ofp-actions: Add clone action.

This patch adds OpenFlow clone action with syntax as below:
"clone([action][,action...])".  The clone() action makes a copy of the
current packet and executes the list of actions against the packet,
without affecting the packet after the "clone(...)" action.  In other
word, the packet before the clone() and after the clone() is the same,
no matter what actions executed inside the clone().

Use case 1:
Set different fields and output to different ports without unset
actions=
  clone(mod_dl_src:<mac1>, output:1), clone(mod_dl_dst:<mac2>, output:2), output:3
Since each clone() has independent packet, output:1 has only dl_src modified,
output:2 has only dl_dst modified, output:3 has original packet.

Similar to case1
actions=
  push_vlan(...), output:2, pop_vlan, push_vlan(...), output:3
can be changed to
actions=
  clone(push_vlan(...), output:2),clone(push_vlan(...), output:3)
without having to add pop_vlan.

case 2: resubmit to another table without worrying packet being modified
  actions=clone(resubmit(1,2)), ...

Signed-off-by: William Tu <u9012063@gmail.com>
[blp@ovn.org revised this to omit the "sample" action]
Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/lib/ofp-actions.c b/lib/ofp-actions.c
index 09bd8c2bf..41d06fa31 100644
--- a/lib/ofp-actions.c
+++ b/lib/ofp-actions.c
@@ -325,6 +325,9 @@ enum ofp_raw_action_type {
     /* NX1.0+(39): struct nx_action_output_trunc. */
     NXAST_RAW_OUTPUT_TRUNC,
 
+    /* NX1.0+(42): struct ext_action_header, ... */
+    NXAST_RAW_CLONE,
+
 /* ## ------------------ ## */
 /* ## Debugging actions. ## */
 /* ## ------------------ ## */
@@ -454,6 +457,9 @@ ofpact_next_flattened(const struct ofpact *ofpact)
     case OFPACT_NAT:
         return ofpact_next(ofpact);
 
+    case OFPACT_CLONE:
+        return ofpact_get_CLONE(ofpact)->actions;
+
     case OFPACT_CT:
         return ofpact_get_CT(ofpact)->actions;
 
@@ -4798,6 +4804,78 @@ format_UNROLL_XLATE(const struct ofpact_unroll_xlate *a, struct ds *s)
                   colors.paren,   colors.end);
 }
 
+/* The NXAST_CLONE action is "struct ext_action_header", followed by zero or
+ * more embedded OpenFlow actions. */
+
+static enum ofperr
+decode_NXAST_RAW_CLONE(const struct ext_action_header *eah,
+                        enum ofp_version ofp_version,
+                        struct ofpbuf *out)
+{
+    int error;
+    struct ofpbuf openflow;
+    const size_t clone_offset = ofpacts_pull(out);
+    struct ofpact_nest *clone = ofpact_put_CLONE(out);
+
+    /* decode action list */
+    ofpbuf_pull(out, sizeof(*clone));
+    openflow = ofpbuf_const_initializer(
+                    eah + 1, ntohs(eah->len) - sizeof *eah);
+    error = ofpacts_pull_openflow_actions__(&openflow, openflow.size,
+                                            ofp_version,
+                                            1u << OVSINST_OFPIT11_APPLY_ACTIONS,
+                                            out, 0);
+    clone = ofpbuf_push_uninit(out, sizeof *clone);
+    out->header = &clone->ofpact;
+    ofpact_finish_CLONE(out, &clone);
+    ofpbuf_push_uninit(out, clone_offset);
+    return error;
+}
+
+static void
+encode_CLONE(const struct ofpact_nest *clone,
+              enum ofp_version ofp_version, struct ofpbuf *out)
+{
+    size_t len;
+    const size_t ofs = out->size;
+    struct ext_action_header *eah;
+
+    eah = put_NXAST_CLONE(out);
+    len = ofpacts_put_openflow_actions(clone->actions,
+                                       ofpact_nest_get_action_len(clone),
+                                       out, ofp_version);
+    len += sizeof *eah;
+    eah = ofpbuf_at(out, ofs, sizeof *eah);
+    eah->len = htons(len);
+}
+
+static char * OVS_WARN_UNUSED_RESULT
+parse_CLONE(char *arg, struct ofpbuf *ofpacts,
+             enum ofputil_protocol *usable_protocols)
+{
+    const size_t clone_offset = ofpacts_pull(ofpacts);
+    struct ofpact_nest *clone = ofpact_put_CLONE(ofpacts);
+    char *error;
+
+    ofpbuf_pull(ofpacts, sizeof *clone);
+    error = ofpacts_parse_copy(arg, ofpacts, usable_protocols, false, 0);
+    /* header points to the action list */
+    ofpacts->header = ofpbuf_push_uninit(ofpacts, sizeof *clone);
+    clone = ofpacts->header;
+
+    ofpact_finish_CLONE(ofpacts, &clone);
+    ofpbuf_push_uninit(ofpacts, clone_offset);
+    return error;
+}
+
+static void
+format_CLONE(const struct ofpact_nest *a, struct ds *s)
+{
+    ds_put_format(s, "%sclone(%s", colors.paren, colors.end);
+    ofpacts_format(a->actions, ofpact_nest_get_action_len(a), s);
+    ds_put_format(s, "%s)%s", colors.paren, colors.end);
+}
+
 /* Action structure for NXAST_SAMPLE.
  *
  * Samples matching packets with the given probability and sends them
@@ -6209,6 +6287,7 @@ ofpact_is_set_or_move_action(const struct ofpact *a)
     case OFPACT_BUNDLE:
     case OFPACT_CLEAR_ACTIONS:
     case OFPACT_CT:
+    case OFPACT_CLONE:
     case OFPACT_NAT:
     case OFPACT_CONTROLLER:
     case OFPACT_DEC_MPLS_TTL:
@@ -6285,6 +6364,7 @@ ofpact_is_allowed_in_actions_set(const struct ofpact *a)
      * the specification.  Thus the order in which they should be applied
      * in the action set is undefined. */
     case OFPACT_BUNDLE:
+    case OFPACT_CLONE:
     case OFPACT_CONTROLLER:
     case OFPACT_CT:
     case OFPACT_NAT:
@@ -6477,6 +6557,7 @@ ovs_instruction_type_from_ofpact_type(enum ofpact_type type)
         return OVSINST_OFPIT11_GOTO_TABLE;
     case OFPACT_OUTPUT:
     case OFPACT_GROUP:
+    case OFPACT_CLONE:
     case OFPACT_CONTROLLER:
     case OFPACT_ENQUEUE:
     case OFPACT_OUTPUT_REG:
@@ -7077,6 +7158,13 @@ ofpact_check__(enum ofputil_protocol *usable_protocols, struct ofpact *a,
     case OFPACT_SAMPLE:
         return 0;
 
+    case OFPACT_CLONE: {
+        struct ofpact_nest *on = ofpact_get_CLONE(a);
+        return ofpacts_check(on->actions, ofpact_nest_get_action_len(on),
+                             flow, max_ports, table_id, n_tables,
+                             usable_protocols);
+    }
+
     case OFPACT_CT: {
         struct ofpact_conntrack *oc = ofpact_get_CT(a);
 
@@ -7632,6 +7720,7 @@ ofpact_outputs_to_port(const struct ofpact *ofpact, ofp_port_t port)
     case OFPACT_POP_MPLS:
     case OFPACT_SAMPLE:
     case OFPACT_CLEAR_ACTIONS:
+    case OFPACT_CLONE:
     case OFPACT_WRITE_ACTIONS:
     case OFPACT_GOTO_TABLE:
     case OFPACT_METER: