e Re: [PATCH] 7006496: Use modern Windows API to retrieve OS DNS servers
Aleks Efimov
aleksej.efimov at oracle.com
Thu Jan 9 17:17:15 UTC 2020
Hi Anuuraag,
Latest webrev: http://cr.openjdk.java.net/~aefimov/anuraaga/7006496/05/
Looks fine to me
CI is also happy
Best Regards,
Aleksei
On 09/01/2020 15:22, Anuraag Agrawal wrote:
> Hi all,
>
> Apologies for the spam. I made one more tweak to follow up the
> previous, and removed the default value of -1 for lastRefresh. Now
> that there is no semantic meaning to -1, I think unspecified default
> (effectively zero) is more appropriate and easy to reason about.
>
> 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..aefe44e9b3 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 +25,9 @@
>
> 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.
> @@ -42,38 +42,64 @@ public class ResolverConfigurationImpl
> // Resolver options
> private final Options opts;
>
> - // Addresses have changed
> - private static boolean changed = false;
> + // Addresses have changed. We default to true to make sure we
> + // resolve the first time it is requested.
> + private static boolean changed = true;
>
> // Time of last refresh.
> - private static long lastRefresh = -1;
> + private static long lastRefresh;
>
> // 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;
> -
> - // 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<>();
> -
> - // comma and space are valid delimiters
> - StringTokenizer st = new StringTokenizer(str, ", ");
> - while (st.hasMoreTokens()) {
> - String s = st.nextToken();
> - if (!ll.contains(s)) {
> - ll.add(s);
> + private static ArrayList<String> searchlist;
> + private static ArrayList<String> nameservers;
> +
> + // Parse string that consists of token delimited by comma
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + private ArrayList<String> stringToList(String str) {
> + // String is delimited by comma.
> + String[] tokens = str.split(",");
> + ArrayList<String> l = new ArrayList<>(tokens.length);
> + for (String s : tokens) {
> + if (!s.isEmpty() && !l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + l.trimToSize();
> + return l;
> + }
> +
> + // Parse string that consists of token delimited by comma
> + // 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) {
> + // String is delimited by comma
> + String[] tokens = str.split(",");
> + ArrayList<String> l = new ArrayList<>(tokens.length);
> +
> + for (String s : tokens) {
> + if (!s.isEmpty()) {
> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
> + // Not BSD style
> + s = '[' + s + ']';
> + }
> + if (!s.isEmpty() && !l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + l.trimToSize();
> + return l;
> }
>
> // Load DNS configuration from OS
> @@ -81,28 +107,34 @@ 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 {
> - if (lastRefresh >= 0) {
> - long currTime = System.currentTimeMillis();
> - if ((currTime - lastRefresh) < TIMEOUT) {
> - return;
> - }
> + // Otherwise we refresh if TIMEOUT_NANOS has passed since
> last
> + // load.
> + long currTime = System.nanoTime();
> + // lastRefresh will always have been set once because we
> start with
> + // changed = true.
> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
> + return;
> }
> }
>
> - // load DNS configuration, update timestamp, create
> - // new HashMaps from the loaded configuration
> - //
> + // Native code that uses Windows API to find out the DNS server
> + // addresses and search suffixes. It builds a comma-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.
> loadDNSconfig0();
>
> - 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..e830b8e70b 100644
> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights
> reserved.
> + * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights
> reserved.
> * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
> *
> * This code is free software; you can redistribute it and/or modify it
> @@ -24,17 +24,15 @@
> */
>
> #include <stdlib.h>
> -#include <windows.h>
> #include <stdio.h>
> #include <stddef.h>
> -#include <iprtrmib.h>
> #include <time.h>
> #include <assert.h>
> -#include <iphlpapi.h>
>
> +#include "net_util.h"
> #include "jni_util.h"
>
> -#define MAX_STR_LEN 256
> +#define MAX_STR_LEN 1024
>
> #define STS_NO_CONFIG 0x0 /* no configuration found */
> #define STS_SL_FOUND 0x1 /* search list found */
> @@ -48,9 +46,11 @@
> 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"
> + * Utility routine to append s2 to s1 with a comma delimiter.
> + * strappend(s1="abc", "def") => "abc,def"
> * strappend(s1="", "def") => "def
> */
> void strappend(char *s1, char *s2) {
> @@ -60,41 +60,32 @@ void strappend(char *s1, char *s2) {
> return;
>
> len = strlen(s1)+1;
> - if (s1[0] != 0) /* needs space character */
> + if (s1[0] != 0) /* needs comma character */
> len++;
> if (len + strlen(s2) > MAX_STR_LEN) /* insufficient space */
> return;
>
> if (s1[0] != 0) {
> - strcat(s1, " ");
> + strcat(s1, ",");
> }
> strcat(s1, 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;
> + WCHAR *suffix;
> + DWORD ret, flags;
> DWORD dwLen;
> ULONG ulType;
> char result[MAX_STR_LEN];
> HANDLE hKey;
> - int gotSearchList = 0;
> + SOCKADDR *sockAddr;
> + struct sockaddr_in6 *sockAddrIpv6;
>
> /*
> * First see if there is a global suffix list specified.
> @@ -112,128 +103,74 @@ 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);
> + adapter = adapters;
> + while (adapter != NULL) {
> + // Only load config from enabled adapters.
> + if (adapter->OperStatus == IfOperStatusUp) {
> + dnsServer = adapter->FirstDnsServerAddress;
> + while (dnsServer != NULL) {
> + sockAddr = dnsServer->Address.lpSockaddr;
> + if (sockAddr->sa_family == AF_INET6) {
> + sockAddrIpv6 = (struct sockaddr_in6 *)sockAddr;
> + if (sockAddrIpv6->sin6_scope_id != 0) {
> + // An address with a scope is either
> link-local or
> + // site-local, which aren't valid for DNS
> queries so
> + // we can skip them.
> + dnsServer = dnsServer->Next;
> + continue;
> }
> }
>
> - /*
> - * 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';
> 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(sockAddr,
> + 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->DnsSuffix;
> + if (suffix != NULL) {
> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix, -1,
> + result, sizeof(result), NULL, NULL);
> + if (ret != 0) {
> + strappend(sl, result);
> + }
> + }
> }
> - }
>
> - /*
> - * Free the adpater structure
> - */
> - if (adapterP) {
> - free(adapterP);
> + adapter = adapter->Next;
> }
>
> + free(adapters);
> +
> return STS_SL_FOUND & STS_NS_FOUND;
> }
>
>
> /*
> - * Initialize JNI field IDs.
> + * Initialize JNI field IDs and classes.
> */
> JNIEXPORT void JNICALL
> Java_sun_net_dns_ResolverConfigurationImpl_init0(JNIEnv *env, jclass cls)
> @@ -260,7 +197,7 @@
> 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
> @@ -272,8 +209,6 @@
> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
> jclass cl
> obj = (*env)->NewStringUTF(env, nameservers);
> CHECK_NULL(obj);
> (*env)->SetStaticObjectField(env, cls, nameserversID, obj);
> - } else {
> - JNU_ThrowOutOfMemoryError(env, "native memory allocation
> failed");
> }
> }
>
>
>
> On Fri, Jan 10, 2020 at 12:17 AM Anuraag Agrawal <anuraaga at gmail.com
> <mailto:anuraaga at gmail.com>> wrote:
>
> Hi Daniel,
>
> Thanks for the review!
>
> On Thu, Jan 9, 2020 at 9:04 PM Daniel Fuchs
> <daniel.fuchs at oracle.com <mailto:daniel.fuchs at oracle.com>> wrote:
>
> Hi,
>
> Two small remarks:
>
> ResolverConfigurationImpl.java:
>
> 71 if (!l.contains(s)) {
>
> Maybe empty strings should be skipped here too.
>
>
> Makes sense, added the check.
>
>
> I believe it would be more correct to change this line:
>
> 117 if (lastRefresh >= 0) {
>
> to
>
> 117 if (lastRefresh != -1) {
>
> as System.nanoTime() can return negative values.
>
>
> Had never realized nanoTime can return negative values, I have to
> check all my other code for bugs now ;) I have gone ahead and
> removed this check altogether, instead defaulting "changed" to
> true so we always load on the first time through. I think this
> should be the most precise.
>
> 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..0f161ea4a8 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 +25,9 @@
>
> 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.
> @@ -42,38 +42,64 @@ public class ResolverConfigurationImpl
> // Resolver options
> private final Options opts;
>
> - // Addresses have changed
> - private static boolean changed = false;
> + // Addresses have changed. We default to true to make sure we
> + // resolve the first time it is requested.
> + private static boolean changed = true;
>
> // Time of last refresh.
> private static long lastRefresh = -1;
>
> // 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;
> -
> - // 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<>();
> -
> - // comma and space are valid delimiters
> - StringTokenizer st = new StringTokenizer(str, ", ");
> - while (st.hasMoreTokens()) {
> - String s = st.nextToken();
> - if (!ll.contains(s)) {
> - ll.add(s);
> + private static ArrayList<String> searchlist;
> + private static ArrayList<String> nameservers;
> +
> + // Parse string that consists of token delimited by comma
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + private ArrayList<String> stringToList(String str) {
> + // String is delimited by comma.
> + String[] tokens = str.split(",");
> + ArrayList<String> l = new ArrayList<>(tokens.length);
> + for (String s : tokens) {
> + if (!s.isEmpty() && !l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + l.trimToSize();
> + return l;
> + }
> +
> + // Parse string that consists of token delimited by comma
> + // 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) {
> + // String is delimited by comma
> + String[] tokens = str.split(",");
> + ArrayList<String> l = new ArrayList<>(tokens.length);
> +
> + for (String s : tokens) {
> + if (!s.isEmpty()) {
> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
> + // Not BSD style
> + s = '[' + s + ']';
> + }
> + if (!s.isEmpty() && !l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + l.trimToSize();
> + return l;
> }
>
> // Load DNS configuration from OS
> @@ -81,28 +107,34 @@ 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 {
> - if (lastRefresh >= 0) {
> - long currTime = System.currentTimeMillis();
> - if ((currTime - lastRefresh) < TIMEOUT) {
> - return;
> - }
> + // Otherwise we refresh if TIMEOUT_NANOS has passed
> since last
> + // load.
> + long currTime = System.nanoTime();
> + // lastRefresh will always have been set once because
> we start with
> + // changed = true.
> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
> + return;
> }
> }
>
> - // load DNS configuration, update timestamp, create
> - // new HashMaps from the loaded configuration
> - //
> + // Native code that uses Windows API to find out the DNS
> server
> + // addresses and search suffixes. It builds a
> comma-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.
> loadDNSconfig0();
>
> - 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..e830b8e70b 100644
> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All
> rights reserved.
> + * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All
> rights reserved.
> * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
> *
> * This code is free software; you can redistribute it and/or
> modify it
> @@ -24,17 +24,15 @@
> */
>
> #include <stdlib.h>
> -#include <windows.h>
> #include <stdio.h>
> #include <stddef.h>
> -#include <iprtrmib.h>
> #include <time.h>
> #include <assert.h>
> -#include <iphlpapi.h>
>
> +#include "net_util.h"
> #include "jni_util.h"
>
> -#define MAX_STR_LEN 256
> +#define MAX_STR_LEN 1024
>
> #define STS_NO_CONFIG 0x0 /* no configuration
> found */
> #define STS_SL_FOUND 0x1 /* search list found */
> @@ -48,9 +46,11 @@
> 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"
> + * Utility routine to append s2 to s1 with a comma delimiter.
> + * strappend(s1="abc", "def") => "abc,def"
> * strappend(s1="", "def") => "def
> */
> void strappend(char *s1, char *s2) {
> @@ -60,41 +60,32 @@ void strappend(char *s1, char *s2) {
> return;
>
> len = strlen(s1)+1;
> - if (s1[0] != 0) /* needs space
> character */
> + if (s1[0] != 0) /* needs comma
> character */
> len++;
> if (len + strlen(s2) > MAX_STR_LEN) /* insufficient space */
> return;
>
> if (s1[0] != 0) {
> - strcat(s1, " ");
> + strcat(s1, ",");
> }
> strcat(s1, 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;
> + WCHAR *suffix;
> + DWORD ret, flags;
> DWORD dwLen;
> ULONG ulType;
> char result[MAX_STR_LEN];
> HANDLE hKey;
> - int gotSearchList = 0;
> + SOCKADDR *sockAddr;
> + struct sockaddr_in6 *sockAddrIpv6;
>
> /*
> * First see if there is a global suffix list specified.
> @@ -112,128 +103,74 @@ 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);
> + adapter = adapters;
> + while (adapter != NULL) {
> + // Only load config from enabled adapters.
> + if (adapter->OperStatus == IfOperStatusUp) {
> + dnsServer = adapter->FirstDnsServerAddress;
> + while (dnsServer != NULL) {
> + sockAddr = dnsServer->Address.lpSockaddr;
> + if (sockAddr->sa_family == AF_INET6) {
> + sockAddrIpv6 = (struct sockaddr_in6 *)sockAddr;
> + if (sockAddrIpv6->sin6_scope_id != 0) {
> + // An address with a scope is either
> link-local or
> + // site-local, which aren't valid for DNS
> queries so
> + // we can skip them.
> + dnsServer = dnsServer->Next;
> + continue;
> }
> }
>
> - /*
> - * 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';
> 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(sockAddr,
> + 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->DnsSuffix;
> + if (suffix != NULL) {
> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix, -1,
> + result, sizeof(result), NULL, NULL);
> + if (ret != 0) {
> + strappend(sl, result);
> + }
> + }
> }
> - }
>
> - /*
> - * Free the adpater structure
> - */
> - if (adapterP) {
> - free(adapterP);
> + adapter = adapter->Next;
> }
>
> + free(adapters);
> +
> return STS_SL_FOUND & STS_NS_FOUND;
> }
>
>
> /*
> - * Initialize JNI field IDs.
> + * Initialize JNI field IDs and classes.
> */
> JNIEXPORT void JNICALL
> Java_sun_net_dns_ResolverConfigurationImpl_init0(JNIEnv *env,
> jclass cls)
> @@ -260,7 +197,7 @@
> 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
> @@ -272,8 +209,6 @@
> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv
> *env, jclass cl
> obj = (*env)->NewStringUTF(env, nameservers);
> CHECK_NULL(obj);
> (*env)->SetStaticObjectField(env, cls, nameserversID, obj);
> - } else {
> - JNU_ThrowOutOfMemoryError(env, "native memory allocation
> failed");
> }
> }
>
>
>
> best regards,
>
> -- daniel
>
>
> On 09/01/2020 00:54, Aleks Efimov wrote:
> > Got the testing results: the CI is happy with the last patch
> - no JNDI
> > test failures observed
> >
> > Kind Regards,
> > Aleksei
>
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