mirror of https://github.com/c-ares/c-ares.git
RFC6761: special case "localhost" (#430)
As per RFC6761 Section 6.3, "localhost" lookups need to be special cased to return loopback addresses, and not forward queries to recursive dns servers. We first look up via files (/etc/hosts or equivalent), and if that fails, we then attempt a system-specific address enumeration for loopback addresses (currently Windows-only), and finally fallback to ::1 and 127.0.0.1. Fix By: Brad House (@bradh352) Fixes Bug: #399pull/431/head
Brad House
3 years ago
committed by
GitHub
parent
c642b9fbb1
commit
29c4ecdc16
11 changed files with 270 additions and 12 deletions
@ -0,0 +1,236 @@ |
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/* Copyright (C) 2019 by Andrew Selivanov
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* |
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* Permission to use, copy, modify, and distribute this |
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* software and its documentation for any purpose and without |
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* fee is hereby granted, provided that the above copyright |
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* notice appear in all copies and that both that copyright |
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* notice and this permission notice appear in supporting |
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* documentation, and that the name of M.I.T. not be used in |
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* advertising or publicity pertaining to distribution of the |
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* software without specific, written prior permission. |
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* M.I.T. makes no representations about the suitability of |
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* this software for any purpose. It is provided "as is" |
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* without express or implied warranty. |
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*/ |
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#include "ares_setup.h" |
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#ifdef HAVE_NETINET_IN_H |
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# include <netinet/in.h> |
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#endif |
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#ifdef HAVE_NETDB_H |
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# include <netdb.h> |
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#endif |
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#ifdef HAVE_ARPA_INET_H |
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# include <arpa/inet.h> |
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#endif |
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#if defined(_WIN32) && defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0600 |
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#include <ws2ipdef.h> |
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#include <iphlpapi.h> |
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#endif |
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#include "ares.h" |
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#include "ares_inet_net_pton.h" |
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#include "ares_nowarn.h" |
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#include "ares_private.h" |
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static int ares_append_ai_node(int aftype, |
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unsigned short port, |
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const void *adata, |
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struct ares_addrinfo_node **nodes) |
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{ |
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struct ares_addrinfo_node *node; |
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node = ares__append_addrinfo_node(nodes); |
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if (!node) |
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{ |
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return ARES_ENOMEM; |
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} |
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memset(node, 0, sizeof(*node)); |
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if (aftype == AF_INET) |
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{ |
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struct sockaddr_in *sin = ares_malloc(sizeof(*sin)); |
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if (!sin) |
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{ |
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return ARES_ENOMEM; |
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} |
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memset(sin, 0, sizeof(*sin)); |
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memcpy(&sin->sin_addr.s_addr, adata, sizeof(struct in_addr)); |
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sin->sin_family = AF_INET; |
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sin->sin_port = htons(port); |
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node->ai_addr = (struct sockaddr *)sin; |
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node->ai_family = AF_INET; |
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node->ai_addrlen = sizeof(struct sockaddr_in); |
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node->ai_addr = (struct sockaddr *)sin; |
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} |
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if (aftype == AF_INET6) |
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{ |
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struct sockaddr_in6 *sin6 = ares_malloc(sizeof(*sin6)); |
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if (!sin6) |
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{ |
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return ARES_ENOMEM; |
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} |
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memset(sin6, 0, sizeof(*sin6)); |
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memcpy(&sin6->sin6_addr.s6_addr, adata, sizeof(struct ares_in6_addr)); |
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sin6->sin6_family = AF_INET6; |
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sin6->sin6_port = htons(port); |
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node->ai_addr = (struct sockaddr *)sin6; |
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node->ai_family = AF_INET6; |
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node->ai_addrlen = sizeof(struct ares_in6_addr); |
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node->ai_addr = (struct sockaddr *)sin6; |
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} |
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return ARES_SUCCESS; |
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} |
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static int ares__default_loopback_addrs(int aftype, |
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unsigned short port, |
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struct ares_addrinfo_node **nodes) |
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{ |
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int status = ARES_SUCCESS; |
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if (aftype == AF_UNSPEC || aftype == AF_INET6) |
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{ |
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struct ares_in6_addr addr6; |
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ares_inet_pton(AF_INET6, "::1", &addr6); |
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status = ares_append_ai_node(AF_INET6, port, &addr6, nodes); |
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if (status != ARES_SUCCESS) |
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{ |
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return status; |
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} |
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} |
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if (aftype == AF_UNSPEC || aftype == AF_INET) |
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{ |
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struct in_addr addr4; |
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ares_inet_pton(AF_INET, "127.0.0.1", &addr4); |
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status = ares_append_ai_node(AF_INET, port, &addr4, nodes); |
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if (status != ARES_SUCCESS) |
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{ |
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return status; |
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} |
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} |
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return status; |
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} |
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static int ares__system_loopback_addrs(int aftype, |
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unsigned short port, |
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struct ares_addrinfo_node **nodes) |
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{ |
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#if defined(_WIN32) && defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0600 |
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PMIB_UNICASTIPADDRESS_TABLE table; |
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unsigned int i; |
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int status; |
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*nodes = NULL; |
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if (GetUnicastIpAddressTable(aftype, &table) != NO_ERROR) |
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return ARES_ENOTFOUND; |
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for (i=0; i<table->NumEntries; i++) |
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{ |
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if (table->Table[i].InterfaceLuid.Info.IfType != |
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IF_TYPE_SOFTWARE_LOOPBACK) |
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{ |
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continue; |
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} |
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if (table->Table[i].Address.si_family == AF_INET) |
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{ |
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status = ares_append_ai_node(table->Table[i].Address.si_family, port, |
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&table->Table[i].Address.Ipv4.sin_addr, |
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nodes); |
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} |
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else if (table->Table[i].Address.si_family == AF_INET6) |
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{ |
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status = ares_append_ai_node(table->Table[i].Address.si_family, port, |
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&table->Table[i].Address.Ipv6.sin6_addr, |
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nodes); |
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} |
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else |
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{ |
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/* Ignore any others */ |
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continue; |
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} |
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if (status != ARES_SUCCESS) |
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{ |
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goto fail; |
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} |
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} |
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if (*nodes == NULL) |
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status = ARES_ENOTFOUND; |
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fail: |
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FreeMibTable(table); |
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if (status != ARES_SUCCESS) |
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{ |
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ares__freeaddrinfo_nodes(*nodes); |
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*nodes = NULL; |
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} |
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return status; |
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#else |
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/* Not supported on any other OS at this time */ |
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return ARES_ENOTFOUND; |
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#endif |
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} |
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int ares__addrinfo_localhost(const char *name, |
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unsigned short port, |
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const struct ares_addrinfo_hints *hints, |
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struct ares_addrinfo *ai) |
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{ |
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struct ares_addrinfo_node *nodes = NULL; |
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int result; |
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/* Validate family */ |
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switch (hints->ai_family) { |
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case AF_INET: |
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case AF_INET6: |
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case AF_UNSPEC: |
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break; |
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default: |
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return ARES_EBADFAMILY; |
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} |
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ai->name = ares_strdup(name); |
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if(!ai->name) |
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{ |
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goto enomem; |
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} |
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result = ares__system_loopback_addrs(hints->ai_family, port, &nodes); |
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if (result == ARES_ENOTFOUND) |
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{ |
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result = ares__default_loopback_addrs(hints->ai_family, port, &nodes); |
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} |
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ares__addrinfo_cat_nodes(&ai->nodes, nodes); |
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return result; |
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enomem: |
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ares__freeaddrinfo_nodes(nodes); |
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ares_free(ai->name); |
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ai->name = NULL; |
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return ARES_ENOMEM; |
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} |
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