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?
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