ofproto-dpif: Fake-up OFPP_NONE input bundle for mirroring and normal.

Both mirroring and "normal" processing make use of the input bundle to
perform various sanity checks.  Controller-generated traffic typically
uses an ingress port of OFPP_NONE, which doesn't have a corresponding
input bundle.  This commit fakes one up well enough that mirroring and
"normal" processing succeed.

We looked at creating an actual bundle based on the "real" OFPP_NONE.
This was even uglier, since there were even more special-cases that
needed to be handled, including having to hide it from port queries.

Reported-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Justin Pettit <jpettit@nicira.com>

Author: Justin Pettit

ofproto/ofproto-dpif.c

@@ -179,6 +179,16 @@ static void bundle_wait(struct ofbundle *);
 static struct ofbundle *lookup_input_bundle(struct ofproto_dpif *,
                                             uint16_t in_port, bool warn);
 
+/* A controller may use OFPP_NONE as the ingress port to indicate that
+ * it did not arrive on a "real" port.  'ofpp_none_bundle' exists for
+ * when an input bundle is needed for validation (e.g., mirroring or
+ * OFPP_NORMAL processing).  It is not connected to an 'ofproto' or have
+ * any 'port' structs, so care must be taken when dealing with it. */
+static struct ofbundle ofpp_none_bundle = {
+    .name      = "OFPP_NONE",
+    .vlan_mode = PORT_VLAN_TRUNK
+};
+
 static void stp_run(struct ofproto_dpif *ofproto);
 static void stp_wait(struct ofproto_dpif *ofproto);
 
@@ -4858,6 +4868,11 @@ input_vid_to_vlan(const struct ofbundle *in_bundle, uint16_t vid)
 static bool
 input_vid_is_valid(uint16_t vid, struct ofbundle *in_bundle, bool warn)
 {
+    /* Allow any VID on the OFPP_NONE port. */
+    if (in_bundle == &ofpp_none_bundle) {
+        return true;
+    }
+
     switch (in_bundle->vlan_mode) {
     case PORT_VLAN_ACCESS:
         if (vid) {
@@ -5171,6 +5186,11 @@ update_learning_table(struct ofproto_dpif *ofproto,
 {
     struct mac_entry *mac;
 
+    /* Don't learn the OFPP_NONE port. */
+    if (in_bundle == &ofpp_none_bundle) {
+        return;
+    }
+
     if (!mac_learning_may_learn(ofproto->ml, flow->dl_src, vlan)) {
         return;
     }
@@ -5206,6 +5226,12 @@ lookup_input_bundle(struct ofproto_dpif *ofproto, uint16_t in_port, bool warn)
 {
     struct ofport_dpif *ofport;
 
+    /* Special-case OFPP_NONE, which a controller may use as the ingress
+     * port for traffic that it is sourcing. */
+    if (in_port == OFPP_NONE) {
+        return &ofpp_none_bundle;
+    }
+
     /* Find the port and bundle for the received packet. */
     ofport = get_ofp_port(ofproto, in_port);
     if (ofport && ofport->bundle) {
@@ -5299,7 +5325,8 @@ xlate_normal(struct action_xlate_ctx *ctx)
         return;
     }
 
-    /* We know 'in_port' exists, since lookup_input_bundle() succeeded. */
+    /* We know 'in_port' exists unless it is "ofpp_none_bundle",
+     * since lookup_input_bundle() succeeded. */
     in_port = get_ofp_port(ctx->ofproto, ctx->flow.in_port);
 
     /* Drop malformed frames. */
@@ -5333,7 +5360,8 @@ xlate_normal(struct action_xlate_ctx *ctx)
     vlan = input_vid_to_vlan(in_bundle, vid);
 
     /* Check other admissibility requirements. */
-    if (!is_admissible(ctx->ofproto, &ctx->flow, in_port, vlan, &ctx->tags)) {
+    if (in_port &&
+         !is_admissible(ctx->ofproto, &ctx->flow, in_port, vlan, &ctx->tags)) {
         return;
     }
 

tests/ofproto-dpif.at

@@ -460,6 +460,36 @@ AT_CHECK_UNQUOTED([tail -1 stdout], [0],
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
+AT_SETUP([ofproto-dpif - mirroring, OFPP_NONE ingress port])
+OVS_VSWITCHD_START(
+       [add-port br0 p1 -- set Interface p1 type=dummy --\
+        add-port br0 p2 -- set Interface p2 type=dummy --\
+        set Bridge br0 mirrors=@m --\
+        --id=@p2 get Port p2 --\
+        --id=@m create Mirror name=mymirror \
+        select_all=true output_port=@p2], [<0>
+])
+
+AT_CHECK(
+  [ovs-vsctl \
+        -- get Interface p1 ofport \
+        -- get Interface p2 ofport],
+  [0], [stdout])
+set `cat stdout`
+p1=$1 p2=$2
+
+AT_CHECK([ovs-ofctl add-flow br0 action=output:1])
+
+# "in_port" defaults to OFPP_NONE if it's not specified.
+flow="eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=1,tos=0,ttl=128,frag=no),icmp(type=8,code=0)"
+AT_CHECK([ovs-appctl ofproto/trace br0 "$flow"], [0], [stdout])
+AT_CHECK_UNQUOTED([tail -1 stdout], [0],
+  [Datapath actions: $p1,$p2
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
 
 AT_SETUP([ofproto-dpif - mirroring, select_dst])
 OVS_VSWITCHD_START(