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CLI: Add sdns stamp decoder

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to assist in DoH server list maintenance
This commit is contained in:
zzz
2024-01-31 08:29:20 -05:00
parent bdaa9b1be9
commit 3922795f9c
1 changed files with 145 additions and 2 deletions
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147
core/java/src/net/i2p/util/DNSOverHTTPS.java
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@@ -2,6 +2,7 @@ package net.i2p.util;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
@@ -535,8 +536,10 @@ public class DNSOverHTTPS implements EepGet.StatusListener {
Type type = Type.V4_ONLY;
boolean error = false;
boolean testall = false;
boolean decode = false;
boolean process = false;
String url = null;
Getopt g = new Getopt("dnsoverhttps", args, "46fstu:");
Getopt g = new Getopt("dnsoverhttps", args, "46fstu:dp");
try {
int c;
while ((c = g.getopt()) != -1) {
@@ -549,10 +552,24 @@ public class DNSOverHTTPS implements EepGet.StatusListener {
type = Type.V6_ONLY;
break;
case 'd':
if (decode || process || testall)
error = true;
else
decode = true;
break;
case 'f':
type = Type.V4_PREFERRED;
break;
case 'p':
if (decode || process || testall)
error = true;
else
process = true;
break;
case 's':
type = Type.V6_PREFERRED;
break;
@@ -613,6 +630,14 @@ public class DNSOverHTTPS implements EepGet.StatusListener {
clearCaches();
}
System.out.println("Test complete: " + pass + " pass, " + fail + " fail");
} else if (decode) {
decodeStamp(hostname, true);
} else if (process) {
try {
decodeStamps(hostname);
} catch (IOException ioe) {
ioe.printStackTrace();
}
} else {
String result = (new DNSOverHTTPS(I2PAppContext.getGlobalContext())).lookup(hostname, type, url);
if (result != null)
@@ -629,6 +654,124 @@ public class DNSOverHTTPS implements EepGet.StatusListener {
" [-t] (test all servers)\n" +
" [-u 'https://host/dns-query?...&'] (request from this URL only)\n" +
" [-4] (IPv4 only) (default)\n" +
" [-6] (IPv6 only)");
" [-6] (IPv6 only)\n" +
"DNSOverHTTPS -d sdns://... (decode server stamp)\n" +
"DNSOverHTTPS -p doh-resolvers.md (decode all server stamps in file)");
}
/**
* Decode sdns:// stamps
* e.g. sdns://AgMAAAAAAAAADjE2My40Ny4xMTcuMTc2oMwQYNOcgym2K2-8fQ1t-TCYabmB5-Y5LVzY-kCPTYDmIEROvWe7g_iAezkh6TiskXi4gr1QqtsRIx8ETPXwjffOEGFkbC5hZGZpbHRlci5uZXQKL2Rucy1xdWVyeQ
* Ref: https://dnscrypt.info/stamps-specifications/
*
* @return the URL, or null on error or if not a DoH (type 2) stamp
* @since 0.9.62
*/
private static String decodeStamp(String sdns, boolean log) {
byte[] d = null;
try {
if (!sdns.startsWith("sdns://")) {
if (log) System.out.println("Must start with sdns://");
return null;
}
sdns = sdns.substring(7);
sdns = sdns.replace("_", "~");
d = Base64.decode(sdns);
if (d == null) {
if (log) System.out.println("Bad encoding");
return null;
}
int type = d[0] & 0xff;
// little endian, ignore last 7 bytes
int props = d[1] & 0xff;
int len = d[9] & 0xff;
String addr = "n/a";
if (len > 0) {
try {
addr = new String(d, 10, len, "ISO-8859-1");
} catch (IOException ioe) {}
}
String host = "";
String path = "/";
if (type == 0x02) {
int off = 10 + len;
int vlen = d[off++] & 0xff;
// skip VLP of hashes
while ((vlen & 0x80) != 0) {
off += vlen & 0x7f;
vlen = d[off++] & 0xff;
}
off += vlen;
len = d[off++] & 0xff;
if (len > 0) {
try {
host = new String(d, off, len, "ISO-8859-1");
} catch (IOException ioe) {}
off += len;
}
len = d[off++] & 0xff;
if (len > 0) {
try {
path = new String(d, off, len, "ISO-8859-1");
} catch (IOException ioe) {}
off += len;
}
}
String url = (type == 2 && host.length() > 0) ? "https://" + host + path : null;
if (log) {
if (url != null)
System.out.print(url + ' ');
if (type == 1)
System.out.print("DNSCrypt");
else if (type == 2)
System.out.print("DoH");
else if (type == 3)
System.out.print("DNSoverTLS");
else if (type == 4)
System.out.print("DNSoverQUIC");
else if (type == 5)
System.out.print("oDoH");
else if (type == 0x81)
System.out.print("DNSCrypt-relay");
else if (type == 0x85)
System.out.print("oDoH-relay");
else
System.out.print("unknown-" + type);
System.out.println(" logs? " + ((props & 0x01) == 0) +
" filters? " + ((props & 0x02) == 0) +
" IP: " + addr);
}
return url;
} catch (IndexOutOfBoundsException ioobe) {
if (log) {
System.out.println("Failed: " + ioobe);
//ioobe.printStackTrace();
System.out.println(HexDump.dump(d));
}
return null;
}
}
/**
* Decode sdns:// stamps found in file
*
* @return the URL, or null on error or if not a DoH (type 2) stamp
* @since 0.9.62
*/
private static void decodeStamps(String file) throws IOException {
BufferedReader in = null;
try {
FileInputStream fis = new FileInputStream(file);
in = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
String line = null;
while ( (line = in.readLine()) != null) {
line = line.trim();
if (!line.startsWith("sdns://"))
continue;
decodeStamp(line, true);
}
} finally {
if (in != null) try { in.close(); } catch (IOException ioe) {}
}
}
}