Restoring authorship annotation for <shadchin@yandex-team.ru>. Commit 1 of 2.

1 files changed, 495 insertions, 495 deletions

diff --git a/contrib/libs/c-ares/ares__sortaddrinfo.c b/contrib/libs/c-ares/ares__sortaddrinfo.c
index c0e2ea1528..b740860a6a 100644
--- a/contrib/libs/c-ares/ares__sortaddrinfo.c
+++ b/contrib/libs/c-ares/ares__sortaddrinfo.c
@@ -1,495 +1,495 @@
-/*
- * Original file name getaddrinfo.c
- * Lifted from the 'Android Bionic' project with the BSD license.
- */
-
-/*
- * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
- * Copyright (C) 2018 The Android Open Source Project
- * Copyright (C) 2019 by Andrew Selivanov
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the project nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include "ares_setup.h"
-
-#ifdef HAVE_NETINET_IN_H
-#  include <netinet/in.h>
-#endif
-#ifdef HAVE_NETDB_H
-#  include <netdb.h>
-#endif
-#ifdef HAVE_STRINGS_H
-#  include <strings.h>
-#endif
-
-#include <assert.h>
-#include <limits.h>
-
-#include "ares.h"
-#include "ares_private.h"
-
-struct addrinfo_sort_elem
-{
-  struct ares_addrinfo_node *ai;
-  int has_src_addr;
-  ares_sockaddr src_addr;
-  int original_order;
-};
-
-#define ARES_IPV6_ADDR_MC_SCOPE(a) ((a)->s6_addr[1] & 0x0f)
-
-#define ARES_IPV6_ADDR_SCOPE_NODELOCAL       0x01
-#define ARES_IPV6_ADDR_SCOPE_INTFACELOCAL    0x01
-#define ARES_IPV6_ADDR_SCOPE_LINKLOCAL       0x02
-#define ARES_IPV6_ADDR_SCOPE_SITELOCAL       0x05
-#define ARES_IPV6_ADDR_SCOPE_ORGLOCAL        0x08
-#define ARES_IPV6_ADDR_SCOPE_GLOBAL          0x0e
-
-#define ARES_IN_LOOPBACK(a) ((((long int)(a)) & 0xff000000) == 0x7f000000)
-
-/* RFC 4193. */
-#define ARES_IN6_IS_ADDR_ULA(a) (((a)->s6_addr[0] & 0xfe) == 0xfc)
-
-/* These macros are modelled after the ones in <netinet/in6.h>. */
-/* RFC 4380, section 2.6 */
-#define ARES_IN6_IS_ADDR_TEREDO(a)    \
-        ((*(const unsigned int *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
-/* RFC 3056, section 2. */
-#define ARES_IN6_IS_ADDR_6TO4(a)      \
-        (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
-/* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
-#define ARES_IN6_IS_ADDR_6BONE(a)      \
-        (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
-
-
-static int get_scope(const struct sockaddr *addr)
-{
-  if (addr->sa_family == AF_INET6)
-    {
-      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr);
-      if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr))
-        {
-          return ARES_IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
-        }
-      else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
-               IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr))
-        {
-          /*
-           * RFC 4291 section 2.5.3 says loopback is to be treated as having
-           * link-local scope.
-           */
-          return ARES_IPV6_ADDR_SCOPE_LINKLOCAL;
-        }
-      else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr))
-        {
-          return ARES_IPV6_ADDR_SCOPE_SITELOCAL;
-        }
-      else
-        {
-          return ARES_IPV6_ADDR_SCOPE_GLOBAL;
-        }
-    }
-  else if (addr->sa_family == AF_INET)
-    {
-      const struct sockaddr_in *addr4 = CARES_INADDR_CAST(const struct sockaddr_in *, addr);
-      unsigned long int na = ntohl(addr4->sin_addr.s_addr);
-      if (ARES_IN_LOOPBACK(na) || /* 127.0.0.0/8 */
-          (na & 0xffff0000) == 0xa9fe0000) /* 169.254.0.0/16 */
-        {
-          return ARES_IPV6_ADDR_SCOPE_LINKLOCAL;
-        }
-      else
-        {
-          /*
-           * RFC 6724 section 3.2. Other IPv4 addresses, including private
-           * addresses and shared addresses (100.64.0.0/10), are assigned global
-           * scope.
-           */
-          return ARES_IPV6_ADDR_SCOPE_GLOBAL;
-        }
-    }
-  else
-    {
-      /*
-       * This should never happen.
-       * Return a scope with low priority as a last resort.
-       */
-      return ARES_IPV6_ADDR_SCOPE_NODELOCAL;
-    }
-}
-
-static int get_label(const struct sockaddr *addr)
-{
-  if (addr->sa_family == AF_INET)
-    {
-      return 4;
-    }
-  else if (addr->sa_family == AF_INET6)
-    {
-      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr);
-      if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr))
-        {
-          return 0;
-        }
-      else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr))
-        {
-          return 4;
-        }
-      else if (ARES_IN6_IS_ADDR_6TO4(&addr6->sin6_addr))
-        {
-          return 2;
-        }
-      else if (ARES_IN6_IS_ADDR_TEREDO(&addr6->sin6_addr))
-        {
-          return 5;
-        }
-      else if (ARES_IN6_IS_ADDR_ULA(&addr6->sin6_addr))
-        {
-          return 13;
-        }
-      else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr))
-        {
-          return 3;
-        }
-      else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr))
-        {
-          return 11;
-        }
-      else if (ARES_IN6_IS_ADDR_6BONE(&addr6->sin6_addr))
-        {
-          return 12;
-        }
-      else
-        {
-          /* All other IPv6 addresses, including global unicast addresses. */
-          return 1;
-        }
-    }
-  else
-    {
-      /*
-       * This should never happen.
-       * Return a semi-random label as a last resort.
-       */
-      return 1;
-    }
-}
-
-/*
- * Get the precedence for a given IPv4/IPv6 address.
- * RFC 6724, section 2.1.
- */
-static int get_precedence(const struct sockaddr *addr)
-{
-  if (addr->sa_family == AF_INET)
-    {
-      return 35;
-    }
-  else if (addr->sa_family == AF_INET6)
-    {
-      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr);
-      if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr))
-        {
-          return 50;
-        }
-      else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr))
-        {
-          return 35;
-        }
-      else if (ARES_IN6_IS_ADDR_6TO4(&addr6->sin6_addr))
-        {
-          return 30;
-        }
-      else if (ARES_IN6_IS_ADDR_TEREDO(&addr6->sin6_addr))
-        {
-          return 5;
-        }
-      else if (ARES_IN6_IS_ADDR_ULA(&addr6->sin6_addr))
-        {
-          return 3;
-        }
-      else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
-               IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
-               ARES_IN6_IS_ADDR_6BONE(&addr6->sin6_addr))
-        {
-          return 1;
-        }
-      else
-        {
-          /* All other IPv6 addresses, including global unicast addresses. */
-          return 40;
-        }
-    }
-  else
-    {
-      return 1;
-    }
-}
-
-/*
- * Find number of matching initial bits between the two addresses a1 and a2.
- */
-static int common_prefix_len(const struct in6_addr *a1,
-                             const struct in6_addr *a2)
-{
-  const char *p1 = (const char *)a1;
-  const char *p2 = (const char *)a2;
-  unsigned i;
-  for (i = 0; i < sizeof(*a1); ++i)
-    {
-      int x, j;
-      if (p1[i] == p2[i])
-        {
-          continue;
-        }
-      x = p1[i] ^ p2[i];
-      for (j = 0; j < CHAR_BIT; ++j)
-        {
-          if (x & (1 << (CHAR_BIT - 1)))
-            {
-              return i * CHAR_BIT + j;
-            }
-          x <<= 1;
-        }
-    }
-  return sizeof(*a1) * CHAR_BIT;
-}
-
-/*
- * Compare two source/destination address pairs.
- * RFC 6724, section 6.
- */
-static int rfc6724_compare(const void *ptr1, const void *ptr2)
-{
-  const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
-  const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
-  int scope_src1, scope_dst1, scope_match1;
-  int scope_src2, scope_dst2, scope_match2;
-  int label_src1, label_dst1, label_match1;
-  int label_src2, label_dst2, label_match2;
-  int precedence1, precedence2;
-  int prefixlen1, prefixlen2;
-
-  /* Rule 1: Avoid unusable destinations. */
-  if (a1->has_src_addr != a2->has_src_addr)
-    {
-      return a2->has_src_addr - a1->has_src_addr;
-    }
-
-  /* Rule 2: Prefer matching scope. */
-  scope_src1 = get_scope(&a1->src_addr.sa);
-  scope_dst1 = get_scope(a1->ai->ai_addr);
-  scope_match1 = (scope_src1 == scope_dst1);
-
-  scope_src2 = get_scope(&a2->src_addr.sa);
-  scope_dst2 = get_scope(a2->ai->ai_addr);
-  scope_match2 = (scope_src2 == scope_dst2);
-
-  if (scope_match1 != scope_match2)
-    {
-      return scope_match2 - scope_match1;
-    }
-
-  /* Rule 3: Avoid deprecated addresses.  */
-
-  /* Rule 4: Prefer home addresses.  */
-
-  /* Rule 5: Prefer matching label. */
-  label_src1 = get_label(&a1->src_addr.sa);
-  label_dst1 = get_label(a1->ai->ai_addr);
-  label_match1 = (label_src1 == label_dst1);
-
-  label_src2 = get_label(&a2->src_addr.sa);
-  label_dst2 = get_label(a2->ai->ai_addr);
-  label_match2 = (label_src2 == label_dst2);
-
-  if (label_match1 != label_match2)
-    {
-      return label_match2 - label_match1;
-    }
-
-  /* Rule 6: Prefer higher precedence. */
-  precedence1 = get_precedence(a1->ai->ai_addr);
-  precedence2 = get_precedence(a2->ai->ai_addr);
-  if (precedence1 != precedence2)
-    {
-      return precedence2 - precedence1;
-    }
-
-  /* Rule 7: Prefer native transport.  */
-
-  /* Rule 8: Prefer smaller scope. */
-  if (scope_dst1 != scope_dst2)
-    {
-      return scope_dst1 - scope_dst2;
-    }
-
-  /* Rule 9: Use longest matching prefix. */
-  if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
-      a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6)
-    {
-      const struct sockaddr_in6 *a1_src = &a1->src_addr.sa6;
-      const struct sockaddr_in6 *a1_dst =
-          CARES_INADDR_CAST(const struct sockaddr_in6 *, a1->ai->ai_addr);
-      const struct sockaddr_in6 *a2_src = &a2->src_addr.sa6;
-      const struct sockaddr_in6 *a2_dst =
-          CARES_INADDR_CAST(const struct sockaddr_in6 *, a2->ai->ai_addr);
-      prefixlen1 = common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
-      prefixlen2 = common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
-      if (prefixlen1 != prefixlen2)
-        {
-          return prefixlen2 - prefixlen1;
-        }
-    }
-
-  /*
-   * Rule 10: Leave the order unchanged.
-   * We need this since qsort() is not necessarily stable.
-   */
-  return a1->original_order - a2->original_order;
-}
-
-/*
- * Find the source address that will be used if trying to connect to the given
- * address.
- *
- * Returns 1 if a source address was found, 0 if the address is unreachable,
- * and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are
- * undefined.
- */
-static int find_src_addr(ares_channel channel,
-                         const struct sockaddr *addr,
-                         struct sockaddr *src_addr)
-{
-  int sock;
-  int ret;
-  ares_socklen_t len;
-
-  switch (addr->sa_family)
-    {
-    case AF_INET:
-      len = sizeof(struct sockaddr_in);
-      break;
-    case AF_INET6:
-      len = sizeof(struct sockaddr_in6);
-      break;
-    default:
-      /* No known usable source address for non-INET families. */
-      return 0;
-    }
-
-  sock = ares__open_socket(channel, addr->sa_family, SOCK_DGRAM, IPPROTO_UDP);
-  if (sock == -1)
-    {
-      if (errno == EAFNOSUPPORT)
-        {
-          return 0;
-        }
-      else
-        {
-          return -1;
-        }
-    }
-
-  do
-    {
-      ret = ares__connect_socket(channel, sock, addr, len);
-    }
-  while (ret == -1 && errno == EINTR);
-
-  if (ret == -1)
-    {
-      ares__close_socket(channel, sock);
-      return 0;
-    }
-
-  if (getsockname(sock, src_addr, &len) == -1)
-    {
-      ares__close_socket(channel, sock);
-      return -1;
-    }
-  ares__close_socket(channel, sock);
-  return 1;
-}
-
-/*
- * Sort the linked list starting at sentinel->ai_next in RFC6724 order.
- * Will leave the list unchanged if an error occurs.
- */
-int ares__sortaddrinfo(ares_channel channel, struct ares_addrinfo_node *list_sentinel)
-{
-  struct ares_addrinfo_node *cur;
-  int nelem = 0, i;
-  int has_src_addr;
-  struct addrinfo_sort_elem *elems;
-
-  cur = list_sentinel->ai_next;
-  while (cur)
-    {
-      ++nelem;
-      cur = cur->ai_next;
-    }
-  elems = (struct addrinfo_sort_elem *)ares_malloc(
-      nelem * sizeof(struct addrinfo_sort_elem));
-  if (!elems)
-    {
-      return ARES_ENOMEM;
-    }
-
-  /*
-   * Convert the linked list to an array that also contains the candidate
-   * source address for each destination address.
-   */
-  for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next)
-    {
-      assert(cur != NULL);
-      elems[i].ai = cur;
-      elems[i].original_order = i;
-      has_src_addr = find_src_addr(channel, cur->ai_addr, &elems[i].src_addr.sa);
-      if (has_src_addr == -1)
-        {
-          ares_free(elems);
-          return ARES_ENOTFOUND;
-        }
-      elems[i].has_src_addr = has_src_addr;
-    }
-
-  /* Sort the addresses, and rearrange the linked list so it matches the sorted
-   * order. */
-  qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem),
-        rfc6724_compare);
-
-  list_sentinel->ai_next = elems[0].ai;
-  for (i = 0; i < nelem - 1; ++i)
-    {
-      elems[i].ai->ai_next = elems[i + 1].ai;
-    }
-  elems[nelem - 1].ai->ai_next = NULL;
-
-  ares_free(elems);
-  return ARES_SUCCESS;
-}
+/* 
+ * Original file name getaddrinfo.c 
+ * Lifted from the 'Android Bionic' project with the BSD license. 
+ */ 
+ 
+/* 
+ * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 
+ * Copyright (C) 2018 The Android Open Source Project 
+ * Copyright (C) 2019 by Andrew Selivanov 
+ * All rights reserved. 
+ * 
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of the project nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ */ 
+ 
+#include "ares_setup.h" 
+ 
+#ifdef HAVE_NETINET_IN_H 
+#  include <netinet/in.h> 
+#endif 
+#ifdef HAVE_NETDB_H 
+#  include <netdb.h> 
+#endif 
+#ifdef HAVE_STRINGS_H 
+#  include <strings.h> 
+#endif 
+ 
+#include <assert.h> 
+#include <limits.h> 
+ 
+#include "ares.h" 
+#include "ares_private.h" 
+ 
+struct addrinfo_sort_elem 
+{ 
+  struct ares_addrinfo_node *ai; 
+  int has_src_addr; 
+  ares_sockaddr src_addr; 
+  int original_order; 
+}; 
+ 
+#define ARES_IPV6_ADDR_MC_SCOPE(a) ((a)->s6_addr[1] & 0x0f) 
+ 
+#define ARES_IPV6_ADDR_SCOPE_NODELOCAL       0x01 
+#define ARES_IPV6_ADDR_SCOPE_INTFACELOCAL    0x01 
+#define ARES_IPV6_ADDR_SCOPE_LINKLOCAL       0x02 
+#define ARES_IPV6_ADDR_SCOPE_SITELOCAL       0x05 
+#define ARES_IPV6_ADDR_SCOPE_ORGLOCAL        0x08 
+#define ARES_IPV6_ADDR_SCOPE_GLOBAL          0x0e 
+ 
+#define ARES_IN_LOOPBACK(a) ((((long int)(a)) & 0xff000000) == 0x7f000000) 
+ 
+/* RFC 4193. */ 
+#define ARES_IN6_IS_ADDR_ULA(a) (((a)->s6_addr[0] & 0xfe) == 0xfc) 
+ 
+/* These macros are modelled after the ones in <netinet/in6.h>. */ 
+/* RFC 4380, section 2.6 */ 
+#define ARES_IN6_IS_ADDR_TEREDO(a)    \ 
+        ((*(const unsigned int *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000))) 
+/* RFC 3056, section 2. */ 
+#define ARES_IN6_IS_ADDR_6TO4(a)      \ 
+        (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02)) 
+/* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */ 
+#define ARES_IN6_IS_ADDR_6BONE(a)      \ 
+        (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe)) 
+ 
+ 
+static int get_scope(const struct sockaddr *addr) 
+{ 
+  if (addr->sa_family == AF_INET6) 
+    { 
+      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr); 
+      if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) 
+        { 
+          return ARES_IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr); 
+        } 
+      else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) || 
+               IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) 
+        { 
+          /* 
+           * RFC 4291 section 2.5.3 says loopback is to be treated as having 
+           * link-local scope. 
+           */ 
+          return ARES_IPV6_ADDR_SCOPE_LINKLOCAL; 
+        } 
+      else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) 
+        { 
+          return ARES_IPV6_ADDR_SCOPE_SITELOCAL; 
+        } 
+      else 
+        { 
+          return ARES_IPV6_ADDR_SCOPE_GLOBAL; 
+        } 
+    } 
+  else if (addr->sa_family == AF_INET) 
+    { 
+      const struct sockaddr_in *addr4 = CARES_INADDR_CAST(const struct sockaddr_in *, addr); 
+      unsigned long int na = ntohl(addr4->sin_addr.s_addr); 
+      if (ARES_IN_LOOPBACK(na) || /* 127.0.0.0/8 */ 
+          (na & 0xffff0000) == 0xa9fe0000) /* 169.254.0.0/16 */ 
+        { 
+          return ARES_IPV6_ADDR_SCOPE_LINKLOCAL; 
+        } 
+      else 
+        { 
+          /* 
+           * RFC 6724 section 3.2. Other IPv4 addresses, including private 
+           * addresses and shared addresses (100.64.0.0/10), are assigned global 
+           * scope. 
+           */ 
+          return ARES_IPV6_ADDR_SCOPE_GLOBAL; 
+        } 
+    } 
+  else 
+    { 
+      /* 
+       * This should never happen. 
+       * Return a scope with low priority as a last resort. 
+       */ 
+      return ARES_IPV6_ADDR_SCOPE_NODELOCAL; 
+    } 
+} 
+ 
+static int get_label(const struct sockaddr *addr) 
+{ 
+  if (addr->sa_family == AF_INET) 
+    { 
+      return 4; 
+    } 
+  else if (addr->sa_family == AF_INET6) 
+    { 
+      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr); 
+      if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) 
+        { 
+          return 0; 
+        } 
+      else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) 
+        { 
+          return 4; 
+        } 
+      else if (ARES_IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) 
+        { 
+          return 2; 
+        } 
+      else if (ARES_IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) 
+        { 
+          return 5; 
+        } 
+      else if (ARES_IN6_IS_ADDR_ULA(&addr6->sin6_addr)) 
+        { 
+          return 13; 
+        } 
+      else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) 
+        { 
+          return 3; 
+        } 
+      else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) 
+        { 
+          return 11; 
+        } 
+      else if (ARES_IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) 
+        { 
+          return 12; 
+        } 
+      else 
+        { 
+          /* All other IPv6 addresses, including global unicast addresses. */ 
+          return 1; 
+        } 
+    } 
+  else 
+    { 
+      /* 
+       * This should never happen. 
+       * Return a semi-random label as a last resort. 
+       */ 
+      return 1; 
+    } 
+} 
+ 
+/* 
+ * Get the precedence for a given IPv4/IPv6 address. 
+ * RFC 6724, section 2.1. 
+ */ 
+static int get_precedence(const struct sockaddr *addr) 
+{ 
+  if (addr->sa_family == AF_INET) 
+    { 
+      return 35; 
+    } 
+  else if (addr->sa_family == AF_INET6) 
+    { 
+      const struct sockaddr_in6 *addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, addr); 
+      if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) 
+        { 
+          return 50; 
+        } 
+      else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) 
+        { 
+          return 35; 
+        } 
+      else if (ARES_IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) 
+        { 
+          return 30; 
+        } 
+      else if (ARES_IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) 
+        { 
+          return 5; 
+        } 
+      else if (ARES_IN6_IS_ADDR_ULA(&addr6->sin6_addr)) 
+        { 
+          return 3; 
+        } 
+      else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) || 
+               IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) || 
+               ARES_IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) 
+        { 
+          return 1; 
+        } 
+      else 
+        { 
+          /* All other IPv6 addresses, including global unicast addresses. */ 
+          return 40; 
+        } 
+    } 
+  else 
+    { 
+      return 1; 
+    } 
+} 
+ 
+/* 
+ * Find number of matching initial bits between the two addresses a1 and a2. 
+ */ 
+static int common_prefix_len(const struct in6_addr *a1, 
+                             const struct in6_addr *a2) 
+{ 
+  const char *p1 = (const char *)a1; 
+  const char *p2 = (const char *)a2; 
+  unsigned i; 
+  for (i = 0; i < sizeof(*a1); ++i) 
+    { 
+      int x, j; 
+      if (p1[i] == p2[i]) 
+        { 
+          continue; 
+        } 
+      x = p1[i] ^ p2[i]; 
+      for (j = 0; j < CHAR_BIT; ++j) 
+        { 
+          if (x & (1 << (CHAR_BIT - 1))) 
+            { 
+              return i * CHAR_BIT + j; 
+            } 
+          x <<= 1; 
+        } 
+    } 
+  return sizeof(*a1) * CHAR_BIT; 
+} 
+ 
+/* 
+ * Compare two source/destination address pairs. 
+ * RFC 6724, section 6. 
+ */ 
+static int rfc6724_compare(const void *ptr1, const void *ptr2) 
+{ 
+  const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1; 
+  const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2; 
+  int scope_src1, scope_dst1, scope_match1; 
+  int scope_src2, scope_dst2, scope_match2; 
+  int label_src1, label_dst1, label_match1; 
+  int label_src2, label_dst2, label_match2; 
+  int precedence1, precedence2; 
+  int prefixlen1, prefixlen2; 
+ 
+  /* Rule 1: Avoid unusable destinations. */ 
+  if (a1->has_src_addr != a2->has_src_addr) 
+    { 
+      return a2->has_src_addr - a1->has_src_addr; 
+    } 
+ 
+  /* Rule 2: Prefer matching scope. */ 
+  scope_src1 = get_scope(&a1->src_addr.sa); 
+  scope_dst1 = get_scope(a1->ai->ai_addr); 
+  scope_match1 = (scope_src1 == scope_dst1); 
+ 
+  scope_src2 = get_scope(&a2->src_addr.sa); 
+  scope_dst2 = get_scope(a2->ai->ai_addr); 
+  scope_match2 = (scope_src2 == scope_dst2); 
+ 
+  if (scope_match1 != scope_match2) 
+    { 
+      return scope_match2 - scope_match1; 
+    } 
+ 
+  /* Rule 3: Avoid deprecated addresses.  */ 
+ 
+  /* Rule 4: Prefer home addresses.  */ 
+ 
+  /* Rule 5: Prefer matching label. */ 
+  label_src1 = get_label(&a1->src_addr.sa); 
+  label_dst1 = get_label(a1->ai->ai_addr); 
+  label_match1 = (label_src1 == label_dst1); 
+ 
+  label_src2 = get_label(&a2->src_addr.sa); 
+  label_dst2 = get_label(a2->ai->ai_addr); 
+  label_match2 = (label_src2 == label_dst2); 
+ 
+  if (label_match1 != label_match2) 
+    { 
+      return label_match2 - label_match1; 
+    } 
+ 
+  /* Rule 6: Prefer higher precedence. */ 
+  precedence1 = get_precedence(a1->ai->ai_addr); 
+  precedence2 = get_precedence(a2->ai->ai_addr); 
+  if (precedence1 != precedence2) 
+    { 
+      return precedence2 - precedence1; 
+    } 
+ 
+  /* Rule 7: Prefer native transport.  */ 
+ 
+  /* Rule 8: Prefer smaller scope. */ 
+  if (scope_dst1 != scope_dst2) 
+    { 
+      return scope_dst1 - scope_dst2; 
+    } 
+ 
+  /* Rule 9: Use longest matching prefix. */ 
+  if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 && 
+      a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) 
+    { 
+      const struct sockaddr_in6 *a1_src = &a1->src_addr.sa6; 
+      const struct sockaddr_in6 *a1_dst = 
+          CARES_INADDR_CAST(const struct sockaddr_in6 *, a1->ai->ai_addr); 
+      const struct sockaddr_in6 *a2_src = &a2->src_addr.sa6; 
+      const struct sockaddr_in6 *a2_dst = 
+          CARES_INADDR_CAST(const struct sockaddr_in6 *, a2->ai->ai_addr); 
+      prefixlen1 = common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr); 
+      prefixlen2 = common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr); 
+      if (prefixlen1 != prefixlen2) 
+        { 
+          return prefixlen2 - prefixlen1; 
+        } 
+    } 
+ 
+  /* 
+   * Rule 10: Leave the order unchanged. 
+   * We need this since qsort() is not necessarily stable. 
+   */ 
+  return a1->original_order - a2->original_order; 
+} 
+ 
+/* 
+ * Find the source address that will be used if trying to connect to the given 
+ * address. 
+ * 
+ * Returns 1 if a source address was found, 0 if the address is unreachable, 
+ * and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are 
+ * undefined. 
+ */ 
+static int find_src_addr(ares_channel channel, 
+                         const struct sockaddr *addr, 
+                         struct sockaddr *src_addr) 
+{ 
+  int sock; 
+  int ret; 
+  ares_socklen_t len; 
+ 
+  switch (addr->sa_family) 
+    { 
+    case AF_INET: 
+      len = sizeof(struct sockaddr_in); 
+      break; 
+    case AF_INET6: 
+      len = sizeof(struct sockaddr_in6); 
+      break; 
+    default: 
+      /* No known usable source address for non-INET families. */ 
+      return 0; 
+    } 
+ 
+  sock = ares__open_socket(channel, addr->sa_family, SOCK_DGRAM, IPPROTO_UDP); 
+  if (sock == -1) 
+    { 
+      if (errno == EAFNOSUPPORT) 
+        { 
+          return 0; 
+        } 
+      else 
+        { 
+          return -1; 
+        } 
+    } 
+ 
+  do 
+    { 
+      ret = ares__connect_socket(channel, sock, addr, len); 
+    } 
+  while (ret == -1 && errno == EINTR); 
+ 
+  if (ret == -1) 
+    { 
+      ares__close_socket(channel, sock); 
+      return 0; 
+    } 
+ 
+  if (getsockname(sock, src_addr, &len) == -1) 
+    { 
+      ares__close_socket(channel, sock); 
+      return -1; 
+    } 
+  ares__close_socket(channel, sock); 
+  return 1; 
+} 
+ 
+/* 
+ * Sort the linked list starting at sentinel->ai_next in RFC6724 order. 
+ * Will leave the list unchanged if an error occurs. 
+ */ 
+int ares__sortaddrinfo(ares_channel channel, struct ares_addrinfo_node *list_sentinel) 
+{ 
+  struct ares_addrinfo_node *cur; 
+  int nelem = 0, i; 
+  int has_src_addr; 
+  struct addrinfo_sort_elem *elems; 
+ 
+  cur = list_sentinel->ai_next; 
+  while (cur) 
+    { 
+      ++nelem; 
+      cur = cur->ai_next; 
+    } 
+  elems = (struct addrinfo_sort_elem *)ares_malloc( 
+      nelem * sizeof(struct addrinfo_sort_elem)); 
+  if (!elems) 
+    { 
+      return ARES_ENOMEM; 
+    } 
+ 
+  /* 
+   * Convert the linked list to an array that also contains the candidate 
+   * source address for each destination address. 
+   */ 
+  for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) 
+    { 
+      assert(cur != NULL); 
+      elems[i].ai = cur; 
+      elems[i].original_order = i; 
+      has_src_addr = find_src_addr(channel, cur->ai_addr, &elems[i].src_addr.sa); 
+      if (has_src_addr == -1) 
+        { 
+          ares_free(elems); 
+          return ARES_ENOTFOUND; 
+        } 
+      elems[i].has_src_addr = has_src_addr; 
+    } 
+ 
+  /* Sort the addresses, and rearrange the linked list so it matches the sorted 
+   * order. */ 
+  qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), 
+        rfc6724_compare); 
+ 
+  list_sentinel->ai_next = elems[0].ai; 
+  for (i = 0; i < nelem - 1; ++i) 
+    { 
+      elems[i].ai->ai_next = elems[i + 1].ai; 
+    } 
+  elems[nelem - 1].ai->ai_next = NULL; 
+ 
+  ares_free(elems); 
+  return ARES_SUCCESS; 
+}