DNS 解析器（DNS Resolver)

DNS 解析器（DNS Resolver）

DNS 解析器模块可保护用户免受 DNS 拦截和配置更新攻击，并改进了 DNS 解析的网络性能。此模块包含用于实现 DNS 桩解析器的代码，该解析器可将 www.google.com 等名称转换为 IP 地址（例如 2001:db8::1）。DNS 桩解析器支持 Java API 元素（如 InetAddress#getAllByName 和 Network#getAllByName）以及原生网络功能，且可发送和接收 DNS 查询以及缓存结果。

Android 10 中的变化

在搭载 Android 9 及更低版本的设备上，DNS 解析器代码分布在 Bionic 和 netd 上。DNS 查找操作集中在 netd 守护程序中，以便进行系统级缓存，而应用在 Bionic 中调用函数（例如 getaddrinfo）。查询会通过 UNIX 套接字发送到 /dev/socket/dnsproxyd，再到 netd 守护程序，该守护程序会解析请求并再次调用 getaddrinfo，以发出 DNS 查找请求，然后它会缓存结果以供其他应用使用。DNS 解析器实现主要包含在 bionic/libc/dns/ 中，部分包含在 system/netd/server/dns 中。

Android 10 将 DNS 解析器代码移至 system/netd/resolv,，将其转换为 C++，然后对代码进行了翻新和重构。由于应用兼容性方面的原因，Bionic 中的代码继续存在，但系统不会再调用它们。以下源文件路径受到重构的影响：

• bionic/libc/dns
• system/netd/client
• system/netd/server/dns
• system/netd/server/DnsProxyListener.*
• system/netd/resolv

---

（1）获取ip地址（域名–>IP地址）

ConnectivityService.updateDnses() ->

DnsManager.setDnsConfigurationForNetwork() ->

mDnsResolver.setResolverConfiguration() -> IDnsResolver.aidl ()

DnsResolverService.setResolverConfiguration()  ->

ResolverController.setResolverConfiguration() ->

res_cache.int resolv_set_nameservers_for_net() ->

getaddrinfo.getaddrinfo_numeric() -> getaddrinfo.android_getaddrinfofornetcontext(hostname, servname, &hints, &netcontext, result);

 

(2)DNS server list 设置(set name servers for a network)

_resolv_set_nameservers_for_net

 

---

http://androidxref.com/9.0.0_r3/xref/libcore/ojluni/src/main/java/java/net/InetAddress.java#1105

1. 1077 /**

2. 1078 * Determines the IP address of a host, given the host's name.

3. 1097 * @param host the specified host, or {@code null}.

4. 1098 * @return an IP address for the given host name.

5. 1104 */

6. 1105 public static InetAddress getByName(String host)

7. 1106 throws UnknownHostException {

8. 1107 // Android-changed: Rewritten on the top of Libcore.os.

9. 1108 return impl.lookupAllHostAddr(host, NETID_UNSET)[0];

10. 1109 }

11.  

12. 1111 /**

13. 1112 * Given the name of a host, returns an array of its IP addresses,

14. 1113 * based on the configured name service on the system.

15. 1139 * @param host the name of the host, or {@code null}.

16. 1140 * @return an array of all the IP addresses for a given host name.

17. 1149 */

18. 1150 public static InetAddress[] getAllByName(String host)

19. 1151 throws UnknownHostException {

20. 1152 // Android-changed: Resolves a hostname using Libcore.os.

21. 1153 // Also, returns both the Inet4 and Inet6 loopback for null/empty host

22. 1154 return impl.lookupAllHostAddr(host, NETID_UNSET).clone();

23. 1155 }

24.  
25.  

lookupAllHostAddr在Android M上的名字叫做getAllByNameImpl

http://androidxref.com/9.0.0_r3/xref/libcore/ojluni/src/main/java/java/net/Inet6AddressImpl.java#88

1. 79 // BEGIN Android-changed: Rewrote hostname lookup methods on top of Libcore.os.

2. 80 /*

3. 81 public native String getLocalHostName() throws UnknownHostException;

4. 82 public native InetAddress[]

5. 83 lookupAllHostAddr(String hostname) throws UnknownHostException;

6. 84 public native String getHostByAddr(byte[] addr) throws UnknownHostException;

7. 85 private native boolean isReachable0(byte[] addr, int scope, int timeout, byte[] inf, int ttl, int if_scope) throws IOException;

8. 86 */

9. 87 @Override

10. 88 public InetAddress[] lookupAllHostAddr(String host, int netId) throws UnknownHostException {

11. 89 if (host == null || host.isEmpty()) {

12. 90 // Android-changed: Return both the Inet4 and Inet6 loopback addresses

13. 91 // when host == null or empty.

14. 92 return loopbackAddresses();

15. 93 }

16. 94

17. 95 // Is it a numeric address?

18. 96 InetAddress result = InetAddress.parseNumericAddressNoThrow(host);

19. 97 if (result != null) {

20. 98 result = InetAddress.disallowDeprecatedFormats(host, result);

21. 99 if (result == null) {

22. 100 throw new UnknownHostException("Deprecated IPv4 address format: " + host);

23. 101 }

24. 102 return new InetAddress[] { result };

25. 103 }

26. 104

27. 105 return lookupHostByName(host, netId);

28. 106 }

29.  

30. 323 // BEGIN Android-changed: Let loopbackAddresses() return both Inet4 and Inet6 loopbacks.

31. 324 @Override

32. 325 public InetAddress[] loopbackAddresses() {

33. 326 synchronized (Inet6AddressImpl.class) {

34. 327 // We avoid initializing anyLocalAddress during <clinit> to avoid issues

35. 328 // caused by the dependency chains of these classes. InetAddress depends on

36. 329 // InetAddressImpl, but Inet6Address & Inet4Address are its subclasses.

37. 330 // Also see {@code anyLocalAddress).

38. 331 if (loopbackAddresses == null) {

39. 332 loopbackAddresses = new InetAddress[]{Inet6Address.LOOPBACK, Inet4Address.LOOPBACK};

40. 333 }

41. 334

42. 335 return loopbackAddresses;

43. 336 }

44. 337 }

45.  
46.  

http://androidxref.com/9.0.0_r3/xref/libcore/ojluni/src/main/java/java/net/InetAddress.java#1622

1. 1622 static InetAddress parseNumericAddressNoThrow(String address) {

2. 1623 // Accept IPv6 addresses (only) in square brackets for compatibility.

3. 1624 if (address.startsWith("[") && address.endsWith("]") && address.indexOf(':') != -1) {

4. 1625 address = address.substring(1, address.length() - 1);

5. 1626 }

6. 1627 StructAddrinfo hints = new StructAddrinfo();

7. 1628 hints.ai_flags = AI_NUMERICHOST;

8. 1629 InetAddress[] addresses = null;

9. 1630 try {

10. 1631 addresses = Libcore.os.android_getaddrinfo(address, hints, NETID_UNSET);

11. 1632 } catch (GaiException ignored) {

12. 1633 }

13. 1634 return (addresses != null) ? addresses[0] : null;

14. 1635 }

http://androidxref.com/9.0.0_r3/xref/libcore/ojluni/src/main/java/java/net/Inet6AddressImpl.java#115

1. 108 /**

2. 109 * Resolves a hostname to its IP addresses using a cache.

3. 110 *

4. 111 * @param host the hostname to resolve.

5. 112 * @param netId the network to perform resolution upon.

6. 113 * @return the IP addresses of the host.

7. 114 */

8. 115 private static InetAddress[] lookupHostByName(String host, int netId)

9. 116 throws UnknownHostException {

10. 117 BlockGuard.getThreadPolicy().onNetwork();

11. 118 // Do we have a result cached?

12. 119 Object cachedResult = addressCache.get(host, netId);

13. 120 if (cachedResult != null) {

14. 121 if (cachedResult instanceof InetAddress[]) {

15. 122 // A cached positive result.

16. 123 return (InetAddress[]) cachedResult;

17. 124 } else {

18. 125 // A cached negative result.

19. 126 throw new UnknownHostException((String) cachedResult);

20. 127 }

21. 128 }

22. 129 try {

23. 130 StructAddrinfo hints = new StructAddrinfo();

24. 131 hints.ai_flags = AI_ADDRCONFIG;

25. 132 hints.ai_family = AF_UNSPEC;

26. 133 // If we don't specify a socket type, every address will appear twice, once

27. 134 // for SOCK_STREAM and one for SOCK_DGRAM. Since we do not return the family

28. 135 // anyway, just pick one.

29. 136 hints.ai_socktype = SOCK_STREAM;

30. 137 InetAddress[] addresses = Libcore.os.android_getaddrinfo(host, hints, netId);

31. 138 // TODO: should getaddrinfo set the hostname of the InetAddresses it returns?

32. 139 for (InetAddress address : addresses) {

33. 140 address.holder().hostName = host;

34. 141 address.holder().originalHostName = host;

35. 142 }

36. 143 addressCache.put(host, netId, addresses);

37. 144 return addresses;

38. 145 } catch (GaiException gaiException) {

39. 146 // If the failure appears to have been a lack of INTERNET permission, throw a clear

40. 147 // SecurityException to aid in debugging this common mistake.

41. 148 // http://code.google.com/p/android/issues/detail?id=15722

42. 149 if (gaiException.getCause() instanceof ErrnoException) {

43. 150 if (((ErrnoException) gaiException.getCause()).errno == EACCES) {

44. 151 throw new SecurityException("Permission denied (missing INTERNET permission?)", gaiException);

45. 152 }

46. 153 }

47. 154 // Otherwise, throw an UnknownHostException.

48. 155 String detailMessage = "Unable to resolve host \"" + host + "\": " + Libcore.os.gai_strerror(gaiException.error);

49. 156 addressCache.putUnknownHost(host, netId, detailMessage);

50. 157 throw gaiException.rethrowAsUnknownHostException(detailMessage);

51. 158 }

52. 159 }

上面都调用了Libcore.os.android_getaddrinfo

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/java/libcore/io/Libcore.java#19

1. 19public final class Libcore {

2. 20 private Libcore() { }

3. 21

4. 22 /**

5. 23 * Direct access to syscalls. Code should strongly prefer using {@link #os}

6. 24 * unless it has a strong reason to bypass the helpful checks/guards that it

7. 25 * provides.

8. 26 */

9. 27 public static Os rawOs = new Linux();

10. 28

11. 29 /**

12. 30 * Access to syscalls with helpful checks/guards.

13. 31 */

14. 32 public static Os os = new BlockGuardOs(rawOs);

15. 33}

Os对象是一系列系统调用的抽象接口，从LibCore.java中可以看出它是通过Linux这个类实现的

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/java/libcore/io/Linux.java#53

1. 48public final class Linux implements Os {

2. 49 Linux() { }

3.  

4. 53 public native InetAddress[] android_getaddrinfo(String node, StructAddrinfo hints, int netId) throws GaiException;

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/java/libcore/io/BlockGuardOs.java#164

1. 40/**

2. 41 * Informs BlockGuard of any activity it should be aware of.

3. 42 */

4. 43public class BlockGuardOs extends ForwardingOs {

5. 44 public BlockGuardOs(Os os) {

6. 45 super(os);

7. 46 }

8.  
9.  

10. 164 @Override public InetAddress[] android_getaddrinfo(String node, StructAddrinfo hints, int netId) throws GaiException {

11. 165 // With AI_NUMERICHOST flag set, the node must a numerical network address, therefore no

12. 166 // host address lookups will be performed. In this case, it is fine to perform on main

13. 167 // thread.

14. 168 boolean isNumericHost = (hints.ai_flags & AI_NUMERICHOST) != 0;

15. 169 if (!isNumericHost) {

16. 170 BlockGuard.getThreadPolicy().onNetwork();

17. 171 }

18. 172 return os.android_getaddrinfo(node, hints, netId);

19. 173 }

再找OS类

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/java/libcore/io/Os.java#50

1. 47public interface Os {

2. 50 public InetAddress[] android_getaddrinfo(String node, StructAddrinfo hints, int netId) throws GaiException;

参考

• android 从java到C层文件读取流程
• 深入理解Android的file.exists()

得知Linux.java通过JNI (libcore_io_Linux.cpp)调用linux的posix API，那么知道了，C层的实现都在libcore_io_Linux.cpp中，咱们来看下。

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/native/libcore_io_Linux.cpp#1244

1. 1244static jobjectArray Linux_android_getaddrinfo(JNIEnv* env, jobject, jstring javaNode,

2. 1245 jobject javaHints, jint netId) {

3. 1246 ScopedUtfChars node(env, javaNode);

4. 1247 if (node.c_str() == NULL) {

5. 1248 return NULL;

6. 1249 }

7. 1250

8. 1251 static jfieldID flagsFid = env->GetFieldID(JniConstants::structAddrinfoClass, "ai_flags", "I");

9. 1252 static jfieldID familyFid = env->GetFieldID(JniConstants::structAddrinfoClass, "ai_family", "I");

10. 1253 static jfieldID socktypeFid = env->GetFieldID(JniConstants::structAddrinfoClass, "ai_socktype", "I");

11. 1254 static jfieldID protocolFid = env->GetFieldID(JniConstants::structAddrinfoClass, "ai_protocol", "I");

12. 1255

13. 1256 addrinfo hints;

14. 1257 memset(&hints, 0, sizeof(hints));

15. 1258 hints.ai_flags = env->GetIntField(javaHints, flagsFid);

16. 1259 hints.ai_family = env->GetIntField(javaHints, familyFid);

17. 1260 hints.ai_socktype = env->GetIntField(javaHints, socktypeFid);

18. 1261 hints.ai_protocol = env->GetIntField(javaHints, protocolFid);

19. 1262

20. 1263 addrinfo* addressList = NULL;

21. 1264 errno = 0;

22. 1265 int rc = android_getaddrinfofornet(node.c_str(), NULL, &hints, netId, 0, &addressList);

23. 1266 std::unique_ptr<addrinfo, addrinfo_deleter> addressListDeleter(addressList);

24. 1267 if (rc != 0) {

25. 1268 throwGaiException(env, "android_getaddrinfo", rc);

26. 1269 return NULL;

27. 1270 }

28. 1271

29. 1272 // Count results so we know how to size the output array.

30. 1273 int addressCount = 0;

31. 1274 for (addrinfo* ai = addressList; ai != NULL; ai = ai->ai_next) {

32. 1275 if (ai->ai_family == AF_INET || ai->ai_family == AF_INET6) {

33. 1276 ++addressCount;

34. 1277 } else {

35. 1278 ALOGE("android_getaddrinfo unexpected ai_family %i", ai->ai_family);

36. 1279 }

37. 1280 }

38. 1281 if (addressCount == 0) {

39. 1282 return NULL;

40. 1283 }

41. 1284

42. 1285 // Prepare output array.

43. 1286 jobjectArray result = env->NewObjectArray(addressCount, JniConstants::inetAddressClass, NULL);

44. 1287 if (result == NULL) {

45. 1288 return NULL;

46. 1289 }

47. 1290

48. 1291 // Examine returned addresses one by one, save them in the output array.

49. 1292 int index = 0;

50. 1293 for (addrinfo* ai = addressList; ai != NULL; ai = ai->ai_next) {

51. 1294 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) {

52. 1295 // Unknown address family. Skip this address.

53. 1296 ALOGE("android_getaddrinfo unexpected ai_family %i", ai->ai_family);

54. 1297 continue;

55. 1298 }

56. 1299

57. 1300 // Convert each IP address into a Java byte array.

58. 1301 sockaddr_storage& address = *reinterpret_cast<sockaddr_storage*>(ai->ai_addr);

59. 1302 ScopedLocalRef<jobject> inetAddress(env, sockaddrToInetAddress(env, address, NULL));

60. 1303 if (inetAddress.get() == NULL) {

61. 1304 return NULL;

62. 1305 }

63. 1306 env->SetObjectArrayElement(result, index, inetAddress.get());

64. 1307 ++index;

65. 1308 }

66. 1309 return result;

67. 1310}

调用android_getaddrinfofornet()

http://androidxref.com/9.0.0_r3/xref/libcore/luni/src/main/native/Portability.h#28

1. 28static inline int android_getaddrinfofornet(const char* hostname, const char* servname,

2. 29 const struct addrinfo* hints, unsigned /*netid*/, unsigned /*mark*/, struct addrinfo** res) {

3. 30 return getaddrinfo(hostname, servname, hints, res);

4. 31}

最终调用到bionic/libc/dns/net/getaddrinfo.c

http://androidxref.com/9.0.0_r3/xref/bionic/libc/dns/net/getaddrinfo.c#564

1. 562__BIONIC_WEAK_FOR_NATIVE_BRIDGE

2. 563int

3. 564getaddrinfo(const char *hostname, const char *servname,

4. 565 const struct addrinfo *hints, struct addrinfo **res)

5. 566{

6. 567 return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res);

7. 568}

8.  

9. 570__BIONIC_WEAK_FOR_NATIVE_BRIDGE

10. 571int

11. 572android_getaddrinfofornet(const char *hostname, const char *servname,

12. 573 const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)

13. 574{

14. 575 struct android_net_context netcontext = {

15. 576 .app_netid = netid,

16. 577 .app_mark = mark,

17. 578 .dns_netid = netid,

18. 579 .dns_mark = mark,

19. 580 .uid = NET_CONTEXT_INVALID_UID,

20. 581 };

21. 582 return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res);

22. 583}

23. 584

24. 585__BIONIC_WEAK_FOR_NATIVE_BRIDGE

25. 586int

26. 587android_getaddrinfofornetcontext(const char *hostname, const char *servname,

27. 588 const struct addrinfo *hints, const struct android_net_context *netcontext,

28. 589 struct addrinfo **res)

29. 590{

30. 591 struct addrinfo sentinel;

31. 592 struct addrinfo *cur;

32. 593 int error = 0;

33. 594 struct addrinfo ai;

34. 595 struct addrinfo ai0;

35. 596 struct addrinfo *pai;

36. 597 const struct explore *ex;

37. 598

38. 599 /* hostname is allowed to be NULL */

39. 600 /* servname is allowed to be NULL */

40. 601 /* hints is allowed to be NULL */

41. 602 assert(res != NULL);

42. 603 assert(netcontext != NULL);

43. 604 memset(&sentinel, 0, sizeof(sentinel));

44. 605 cur = &sentinel;

45. 606 pai = &ai;

46. 607 pai->ai_flags = 0;

47. 608 pai->ai_family = PF_UNSPEC;

48. 609 pai->ai_socktype = ANY;

49. 610 pai->ai_protocol = ANY;

50. 611 pai->ai_addrlen = 0;

51. 612 pai->ai_canonname = NULL;

52. 613 pai->ai_addr = NULL;

53. 614 pai->ai_next = NULL;

54. 615

55. 616 if (hostname == NULL && servname == NULL)

56. 617 return EAI_NONAME;

57. 618 if (hints) {

58. 619 /* error check for hints */

59. 620 if (hints->ai_addrlen || hints->ai_canonname ||

60. 621 hints->ai_addr || hints->ai_next)

61. 622 ERR(EAI_BADHINTS); /* xxx */

62. 623 if (hints->ai_flags & ~AI_MASK)

63. 624 ERR(EAI_BADFLAGS);

64. 625 switch (hints->ai_family) {

65. 626 case PF_UNSPEC:

66. 627 case PF_INET:

67. 628#ifdef INET6

68. 629 case PF_INET6:

69. 630#endif

70. 631 break;

71. 632 default:

72. 633 ERR(EAI_FAMILY);

73. 634 }

74. 635 memcpy(pai, hints, sizeof(*pai));

75. 636

76. 637 /*

77. 638 * if both socktype/protocol are specified, check if they

78. 639 * are meaningful combination.

79. 640 */

80. 641 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {

81. 642 for (ex = explore; ex->e_af >= 0; ex++) {

82. 643 if (pai->ai_family != ex->e_af)

83. 644 continue;

84. 645 if (ex->e_socktype == ANY)

85. 646 continue;

86. 647 if (ex->e_protocol == ANY)

87. 648 continue;

88. 649 if (pai->ai_socktype == ex->e_socktype

89. 650 && pai->ai_protocol != ex->e_protocol) {

90. 651 ERR(EAI_BADHINTS);

91. 652 }

92. 653 }

93. 654 }

94. 655 }

95. 656

96. 657 /*

97. 658 * check for special cases. (1) numeric servname is disallowed if

98. 659 * socktype/protocol are left unspecified. (2) servname is disallowed

99. 660 * for raw and other inet{,6} sockets.

100. 661 */

101. 662 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)

102. 663#ifdef PF_INET6

103. 664 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)

104. 665#endif

105. 666 ) {

106. 667 ai0 = *pai; /* backup *pai */

107. 668

108. 669 if (pai->ai_family == PF_UNSPEC) {

109. 670#ifdef PF_INET6

110. 671 pai->ai_family = PF_INET6;

111. 672#else

112. 673 pai->ai_family = PF_INET;

113. 674#endif

114. 675 }

115. 676 error = get_portmatch(pai, servname);

116. 677 if (error)

117. 678 ERR(error);

118. 679

119. 680 *pai = ai0;

120. 681 }

121. 682

122. 683 ai0 = *pai;

123. 684

124. 685 /* NULL hostname, or numeric hostname */

125. 686 for (ex = explore; ex->e_af >= 0; ex++) {

126. 687 *pai = ai0;

127. 688

128. 689 /* PF_UNSPEC entries are prepared for DNS queries only */

129. 690 if (ex->e_af == PF_UNSPEC)

130. 691 continue;

131. 692

132. 693 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))

133. 694 continue;

134. 695 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))

135. 696 continue;

136. 697 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))

137. 698 continue;

138. 699

139. 700 if (pai->ai_family == PF_UNSPEC)

140. 701 pai->ai_family = ex->e_af;

141. 702 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)

142. 703 pai->ai_socktype = ex->e_socktype;

143. 704 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)

144. 705 pai->ai_protocol = ex->e_protocol;

145. 706

146. 707 if (hostname == NULL)

147. 708 error = explore_null(pai, servname, &cur->ai_next);

148. 709 else

149. 710 error = explore_numeric_scope(pai, hostname, servname,

150. 711 &cur->ai_next);

151. 712

152. 713 if (error)

153. 714 goto free;

154. 715

155. 716 while (cur->ai_next)

156. 717 cur = cur->ai_next;

157. 718 }

158. 719

159. 720 /*

160. 721 * XXX

161. 722 * If numeric representation of AF1 can be interpreted as FQDN

162. 723 * representation of AF2, we need to think again about the code below.

163. 724 */

164. 725 if (sentinel.ai_next)

165. 726 goto good;

166. 727

167. 728 if (hostname == NULL)

168. 729 ERR(EAI_NODATA);

169. 730 if (pai->ai_flags & AI_NUMERICHOST)

170. 731 ERR(EAI_NONAME);

171. 732

172. 733#if defined(__ANDROID__)

173. 734 int gai_error = android_getaddrinfo_proxy(

174. 735 hostname, servname, hints, res, netcontext->app_netid);

175. 736 if (gai_error != EAI_SYSTEM) {

176. 737 return gai_error;

177. 738 }

178. 739#endif

179. 740

180. 741 /*

181. 742 * hostname as alphabetical name.

182. 743 * we would like to prefer AF_INET6 than AF_INET, so we'll make a

183. 744 * outer loop by AFs.

184. 745 */

185. 746 for (ex = explore; ex->e_af >= 0; ex++) {

186. 747 *pai = ai0;

187. 748

188. 749 /* require exact match for family field */

189. 750 if (pai->ai_family != ex->e_af)

190. 751 continue;

191. 752

192. 753 if (!MATCH(pai->ai_socktype, ex->e_socktype,

193. 754 WILD_SOCKTYPE(ex))) {

194. 755 continue;

195. 756 }

196. 757 if (!MATCH(pai->ai_protocol, ex->e_protocol,

197. 758 WILD_PROTOCOL(ex))) {

198. 759 continue;

199. 760 }

200. 761

201. 762 if (pai->ai_socktype == ANY && ex->e_socktype != ANY)

202. 763 pai->ai_socktype = ex->e_socktype;

203. 764 if (pai->ai_protocol == ANY && ex->e_protocol != ANY)

204. 765 pai->ai_protocol = ex->e_protocol;

205. 766

206. 767 error = explore_fqdn(

207. 768 pai, hostname, servname, &cur->ai_next, netcontext);

208. 769

209. 770 while (cur && cur->ai_next)

210. 771 cur = cur->ai_next;

211. 772 }

212. 773

213. 774 /* XXX */

214. 775 if (sentinel.ai_next)

215. 776 error = 0;

216. 777

217. 778 if (error)

218. 779 goto free;

219. 780 if (error == 0) {

220. 781 if (sentinel.ai_next) {

221. 782 good:

222. 783 *res = sentinel.ai_next;

223. 784 return SUCCESS;

224. 785 } else

225. 786 error = EAI_FAIL;

226. 787 }

227. 788 free:

228. 789 bad:

229. 790 if (sentinel.ai_next)

230. 791 freeaddrinfo(sentinel.ai_next);

231. 792 *res = NULL;

232. 793 return error;

233. 794}