vtep: Add source node replication support.

This patch updates the vtep schema, vtep-ctl commands and vtep simulator
to support source node replication in addition to service node
replication per logical switch.  The default replication mode is service
node as that was the only mode previously supported.  Source node
replication mode is optionally configurable and clearing the replication
mode implicitly sets the replication mode back to a default of service
node.

Signed-off-by: Darrell Ball <dlu998@gmail.com>
Acked-by: Bruce Davie <bdavie@vmware.com>
Acked-by: Anupam Chanda <achanda@vmware.com>
Signed-off-by: Justin Pettit <jpettit@ovn.org>

6 files changed, 194 insertions, 13 deletions

diff --git a/vtep/README.ovs-vtep.md b/vtep/README.ovs-vtep.md
index 6734dabfc..13d4e1d36 100644
--- a/vtep/README.ovs-vtep.md
+++ b/vtep/README.ovs-vtep.md
@@ -166,13 +166,39 @@ vtep-ctl bind-ls br0 p0 0 ls0
 vtep-ctl set Logical_Switch ls0 tunnel_key=33
       ```
 
-3. Direct unknown destinations out a tunnel:
+3. Direct unknown destinations out a tunnel.
+
+   For handling L2 broadcast, multicast and unknown unicast traffic,
+   packets can be sent to all members of a logical switch referenced by
+   a physical switch.  The "unknown-dst" address below is used to
+   represent these packets.  There are different modes to replicate the
+   packets.  The default mode of replication is to send the traffic to a
+   service node, which can be a hypervisor, server or appliance, and let
+   the service node handle replication to other transport nodes
+   (hypervisors or other VTEP physical switches).  This mode is called
+   _service node_ replication.  An alternate mode of replication, called
+   _source node_ replication, involves the source node sending to all
+   other transport nodes.  Hypervisors are always responsible for doing
+   their own replication for locally attached VMs in both modes.
+   Service node mode is the default.  Service node replication mode is
+   considered a basic requirement because it only requires sending the
+   packet to a single transport node.  The following configuration is
+   for service node replication mode as only a single transport node
+   destination is specified for the unknown-dst address:
 
       ```
 vtep-ctl add-mcast-remote ls0 unknown-dst 10.2.2.2
       ```
 
-4. Direct unicast destinations out a different tunnel:
+4. Optionally, change the replication mode from a default of
+"service\_node" to "source\_node", which can be done at the logical
+switch level:
+
+      ```
+vtep-ctl set-replication-mode ls0 source_node
+      ```
+
+5. Direct unicast destinations out a different tunnel:
 
       ```
 vtep-ctl add-ucast-remote ls0 00:11:22:33:44:55 10.2.2.3
diff --git a/vtep/ovs-vtep b/vtep/ovs-vtep
index 31ff15928..a8ffb668a 100755
--- a/vtep/ovs-vtep
+++ b/vtep/ovs-vtep
@@ -94,6 +94,7 @@ class Logical_Switch(object):
         self.unknown_dsts = set()
         self.tunnel_key = 0
         self.setup_ls()
+        self.replication_mode = "service_node"
 
     def __del__(self):
         vlog.info("destroying lswitch %s" % self.name)
@@ -141,13 +142,17 @@ class Logical_Switch(object):
             ovs_ofctl("add-flow %s table=1,priority=1,in_port=%s,action=%s"
                         % (self.short_name, port_no, ",".join(flood_ports)))
 
-        # Traffic coming from a VTEP physical port should only be flooded to
-        # one 'unknown-dst' and to all other physical ports that belong to that
-        # VTEP device and this logical switch.
+        # Traffic coming from a VTEP physical port should always be flooded to
+        # all the other physical ports that belong to that VTEP device and
+        # this logical switch.  If the replication mode is service node then
+        # send to one unknown_dst node (the first one here); else we assume the
+        # replication mode is source node and we send the packet to all
+        # unknown_dst nodes.
         for tunnel in self.unknown_dsts:
             port_no = self.tunnels[tunnel][0]
             flood_ports.append(port_no)
-            break
+            if self.replication_mode == "service_node":
+                break
 
         ovs_ofctl("add-flow %s table=1,priority=0,action=%s"
                   % (self.short_name, ",".join(flood_ports)))
@@ -293,8 +298,30 @@ class Logical_Switch(object):
 
         self.remote_macs = remote_macs
 
+        replication_mode = vtep_ctl("get logical_switch %s replication_mode"
+                                    % self.name)
+
+        # Replication mode is an optional column and if it is not set,
+        # replication mode defaults to service_node.
+        if replication_mode == "[]":
+            replication_mode = "service_node"
+
+        # If the logical switch level replication mode has changed then
+        # update to that value.
+        update_flood_set = False
+        if replication_mode != self.replication_mode:
+            self.replication_mode = replication_mode
+            vlog.info("%s replication mode changed to %s" %
+                      (self.name, self.replication_mode))
+            update_flood_set = True
+
         if (self.unknown_dsts != unknown_dsts):
             self.unknown_dsts = unknown_dsts
+            update_flood_set = True
+
+        # If either the replication mode has changed or the unknown
+        # destinations set has changed, update the flooding decision.
+        if update_flood_set is True:
             self.update_flood()
 
     def update_stats(self):
diff --git a/vtep/vtep-ctl.8.in b/vtep/vtep-ctl.8.in
index 129c7ed63..e0f49a78d 100644
--- a/vtep/vtep-ctl.8.in
+++ b/vtep/vtep-ctl.8.in
@@ -195,6 +195,32 @@ combination on the physical switch \fIpswitch\fR.
 List the logical switch bindings for \fIport\fR on the physical switch
 \fIpswitch\fR.
 .
+.IP "\fBset\-replication\-mode \fIlswitch replication\-mode\fR"
+Set logical switch \fIlswitch\fR replication mode to
+\fIreplication\-mode\fR; the only valid values for replication mode
+are "service_node" and "source_node".
+.
+For handling L2 broadcast, multicast and unknown unicast traffic,
+packets can be sent to all members of a logical switch referenced by
+a physical switch.  There are different modes to replicate the
+packets.  The default mode of replication is to send the traffic to
+a service node, which can be a hypervisor, server or appliance, and
+let the service node handle replication to other transport nodes
+(hypervisors or other VTEP physical switches).  This mode is called
+service node replication.  An alternate mode of replication, called
+source node replication involves the source node sending to all
+other transport nodes.  Hypervisors are always responsible for doing
+their own replication for locally attached VMs in both modes.
+Service node mode is the default, if the replication mode is not
+explicitly set.  Service node replication mode is considered a basic
+requirement because it only requires sending the packet to a single
+transport node.
+.
+.IP "\fBget\-replication\-mode \fIlswitch\fR"
+Get logical switch \fIlswitch\fR replication mode.  The only valid values
+for replication mode are "service_node" and "source_node".  An empty reply
+for replication mode implies a default of "service_node".
+.
 .SS "Logical Router Commands"
 These commands examine and manipulate logical routers.
 .
diff --git a/vtep/vtep-ctl.c b/vtep/vtep-ctl.c
index 29d9a1773..5c189712c 100644
--- a/vtep/vtep-ctl.c
+++ b/vtep/vtep-ctl.c
@@ -335,6 +335,8 @@ Logical Switch commands:\n\
   bind-ls PS PORT VLAN LS     bind LS to VLAN on PORT\n\
   unbind-ls PS PORT VLAN      unbind logical switch on VLAN from PORT\n\
   list-bindings PS PORT       list bindings for PORT on PS\n\
+  set-replication-mode LS MODE  set replication mode on LS\n\
+  get-replication-mode LS       get replication mode on LS\n\
 \n\
 Logical Router commands:\n\
   add-lr LR                   create a new logical router named LR\n\
@@ -851,6 +853,8 @@ pre_get_info(struct ctl_context *ctx)
     ovsdb_idl_add_column(ctx->idl, &vteprec_physical_port_col_vlan_bindings);
 
     ovsdb_idl_add_column(ctx->idl, &vteprec_logical_switch_col_name);
+    ovsdb_idl_add_column(ctx->idl,
+                         &vteprec_logical_switch_col_replication_mode);
 
     ovsdb_idl_add_column(ctx->idl, &vteprec_logical_router_col_name);
 
@@ -1523,6 +1527,39 @@ cmd_unbind_ls(struct ctl_context *ctx)
     vtep_ctl_context_invalidate_cache(ctx);
 }
 
+static void
+cmd_set_replication_mode(struct ctl_context *ctx)
+{
+    struct vtep_ctl_context *vtepctl_ctx = vtep_ctl_context_cast(ctx);
+    struct vtep_ctl_lswitch *ls;
+    const char *ls_name = ctx->argv[1];
+
+    vtep_ctl_context_populate_cache(ctx);
+
+    if (strcmp(ctx->argv[2], "service_node") &&
+        strcmp(ctx->argv[2], "source_node")) {
+        ctl_fatal("Replication mode must be 'service_node' or 'source_node'");
+    }
+
+    ls = find_lswitch(vtepctl_ctx, ls_name, true);
+    vteprec_logical_switch_set_replication_mode(ls->ls_cfg, ctx->argv[2]);
+
+    vtep_ctl_context_invalidate_cache(ctx);
+}
+
+static void
+cmd_get_replication_mode(struct ctl_context *ctx)
+{
+    struct vtep_ctl_context *vtepctl_ctx = vtep_ctl_context_cast(ctx);
+    struct vtep_ctl_lswitch *ls;
+    const char *ls_name = ctx->argv[1];
+
+    vtep_ctl_context_populate_cache(ctx);
+
+    ls = find_lswitch(vtepctl_ctx, ls_name, true);
+    ds_put_format(&ctx->output, "%s\n", ls->ls_cfg->replication_mode);
+}
+
 static struct vtep_ctl_lrouter *
 find_lrouter(struct vtep_ctl_context *vtepctl_ctx,
              const char *name, bool must_exist)
@@ -2459,6 +2496,10 @@ static const struct ctl_command_syntax vtep_commands[] = {
     {"list-bindings", 2, 2, NULL, pre_get_info, cmd_list_bindings, NULL, "", RO},
     {"bind-ls", 4, 4, NULL, pre_get_info, cmd_bind_ls, NULL, "", RO},
     {"unbind-ls", 3, 3, NULL, pre_get_info, cmd_unbind_ls, NULL, "", RO},
+    {"set-replication-mode", 2, 2, "LS MODE", pre_get_info,
+        cmd_set_replication_mode, NULL, "", RW},
+    {"get-replication-mode", 1, 1, "LS", pre_get_info,
+        cmd_get_replication_mode, NULL, "", RO},
 
     /* Logical Router commands. */
     {"add-lr", 1, 1, NULL, pre_get_info, cmd_add_lr, NULL, "--may-exist", RW},
diff --git a/vtep/vtep.ovsschema b/vtep/vtep.ovsschema
index 533fd2e57..e409d8d56 100644
--- a/vtep/vtep.ovsschema
+++ b/vtep/vtep.ovsschema
@@ -1,6 +1,6 @@
 {
   "name": "hardware_vtep",
-  "cksum": "770244945 11113",
+  "cksum": "4127261095 11302",
   "tables": {
     "Global": {
       "columns": {
@@ -96,6 +96,11 @@
         "name": {"type": "string"},
         "description": {"type": "string"},
         "tunnel_key": {"type": {"key": "integer", "min": 0, "max": 1}},
+        "replication_mode": {
+          "type": {
+            "key": {
+              "enum": ["set", ["service_node", "source_node"]],
+              "type": "string"},"min": 0, "max": 1}},
         "other_config": {
           "type": {"key": "string", "value": "string",
                    "min": 0, "max": "unlimited"}}},
@@ -296,4 +301,4 @@
           "ephemeral": true}},
       "indexes": [["target"]],
       "isRoot": false}},
-  "version": "1.5.1"}
+  "version": "1.6.0"}
diff --git a/vtep/vtep.xml b/vtep/vtep.xml
index a3a69885e..ad014ab5d 100644
--- a/vtep/vtep.xml
+++ b/vtep/vtep.xml
@@ -357,6 +357,28 @@
         Indicates that an error has occurred in the switch but that no
         more specific information is available.
       </column>
+
+      <column name="switch_fault_status"
+        key="unsupported_source_node_replication">
+        Indicates that the requested source node replication mode cannot be
+        supported by the physical switch;  this specifically means in this
+        context that the physical switch lacks the capability to support
+        source node replication mode.  This error occurs when a controller
+        attempts to set source node replication mode for one of the logical
+        switches that the physical switch is keeping context for.  An NVC
+        that observes this error should take appropriate action (for example
+        reverting the logical switch to service node replication mode).
+        It is recommended that an NVC be proactive and test for support of
+        source node replication by using a test logical switch on vtep
+        physical switch nodes and then trying to change the replication mode
+        to source node on this logical switch, checking for error.  The NVC
+        could remember this capability per vtep physical switch.  Using
+        mixed replication modes on a given logical switch is not recommended.
+        Service node replication mode is considered a basic requirement
+        since it only requires sending a packet to a single transport node,
+        hence it is not expected that a switch should report that service
+        node mode cannot be supported.
+      </column>
     </group>
 
     <group title="Common Column">
@@ -754,6 +776,35 @@
       </column>
     </group>
 
+    <group title="Replication Mode">
+      <p>
+        For handling L2 broadcast, multicast and unknown unicast traffic,
+        packets can be sent to all members of a logical switch referenced by
+        a physical switch.  There are different modes to replicate the
+        packets.  The default mode of replication is to send the traffic to
+        a service node, which can be a hypervisor, server or appliance, and
+        let the service node handle replication to other transport nodes
+        (hypervisors or other VTEP physical switches).  This mode is called
+        service node replication.  An alternate mode of replication, called
+        source node replication involves the source node sending to all
+        other transport nodes.  Hypervisors are always responsible for doing
+        their own replication for locally attached VMs in both modes.
+        Service node replication mode is the default and considered a
+        basic requirement because it only requires sending the packet to
+        a single transport node.
+      </p>
+
+      <column name="replication_mode">
+        <p>
+          This optional column defines the replication mode per
+          <ref table="Logical_Switch"/>.  There are 2 valid values,
+          <code>service_node</code> and <code>source_node</code>.  If the
+          column is not set, the replication mode defaults to service_node.
+        </p>
+
+      </column>
+    </group>
+
     <group title="Identification">
       <column name="name">
         Symbolic name for the logical switch.
@@ -887,8 +938,8 @@
       Multicast packet replication may be handled by a service node,
       in which case the physical locators will be IP addresses of
       service nodes. If the VTEP supports replication onto multiple
-      tunnels, then this may be used to replicate directly onto
-      VTEP-hypervisor tunnels.
+      tunnels, using source node replication, then this may be used to
+      replicate directly onto VTEP-hypervisor or VTEP-VTEP tunnels.
     </p>
 
     <column name="MAC">
@@ -911,9 +962,14 @@
 
     <column name="locator_set">
       The physical locator set to be used to reach this MAC address. In
-      this table, the physical locator set will be either a service node IP
-      address or a set of tunnel IP addresses of hypervisors (and
-      potentially other VTEPs).
+      this table, the physical locator set will be either a set of service
+      nodes when service node replication is used or the set of transport
+      nodes (defined as hypervisors or VTEPs) participating in the associated
+      logical switch, when source node replication is used. When service node
+      replication is used, the VTEP should send packets to one member of the
+      locator set that is known to be healthy and reachable, which could be
+      determined by BFD.  When source node replication is used, the VTEP
+      should send packets to all members of the locator set.
     </column>
 
     <column name="ipaddr">