Heartbeat extension kills connections on Android
The Android NDK's macro definitions for ICMP6 filters are wrong.
This causes the Heartbeat extension to not catch ICMP6_ECHO_REPLY
messages and makes it consider the connection stale. Once it has
missed enough of the messages, it will try to recover it with
UPDATE messages, and as it still doesn't see the replies, it will
eventually remove the SA of the supposedly dead connection.
Redefining the filters fixes the issue. A fix has been committed;
adding this bug report for consistency.