Allow vendors to define their own actions. Actions were originally fixed-
length, which was a bit constraining. Actions now contain a length field,
which gives them more flexibility.
This cleans up the handling of modifying existing flows. There now exists
OFPFC_MODIFY and OFPFC_MODIFY_STRICT commands, which have the same matching
characteristics to their OFPFC_DELETE* counterparts. When adding a flow that
already exists, the counters and timers are now reset (ie, its treated as a
new flow). This commit also adds the "--strict" option to dpctl to allow
strict matching for "mod-flows" and "del-flows".
Older versions of OpenFlow pre-defined a few different types of tables and the
Features Reply message would indicate how many of those entries existed. This
was very inflexible, so now the Features Reply just indicates how many tables
there are. The controller now sends a Table Stats request to find out how
many entries are supported and the fields that can be wildcarded.
This change also removes the "buffer_mb" field from the Features Reply, since
it was not being used and seemed to be of limited value.
This updates the OpenFlow protocol version and changes the names of
structure members, so any software that uses OpenFlow will need to be
updated to match.
The table insert and delete functions are already fully serialized
on dp_mutex (and genl_mutex), so there's no need for them to use
additional spinlocks.
There was little point in taking the dp_mutex farther down in the
code than dp_genl_openflow, since that function is already completely
serialized by genl_rcv across the genl_mutex. We could get rid of
dp_mutex completely, except that we still need it to serialize timeout.
There is no need for a "safe" version of the RCU list iteration macros,
because the ordinary version of the macros is "safe". Linux 2.6.26-rc1
removed these "safe" versions, so this change modifies OpenFlow's uses
of these macros to use the ordinary versions. This also simplifies the
code because we don't need to use the list_entry macros any longer.
Now the number of actions is limited, as a practical matter, to the size
of the buffer that the kernel provides for Netlink dumps, which is usually
4096 bytes. A flow statistics entry must fit in a single one of these
buffers. Actions are 8 bytes each, so this is about 500 actions
considering overhead.
This changes the kernel switch implementation to use the kernel Netlink
"dump" interface to allow flow stats that don't fit in the socket buffer
to be dumped gradually as the caller drains the socket buffer.
One of the changes here is a bug fix for nla_unreserve. Because Netlink
attributes' lengths are rounded up to a multiple of 4 bytes, reducing
the length of the payload by N bytes doesn't necessarily reduce the
length of the skb by N bytes. Instead, we need to know the original
length and final length of the attribute. This means that using 'len'
as a difference in bytes doesn't really make sense, so this changes
'len' to be the new length of the attribute payload and renames the
function to nla_shrink to (IMO) better reflect what it is now doing.
Since we have to release the RCU read lock between calls to the dump
function, we need table iterators that persist across RCU epochs. One
way to do this would be to add new "iterator_save" and "iterator_restore"
functions, but this seemed like overkill since there would then be a
total of 5 iterator functions that have only one user (flow stats dumping).
Instead, this patch refactors table iteration into a single "iterate"
function that takes a callback. This simplifies the table iteration code
significantly.
This change also modifies dpctl to understand the new format of flow
stats.
We want to allow multiple OpenFlow connections to a switch, so that
dpctl and other management tools can also connect to a switch that
is connecte to the controller. These tools will want to fetch the
information in the data_hello message, but currently this can only
be done by sending a control_hello message, which changes the
switch configuration state. So breaking the hello messages up into
multiple different messages, only some of which affect configuration
state, cures the problem.
Also, clean up the kernel datapath a bit, by adding helper functions
for allocating and resizing Generic Netlink messages that encapsulate
OpenFlow messages.
Justin Pettit
Ben Pfaff
Ben Pfaff
Martin Casado