the end of an AJP Message
 *
 * @param msg       AJP Message to end
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_end(ajp_msg_t *msg);

/**
 * Add an unsigned 32bits value to AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param value     value to add to AJP Message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_append_uint32(ajp_msg_t *msg, apr_uint32_t value);

/**
 * Add an unsigned 16bits value to AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param value     value to add to AJP Message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_append_uint16(ajp_msg_t *msg, apr_uint16_t value);

/**
 * Add an unsigned 8bits value to AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param value     value to add to AJP Message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_append_uint8(ajp_msg_t *msg, apr_byte_t value);

/**
 *  Add a String in AJP message, and transform the String in ASCII
 *  if convert is set and we're on an EBCDIC machine
 *
 * @param msg       AJP Message to get value from
 * @param value     Pointer to String
 * @param convert   When set told to convert String to ASCII
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_append_string_ex(ajp_msg_t *msg, const char *value,
                                      int convert);
/**
 *  Add a String in AJP message, and transform
 *  the String in ASCII if we're on an EBCDIC machine
 */
#define ajp_msg_append_string(m, v) ajp_msg_append_string_ex(m, v, 1)

/**
 *  Add a String in AJP message.
 */
#define ajp_msg_append_string_ascii(m, v) ajp_msg_append_string_ex(m, v, 0)

/**
 * Add a Byte array to AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param value     Pointer to Byte array
 * @param valuelen  Byte array len
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_append_bytes(ajp_msg_t *msg, const apr_byte_t *value,
                                  apr_size_t valuelen);

/**
 * Get a 32bits unsigned value from AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_get_uint32(ajp_msg_t *msg, apr_uint32_t *rvalue);

/**
 * Get a 16bits unsigned value from AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_get_uint16(ajp_msg_t *msg, apr_uint16_t *rvalue);

/**
 * Peek a 16bits unsigned value from AJP Message, position in message
 * is not updated
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_peek_uint16(ajp_msg_t *msg, apr_uint16_t *rvalue);

/**
 * Get a 8bits unsigned value from AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_get_uint8(ajp_msg_t *msg, apr_byte_t *rvalue);

/**
 * Peek a 8bits unsigned value from AJP Message, position in message
 * is not updated
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_peek_uint8(ajp_msg_t *msg, apr_byte_t *rvalue);

/**
 * Get a String value from AJP Message
 *
 * @param msg       AJP Message to get value from
 * @param rvalue    Pointer where value will be returned
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_get_string(ajp_msg_t *msg, const char **rvalue);


/**
 * Get a Byte array from AJP Message
 *
 * @param msg        AJP Message to get value from
 * @param rvalue     Pointer where value will be returned
 * @param rvalue_len Pointer where Byte array len will be returned
 * @return           APR_SUCCESS or error
 */
apr_status_t ajp_msg_get_bytes(ajp_msg_t *msg, apr_byte_t **rvalue,
                               apr_size_t *rvalue_len);

/**
 * Create an AJP Message from pool
 *
 * @param pool      memory pool to allocate AJP message from
 * @param size      size of the buffer to create
 * @param rmsg      Pointer to newly created AJP message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_create(apr_pool_t *pool, apr_size_t size, ajp_msg_t **rmsg);

/**
 * Recopy an AJP Message to another
 *
 * @param smsg      source AJP message
 * @param dmsg      destination AJP message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_copy(ajp_msg_t *smsg, ajp_msg_t *dmsg);

/**
 * Serialize in an AJP Message a PING command
 *
 * +-----------------------+
 * | PING CMD (1 byte)     |
 * +-----------------------+
 *
 * @param msg       AJP message to put serialized message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_serialize_ping(ajp_msg_t *msg);

/**
 * Serialize in an AJP Message a CPING command
 *
 * +-----------------------+
 * | CPING CMD (1 byte)    |
 * +-----------------------+
 *
 * @param msg      AJP message to put serialized message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_serialize_cping(ajp_msg_t *msg);

/**
 * Dump up to the first 1024 bytes on an AJP Message
 *
 * @param pool      pool to allocate from
 * @param msg       AJP Message to dump
 * @param err       error string to display
 * @param count     the number of bytes to dump
 * @param buf       buffer pointer for dump message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_dump(apr_pool_t *pool, ajp_msg_t *msg, char *err,
                          apr_size_t count, char **buf);

/**
 * Log an AJP message
 *
 * @param r         The current request
 * @param msg       AJP Message to dump
 * @param err       error string to display
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_msg_log(request_rec *r, ajp_msg_t *msg, char *err);

/**
 * Send an AJP message to backend
 *
 * @param sock      backend socket
 * @param msg       AJP message to put serialized message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_ilink_send(apr_socket_t *sock, ajp_msg_t *msg);

/**
 * Receive an AJP message from backend
 *
 * @param sock      backend socket
 * @param msg       AJP message to put serialized message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_ilink_receive(apr_socket_t *sock, ajp_msg_t *msg);

/**
 * Build the ajp header message and send it
 * @param sock      backend socket
 * @param r         current request
 * @param buffsize  max size of the AJP packet.
 * @param uri       requested uri
 * @param secret    authentication secret
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_send_header(apr_socket_t *sock, request_rec *r,
                             apr_size_t buffsize,
                             apr_uri_t *uri,
                             const char *secret);

/**
 * Read the ajp message and return the type of the message.
 * @param sock      backend socket
 * @param r         current request
 * @param buffsize  size of the buffer.
 * @param msg       returned AJP message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_read_header(apr_socket_t *sock,
                             request_rec  *r,
                             apr_size_t buffsize,
                             ajp_msg_t **msg);

/**
 * Allocate a msg to send data
 * @param pool      pool to allocate from
 * @param ptr       data buffer
 * @param len       the length of allocated data buffer
 * @param msg       returned AJP message
 * @return          APR_SUCCESS or error
 */
apr_status_t  ajp_alloc_data_msg(apr_pool_t *pool, char **ptr,
                                 apr_size_t *len, ajp_msg_t **msg);

/**
 * Send the data message
 * @param sock      backend socket
 * @param msg       AJP message to send
 * @param len       AJP message length
 * @return          APR_SUCCESS or error
 */
apr_status_t  ajp_send_data_msg(apr_socket_t *sock,
                                ajp_msg_t *msg, apr_size_t len);

/**
 * Parse the message type
 * @param r         current request
 * @param msg       AJP message
 * @return          AJP message type.
 */
int ajp_parse_type(request_rec  *r, ajp_msg_t *msg);

/**
 * Parse the header message from container
 * @param r         current request
 * @param conf      proxy config
 * @param msg       AJP message
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_parse_header(request_rec *r, proxy_dir_conf *conf,
                              ajp_msg_t *msg);

/**
 * Parse the message body and return data address and length
 * @param r         current request
 * @param msg       AJP message
 * @param len       returned AJP message length
 * @param ptr       returned data
 * @return          APR_SUCCESS or error
 */
apr_status_t  ajp_parse_data(request_rec  *r, ajp_msg_t *msg,
                             apr_uint16_t *len, char **ptr);


/**
 * Check the reuse flag in CMD_AJP13_END_RESPONSE
 * @param r         current request
 * @param msg       AJP message
 * @param reuse     returned reuse flag
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_parse_reuse(request_rec *r, ajp_msg_t *msg,
                             apr_byte_t *reuse);


/**
 * Handle the CPING/CPONG messages
 * @param sock      backend socket
 * @param r         current request
 * @param timeout   time window for receiving cpong reply
 * @return          APR_SUCCESS or error
 */
apr_status_t ajp_handle_cping_cpong(apr_socket_t *sock,
                                    request_rec *r,
                                    apr_interval_time_t timeout);


/**
 * Convert numeric message type into string
 * @param type      AJP message type
 * @return          AJP message type as a string
 */
const char *ajp_type_str(int type);

/** @} */

#endif /* AJP_H */