url.c

     * Resume transfer at the give file position
     */
    data->set.set_resume_from = va_arg(param, long);
    break;
  case CURLOPT_RESUME_FROM_LARGE:
    /*
     * Resume transfer at the give file position
     */
    data->set.set_resume_from = va_arg(param, curl_off_t);
    break;
  case CURLOPT_DEBUGFUNCTION:
    /*
     * stderr write callback.
     */
    data->set.fdebug = va_arg(param, curl_debug_callback);
    /*
     * if the callback provided is NULL, it'll use the default callback
     */
    break;
  case CURLOPT_DEBUGDATA:
    /*
     * Set to a void * that should receive all error writes. This
     * defaults to CURLOPT_STDERR for normal operations.
     */
    data->set.debugdata = va_arg(param, void *);
    break;
  case CURLOPT_STDERR:
    /*
     * Set to a FILE * that should receive all error writes. This
     * defaults to stderr for normal operations.
     */
    data->set.err = va_arg(param, FILE *);
    if(!data->set.err)
      data->set.err = stderr;
    break;
  case CURLOPT_HEADERFUNCTION:
    /*
     * Set header write callback
     */
    data->set.fwrite_header = va_arg(param, curl_write_callback);
    break;
  case CURLOPT_WRITEFUNCTION:
    /*
     * Set data write callback
     */
    data->set.fwrite = va_arg(param, curl_write_callback);
    if(!data->set.fwrite)
      /* When set to NULL, reset to our internal default function */
      data->set.fwrite = (curl_write_callback)fwrite;
    break;
  case CURLOPT_READFUNCTION:
    /*
     * Read data callback
     */
    data->set.fread = va_arg(param, curl_read_callback);
    if(!data->set.fread)
      /* When set to NULL, reset to our internal default function */
      data->set.fread = (curl_read_callback)fread;
    break;
  case CURLOPT_SSLCERT:
    /*
     * String that holds file name of the SSL certificate to use
     */
    data->set.cert = va_arg(param, char *);
    break;
  case CURLOPT_SSLCERTTYPE:
    /*
     * String that holds file type of the SSL certificate to use
     */
    data->set.cert_type = va_arg(param, char *);
    break;
  case CURLOPT_SSLKEY:
    /*
     * String that holds file name of the SSL certificate to use
     */
    data->set.key = va_arg(param, char *);
    break;
  case CURLOPT_SSLKEYTYPE:
    /*
     * String that holds file type of the SSL certificate to use
     */
    data->set.key_type = va_arg(param, char *);
    break;
  case CURLOPT_SSLKEYPASSWD:
    /*
     * String that holds the SSL private key password.
     */
    data->set.key_passwd = va_arg(param, char *);
    break;
  case CURLOPT_SSLENGINE:
    /*
     * String that holds the SSL crypto engine.
     */
#ifdef HAVE_OPENSSL_ENGINE_H
    {
      const char *cpTemp = va_arg(param, char *);
      ENGINE     *e;
      if (cpTemp && cpTemp[0]) {
        e = ENGINE_by_id(cpTemp);
        if (e) {
          if (data->engine) {
            ENGINE_free(data->engine);
          }
          data->engine = e;
        }
        else {
          failf(data, "SSL Engine '%s' not found", cpTemp);
          return CURLE_SSL_ENGINE_NOTFOUND;
        }
      }
    }
    break;
#else
    return CURLE_SSL_ENGINE_NOTFOUND;
#endif
  case CURLOPT_SSLENGINE_DEFAULT:
    /*
     * flag to set engine as default.
     */
#ifdef HAVE_OPENSSL_ENGINE_H
    if (data->engine) {
      if (ENGINE_set_default(data->engine, ENGINE_METHOD_ALL) > 0) {
#ifdef DEBUG
        fprintf(stderr,"set default crypto engine\n");
#endif
      }
      else {
#ifdef DEBUG
        failf(data, "set default crypto engine failed");
#endif
        return CURLE_SSL_ENGINE_SETFAILED;
      }
    }
#endif
    break;
  case CURLOPT_CRLF:
    /*
     * Kludgy option to enable CRLF convertions. Subject for removal.
     */
    data->set.crlf = va_arg(param, long)?TRUE:FALSE;
    break;
  case CURLOPT_INTERFACE:
    /*
     * Set what interface to bind to when performing an operation and thus
     * what from-IP your connection will use.
     */
    data->set.device = va_arg(param, char *);
    break;
  case CURLOPT_KRB4LEVEL:
    /*
     * A string that defines the krb4 security level.
     */
    data->set.krb4_level = va_arg(param, char *);
    data->set.krb4=data->set.krb4_level?TRUE:FALSE;
    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;
  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_CAINFO:
    /*
     * Set CA info for SSL connection. Specify file name of the CA certificate
     */
    data->set.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. */
    data->set.ssl.CApath = 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 = va_arg(param, long) ? TRUE : FALSE;
    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->share->hostcache == data->hostcache)
          data->hostcache = NULL;

        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 own one if any */
          if(data->hostcache)
            Curl_hash_destroy(data->hostcache);

          data->hostcache = data->share->hostcache;
        }
        
        if(data->share->cookies) {
          /* use shared cookie list, first free own one if any */
          if (data->cookies)
            Curl_cookie_cleanup(data->cookies);
          data->cookies = data->share->cookies;
        }

        Curl_share_unlock(data, CURL_LOCK_DATA_SHARE);
        
      }

      /* check cookie list is set */
      if(!data->cookies)
        data->cookies = Curl_cookie_init(data, NULL, NULL, TRUE );
      
      /* check for host cache not needed,
       * it will be done by curl_easy_perform */ 
    }
    break;

  case CURLOPT_PROXYTYPE:
    /*
     * Set proxy type. HTTP/SOCKS4/SOCKS5
     */
    data->set.proxytype = (curl_proxytype)va_arg(param, long);
    break;

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

  case CURLOPT_HTTP200ALIASES:
    /*
     * Set a list of aliases for HTTP 200 in response header
     */
    data->set.http200aliases = va_arg(param, struct curl_slist *);
    break;

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

  case CURLOPT_FTP_SSL:
    /*
     * Make FTP transfers attempt to use SSL/TLS.
     */
    data->set.ftp_ssl = (curl_ftpssl)va_arg(param, long);
    break;

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

  default:
    /* unknown tag and its companion, just ignore: */
    return CURLE_FAILED_INIT; /* correct this */
  }
  return CURLE_OK;
}

CURLcode Curl_disconnect(struct connectdata *conn)
{
  if(!conn)
    return CURLE_OK; /* this is closed and fine already */

  /*
   * The range string is usually freed in curl_done(), but we might
   * get here *instead* if we fail prematurely. Thus we need to be able
   * to free this resource here as well.
   */
  if(conn->bits.rangestringalloc) {
    free(conn->range);
    conn->bits.rangestringalloc = FALSE;
  }

  if((conn->ntlm.state != NTLMSTATE_NONE) ||
     (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. */
    conn->data->state.authstage = 0;

  if(conn->curl_disconnect)
    /* This is set if protocol-specific cleanups should be made */
    conn->curl_disconnect(conn);

  if(-1 != conn->connectindex) {
    /* unlink ourselves! */
    infof(conn->data, "Closing connection #%d\n", conn->connectindex);
    conn->data->state.connects[conn->connectindex] = NULL;
  }

  Curl_safefree(conn->proto.generic);
  Curl_safefree(conn->newurl);
  Curl_safefree(conn->pathbuffer); /* the URL path buffer */
  Curl_safefree(conn->namebuffer); /* the URL host name buffer */
  Curl_SSL_Close(conn);

  /* 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.cookie);
  Curl_safefree(conn->allocptr.host);
  Curl_safefree(conn->allocptr.cookiehost);
  Curl_safefree(conn->proxyhost);
#if defined(USE_ARES) || defined(USE_THREADING_GETHOSTBYNAME) || \
    defined(USE_THREADING_GETADDRINFO)
  /* possible left-overs from the async name resolve */
  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 */

  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;
  fd_set check_set;
  struct timeval to;

  FD_ZERO(&check_set);
  FD_SET(sock, &check_set);

  to.tv_sec = 0;
  to.tv_usec = 0;

  sval = select(sock + 1, &check_set, 0, 0, &to);
  if(sval == 0)
    /* timeout */
    ret_val = FALSE;

  return ret_val;
}

/*
 * Given one filled in connection struct (named needle), this function should
 * detect if there already is one that have all the significant details
 * exactly the same and thus should be used instead.
 */
static bool
ConnectionExists(struct SessionHandle *data,
                 struct connectdata *needle,
                 struct connectdata **usethis)
{
  long i;
  struct connectdata *check;

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

    if((needle->protocol&PROT_SSL) != (check->protocol&PROT_SSL))
      /* don't do mixed SSL and non-SSL connections */
      continue;

    if(!needle->bits.httpproxy || needle->protocol&PROT_SSL) {
      /* The requested connection does not use a HTTP proxy or it
         uses SSL. */

      if(!(needle->protocol&PROT_SSL) && check->bits.httpproxy)
        /* we don't do SSL but the cached connection has a proxy,
           then don't match this */
        continue;

      if(strequal(needle->protostr, check->protostr) &&
         strequal(needle->hostname, check->hostname) &&
         (needle->remote_port == check->remote_port) ) {
        if(needle->protocol & PROT_SSL) {
          /* This is SSL, verify that we're using the same
             ssl options as well */
          if(!Curl_ssl_config_matches(&needle->ssl_config,
                                      &check->ssl_config)) {
            continue;
          }
        }
        if((needle->protocol & PROT_FTP) ||
           ((needle->protocol & PROT_HTTP) &&
            (needle->data->state.authwant==CURLAUTH_NTLM))) {
          /* This is FTP or HTTP+NTLM, verify that we're using the same name
             and password as well */
          if(!strequal(needle->user, check->user) ||
             !strequal(needle->passwd, check->passwd)) {
            /* one of them was different */
            continue;
          }
        }
        match = TRUE;
      }
    }
    else { /* The requested needle connection is using a proxy,
              is the checked one using the same? */
      if(check->bits.httpproxy &&
         strequal(needle->proxyhost, check->proxyhost) &&
         needle->port == check->port) {
        /* This is the same proxy connection, use it! */
        match = TRUE;
      }
    }

    if(match) {
      bool dead = SocketIsDead(check->sock[FIRSTSOCKET]);
      if(dead) {
        /*
         */
        infof(data, "Connection %d seems to be dead!\n", i);
        Curl_disconnect(check); /* disconnect resources */
        data->state.connects[i]=NULL; /* nothing here */

        /* There's no need to continue searching, because we only store
           one connection for each unique set of identifiers */
        return FALSE;
      }

      *usethis = check;
      return TRUE; /* yes, we found one to use! */
    }
  }
  return FALSE; /* no matching connecting exists */
}

/*
 * This function frees/closes a connection in the connection cache. This
 * should take the previously set policy into account when deciding which
 * of the connections to kill.
 */
static int
ConnectionKillOne(struct SessionHandle *data)
{
  long i;
  struct connectdata *conn;
  int highscore=-1;
  int connindex=-1;
  int score;
  struct timeval now;

  now = Curl_tvnow();

  for(i=0; i< data->state.numconnects; i++) {
    conn = data->state.connects[i];

    if(!conn)
      continue;

    /*
     * By using the set policy, we score each connection.
     */
    switch(data->set.closepolicy) {
    case CURLCLOSEPOLICY_LEAST_RECENTLY_USED:
    default:
      /*
       * Set higher score for the age passed since the connection
       * was used.
       */
      score = Curl_tvdiff(now, conn->now);
      break;
    case CURLCLOSEPOLICY_OLDEST:
      /*
       * Set higher score for the age passed since the connection
       * was created.
       */
      score = Curl_tvdiff(now, conn->created);
      break;
    }

    if(score > highscore) {
      highscore = score;
      connindex = i;
    }
  }
  if(connindex >= 0) {

    /* the winner gets the honour of being disconnected */
    (void) Curl_disconnect(data->state.connects[connindex]);

    /* clean the array entry */
    data->state.connects[connindex] = NULL;
  }

  return connindex; /* return the available index or -1 */
}

/*
 * The given input connection struct pointer is to be stored. If the "cache"
 * is already full, we must clean out the most suitable using the previously
 * set policy.
 *
 * The given connection should be unique. That must've been checked prior to
 * this call.
 */
static unsigned int
ConnectionStore(struct SessionHandle *data,
                struct connectdata *conn)
{
  long i;
  for(i=0; i< data->state.numconnects; i++) {
    if(!data->state.connects[i])
      break;
  }
  if(i == data->state.numconnects) {
    /* there was no room available, kill one */
    i = ConnectionKillOne(data);
    infof(data, "Connection (#%d) was killed to make room\n", i);
  }

  if(-1 != i) {
    /* only do this if a true index was returned, if -1 was returned there
       is no room in the cache for an unknown reason and we cannot store
       this there. */
    data->state.connects[i] = conn; /* fill in this */
    conn->connectindex = i; /* make the child know where the pointer to this
                               particular data is stored */
  }
  return i;
}

/*
 * This function logs in to a SOCKS5 proxy and sends the specifies the final
 * desitination server.
 */
static int handleSock5Proxy(const char *proxy_name,
                            const char *proxy_password,
                            struct connectdata *conn)
{
  /*
    According to the RFC1928, section "6.  Replies". This is what a SOCK5
    replies:

        +----+-----+-------+------+----------+----------+
        |VER | REP |  RSV  | ATYP | BND.ADDR | BND.PORT |
        +----+-----+-------+------+----------+----------+
        | 1  |  1  | X'00' |  1   | Variable |    2     |
        +----+-----+-------+------+----------+----------+

    Where:

    o  VER    protocol version: X'05'
    o  REP    Reply field:
    o  X'00' succeeded
  */

  unsigned char socksreq[600]; /* room for large user/pw (255 max each) */
  ssize_t actualread;
  ssize_t written;
  int result;
  CURLcode code;
  int sock = conn->sock[FIRSTSOCKET];

  Curl_nonblock(sock, FALSE);

  socksreq[0] = 5; /* version */
  socksreq[1] = (char)(proxy_name ? 2 : 1); /* number of methods (below) */
  socksreq[2] = 0; /* no authentication */
  socksreq[3] = 2; /* username/password */

  code = Curl_write(conn, sock, (char *)socksreq, (2 + (int)socksreq[1]),
                      &written);
  if ((code != CURLE_OK) || (written != (2 + (int)socksreq[1]))) {
    failf(conn->data, "Unable to send initial SOCKS5 request.");
    return 1;
  }

  result=Curl_read(conn, sock, (char *)socksreq, 2, &actualread);
  if ((result != CURLE_OK) || (actualread != 2)) {
    failf(conn->data, "Unable to receive initial SOCKS5 response.");
    return 1;
  }

  if (socksreq[0] != 5) {
    failf(conn->data, "Received invalid version in initial SOCKS5 response.");
    return 1;
  }
  if (socksreq[1] == 0) {
    /* Nothing to do, no authentication needed */
    ;
  }
  else if (socksreq[1] == 2) {
    /* Needs user name and password */
    int userlen, pwlen, len;

    userlen = strlen(proxy_name);
    pwlen = proxy_password?strlen(proxy_password):0;

    /*   username/password request looks like
     * +----+------+----------+------+----------+
     * |VER | ULEN |  UNAME   | PLEN |  PASSWD  |
     * +----+------+----------+------+----------+
     * | 1  |  1   | 1 to 255 |  1   | 1 to 255 |
     * +----+------+----------+------+----------+
     */
    len = 0;
    socksreq[len++] = 1;    /* username/pw subnegotiation version */
    socksreq[len++] = (char) userlen;
    memcpy(socksreq + len, proxy_name, (int) userlen);
    len += userlen;
    socksreq[len++] = (char) pwlen;
    memcpy(socksreq + len, proxy_password, (int) pwlen);
    len += pwlen;

    code = Curl_write(conn, sock, (char *)socksreq, len, &written);
    if ((code != CURLE_OK) || (len != written)) {
      failf(conn->data, "Failed to send SOCKS5 sub-negotiation request.");
      return 1;
    }

    result=Curl_read(conn, sock, (char *)socksreq, 2, &actualread);
    if ((result != CURLE_OK) || (actualread != 2)) {
      failf(conn->data, "Unable to receive SOCKS5 sub-negotiation response.");
      return 1;
    }

    if ((socksreq[0] != 5) || /* version */
        (socksreq[1] != 0)) { /* status */
      failf(conn->data, "User was rejected by the SOCKS5 server (%d %d).",
            socksreq[0], socksreq[1]);
      return 1;
    }

    /* Everything is good so far, user was authenticated! */
  }
  else {
    /* error */
    if (socksreq[1] == 1) {
      failf(conn->data,
            "SOCKS5 GSSAPI per-message authentication is not supported.");
      return 1;
    }
    else if (socksreq[1] == 255) {
      if (proxy_name[0] == 0) {
        failf(conn->data,
              "No authentication method was acceptable. (It is quite likely"
              " that the SOCKS5 server wanted a username/password, since none"
              " was supplied to the server on this connection.)");
      }
      else {
        failf(conn->data, "No authentication method was acceptable.");
      }
      return 1;
    }
    else {
      failf(conn->data,
            "Undocumented SOCKS5 mode attempted to be used by server.");
      return 1;
    }
  }

  /* Authentication is complete, now specify destination to the proxy */
  socksreq[0] = 5; /* version (SOCKS5) */
  socksreq[1] = 1; /* connect */
  socksreq[2] = 0; /* must be zero */
  socksreq[3] = 1; /* IPv4 = 1 */

  {
#ifndef ENABLE_IPV6
    struct Curl_dns_entry *dns;
    Curl_addrinfo *hp=NULL;
    int rc = Curl_resolv(conn, conn->hostname, conn->remote_port, &dns);
    
    if(rc == -1)
      return 1;

    if(rc == 1)
      /* this requires that we're in "wait for resolve" state */
      rc = Curl_wait_for_resolv(conn, &dns);
    
    /*
     * We cannot use 'hostent' as a struct that Curl_resolv() returns.  It
     * returns a Curl_addrinfo pointer that may not always look the same.
     */
    if(dns)
      hp=dns->addr;
    if (hp && hp->h_addr_list[0]) {
      socksreq[4] = ((char*)hp->h_addr_list[0])[0];
      socksreq[5] = ((char*)hp->h_addr_list[0])[1];
      socksreq[6] = ((char*)hp->h_addr_list[0])[2];
      socksreq[7] = ((char*)hp->h_addr_list[0])[3];

      Curl_resolv_unlock(conn->data, dns); /* not used anymore from now on */
    }
    else {
      failf(conn->data, "Failed to resolve \"%s\" for SOCKS5 connect.",
            conn->hostname);
      return 1;
    }
#else
    failf(conn->data,
          "%s:%d has an internal error an needs to be fixed to work",
          __FILE__, __LINE__);
    return 1;
#endif
  }

  *((unsigned short*)&socksreq[8]) = htons(conn->remote_port);

  {
    const int packetsize = 10;

    code = Curl_write(conn, sock, (char *)socksreq, packetsize, &written);
    if ((code != CURLE_OK) || (written != packetsize)) {
      failf(conn->data, "Failed to send SOCKS5 connect request.");
      return 1;
    }

    result = Curl_read(conn, sock, (char *)socksreq, packetsize, &actualread);
    if ((result != CURLE_OK) || (actualread != packetsize)) {
      failf(conn->data, "Failed to receive SOCKS5 connect request ack.");
      return 1;
    }

    if (socksreq[0] != 5) { /* version */
      failf(conn->data,
            "SOCKS5 reply has wrong version, version should be 5.");
      return 1;
    }
    if (socksreq[1] != 0) { /* Anything besides 0 is an error */
        failf(conn->data,
              "Can't complete SOCKS5 connection to %d.%d.%d.%d:%d. (%d)",
              (unsigned char)socksreq[4], (unsigned char)socksreq[5],
              (unsigned char)socksreq[6], (unsigned char)socksreq[7],
              (unsigned int)ntohs(*(unsigned short*)(&socksreq[8])),
              socksreq[1]);
        return 1;
    }
  }

  Curl_nonblock(sock, TRUE);
  return 0; /* Proxy was successful! */
}

static CURLcode ConnectPlease(struct connectdata *conn,
                              struct Curl_dns_entry *hostaddr,
                              bool *connected)
{
  CURLcode result;
  Curl_ipconnect *addr;

  /*************************************************************
   * Connect to server/proxy
   *************************************************************/
  result= Curl_connecthost(conn,
                           hostaddr,
                           conn->port,
                           &conn->sock[FIRSTSOCKET],
                           &addr,
                           connected);
  if(CURLE_OK == result) {
    /* All is cool, then we store the current information from the hostaddr
       struct to the serv_addr, as it might be needed later. The address
       returned from the function above is crucial here. */
    conn->connect_addr = hostaddr;

#ifdef ENABLE_IPV6
    conn->serv_addr = addr;
#else
    memset((char *) &conn->serv_addr, '\0', sizeof(conn->serv_addr));
    memcpy((char *)&(conn->serv_addr.sin_addr),
           (struct in_addr *)addr, sizeof(struct in_addr));
    conn->serv_addr.sin_family = hostaddr->addr->h_addrtype;
    conn->serv_addr.sin_port = htons((unsigned short)conn->port);
#endif

    if (conn->data->set.proxytype == CURLPROXY_SOCKS5) {
      return handleSock5Proxy(conn->proxyuser,
                              conn->proxypasswd,
                              conn) ?
        CURLE_COULDNT_CONNECT : CURLE_OK;
    }
    else if (conn->data->set.proxytype == CURLPROXY_HTTP) {
      /* do nothing here. handled later. */
    }
    else {
      failf(conn->data, "unknown proxytype option given");
      return CURLE_COULDNT_CONNECT;
    }
  }

  return result;
}

/*
 * verboseconnect() displays verbose information after a connect
 */
static void verboseconnect(struct connectdata *conn)
{
  struct SessionHandle *data = conn->data;
  const char *host=NULL;
  char addrbuf[NI_MAXHOST];

  /* Get a printable version of the network address. */
#ifdef ENABLE_IPV6
  struct addrinfo *ai = conn->serv_addr;
  host = Curl_printable_address(ai->ai_family, ai->ai_addr,
                                addrbuf, sizeof(addrbuf));
#else
  struct in_addr in;
  (void) memcpy(&in.s_addr, &conn->serv_addr.sin_addr, sizeof (in.s_addr));
  host = Curl_inet_ntop(AF_INET, &in, addrbuf, sizeof(addrbuf));
#endif
  infof(data, "Connected to %s (%s) port %d\n",
        conn->hostname, host?host:"", conn->port);
}

/*
 * We have discovered that the TCP connection has been successful, we can now
 * proceed with some action.
 *
 * If we're using the multi interface, this host address pointer is most
 * likely NULL at this point as we can't keep the resolved info around. This
 * may call for some reworking, like a reference counter in the struct or
 * something.
 */
CURLcode Curl_protocol_connect(struct connectdata *conn)
{
  struct SessionHandle *data = conn->data;
  CURLcode result=CURLE_OK;

  if(conn->bits.tcpconnect)
    /* We already are connected, get back. This may happen when the connect
       worked fine in the first call, like when we connect to a local server
       or proxy. */
    return CURLE_OK;

  Curl_pgrsTime(data, TIMER_CONNECT); /* connect done */

  if(data->set.verbose)
    verboseconnect(conn);

  if(conn->curl_connect) {
    /* is there a protocol-specific connect() procedure? */

    /* set start time here for timeout purposes in the
     * connect procedure, it is later set again for the
     * progress meter purpose */
    conn->now = Curl_tvnow();

    /* Call the protocol-specific connect function */
    result = conn->curl_connect(conn);
  }

  return result; /* pass back status */
}

/**
 * CreateConnection() sets up a new connectdata struct, or re-uses an already
 * existing one, and resolves host name.
 *
 * if this function returns CURLE_OK and *async is set to TRUE, the resolve
 * response will be coming asynchronously. If *async is FALSE, the name is
 * already resolved.
 *
 * @param data The sessionhandle pointer
 * @param in_connect is set to the next connection data pointer
 * @param addr is set to the new dns entry for this connection
 * @param async is set TRUE/FALSE depending on the nature of this lookup
 * @return CURLcode
 * @see SetupConnection()
 */

static CURLcode CreateConnection(struct SessionHandle *data,
                                 struct connectdata **in_connect,
                                 struct Curl_dns_entry **addr,
                                 bool *async)
{
  char *tmp;
  CURLcode result=CURLE_OK;
  char resumerange[40]="";
  struct connectdata *conn;
  struct connectdata *conn_temp;
  int urllen;
  struct Curl_dns_entry *hostaddr;
#ifdef HAVE_ALARM
  unsigned int prev_alarm=0;
#endif
  char endbracket;
  char user[MAX_CURL_USER_LENGTH];
  char passwd[MAX_CURL_PASSWORD_LENGTH];
  int rc;
  bool reuse;

#ifdef HAVE_SIGACTION
  struct sigaction keep_sigact;   /* store the old struct here */
  bool keep_copysig=FALSE;        /* did copy it? */
#else
#ifdef HAVE_SIGNAL
  void *keep_sigact;              /* store the old handler here */
#endif
#endif

  *addr = NULL; /* nothing yet */
  *async = FALSE;