+152
−104
Loading
Improvements to netlink event parsing.
1. Accept that parseNetlinkMessage can only parse one netlink
message, because its way of returning output is to modify its
member variables (mAction, mParams, etc.). Currently, it
loops through all the messages it finds, updating its member
variables as it goes along, and always returns true at the end
of the buffer. This has the following problems:
1. Since the function always returns true even when no
messages were parsed, the caller has no way to know if
parsing succeeded, and we get lots of "No subsystem found
in netlink event" logs if the buffer did not contain any
valid messages we were interested in.
2. If there are multiple messages in the buffer, all but the
last message will be silently ignored.
3. If there are multiple messages and previous messages have
more parameters than the last one, the resulting event will
have a mixture of parameters from multiple messages.
Instead of doing all this, change the contract to "parse the
first valid message of interest in the buffer and return true,
or return false if there were no such messages", and update
the code and the comments accordingly.
2. Modify the caller (NetlinkListener) so it doesn't log an
error when parseBinaryNetlinkMessage returns false, because
this can now simply mean that we weren't interested in that
particular message. parseBinaryNetlinkMessage already logs
more informative errors.
3. Provide utility functions to check received message lengths and
to convert message types to message names.
4. Simplify logging duplicate attributes.
5. Use the appropriate IFLA_xxx macros instead of rolling our own
code to parse link state messages.
6. Move all the parsing code out to per-message-type parsing
functions to order to simplify parseBinaryNetlinkMessage.
Bug: 9180552
Change-Id: I6bbc2f7a104f618674dde2369c1fd5e93ea49430