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
<e...@zusammenkunft.net <mailto:e...@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-boun...@openjdk.java.net
<mailto:net-dev-boun...@openjdk.java.net>> im Auftrag von Anuraag
Agrawal <anura...@gmail.com <mailto:anura...@gmail.com>>
*Gesendet:* Sonntag, November 24, 2019 10:47 AM
*An:* net-dev@openjdk.java.net <mailto:net-dev@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
