[PATCH] 7006496: Use modern Windows API to retrieve OS DNS servers
Anuraag Agrawal
anuraaga at gmail.com
Tue Dec 10 06:59:04 UTC 2019
Hi Aleksei,
Thanks for running the test. I had checked the global search list, but
realize I didn't check connection-specific suffixes which were causing the
issue you see. While the documentation states that FirstDnsSuffix is
populated on Vista+, amazingly it doesn't seem to be
https://docs.microsoft.com/en-us/windows/win32/api/iptypes/ns-iptypes-ip_adapter_addresses_lh
Chromium has run into the same issue and just doesn't use the field
https://cs.chromium.org/chromium/src/net/dns/dns_config_service_win.cc?q=firstdnssuffix&sq=package:chromium&dr=C&l=532
So I have gone ahead and switched to using the normal DnsSuffix field.
DnsSuffix and looking up the search list in the registry should generally
give a full list.
During this testing, other issues I found are that the search list returns
a comma-separated list. So to keep the string list parsing simple, I
changed the delimiter from space to comma. Also, on my machine I would
always have DNS servers like fec0:0:0:ffff:1 on some adapters. At first, I
assumed it is ok to return these, since they are configured by the OS and
should be valid, but I learnt that these are deprecated IPv6 site-local
addresses and should not be used.
https://en.wikipedia.org/wiki/Unique_local_address
I used the same check for site-local as Inet6Address, which just sees if
the first bytes are fec0.
Thanks again - 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..b9a06461ab 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.
@@ -50,30 +50,65 @@ 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;
-
- // 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 (!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) {
+ // IPv6
+ if (s.charAt(0) != '[') {
+ // Not BSD style
+ s = '[' + s + ']';
+ }
+ if (s.startsWith("[fec0:")) {
+ // Deprecated site-local address. Windows adds
+ // such addresses to IPv6 adapters without DNS
+ // configured, but these should not actually be
+ // used for queries.
+ continue;
+ }
+ }
+ if (!l.contains(s)) {
+ l.add(s);
+ }
+ }
+ }
+ l.trimToSize();
+ return l;
}
// Load DNS configuration from OS
@@ -81,28 +116,34 @@ 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 {
+ // 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
- //
+ // 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..427d7c85eb 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
@@ -30,6 +30,7 @@
#include <iprtrmib.h>
#include <time.h>
#include <assert.h>
+#include <winsock2.h>
#include <iphlpapi.h>
#include "jni_util.h"
@@ -48,8 +49,10 @@
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.
+ * Utility routine to append s2 to s1 with a comma delimiter.
* strappend(s1="abc", "def") => "abc def"
* strappend(s1="", "def") => "def
*/
@@ -60,41 +63,30 @@ 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;
/*
* First see if there is a global suffix list specified.
@@ -112,122 +104,55 @@ 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) {
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->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;
}
@@ -260,7 +185,7 @@
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 Tue, Dec 10, 2019 at 1:29 AM Aleks Efimov <aleksej.efimov at oracle.com>
wrote:
> Hi Anuraag,
>
> The webrev with your latest changes can be found here:
> http://cr.openjdk.java.net/~aefimov/anuraaga/7006496/01
>
> The copyright changes looks good.
>
> The split by space also looks good with assumption that we will never get
> string with two spaces between IP addresses/DNS suffixes.
>
> I've also performed one test on Windows machine and it shows an issue with
> the retrieval of DNS suffixes:
> Method to call:
> sun.net.dns.ResolverConfiguration.open().searchlist()
>
> Old implementation returns:
> [test.domain.com]
>
> With the latest patch the suffixes list (searchlist) is empty:
> []
>
> I've collected the following information on the test host that might help
> you to fix the issue:
>
> The host OS: Microsoft Windows Server 2016 Standard
>
> Networking configuration (<---> is for masked addresses/info):
> $ ipconfig /all
>
> Windows IP Configuration
>
> Host Name . . . . . . . . . . . . : host-name-1
> Primary Dns Suffix . . . . . . . :
> Node Type . . . . . . . . . . . . : Hybrid
> IP Routing Enabled. . . . . . . . : No
> WINS Proxy Enabled. . . . . . . . : No
> DNS Suffix Search List. . . . . . : test.domain.com
>
> Ethernet adapter Ethernet:
>
> Connection-specific DNS Suffix . : test.domain.com
> Description . . . . . . . . . . . : Broadcom NetXtreme-E Virtual
> Function
> Physical Address. . . . . . . . . : <------------>
> DHCP Enabled. . . . . . . . . . . : Yes
> Autoconfiguration Enabled . . . . : Yes
> Link-local IPv6 Address . . . . . : <------------>
> IPv4 Address. . . . . . . . . . . : <------------>
> Subnet Mask . . . . . . . . . . . : <------------>
> Lease Obtained. . . . . . . . . . : <------------>
> Lease Expires . . . . . . . . . . : <------------>
> Default Gateway . . . . . . . . . : <------------>
> DHCP Server . . . . . . . . . . . : <------------>
> DHCPv6 Client DUID. . . . . . . . : <------------>
> DNS Servers . . . . . . . . . . . : <------------>
> <------------>
> NetBIOS over Tcpip. . . . . . . . : Disabled
>
> Tunnel adapter isatap.test.domain.com:
>
> Media State . . . . . . . . . . . : Media disconnected
> Connection-specific DNS Suffix . : test.domain.com
> Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
> Physical Address. . . . . . . . . : <------------>
> DHCP Enabled. . . . . . . . . . . : No
> Autoconfiguration Enabled . . . . : Yes
>
>
> - Aleksei
>
>
> On 07/12/2019 09:44, Anuraag Agrawal wrote:
>
> Hi all,
>
> Thanks for the reviews. I've fixed the formatting errors, and I hope I
> fixed the copyright issue. I couldn't find documentation on the format of
> the copyright header, but assume the second number is the year of
> modification to update. I found ResolverConfigurationImpl.c to have an old
> one and updated it to 2019.
>
> I also found the note in the docs that StringTokenizer is deprecated and
> shouldn't be used - I agree it's a good time to replace it. As we have a
> simple split by space, I have gone ahead and used the simpler String.split
> instead of regex, hope that makes sense. While in many code I'd be a little
> concerned with the array allocation, this is only run very infrequently so
> I think it should be ok.
>
> Inline diff 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..47065e805e 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.
> @@ -50,30 +50,55 @@ 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;
> -
> - // 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 space
> + // 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 space.
> + String[] tokens = str.split(" ");
> + ArrayList<String> l = new ArrayList<>(tokens.length);
> + for (String s : tokens) {
> + if (!l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + l.trimToSize();
> + 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) {
> + // String is delimited by space
> + 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 (!l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + l.trimToSize();
> + return l;
> }
>
> // Load DNS configuration from OS
> @@ -81,28 +106,34 @@ 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 {
> + // 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
> - //
> + // 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.
> 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..85a7935314 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
> @@ -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 Sat, Dec 7, 2019 at 12:41 AM Alan Bateman <Alan.Bateman at oracle.com>
> wrote:
>
>> On 06/12/2019 15:34, Aleks Efimov wrote:
>> > :
>> >
>> > I've created webrev with your latest changes - it could be convenient
>> > for other reviewers:
>> > http://cr.openjdk.java.net/~aefimov/anuraaga/7006496/00
>> >
>> > I will happily sponsor this change once it gets necessary approvals
>> This could be split into two issues but since the code using
>> StringTokenizer is changing significantly then we should replace it with
>> regex while we there.
>>
>> -Alan
>>
>
>
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