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Diffstat (limited to 'src/third_party/cares/dist/src/lib/ares__sortaddrinfo.c')
-rw-r--r--src/third_party/cares/dist/src/lib/ares__sortaddrinfo.c499
1 files changed, 499 insertions, 0 deletions
diff --git a/src/third_party/cares/dist/src/lib/ares__sortaddrinfo.c b/src/third_party/cares/dist/src/lib/ares__sortaddrinfo.c
new file mode 100644
index 00000000000..6e56cc90230
--- /dev/null
+++ b/src/third_party/cares/dist/src/lib/ares__sortaddrinfo.c
@@ -0,0 +1,499 @@
+/*
+ * 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)
+{
+ ares_socket_t 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 == ARES_SOCKET_BAD)
+ {
+ 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) != 0)
+ {
+ 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;
+ }
+
+ if (!nelem)
+ return ARES_ENODATA;
+
+ 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;
+}
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