[PATCH] 7006496: Use modern Windows API to retrieve OS DNS servers
Aleks Efimov
aleksej.efimov at oracle.com
Mon Dec 2 13:04:29 UTC 2019
Hi Anuraag,
I've submited your patch to our CI system and I'm observing a bunch of
NPE failures with such stack trace:
java.lang.NullPointerException
at
java.base/sun.net.dns.ResolverConfigurationImpl.allocateListForDelimitedString(ResolverConfigurationImpl.java:108)
at
java.base/sun.net.dns.ResolverConfigurationImpl.stringToList(ResolverConfigurationImpl.java:68)
at
java.base/sun.net.dns.ResolverConfigurationImpl.loadConfig(ResolverConfigurationImpl.java:149)
at
java.base/sun.net.dns.ResolverConfigurationImpl.nameservers(ResolverConfigurationImpl.java:172)
at
jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.platformServersAvailable(DnsContextFactory.java:94)
at
jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.platformServersUsed(DnsContextFactory.java:171)
at
jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.getContext(DnsContextFactory.java:83)
at
jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.urlToContext(DnsContextFactory.java:120)
at
jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.getInitialContext(DnsContextFactory.java:64)
at
java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:730)
at
java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305)
at
java.naming/javax.naming.InitialContext.init(InitialContext.java:236)
at
java.naming/javax.naming.InitialContext.<init>(InitialContext.java:208)
at
java.naming/javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:130)
at LookupWithAnyAttrProp.runTest(LookupWithAnyAttrProp.java:57)
at TestBase.launch(TestBase.java:82)
at TestBase.run(TestBase.java:50)
at LookupWithAnyAttrProp.main(LookupWithAnyAttrProp.java:43)
at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
at
java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at
java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at
com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)
Few examples of failing tests:
test/jdk/com/sun/jndi/dns/FedTests/ListSubInterior.java (and others in
the same folder)
test/jdk/com/sun/jndi/dns/FactoryTests/LookupWithAnyAttrProp.java (and
others in the same folder)
Test platform is: Windows Server 2012 R2 6.3
With Best Regards,
Aleksei
On 25/11/2019 05:09, Anuraag Agrawal wrote:
> Hi Bernd,
>
> Thanks for the look and suggestion. I have updated those comments, as
> well as added several more to explain the native code aspects better
> which I hope helps future readers of the code. Hope it looks better now.
>
> Inline patch follows
>
> diff --git
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> index 2250b3158e..18996f0ee0 100644
> ---
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> +++
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> @@ -25,9 +25,10 @@
>
> package sun.net.dns;
>
> +import java.util.ArrayList;
> import java.util.List;
> -import java.util.LinkedList;
> import java.util.StringTokenizer;
> +import java.util.concurrent.TimeUnit;
>
> /*
> * An implementation of sun.net.ResolverConfiguration for Windows.
> @@ -50,30 +51,69 @@ public class ResolverConfigurationImpl
>
> // Cache timeout (120 seconds) - should be converted into property
> // or configured as preference in the future.
> - private static final int TIMEOUT = 120000;
> + private static final long TIMEOUT_NANOS =
> TimeUnit.SECONDS.toNanos(120);
>
> // DNS suffix list and name servers populated by native method
> private static String os_searchlist;
> private static String os_nameservers;
>
> // Cached lists
> - private static LinkedList<String> searchlist;
> - private static LinkedList<String> nameservers;
> + private static ArrayList<String> searchlist;
> + private static ArrayList<String> nameservers;
>
> - // Parse string that consists of token delimited by space or commas
> - // and return LinkedHashMap
> - private LinkedList<String> stringToList(String str) {
> - LinkedList<String> ll = new LinkedList<>();
> + // Parse string that consists of token delimited by space
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + private ArrayList<String> stringToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
>
> - // comma and space are valid delimiters
> - StringTokenizer st = new StringTokenizer(str, ", ");
> + // String is delimited by space.
> + StringTokenizer st = new StringTokenizer(str, " ");
> while (st.hasMoreTokens()) {
> String s = st.nextToken();
> - if (!ll.contains(s)) {
> - ll.add(s);
> + if (!l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + return l;
> + }
> +
> + // Parse string that consists of token delimited by space
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + // In addition to splitting the string, converts IPv6 addresses to
> + // BSD-style.
> + private ArrayList<String> addressesToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
> +
> + // String is delimited by space
> + StringTokenizer st = new StringTokenizer(str, " ");
> + while (st.hasMoreTokens()) {
> + String s = st.nextToken();
> + if (!s.isEmpty()) {
> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
> + // Not BSD style
> + s = '[' + s + ']';
> + }
> + if (!l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + return l;
> + }
> +
> + private ArrayList<String> allocateListForDelimitedString(String
> str) {
> + int num = 0;
> + for (int i = 0; i < str.length(); i++) {
> + char c = str.charAt(i);
> + // String is space separated list of items
> + if (c == ' ') {
> + num++;
> + }
> + }
> + // Actual num is number of delimiters + 1
> + return new ArrayList<String>(num + 1);
> }
>
> // Load DNS configuration from OS
> @@ -81,28 +121,33 @@ public class ResolverConfigurationImpl
> private void loadConfig() {
> assert Thread.holdsLock(lock);
>
> - // if address have changed then DNS probably changed as well;
> - // otherwise check if cached settings have expired.
> - //
> + // A change in the network address of the machine usually
> indicates
> + // a change in DNS configuration too so we always refresh the
> config
> + // after such a change.
> if (changed) {
> changed = false;
> } else {
> + // Otherwise we refresh if TIMEOUT_NANOS has passed since
> last
> + // load.
> if (lastRefresh >= 0) {
> - long currTime = System.currentTimeMillis();
> - if ((currTime - lastRefresh) < TIMEOUT) {
> + long currTime = System.nanoTime();
> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
> return;
> }
> }
> }
>
> - // load DNS configuration, update timestamp, create
> - // new HashMaps from the loaded configuration
> - //
> - loadDNSconfig0();
> + // Native code that uses Windows API to find out the DNS server
> + // addresses and search suffixes. It builds a space-delimited
> string
> + // of nameservers and domain suffixes and sets them to the static
> + // os_nameservers and os_searchlist. We then split these into
> Java
> + // Lists here.
>
> - lastRefresh = System.currentTimeMillis();
> + // Record the time of update and refresh the lists of addresses /
> + // domain suffixes.
> + lastRefresh = System.nanoTime();
> searchlist = stringToList(os_searchlist);
> - nameservers = stringToList(os_nameservers);
> + nameservers = addressesToList(os_nameservers);
> os_searchlist = null; // can be GC'ed
> os_nameservers = null;
> }
> diff --git
> a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> index f2368bafcb..297a1561ef 100644
> --- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> +++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> @@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
> * for each adapter on the system. Returned in *adapters.
> * Buffer is malloc'd and must be freed (unless error returned)
> */
> -static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES **adapters) {
> - DWORD ret, flags;
> +int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
> **adapters) {
> + DWORD ret;
> IP_ADAPTER_ADDRESSES *adapterInfo;
> ULONG len;
> int try;
> @@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env,
> IP_ADAPTER_ADDRESSES **adapters) {
> }
>
> len = BUFF_SIZE;
> - flags = GAA_FLAG_SKIP_DNS_SERVER;
> - flags |= GAA_FLAG_SKIP_MULTICAST;
> - flags |= GAA_FLAG_INCLUDE_PREFIX;
> ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapterInfo,
> &len);
>
> for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try < MAX_TRIES;
> ++try) {
> @@ -240,7 +237,7 @@ static int ipinflen = 2048;
> */
> int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
> {
> - DWORD ret;
> + DWORD ret, flags;
> MIB_IPADDRTABLE *tableP;
> IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
> ULONG len=ipinflen, count=0;
> @@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv *env,
> netif **netifPP)
> }
> }
> free(tableP);
> - ret = getAdapters (env, &adapters);
> +
> + flags = GAA_FLAG_SKIP_DNS_SERVER;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_INCLUDE_PREFIX;
> + ret = getAdapters (env, flags, &adapters);
> if (ret != ERROR_SUCCESS) {
> goto err;
> }
> diff --git
> a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> index 13b28044a5..83100aa9ad 100644
> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> @@ -30,6 +30,7 @@
> #include <iprtrmib.h>
> #include <time.h>
> #include <assert.h>
> +#include <winsock2.h>
> #include <iphlpapi.h>
>
> #include "jni_util.h"
> @@ -48,6 +49,8 @@
> static jfieldID searchlistID;
> static jfieldID nameserversID;
>
> +extern int getAdapters(JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
> **adapters);
> +
> /*
> * Utility routine to append s2 to s1 with a space delimiter.
> * strappend(s1="abc", "def") => "abc def"
> @@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
> }
>
> /*
> - * Windows 2000/XP
> - *
> - * Use registry approach based on settings described in Appendix C
> - * of "Microsoft Windows 2000 TCP/IP Implementation Details".
> - *
> - * DNS suffix list is obtained from SearchList registry setting. If
> - * this is not specified we compile suffix list based on the
> - * per-connection domain suffix.
> - *
> - * DNS name servers and domain settings are on a per-connection
> - * basic. We therefore enumerate the network adapters to get the
> - * names of each adapter and then query the corresponding registry
> - * settings to obtain NameServer/DhcpNameServer and Domain/DhcpDomain.
> + * Use DNS server addresses returned by GetAdaptersAddresses for
> currently
> + * active interfaces.
> */
> -static int loadConfig(char *sl, char *ns) {
> - IP_ADAPTER_INFO *adapterP;
> - ULONG size;
> - DWORD ret;
> +static int loadConfig(JNIEnv *env, char *sl, char *ns) {
> + IP_ADAPTER_ADDRESSES *adapters, *adapter;
> + IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
> + SOCKADDR *address;
> + IP_ADAPTER_DNS_SUFFIX *suffix;
> + DWORD ret, flags;
> DWORD dwLen;
> ULONG ulType;
> char result[MAX_STR_LEN];
> HANDLE hKey;
> - int gotSearchList = 0;
>
> /*
> * First see if there is a global suffix list specified.
> @@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
> assert(ulType == REG_SZ);
> if (strlen(result) > 0) {
> strappend(sl, result);
> - gotSearchList = 1;
> }
> }
> RegCloseKey(hKey);
> }
>
> - /*
> - * Ask the IP Helper library to enumerate the adapters
> - */
> - size = sizeof(IP_ADAPTER_INFO);
> - adapterP = (IP_ADAPTER_INFO *)malloc(size);
> - if (adapterP == NULL) {
> - return STS_ERROR;
> - }
> - ret = GetAdaptersInfo(adapterP, &size);
> - if (ret == ERROR_BUFFER_OVERFLOW) {
> - IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
> *)realloc(adapterP, size);
> - if (newAdapterP == NULL) {
> - free(adapterP);
> - return STS_ERROR;
> - }
> - adapterP = newAdapterP;
>
> - ret = GetAdaptersInfo(adapterP, &size);
> + // We only need DNS server addresses so skip everything else.
> + flags = GAA_FLAG_SKIP_UNICAST;
> + flags |= GAA_FLAG_SKIP_ANYCAST;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
> + ret = getAdapters(env, flags, &adapters);
> + if (ret != ERROR_SUCCESS) {
> + return STS_ERROR;
> }
>
> - /*
> - * Iterate through the list of adapters as registry settings are
> - * keyed on the adapter name (GUID).
> - */
> - if (ret == ERROR_SUCCESS) {
> - IP_ADAPTER_INFO *curr = adapterP;
> - while (curr != NULL) {
> - char key[MAX_STR_LEN];
> -
> - sprintf(key,
> -
> "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
> - curr->AdapterName);
> -
> - ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
> - key,
> - 0,
> - KEY_READ,
> - (PHKEY)&hKey);
> - if (ret == ERROR_SUCCESS) {
> - DWORD enableDhcp = 0;
> -
> - /*
> - * Is DHCP enabled on this interface
> - */
> - dwLen = sizeof(enableDhcp);
> - ret = RegQueryValueEx(hKey, "EnableDhcp", NULL, &ulType,
> - (LPBYTE)&enableDhcp, &dwLen);
> -
> - /*
> - * If we don't have the suffix list when get the Domain
> - * or DhcpDomain. If DHCP is enabled then Domain overides
> - * DhcpDomain
> - */
> - if (!gotSearchList) {
> - result[0] = '\0';
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "Domain", NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) || (strlen(result) ==
> 0)) &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpDomain",
> NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> - strappend(sl, result);
> - }
> - }
> -
> - /*
> - * Get DNS servers based on NameServer or DhcpNameServer
> - * registry setting. If NameServer is set then it
> overrides
> - * DhcpNameServer (even if DHCP is enabled).
> - */
> - result[0] = '\0';
> + adapter = adapters;
> + while (adapter != NULL) {
> + // Only load config from enabled adapters.
> + if (adapter->OperStatus == IfOperStatusUp) {
> + dnsServer = adapter->FirstDnsServerAddress;
> + while (dnsServer != NULL) {
> + address = dnsServer->Address.lpSockaddr;
> dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "NameServer", NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) || (strlen(result) == 0)) &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpNameServer",
> NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> + ret = WSAAddressToStringA(dnsServer->Address.lpSockaddr,
> + dnsServer->Address.iSockaddrLength, NULL,
> + result, &dwLen);
> + if (ret == 0) {
> strappend(ns, result);
> }
>
> - /*
> - * Finished with this registry key
> - */
> - RegCloseKey(hKey);
> + dnsServer = dnsServer->Next;
> }
>
> - /*
> - * Onto the next adapeter
> - */
> - curr = curr->Next;
> + // Add connection-specific search domains in addition to
> global one.
> + suffix = adapter->FirstDnsSuffix;
> + while (suffix != NULL) {
> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix->String,
> -1,
> + result, sizeof(result), NULL, NULL);
> + if (ret != 0) {
> + strappend(sl, result);
> + }
> +
> + suffix = suffix->Next;
> + }
> }
> - }
>
> - /*
> - * Free the adpater structure
> - */
> - if (adapterP) {
> - free(adapterP);
> + adapter = adapter->Next;
> }
>
> + free(adapters);
> +
> return STS_SL_FOUND & STS_NS_FOUND;
> }
>
> @@ -260,7 +189,7 @@
> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
> jclass cl
> searchlist[0] = '\0';
> nameservers[0] = '\0';
>
> - if (loadConfig(searchlist, nameservers) != STS_ERROR) {
> + if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
>
> /*
> * Populate static fields in sun.net.DefaultResolverConfiguration
>
> On Sun, Nov 24, 2019 at 11:21 PM Bernd Eckenfels
> <ecki at zusammenkunft.net <mailto:ecki at zusammenkunft.net>> wrote:
>
> Hello Anuraag,
>
> The patch looks like a good idea (especially the additional
> cleanup for nanos and arraylist) Just a minor thing I noticed
> there are two comments talking about „comma and space“ but the
> code below will only tokenize by space. Imguess the comment needs
> to be fixed, for the next review round.
>
> Gruss
> Bernd
> --
> http://bernd.eckenfels.net
> ------------------------------------------------------------------------
> *Von:* net-dev <net-dev-bounces at openjdk.java.net
> <mailto:net-dev-bounces at openjdk.java.net>> im Auftrag von Anuraag
> Agrawal <anuraaga at gmail.com <mailto:anuraaga at gmail.com>>
> *Gesendet:* Sonntag, November 24, 2019 10:47 AM
> *An:* net-dev at openjdk.java.net <mailto:net-dev at openjdk.java.net>
> *Betreff:* [PATCH] 7006496: Use modern Windows API to retrieve OS
> DNS servers
> Hello,
>
> While investigating DNS resolution failure using Netty
> (https://github.com/netty/netty/issues/9796), I came across an old
> JDK bug where on Windows, the list of OS name servers includes
> those for disabled interfaces
> (https://bugs.openjdk.java.net/browse/JDK-7006496). This is
> problematic since it will often include values from a previously
> registered network that is not available anymore, hence resolution
> requests would be guaranteed to fail.
>
> The current approach reads DNS name servers from the registry,
> where it isn't possible to read whether an adapter is actually
> enabled or not. However, Windows Vista+ (minimum JDK8+ supported
> Windows) include an API that can be used to examine whether an
> adapter is currently enabled, and also return its DNS servers. So
> I've created this patch to update the name server lookup to use
> this technique. I can confirm that now only name servers from
> enabled adapters are loaded. A side effect is the previous
> approach could only read IPv4 - now IPv6 DNS servers are also
> loaded. The unix implementation seems to do this too, so I don't
> think this should cause issues but I can filter to only IPv4 to be
> more conservative if desired.
>
> I have also cleaned some low hanging fruit in what seems to be
> very old code
>
> - Use ArrayList instead of LinkedList since it can be accurately
> preallocated and is not mutated
> - Use nanoTime instead of currentTimeMillis for refresh timer to
> not cause problems during OS time changes.
> - Simplify tokenizer to only tokenize on space, there is never a
> comma separated list passed to it as we create the list in our JNI
> code
>
> This is my first patch for OpenJDK - happy to accept any feedback.
>
> Thanks for the consideration.
>
> Inlined patch follows (also attached but I've had attached patch
> scrubbed when submitting to jmh-dev before...)
>
> diff --git
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> index 2250b3158e..dde871cf19 100644
> ---
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> +++
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> @@ -25,9 +25,10 @@
>
> package sun.net.dns;
>
> +import java.util.ArrayList;
> import java.util.List;
> -import java.util.LinkedList;
> import java.util.StringTokenizer;
> +import java.util.concurrent.TimeUnit;
>
> /*
> * An implementation of sun.net.ResolverConfiguration for Windows.
> @@ -50,30 +51,65 @@ public class ResolverConfigurationImpl
>
> // Cache timeout (120 seconds) - should be converted into
> property
> // or configured as preference in the future.
> - private static final int TIMEOUT = 120000;
> + private static final long TIMEOUT_NANOS =
> TimeUnit.SECONDS.toNanos(120);
>
> // DNS suffix list and name servers populated by native method
> private static String os_searchlist;
> private static String os_nameservers;
>
> // Cached lists
> - private static LinkedList<String> searchlist;
> - private static LinkedList<String> nameservers;
> + private static ArrayList<String> searchlist;
> + private static ArrayList<String> nameservers;
>
> - // Parse string that consists of token delimited by space or
> commas
> - // and return LinkedHashMap
> - private LinkedList<String> stringToList(String str) {
> - LinkedList<String> ll = new LinkedList<>();
> + // Parse string that consists of token delimited by space
> + // and return ArrayList
> + private ArrayList<String> stringToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
>
> // comma and space are valid delimiters
> - StringTokenizer st = new StringTokenizer(str, ", ");
> + StringTokenizer st = new StringTokenizer(str, " ");
> while (st.hasMoreTokens()) {
> String s = st.nextToken();
> - if (!ll.contains(s)) {
> - ll.add(s);
> + if (!l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + return l;
> + }
> +
> + // Parse string that consists of token delimited by space
> + // and return ArrayList. Converts IPv6 addresses to BSD-style.
> + private ArrayList<String> addressesToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
> +
> + // comma and space are valid delimiters
> + StringTokenizer st = new StringTokenizer(str, " ");
> + while (st.hasMoreTokens()) {
> + String s = st.nextToken();
> + if (!s.isEmpty()) {
> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
> + // Not BSD style
> + s = '[' + s + ']';
> + }
> + if (!l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + return l;
> + }
> +
> + private ArrayList<String>
> allocateListForDelimitedString(String str) {
> + int num = 0;
> + for (int i = 0; i < str.length(); i++) {
> + char c = str.charAt(i);
> + // String is space separated list of items
> + if (c == ' ') {
> + num++;
> + }
> + }
> + // Actual num is number of delimiters + 1
> + return new ArrayList<String>(num + 1);
> }
>
> // Load DNS configuration from OS
> @@ -88,8 +124,8 @@ public class ResolverConfigurationImpl
> changed = false;
> } else {
> if (lastRefresh >= 0) {
> - long currTime = System.currentTimeMillis();
> - if ((currTime - lastRefresh) < TIMEOUT) {
> + long currTime = System.nanoTime();
> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
> return;
> }
> }
> @@ -100,9 +136,9 @@ public class ResolverConfigurationImpl
> //
> loadDNSconfig0();
>
> - lastRefresh = System.currentTimeMillis();
> + lastRefresh = System.nanoTime();
> searchlist = stringToList(os_searchlist);
> - nameservers = stringToList(os_nameservers);
> + nameservers = addressesToList(os_nameservers);
> os_searchlist = null; // can be GC'ed
> os_nameservers = null;
> }
> diff --git
> a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> index f2368bafcb..297a1561ef 100644
> --- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> +++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> @@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
> * for each adapter on the system. Returned in *adapters.
> * Buffer is malloc'd and must be freed (unless error returned)
> */
> -static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES
> **adapters) {
> - DWORD ret, flags;
> +int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
> **adapters) {
> + DWORD ret;
> IP_ADAPTER_ADDRESSES *adapterInfo;
> ULONG len;
> int try;
> @@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env,
> IP_ADAPTER_ADDRESSES **adapters) {
> }
>
> len = BUFF_SIZE;
> - flags = GAA_FLAG_SKIP_DNS_SERVER;
> - flags |= GAA_FLAG_SKIP_MULTICAST;
> - flags |= GAA_FLAG_INCLUDE_PREFIX;
> ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL,
> adapterInfo, &len);
>
> for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try <
> MAX_TRIES; ++try) {
> @@ -240,7 +237,7 @@ static int ipinflen = 2048;
> */
> int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
> {
> - DWORD ret;
> + DWORD ret, flags;
> MIB_IPADDRTABLE *tableP;
> IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
> ULONG len=ipinflen, count=0;
> @@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv
> *env, netif **netifPP)
> }
> }
> free(tableP);
> - ret = getAdapters (env, &adapters);
> +
> + flags = GAA_FLAG_SKIP_DNS_SERVER;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_INCLUDE_PREFIX;
> + ret = getAdapters (env, flags, &adapters);
> if (ret != ERROR_SUCCESS) {
> goto err;
> }
> diff --git
> a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> index 13b28044a5..83100aa9ad 100644
> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> @@ -30,6 +30,7 @@
> #include <iprtrmib.h>
> #include <time.h>
> #include <assert.h>
> +#include <winsock2.h>
> #include <iphlpapi.h>
>
> #include "jni_util.h"
> @@ -48,6 +49,8 @@
> static jfieldID searchlistID;
> static jfieldID nameserversID;
>
> +extern int getAdapters(JNIEnv *env, int flags,
> IP_ADAPTER_ADDRESSES **adapters);
> +
> /*
> * Utility routine to append s2 to s1 with a space delimiter.
> * strappend(s1="abc", "def") => "abc def"
> @@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
> }
>
> /*
> - * Windows 2000/XP
> - *
> - * Use registry approach based on settings described in Appendix C
> - * of "Microsoft Windows 2000 TCP/IP Implementation Details".
> - *
> - * DNS suffix list is obtained from SearchList registry setting. If
> - * this is not specified we compile suffix list based on the
> - * per-connection domain suffix.
> - *
> - * DNS name servers and domain settings are on a per-connection
> - * basic. We therefore enumerate the network adapters to get the
> - * names of each adapter and then query the corresponding registry
> - * settings to obtain NameServer/DhcpNameServer and
> Domain/DhcpDomain.
> + * Use DNS server addresses returned by GetAdaptersAddresses for
> currently
> + * active interfaces.
> */
> -static int loadConfig(char *sl, char *ns) {
> - IP_ADAPTER_INFO *adapterP;
> - ULONG size;
> - DWORD ret;
> +static int loadConfig(JNIEnv *env, char *sl, char *ns) {
> + IP_ADAPTER_ADDRESSES *adapters, *adapter;
> + IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
> + SOCKADDR *address;
> + IP_ADAPTER_DNS_SUFFIX *suffix;
> + DWORD ret, flags;
> DWORD dwLen;
> ULONG ulType;
> char result[MAX_STR_LEN];
> HANDLE hKey;
> - int gotSearchList = 0;
>
> /*
> * First see if there is a global suffix list specified.
> @@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
> assert(ulType == REG_SZ);
> if (strlen(result) > 0) {
> strappend(sl, result);
> - gotSearchList = 1;
> }
> }
> RegCloseKey(hKey);
> }
>
> - /*
> - * Ask the IP Helper library to enumerate the adapters
> - */
> - size = sizeof(IP_ADAPTER_INFO);
> - adapterP = (IP_ADAPTER_INFO *)malloc(size);
> - if (adapterP == NULL) {
> - return STS_ERROR;
> - }
> - ret = GetAdaptersInfo(adapterP, &size);
> - if (ret == ERROR_BUFFER_OVERFLOW) {
> - IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
> *)realloc(adapterP, size);
> - if (newAdapterP == NULL) {
> - free(adapterP);
> - return STS_ERROR;
> - }
> - adapterP = newAdapterP;
>
> - ret = GetAdaptersInfo(adapterP, &size);
> + // We only need DNS server addresses so skip everything else.
> + flags = GAA_FLAG_SKIP_UNICAST;
> + flags |= GAA_FLAG_SKIP_ANYCAST;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
> + ret = getAdapters(env, flags, &adapters);
> + if (ret != ERROR_SUCCESS) {
> + return STS_ERROR;
> }
>
> - /*
> - * Iterate through the list of adapters as registry settings are
> - * keyed on the adapter name (GUID).
> - */
> - if (ret == ERROR_SUCCESS) {
> - IP_ADAPTER_INFO *curr = adapterP;
> - while (curr != NULL) {
> - char key[MAX_STR_LEN];
> -
> - sprintf(key,
> -
> "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
> - curr->AdapterName);
> -
> - ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
> - key,
> - 0,
> - KEY_READ,
> - (PHKEY)&hKey);
> - if (ret == ERROR_SUCCESS) {
> - DWORD enableDhcp = 0;
> -
> - /*
> - * Is DHCP enabled on this interface
> - */
> - dwLen = sizeof(enableDhcp);
> - ret = RegQueryValueEx(hKey, "EnableDhcp", NULL,
> &ulType,
> - (LPBYTE)&enableDhcp, &dwLen);
> -
> - /*
> - * If we don't have the suffix list when get the
> Domain
> - * or DhcpDomain. If DHCP is enabled then Domain
> overides
> - * DhcpDomain
> - */
> - if (!gotSearchList) {
> - result[0] = '\0';
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "Domain", NULL,
> &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) ||
> (strlen(result) == 0)) &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpDomain",
> NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> - strappend(sl, result);
> - }
> - }
> -
> - /*
> - * Get DNS servers based on NameServer or
> DhcpNameServer
> - * registry setting. If NameServer is set then it
> overrides
> - * DhcpNameServer (even if DHCP is enabled).
> - */
> - result[0] = '\0';
> + adapter = adapters;
> + while (adapter != NULL) {
> + // Only load config from enabled adapters.
> + if (adapter->OperStatus == IfOperStatusUp) {
> + dnsServer = adapter->FirstDnsServerAddress;
> + while (dnsServer != NULL) {
> + address = dnsServer->Address.lpSockaddr;
> dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "NameServer", NULL,
> &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) || (strlen(result) ==
> 0)) &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpNameServer",
> NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> + ret =
> WSAAddressToStringA(dnsServer->Address.lpSockaddr,
> + dnsServer->Address.iSockaddrLength, NULL,
> + result, &dwLen);
> + if (ret == 0) {
> strappend(ns, result);
> }
>
> - /*
> - * Finished with this registry key
> - */
> - RegCloseKey(hKey);
> + dnsServer = dnsServer->Next;
> }
>
> - /*
> - * Onto the next adapeter
> - */
> - curr = curr->Next;
> + // Add connection-specific search domains in addition
> to global one.
> + suffix = adapter->FirstDnsSuffix;
> + while (suffix != NULL) {
> + ret = WideCharToMultiByte(CP_UTF8, 0,
> suffix->String, -1,
> + result, sizeof(result), NULL, NULL);
> + if (ret != 0) {
> + strappend(sl, result);
> + }
> +
> + suffix = suffix->Next;
> + }
> }
> - }
>
> - /*
> - * Free the adpater structure
> - */
> - if (adapterP) {
> - free(adapterP);
> + adapter = adapter->Next;
> }
>
> + free(adapters);
> +
> return STS_SL_FOUND & STS_NS_FOUND;
> }
>
> @@ -260,7 +189,7 @@
> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv
> *env, jclass cl
> searchlist[0] = '\0';
> nameservers[0] = '\0';
>
> - if (loadConfig(searchlist, nameservers) != STS_ERROR) {
> + if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
>
> /*
> * Populate static fields in
> sun.net.DefaultResolverConfiguration
>
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