com.couchbase.client.core.deps.org.xbill.DNS.ClientSubnetOption Maven / Gradle / Ivy
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// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) 1999-2004 Brian Wellington ([email protected])
package com.couchbase.client.core.deps.org.xbill.DNS;
import java.net.InetAddress;
import java.net.UnknownHostException;
/**
* The Client Subnet EDNS Option, defined in Client
* subnet in DNS requests.
*
* The option is used to convey information about the IP address of the originating client, so
* that an authoritative server can make decisions based on this address, rather than the address of
* the intermediate caching name server.
*
*
The option is transmitted as part of an OPTRecord in the additional section of a DNS message,
* as defined by RFC 6891 (EDNS0).
*
*
The wire format of the option contains a 2-byte length field (1 for IPv4, 2 for IPv6), a
* 1-byte source netmask, a 1-byte scope netmask, and an address truncated to the source netmask
* length (where the final octet is padded with bits set to 0)
*
* @see OPTRecord
* @author Brian Wellington
* @author Ming Zhou <[email protected]>, Beaumaris Networks
*/
public class ClientSubnetOption extends EDNSOption {
private int family;
private int sourcePrefixLength;
private int scopePrefixLength;
private InetAddress address;
ClientSubnetOption() {
super(EDNSOption.Code.CLIENT_SUBNET);
}
private static int checkMaskLength(String field, int family, int val) {
int max = Address.addressLength(family) * 8;
if (val < 0 || val > max) {
throw new IllegalArgumentException(
"\"" + field + "\" " + val + " must be in the range [0.." + max + "]");
}
return val;
}
/**
* Construct a Client Subnet option. Note that the number of significant bits in the address must
* not be greater than the supplied source netmask. There may also be issues related to Java's
* handling of mapped addresses
*
* @param sourcePrefixLength The length of the netmask pertaining to the query. In replies, it
* mirrors the same value as in the requests.
* @param scopePrefixLength The length of the netmask pertaining to the reply. In requests, it
* MUST be set to 0. In responses, this may or may not match the source netmask.
* @param address The address of the client.
*/
public ClientSubnetOption(int sourcePrefixLength, int scopePrefixLength, InetAddress address) {
super(EDNSOption.Code.CLIENT_SUBNET);
this.family = Address.familyOf(address);
this.sourcePrefixLength = checkMaskLength("source netmask", this.family, sourcePrefixLength);
this.scopePrefixLength = checkMaskLength("scope netmask", this.family, scopePrefixLength);
this.address = Address.truncate(address, sourcePrefixLength);
if (!address.equals(this.address)) {
throw new IllegalArgumentException("source netmask is not valid for address");
}
}
/**
* Construct a Client Subnet option with scope netmask set to 0.
*
* @param sourcePrefixLength The length of the netmask pertaining to the query. In replies, it
* mirrors the same value as in the requests.
* @param address The address of the client.
* @see ClientSubnetOption
*/
public ClientSubnetOption(int sourcePrefixLength, InetAddress address) {
this(sourcePrefixLength, 0, address);
}
/** Returns the family of the network address. This will be either IPv4 (1) or IPv6 (2). */
public int getFamily() {
return family;
}
/** Returns the source netmask. */
public int getSourcePrefixLength() {
return sourcePrefixLength;
}
/** Returns the scope netmask. */
public int getScopePrefixLength() {
return scopePrefixLength;
}
/** Returns the IP address of the client. */
public InetAddress getAddress() {
return address;
}
@Override
void optionFromWire(DNSInput in) throws WireParseException {
family = in.readU16();
if (family != Address.IPv4 && family != Address.IPv6) {
throw new WireParseException("unknown address family");
}
sourcePrefixLength = in.readU8();
if (sourcePrefixLength > Address.addressLength(family) * 8) {
throw new WireParseException("invalid source netmask");
}
scopePrefixLength = in.readU8();
if (scopePrefixLength > Address.addressLength(family) * 8) {
throw new WireParseException("invalid scope netmask");
}
// Read the truncated address
byte[] addr = in.readByteArray();
if (addr.length != (sourcePrefixLength + 7) / 8) {
throw new WireParseException("invalid address");
}
// Convert it to a full length address.
byte[] fulladdr = new byte[Address.addressLength(family)];
System.arraycopy(addr, 0, fulladdr, 0, addr.length);
try {
address = InetAddress.getByAddress(fulladdr);
} catch (UnknownHostException e) {
throw new WireParseException("invalid address", e);
}
InetAddress tmp = Address.truncate(address, sourcePrefixLength);
if (!tmp.equals(address)) {
throw new WireParseException("invalid padding");
}
}
@Override
void optionToWire(DNSOutput out) {
out.writeU16(family);
out.writeU8(sourcePrefixLength);
out.writeU8(scopePrefixLength);
out.writeByteArray(address.getAddress(), 0, (sourcePrefixLength + 7) / 8);
}
@Override
String optionToString() {
StringBuilder sb = new StringBuilder();
sb.append(address.getHostAddress());
sb.append("/");
sb.append(sourcePrefixLength);
sb.append(", scope netmask ");
sb.append(scopePrefixLength);
return sb.toString();
}
}