[ovs-dev] [PATCH v2 2/3] ovn: Add ct_commit(ct_mark=INTEGER); action.

[Russell Bryant]

Update the "ct_commit;" logical flow action to optionally take a
parameter, setting the value of "ct_mark" to a 32-bit integer.
Supported ct_commit syntax now includes:

    ct_commit;
    ct_commit();
    ct_commit(ct_mark=1);

Setting ct_mark via this type of logical flow results in an OpenFlow
flow that looks like:

    actions=ct(commit,zone=NXM_NX_REG5[0..15],exec(set_field:0x1->ct_mark))

A future commit will make use of this feature.

Signed-off-by: Russell Bryant <russell at ovn.org>
---
 ovn/lib/actions.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 ovn/ovn-sb.xml    | 13 ++++++++++--
 2 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/ovn/lib/actions.c b/ovn/lib/actions.c
index 42e7f3b..7119f62 100644
--- a/ovn/lib/actions.c
+++ b/ovn/lib/actions.c
@@ -184,7 +184,8 @@ add_prerequisite(struct action_context *ctx, const char *prerequisite)
 }
 
 static void
-emit_ct(struct action_context *ctx, bool recirc_next, bool commit)
+emit_ct(struct action_context *ctx, bool recirc_next, bool commit,
+        int *ct_mark)
 {
     struct ofpact_conntrack *ct = ofpact_put_CT(ctx->ofpacts);
     ct->flags |= commit ? NX_CT_F_COMMIT : 0;
@@ -210,6 +211,58 @@ emit_ct(struct action_context *ctx, bool recirc_next, bool commit)
 
     /* CT only works with IP, so set up a prerequisite. */
     add_prerequisite(ctx, "ip");
+
+    if (ct_mark) {
+        size_t set_field_offset = ctx->ofpacts->size;
+        ofpbuf_pull(ctx->ofpacts, set_field_offset);
+
+        struct ofpact_set_field *sf = ofpact_put_SET_FIELD(ctx->ofpacts);
+        sf->field = mf_from_id(MFF_CT_MARK);
+        sf->value.be32 = htonl(*ct_mark);
+        sf->mask.be32 = 0xFFFFFFFF;
+
+        ctx->ofpacts->header = ofpbuf_push_uninit(ctx->ofpacts, set_field_offset);
+        ct = ctx->ofpacts->header;
+        ofpact_finish(ctx->ofpacts, &ct->ofpact);
+    }
+}
+
+static void
+parse_ct_commit_action(struct action_context *ctx)
+{
+    if (!lexer_match(ctx->lexer, LEX_T_LPAREN)) {
+        /* ct_commit; */
+        emit_ct(ctx, false, true, NULL);
+        return;
+    } else if (lexer_match(ctx->lexer, LEX_T_RPAREN)) {
+        /* ct_commit(); */
+        emit_ct(ctx, false, true, NULL);
+        return;
+    }
+
+    /* ct_commit(ct_mark=0); */
+
+    if (!lexer_match_id(ctx->lexer, "ct_mark")) {
+        action_error(ctx, "Expected ct_mark after ct_commit(");
+        return;
+    }
+
+    if (!lexer_match(ctx->lexer, LEX_T_EQUALS)) {
+        action_error(ctx, "Expected '=' after ct_commit(ct_mark");
+        return;
+    }
+
+    int mark_value = 0;
+    if (!action_get_int(ctx, &mark_value)) {
+        return;
+    }
+
+    if (!lexer_match(ctx->lexer, LEX_T_RPAREN)) {
+        action_error(ctx, "Expected closing ) for ct_commit()");
+        return;
+    }
+
+    emit_ct(ctx, false, true, &mark_value);
 }
 
 static bool
@@ -236,9 +289,9 @@ parse_action(struct action_context *ctx)
             action_syntax_error(ctx, "expecting `--'");
         }
     } else if (lexer_match_id(ctx->lexer, "ct_next")) {
-        emit_ct(ctx, true, false);
+        emit_ct(ctx, true, false, NULL);
     } else if (lexer_match_id(ctx->lexer, "ct_commit")) {
-        emit_ct(ctx, false, true);
+        parse_ct_commit_action(ctx);
     } else {
         action_syntax_error(ctx, "expecting action");
     }
diff --git a/ovn/ovn-sb.xml b/ovn/ovn-sb.xml
index 476e870..10fb9b5 100644
--- a/ovn/ovn-sb.xml
+++ b/ovn/ovn-sb.xml
@@ -904,15 +904,24 @@
         </dd>
 
         <dt><code>ct_commit;</code></dt>
+        <dt><code>ct_commit(ct_mark=VALUE);</code></dt>
         <dd>
           <p>
             Commit the flow to the connection tracking entry associated
-            with it by a previous call to <code>ct_next</code>.
+            with it by a previous call to <code>ct_next</code>.  When
+            the ct_mark=VALUE parameter is supplied, ct_mark will be set
+            to the 32-bit integer indicated by VALUE on the connection
+            tracking entry.
           </p>
+
           <p>
             Note that if you want processing to continue in the next table,
             you must execute the <code>next</code> action after
-            <code>ct_commit</code>.
+            <code>ct_commit</code>.  You may also leave out <code>next</code>
+            which will commit connection tracking state, and then drop the
+            packet.  This could be useful for seting <code>ct_mark</code>
+            on a connection tracking entry before dropping a packet,
+            for example.
           </p>
         </dd>
       </dl>
-- 
2.5.0