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Util: Roll our own IPv4 address parsing

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to avoid InetAddress.getByName() calls
May help high CPU usage on Windows?
Reported by parg: http://zzz.i2p/topics/3083
More empty hostname checks
This commit is contained in:
zzz
2021-03-15 07:41:02 -04:00
parent be863d643e
commit a1340d8796
1 changed files with 43 additions and 6 deletions
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49
core/java/src/net/i2p/util/Addresses.java
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@@ -478,12 +478,15 @@ public abstract class Addresses {
* Unlike InetAddress.getByName(), we do NOT allow numeric IPs
* of the form d.d.d, d.d, or d, as these are almost certainly mistakes.
*
* InetAddress.getByName() also returns 127.0.0.1 for a host "",
* but this is undocumented; as of 0.9.50, here we return null.
*
* @param host literal IPv4 or IPv6 address; if null returns null
* @return IP or null
* @since 0.9.32
*/
public static byte[] getIPOnly(String host) {
if (host == null)
if (host == null || host.isEmpty())
return null;
byte[] rv;
synchronized (_IPAddress) {
@@ -492,7 +495,13 @@ public abstract class Addresses {
if (rv == null) {
if (isIPAddress(host)) {
try {
rv = InetAddress.getByName(host).getAddress();
if (host.contains(".")) {
rv = getIPv4(host);
if (rv == null)
return null;
} else {
rv = InetAddress.getByName(host).getAddress();
}
synchronized (_IPAddress) {
_IPAddress.put(host, rv);
}
@@ -510,12 +519,15 @@ public abstract class Addresses {
* else the other type if available.
* Will resolve but not cache DNS hostnames.
*
* InetAddress.getByName() also returns 127.0.0.1 for a host "",
* but this is undocumented; as of 0.9.50, here we return null.
*
* @param host DNS or IPv4 or IPv6 address; if null returns null
* @return IP or null
* @since 0.9.28
*/
public static byte[] getIP(String host, boolean preferIPv6) {
if (host == null)
if (host == null || host.isEmpty())
return null;
if (isIPAddress(host))
return getIP(host);
@@ -563,12 +575,15 @@ public abstract class Addresses {
* Number of results may also change based on caching at various layers,
* even if the ultimate name server results did not change.
*
* InetAddress.getByName() also returns 127.0.0.1 for a host "",
* but this is undocumented; as of 0.9.50, here we return null.
*
* @param host DNS or IPv4 or IPv6 address; if null returns null
* @return non-empty list IPs, or null if none
* @since 0.9.28
*/
public static List<byte[]> getIPs(String host) {
if (host == null)
if (host == null || host.isEmpty())
return null;
if (isIPAddress(host)) {
byte[] brv = getIP(host);
@@ -623,8 +638,30 @@ public abstract class Addresses {
return InetAddressUtils.isIPv4Address(host) || InetAddressUtils.isIPv6Address(host);
}
/**
* Because InetAddress.getByName() is slow, esp. on Windows
*
* @param host w.x.y.z only
* @return 4 bytes or null
* @since 0.9.50
*/
private static byte[] getIPv4(String host) {
String[] s = DataHelper.split(host, "\\.", 4);
if (s.length != 4)
return null;
byte[] rv = new byte[4];
try {
for (int i = 0; i < 4; i++) {
int b = Integer.parseInt(s[i]);
if (b < 0 || b > 255)
return null;
rv[i] = (byte) b;
}
} catch (NumberFormatException nfe) {
return null;
}
return rv;
}
//////// IPv6 Cache Utils ///////