--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/connect.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,1557 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, 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 https://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.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h> /* <netinet/tcp.h> may need it */
+#endif
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h> /* for sockaddr_un */
+#endif
+#ifdef HAVE_LINUX_TCP_H
+#include <linux/tcp.h>
+#elif defined(HAVE_NETINET_TCP_H)
+#include <netinet/tcp.h>
+#endif
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+#ifdef HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+
+#if (defined(HAVE_IOCTL_FIONBIO) && defined(NETWARE))
+#include <sys/filio.h>
+#endif
+#ifdef NETWARE
+#undef in_addr_t
+#define in_addr_t unsigned long
+#endif
+#ifdef __VMS
+#include <in.h>
+#include <inet.h>
+#endif
+
+#include "urldata.h"
+#include "sendf.h"
+#include "if2ip.h"
+#include "strerror.h"
+#include "connect.h"
+#include "select.h"
+#include "url.h" /* for Curl_safefree() */
+#include "multiif.h"
+#include "sockaddr.h" /* required for Curl_sockaddr_storage */
+#include "inet_ntop.h"
+#include "inet_pton.h"
+#include "vtls/vtls.h" /* for Curl_ssl_check_cxn() */
+#include "progress.h"
+#include "warnless.h"
+#include "conncache.h"
+#include "multihandle.h"
+#include "system_win32.h"
+#include "quic.h"
+#include "socks.h"
+
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+#ifdef __SYMBIAN32__
+/* This isn't actually supported under Symbian OS */
+#undef SO_NOSIGPIPE
+#endif
+
+static bool verifyconnect(curl_socket_t sockfd, int *error);
+
+#if defined(__DragonFly__) || defined(HAVE_WINSOCK_H)
+/* DragonFlyBSD and Windows use millisecond units */
+#define KEEPALIVE_FACTOR(x) (x *= 1000)
+#else
+#define KEEPALIVE_FACTOR(x)
+#endif
+
+#if defined(HAVE_WINSOCK2_H) && !defined(SIO_KEEPALIVE_VALS)
+#define SIO_KEEPALIVE_VALS    _WSAIOW(IOC_VENDOR,4)
+
+struct tcp_keepalive {
+  u_long onoff;
+  u_long keepalivetime;
+  u_long keepaliveinterval;
+};
+#endif
+
+static void
+tcpkeepalive(struct Curl_easy *data,
+             curl_socket_t sockfd)
+{
+  int optval = data->set.tcp_keepalive?1:0;
+
+  /* only set IDLE and INTVL if setting KEEPALIVE is successful */
+  if(setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE,
+        (void *)&optval, sizeof(optval)) < 0) {
+    infof(data, "Failed to set SO_KEEPALIVE on fd %d\n", sockfd);
+  }
+  else {
+#if defined(SIO_KEEPALIVE_VALS)
+    struct tcp_keepalive vals;
+    DWORD dummy;
+    vals.onoff = 1;
+    optval = curlx_sltosi(data->set.tcp_keepidle);
+    KEEPALIVE_FACTOR(optval);
+    vals.keepalivetime = optval;
+    optval = curlx_sltosi(data->set.tcp_keepintvl);
+    KEEPALIVE_FACTOR(optval);
+    vals.keepaliveinterval = optval;
+    if(WSAIoctl(sockfd, SIO_KEEPALIVE_VALS, (LPVOID) &vals, sizeof(vals),
+                NULL, 0, &dummy, NULL, NULL) != 0) {
+      infof(data, "Failed to set SIO_KEEPALIVE_VALS on fd %d: %d\n",
+            (int)sockfd, WSAGetLastError());
+    }
+#else
+#ifdef TCP_KEEPIDLE
+    optval = curlx_sltosi(data->set.tcp_keepidle);
+    KEEPALIVE_FACTOR(optval);
+    if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPIDLE,
+          (void *)&optval, sizeof(optval)) < 0) {
+      infof(data, "Failed to set TCP_KEEPIDLE on fd %d\n", sockfd);
+    }
+#endif
+#ifdef TCP_KEEPINTVL
+    optval = curlx_sltosi(data->set.tcp_keepintvl);
+    KEEPALIVE_FACTOR(optval);
+    if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPINTVL,
+          (void *)&optval, sizeof(optval)) < 0) {
+      infof(data, "Failed to set TCP_KEEPINTVL on fd %d\n", sockfd);
+    }
+#endif
+#ifdef TCP_KEEPALIVE
+    /* Mac OS X style */
+    optval = curlx_sltosi(data->set.tcp_keepidle);
+    KEEPALIVE_FACTOR(optval);
+    if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPALIVE,
+          (void *)&optval, sizeof(optval)) < 0) {
+      infof(data, "Failed to set TCP_KEEPALIVE on fd %d\n", sockfd);
+    }
+#endif
+#endif
+  }
+}
+
+static CURLcode
+singleipconnect(struct connectdata *conn,
+                const Curl_addrinfo *ai, /* start connecting to this */
+                int sockindex);          /* 0 or 1 among the temp ones */
+
+/*
+ * Curl_timeleft() returns the amount of milliseconds left allowed for the
+ * transfer/connection. If the value is negative, the timeout time has already
+ * elapsed.
+ *
+ * The start time is stored in progress.t_startsingle - as set with
+ * Curl_pgrsTime(..., TIMER_STARTSINGLE);
+ *
+ * If 'nowp' is non-NULL, it points to the current time.
+ * 'duringconnect' is FALSE if not during a connect, as then of course the
+ * connect timeout is not taken into account!
+ *
+ * @unittest: 1303
+ */
+timediff_t Curl_timeleft(struct Curl_easy *data,
+                         struct curltime *nowp,
+                         bool duringconnect)
+{
+  int timeout_set = 0;
+  timediff_t timeout_ms = duringconnect?DEFAULT_CONNECT_TIMEOUT:0;
+  struct curltime now;
+
+  /* if a timeout is set, use the most restrictive one */
+
+  if(data->set.timeout > 0)
+    timeout_set |= 1;
+  if(duringconnect && (data->set.connecttimeout > 0))
+    timeout_set |= 2;
+
+  switch(timeout_set) {
+  case 1:
+    timeout_ms = data->set.timeout;
+    break;
+  case 2:
+    timeout_ms = data->set.connecttimeout;
+    break;
+  case 3:
+    if(data->set.timeout < data->set.connecttimeout)
+      timeout_ms = data->set.timeout;
+    else
+      timeout_ms = data->set.connecttimeout;
+    break;
+  default:
+    /* use the default */
+    if(!duringconnect)
+      /* if we're not during connect, there's no default timeout so if we're
+         at zero we better just return zero and not make it a negative number
+         by the math below */
+      return 0;
+    break;
+  }
+
+  if(!nowp) {
+    now = Curl_now();
+    nowp = &now;
+  }
+
+  /* subtract elapsed time */
+  if(duringconnect)
+    /* since this most recent connect started */
+    timeout_ms -= Curl_timediff(*nowp, data->progress.t_startsingle);
+  else
+    /* since the entire operation started */
+    timeout_ms -= Curl_timediff(*nowp, data->progress.t_startop);
+  if(!timeout_ms)
+    /* avoid returning 0 as that means no timeout! */
+    return -1;
+
+  return timeout_ms;
+}
+
+static CURLcode bindlocal(struct connectdata *conn,
+                          curl_socket_t sockfd, int af, unsigned int scope)
+{
+  struct Curl_easy *data = conn->data;
+
+  struct Curl_sockaddr_storage sa;
+  struct sockaddr *sock = (struct sockaddr *)&sa;  /* bind to this address */
+  curl_socklen_t sizeof_sa = 0; /* size of the data sock points to */
+  struct sockaddr_in *si4 = (struct sockaddr_in *)&sa;
+#ifdef ENABLE_IPV6
+  struct sockaddr_in6 *si6 = (struct sockaddr_in6 *)&sa;
+#endif
+
+  struct Curl_dns_entry *h = NULL;
+  unsigned short port = data->set.localport; /* use this port number, 0 for
+                                                "random" */
+  /* how many port numbers to try to bind to, increasing one at a time */
+  int portnum = data->set.localportrange;
+  const char *dev = data->set.str[STRING_DEVICE];
+  int error;
+
+  /*************************************************************
+   * Select device to bind socket to
+   *************************************************************/
+  if(!dev && !port)
+    /* no local kind of binding was requested */
+    return CURLE_OK;
+
+  memset(&sa, 0, sizeof(struct Curl_sockaddr_storage));
+
+  if(dev && (strlen(dev)<255) ) {
+    char myhost[256] = "";
+    int done = 0; /* -1 for error, 1 for address found */
+    bool is_interface = FALSE;
+    bool is_host = FALSE;
+    static const char *if_prefix = "if!";
+    static const char *host_prefix = "host!";
+
+    if(strncmp(if_prefix, dev, strlen(if_prefix)) == 0) {
+      dev += strlen(if_prefix);
+      is_interface = TRUE;
+    }
+    else if(strncmp(host_prefix, dev, strlen(host_prefix)) == 0) {
+      dev += strlen(host_prefix);
+      is_host = TRUE;
+    }
+
+    /* interface */
+    if(!is_host) {
+#ifdef SO_BINDTODEVICE
+      /* I am not sure any other OSs than Linux that provide this feature,
+       * and at the least I cannot test. --Ben
+       *
+       * This feature allows one to tightly bind the local socket to a
+       * particular interface.  This will force even requests to other
+       * local interfaces to go out the external interface.
+       *
+       *
+       * Only bind to the interface when specified as interface, not just
+       * as a hostname or ip address.
+       *
+       * interface might be a VRF, eg: vrf-blue, which means it cannot be
+       * converted to an IP address and would fail Curl_if2ip. Simply try
+       * to use it straight away.
+       */
+      if(setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,
+                    dev, (curl_socklen_t)strlen(dev) + 1) == 0) {
+        /* This is typically "errno 1, error: Operation not permitted" if
+         * you're not running as root or another suitable privileged
+         * user.
+         * If it succeeds it means the parameter was a valid interface and
+         * not an IP address. Return immediately.
+         */
+        return CURLE_OK;
+      }
+#endif
+
+      switch(Curl_if2ip(af, scope, conn->scope_id, dev,
+                        myhost, sizeof(myhost))) {
+        case IF2IP_NOT_FOUND:
+          if(is_interface) {
+            /* Do not fall back to treating it as a host name */
+            failf(data, "Couldn't bind to interface '%s'", dev);
+            return CURLE_INTERFACE_FAILED;
+          }
+          break;
+        case IF2IP_AF_NOT_SUPPORTED:
+          /* Signal the caller to try another address family if available */
+          return CURLE_UNSUPPORTED_PROTOCOL;
+        case IF2IP_FOUND:
+          is_interface = TRUE;
+          /*
+           * We now have the numerical IP address in the 'myhost' buffer
+           */
+          infof(data, "Local Interface %s is ip %s using address family %i\n",
+                dev, myhost, af);
+          done = 1;
+          break;
+      }
+    }
+    if(!is_interface) {
+      /*
+       * This was not an interface, resolve the name as a host name
+       * or IP number
+       *
+       * Temporarily force name resolution to use only the address type
+       * of the connection. The resolve functions should really be changed
+       * to take a type parameter instead.
+       */
+      long ipver = conn->ip_version;
+      int rc;
+
+      if(af == AF_INET)
+        conn->ip_version = CURL_IPRESOLVE_V4;
+#ifdef ENABLE_IPV6
+      else if(af == AF_INET6)
+        conn->ip_version = CURL_IPRESOLVE_V6;
+#endif
+
+      rc = Curl_resolv(conn, dev, 0, FALSE, &h);
+      if(rc == CURLRESOLV_PENDING)
+        (void)Curl_resolver_wait_resolv(conn, &h);
+      conn->ip_version = ipver;
+
+      if(h) {
+        /* convert the resolved address, sizeof myhost >= INET_ADDRSTRLEN */
+        Curl_printable_address(h->addr, myhost, sizeof(myhost));
+        infof(data, "Name '%s' family %i resolved to '%s' family %i\n",
+              dev, af, myhost, h->addr->ai_family);
+        Curl_resolv_unlock(data, h);
+        if(af != h->addr->ai_family) {
+          /* bad IP version combo, signal the caller to try another address
+             family if available */
+          return CURLE_UNSUPPORTED_PROTOCOL;
+        }
+        done = 1;
+      }
+      else {
+        /*
+         * provided dev was no interface (or interfaces are not supported
+         * e.g. solaris) no ip address and no domain we fail here
+         */
+        done = -1;
+      }
+    }
+
+    if(done > 0) {
+#ifdef ENABLE_IPV6
+      /* IPv6 address */
+      if(af == AF_INET6) {
+#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
+        char *scope_ptr = strchr(myhost, '%');
+        if(scope_ptr)
+          *(scope_ptr++) = 0;
+#endif
+        if(Curl_inet_pton(AF_INET6, myhost, &si6->sin6_addr) > 0) {
+          si6->sin6_family = AF_INET6;
+          si6->sin6_port = htons(port);
+#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
+          if(scope_ptr)
+            /* The "myhost" string either comes from Curl_if2ip or from
+               Curl_printable_address. The latter returns only numeric scope
+               IDs and the former returns none at all.  So the scope ID, if
+               present, is known to be numeric */
+            si6->sin6_scope_id = atoi(scope_ptr);
+#endif
+        }
+        sizeof_sa = sizeof(struct sockaddr_in6);
+      }
+      else
+#endif
+      /* IPv4 address */
+      if((af == AF_INET) &&
+         (Curl_inet_pton(AF_INET, myhost, &si4->sin_addr) > 0)) {
+        si4->sin_family = AF_INET;
+        si4->sin_port = htons(port);
+        sizeof_sa = sizeof(struct sockaddr_in);
+      }
+    }
+
+    if(done < 1) {
+      /* errorbuf is set false so failf will overwrite any message already in
+         the error buffer, so the user receives this error message instead of a
+         generic resolve error. */
+      data->state.errorbuf = FALSE;
+      failf(data, "Couldn't bind to '%s'", dev);
+      return CURLE_INTERFACE_FAILED;
+    }
+  }
+  else {
+    /* no device was given, prepare sa to match af's needs */
+#ifdef ENABLE_IPV6
+    if(af == AF_INET6) {
+      si6->sin6_family = AF_INET6;
+      si6->sin6_port = htons(port);
+      sizeof_sa = sizeof(struct sockaddr_in6);
+    }
+    else
+#endif
+    if(af == AF_INET) {
+      si4->sin_family = AF_INET;
+      si4->sin_port = htons(port);
+      sizeof_sa = sizeof(struct sockaddr_in);
+    }
+  }
+
+  for(;;) {
+    if(bind(sockfd, sock, sizeof_sa) >= 0) {
+      /* we succeeded to bind */
+      struct Curl_sockaddr_storage add;
+      curl_socklen_t size = sizeof(add);
+      memset(&add, 0, sizeof(struct Curl_sockaddr_storage));
+      if(getsockname(sockfd, (struct sockaddr *) &add, &size) < 0) {
+        char buffer[STRERROR_LEN];
+        data->state.os_errno = error = SOCKERRNO;
+        failf(data, "getsockname() failed with errno %d: %s",
+              error, Curl_strerror(error, buffer, sizeof(buffer)));
+        return CURLE_INTERFACE_FAILED;
+      }
+      infof(data, "Local port: %hu\n", port);
+      conn->bits.bound = TRUE;
+      return CURLE_OK;
+    }
+
+    if(--portnum > 0) {
+      infof(data, "Bind to local port %hu failed, trying next\n", port);
+      port++; /* try next port */
+      /* We re-use/clobber the port variable here below */
+      if(sock->sa_family == AF_INET)
+        si4->sin_port = ntohs(port);
+#ifdef ENABLE_IPV6
+      else
+        si6->sin6_port = ntohs(port);
+#endif
+    }
+    else
+      break;
+  }
+  {
+    char buffer[STRERROR_LEN];
+    data->state.os_errno = error = SOCKERRNO;
+    failf(data, "bind failed with errno %d: %s",
+          error, Curl_strerror(error, buffer, sizeof(buffer)));
+  }
+
+  return CURLE_INTERFACE_FAILED;
+}
+
+/*
+ * verifyconnect() returns TRUE if the connect really has happened.
+ */
+static bool verifyconnect(curl_socket_t sockfd, int *error)
+{
+  bool rc = TRUE;
+#ifdef SO_ERROR
+  int err = 0;
+  curl_socklen_t errSize = sizeof(err);
+
+#ifdef WIN32
+  /*
+   * In October 2003 we effectively nullified this function on Windows due to
+   * problems with it using all CPU in multi-threaded cases.
+   *
+   * In May 2004, we bring it back to offer more info back on connect failures.
+   * Gisle Vanem could reproduce the former problems with this function, but
+   * could avoid them by adding this SleepEx() call below:
+   *
+   *    "I don't have Rational Quantify, but the hint from his post was
+   *    ntdll::NtRemoveIoCompletion(). So I'd assume the SleepEx (or maybe
+   *    just Sleep(0) would be enough?) would release whatever
+   *    mutex/critical-section the ntdll call is waiting on.
+   *
+   *    Someone got to verify this on Win-NT 4.0, 2000."
+   */
+
+#ifdef _WIN32_WCE
+  Sleep(0);
+#else
+  SleepEx(0, FALSE);
+#endif
+
+#endif
+
+  if(0 != getsockopt(sockfd, SOL_SOCKET, SO_ERROR, (void *)&err, &errSize))
+    err = SOCKERRNO;
+#ifdef _WIN32_WCE
+  /* Old WinCE versions don't support SO_ERROR */
+  if(WSAENOPROTOOPT == err) {
+    SET_SOCKERRNO(0);
+    err = 0;
+  }
+#endif
+#if defined(EBADIOCTL) && defined(__minix)
+  /* Minix 3.1.x doesn't support getsockopt on UDP sockets */
+  if(EBADIOCTL == err) {
+    SET_SOCKERRNO(0);
+    err = 0;
+  }
+#endif
+  if((0 == err) || (EISCONN == err))
+    /* we are connected, awesome! */
+    rc = TRUE;
+  else
+    /* This wasn't a successful connect */
+    rc = FALSE;
+  if(error)
+    *error = err;
+#else
+  (void)sockfd;
+  if(error)
+    *error = SOCKERRNO;
+#endif
+  return rc;
+}
+
+/* Used within the multi interface. Try next IP address, return TRUE if no
+   more address exists or error */
+static CURLcode trynextip(struct connectdata *conn,
+                          int sockindex,
+                          int tempindex)
+{
+  const int other = tempindex ^ 1;
+  CURLcode result = CURLE_COULDNT_CONNECT;
+
+  /* First clean up after the failed socket.
+     Don't close it yet to ensure that the next IP's socket gets a different
+     file descriptor, which can prevent bugs when the curl_multi_socket_action
+     interface is used with certain select() replacements such as kqueue. */
+  curl_socket_t fd_to_close = conn->tempsock[tempindex];
+  conn->tempsock[tempindex] = CURL_SOCKET_BAD;
+
+  if(sockindex == FIRSTSOCKET) {
+    Curl_addrinfo *ai = NULL;
+    int family = AF_UNSPEC;
+
+    if(conn->tempaddr[tempindex]) {
+      /* find next address in the same protocol family */
+      family = conn->tempaddr[tempindex]->ai_family;
+      ai = conn->tempaddr[tempindex]->ai_next;
+    }
+#ifdef ENABLE_IPV6
+    else if(conn->tempaddr[0]) {
+      /* happy eyeballs - try the other protocol family */
+      int firstfamily = conn->tempaddr[0]->ai_family;
+      family = (firstfamily == AF_INET) ? AF_INET6 : AF_INET;
+      ai = conn->tempaddr[0]->ai_next;
+    }
+#endif
+
+    while(ai) {
+      if(conn->tempaddr[other]) {
+        /* we can safely skip addresses of the other protocol family */
+        while(ai && ai->ai_family != family)
+          ai = ai->ai_next;
+      }
+
+      if(ai) {
+        result = singleipconnect(conn, ai, tempindex);
+        if(result == CURLE_COULDNT_CONNECT) {
+          ai = ai->ai_next;
+          continue;
+        }
+
+        conn->tempaddr[tempindex] = ai;
+      }
+      break;
+    }
+  }
+
+  if(fd_to_close != CURL_SOCKET_BAD)
+    Curl_closesocket(conn, fd_to_close);
+
+  return result;
+}
+
+/* Copies connection info into the session handle to make it available
+   when the session handle is no longer associated with a connection. */
+void Curl_persistconninfo(struct connectdata *conn)
+{
+  memcpy(conn->data->info.conn_primary_ip, conn->primary_ip, MAX_IPADR_LEN);
+  memcpy(conn->data->info.conn_local_ip, conn->local_ip, MAX_IPADR_LEN);
+  conn->data->info.conn_scheme = conn->handler->scheme;
+  conn->data->info.conn_protocol = conn->handler->protocol;
+  conn->data->info.conn_primary_port = conn->primary_port;
+  conn->data->info.conn_local_port = conn->local_port;
+}
+
+/* retrieves ip address and port from a sockaddr structure.
+   note it calls Curl_inet_ntop which sets errno on fail, not SOCKERRNO. */
+bool Curl_addr2string(struct sockaddr *sa, curl_socklen_t salen,
+                      char *addr, long *port)
+{
+  struct sockaddr_in *si = NULL;
+#ifdef ENABLE_IPV6
+  struct sockaddr_in6 *si6 = NULL;
+#endif
+#if defined(HAVE_SYS_UN_H) && defined(AF_UNIX)
+  struct sockaddr_un *su = NULL;
+#else
+  (void)salen;
+#endif
+
+  switch(sa->sa_family) {
+    case AF_INET:
+      si = (struct sockaddr_in *)(void *) sa;
+      if(Curl_inet_ntop(sa->sa_family, &si->sin_addr,
+                        addr, MAX_IPADR_LEN)) {
+        unsigned short us_port = ntohs(si->sin_port);
+        *port = us_port;
+        return TRUE;
+      }
+      break;
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      si6 = (struct sockaddr_in6 *)(void *) sa;
+      if(Curl_inet_ntop(sa->sa_family, &si6->sin6_addr,
+                        addr, MAX_IPADR_LEN)) {
+        unsigned short us_port = ntohs(si6->sin6_port);
+        *port = us_port;
+        return TRUE;
+      }
+      break;
+#endif
+#if defined(HAVE_SYS_UN_H) && defined(AF_UNIX)
+    case AF_UNIX:
+      if(salen > sizeof(sa_family_t)) {
+        su = (struct sockaddr_un*)sa;
+        msnprintf(addr, MAX_IPADR_LEN, "%s", su->sun_path);
+      }
+      else
+        addr[0] = 0; /* socket with no name */
+      *port = 0;
+      return TRUE;
+#endif
+    default:
+      break;
+  }
+
+  addr[0] = '\0';
+  *port = 0;
+  errno = EAFNOSUPPORT;
+  return FALSE;
+}
+
+/* retrieves the start/end point information of a socket of an established
+   connection */
+void Curl_updateconninfo(struct connectdata *conn, curl_socket_t sockfd)
+{
+  if(conn->transport != TRNSPRT_TCP)
+    /* there's no TCP connection! */
+    return;
+
+#if defined(HAVE_GETPEERNAME) || defined(HAVE_GETSOCKNAME)
+  if(!conn->bits.reuse && !conn->bits.tcp_fastopen) {
+    struct Curl_easy *data = conn->data;
+    char buffer[STRERROR_LEN];
+    struct Curl_sockaddr_storage ssrem;
+    struct Curl_sockaddr_storage ssloc;
+    curl_socklen_t plen;
+    curl_socklen_t slen;
+#ifdef HAVE_GETPEERNAME
+    plen = sizeof(struct Curl_sockaddr_storage);
+    if(getpeername(sockfd, (struct sockaddr*) &ssrem, &plen)) {
+      int error = SOCKERRNO;
+      failf(data, "getpeername() failed with errno %d: %s",
+            error, Curl_strerror(error, buffer, sizeof(buffer)));
+      return;
+    }
+#endif
+#ifdef HAVE_GETSOCKNAME
+    slen = sizeof(struct Curl_sockaddr_storage);
+    memset(&ssloc, 0, sizeof(ssloc));
+    if(getsockname(sockfd, (struct sockaddr*) &ssloc, &slen)) {
+      int error = SOCKERRNO;
+      failf(data, "getsockname() failed with errno %d: %s",
+            error, Curl_strerror(error, buffer, sizeof(buffer)));
+      return;
+    }
+#endif
+#ifdef HAVE_GETPEERNAME
+    if(!Curl_addr2string((struct sockaddr*)&ssrem, plen,
+                         conn->primary_ip, &conn->primary_port)) {
+      failf(data, "ssrem inet_ntop() failed with errno %d: %s",
+            errno, Curl_strerror(errno, buffer, sizeof(buffer)));
+      return;
+    }
+    memcpy(conn->ip_addr_str, conn->primary_ip, MAX_IPADR_LEN);
+#endif
+#ifdef HAVE_GETSOCKNAME
+    if(!Curl_addr2string((struct sockaddr*)&ssloc, slen,
+                         conn->local_ip, &conn->local_port)) {
+      failf(data, "ssloc inet_ntop() failed with errno %d: %s",
+            errno, Curl_strerror(errno, buffer, sizeof(buffer)));
+      return;
+    }
+#endif
+  }
+#else /* !HAVE_GETSOCKNAME && !HAVE_GETPEERNAME */
+  (void)sockfd; /* unused */
+#endif
+
+  /* persist connection info in session handle */
+  Curl_persistconninfo(conn);
+}
+
+/* after a TCP connection to the proxy has been verified, this function does
+   the next magic step.
+
+   Note: this function's sub-functions call failf()
+
+*/
+static CURLcode connected_proxy(struct connectdata *conn, int sockindex)
+{
+  CURLcode result = CURLE_OK;
+
+  if(conn->bits.socksproxy) {
+#ifndef CURL_DISABLE_PROXY
+    /* for the secondary socket (FTP), use the "connect to host"
+     * but ignore the "connect to port" (use the secondary port)
+     */
+    const char * const host = conn->bits.httpproxy ?
+                              conn->http_proxy.host.name :
+                              conn->bits.conn_to_host ?
+                              conn->conn_to_host.name :
+                              sockindex == SECONDARYSOCKET ?
+                              conn->secondaryhostname : conn->host.name;
+    const int port = conn->bits.httpproxy ? (int)conn->http_proxy.port :
+                     sockindex == SECONDARYSOCKET ? conn->secondary_port :
+                     conn->bits.conn_to_port ? conn->conn_to_port :
+                     conn->remote_port;
+    conn->bits.socksproxy_connecting = TRUE;
+    switch(conn->socks_proxy.proxytype) {
+    case CURLPROXY_SOCKS5:
+    case CURLPROXY_SOCKS5_HOSTNAME:
+      result = Curl_SOCKS5(conn->socks_proxy.user, conn->socks_proxy.passwd,
+                         host, port, sockindex, conn);
+      break;
+
+    case CURLPROXY_SOCKS4:
+    case CURLPROXY_SOCKS4A:
+      result = Curl_SOCKS4(conn->socks_proxy.user, host, port, sockindex,
+                           conn);
+      break;
+
+    default:
+      failf(conn->data, "unknown proxytype option given");
+      result = CURLE_COULDNT_CONNECT;
+    } /* switch proxytype */
+    conn->bits.socksproxy_connecting = FALSE;
+#else
+  (void)sockindex;
+#endif /* CURL_DISABLE_PROXY */
+  }
+
+  return result;
+}
+
+/*
+ * Curl_is_connected() checks if the socket has connected.
+ */
+
+CURLcode Curl_is_connected(struct connectdata *conn,
+                           int sockindex,
+                           bool *connected)
+{
+  struct Curl_easy *data = conn->data;
+  CURLcode result = CURLE_OK;
+  timediff_t allow;
+  int error = 0;
+  struct curltime now;
+  int rc;
+  int i;
+
+  DEBUGASSERT(sockindex >= FIRSTSOCKET && sockindex <= SECONDARYSOCKET);
+
+  *connected = FALSE; /* a very negative world view is best */
+
+  if(conn->bits.tcpconnect[sockindex]) {
+    /* we are connected already! */
+    *connected = TRUE;
+    return CURLE_OK;
+  }
+
+  now = Curl_now();
+
+  /* figure out how long time we have left to connect */
+  allow = Curl_timeleft(data, &now, TRUE);
+
+  if(allow < 0) {
+    /* time-out, bail out, go home */
+    failf(data, "Connection time-out");
+    return CURLE_OPERATION_TIMEDOUT;
+  }
+
+  for(i = 0; i<2; i++) {
+    const int other = i ^ 1;
+    if(conn->tempsock[i] == CURL_SOCKET_BAD)
+      continue;
+
+#ifdef ENABLE_QUIC
+    if(conn->transport == TRNSPRT_QUIC) {
+      result = Curl_quic_is_connected(conn, i, connected);
+      if(result) {
+        error = SOCKERRNO;
+        goto error;
+      }
+      if(*connected) {
+        /* use this socket from now on */
+        conn->sock[sockindex] = conn->tempsock[i];
+        conn->ip_addr = conn->tempaddr[i];
+        conn->tempsock[i] = CURL_SOCKET_BAD;
+        connkeep(conn, "HTTP/3 default");
+      }
+      return result;
+    }
+#endif
+
+#ifdef mpeix
+    /* Call this function once now, and ignore the results. We do this to
+       "clear" the error state on the socket so that we can later read it
+       reliably. This is reported necessary on the MPE/iX operating system. */
+    (void)verifyconnect(conn->tempsock[i], NULL);
+#endif
+
+    /* check socket for connect */
+    rc = SOCKET_WRITABLE(conn->tempsock[i], 0);
+
+    if(rc == 0) { /* no connection yet */
+      error = 0;
+      if(Curl_timediff(now, conn->connecttime) >= conn->timeoutms_per_addr) {
+        infof(data, "After %" CURL_FORMAT_TIMEDIFF_T
+              "ms connect time, move on!\n", conn->timeoutms_per_addr);
+        error = ETIMEDOUT;
+      }
+
+      /* should we try another protocol family? */
+      if(i == 0 && conn->tempaddr[1] == NULL &&
+         (Curl_timediff(now, conn->connecttime) >=
+          data->set.happy_eyeballs_timeout)) {
+        trynextip(conn, sockindex, 1);
+      }
+    }
+    else if(rc == CURL_CSELECT_OUT || conn->bits.tcp_fastopen) {
+      if(verifyconnect(conn->tempsock[i], &error)) {
+        /* we are connected with TCP, awesome! */
+
+        /* use this socket from now on */
+        conn->sock[sockindex] = conn->tempsock[i];
+        conn->ip_addr = conn->tempaddr[i];
+        conn->tempsock[i] = CURL_SOCKET_BAD;
+#ifdef ENABLE_IPV6
+        conn->bits.ipv6 = (conn->ip_addr->ai_family == AF_INET6)?TRUE:FALSE;
+#endif
+
+        /* close the other socket, if open */
+        if(conn->tempsock[other] != CURL_SOCKET_BAD) {
+          Curl_closesocket(conn, conn->tempsock[other]);
+          conn->tempsock[other] = CURL_SOCKET_BAD;
+        }
+
+        /* see if we need to do any proxy magic first once we connected */
+        result = connected_proxy(conn, sockindex);
+        if(result)
+          return result;
+
+        conn->bits.tcpconnect[sockindex] = TRUE;
+
+        *connected = TRUE;
+        if(sockindex == FIRSTSOCKET)
+          Curl_pgrsTime(data, TIMER_CONNECT); /* connect done */
+        Curl_updateconninfo(conn, conn->sock[sockindex]);
+        Curl_verboseconnect(conn);
+
+        return CURLE_OK;
+      }
+      infof(data, "Connection failed\n");
+    }
+    else if(rc & CURL_CSELECT_ERR)
+      (void)verifyconnect(conn->tempsock[i], &error);
+
+#ifdef ENABLE_QUIC
+    error:
+#endif
+    /*
+     * The connection failed here, we should attempt to connect to the "next
+     * address" for the given host. But first remember the latest error.
+     */
+    if(error) {
+      data->state.os_errno = error;
+      SET_SOCKERRNO(error);
+      if(conn->tempaddr[i]) {
+        CURLcode status;
+        char ipaddress[MAX_IPADR_LEN];
+        char buffer[STRERROR_LEN];
+        Curl_printable_address(conn->tempaddr[i], ipaddress, MAX_IPADR_LEN);
+        infof(data, "connect to %s port %ld failed: %s\n",
+              ipaddress, conn->port,
+              Curl_strerror(error, buffer, sizeof(buffer)));
+
+        conn->timeoutms_per_addr = conn->tempaddr[i]->ai_next == NULL ?
+          allow : allow / 2;
+
+        status = trynextip(conn, sockindex, i);
+        if((status != CURLE_COULDNT_CONNECT) ||
+           conn->tempsock[other] == CURL_SOCKET_BAD)
+          /* the last attempt failed and no other sockets remain open */
+          result = status;
+      }
+    }
+  }
+
+  if(result) {
+    /* no more addresses to try */
+    const char *hostname;
+    char buffer[STRERROR_LEN];
+
+    /* if the first address family runs out of addresses to try before
+       the happy eyeball timeout, go ahead and try the next family now */
+    if(conn->tempaddr[1] == NULL) {
+      result = trynextip(conn, sockindex, 1);
+      if(!result)
+        return result;
+    }
+
+    if(conn->bits.socksproxy)
+      hostname = conn->socks_proxy.host.name;
+    else if(conn->bits.httpproxy)
+      hostname = conn->http_proxy.host.name;
+    else if(conn->bits.conn_to_host)
+      hostname = conn->conn_to_host.name;
+    else
+      hostname = conn->host.name;
+
+    failf(data, "Failed to connect to %s port %ld: %s",
+          hostname, conn->port,
+          Curl_strerror(error, buffer, sizeof(buffer)));
+  }
+
+  return result;
+}
+
+static void tcpnodelay(struct connectdata *conn, curl_socket_t sockfd)
+{
+#if defined(TCP_NODELAY)
+#if !defined(CURL_DISABLE_VERBOSE_STRINGS)
+  struct Curl_easy *data = conn->data;
+#endif
+  curl_socklen_t onoff = (curl_socklen_t) 1;
+  int level = IPPROTO_TCP;
+  char buffer[STRERROR_LEN];
+
+#if defined(CURL_DISABLE_VERBOSE_STRINGS)
+  (void) conn;
+#endif
+
+  if(setsockopt(sockfd, level, TCP_NODELAY, (void *)&onoff,
+                sizeof(onoff)) < 0)
+    infof(data, "Could not set TCP_NODELAY: %s\n",
+          Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
+  else
+    infof(data, "TCP_NODELAY set\n");
+#else
+  (void)conn;
+  (void)sockfd;
+#endif
+}
+
+#ifdef SO_NOSIGPIPE
+/* The preferred method on Mac OS X (10.2 and later) to prevent SIGPIPEs when
+   sending data to a dead peer (instead of relying on the 4th argument to send
+   being MSG_NOSIGNAL). Possibly also existing and in use on other BSD
+   systems? */
+static void nosigpipe(struct connectdata *conn,
+                      curl_socket_t sockfd)
+{
+  struct Curl_easy *data = conn->data;
+  int onoff = 1;
+  if(setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&onoff,
+                sizeof(onoff)) < 0) {
+    char buffer[STRERROR_LEN];
+    infof(data, "Could not set SO_NOSIGPIPE: %s\n",
+          Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
+  }
+}
+#else
+#define nosigpipe(x,y) Curl_nop_stmt
+#endif
+
+#ifdef USE_WINSOCK
+/* When you run a program that uses the Windows Sockets API, you may
+   experience slow performance when you copy data to a TCP server.
+
+   https://support.microsoft.com/kb/823764
+
+   Work-around: Make the Socket Send Buffer Size Larger Than the Program Send
+   Buffer Size
+
+   The problem described in this knowledge-base is applied only to pre-Vista
+   Windows.  Following function trying to detect OS version and skips
+   SO_SNDBUF adjustment for Windows Vista and above.
+*/
+#define DETECT_OS_NONE 0
+#define DETECT_OS_PREVISTA 1
+#define DETECT_OS_VISTA_OR_LATER 2
+
+void Curl_sndbufset(curl_socket_t sockfd)
+{
+  int val = CURL_MAX_WRITE_SIZE + 32;
+  int curval = 0;
+  int curlen = sizeof(curval);
+
+  static int detectOsState = DETECT_OS_NONE;
+
+  if(detectOsState == DETECT_OS_NONE) {
+    if(Curl_verify_windows_version(6, 0, PLATFORM_WINNT,
+                                   VERSION_GREATER_THAN_EQUAL))
+      detectOsState = DETECT_OS_VISTA_OR_LATER;
+    else
+      detectOsState = DETECT_OS_PREVISTA;
+  }
+
+  if(detectOsState == DETECT_OS_VISTA_OR_LATER)
+    return;
+
+  if(getsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, (char *)&curval, &curlen) == 0)
+    if(curval > val)
+      return;
+
+  setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, (const char *)&val, sizeof(val));
+}
+#endif
+
+/*
+ * singleipconnect()
+ *
+ * Note that even on connect fail it returns CURLE_OK, but with 'sock' set to
+ * CURL_SOCKET_BAD. Other errors will however return proper errors.
+ *
+ * singleipconnect() connects to the given IP only, and it may return without
+ * having connected.
+ */
+static CURLcode singleipconnect(struct connectdata *conn,
+                                const Curl_addrinfo *ai,
+                                int sockindex)
+{
+  struct Curl_sockaddr_ex addr;
+  int rc = -1;
+  int error = 0;
+  bool isconnected = FALSE;
+  struct Curl_easy *data = conn->data;
+  curl_socket_t sockfd;
+  CURLcode result;
+  char ipaddress[MAX_IPADR_LEN];
+  long port;
+  bool is_tcp;
+#ifdef TCP_FASTOPEN_CONNECT
+  int optval = 1;
+#endif
+  char buffer[STRERROR_LEN];
+  curl_socket_t *sockp = &conn->tempsock[sockindex];
+  *sockp = CURL_SOCKET_BAD;
+
+  result = Curl_socket(conn, ai, &addr, &sockfd);
+  if(result)
+    /* Failed to create the socket, but still return OK since we signal the
+       lack of socket as well. This allows the parent function to keep looping
+       over alternative addresses/socket families etc. */
+    return CURLE_OK;
+
+  /* store remote address and port used in this connection attempt */
+  if(!Curl_addr2string((struct sockaddr*)&addr.sa_addr, addr.addrlen,
+                       ipaddress, &port)) {
+    /* malformed address or bug in inet_ntop, try next address */
+    failf(data, "sa_addr inet_ntop() failed with errno %d: %s",
+          errno, Curl_strerror(errno, buffer, sizeof(buffer)));
+    Curl_closesocket(conn, sockfd);
+    return CURLE_OK;
+  }
+  infof(data, "  Trying %s:%ld...\n", ipaddress, port);
+
+#ifdef ENABLE_IPV6
+  is_tcp = (addr.family == AF_INET || addr.family == AF_INET6) &&
+    addr.socktype == SOCK_STREAM;
+#else
+  is_tcp = (addr.family == AF_INET) && addr.socktype == SOCK_STREAM;
+#endif
+  if(is_tcp && data->set.tcp_nodelay)
+    tcpnodelay(conn, sockfd);
+
+  nosigpipe(conn, sockfd);
+
+  Curl_sndbufset(sockfd);
+
+  if(is_tcp && data->set.tcp_keepalive)
+    tcpkeepalive(data, sockfd);
+
+  if(data->set.fsockopt) {
+    /* activate callback for setting socket options */
+    Curl_set_in_callback(data, true);
+    error = data->set.fsockopt(data->set.sockopt_client,
+                               sockfd,
+                               CURLSOCKTYPE_IPCXN);
+    Curl_set_in_callback(data, false);
+
+    if(error == CURL_SOCKOPT_ALREADY_CONNECTED)
+      isconnected = TRUE;
+    else if(error) {
+      Curl_closesocket(conn, sockfd); /* close the socket and bail out */
+      return CURLE_ABORTED_BY_CALLBACK;
+    }
+  }
+
+  /* possibly bind the local end to an IP, interface or port */
+  if(addr.family == AF_INET
+#ifdef ENABLE_IPV6
+     || addr.family == AF_INET6
+#endif
+    ) {
+    result = bindlocal(conn, sockfd, addr.family,
+                       Curl_ipv6_scope((struct sockaddr*)&addr.sa_addr));
+    if(result) {
+      Curl_closesocket(conn, sockfd); /* close socket and bail out */
+      if(result == CURLE_UNSUPPORTED_PROTOCOL) {
+        /* The address family is not supported on this interface.
+           We can continue trying addresses */
+        return CURLE_COULDNT_CONNECT;
+      }
+      return result;
+    }
+  }
+
+  /* set socket non-blocking */
+  (void)curlx_nonblock(sockfd, TRUE);
+
+  conn->connecttime = Curl_now();
+  if(conn->num_addr > 1)
+    Curl_expire(data, conn->timeoutms_per_addr, EXPIRE_DNS_PER_NAME);
+
+  /* Connect TCP and QUIC sockets */
+  if(!isconnected && (conn->transport != TRNSPRT_UDP)) {
+    if(conn->bits.tcp_fastopen) {
+#if defined(CONNECT_DATA_IDEMPOTENT) /* Darwin */
+#  if defined(HAVE_BUILTIN_AVAILABLE)
+      /* while connectx function is available since macOS 10.11 / iOS 9,
+         it did not have the interface declared correctly until
+         Xcode 9 / macOS SDK 10.13 */
+      if(__builtin_available(macOS 10.11, iOS 9.0, tvOS 9.0, watchOS 2.0, *)) {
+        sa_endpoints_t endpoints;
+        endpoints.sae_srcif = 0;
+        endpoints.sae_srcaddr = NULL;
+        endpoints.sae_srcaddrlen = 0;
+        endpoints.sae_dstaddr = &addr.sa_addr;
+        endpoints.sae_dstaddrlen = addr.addrlen;
+
+        rc = connectx(sockfd, &endpoints, SAE_ASSOCID_ANY,
+                      CONNECT_RESUME_ON_READ_WRITE | CONNECT_DATA_IDEMPOTENT,
+                      NULL, 0, NULL, NULL);
+      }
+      else {
+        rc = connect(sockfd, &addr.sa_addr, addr.addrlen);
+      }
+#  else
+      rc = connect(sockfd, &addr.sa_addr, addr.addrlen);
+#  endif /* HAVE_BUILTIN_AVAILABLE */
+#elif defined(TCP_FASTOPEN_CONNECT) /* Linux >= 4.11 */
+      if(setsockopt(sockfd, IPPROTO_TCP, TCP_FASTOPEN_CONNECT,
+                    (void *)&optval, sizeof(optval)) < 0)
+        infof(data, "Failed to enable TCP Fast Open on fd %d\n", sockfd);
+      else
+        infof(data, "TCP_FASTOPEN_CONNECT set\n");
+
+      rc = connect(sockfd, &addr.sa_addr, addr.addrlen);
+#elif defined(MSG_FASTOPEN) /* old Linux */
+      if(conn->given->flags & PROTOPT_SSL)
+        rc = connect(sockfd, &addr.sa_addr, addr.addrlen);
+      else
+        rc = 0; /* Do nothing */
+#endif
+    }
+    else {
+      rc = connect(sockfd, &addr.sa_addr, addr.addrlen);
+    }
+
+    if(-1 == rc)
+      error = SOCKERRNO;
+#ifdef ENABLE_QUIC
+    else if(conn->transport == TRNSPRT_QUIC) {
+      /* pass in 'sockfd' separately since it hasn't been put into the
+         tempsock array at this point */
+      result = Curl_quic_connect(conn, sockfd, sockindex,
+                                 &addr.sa_addr, addr.addrlen);
+      if(result)
+        error = SOCKERRNO;
+    }
+#endif
+  }
+  else {
+    *sockp = sockfd;
+    return CURLE_OK;
+  }
+
+  if(-1 == rc) {
+    switch(error) {
+    case EINPROGRESS:
+    case EWOULDBLOCK:
+#if defined(EAGAIN)
+#if (EAGAIN) != (EWOULDBLOCK)
+      /* On some platforms EAGAIN and EWOULDBLOCK are the
+       * same value, and on others they are different, hence
+       * the odd #if
+       */
+    case EAGAIN:
+#endif
+#endif
+      result = CURLE_OK;
+      break;
+
+    default:
+      /* unknown error, fallthrough and try another address! */
+      infof(data, "Immediate connect fail for %s: %s\n",
+            ipaddress, Curl_strerror(error, buffer, sizeof(buffer)));
+      data->state.os_errno = error;
+
+      /* connect failed */
+      Curl_closesocket(conn, sockfd);
+      result = CURLE_COULDNT_CONNECT;
+    }
+  }
+
+  if(!result)
+    *sockp = sockfd;
+
+  return result;
+}
+
+/*
+ * TCP connect to the given host with timeout, proxy or remote doesn't matter.
+ * There might be more than one IP address to try out. Fill in the passed
+ * pointer with the connected socket.
+ */
+
+CURLcode Curl_connecthost(struct connectdata *conn,  /* context */
+                          const struct Curl_dns_entry *remotehost)
+{
+  struct Curl_easy *data = conn->data;
+  struct curltime before = Curl_now();
+  CURLcode result = CURLE_COULDNT_CONNECT;
+
+  timediff_t timeout_ms = Curl_timeleft(data, &before, TRUE);
+
+  if(timeout_ms < 0) {
+    /* a precaution, no need to continue if time already is up */
+    failf(data, "Connection time-out");
+    return CURLE_OPERATION_TIMEDOUT;
+  }
+
+  conn->num_addr = Curl_num_addresses(remotehost->addr);
+  conn->tempaddr[0] = remotehost->addr;
+  conn->tempaddr[1] = NULL;
+  conn->tempsock[0] = CURL_SOCKET_BAD;
+  conn->tempsock[1] = CURL_SOCKET_BAD;
+
+  /* Max time for the next connection attempt */
+  conn->timeoutms_per_addr =
+    conn->tempaddr[0]->ai_next == NULL ? timeout_ms : timeout_ms / 2;
+
+  /* start connecting to first IP */
+  while(conn->tempaddr[0]) {
+    result = singleipconnect(conn, conn->tempaddr[0], 0);
+    if(!result)
+      break;
+    conn->tempaddr[0] = conn->tempaddr[0]->ai_next;
+  }
+
+  if(conn->tempsock[0] == CURL_SOCKET_BAD) {
+    if(!result)
+      result = CURLE_COULDNT_CONNECT;
+    return result;
+  }
+
+  data->info.numconnects++; /* to track the number of connections made */
+  Curl_expire(conn->data, data->set.happy_eyeballs_timeout,
+              EXPIRE_HAPPY_EYEBALLS);
+
+  return CURLE_OK;
+}
+
+struct connfind {
+  struct connectdata *tofind;
+  bool found;
+};
+
+static int conn_is_conn(struct connectdata *conn, void *param)
+{
+  struct connfind *f = (struct connfind *)param;
+  if(conn == f->tofind) {
+    f->found = TRUE;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+ * Used to extract socket and connectdata struct for the most recent
+ * transfer on the given Curl_easy.
+ *
+ * The returned socket will be CURL_SOCKET_BAD in case of failure!
+ */
+curl_socket_t Curl_getconnectinfo(struct Curl_easy *data,
+                                  struct connectdata **connp)
+{
+  DEBUGASSERT(data);
+
+  /* this works for an easy handle:
+   * - that has been used for curl_easy_perform()
+   * - that is associated with a multi handle, and whose connection
+   *   was detached with CURLOPT_CONNECT_ONLY
+   */
+  if(data->state.lastconnect && (data->multi_easy || data->multi)) {
+    struct connectdata *c = data->state.lastconnect;
+    struct connfind find;
+    find.tofind = data->state.lastconnect;
+    find.found = FALSE;
+
+    Curl_conncache_foreach(data, data->multi_easy?
+                           &data->multi_easy->conn_cache:
+                           &data->multi->conn_cache, &find, conn_is_conn);
+
+    if(!find.found) {
+      data->state.lastconnect = NULL;
+      return CURL_SOCKET_BAD;
+    }
+
+    if(connp) {
+      /* only store this if the caller cares for it */
+      *connp = c;
+      c->data = data;
+    }
+    return c->sock[FIRSTSOCKET];
+  }
+  else
+    return CURL_SOCKET_BAD;
+}
+
+/*
+ * Check if a connection seems to be alive.
+ */
+bool Curl_connalive(struct connectdata *conn)
+{
+  /* First determine if ssl */
+  if(conn->ssl[FIRSTSOCKET].use) {
+    /* use the SSL context */
+    if(!Curl_ssl_check_cxn(conn))
+      return false;   /* FIN received */
+  }
+/* Minix 3.1 doesn't support any flags on recv; just assume socket is OK */
+#ifdef MSG_PEEK
+  else if(conn->sock[FIRSTSOCKET] == CURL_SOCKET_BAD)
+    return false;
+  else {
+    /* use the socket */
+    char buf;
+    if(recv((RECV_TYPE_ARG1)conn->sock[FIRSTSOCKET], (RECV_TYPE_ARG2)&buf,
+            (RECV_TYPE_ARG3)1, (RECV_TYPE_ARG4)MSG_PEEK) == 0) {
+      return false;   /* FIN received */
+    }
+  }
+#endif
+  return true;
+}
+
+/*
+ * Close a socket.
+ *
+ * 'conn' can be NULL, beware!
+ */
+int Curl_closesocket(struct connectdata *conn,
+                      curl_socket_t sock)
+{
+  if(conn && conn->fclosesocket) {
+    if((sock == conn->sock[SECONDARYSOCKET]) &&
+       conn->sock_accepted[SECONDARYSOCKET])
+      /* if this socket matches the second socket, and that was created with
+         accept, then we MUST NOT call the callback but clear the accepted
+         status */
+      conn->sock_accepted[SECONDARYSOCKET] = FALSE;
+    else {
+      int rc;
+      Curl_multi_closed(conn->data, sock);
+      Curl_set_in_callback(conn->data, true);
+      rc = conn->fclosesocket(conn->closesocket_client, sock);
+      Curl_set_in_callback(conn->data, false);
+      return rc;
+    }
+  }
+
+  if(conn)
+    /* tell the multi-socket code about this */
+    Curl_multi_closed(conn->data, sock);
+
+  sclose(sock);
+
+  return 0;
+}
+
+/*
+ * Create a socket based on info from 'conn' and 'ai'.
+ *
+ * 'addr' should be a pointer to the correct struct to get data back, or NULL.
+ * 'sockfd' must be a pointer to a socket descriptor.
+ *
+ * If the open socket callback is set, used that!
+ *
+ */
+CURLcode Curl_socket(struct connectdata *conn,
+                     const Curl_addrinfo *ai,
+                     struct Curl_sockaddr_ex *addr,
+                     curl_socket_t *sockfd)
+{
+  struct Curl_easy *data = conn->data;
+  struct Curl_sockaddr_ex dummy;
+
+  if(!addr)
+    /* if the caller doesn't want info back, use a local temp copy */
+    addr = &dummy;
+
+  /*
+   * The Curl_sockaddr_ex structure is basically libcurl's external API
+   * curl_sockaddr structure with enough space available to directly hold
+   * any protocol-specific address structures. The variable declared here
+   * will be used to pass / receive data to/from the fopensocket callback
+   * if this has been set, before that, it is initialized from parameters.
+   */
+
+  addr->family = ai->ai_family;
+  addr->socktype = (conn->transport == TRNSPRT_TCP) ? SOCK_STREAM : SOCK_DGRAM;
+  addr->protocol = conn->transport != TRNSPRT_TCP ? IPPROTO_UDP :
+    ai->ai_protocol;
+  addr->addrlen = ai->ai_addrlen;
+
+  if(addr->addrlen > sizeof(struct Curl_sockaddr_storage))
+     addr->addrlen = sizeof(struct Curl_sockaddr_storage);
+  memcpy(&addr->sa_addr, ai->ai_addr, addr->addrlen);
+
+  if(data->set.fopensocket) {
+   /*
+    * If the opensocket callback is set, all the destination address
+    * information is passed to the callback. Depending on this information the
+    * callback may opt to abort the connection, this is indicated returning
+    * CURL_SOCKET_BAD; otherwise it will return a not-connected socket. When
+    * the callback returns a valid socket the destination address information
+    * might have been changed and this 'new' address will actually be used
+    * here to connect.
+    */
+    Curl_set_in_callback(data, true);
+    *sockfd = data->set.fopensocket(data->set.opensocket_client,
+                                    CURLSOCKTYPE_IPCXN,
+                                    (struct curl_sockaddr *)addr);
+    Curl_set_in_callback(data, false);
+  }
+  else
+    /* opensocket callback not set, so simply create the socket now */
+    *sockfd = socket(addr->family, addr->socktype, addr->protocol);
+
+  if(*sockfd == CURL_SOCKET_BAD)
+    /* no socket, no connection */
+    return CURLE_COULDNT_CONNECT;
+
+#if defined(ENABLE_IPV6) && defined(HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID)
+  if(conn->scope_id && (addr->family == AF_INET6)) {
+    struct sockaddr_in6 * const sa6 = (void *)&addr->sa_addr;
+    sa6->sin6_scope_id = conn->scope_id;
+  }
+#endif
+
+  return CURLE_OK;
+
+}
+
+/*
+ * Curl_conncontrol() marks streams or connection for closure.
+ */
+void Curl_conncontrol(struct connectdata *conn,
+                      int ctrl /* see defines in header */
+#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
+                      , const char *reason
+#endif
+  )
+{
+  /* close if a connection, or a stream that isn't multiplexed */
+  bool closeit = (ctrl == CONNCTRL_CONNECTION) ||
+    ((ctrl == CONNCTRL_STREAM) && !(conn->handler->flags & PROTOPT_STREAM));
+  if((ctrl == CONNCTRL_STREAM) &&
+     (conn->handler->flags & PROTOPT_STREAM))
+    DEBUGF(infof(conn->data, "Kill stream: %s\n", reason));
+  else if((bit)closeit != conn->bits.close) {
+    DEBUGF(infof(conn->data, "Marked for [%s]: %s\n",
+                 closeit?"closure":"keep alive", reason));
+    conn->bits.close = closeit; /* the only place in the source code that
+                                   should assign this bit */
+  }
+}
+
+/* Data received can be cached at various levels, so check them all here. */
+bool Curl_conn_data_pending(struct connectdata *conn, int sockindex)
+{
+  int readable;
+
+  if(Curl_ssl_data_pending(conn, sockindex) ||
+     Curl_recv_has_postponed_data(conn, sockindex))
+    return true;
+
+  readable = SOCKET_READABLE(conn->sock[sockindex], 0);
+  return (readable > 0 && (readable & CURL_CSELECT_IN));
+}