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SSU: Fallback processing for MTU detection

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take the minimum of all interfaces if specific interface not found
Update CLI to support address args for testing
This commit is contained in:
zzz
2022-09-07 10:00:42 -04:00
parent f00e020f2b
commit 26f882edd5
1 changed files with 69 additions and 9 deletions
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78
router/java/src/net/i2p/router/transport/udp/MTU.java
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@@ -4,7 +4,9 @@ import java.net.InetAddress;
import java.net.Inet6Address;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import net.i2p.I2PAppContext;
import net.i2p.util.Log;
@@ -60,6 +62,8 @@ public class MTU {
return 0;
}
if (ifcs != null) {
// save for fallback loop below, so we don't have to call getNetworkInterfaces() again
List<NetworkInterface> interfaces = new ArrayList<NetworkInterface>();
while (ifcs.hasMoreElements()) {
NetworkInterface ifc = ifcs.nextElement();
try {
@@ -72,6 +76,7 @@ public class MTU {
} catch (SocketException e) {
continue;
}
interfaces.add(ifc);
for(Enumeration<InetAddress> addrs = ifc.getInetAddresses(); addrs.hasMoreElements();) {
InetAddress addr = addrs.nextElement();
if (ia.equals(addr)) {
@@ -120,6 +125,59 @@ public class MTU {
}
}
}
// didn't find a match, probably behind a NAT
// try again, looping through all the interfaces that were up,
// just get the minimum of all interfaces with addresses of that type v4/v6
boolean isIPv6 = ia instanceof Inet6Address;
int rv = 1501;
outer:
for (NetworkInterface ifc : interfaces) {
for(Enumeration<InetAddress> addrs = ifc.getInetAddresses(); addrs.hasMoreElements();) {
InetAddress addr = addrs.nextElement();
if (isIPv6 != (addr instanceof Inet6Address))
continue;
if (addr.isLinkLocalAddress() ||
addr.isMulticastAddress() ||
addr.isAnyLocalAddress() ||
addr.isLoopbackAddress())
continue;
if (isIPv6) {
// ygg
byte[] ip = addr.getAddress();
if ((ip[0] & 0xfe) == 0x02)
continue outer;
}
int mtu;
try {
mtu = ifc.getMTU();
} catch (Throwable t) {
continue outer;
}
if (mtu < 0)
continue outer;
if (isIPv6 && mtu > 1420) {
byte[] ip = addr.getAddress();
if (mtu > 1472 &&
ip[0] == 0x20 && ip[1] == 0x01 &&
ip[2] == 0x04 && ip[3] == 0x70)
mtu = 1472;
if (ip[0] == 0x2a && ip[1] == 0x06 &&
ip[2] == (byte) 0xa0 && ip[3] == 0x04)
mtu = 1420;
}
if (mtu < rv)
rv = mtu;
continue outer;
}
}
if (rv < 1501) {
if (isSSU2)
return rv;
if (rv == PeerState2.MIN_MTU)
return rv;
return rectify(isIPv6, rv);
}
}
return 0;
}
@@ -144,18 +202,20 @@ public class MTU {
}
public static void main(String args[]) {
/****
System.out.println("Cmd line interfaces:");
for (int i = 0; i < args.length; i++) {
try {
InetAddress test = InetAddress.getByName(args[i]);
System.out.println("MTU of " + args[i] + " is " + getMTU(test));
} catch (Exception e) {
e.printStackTrace();
if (args.length > 0) {
System.out.println("Cmd line interfaces:");
for (int i = 0; i < args.length; i++) {
try {
InetAddress test = InetAddress.getByName(args[i]);
System.out.println("I2P MTU of " + args[i] + " is " + getMTU(test, false) +
"; SSU2 MTU is " + getMTU(test, true));
} catch (Exception e) {
e.printStackTrace();
}
}
}
System.out.println("All interfaces:");
****/
try {
Enumeration<NetworkInterface> ifcs = NetworkInterface.getNetworkInterfaces();
if (ifcs != null) {