cfm: New cfm extended mode.

The new extended mode introduced in this patch will be used for
features which break wire compatibility with 802.1ag compliant
implementations.

Bug #7014.

5 files changed, 28 insertions, 7 deletions

diff --git a/lib/cfm.c b/lib/cfm.c
index 6494f09ce..b4f64c719 100644
--- a/lib/cfm.c
+++ b/lib/cfm.c
@@ -40,6 +40,9 @@ VLOG_DEFINE_THIS_MODULE(cfm);
 
 /* Ethernet destination address of CCM packets. */
 static const uint8_t eth_addr_ccm[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x30 };
+static const uint8_t eth_addr_ccm_x[6] = {
+    0x01, 0x23, 0x20, 0x00, 0x00, 0x30
+};
 
 #define ETH_TYPE_CFM 0x8902
 
@@ -67,6 +70,7 @@ struct cfm {
     struct hmap_node hmap_node; /* Node in all_cfms list. */
 
     uint16_t mpid;
+    bool extended;         /* Extended mode. */
     bool fault;            /* Indicates connectivity fault. */
     bool unexpected_recv;  /* Received an unexpected CCM. */
 
@@ -98,6 +102,12 @@ static struct hmap all_cfms = HMAP_INITIALIZER(&all_cfms);
 static void cfm_unixctl_show(struct unixctl_conn *, const char *args,
                              void *aux);
 
+static const uint8_t *
+cfm_ccm_addr(const struct cfm *cfm)
+{
+    return cfm->extended ? eth_addr_ccm_x : eth_addr_ccm;
+}
+
 static void
 cfm_generate_maid(struct cfm *cfm)
 {
@@ -297,8 +307,7 @@ cfm_compose_ccm(struct cfm *cfm, struct ofpbuf *packet,
     struct ccm *ccm;
 
     timer_set_duration(&cfm->tx_timer, cfm->ccm_interval_ms);
-
-    ccm = eth_compose(packet, eth_addr_ccm, eth_src, ETH_TYPE_CFM,
+    ccm = eth_compose(packet, cfm_ccm_addr(cfm), eth_src, ETH_TYPE_CFM,
                       sizeof *ccm);
     ccm->mdlevel_version = 0;
     ccm->opcode = CCM_OPCODE;
@@ -333,6 +342,7 @@ cfm_configure(struct cfm *cfm, const struct cfm_settings *s)
     }
 
     cfm->mpid = s->mpid;
+    cfm->extended = s->extended;
     interval = ms_to_ccm_interval(s->interval);
 
     if (interval != cfm->ccm_interval) {
@@ -346,12 +356,12 @@ cfm_configure(struct cfm *cfm, const struct cfm_settings *s)
     return true;
 }
 
-/* Returns true if the CFM library should process packets from 'flow'. */
+/* Returns true if 'cfm' should process packets from 'flow'. */
 bool
-cfm_should_process_flow(const struct flow *flow)
+cfm_should_process_flow(const struct cfm *cfm, const struct flow *flow)
 {
     return (ntohs(flow->dl_type) == ETH_TYPE_CFM
-            && eth_addr_equals(flow->dl_dst, eth_addr_ccm));
+            && eth_addr_equals(flow->dl_dst, cfm_ccm_addr(cfm)));
 }
 
 /* Updates internal statistics relevant to packet 'p'.  Should be called on
diff --git a/lib/cfm.h b/lib/cfm.h
index 659077b47..0d1ddb2f0 100644
--- a/lib/cfm.h
+++ b/lib/cfm.h
@@ -27,6 +27,7 @@ struct ofpbuf;
 struct cfm_settings {
     uint16_t mpid;              /* The MPID of this CFM. */
     int interval;               /* The requested transmission interval. */
+    bool extended;              /* Run in extended mode. */
 };
 
 void cfm_init(void);
@@ -37,7 +38,7 @@ bool cfm_should_send_ccm(struct cfm *);
 void cfm_compose_ccm(struct cfm *, struct ofpbuf *packet, uint8_t eth_src[6]);
 void cfm_wait(struct cfm *);
 bool cfm_configure(struct cfm *, const struct cfm_settings *);
-bool cfm_should_process_flow(const struct flow *);
+bool cfm_should_process_flow(const struct cfm *cfm, const struct flow *);
 void cfm_process_heartbeat(struct cfm *, const struct ofpbuf *packet);
 bool cfm_get_fault(const struct cfm *);
 
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index c84456bc1..9a7132141 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1620,7 +1620,7 @@ process_special(struct ofproto_dpif *ofproto, const struct flow *flow,
         return false;
     }
 
-    if (ofport->cfm && cfm_should_process_flow(flow)) {
+    if (ofport->cfm && cfm_should_process_flow(ofport->cfm, flow)) {
         if (packet) {
             cfm_process_heartbeat(ofport->cfm, packet);
         }
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index e903a808c..44b5fbe94 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2606,6 +2606,7 @@ static void
 iface_configure_cfm(struct iface *iface)
 {
     const struct ovsrec_interface *cfg = iface->cfg;
+    const char *extended_str;
     struct cfm_settings s;
 
     if (!cfg->n_cfm_mpid) {
@@ -2620,6 +2621,10 @@ iface_configure_cfm(struct iface *iface)
         s.interval = 1000;
     }
 
+    extended_str = get_interface_other_config(iface->cfg, "cfm_extended",
+                                              "false");
+    s.extended = !strcasecmp("true", extended_str);
+
     ofproto_port_set_cfm(iface->port->bridge->ofproto, iface->ofp_port, &s);
 }
 
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index b974a3d02..5151fea21 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -1425,6 +1425,11 @@
           <dd> The transmission interval of CFM heartbeats in milliseconds.
             Three missed heartbeat receptions indicate a connectivity fault.
             Defaults to 1000ms. </dd>
+          <dt><code>cfm_extended</code></dt>
+          <dd> When true, the CFM module operates in extended mode. This causes
+            it to use a nonstandard destination address to avoid conflicting
+            with compliant implementations which may be running concurrently on
+            the network. Defaults to false. </dd>
           <dt><code>bond-stable-id</code></dt>
           <dd> A positive integer using in <code>stable</code> bond mode to
             make slave selection decisions.  Allocating