Hi Jesse, On Tue, Apr 16, 2013 at 05:14:06PM +0900, Simon Horman wrote: > 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.
I'm wondering if you could look over this, I believe it addresses all the issues raised in your review of v5. > > > Status: > > I have dropped the RFC prefix from this series as I now believe > it is feature-complete. Any and all review is greatly appreciated. > > 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 patch depends on "[PATCH v2.24] datapath: Add basic MPLS support to > kernel". > There are currently no other patches in the recirculation series. > > > Availability: > > For reference this patch is available in git at: > git://github.com/horms/openvswitch.git devel/mpls-recirculate.v6 > > > Change Log: > > 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 (5): > Add execute_actions > Add set skb_mark support to execute_set_action > Add set skb_priority support to execute_set_action > Add set tunnel support to execute_set_action > Add packet recirculation > > 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 | 249 +++++----------- > lib/execute-actions.c | 225 +++++++++++++++ > lib/execute-actions.h | 34 +++ > lib/flow.h | 4 + > lib/odp-util.c | 17 +- > lib/odp-util.h | 4 + > ofproto/ofproto-dpif.c | 675 > ++++++++++++++++++++++++++++++++++++++----- > 12 files changed, 1032 insertions(+), 298 deletions(-) > create mode 100644 lib/execute-actions.c > create mode 100644 lib/execute-actions.h > > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
