forgot to reply-all:
Hi Ben,
I didn't quite yet understand why resubmit does not work for my case.
It could be the same flow table, I just need to search it twice:
-- once before decap, when hit, knows the flow needs to be decap'ed
and resubmitted to the table again
-- once after decap, with the destination IP of decap'ed packet.
This does not work?
Thanks!
On Sat, May 5, 2012 at 3:40 AM, Ben Pfaff <b...@nicira.com> wrote:
> The difference is that Yimin Chen wants to process the packet through
> two flow tables, one before and one after decap. With the normal way
> that gre tunnel processing works, you only get a shot at it after
> decap.
>
> On Fri, May 04, 2012 at 12:35:00PM -0700, Karl Yang wrote:
>> what is the difference between your this case and the "gre" tunnel
>> processing case within data path code?
>>
>> On Fri, May 4, 2012 at 10:05 AM, Ben Pfaff <b...@nicira.com> wrote:
>>
>> > No.
>> >
>> > On Fri, May 04, 2012 at 10:16:14AM +0800, YIMIN CHEN wrote:
>> > > Hi Ben,
>> > >
>> > > My goal is to implement a decap action that would decap a packet with
>> > > external IP addresses, and then have the decapped packet, with
>> > > internal IP addresses, do a flow lookup again.
>> > >
>> > > Can this be achieved using resubmit?
>> > >
>> > > Thanks!
>> > > Yimin
>> > >
>> > > On Fri, May 4, 2012 at 9:37 AM, Ben Pfaff <b...@nicira.com> wrote:
>> > > > You can read PORTING in the root of the tree.
>> > > >
>> > > > It would be best if you'd explain your goal first, instead of doing a
>> > > > deep dive into implementation details.
>> > > >
>> > > > On Fri, May 04, 2012 at 09:20:38AM +0800, YIMIN CHEN wrote:
>> > > >> Hi Ben,
>> > > >>
>> > > >> Thank you for the detailed information! I read this part of the code,
>> > > >> and have some confusion. Can you please review the following to see if
>> > > >> my understanding of code is correct?
>> > > >>
>> > > >> 1) ofproto/ code is userspace code, and datapath/ code is the actual
>> > dp code.
>> > > >> 2) ofproto handles the rule insertion from control plane, and datapath
>> > > >> handles the actual flow lookup.
>> > > >> 3) resubmit is handled in userspace? I saw the resubmit logic
>> > > >> xlate_nicira_action() is in ofproto I didn't see find any code in
>> > > >> datapath that handles resubmit, not even in ovs-ofctl.c. Is
>> > > >> xlate_nicira_action() doing flow insertion with resubmit action or
>> > > >> actually performing the dp actions? I am confused.
>> > > >>
>> > > >> What is the relationship between ofproto userspace and the dp code?
>> > > >> what is the difference between xlate table action and odp action?
>> > > >>
>> > > >> I think I am very confused, if there is any documentation I can read
>> > > >> to understand this design better, would you please give me a pointer?
>> > > >>
>> > > >> Thanks!
>> > > >> Yimin
>> > > >>
>> > > >> On Thu, May 3, 2012 at 11:30 AM, Ben Pfaff <b...@nicira.com> wrote:
>> > > >> > It's documented in nicira-ext.h:
>> > > >> >
>> > > >> > /* Action structures for NXAST_RESUBMIT and NXAST_RESUBMIT_TABLE.
>> > > >> > *
>> > > >> > * These actions search one of the switch's flow tables:
>> > > >> > *
>> > > >> > * - For NXAST_RESUBMIT_TABLE only, if the 'table' member is not
>> > 255, then
>> > > >> > * it specifies the table to search.
>> > > >> > *
>> > > >> > * - Otherwise (for NXAST_RESUBMIT_TABLE with a 'table' of 255,
>> > or for
>> > > >> > * NXAST_RESUBMIT regardless of 'table'), it searches the
>> > current flow
>> > > >> > * table, that is, the OpenFlow flow table that contains the
>> > flow from
>> > > >> > * which this action was obtained. If this action did not
>> > come from a
>> > > >> > * flow table (e.g. it came from an OFPT_PACKET_OUT message),
>> > then table 0
>> > > >> > * is the current table.
>> > > >> > *
>> > > >> > * The flow table lookup uses a flow that may be slightly modified
>> > from the
>> > > >> > * original lookup:
>> > > >> > *
>> > > >> > * - For NXAST_RESUBMIT, the 'in_port' member of struct
>> > nx_action_resubmit
>> > > >> > * is used as the flow's in_port.
>> > > >> > *
>> > > >> > * - For NXAST_RESUBMIT_TABLE, if the 'in_port' member is not
>> > OFPP_IN_PORT,
>> > > >> > * then its value is used as the flow's in_port. Otherwise,
>> > the original
>> > > >> > * in_port is used.
>> > > >> > *
>> > > >> > * - If actions that modify the flow (e.g. OFPAT_SET_VLAN_VID)
>> > precede the
>> > > >> > * resubmit action, then the flow is updated with the new
>> > values.
>> > > >> > *
>> > > >> > * Following the lookup, the original in_port is restored.
>> > > >> > *
>> > > >> > * If the modified flow matched in the flow table, then the
>> > corresponding
>> > > >> > * actions are executed. Afterward, actions following the resubmit
>> > in the
>> > > >> > * original set of actions, if any, are executed; any changes made
>> > to the
>> > > >> > * packet (e.g. changes to VLAN) by secondary actions persist when
>> > those
>> > > >> > * actions are executed, although the original in_port is restored.
>> > > >> > *
>> > > >> > * Resubmit actions may be used any number of times within a set of
>> > actions.
>> > > >> > *
>> > > >> > * Resubmit actions may nest to an implementation-defined depth.
>> > Beyond this
>> > > >> > * implementation-defined depth, further resubmit actions are
>> > simply ignored.
>> > > >> > *
>> > > >> > * NXAST_RESUBMIT ignores 'table' and 'pad'. NXAST_RESUBMIT_TABLE
>> > requires
>> > > >> > * 'pad' to be all-bits-zero.
>> > > >> > *
>> > > >> > * Open vSwitch 1.0.1 and earlier did not support recursion. Open
>> > vSwitch
>> > > >> > * before 1.2.90 did not support NXAST_RESUBMIT_TABLE.
>> > > >> > */
>> > > >> > struct nx_action_resubmit {
>> > > >> > ovs_be16 type; /* OFPAT_VENDOR. */
>> > > >> > ovs_be16 len; /* Length is 16. */
>> > > >> > ovs_be32 vendor; /* NX_VENDOR_ID. */
>> > > >> > ovs_be16 subtype; /* NXAST_RESUBMIT. */
>> > > >> > ovs_be16 in_port; /* New in_port for checking flow
>> > table. */
>> > > >> > uint8_t table; /* NXAST_RESUBMIT_TABLE: table
>> > to use. */
>> > > >> > uint8_t pad[3];
>> > > >> > };
>> > > >> > OFP_ASSERT(sizeof(struct nx_action_resubmit) == 16);
>> > > >> >
>> > > >> > and in ovs-ofctl(8):
>> > > >> >
>> > > >> > resubmit:port
>> > > >> > resubmit([port],[table])
>> > > >> > Re-searches this OpenFlow flow table (or the
>> > table whose
>> > > >> > number is specified by table) with the
>> > in_port field
>> > > >> > replaced by port (if port is specified) and
>> > executes the
>> > > >> > actions found, if any, in addition to any
>> > other actions
>> > > >> > in this flow entry.
>> > > >> >
>> > > >> > Recursive resubmit actions are obeyed up to an
>> > implemen‐
>> > > >> > tation-defined maximum depth. Open vSwitch
>> > 1.0.1 and
>> > > >> > earlier did not support recursion; Open
>> > vSwitch before
>> > > >> > 1.2.90 did not support table.
>> > > >> >
>> > > >> >
>> > > >> > On Thu, May 03, 2012 at 09:54:08AM +0800, YIMIN CHEN wrote:
>> > > >> >> Hi Ben,
>> > > >> >>
>> > > >> >> Thank you for your reply! I saw there is some code about resubmit
>> > > >> >> Nicira extension action, but that seems to be in userspace
>> > ofproto.c,
>> > > >> >> not in datapath, so I didn't know that is related. Could you help
>> > > >> >> clarify for me how does resubmit work?
>> > > >> >>
>> > > >> >>
>> > > >> >> Thanks!
>> > > >> >> Yimin
>> > > >> >>
>> > > >> >> On Wed, May 2, 2012 at 12:40 PM, Ben Pfaff <b...@nicira.com> wrote:
>> > > >> >> > On Wed, May 02, 2012 at 10:53:10AM +0800, YIMIN CHEN wrote:
>> > > >> >> >> I am looking at ovs dp code, and is looking at a correct way
>> > for a
>> > > >> >> >> flow to traverse the table twice. The goal is like this:
>> > > >> >> >>
>> > > >> >> >> flow lookup => tbl_lookup()
>> > > >> >> >> perform actions => execute_actions() which changes the packet
>> > > >> >> >> flow lookup using the new packet => tbl_lookup()
>> > > >> >> >> perform actions on the new packet => execute_actions.
>> > > >> >> >
>> > > >> >> > Do you want the "resubmit" Nicira extension action?
>> > _______________________________________________
>> > dev mailing list
>> > dev@openvswitch.org
>> > http://openvswitch.org/mailman/listinfo/dev
>> >
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