This makes it easier to install the headers, or to use them directly from
another software package with -I$(openflow)/include, without invading
the top-level include file namespace.
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".
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.
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.
Ben Pfaff
Justin Pettit
Ben Pfaff
Martin Casado