From 969d82bc82db2ab4912ae9fdbb85066a6d403d3c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>
Date: Wed, 19 Mar 2025 16:33:05 -0700
Subject: [PATCH] LocalNetAccessKey - improve toString
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while at it, improve dump to clarify default is true meaning global,
even though you could assume 0/false is the default, and that true means local...

  $ adb shell dumpsys connectivity trafficcontroller </dev/null | grep LocalNetAccess
Before on bluejay (47 is wlan0, 51 is v4-wlan0):
  sLocalNetAccessMap:
    LocalNetAccessKey{lpmBitlen=132, ifIndex=47, remoteAddress=/::ffff:224.0.0.0, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=160, ifIndex=47, remoteAddress=/::ffff:255.255.255.255, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=96, ifIndex=47, remoteAddress=/2a00:79e1:2e00:3f01::, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=96, ifIndex=47, remoteAddress=/fe80::, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=40, ifIndex=47, remoteAddress=/ff00::, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=132, ifIndex=51, remoteAddress=/::ffff:224.0.0.0, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=160, ifIndex=51, remoteAddress=/::ffff:255.255.255.255, protocol=0, remotePort=0}: false
    LocalNetAccessKey{lpmBitlen=40, ifIndex=51, remoteAddress=/ff00::, protocol=0, remotePort=0}: false
After this commit:
  sLocalNetAccessMap (default is true meaning global):
    LocalNetAccessKey{lpmBitlen=132 ifIndex=47 remoteAddress=224.0.0.0/4}: false
    LocalNetAccessKey{lpmBitlen=160 ifIndex=47 remoteAddress=255.255.255.255}: false
    LocalNetAccessKey{lpmBitlen=96 ifIndex=47 remoteAddress=2a00:79e1:2e00:3f01::/64}: false
    LocalNetAccessKey{lpmBitlen=96 ifIndex=47 remoteAddress=fe80::/64}: false
    LocalNetAccessKey{lpmBitlen=40 ifIndex=47 remoteAddress=ff00::/8}: false
    LocalNetAccessKey{lpmBitlen=132 ifIndex=51 remoteAddress=224.0.0.0/4}: false
    LocalNetAccessKey{lpmBitlen=160 ifIndex=51 remoteAddress=255.255.255.255}: false
    LocalNetAccessKey{lpmBitlen=40 ifIndex=51 remoteAddress=ff00::/8}: false

On cuttlefish (15 is buried_eth0, 17 is wlan0):
  sLocalNetAccessMap (default is true meaning global):
    LocalNetAccessKey{lpmBitlen=144 ifIndex=15 remoteAddress=192.168.0.0/16}: false
    LocalNetAccessKey{lpmBitlen=132 ifIndex=15 remoteAddress=224.0.0.0/4}: false
    LocalNetAccessKey{lpmBitlen=160 ifIndex=15 remoteAddress=255.255.255.255}: false
    LocalNetAccessKey{lpmBitlen=40 ifIndex=15 remoteAddress=ff00::/8}: false
    LocalNetAccessKey{lpmBitlen=192 ifIndex=17 remoteAddress=192.168.99.1 protocol=6 remotePort=53}: true
    LocalNetAccessKey{lpmBitlen=192 ifIndex=17 remoteAddress=192.168.99.1 protocol=17 remotePort=53}: true
    LocalNetAccessKey{lpmBitlen=144 ifIndex=17 remoteAddress=192.168.0.0/16}: false
    LocalNetAccessKey{lpmBitlen=132 ifIndex=17 remoteAddress=224.0.0.0/4}: false
    LocalNetAccessKey{lpmBitlen=160 ifIndex=17 remoteAddress=255.255.255.255}: false
    LocalNetAccessKey{lpmBitlen=96 ifIndex=17 remoteAddress=fe80::/64}: false
    LocalNetAccessKey{lpmBitlen=40 ifIndex=17 remoteAddress=ff00::/8}: false

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ifcebc18c3804bc1d5d705752021bb4643ed58eb5
---
 .../module/util/bpf/LocalNetAccessKey.java    | 48 ++++++++++++++++---
 .../src/com/android/server/BpfNetMaps.java    |  2 +-
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/common/src/com/android/net/module/util/bpf/LocalNetAccessKey.java b/common/src/com/android/net/module/util/bpf/LocalNetAccessKey.java
index 95265b9744..48e8b067f3 100644
--- a/common/src/com/android/net/module/util/bpf/LocalNetAccessKey.java
+++ b/common/src/com/android/net/module/util/bpf/LocalNetAccessKey.java
@@ -61,12 +61,46 @@ public class LocalNetAccessKey extends Struct {
 
     @Override
     public String toString() {
-        return "LocalNetAccessKey{"
-                + "lpmBitlen=" + lpmBitlen
-                + ", ifIndex=" + ifIndex
-                + ", remoteAddress=" + remoteAddress
-                + ", protocol=" + protocol
-                + ", remotePort=" + remotePort
-                + "}";
+        String s = "LocalNetAccessKey{lpmBitlen=" + lpmBitlen;
+
+        long bits = lpmBitlen;
+
+        // u32 ifIndex
+        if (bits <= 0 && ifIndex != 0) s += " ??";
+        if (bits > 0 || ifIndex != 0) s += " ifIndex=" + ifIndex;
+        if (bits > 0 && bits < 32) s += "/" + bits + "[LE]";
+        bits -= 32;
+
+        // u128 remoteAddress
+        if (bits <= 0 && !remoteAddress.isAnyLocalAddress()) s += " ??";
+        if (bits > 0 || !remoteAddress.isAnyLocalAddress()) {
+            s += " remoteAddress=";
+            String ip = remoteAddress.toString();
+            if (ip.startsWith("/::ffff:")) { // technically wrong IPv4-mapped IPv6 address detection
+              s += ip.substring(8);
+              if (bits >= 96 && bits < 128) s += "/" + (bits - 96);
+            } else if (ip.startsWith("/")) {
+              s += ip.substring(1);
+              if (bits >= 0 && bits < 128) s += "/" + bits;
+            } else { // WTF, includes a hostname or what?
+              s += ip;
+            }
+        }
+        bits -= 128;
+
+        // u16 protocol
+        if (bits <= 0 && protocol != 0) s += " ??";
+        if (bits > 0 || protocol != 0) s += " protocol=" + protocol;
+        if (bits > 0 && bits < 16) s += "/" + bits + "[LE16]";
+        bits -= 16;
+
+        // be16 remotePort
+        if (bits <= 0 && remotePort != 0) s += " ??";
+        if (bits > 0 || remotePort != 0) s += " remotePort=" + remotePort;
+        if (bits > 0 && bits < 16) s += "/" + bits + "[BE16]";
+        bits -= 16;
+
+        s += "}";
+        return s;
     }
 }
diff --git a/service/src/com/android/server/BpfNetMaps.java b/service/src/com/android/server/BpfNetMaps.java
index 9bd407dfd2..523ffee216 100644
--- a/service/src/com/android/server/BpfNetMaps.java
+++ b/service/src/com/android/server/BpfNetMaps.java
@@ -1327,7 +1327,7 @@ public class BpfNetMaps {
                             + value.iif1 + "(" + mDeps.getIfName(value.iif1) + "), "
                             + value.iif2 + "(" + mDeps.getIfName(value.iif2) + ")");
             if (sLocalNetBlockedUidMap != null) {
-                BpfDump.dumpMap(sLocalNetAccessMap, pw, "sLocalNetAccessMap",
+                BpfDump.dumpMap(sLocalNetAccessMap, pw, "sLocalNetAccessMap (default is true meaning global)",
                         (key, value) -> "" + key + ": " + value.val);
             }
             if (sLocalNetBlockedUidMap != null) {