Recirculation is a technique to allow a frame to re-enter
frame processing. This is intended to be used after actions
have been applied to the frame with modify the frame in
some way that makes it possible for richer processing to occur.
An example is and indeed targeted use case is MPLS. If an MPLS frame has an
mpls_pop action applied with the IPv4 ethernet type then it becomes
possible to decode the IPv4 portion of the frame. This may be used to
construct a facet that modifies the IPv4 portion of the frame. This is not
possible prior to the mpls_pop action as the contents of the frame after
the MPLS stack is not known to be IPv4.
Design:
* New recirculation action.
ovs-vswitchd adds a recirculation action to the end of a list of
datapath actions for a flow when the actions are truncated because
insufficient flow match information is available to add the next
OpenFlow action. The recirculation action is preceded by an action
to set the skb_mark to an id which can be used to scope a facet lookup
of a recirculated packet.
e.g. pop_mpls(0x0800),dec_ttl becomes
pop_mpls(0x800),set(skb_mark(id)),recirculate
* Datapath behaviour
Then the datapath encounters a recirculate action it:
+ Recalculates the flow key based on the packet
which will typically have been modified by previous actions
+ As the recirculate action is preceded by a set(skb_mark(id)) action,
the new match key will now include skb_mark=id.
+ Performs a lookup using the new match key
+ Processes the packet if a facet matches the key or;
+ Makes an upcall if necessary
* No facet behaviour
+ Loop:
1) translate actions
2) If there is a recirculate action, execute packet
and go back to 1) for remaining actions.
Base/Pre-requisites:
This series applies to the git master branch on openvswtich.org
and doees not have any pre-requisites.
Availability:
For reference this series is available in git at:
git://github.com/horms/openvswitch.git devel/mpls-recirculate.v11
TODO:
* Conclude discussion with Jesse Gross on weather or not packets
are not output by do_execute_actions() if an output action precedes
a recirculate action.
* Review of fproto/ofproto-dpif.c by Jesse Gross (and Ben Pfaff?)
Change Log:
v11
* Add patches to handle multiple levels of push and pop
* Addressed review by Jarno Rajahalme
v10
* As suggested by Ben Pfaff
- Rename lib/execute-actions.[ch] as lib/odp-execute.[ch]
- Sort headers in alphabetical order
- Minimise includes in lib/odp-execute.h
- Include lib/odp-execute.h immediately after config.h in lib/odp-execute.c
- Correct coding style of prototype of tun_key_from_attr
- Remove dubious memset from set_tunnel_action
- use {} with if statement for OVS_ACTION_ATTR_OUTPUT in execute_actions()
- Do not put required side effects in conditions for ovs_assert();
- Remove execute_actions_for_recircualtion() helper and
use odp_execute_actions directly()
v9
* As suggested by Jesse Gross
- Follow the convention on other code that when passing around
a void pointer and casting it, the variable named with an underscore
is the void pointer.
- Move extraction of userspace data into execute_actions().
Previously it was in the userspace callback passed to execute_actions().
- Remove ovs_assert() calls from execute_actions().
They seem unnecessary at best.
- Reduce the number of new parameters added to functions,
in many cases to zero, by using the skb_priority, skb_mark
and tunnel elements of struct flow.
- Add patch to make use of execute_actions() to execute controller actions
v8
* For a learn action recirculate regardless of the value of
ctx->may_learn in do_xlate_actions(). Previously recirculation
only occurred if ctx->may_learn was true. That is a bug as it causes
revalidation to fail. Flagged by the tests developed as part of a patch
to allow multiple MPLS push and poop actions.
* Update tests removing unnecessary dl_type pre-requisite
v7
* Rebase
* Add skb_priority, skb_mark and tun_key parameters to dp_netdev_port_input()
This allows the skb_priority, skb_mark and tun_key to be passed from
dpif_netdev_execute() to honour corresponding set actions.
* Recirculate on reg load and move, stack push and pop,
multipath, bundle, and learn actions.
* Add tests
v6
* Rearange patches so as only to add self-contained working chages
* Create execute_actions() in lib/execute-actions.c
- This moves makes much more action execution code than before
from the user-spcace datapath into common library code.
* Add set skb_priority support to execute_set_action()
* Add set tunnel support to execute_set_action()
* Support revalidation of facets for recirculated packets
* Address other elements Jesse's review, as noted in
per-patch changelogs
v5
* Correct declaration of facet_find_by_id to match definition:
ovs_be32 -> uint32_t.
* Enhancements to recirculation id code:
- Allow efficient lookup of facets by their recirculation id
- Add RECIRCULATION_ID_DUMMY which may be used in cases
where no facet it used. It is an arbitrary valid id.
- Also add recirculated element to action_xlate_ctx()
to use to detect if a recirculation action was added during
translation. The previous scheme of checking if recirculation_id
was not RECIRCULATION_ID_NONE is broken for cases where
the context is initialised with a recirculation_id other than
RECIRCULATION_ID_NONE. E.g. when RECIRCULATION_ID_DUMMY is used.
- Avoid id collision
rfc4:
* Allow recirculation without facets in ovs-vswitchd
- Handle flow miss without facet
- Packet out
* Minor enhancement to recirculation id management: Add RECIRCULATE_ID_NONE
to use instead of using 0 directly.
* Correct calculation of facet->recirculation_ofpacts and
facet->recirculation_ofpacts_len in subfacet_make_actions()
in the case of more than one level of recirculation.
rfc3
* Use IS_ERR_OR_NULL()
* Handle facet consistency checking by constructing a chain of facets
from the given facet, to its recirculation parent and then its parent
until the topmost facet. If there is no recirculation the chain will
be of length one. If there is one recirculation action then the chain
will be of length two. And so on.
The topmost facet in the chain can is used to lookup the rule to be
verified. The chain is then walked from top to bottom, translating
actions up to the end or the first recirculation action that is
encountered, whichever comes first. As the code walks down the chain
it updates the actions that are executed to start of the actions to
be executed to be just after the end of the actions executed in the
previous facet in the chain. This is similar to the way that facets
are created when a recirculation action is encountered.
rfc2
* As suggested by Jesse Gross
- Update for changes to ovs_dp_process_received_packet()
to no longer check if OVS_CB(skb)->flow is pre-initialised.
- Do not add spurious printk debugging to ovs_execute_actions()
- Do not add spurious debugging messages to commit_set_nw_action()
- Correct typo in comment above commit_odp_actions().
- Do not execute recirculation in ovs-vswitchd, rather allow
the datapath to make an upcall when a recirculation action
is encountered on execute.
+ This implicitly breaks support for recirculation without facets,
so for now force all misses of MPLS frames to be handled with
a facet; and treat handling of recirculation for packet_out as
a todo item.
- Use skb_mark for recirculation_id in match. This avoids
both expanding the match and including a recirculation_id parameter
with the recirculation action: set_skb_mark should be used before
the recirculation action.
- Tidy up ownership of skb in ovs_execute_actions
rfc1
* Initial post
Patch List and Diffstat:
Simon Horman (6):
Add execute_actions
Add set skb_mark, set_priority and tunnel support to
execute_set_action
ofproto-dpif: Use execute_actions to execute controller actions
Add packet recirculation
Always update ethertype on mpls_pop
Allow multiple levels of MPLS push and pop
datapath/actions.c | 9 +-
datapath/datapath.c | 105 ++++--
datapath/datapath.h | 2 +-
include/linux/openvswitch.h | 4 +
lib/automake.mk | 2 +
lib/dpif-netdev.c | 248 ++++--------
lib/flow.c | 6 +-
lib/flow.h | 13 +-
lib/match.c | 2 +-
lib/nx-match.c | 2 +-
lib/odp-execute.c | 224 +++++++++++
lib/odp-execute.h | 37 ++
lib/odp-util.c | 66 ++--
lib/odp-util.h | 4 +
lib/ofp-actions.c | 6 -
lib/ofp-util.c | 5 +-
lib/packets.c | 36 +-
lib/packets.h | 2 -
ofproto/ofproto-dpif.c | 869 ++++++++++++++++++++++++++++++++++++-------
tests/ofproto-dpif.at | 627 ++++++++++++++++++++++++++++++-
tests/test-bundle.c | 1 -
tests/test-multipath.c | 1 -
utilities/ovs-dpctl.c | 2 +-
utilities/ovs-ofctl.8.in | 21 +-
24 files changed, 1814 insertions(+), 480 deletions(-)
create mode 100644 lib/odp-execute.c
create mode 100644 lib/odp-execute.h
--
1.7.10.4
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