curl/lib/urldata.h

#ifndef __URLDATA_H
#define __URLDATA_H
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

/* This file is for lib internal stuff */

#include "setup.h"

#define PORT_FTP 21
#define PORT_FTPS 990
#define PORT_TELNET 23
#define PORT_HTTP 80
#define PORT_HTTPS 443
#define PORT_DICT 2628
#define PORT_LDAP 389
#define PORT_LDAPS 636
#define PORT_TFTP 69
#define PORT_SSH 22
#define PORT_IMAP 143
#define PORT_IMAPS 993
#define PORT_POP3 110
#define PORT_POP3S 995
#define PORT_SMTP 25
#define PORT_SMTPS 465 /* sometimes called SSMTP */
#define PORT_RTSP 554
#define PORT_RTMP 1935
#define PORT_RTMPT PORT_HTTP
#define PORT_RTMPS PORT_HTTPS
#define PORT_GOPHER 70

#define DICT_MATCH "/MATCH:"
#define DICT_MATCH2 "/M:"
#define DICT_MATCH3 "/FIND:"
#define DICT_DEFINE "/DEFINE:"
#define DICT_DEFINE2 "/D:"
#define DICT_DEFINE3 "/LOOKUP:"

#define CURL_DEFAULT_USER "anonymous"
#define CURL_DEFAULT_PASSWORD "ftp@example.com"

/* length of longest IPv6 address string including the trailing null */
#define MAX_IPADR_LEN sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")

/* Default FTP/IMAP etc response timeout in milliseconds.
   Symbian OS panics when given a timeout much greater than 1/2 hour.
*/
#define RESP_TIMEOUT (1800*1000)

#include "cookie.h"
#include "formdata.h"

#ifdef USE_SSLEAY
#ifdef USE_OPENSSL
#include "openssl/rsa.h"
#include "openssl/crypto.h"
#include "openssl/x509.h"
#include "openssl/pem.h"
#include "openssl/ssl.h"
#include "openssl/err.h"
#ifdef HAVE_OPENSSL_ENGINE_H
#include <openssl/engine.h>
#endif
#ifdef HAVE_OPENSSL_PKCS12_H
#include <openssl/pkcs12.h>
#endif
#else /* SSLeay-style includes */
#include "rsa.h"
#include "crypto.h"
#include "x509.h"
#include "pem.h"
#include "ssl.h"
#include "err.h"
#ifdef HAVE_OPENSSL_ENGINE_H
#include <engine.h>
#endif
#ifdef HAVE_OPENSSL_PKCS12_H
#include <pkcs12.h>
#endif
#endif /* USE_OPENSSL */
#ifdef USE_GNUTLS
#error Configuration error; cannot use GnuTLS *and* OpenSSL.
#endif
#endif /* USE_SSLEAY */

#ifdef USE_GNUTLS
#include <gnutls/gnutls.h>
#endif

#ifdef USE_POLARSSL
#include <polarssl/havege.h>
#include <polarssl/ssl.h>
#endif

#ifdef USE_NSS
#include <nspr.h>
#include <pk11pub.h>
#endif

#ifdef USE_QSOSSL
#include <qsossl.h>
#endif

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#include "timeval.h"

#ifdef HAVE_ZLIB_H
#include <zlib.h>               /* for content-encoding */
#ifdef __SYMBIAN32__
/* zlib pollutes the namespace with this definition */
#undef WIN32
#endif
#endif

#ifdef USE_ARES
#  if defined(CURL_STATICLIB) && !defined(CARES_STATICLIB) && \
     (defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__))
#    define CARES_STATICLIB
#  endif
#  include <ares.h>
#endif

#include <curl/curl.h>

#include "http_chunks.h" /* for the structs and enum stuff */
#include "hostip.h"
#include "hash.h"
#include "splay.h"

#include "imap.h"
#include "pop3.h"
#include "smtp.h"
#include "ftp.h"
#include "file.h"
#include "ssh.h"
#include "http.h"
#include "rtsp.h"
#include "wildcard.h"

#ifdef HAVE_GSSAPI
# ifdef HAVE_GSSGNU
#  include <gss.h>
# elif defined HAVE_GSSMIT
#  include <gssapi/gssapi.h>
#  include <gssapi/gssapi_generic.h>
# else
#  include <gssapi.h>
# endif
#endif

#ifdef HAVE_LIBSSH2_H
#include <libssh2.h>
#include <libssh2_sftp.h>
#endif /* HAVE_LIBSSH2_H */

/* Download buffer size, keep it fairly big for speed reasons */
#undef BUFSIZE
#define BUFSIZE CURL_MAX_WRITE_SIZE

/* Initial size of the buffer to store headers in, it'll be enlarged in case
   of need. */
#define HEADERSIZE 256

#define CURLEASY_MAGIC_NUMBER 0xc0dedbadU

/* Some convenience macros to get the larger/smaller value out of two given.
   We prefix with CURL to prevent name collisions. */
#define CURLMAX(x,y) ((x)>(y)?(x):(y))
#define CURLMIN(x,y) ((x)<(y)?(x):(y))


#if defined(HAVE_KRB4) || defined(HAVE_GSSAPI)
/* Types needed for krb4/5-ftp connections */
struct krb4buffer {
  void *data;
  size_t size;
  size_t index;
  int eof_flag;
};
enum protection_level {
  prot_none, /* first in list */
  prot_clear,
  prot_safe,
  prot_confidential,
  prot_private,
  prot_cmd,
  prot_last /* last in list */
};
#endif

/* enum for the nonblocking SSL connection state machine */
typedef enum {
  ssl_connect_1,
  ssl_connect_2,
  ssl_connect_2_reading,
  ssl_connect_2_writing,
  ssl_connect_3,
  ssl_connect_done
} ssl_connect_state;

typedef enum {
  ssl_connection_none,
  ssl_connection_negotiating,
  ssl_connection_complete
} ssl_connection_state;

/* struct for data related to each SSL connection */
struct ssl_connect_data {
  /* Use ssl encrypted communications TRUE/FALSE, not necessarily using it atm
     but at least asked to or meaning to use it. See 'state' for the exact
     current state of the connection. */
  bool use;
  ssl_connection_state state;
#ifdef USE_SSLEAY
  /* these ones requires specific SSL-types */
  SSL_CTX* ctx;
  SSL*     handle;
  X509*    server_cert;
  ssl_connect_state connecting_state;
#endif /* USE_SSLEAY */
#ifdef USE_GNUTLS
  gnutls_session session;
  gnutls_certificate_credentials cred;
  ssl_connect_state connecting_state;
#endif /* USE_GNUTLS */
#ifdef USE_POLARSSL
  havege_state hs;
  ssl_context ssl;
  ssl_session ssn;
  int server_fd;
  x509_cert cacert;
  x509_cert clicert;
  x509_crl crl;
  rsa_context rsa;
#endif /* USE_POLARSSL */
#ifdef USE_NSS
  PRFileDesc *handle;
  char *client_nickname;
  struct SessionHandle *data;
#ifdef HAVE_PK11_CREATEGENERICOBJECT
  PK11GenericObject *key;
  PK11GenericObject *cacert[2];
#endif
#endif /* USE_NSS */
#ifdef USE_QSOSSL
  SSLHandle *handle;
#endif /* USE_QSOSSL */
};

struct ssl_config_data {
  long version;          /* what version the client wants to use */
  long certverifyresult; /* result from the certificate verification */
  long verifypeer;       /* set TRUE if this is desired */
  long verifyhost;       /* 0: no verify
                            1: check that CN exists
                            2: CN must match hostname */
  char *CApath;          /* certificate dir (doesn't work on windows) */
  char *CAfile;          /* certificate to verify peer against */
  const char *CRLfile;   /* CRL to check certificate revocation */
  const char *issuercert;/* optional issuer certificate filename */
  char *random_file;     /* path to file containing "random" data */
  char *egdsocket;       /* path to file containing the EGD daemon socket */
  char *cipher_list;     /* list of ciphers to use */
  long numsessions;      /* SSL session id cache size */
  curl_ssl_ctx_callback fsslctx; /* function to initialize ssl ctx */
  void *fsslctxp;        /* parameter for call back */
  bool sessionid;        /* cache session IDs or not */
  bool certinfo;         /* gather lots of certificate info */
};

/* information stored about one single SSL session */
struct curl_ssl_session {
  char *name;       /* host name for which this ID was used */
  void *sessionid;  /* as returned from the SSL layer */
  size_t idsize;    /* if known, otherwise 0 */
  long age;         /* just a number, the higher the more recent */
  unsigned short remote_port; /* remote port to connect to */
  struct ssl_config_data ssl_config; /* setup for this session */
};

/* Struct used for Digest challenge-response authentication */
struct digestdata {
  char *nonce;
  char *cnonce;
  char *realm;
  int algo;
  bool stale; /* set true for re-negotiation */
  char *opaque;
  char *qop;
  char *algorithm;
  int nc; /* nounce count */
};

typedef enum {
  NTLMSTATE_NONE,
  NTLMSTATE_TYPE1,
  NTLMSTATE_TYPE2,
  NTLMSTATE_TYPE3,
  NTLMSTATE_LAST
} curlntlm;

#ifdef USE_WINDOWS_SSPI
#include "curl_sspi.h"
#endif

#if defined(CURL_DOES_CONVERSIONS) && defined(HAVE_ICONV)
#include <iconv.h>
#endif

/* Struct used for NTLM challenge-response authentication */
struct ntlmdata {
  curlntlm state;
#ifdef USE_WINDOWS_SSPI
  CredHandle handle;
  CtxtHandle c_handle;
  SEC_WINNT_AUTH_IDENTITY identity;
  SEC_WINNT_AUTH_IDENTITY *p_identity;
  int has_handles;
  void *type_2;
  int n_type_2;
#else
  unsigned int flags;
  unsigned char nonce[8];
#endif
};

#ifdef HAVE_GSSAPI
struct negotiatedata {
  /* when doing Negotiate we first need to receive an auth token and then we
     need to send our header */
  enum { GSS_AUTHNONE, GSS_AUTHRECV, GSS_AUTHSENT } state;
  bool gss; /* Whether we're processing GSS-Negotiate or Negotiate */
  const char* protocol; /* "GSS-Negotiate" or "Negotiate" */
  OM_uint32 status;
  gss_ctx_id_t context;
  gss_name_t server_name;
  gss_buffer_desc output_token;
};
#endif


/*
 * Boolean values that concerns this connection.
 */
struct ConnectBits {
  bool close; /* if set, we close the connection after this request */
  bool reuse; /* if set, this is a re-used connection */
  bool proxy; /* if set, this transfer is done through a proxy - any type */
  bool httpproxy;    /* if set, this transfer is done through a http proxy */
  bool user_passwd;    /* do we use user+password for this connection? */
  bool proxy_user_passwd; /* user+password for the proxy? */
  bool ipv6_ip; /* we communicate with a remote site specified with pure IPv6
                   IP address */
  bool ipv6;    /* we communicate with a site using an IPv6 address */

  bool do_more; /* this is set TRUE if the ->curl_do_more() function is
                   supposed to be called, after ->curl_do() */

  bool tcpconnect;    /* the TCP layer (or similar) is connected, this is set
                         the first time on the first connect function call */
  bool protoconnstart;/* the protocol layer has STARTED its operation after
                         the TCP layer connect */

  bool retry;         /* this connection is about to get closed and then
                         re-attempted at another connection. */
  bool tunnel_proxy;  /* if CONNECT is used to "tunnel" through the proxy.
                         This is implicit when SSL-protocols are used through
                         proxies, but can also be enabled explicitly by
                         apps */
  bool tunnel_connecting; /* TRUE while we're still waiting for a proxy CONNECT
                           */
  bool authneg;       /* TRUE when the auth phase has started, which means
                         that we are creating a request with an auth header,
                         but it is not the final request in the auth
                         negotiation. */
  bool rewindaftersend;/* TRUE when the sending couldn't be stopped even
                          though it will be discarded. When the whole send
                          operation is done, we must call the data rewind
                          callback. */
  bool ftp_use_epsv;  /* As set with CURLOPT_FTP_USE_EPSV, but if we find out
                         EPSV doesn't work we disable it for the forthcoming
                         requests */

  bool ftp_use_eprt;  /* As set with CURLOPT_FTP_USE_EPRT, but if we find out
                         EPRT doesn't work we disable it for the forthcoming
                         requests */
  bool netrc;         /* name+password provided by netrc */
  bool userpwd_in_url; /* name+password found in url */

  bool done;          /* set to FALSE when Curl_do() is called and set to TRUE
                         when Curl_done() is called, to prevent Curl_done() to
                         get invoked twice when the multi interface is
                         used. */
  bool stream_was_rewound; /* Indicates that the stream was rewound after a
                              request read past the end of its response byte
                              boundary */
  bool proxy_connect_closed; /* set true if a proxy disconnected the
                                connection in a CONNECT request with auth, so
                                that libcurl should reconnect and continue. */
  bool bound; /* set true if bind() has already been done on this socket/
                 connection */
  bool type_set;  /* type= was used in the URL */
};

struct hostname {
  char *rawalloc; /* allocated "raw" version of the name */
  char *encalloc; /* allocated IDN-encoded version of the name */
  char *name;     /* name to use internally, might be encoded, might be raw */
  const char *dispname; /* name to display, as 'name' might be encoded */
};

/*
 * Flags on the keepon member of the Curl_transfer_keeper
 */

#define KEEP_NONE  0
#define KEEP_RECV  (1<<0)     /* there is or may be data to read */
#define KEEP_SEND (1<<1)     /* there is or may be data to write */
#define KEEP_RECV_HOLD (1<<2) /* when set, no reading should be done but there
                                 might still be data to read */
#define KEEP_SEND_HOLD (1<<3) /* when set, no writing should be done but there
                                  might still be data to write */
#define KEEP_RECV_PAUSE (1<<4) /* reading is paused */
#define KEEP_SEND_PAUSE (1<<5) /* writing is paused */

#define KEEP_RECVBITS (KEEP_RECV | KEEP_RECV_HOLD | KEEP_RECV_PAUSE)
#define KEEP_SENDBITS (KEEP_SEND | KEEP_SEND_HOLD | KEEP_SEND_PAUSE)


#ifdef HAVE_LIBZ
typedef enum {
  ZLIB_UNINIT,          /* uninitialized */
  ZLIB_INIT,            /* initialized */
  ZLIB_GZIP_HEADER,     /* reading gzip header */
  ZLIB_GZIP_INFLATING,  /* inflating gzip stream */
  ZLIB_INIT_GZIP        /* initialized in transparent gzip mode */
} zlibInitState;
#endif

#ifdef CURLRES_ASYNCH
struct Curl_async {
  char *hostname;
  int port;
  struct Curl_dns_entry *dns;
  bool done;  /* set TRUE when the lookup is complete */
  int status; /* if done is TRUE, this is the status from the callback */
  void *os_specific;  /* 'struct thread_data' for Windows */
};
#endif

#define FIRSTSOCKET     0
#define SECONDARYSOCKET 1

/* These function pointer types are here only to allow easier typecasting
   within the source when we need to cast between data pointers (such as NULL)
   and function pointers. */
typedef CURLcode (*Curl_do_more_func)(struct connectdata *);
typedef CURLcode (*Curl_done_func)(struct connectdata *, CURLcode, bool);


enum expect100 {
  EXP100_SEND_DATA,           /* enough waiting, just send the body now */
  EXP100_AWAITING_CONTINUE,   /* waiting for the 100 Continue header */
  EXP100_SENDING_REQUEST,     /* still sending the request but will wait for
                                 the 100 header once done with the request */
  EXP100_FAILED               /* used on 417 Expectation Failed */
};

/*
 * Request specific data in the easy handle (SessionHandle).  Previously,
 * these members were on the connectdata struct but since a conn struct may
 * now be shared between different SessionHandles, we store connection-specific
 * data here. This struct only keeps stuff that's interesting for *this*
 * request, as it will be cleared between multiple ones
 */
struct SingleRequest {
  curl_off_t size;        /* -1 if unknown at this point */
  curl_off_t *bytecountp; /* return number of bytes read or NULL */

  curl_off_t maxdownload; /* in bytes, the maximum amount of data to fetch,
                             -1 means unlimited */
  curl_off_t *writebytecountp; /* return number of bytes written or NULL */

  curl_off_t bytecount;         /* total number of bytes read */
  curl_off_t writebytecount;    /* number of bytes written */

  long headerbytecount;         /* only count received headers */
  long deductheadercount; /* this amount of bytes doesn't count when we check
                             if anything has been transfered at the end of a
                             connection. We use this counter to make only a
                             100 reply (without a following second response
                             code) result in a CURLE_GOT_NOTHING error code */

  struct timeval start;         /* transfer started at this time */
  struct timeval now;           /* current time */
  bool header;                  /* incoming data has HTTP header */
  enum {
    HEADER_NORMAL,              /* no bad header at all */
    HEADER_PARTHEADER,          /* part of the chunk is a bad header, the rest
                                   is normal data */
    HEADER_ALLBAD               /* all was believed to be header */
  } badheader;                  /* the header was deemed bad and will be
                                   written as body */
  int headerline;               /* counts header lines to better track the
                                   first one */
  char *hbufp;                  /* points at *end* of header line */
  size_t hbuflen;
  char *str;                    /* within buf */
  char *str_start;              /* within buf */
  char *end_ptr;                /* within buf */
  char *p;                      /* within headerbuff */
  bool content_range;           /* set TRUE if Content-Range: was found */
  curl_off_t offset;            /* possible resume offset read from the
                                   Content-Range: header */
  int httpcode;                 /* error code from the 'HTTP/1.? XXX' or
                                   'RTSP/1.? XXX' line */
  struct timeval start100;      /* time stamp to wait for the 100 code from */
  enum expect100 exp100;        /* expect 100 continue state */

  int content_encoding;         /* What content encoding. sec 3.5, RFC2616. */

#define IDENTITY 0              /* No encoding */
#define DEFLATE 1               /* zlib deflate [RFC 1950 & 1951] */
#define GZIP 2                  /* gzip algorithm [RFC 1952] */
#define COMPRESS 3              /* Not handled, added for completeness */

#ifdef HAVE_LIBZ
  zlibInitState zlib_init;      /* possible zlib init state;
                                   undefined if Content-Encoding header. */
  z_stream z;                   /* State structure for zlib. */
#endif

  time_t timeofdoc;
  long bodywrites;

  char *buf;
  char *uploadbuf;
  curl_socket_t maxfd;

  int keepon;

  bool upload_done; /* set to TRUE when doing chunked transfer-encoding upload
                       and we're uploading the last chunk */

  bool ignorebody;  /* we read a response-body but we ignore it! */
  bool ignorecl;    /* This HTTP response has no body so we ignore the Content-
                       Length: header */

  char *location;   /* This points to an allocated version of the Location:
                       header data */
  char *newurl;     /* Set to the new URL to use when a redirect or a retry is
                       wanted */

  /* 'upload_present' is used to keep a byte counter of how much data there is
     still left in the buffer, aimed for upload. */
  ssize_t upload_present;

   /* 'upload_fromhere' is used as a read-pointer when we uploaded parts of a
      buffer, so the next read should read from where this pointer points to,
      and the 'upload_present' contains the number of bytes available at this
      position */
  char *upload_fromhere;

  bool chunk; /* if set, this is a chunked transfer-encoding */
  bool upload_chunky; /* set TRUE if we are doing chunked transfer-encoding
                         on upload */
  bool getheader;     /* TRUE if header parsing is wanted */

  bool forbidchunk;   /* used only to explicitly forbid chunk-upload for
                         specific upload buffers. See readmoredata() in
                         http.c for details. */
};

/*
 * Specific protocol handler.
 */

struct Curl_handler {
  const char * scheme;        /* URL scheme name. */

  /* Complement to setup_connection_internals(). */
  CURLcode (*setup_connection)(struct connectdata *);

  /* These two functions MUST be set to be protocol dependent */
  CURLcode (*do_it)(struct connectdata *, bool *done);
  Curl_done_func done;

  /* If the curl_do() function is better made in two halves, this
   * curl_do_more() function will be called afterwards, if set. For example
   * for doing the FTP stuff after the PASV/PORT command.
   */
  Curl_do_more_func do_more;

  /* This function *MAY* be set to a protocol-dependent function that is run
   * after the connect() and everything is done, as a step in the connection.
   * The 'done' pointer points to a bool that should be set to TRUE if the
   * function completes before return. If it doesn't complete, the caller
   * should call the curl_connecting() function until it is.
   */
  CURLcode (*connect_it)(struct connectdata *, bool *done);

  /* See above. Currently only used for FTP. */
  CURLcode (*connecting)(struct connectdata *, bool *done);
  CURLcode (*doing)(struct connectdata *, bool *done);

  /* Called from the multi interface during the PROTOCONNECT phase, and it
     should then return a proper fd set */
  int (*proto_getsock)(struct connectdata *conn,
                       curl_socket_t *socks,
                       int numsocks);

  /* Called from the multi interface during the DOING phase, and it should
     then return a proper fd set */
  int (*doing_getsock)(struct connectdata *conn,
                       curl_socket_t *socks,
                       int numsocks);

  /* Called from the multi interface during the DO_DONE, PERFORM and
     WAITPERFORM phases, and it should then return a proper fd set. Not setting
     this will make libcurl use the generic default one. */
  int (*perform_getsock)(const struct connectdata *conn,
                         curl_socket_t *socks,
                         int numsocks);

  /* This function *MAY* be set to a protocol-dependent function that is run
   * by the curl_disconnect(), as a step in the disconnection.
   */
  CURLcode (*disconnect)(struct connectdata *);

  long defport;       /* Default port. */
  long protocol;      /* PROT_* flags concerning the protocol set */
};

/* return the count of bytes sent, or -1 on error */
typedef ssize_t (Curl_send)(struct connectdata *conn, /* connection data */
                            int sockindex,            /* socketindex */
                            const void *buf,          /* data to write */
                            size_t len,               /* max amount to write */
                            CURLcode *err);           /* error to return */

/* return the count of bytes read, or -1 on error */
typedef ssize_t (Curl_recv)(struct connectdata *conn, /* connection data */
                            int sockindex,            /* socketindex */
                            char *buf,                /* store data here */
                            size_t len,               /* max amount to read */
                            CURLcode *err);           /* error to return */

/*
 * The connectdata struct contains all fields and variables that should be
 * unique for an entire connection.
 */
struct connectdata {
  /* 'data' is the CURRENT SessionHandle using this connection -- take great
     caution that this might very well vary between different times this
     connection is used! */
  struct SessionHandle *data;

  /* chunk is for HTTP chunked encoding, but is in the general connectdata
     struct only because we can do just about any protocol through a HTTP proxy
     and a HTTP proxy may in fact respond using chunked encoding */
  struct Curl_chunker chunk;

  bool inuse; /* This is a marker for the connection cache logic. If this is
                 TRUE this handle is being used by an easy handle and cannot
                 be used by any other easy handle without careful
                 consideration (== only for pipelining). */

  /**** Fields set when inited and not modified again */
  long connectindex; /* what index in the connection cache connects index this
                        particular struct has */
  long protocol; /* PROT_* flags concerning the protocol set */
#define PROT_HTTP    CURLPROTO_HTTP
#define PROT_HTTPS   CURLPROTO_HTTPS
#define PROT_FTP     CURLPROTO_FTP
#define PROT_TELNET  CURLPROTO_TELNET
#define PROT_DICT    CURLPROTO_DICT
#define PROT_LDAP    CURLPROTO_LDAP
#define PROT_FILE    CURLPROTO_FILE
#define PROT_FTPS    CURLPROTO_FTPS
#define PROT_TFTP    CURLPROTO_TFTP
#define PROT_SCP     CURLPROTO_SCP
#define PROT_SFTP    CURLPROTO_SFTP
#define PROT_IMAP    CURLPROTO_IMAP
#define PROT_IMAPS   CURLPROTO_IMAPS
#define PROT_POP3    CURLPROTO_POP3
#define PROT_POP3S   CURLPROTO_POP3S
#define PROT_SMTP    CURLPROTO_SMTP
#define PROT_SMTPS   CURLPROTO_SMTPS
#define PROT_RTSP    CURLPROTO_RTSP
#define PROT_RTMP    CURLPROTO_RTMP
#define PROT_RTMPT   CURLPROTO_RTMPT
#define PROT_RTMPE   CURLPROTO_RTMPE
#define PROT_RTMPTE  CURLPROTO_RTMPTE
#define PROT_RTMPS   CURLPROTO_RTMPS
#define PROT_RTMPTS  CURLPROTO_RTMPTS
#define PROT_GOPHER  CURLPROTO_GOPHER

/* (1<<25) is currently the highest used bit in the public bitmask. We make
   sure we use "private bits" above the public ones to make things easier;
   Gopher will not conflict with the current bit 25. */

#define PROT_EXTMASK 0x03ffffff

#define PROT_SSL     (1<<29) /* protocol requires SSL */

/* these ones need action before socket close */
#define PROT_CLOSEACTION (PROT_FTP | PROT_IMAP | PROT_POP3)
#define PROT_DUALCHANNEL PROT_FTP /* these protocols use two connections */

  /* 'dns_entry' is the particular host we use. This points to an entry in the
     DNS cache and it will not get pruned while locked. It gets unlocked in
     Curl_done(). This entry will be NULL if the connection is re-used as then
     there is no name resolve done. */
  struct Curl_dns_entry *dns_entry;

  /* 'ip_addr' is the particular IP we connected to. It points to a struct
     within the DNS cache, so this pointer is only valid as long as the DNS
     cache entry remains locked. It gets unlocked in Curl_done() */
  Curl_addrinfo *ip_addr;

  /* 'ip_addr_str' is the ip_addr data as a human readable string.
     It remains available as long as the connection does, which is longer than
     the ip_addr itself. */
  char ip_addr_str[MAX_IPADR_LEN];

  unsigned int scope;    /* address scope for IPv6 */

  int socktype;  /* SOCK_STREAM or SOCK_DGRAM */

  struct hostname host;
  struct hostname proxy;

  long port;       /* which port to use locally */
  unsigned short remote_port; /* what remote port to connect to,
                                 not the proxy port! */

  char *user;    /* user name string, allocated */
  char *passwd;  /* password string, allocated */

  char *proxyuser;    /* proxy user name string, allocated */
  char *proxypasswd;  /* proxy password string, allocated */
  curl_proxytype proxytype; /* what kind of proxy that is in use */

  int httpversion;        /* the HTTP version*10 reported by the server */
  int rtspversion;        /* the RTSP version*10 reported by the server */

  struct timeval now;     /* "current" time */
  struct timeval created; /* creation time */
  curl_socket_t sock[2]; /* two sockets, the second is used for the data
                            transfer when doing FTP */

  Curl_recv *recv[2];
  Curl_send *send[2];

  struct ssl_connect_data ssl[2]; /* this is for ssl-stuff */
  struct ssl_config_data ssl_config;

  struct ConnectBits bits;    /* various state-flags for this connection */

  const struct Curl_handler * handler;  /* Connection's protocol handler. */

  long ip_version; /* copied from the SessionHandle at creation time */

  /**** curl_get() phase fields */

  curl_socket_t sockfd;   /* socket to read from or CURL_SOCKET_BAD */
  curl_socket_t writesockfd; /* socket to write to, it may very
                                well be the same we read from.
                                CURL_SOCKET_BAD disables */

  /** Dynamicly allocated strings, may need to be freed before this **/
  /** struct is killed.                                             **/
  struct dynamically_allocated_data {
    char *proxyuserpwd; /* free later if not NULL! */
    char *uagent; /* free later if not NULL! */
    char *accept_encoding; /* free later if not NULL! */
    char *userpwd; /* free later if not NULL! */
    char *rangeline; /* free later if not NULL! */
    char *ref; /* free later if not NULL! */
    char *host; /* free later if not NULL */
    char *cookiehost; /* free later if not NULL */
    char *rtsp_transport; /* free later if not NULL */
  } allocptr;

  int sec_complete; /* if kerberos is enabled for this connection */
#if defined(HAVE_KRB4) || defined(HAVE_GSSAPI)
  enum protection_level command_prot;
  enum protection_level data_prot;
  enum protection_level request_data_prot;
  size_t buffer_size;
  struct krb4buffer in_buffer;
  void *app_data;
  const struct Curl_sec_client_mech *mech;
  struct sockaddr_in local_addr;
#endif

  /* the two following *_inuse fields are only flags, not counters in any way.
     If TRUE it means the channel is in use, and if FALSE it means the channel
     is up for grabs by one. */

  bool readchannel_inuse;  /* whether the read channel is in use by an easy
                              handle */
  bool writechannel_inuse; /* whether the write channel is in use by an easy
                              handle */
  bool server_supports_pipelining; /* TRUE if server supports pipelining,
                                      set after first response */

  struct curl_llist *send_pipe; /* List of handles waiting to
                                   send on this pipeline */
  struct curl_llist *recv_pipe; /* List of handles waiting to read
                                   their responses on this pipeline */
  struct curl_llist *pend_pipe; /* List of pending handles on
                                   this pipeline */
  struct curl_llist *done_pipe; /* Handles that are finished, but
                                   still reference this connectdata */
#define MAX_PIPELINE_LENGTH 5

  char* master_buffer; /* The master buffer allocated on-demand;
                          used for pipelining. */
  size_t read_pos; /* Current read position in the master buffer */
  size_t buf_len; /* Length of the buffer?? */


  curl_seek_callback seek_func; /* function that seeks the input */
  void *seek_client;            /* pointer to pass to the seek() above */

  /*************** Request - specific items ************/

  /* previously this was in the urldata struct */
  curl_read_callback fread_func; /* function that reads the input */
  void *fread_in;           /* pointer to pass to the fread() above */

  struct ntlmdata ntlm;     /* NTLM differs from other authentication schemes
                               because it authenticates connections, not
                               single requests! */
  struct ntlmdata proxyntlm; /* NTLM data for proxy */

  char syserr_buf [256]; /* buffer for Curl_strerror() */

#ifdef CURLRES_ASYNCH
  /* data used for the asynch name resolve callback */
  struct Curl_async async;
#endif

  /* These three are used for chunked-encoding trailer support */
  char *trailer; /* allocated buffer to store trailer in */
  int trlMax;    /* allocated buffer size */
  int trlPos;    /* index of where to store data */

  union {
    struct ftp_conn ftpc;
    struct ssh_conn sshc;
    struct tftp_state_data *tftpc;
    struct imap_conn imapc;
    struct pop3_conn pop3c;
    struct smtp_conn smtpc;
    struct rtsp_conn rtspc;
    void *generic;
  } proto;

  int cselect_bits; /* bitmask of socket events */
  int waitfor;      /* current READ/WRITE bits to wait for */

#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
  int socks5_gssapi_enctype;
#endif

  long verifypeer;
  long verifyhost;
};

/* The end of connectdata. */

/*
 * Struct to keep statistical and informational data.
 */
struct PureInfo {
  int httpcode;  /* Recent HTTP, FTP, or RTSP response code */
  int httpproxycode; /* response code from proxy when received separate */
  int httpversion; /* the http version number X.Y = X*10+Y */
  long filetime; /* If requested, this is might get set. Set to -1 if the time
                    was unretrievable. We cannot have this of type time_t,
                    since time_t is unsigned on several platforms such as
                    OpenVMS. */
  bool timecond;  /* set to TRUE if the time condition didn't match, which
                     thus made the document NOT get fetched */
  long header_size;  /* size of read header(s) in bytes */
  long request_size; /* the amount of bytes sent in the request(s) */
  long proxyauthavail; /* what proxy auth types were announced */
  long httpauthavail;  /* what host auth types were announced */
  long numconnects; /* how many new connection did libcurl created */
  char *contenttype; /* the content type of the object */
  char *wouldredirect; /* URL this would've been redirected to if asked to */
  char ip[MAX_IPADR_LEN]; /* this buffer gets the numerical ip version stored
                             at the connect *attempt* so it will get the last
                             tried connect IP even on failures */
  long port; /* the remote port the last connection was established to */
  char localip[MAX_IPADR_LEN]; /* this buffer gets the numerical (local) ip
                                  stored from where the last connection was
                                  established */
  long localport; /* the local (src) port the last connection
                     originated from */
  struct curl_certinfo certs; /* info about the certs, only populated in
                                 OpenSSL builds. Asked for with
                                 CURLOPT_CERTINFO / CURLINFO_CERTINFO */
};


struct Progress {
  long lastshow; /* time() of the last displayed progress meter or NULL to
                    force redraw at next call */
  curl_off_t size_dl; /* total expected size */
  curl_off_t size_ul; /* total expected size */
  curl_off_t downloaded; /* transfered so far */
  curl_off_t uploaded; /* transfered so far */

  curl_off_t current_speed; /* uses the currently fastest transfer */

  bool callback;  /* set when progress callback is used */
  int width; /* screen width at download start */
  int flags; /* see progress.h */

  double timespent;

  curl_off_t dlspeed;
  curl_off_t ulspeed;

  double t_nslookup;
  double t_connect;
  double t_appconnect;
  double t_pretransfer;
  double t_starttransfer;
  double t_redirect;

  struct timeval start;
  struct timeval t_startsingle;
#define CURR_TIME (5+1) /* 6 entries for 5 seconds */

  curl_off_t speeder[ CURR_TIME ];
  struct timeval speeder_time[ CURR_TIME ];
  int speeder_c;
};

typedef enum {
  HTTPREQ_NONE, /* first in list */
  HTTPREQ_GET,
  HTTPREQ_POST,
  HTTPREQ_POST_FORM, /* we make a difference internally */
  HTTPREQ_PUT,
  HTTPREQ_HEAD,
  HTTPREQ_CUSTOM,
  HTTPREQ_LAST /* last in list */
} Curl_HttpReq;

typedef enum {
    RTSPREQ_NONE, /* first in list */
    RTSPREQ_OPTIONS,
    RTSPREQ_DESCRIBE,
    RTSPREQ_ANNOUNCE,
    RTSPREQ_SETUP,
    RTSPREQ_PLAY,
    RTSPREQ_PAUSE,
    RTSPREQ_TEARDOWN,
    RTSPREQ_GET_PARAMETER,
    RTSPREQ_SET_PARAMETER,
    RTSPREQ_RECORD,
    RTSPREQ_RECEIVE,
    RTSPREQ_LAST /* last in list */
} Curl_RtspReq;

/*
 * Values that are generated, temporary or calculated internally for a
 * "session handle" must be defined within the 'struct UrlState'.  This struct
 * will be used within the SessionHandle struct. When the 'SessionHandle'
 * struct is cloned, this data MUST NOT be copied.
 *
 * Remember that any "state" information goes globally for the curl handle.
 * Session-data MUST be put in the connectdata struct and here.  */
#define MAX_CURL_USER_LENGTH 256
#define MAX_CURL_PASSWORD_LENGTH 256
#define MAX_CURL_USER_LENGTH_TXT "255"
#define MAX_CURL_PASSWORD_LENGTH_TXT "255"

struct auth {
  long want;  /* Bitmask set to the authentication methods wanted by the app
                 (with CURLOPT_HTTPAUTH or CURLOPT_PROXYAUTH). */
  long picked;
  long avail; /* bitmask for what the server reports to support for this
                 resource */
  bool done;  /* TRUE when the auth phase is done and ready to do the *actual*
                 request */
  bool multi; /* TRUE if this is not yet authenticated but within the auth
                 multipass negotiation */
  bool iestyle; /* TRUE if digest should be done IE-style or FALSE if it should
                   be RFC compliant */
};

struct conncache {
  /* 'connects' will be an allocated array with pointers. If the pointer is
     set, it holds an allocated connection. */
  struct connectdata **connects;
  long num;           /* number of entries of the 'connects' array */
  enum {
    CONNCACHE_PRIVATE, /* used for an easy handle alone */
    CONNCACHE_MULTI    /* shared within a multi handle */
  } type;
};


struct UrlState {
  enum {
    Curl_if_none,
    Curl_if_easy,
    Curl_if_multi
  } used_interface;

  struct conncache *connc; /* points to the connection cache this handle
                              uses */

  /* buffers to store authentication data in, as parsed from input options */
  struct timeval keeps_speed; /* for the progress meter really */

  long lastconnect;  /* index of most recent connect or -1 if undefined */

  char *headerbuff; /* allocated buffer to store headers in */
  size_t headersize;   /* size of the allocation */

  char buffer[BUFSIZE+1]; /* download buffer */
  char uploadbuffer[BUFSIZE+1]; /* upload buffer */
  curl_off_t current_speed;  /* the ProgressShow() funcion sets this,
                                bytes / second */
  bool this_is_a_follow; /* this is a followed Location: request */

  char *first_host; /* if set, this should be the host name that we will
                       sent authorization to, no else. Used to make Location:
                       following not keep sending user+password... This is
                       strdup() data.
                    */
  struct curl_ssl_session *session; /* array of 'numsessions' size */
  long sessionage;                  /* number of the most recent session */
  char *tempwrite;      /* allocated buffer to keep data in when a write
                           callback returns to make the connection paused */
  size_t tempwritesize; /* size of the 'tempwrite' allocated buffer */
  int tempwritetype;    /* type of the 'tempwrite' buffer as a bitmask that is
                           used with Curl_client_write() */
  char *scratch; /* huge buffer[BUFSIZE*2] when doing upload CRLF replacing */
  bool errorbuf; /* Set to TRUE if the error buffer is already filled in.
                    This must be set to FALSE every time _easy_perform() is
                    called. */
  int os_errno;  /* filled in with errno whenever an error occurs */
#ifdef HAVE_SIGNAL
  /* storage for the previous bag^H^H^HSIGPIPE signal handler :-) */
  void (*prev_signal)(int sig);
#endif
  bool allow_port; /* Is set.use_port allowed to take effect or not. This
                      is always set TRUE when curl_easy_perform() is called. */
  struct digestdata digest;      /* state data for host Digest auth */
  struct digestdata proxydigest; /* state data for proxy Digest auth */

#ifdef HAVE_GSSAPI
  struct negotiatedata negotiate; /* state data for host Negotiate auth */
  struct negotiatedata proxyneg; /* state data for proxy Negotiate auth */
#endif

  struct auth authhost;  /* auth details for host */
  struct auth authproxy; /* auth details for proxy */

  bool authproblem; /* TRUE if there's some problem authenticating */

#ifdef USE_ARES
  ares_channel areschannel; /* for name resolves */
#endif

#if defined(USE_SSLEAY) && defined(HAVE_OPENSSL_ENGINE_H)
  ENGINE *engine;
#endif /* USE_SSLEAY */
  struct timeval expiretime; /* set this with Curl_expire() only */
  struct Curl_tree timenode; /* for the splay stuff */
  struct curl_llist *timeoutlist; /* list of pending timeouts */

  /* a place to store the most recently set FTP entrypath */
  char *most_recent_ftp_entrypath;

  /* set after initial USER failure, to prevent an authentication loop */
  bool ftp_trying_alternative;

  int httpversion;       /* the lowest HTTP version*10 reported by any server
                            involved in this request */
  bool expect100header;  /* TRUE if we added Expect: 100-continue */

  bool pipe_broke; /* TRUE if the connection we were pipelined on broke
                      and we need to restart from the beginning */

#if !defined(WIN32) && !defined(MSDOS) && !defined(__EMX__) && \
    !defined(__SYMBIAN32__)
/* do FTP line-end conversions on most platforms */
#define CURL_DO_LINEEND_CONV
  /* for FTP downloads: track CRLF sequences that span blocks */
  bool prev_block_had_trailing_cr;
  /* for FTP downloads: how many CRLFs did we converted to LFs? */
  curl_off_t crlf_conversions;
#endif
  /* If set to non-NULL, there's a connection in a shared connection cache
     that uses this handle so we can't kill this SessionHandle just yet but
     must keep it around and add it to the list of handles to kill once all
     its connections are gone */
  void *shared_conn;
  bool closed; /* set to TRUE when curl_easy_cleanup() has been called on this
                  handle, but it is kept around as mentioned for
                  shared_conn */
  char *pathbuffer;/* allocated buffer to store the URL's path part in */
  char *path;      /* path to use, points to somewhere within the pathbuffer
                      area */
  bool slash_removed; /* set TRUE if the 'path' points to a path where the
                         initial URL slash separator has been taken off */
  bool use_range;
  bool rangestringalloc; /* the range string is malloc()'ed */

  char *range; /* range, if used. See README for detailed specification on
                  this syntax. */
  curl_off_t resume_from; /* continue [ftp] transfer from here */

  /* This RTSP state information survives requests and connections */
  long rtsp_next_client_CSeq; /* the session's next client CSeq */
  long rtsp_next_server_CSeq; /* the session's next server CSeq */
  long rtsp_CSeq_recv; /* most recent CSeq received */

  /* Protocol specific data.
   *
   *************************************************************************
   * Note that this data will be REMOVED after each request, so anything that
   * should be kept/stored on a per-connection basis and thus live for the
   * next request on the same connection MUST be put in the connectdata struct!
   *************************************************************************/
  union {
    struct HTTP *http;
    struct HTTP *https;  /* alias, just for the sake of being more readable */
    struct RTSP *rtsp;
    struct FTP *ftp;
    /* void *tftp;    not used */
    struct FILEPROTO *file;
    void *telnet;        /* private for telnet.c-eyes only */
    void *generic;
    struct SSHPROTO *ssh;
    struct FTP *imap;
    struct FTP *pop3;
    struct FTP *smtp;
  } proto;
  /* current user of this SessionHandle instance, or NULL */
  struct connectdata *current_conn;

  /* if true, force SSL connection retry (workaround for certain servers) */
  bool ssl_connect_retry;
};


/*
 * This 'DynamicStatic' struct defines dynamic states that actually change
 * values in the 'UserDefined' area, which MUST be taken into consideration
 * if the UserDefined struct is cloned or similar. You can probably just
 * copy these, but each one indicate a special action on other data.
 */

struct DynamicStatic {
  char *url;        /* work URL, copied from UserDefined */
  bool url_alloc;   /* URL string is malloc()'ed */
  char *referer;    /* referer string */
  bool referer_alloc; /* referer sting is malloc()ed */
  struct curl_slist *cookielist; /* list of cookie files set by
                                    curl_easy_setopt(COOKIEFILE) calls */
  struct curl_slist *resolve; /* set to point to the set.resolve list when
                                 this should be dealt with in pretransfer */
};

/*
 * This 'UserDefined' struct must only contain data that is set once to go
 * for many (perhaps) independent connections. Values that are generated or
 * calculated internally for the "session handle" MUST be defined within the
 * 'struct UrlState' instead. The only exceptions MUST note the changes in
 * the 'DynamicStatic' struct.
 * Character pointer fields point to dynamic storage, unless otherwise stated.
 */
struct Curl_one_easy; /* declared and used only in multi.c */
struct Curl_multi;    /* declared and used only in multi.c */

enum dupstring {
  STRING_CERT,            /* client certificate file name */
  STRING_CERT_TYPE,       /* format for certificate (default: PEM)*/
  STRING_COOKIE,          /* HTTP cookie string to send */
  STRING_COOKIEJAR,       /* dump all cookies to this file */
  STRING_CUSTOMREQUEST,   /* HTTP/FTP/RTSP request/method to use */
  STRING_DEVICE,          /* local network interface/address to use */
  STRING_ENCODING,        /* Accept-Encoding string */
  STRING_FTP_ACCOUNT,     /* ftp account data */
  STRING_FTP_ALTERNATIVE_TO_USER, /* command to send if USER/PASS fails */
  STRING_FTPPORT,         /* port to send with the FTP PORT command */
  STRING_KEY,             /* private key file name */
  STRING_KEY_PASSWD,      /* plain text private key password */
  STRING_KEY_TYPE,        /* format for private key (default: PEM) */
  STRING_KRB_LEVEL,       /* krb security level */
  STRING_NETRC_FILE,      /* if not NULL, use this instead of trying to find
                             $HOME/.netrc */
  STRING_COPYPOSTFIELDS,  /* if POST, set the fields' values here */
  STRING_PROXY,           /* proxy to use */
  STRING_SET_RANGE,       /* range, if used */
  STRING_SET_REFERER,     /* custom string for the HTTP referer field */
  STRING_SET_URL,         /* what original URL to work on */
  STRING_SSL_CAPATH,      /* CA directory name (doesn't work on windows) */
  STRING_SSL_CAFILE,      /* certificate file to verify peer against */
  STRING_SSL_CIPHER_LIST, /* list of ciphers to use */
  STRING_SSL_EGDSOCKET,   /* path to file containing the EGD daemon socket */
  STRING_SSL_RANDOM_FILE, /* path to file containing "random" data */
  STRING_USERAGENT,       /* User-Agent string */
  STRING_SSL_CRLFILE,     /* crl file to check certificate */
  STRING_SSL_ISSUERCERT,  /* issuer cert file to check certificate */
  STRING_USERNAME,        /* <username>, if used */
  STRING_PASSWORD,        /* <password>, if used */
  STRING_PROXYUSERNAME,   /* Proxy <username>, if used */
  STRING_PROXYPASSWORD,   /* Proxy <password>, if used */
  STRING_NOPROXY,         /* List of hosts which should not use the proxy, if
                             used */
  STRING_RTSP_SESSION_ID, /* Session ID to use */
  STRING_RTSP_STREAM_URI, /* Stream URI for this request */
  STRING_RTSP_TRANSPORT,  /* Transport for this session */
#ifdef USE_LIBSSH2
  STRING_SSH_PRIVATE_KEY, /* path to the private key file for auth */
  STRING_SSH_PUBLIC_KEY,  /* path to the public key file for auth */
  STRING_SSH_HOST_PUBLIC_KEY_MD5, /* md5 of host public key in ascii hex */
  STRING_SSH_KNOWNHOSTS,  /* file name of knownhosts file */
#endif
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
  STRING_SOCKS5_GSSAPI_SERVICE,  /* GSSAPI service name */
#endif
  STRING_MAIL_FROM,

  /* -- end of strings -- */
  STRING_LAST /* not used, just an end-of-list marker */
};

struct UserDefined {
  FILE *err;         /* the stderr user data goes here */
  void *debugdata;   /* the data that will be passed to fdebug */
  char *errorbuffer; /* (Static) store failure messages in here */
  long proxyport; /* If non-zero, use this port number by default. If the
                     proxy string features a ":[port]" that one will override
                     this. */
  void *out;         /* the fetched file goes here */
  void *in;          /* the uploaded file is read from here */
  void *writeheader; /* write the header to this if non-NULL */
  void *rtp_out;     /* write RTP to this if non-NULL */
  long use_port;     /* which port to use (when not using default) */
  long httpauth;     /* what kind of HTTP authentication to use (bitmask) */
  long proxyauth;    /* what kind of proxy authentication to use (bitmask) */
  long followlocation; /* as in HTTP Location: */
  long maxredirs;    /* maximum no. of http(s) redirects to follow, set to -1
                        for infinity */
  bool post301;      /* Obey RFC 2616/10.3.2 and keep POSTs as POSTs after a
                        301 */
  bool post302;      /* keep POSTs as POSTs after a 302 */
  bool free_referer; /* set TRUE if 'referer' points to a string we
                        allocated */
  void *postfields;  /* if POST, set the fields' values here */
  curl_seek_callback seek_func;      /* function that seeks the input */
  curl_off_t postfieldsize; /* if POST, this might have a size to use instead
                               of strlen(), and then the data *may* be binary
                               (contain zero bytes) */
  unsigned short localport; /* local port number to bind to */
  int localportrange; /* number of additional port numbers to test in case the
                         'localport' one can't be bind()ed */
  curl_write_callback fwrite_func;   /* function that stores the output */
  curl_write_callback fwrite_header; /* function that stores headers */
  curl_write_callback fwrite_rtp;    /* function that stores interleaved RTP */
  curl_read_callback fread_func;     /* function that reads the input */
  int is_fread_set; /* boolean, has read callback been set to non-NULL? */
  int is_fwrite_set; /* boolean, has write callback been set to non-NULL? */
  curl_progress_callback fprogress;  /* function for progress information */
  curl_debug_callback fdebug;      /* function that write informational data */
  curl_ioctl_callback ioctl_func;  /* function for I/O control */
  curl_sockopt_callback fsockopt;  /* function for setting socket options */
  void *sockopt_client; /* pointer to pass to the socket options callback */
  curl_opensocket_callback fopensocket; /* function for checking/translating
                                           the address and opening the socket */
  void* opensocket_client;

  void *seek_client;    /* pointer to pass to the seek callback */
  /* the 3 curl_conv_callback functions below are used on non-ASCII hosts */
  /* function to convert from the network encoding: */
  curl_conv_callback convfromnetwork;
  /* function to convert to the network encoding: */
  curl_conv_callback convtonetwork;
  /* function to convert from UTF-8 encoding: */
  curl_conv_callback convfromutf8;

  void *progress_client; /* pointer to pass to the progress callback */
  void *ioctl_client;   /* pointer to pass to the ioctl callback */
  long timeout;         /* in milliseconds, 0 means no timeout */
  long connecttimeout;  /* in milliseconds, 0 means no timeout */
  long server_response_timeout; /* in milliseconds, 0 means no timeout */
  long tftp_blksize ; /* in bytes, 0 means use default */
  curl_off_t infilesize;      /* size of file to upload, -1 means unknown */
  long low_speed_limit; /* bytes/second */
  long low_speed_time;  /* number of seconds */
  curl_off_t max_send_speed; /* high speed limit in bytes/second for upload */
  curl_off_t max_recv_speed; /* high speed limit in bytes/second for download */
  curl_off_t set_resume_from;  /* continue [ftp] transfer from here */
  struct curl_slist *headers; /* linked list of extra headers */
  struct curl_httppost *httppost;  /* linked list of POST data */
  bool cookiesession;   /* new cookie session? */
  bool crlf;            /* convert crlf on ftp upload(?) */
  struct curl_slist *quote;     /* after connection is established */
  struct curl_slist *postquote; /* after the transfer */
  struct curl_slist *prequote; /* before the transfer, after type */
  struct curl_slist *source_quote;  /* 3rd party quote */
  struct curl_slist *source_prequote;  /* in 3rd party transfer mode - before
                                          the transfer on source host */
  struct curl_slist *source_postquote; /* in 3rd party transfer mode - after
                                          the transfer on source host */
  struct curl_slist *telnet_options; /* linked list of telnet options */
  struct curl_slist *resolve;     /* list of names to add/remove from
                                     DNS cache */
  curl_TimeCond timecondition; /* kind of time/date comparison */
  time_t timevalue;       /* what time to compare with */
  Curl_HttpReq httpreq;   /* what kind of HTTP request (if any) is this */
  long httpversion; /* when non-zero, a specific HTTP version requested to
                       be used in the library's request(s) */
  struct ssl_config_data ssl;  /* user defined SSL stuff */
  curl_proxytype proxytype; /* what kind of proxy that is in use */
  long dns_cache_timeout; /* DNS cache timeout */
  long buffer_size;      /* size of receive buffer to use */
  void *private_data; /* application-private data */

  struct Curl_one_easy *one_easy; /* When adding an easy handle to a multi
                                     handle, an internal 'Curl_one_easy'
                                     struct is created and this is a pointer
                                     to the particular struct associated with
                                     this SessionHandle */

  struct curl_slist *http200aliases; /* linked list of aliases for http200 */

  long ipver; /* the CURL_IPRESOLVE_* defines in the public header file
                 0 - whatever, 1 - v2, 2 - v6 */

  curl_off_t max_filesize; /* Maximum file size to download */

  curl_ftpfile ftp_filemethod; /* how to get to a file when FTP is used  */

  int ftp_create_missing_dirs; /* 1 - create directories that don't exist
                                  2 - the same but also allow MKD to fail once
                               */

  curl_sshkeycallback ssh_keyfunc; /* key matching callback */
  void *ssh_keyfunc_userp;         /* custom pointer to callback */

/* Here follows boolean settings that define how to behave during
   this session. They are STATIC, set by libcurl users or at least initially
   and they don't change during operations. */

  bool printhost;        /* printing host name in debug info */
  bool get_filetime;     /* get the time and get of the remote file */
  bool tunnel_thru_httpproxy; /* use CONNECT through a HTTP proxy */
  bool prefer_ascii;     /* ASCII rather than binary */
  bool ftp_append;       /* append, not overwrite, on upload */
  bool ftp_list_only;    /* switch FTP command for listing directories */
  bool ftp_use_port;     /* use the FTP PORT command */
  bool hide_progress;    /* don't use the progress meter */
  bool http_fail_on_error;  /* fail on HTTP error codes >= 300 */
  bool http_follow_location; /* follow HTTP redirects */
  bool http_disable_hostname_check_before_authentication;
  bool include_header;   /* include received protocol headers in data output */
  bool http_set_referer; /* is a custom referer used */
  bool http_auto_referer; /* set "correct" referer when following location: */
  bool opt_no_body;      /* as set with CURLOPT_NO_BODY */
  bool set_port;         /* custom port number used */
  bool upload;           /* upload request */
  enum CURL_NETRC_OPTION
       use_netrc;        /* defined in include/curl.h */
  bool verbose;          /* output verbosity */
  bool krb;              /* kerberos connection requested */
  bool reuse_forbid;     /* forbidden to be reused, close after use */
  bool reuse_fresh;      /* do not re-use an existing connection  */
  bool ftp_use_epsv;     /* if EPSV is to be attempted or not */
  bool ftp_use_eprt;     /* if EPRT is to be attempted or not */
  bool ftp_use_pret;     /* if PRET is to be used before PASV or not */

  curl_usessl ftp_ssl;   /* if AUTH TLS is to be attempted etc, for FTP or
                            IMAP or POP3 or others! */
  curl_ftpauth ftpsslauth; /* what AUTH XXX to be attempted */
  curl_ftpccc ftp_ccc;   /* FTP CCC options */
  bool no_signal;        /* do not use any signal/alarm handler */
  bool global_dns_cache; /* subject for future removal */
  bool tcp_nodelay;      /* whether to enable TCP_NODELAY or not */
  bool ignorecl;         /* ignore content length */
  bool ftp_skip_ip;      /* skip the IP address the FTP server passes on to
                            us */
  bool connect_only;     /* make connection, let application use the socket */
  long ssh_auth_types;   /* allowed SSH auth types */
  bool http_te_skip;     /* pass the raw body data to the user, even when
                            transfer-encoded (chunked, compressed) */
  bool http_ce_skip;     /* pass the raw body data to the user, even when
                            content-encoded (chunked, compressed) */
  long new_file_perms;    /* Permissions to use when creating remote files */
  long new_directory_perms; /* Permissions to use when creating remote dirs */
  bool proxy_transfer_mode; /* set transfer mode (;type=<a|i>) when doing FTP
                               via an HTTP proxy */
  char *str[STRING_LAST]; /* array of strings, pointing to allocated memory */
  unsigned int scope;    /* address scope for IPv6 */
  long allowed_protocols;
  long redir_protocols;
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
  long socks5_gssapi_nec; /* flag to support nec socks5 server */
#endif
  struct curl_slist *mail_rcpt; /* linked list of mail recipients */
  /* Common RTSP header options */
  Curl_RtspReq rtspreq; /* RTSP request type */
  long rtspversion; /* like httpversion, for RTSP */
  bool wildcardmatch; /* enable wildcard matching */
  curl_chunk_bgn_callback chunk_bgn; /* called before part of transfer starts */
  curl_chunk_end_callback chunk_end; /* called after part transferring
                                        stopped */
  curl_fnmatch_callback fnmatch; /* callback to decide which file corresponds
                                    to pattern (e.g. if WILDCARDMATCH is on) */
  void *fnmatch_data;
};

struct Names {
  struct curl_hash *hostcache;
  enum {
    HCACHE_NONE,    /* not pointing to anything */
    HCACHE_PRIVATE, /* points to our own */
    HCACHE_GLOBAL,  /* points to the (shrug) global one */
    HCACHE_MULTI,   /* points to a shared one in the multi handle */
    HCACHE_SHARED   /* points to a shared one in a shared object */
  } hostcachetype;
};

/*
 * The 'connectdata' struct MUST have all the connection oriented stuff as we
 * may have several simultaneous connections and connection structs in memory.
 *
 * The 'struct UserDefined' must only contain data that is set once to go for
 * many (perhaps) independent connections. Values that are generated or
 * calculated internally for the "session handle" must be defined within the
 * 'struct UrlState' instead.
 */

struct SessionHandle {
  struct Names dns;
  struct Curl_multi *multi;    /* if non-NULL, points to the multi handle
                                  struct to which this "belongs" */
  struct Curl_one_easy *multi_pos; /* if non-NULL, points to its position
                                      in multi controlling structure to assist
                                      in removal. */
  struct Curl_share *share;    /* Share, handles global variable mutexing */
  struct SingleRequest req;    /* Request-specific data */
  struct UserDefined set;      /* values set by the libcurl user */
  struct DynamicStatic change; /* possibly modified userdefined data */
  struct CookieInfo *cookies;  /* the cookies, read from files and servers.
                                  NOTE that the 'cookie' field in the
                                  UserDefined struct defines if the "engine"
                                  is to be used or not. */
  struct Progress progress;    /* for all the progress meter data */
  struct UrlState state;       /* struct for fields used for state info and
                                  other dynamic purposes */
  struct WildcardData wildcard; /* wildcard download state info */
  struct PureInfo info;        /* stats, reports and info data */
#if defined(CURL_DOES_CONVERSIONS) && defined(HAVE_ICONV)
  iconv_t outbound_cd;         /* for translating to the network encoding */
  iconv_t inbound_cd;          /* for translating from the network encoding */
  iconv_t utf8_cd;             /* for translating to UTF8 */
#endif /* CURL_DOES_CONVERSIONS && HAVE_ICONV */
  unsigned int magic;          /* set to a CURLEASY_MAGIC_NUMBER */
};

#define LIBCURL_NAME "libcurl"

#endif