url.c

     */
    result = Curl_ssl_set_engine_default(data);
    break;
  case CURLOPT_CRLF:
    /*
     * Kludgy option to enable CRLF conversions. Subject for removal.
     */
    data->set.crlf = (bool)(0 != va_arg(param, long));
    break;

  case CURLOPT_INTERFACE:
    /*
     * Set what interface or address/hostname to bind the socket to when
     * performing an operation and thus what from-IP your connection will use.
     */
    result = setstropt(&data->set.str[STRING_DEVICE],
                       va_arg(param, char *));
    break;
  case CURLOPT_LOCALPORT:
    /*
     * Set what local port to bind the socket to when performing an operation.
     */
    data->set.localport = curlx_sltous(va_arg(param, long));
    break;
  case CURLOPT_LOCALPORTRANGE:
    /*
     * Set number of local ports to try, starting with CURLOPT_LOCALPORT.
     */
    data->set.localportrange = curlx_sltosi(va_arg(param, long));
    break;
  case CURLOPT_KRBLEVEL:
    /*
     * A string that defines the kerberos security level.
     */
    result = setstropt(&data->set.str[STRING_KRB_LEVEL],
                       va_arg(param, char *));
    data->set.krb = (bool)(NULL != data->set.str[STRING_KRB_LEVEL]);
    break;
  case CURLOPT_SSL_VERIFYPEER:
    /*
     * Enable peer SSL verifying.
     */
    data->set.ssl.verifypeer = va_arg(param, long);
    break;
  case CURLOPT_SSL_VERIFYHOST:
    /*
     * Enable verification of the CN contained in the peer certificate
     */
    data->set.ssl.verifyhost = va_arg(param, long);
    break;
#ifdef USE_SSLEAY
    /* since these two options are only possible to use on an OpenSSL-
       powered libcurl we #ifdef them on this condition so that libcurls
       built against other SSL libs will return a proper error when trying
       to set this option! */
  case CURLOPT_SSL_CTX_FUNCTION:
    /*
     * Set a SSL_CTX callback
     */
    data->set.ssl.fsslctx = va_arg(param, curl_ssl_ctx_callback);
    break;
  case CURLOPT_SSL_CTX_DATA:
    /*
     * Set a SSL_CTX callback parameter pointer
     */
    data->set.ssl.fsslctxp = va_arg(param, void *);
    break;
  case CURLOPT_CERTINFO:
    data->set.ssl.certinfo = (bool)(0 != va_arg(param, long));
    break;
#endif
  case CURLOPT_CAINFO:
    /*
     * Set CA info for SSL connection. Specify file name of the CA certificate
     */
    result = setstropt(&data->set.str[STRING_SSL_CAFILE],
                       va_arg(param, char *));
    break;
  case CURLOPT_CAPATH:
    /*
     * Set CA path info for SSL connection. Specify directory name of the CA
     * certificates which have been prepared using openssl c_rehash utility.
     */
    /* This does not work on windows. */
    result = setstropt(&data->set.str[STRING_SSL_CAPATH],
                       va_arg(param, char *));
    break;
  case CURLOPT_CRLFILE:
    /*
     * Set CRL file info for SSL connection. Specify file name of the CRL
     * to check certificates revocation
     */
    result = setstropt(&data->set.str[STRING_SSL_CRLFILE],
                       va_arg(param, char *));
    break;
  case CURLOPT_ISSUERCERT:
    /*
     * Set Issuer certificate file
     * to check certificates issuer
     */
    result = setstropt(&data->set.str[STRING_SSL_ISSUERCERT],
                       va_arg(param, char *));
    break;
  case CURLOPT_TELNETOPTIONS:
    /*
     * Set a linked list of telnet options
     */
    data->set.telnet_options = va_arg(param, struct curl_slist *);
    break;

  case CURLOPT_BUFFERSIZE:
    /*
     * The application kindly asks for a differently sized receive buffer.
     * If it seems reasonable, we'll use it.
     */
    data->set.buffer_size = va_arg(param, long);

    if((data->set.buffer_size> (BUFSIZE -1 )) ||
       (data->set.buffer_size < 1))
      data->set.buffer_size = 0; /* huge internal default */

    break;

  case CURLOPT_NOSIGNAL:
    /*
     * The application asks not to set any signal() or alarm() handlers,
     * even when using a timeout.
     */
    data->set.no_signal = (bool)(0 != va_arg(param, long));
    break;

  case CURLOPT_SHARE:
  {
    struct Curl_share *set;
    set = va_arg(param, struct Curl_share *);

    /* disconnect from old share, if any */
    if(data->share) {
      Curl_share_lock(data, CURL_LOCK_DATA_SHARE, CURL_LOCK_ACCESS_SINGLE);

      if(data->dns.hostcachetype == HCACHE_SHARED) {
        data->dns.hostcache = NULL;
        data->dns.hostcachetype = HCACHE_NONE;
      }

      if(data->share->cookies == data->cookies)
        data->cookies = NULL;

      data->share->dirty--;

      Curl_share_unlock(data, CURL_LOCK_DATA_SHARE);
      data->share = NULL;
    }

    /* use new share if it set */
    data->share = set;
    if(data->share) {

      Curl_share_lock(data, CURL_LOCK_DATA_SHARE, CURL_LOCK_ACCESS_SINGLE);

      data->share->dirty++;

      if(data->share->hostcache) {
        /* use shared host cache, first free the private one if any */
        if(data->dns.hostcachetype == HCACHE_PRIVATE)
          Curl_hash_destroy(data->dns.hostcache);

        data->dns.hostcache = data->share->hostcache;
        data->dns.hostcachetype = HCACHE_SHARED;
      }
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
      if(data->share->cookies) {
        /* use shared cookie list, first free own one if any */
        if(data->cookies)
          Curl_cookie_cleanup(data->cookies);
        /* enable cookies since we now use a share that uses cookies! */
        data->cookies = data->share->cookies;
      }
#endif   /* CURL_DISABLE_HTTP */
      Curl_share_unlock(data, CURL_LOCK_DATA_SHARE);

    }
    /* check for host cache not needed,
     * it will be done by curl_easy_perform */
  }
  break;

  case CURLOPT_PRIVATE:
    /*
     * Set private data pointer.
     */
    data->set.private_data = va_arg(param, void *);
    break;

  case CURLOPT_MAXFILESIZE:
    /*
     * Set the maximum size of a file to download.
     */
    data->set.max_filesize = va_arg(param, long);
    break;

#ifdef USE_SSL
  case CURLOPT_USE_SSL:
    /*
     * Make transfers attempt to use SSL/TLS.
     */
    data->set.ftp_ssl = (curl_usessl)va_arg(param, long);
    break;
#endif
  case CURLOPT_FTPSSLAUTH:
    /*
     * Set a specific auth for FTP-SSL transfers.
     */
    data->set.ftpsslauth = (curl_ftpauth)va_arg(param, long);
    break;

  case CURLOPT_IPRESOLVE:
    data->set.ipver = va_arg(param, long);
    break;

  case CURLOPT_MAXFILESIZE_LARGE:
    /*
     * Set the maximum size of a file to download.
     */
    data->set.max_filesize = va_arg(param, curl_off_t);
    break;

  case CURLOPT_TCP_NODELAY:
    /*
     * Enable or disable TCP_NODELAY, which will disable/enable the Nagle
     * algorithm
     */
    data->set.tcp_nodelay = (bool)(0 != va_arg(param, long));
    break;

  case CURLOPT_FTP_ACCOUNT:
    result = setstropt(&data->set.str[STRING_FTP_ACCOUNT],
                       va_arg(param, char *));
    break;

  case CURLOPT_IGNORE_CONTENT_LENGTH:
    data->set.ignorecl = (bool)(0 != va_arg(param, long));
    break;

  case CURLOPT_CONNECT_ONLY:
    /*
     * No data transfer, set up connection and let application use the socket
     */
    data->set.connect_only = (bool)(0 != va_arg(param, long));
    break;

  case CURLOPT_FTP_ALTERNATIVE_TO_USER:
    result = setstropt(&data->set.str[STRING_FTP_ALTERNATIVE_TO_USER],
                       va_arg(param, char *));
    break;

  case CURLOPT_SOCKOPTFUNCTION:
    /*
     * socket callback function: called after socket() but before connect()
     */
    data->set.fsockopt = va_arg(param, curl_sockopt_callback);
    break;

  case CURLOPT_SOCKOPTDATA:
    /*
     * socket callback data pointer. Might be NULL.
     */
    data->set.sockopt_client = va_arg(param, void *);
    break;

  case CURLOPT_OPENSOCKETFUNCTION:
    /*
     * open/create socket callback function: called instead of socket(),
     * before connect()
     */
    data->set.fopensocket = va_arg(param, curl_opensocket_callback);
    break;

  case CURLOPT_OPENSOCKETDATA:
    /*
     * socket callback data pointer. Might be NULL.
     */
    data->set.opensocket_client = va_arg(param, void *);
    break;

  case CURLOPT_SSL_SESSIONID_CACHE:
    data->set.ssl.sessionid = (bool)(0 != va_arg(param, long));
    break;

#ifdef USE_LIBSSH2
    /* we only include SSH options if explicitly built to support SSH */
  case CURLOPT_SSH_AUTH_TYPES:
    data->set.ssh_auth_types = va_arg(param, long);
    break;

  case CURLOPT_SSH_PUBLIC_KEYFILE:
    /*
     * Use this file instead of the $HOME/.ssh/id_dsa.pub file
     */
    result = setstropt(&data->set.str[STRING_SSH_PUBLIC_KEY],
                       va_arg(param, char *));
    break;

  case CURLOPT_SSH_PRIVATE_KEYFILE:
    /*
     * Use this file instead of the $HOME/.ssh/id_dsa file
     */
    result = setstropt(&data->set.str[STRING_SSH_PRIVATE_KEY],
                       va_arg(param, char *));
    break;
  case CURLOPT_SSH_HOST_PUBLIC_KEY_MD5:
    /*
     * Option to allow for the MD5 of the host public key to be checked
     * for validation purposes.
     */
    result = setstropt(&data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5],
                       va_arg(param, char *));
    break;
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
  case CURLOPT_SSH_KNOWNHOSTS:
    /*
     * Store the file name to read known hosts from.
     */
    result = setstropt(&data->set.str[STRING_SSH_KNOWNHOSTS],
                       va_arg(param, char *));
    break;

  case CURLOPT_SSH_KEYFUNCTION:
    /* setting to NULL is fine since the ssh.c functions themselves will
       then rever to use the internal default */
    data->set.ssh_keyfunc = va_arg(param, curl_sshkeycallback);
    break;

  case CURLOPT_SSH_KEYDATA:
    /*
     * Custom client data to pass to the SSH keyfunc callback
     */
    data->set.ssh_keyfunc_userp = va_arg(param, void *);
    break;
#endif /* HAVE_LIBSSH2_KNOWNHOST_API */

#endif /* USE_LIBSSH2 */

  case CURLOPT_HTTP_TRANSFER_DECODING:
    /*
     * disable libcurl transfer encoding is used
     */
    data->set.http_te_skip = (bool)(0 == va_arg(param, long));
    break;

  case CURLOPT_HTTP_CONTENT_DECODING:
    /*
     * raw data passed to the application when content encoding is used
     */
    data->set.http_ce_skip = (bool)(0 == va_arg(param, long));
    break;

  case CURLOPT_NEW_FILE_PERMS:
    /*
     * Uses these permissions instead of 0644
     */
    data->set.new_file_perms = va_arg(param, long);
    break;

  case CURLOPT_NEW_DIRECTORY_PERMS:
    /*
     * Uses these permissions instead of 0755
     */
    data->set.new_directory_perms = va_arg(param, long);
    break;

  case CURLOPT_ADDRESS_SCOPE:
    /*
     * We always get longs when passed plain numericals, but for this value we
     * know that an unsigned int will always hold the value so we blindly
     * typecast to this type
     */
    data->set.scope = curlx_sltoui(va_arg(param, long));
    break;

  case CURLOPT_PROTOCOLS:
    /* set the bitmask for the protocols that are allowed to be used for the
       transfer, which thus helps the app which takes URLs from users or other
       external inputs and want to restrict what protocol(s) to deal
       with. Defaults to CURLPROTO_ALL. */
    data->set.allowed_protocols = va_arg(param, long);
    break;

  case CURLOPT_REDIR_PROTOCOLS:
    /* set the bitmask for the protocols that libcurl is allowed to follow to,
       as a subset of the CURLOPT_PROTOCOLS ones. That means the protocol needs
       to be set in both bitmasks to be allowed to get redirected to. Defaults
       to all protocols except FILE and SCP. */
    data->set.redir_protocols = va_arg(param, long);
    break;

  case CURLOPT_MAIL_FROM:
    result = setstropt(&data->set.str[STRING_MAIL_FROM],
                       va_arg(param, char *));
    break;

  case CURLOPT_MAIL_RCPT:
    /* get a list of mail recipients */
    data->set.mail_rcpt = va_arg(param, struct curl_slist *);
    break;

  case CURLOPT_RTSP_REQUEST:
    {
      /*
       * Set the RTSP request method (OPTIONS, SETUP, PLAY, etc...)
       * Would this be better if the RTSPREQ_* were just moved into here?
       */
      long curl_rtspreq = va_arg(param, long);
      Curl_RtspReq rtspreq = RTSPREQ_NONE;
      switch(curl_rtspreq) {
        case CURL_RTSPREQ_OPTIONS:
          rtspreq = RTSPREQ_OPTIONS;
          break;

        case CURL_RTSPREQ_DESCRIBE:
          rtspreq = RTSPREQ_DESCRIBE;
          break;

        case CURL_RTSPREQ_ANNOUNCE:
          rtspreq = RTSPREQ_ANNOUNCE;
          break;

        case CURL_RTSPREQ_SETUP:
          rtspreq = RTSPREQ_SETUP;
          break;

        case CURL_RTSPREQ_PLAY:
          rtspreq = RTSPREQ_PLAY;
          break;

        case CURL_RTSPREQ_PAUSE:
          rtspreq = RTSPREQ_PAUSE;
          break;

        case CURL_RTSPREQ_TEARDOWN:
          rtspreq = RTSPREQ_TEARDOWN;
          break;

        case CURL_RTSPREQ_GET_PARAMETER:
          rtspreq = RTSPREQ_GET_PARAMETER;
          break;

        case CURL_RTSPREQ_SET_PARAMETER:
          rtspreq = RTSPREQ_SET_PARAMETER;
          break;

        case CURL_RTSPREQ_RECORD:
          rtspreq = RTSPREQ_RECORD;
          break;

        case CURL_RTSPREQ_RECEIVE:
          rtspreq = RTSPREQ_RECEIVE;
          break;
        default:
          rtspreq = RTSPREQ_NONE;
      }

      data->set.rtspreq = rtspreq;
    break;
    }


  case CURLOPT_RTSP_SESSION_ID:
    /*
     * Set the RTSP Session ID manually. Useful if the application is
     * resuming a previously established RTSP session
     */
    result = setstropt(&data->set.str[STRING_RTSP_SESSION_ID],
                       va_arg(param, char *));
    break;

  case CURLOPT_RTSP_STREAM_URI:
    /*
     * Set the Stream URI for the RTSP request. Unless the request is
     * for generic server options, the application will need to set this.
     */
    result = setstropt(&data->set.str[STRING_RTSP_STREAM_URI],
                       va_arg(param, char *));
    break;

  case CURLOPT_RTSP_TRANSPORT:
    /*
     * The content of the Transport: header for the RTSP request
     */
    result = setstropt(&data->set.str[STRING_RTSP_TRANSPORT],
                       va_arg(param, char *));
    break;

  case CURLOPT_RTSP_CLIENT_CSEQ:
    /*
     * Set the CSEQ number to issue for the next RTSP request. Useful if the
     * application is resuming a previously broken connection. The CSEQ
     * will increment from this new number henceforth.
     */
    data->state.rtsp_next_client_CSeq = va_arg(param, long);
    break;

  case CURLOPT_RTSP_SERVER_CSEQ:
    /* Same as the above, but for server-initiated requests */
    data->state.rtsp_next_client_CSeq = va_arg(param, long);
    break;

  case CURLOPT_INTERLEAVEDATA:
    data->set.rtp_out = va_arg(param, void *);
    break;
  case CURLOPT_INTERLEAVEFUNCTION:
    /* Set the user defined RTP write function */
    data->set.fwrite_rtp = va_arg(param, curl_write_callback);
    break;

  case CURLOPT_WILDCARDMATCH:
    data->set.wildcardmatch = (bool)(0 != va_arg(param, long));
    break;
  case CURLOPT_CHUNK_BGN_FUNCTION:
    data->set.chunk_bgn = va_arg(param, curl_chunk_bgn_callback);
    break;
  case CURLOPT_CHUNK_END_FUNCTION:
    data->set.chunk_end = va_arg(param, curl_chunk_end_callback);
    break;
  case CURLOPT_FNMATCH_FUNCTION:
    data->set.fnmatch = va_arg(param, curl_fnmatch_callback);
    break;
  case CURLOPT_CHUNK_DATA:
    data->wildcard.customptr = va_arg(param, void *);
    break;
  case CURLOPT_FNMATCH_DATA:
    data->set.fnmatch_data = va_arg(param, void *);
    break;
#ifdef USE_TLS_SRP
  case CURLOPT_TLSAUTH_USERNAME:
    result = setstropt(&data->set.str[STRING_TLSAUTH_USERNAME],
                       va_arg(param, char *));
    if (data->set.str[STRING_TLSAUTH_USERNAME] && !data->set.ssl.authtype)
      data->set.ssl.authtype = CURL_TLSAUTH_SRP; /* default to SRP */
    break;
  case CURLOPT_TLSAUTH_PASSWORD:
    result = setstropt(&data->set.str[STRING_TLSAUTH_PASSWORD],
                       va_arg(param, char *));
    if (data->set.str[STRING_TLSAUTH_USERNAME] && !data->set.ssl.authtype)
      data->set.ssl.authtype = CURL_TLSAUTH_SRP; /* default to SRP */
    break;
  case CURLOPT_TLSAUTH_TYPE:
    if (strncmp((char *)va_arg(param, char *), "SRP", strlen("SRP")) == 0)
      data->set.ssl.authtype = CURL_TLSAUTH_SRP;
    else
      data->set.ssl.authtype = CURL_TLSAUTH_NONE;
    break;
#endif
  default:
    /* unknown tag and its companion, just ignore: */
    result = CURLE_FAILED_INIT; /* correct this */
    break;
  }

  return result;
}

static void conn_free(struct connectdata *conn)
{
  if(!conn)
    return;

  /* close the SSL stuff before we close any sockets since they will/may
     write to the sockets */
  Curl_ssl_close(conn, FIRSTSOCKET);
  Curl_ssl_close(conn, SECONDARYSOCKET);

  /* close possibly still open sockets */
  if(CURL_SOCKET_BAD != conn->sock[SECONDARYSOCKET])
    sclose(conn->sock[SECONDARYSOCKET]);
  if(CURL_SOCKET_BAD != conn->sock[FIRSTSOCKET])
    sclose(conn->sock[FIRSTSOCKET]);

  Curl_safefree(conn->user);
  Curl_safefree(conn->passwd);
  Curl_safefree(conn->proxyuser);
  Curl_safefree(conn->proxypasswd);
  Curl_safefree(conn->allocptr.proxyuserpwd);
  Curl_safefree(conn->allocptr.uagent);
  Curl_safefree(conn->allocptr.userpwd);
  Curl_safefree(conn->allocptr.accept_encoding);
  Curl_safefree(conn->allocptr.rangeline);
  Curl_safefree(conn->allocptr.ref);
  Curl_safefree(conn->allocptr.host);
  Curl_safefree(conn->allocptr.cookiehost);
  Curl_safefree(conn->allocptr.rtsp_transport);
  Curl_safefree(conn->trailer);
  Curl_safefree(conn->host.rawalloc); /* host name buffer */
  Curl_safefree(conn->proxy.rawalloc); /* proxy name buffer */
  Curl_safefree(conn->master_buffer);

  Curl_llist_destroy(conn->send_pipe, NULL);
  Curl_llist_destroy(conn->recv_pipe, NULL);
  Curl_llist_destroy(conn->pend_pipe, NULL);
  Curl_llist_destroy(conn->done_pipe, NULL);

  /* possible left-overs from the async name resolvers */
#if defined(CURLRES_THREADED)
  Curl_destroy_thread_data(&conn->async);
#elif defined(CURLRES_ASYNCH)
  Curl_safefree(conn->async.hostname);
  Curl_safefree(conn->async.os_specific);
#endif

  Curl_free_ssl_config(&conn->ssl_config);

  free(conn); /* free all the connection oriented data */
}

CURLcode Curl_disconnect(struct connectdata *conn, bool dead_connection)
{
  struct SessionHandle *data;
  if(!conn)
    return CURLE_OK; /* this is closed and fine already */
  data = conn->data;

  if(!data) {
    DEBUGF(infof(data, "DISCONNECT without easy handle, ignoring\n"));
    return CURLE_OK;
  }

  if(conn->dns_entry != NULL) {
    Curl_resolv_unlock(data, conn->dns_entry);
    conn->dns_entry = NULL;
  }

#if defined(DEBUGBUILD) && defined(AGGRESIVE_TEST)
  /* scan for DNS cache entries still marked as in use */
  Curl_hash_apply(data->hostcache,
                  NULL, Curl_scan_cache_used);
#endif

  Curl_hostcache_prune(data); /* kill old DNS cache entries */

  {
    int has_host_ntlm = (conn->ntlm.state != NTLMSTATE_NONE);
    int has_proxy_ntlm = (conn->proxyntlm.state != NTLMSTATE_NONE);

    /* Authentication data is a mix of connection-related and sessionhandle-
       related stuff. NTLM is connection-related so when we close the shop
       we shall forget. */

    if (has_host_ntlm) {
      data->state.authhost.done = FALSE;
      data->state.authhost.picked =
        data->state.authhost.want;
    }

    if (has_proxy_ntlm) {
      data->state.authproxy.done = FALSE;
      data->state.authproxy.picked =
        data->state.authproxy.want;
    }

    if (has_host_ntlm || has_proxy_ntlm) {
      data->state.authproblem = FALSE;

      Curl_ntlm_cleanup(conn);
    }
  }

  /* Cleanup possible redirect junk */
  if(data->req.newurl) {
    free(data->req.newurl);
    data->req.newurl = NULL;
  }

  if(conn->handler->disconnect)
    /* This is set if protocol-specific cleanups should be made */
    conn->handler->disconnect(conn, dead_connection);

  if(-1 != conn->connectindex) {
    /* unlink ourselves! */
    infof(data, "Closing connection #%ld\n", conn->connectindex);
    if(data->state.connc)
      /* only clear the table entry if we still know in which cache we
         used to be in */
      data->state.connc->connects[conn->connectindex] = NULL;
  }

#if defined(USE_LIBIDN)
  if(conn->host.encalloc)
    idn_free(conn->host.encalloc); /* encoded host name buffer, must be freed
                                      with idn_free() since this was allocated
                                      by libidn */
  if(conn->proxy.encalloc)
    idn_free(conn->proxy.encalloc); /* encoded proxy name buffer, must be
                                       freed with idn_free() since this was
                                       allocated by libidn */
#elif defined(USE_WIN32_IDN)
  free(conn->host.encalloc); /* encoded host name buffer, must be freed with
                                idn_free() since this was allocated by
                                curl_win32_idn_to_ascii */
  if(conn->proxy.encalloc)
    free(conn->proxy.encalloc); /* encoded proxy name buffer, must be freed
                                   with idn_free() since this was allocated by
                                   curl_win32_idn_to_ascii */
#endif

  Curl_ssl_close(conn, FIRSTSOCKET);

  /* Indicate to all handles on the pipe that we're dead */
  if(Curl_isPipeliningEnabled(data)) {
    signalPipeClose(conn->send_pipe, TRUE);
    signalPipeClose(conn->recv_pipe, TRUE);
    signalPipeClose(conn->pend_pipe, TRUE);
    signalPipeClose(conn->done_pipe, FALSE);
  }

  conn_free(conn);
  data->state.current_conn = NULL;

  return CURLE_OK;
}

/*
 * This function should return TRUE if the socket is to be assumed to
 * be dead. Most commonly this happens when the server has closed the
 * connection due to inactivity.
 */
static bool SocketIsDead(curl_socket_t sock)
{
  int sval;
  bool ret_val = TRUE;

  sval = Curl_socket_ready(sock, CURL_SOCKET_BAD, 0);
  if(sval == 0)
    /* timeout */
    ret_val = FALSE;

  return ret_val;
}

#ifndef CURL_DISABLE_RTSP
/*
 * The server may send us RTP data at any point, and RTSPREQ_RECEIVE does not
 * want to block the application forever while receiving a stream. Therefore,
 * we cannot assume that an RTSP socket is dead just because it is readable.
 *
 * Instead, if it is readable, run Curl_getconnectinfo() to peek at the socket
 * and distinguish between closed and data.
 */
static bool RTSPConnIsDead(struct connectdata *check)
{
  int sval;
  bool ret_val = TRUE;

  sval = Curl_socket_ready(check->sock[FIRSTSOCKET], CURL_SOCKET_BAD, 0);
  if(sval == 0) {
    /* timeout */
    ret_val = FALSE;
  }
  else if (sval & CURL_CSELECT_ERR) {
    /* socket is in an error state */
    ret_val = TRUE;
  }
  else if (sval & CURL_CSELECT_IN) {
    /* readable with no error. could be closed or could be alive */
    curl_socket_t connectinfo =
      Curl_getconnectinfo(check->data, &check);
    if(connectinfo != CURL_SOCKET_BAD)
      ret_val = FALSE;
  }

  return ret_val;
}
#endif /* CURL_DISABLE_RTSP */

static bool IsPipeliningPossible(const struct SessionHandle *handle,
                                 const struct connectdata *conn)
{
  if((conn->handler->protocol & CURLPROTO_HTTP) &&
     handle->multi && Curl_multi_canPipeline(handle->multi) &&
     (handle->set.httpreq == HTTPREQ_GET ||
      handle->set.httpreq == HTTPREQ_HEAD) &&
     handle->set.httpversion != CURL_HTTP_VERSION_1_0)
    return TRUE;

  return FALSE;
}

bool Curl_isPipeliningEnabled(const struct SessionHandle *handle)
{
  if(handle->multi && Curl_multi_canPipeline(handle->multi))
    return TRUE;

  return FALSE;
}

CURLcode Curl_addHandleToPipeline(struct SessionHandle *data,
                                  struct curl_llist *pipeline)
{
  if(!Curl_llist_insert_next(pipeline, pipeline->tail, data))
    return CURLE_OUT_OF_MEMORY;
  return CURLE_OK;
}

int Curl_removeHandleFromPipeline(struct SessionHandle *handle,
                                  struct curl_llist *pipeline)
{
  struct curl_llist_element *curr;

  curr = pipeline->head;
  while(curr) {
    if(curr->ptr == handle) {
      Curl_llist_remove(pipeline, curr, NULL);
      return 1; /* we removed a handle */
    }
    curr = curr->next;
  }

  return 0;
}

#if 0 /* this code is saved here as it is useful for debugging purposes */
static void Curl_printPipeline(struct curl_llist *pipeline)
{
  struct curl_llist_element *curr;

  curr = pipeline->head;
  while(curr) {
    struct SessionHandle *data = (struct SessionHandle *) curr->ptr;
    infof(data, "Handle in pipeline: %s\n", data->state.path);
    curr = curr->next;
  }
}
#endif

static struct SessionHandle* gethandleathead(struct curl_llist *pipeline)
{
  struct curl_llist_element *curr = pipeline->head;
  if(curr) {
    return (struct SessionHandle *) curr->ptr;
  }

  return NULL;
}

/* remove the specified connection from all (possible) pipelines and related
   queues */
void Curl_getoff_all_pipelines(struct SessionHandle *data,
                               struct connectdata *conn)
{
  bool recv_head = (bool)(conn->readchannel_inuse &&
    (gethandleathead(conn->recv_pipe) == data));

  bool send_head = (bool)(conn->writechannel_inuse &&
    (gethandleathead(conn->send_pipe) == data));

  if(Curl_removeHandleFromPipeline(data, conn->recv_pipe) && recv_head)
    conn->readchannel_inuse = FALSE;
  if(Curl_removeHandleFromPipeline(data, conn->send_pipe) && send_head)
    conn->writechannel_inuse = FALSE;
  Curl_removeHandleFromPipeline(data, conn->pend_pipe);
  Curl_removeHandleFromPipeline(data, conn->done_pipe);
}

static void signalPipeClose(struct curl_llist *pipeline, bool pipe_broke)
{
  struct curl_llist_element *curr;

  if(!pipeline)
    return;

  curr = pipeline->head;
  while(curr) {
    struct curl_llist_element *next = curr->next;
    struct SessionHandle *data = (struct SessionHandle *) curr->ptr;

#ifdef DEBUGBUILD /* debug-only code */
    if(data->magic != CURLEASY_MAGIC_NUMBER) {
      /* MAJOR BADNESS */
      infof(data, "signalPipeClose() found BAAD easy handle\n");
    }
#endif

    if (pipe_broke)
       data->state.pipe_broke = TRUE;
    Curl_multi_handlePipeBreak(data);
    Curl_llist_remove(pipeline, curr, NULL);
    curr = next;
  }
}


/*
 * Given one filled in connection struct (named needle), this function should
 * detect if there already is one that has all the significant details
 * exactly the same and thus should be used instead.
 *
 * If there is a match, this function returns TRUE - and has marked the
 * connection as 'in-use'. It must later be called with ConnectionDone() to
 * return back to 'idle' (unused) state.
 */
static bool
ConnectionExists(struct SessionHandle *data,
                 struct connectdata *needle,
                 struct connectdata **usethis)
{
  long i;
  struct connectdata *check;
  bool canPipeline = IsPipeliningPossible(data, needle);

  for(i=0; i< data->state.connc->num; i++) {
    bool match = FALSE;
    size_t pipeLen = 0;
    /*
     * Note that if we use a HTTP proxy, we check connections to that
     * proxy and not to the actual remote server.
     */
    check = data->state.connc->connects[i];
    if(!check)
      /* NULL pointer means not filled-in entry */
      continue;

    pipeLen = check->send_pipe->size + check->recv_pipe->size;

    if(check->connectindex == -1) {
      check->connectindex = i; /* Set this appropriately since it might have
                                  been set to -1 when the easy was removed
                                  from the multi */
    }

    if(!pipeLen && !check->inuse) {
      /* The check for a dead socket makes sense only if there are no
         handles in pipeline and the connection isn't already marked in
         use */
      bool dead;
#ifndef CURL_DISABLE_RTSP
      if(check->handler->protocol & CURLPROTO_RTSP)
        /* RTSP is a special case due to RTP interleaving */
        dead = RTSPConnIsDead(check);
      else
#endif /*CURL_DISABLE_RTSP*/
        dead = SocketIsDead(check->sock[FIRSTSOCKET]);

      if(dead) {
        check->data = data;
        infof(data, "Connection #%ld seems to be dead!\n", i);

        /* disconnect resources */
        Curl_disconnect(check, /* dead_connection */ TRUE);
        data->state.connc->connects[i]=NULL; /* nothing here */

        continue;
      }
    }

    if(canPipeline) {
      /* Make sure the pipe has only GET requests */
      struct SessionHandle* sh = gethandleathead(check->send_pipe);
      struct SessionHandle* rh = gethandleathead(check->recv_pipe);
      if(sh) {
        if(!IsPipeliningPossible(sh, check))
          continue;
      }
      else if(rh) {
        if(!IsPipeliningPossible(rh, check))
          continue;
      }

#ifdef DEBUGBUILD
      if(pipeLen > MAX_PIPELINE_LENGTH) {
        infof(data, "BAD! Connection #%ld has too big pipeline!\n",
              check->connectindex);
      }
#endif
    }
    else {
      if(pipeLen > 0) {
        /* can only happen within multi handles, and means that another easy
           handle is using this connection */
        continue;
      }

#ifdef CURLRES_ASYNCH
      /* ip_addr_str[0] is NUL only if the resolving of the name hasn't
         completed yet and until then we don't re-use this connection */
      if(!check->ip_addr_str[0]) {
        infof(data,
              "Connection #%ld hasn't finished name resolve, can't reuse\n",
              check->connectindex);
        continue;
      }
#endif

      if((check->sock[FIRSTSOCKET] == CURL_SOCKET_BAD) || check->bits.close) {
        /* Don't pick a connection that hasn't connected yet or that is going
           to get closed. */
        infof(data, "Connection #%ld isn't open enough, can't reuse\n",
              check->connectindex);
#ifdef DEBUGBUILD
        if(check->recv_pipe->size > 0) {
          infof(data, "BAD! Unconnected #%ld has a non-empty recv pipeline!\n",
                check->connectindex);