X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=ofproto%2Ffail-open.c;h=04be5ce6a357caf31f7ef88176b60fe7c2ae9b80;hb=5136ce492c414f377f7be9ae32b259abb9f76580;hp=0e88729375f32a8a5e2e8a88e8136fab6376fda9;hpb=8cd4882fd5c3080816a070ad582ef06842f7c482;p=sliver-openvswitch.git

diff --git a/ofproto/fail-open.c b/ofproto/fail-open.c
index 0e8872937..04be5ce6a 100644
--- a/ofproto/fail-open.c
+++ b/ofproto/fail-open.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,65 +21,266 @@
 #include "flow.h"
 #include "mac-learning.h"
 #include "odp-util.h"
+#include "ofp-util.h"
+#include "ofpbuf.h"
 #include "ofproto.h"
+#include "pktbuf.h"
+#include "poll-loop.h"
 #include "rconn.h"
 #include "status.h"
 #include "timeval.h"
-
-#define THIS_MODULE VLM_fail_open
+#include "vconn.h"
 #include "vlog.h"
 
+VLOG_DEFINE_THIS_MODULE(fail_open)
+
+/*
+ * Fail-open mode.
+ *
+ * In fail-open mode, the switch detects when the controller cannot be
+ * contacted or when the controller is dropping switch connections because the
+ * switch does not pass its admission control policy.  In those situations the
+ * switch sets up flows itself using the "normal" action.
+ *
+ * There is a little subtlety to implementation, to properly handle the case
+ * where the controller allows switch connections but drops them a few seconds
+ * later for admission control reasons.  Because of this case, we don't want to
+ * just stop setting up flows when we connect to the controller: if we did,
+ * then new flow setup and existing flows would stop during the duration of
+ * connection to the controller, and thus the whole network would go down for
+ * that period of time.
+ *
+ * So, instead, we add some special cases when we are connected to a
+ * controller, but not yet sure that it has admitted us:
+ *
+ *     - We set up flows immediately ourselves, but simultaneously send out an
+ *       OFPT_PACKET_IN to the controller.  We put a special bogus buffer-id in
+ *       these OFPT_PACKET_IN messages so that duplicate packets don't get sent
+ *       out to the network when the controller replies.
+ *
+ *     - We also send out OFPT_PACKET_IN messages for totally bogus packets
+ *       every so often, in case no real new flows are arriving in the network.
+ *
+ *     - We don't flush the flow table at the time we connect, because this
+ *       could cause network stuttering in a switch with lots of flows or very
+ *       high-bandwidth flows by suddenly throwing lots of packets down to
+ *       userspace.
+ */
+
 struct fail_open {
     struct ofproto *ofproto;
-    struct rconn *controller;
-    int trigger_duration;
+    struct rconn **controllers;
+    size_t n_controllers;
     int last_disconn_secs;
     struct status_category *ss_cat;
+    long long int next_bogus_packet_in;
+    struct rconn_packet_counter *bogus_packet_counter;
 };
 
-/* Causes the switch to enter or leave fail-open mode, if appropriate. */
+static void fail_open_recover(struct fail_open *);
+
+/* Returns the number of seconds of disconnection after which fail-open mode
+ * should activate. */
+static int
+trigger_duration(const struct fail_open *fo)
+{
+    if (!fo->n_controllers) {
+        /* Shouldn't ever arrive here, but if we do, never fail open. */
+        return INT_MAX;
+    } else {
+        /* Otherwise, every controller must have a chance to send an
+         * inactivity probe and reconnect before we fail open, so take the
+         * maximum probe interval and multiply by 3:
+         *
+         *  - The first interval is the idle time before sending an inactivity
+         *    probe.
+         *
+         *  - The second interval is the time allowed for a response to the
+         *    inactivity probe.
+         *
+         *  - The third interval is the time allowed to reconnect after no
+         *    response is received.
+         */
+        int max_probe_interval;
+        size_t i;
+
+        max_probe_interval = 0;
+        for (i = 0; i < fo->n_controllers; i++) {
+            int probe_interval = rconn_get_probe_interval(fo->controllers[i]);
+            max_probe_interval = MAX(max_probe_interval, probe_interval);
+        }
+        return max_probe_interval * 3;
+    }
+}
+
+/* Returns the number of seconds for which all controllers have been
+ * disconnected.  */
+static int
+failure_duration(const struct fail_open *fo)
+{
+    int min_failure_duration;
+    size_t i;
+
+    if (!fo->n_controllers) {
+        return 0;
+    }
+
+    min_failure_duration = INT_MAX;
+    for (i = 0; i < fo->n_controllers; i++) {
+        int failure_duration = rconn_failure_duration(fo->controllers[i]);
+        min_failure_duration = MIN(min_failure_duration, failure_duration);
+    }
+    return min_failure_duration;
+}
+
+/* Returns true if 'fo' is currently in fail-open mode, otherwise false. */
+bool
+fail_open_is_active(const struct fail_open *fo)
+{
+    return fo->last_disconn_secs != 0;
+}
+
+/* Returns true if at least one controller is connected (regardless of whether
+ * those controllers are believed to have authenticated and accepted this
+ * switch), false if none of them are connected. */
+static bool
+any_controller_is_connected(const struct fail_open *fo)
+{
+    size_t i;
+
+    for (i = 0; i < fo->n_controllers; i++) {
+        if (rconn_is_connected(fo->controllers[i])) {
+            return true;
+        }
+    }
+    return false;
+}
+
+/* Returns true if at least one controller is believed to have authenticated
+ * and accepted this switch, false otherwise. */
+static bool
+any_controller_is_admitted(const struct fail_open *fo)
+{
+    size_t i;
+
+    for (i = 0; i < fo->n_controllers; i++) {
+        if (rconn_is_admitted(fo->controllers[i])) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static void
+send_bogus_packet_in(struct fail_open *fo, struct rconn *rconn)
+{
+    uint8_t mac[ETH_ADDR_LEN];
+    struct ofpbuf *opi;
+    struct ofpbuf b;
+
+    /* Compose ofp_packet_in. */
+    ofpbuf_init(&b, 128);
+    eth_addr_nicira_random(mac);
+    compose_benign_packet(&b, "Open vSwitch Controller Probe", 0xa033, mac);
+    opi = make_packet_in(pktbuf_get_null(), OFPP_LOCAL, OFPR_NO_MATCH, &b, 64);
+    ofpbuf_uninit(&b);
+
+    /* Send. */
+    rconn_send_with_limit(rconn, opi, fo->bogus_packet_counter, 1);
+}
+
+static void
+send_bogus_packet_ins(struct fail_open *fo)
+{
+    size_t i;
+
+    for (i = 0; i < fo->n_controllers; i++) {
+        if (rconn_is_connected(fo->controllers[i])) {
+            send_bogus_packet_in(fo, fo->controllers[i]);
+        }
+    }
+}
+
+/* Enter fail-open mode if we should be in it. */
 void
 fail_open_run(struct fail_open *fo)
 {
-    int disconn_secs = rconn_failure_duration(fo->controller);
-    bool open = disconn_secs >= fo->trigger_duration;
-    if (open != (fo->last_disconn_secs != 0)) {
-        if (!open) {
-            flow_t flow;
-
-            VLOG_WARN("No longer in fail-open mode");
-            fo->last_disconn_secs = 0;
+    int disconn_secs = failure_duration(fo);
 
-            memset(&flow, 0, sizeof flow);
-            ofproto_delete_flow(fo->ofproto, &flow, OFPFW_ALL, 70000);
-        } else {
-            VLOG_WARN("Could not connect to controller for %d seconds, "
-                      "failing open", disconn_secs);
+    /* Enter fail-open mode if 'fo' is not in it but should be.  */
+    if (disconn_secs >= trigger_duration(fo)) {
+        if (!fail_open_is_active(fo)) {
+            VLOG_WARN("Could not connect to controller (or switch failed "
+                      "controller's post-connection admission control "
+                      "policy) for %d seconds, failing open", disconn_secs);
             fo->last_disconn_secs = disconn_secs;
 
             /* Flush all OpenFlow and datapath flows.  We will set up our
              * fail-open rule from fail_open_flushed() when
              * ofproto_flush_flows() calls back to us. */
             ofproto_flush_flows(fo->ofproto);
+        } else if (disconn_secs > fo->last_disconn_secs + 60) {
+            VLOG_INFO("Still in fail-open mode after %d seconds disconnected "
+                      "from controller", disconn_secs);
+            fo->last_disconn_secs = disconn_secs;
         }
-    } else if (open && disconn_secs > fo->last_disconn_secs + 60) {
-        VLOG_INFO("Still in fail-open mode after %d seconds disconnected "
-                  "from controller", disconn_secs);
-        fo->last_disconn_secs = disconn_secs;
     }
+
+    /* Schedule a bogus packet-in if we're connected and in fail-open. */
+    if (fail_open_is_active(fo)) {
+        if (any_controller_is_connected(fo)) {
+            bool expired = time_msec() >= fo->next_bogus_packet_in;
+            if (expired) {
+                send_bogus_packet_ins(fo);
+            }
+            if (expired || fo->next_bogus_packet_in == LLONG_MAX) {
+                fo->next_bogus_packet_in = time_msec() + 2000;
+            }
+        } else {
+            fo->next_bogus_packet_in = LLONG_MAX;
+        }
+    }
+
 }
 
+/* If 'fo' is currently in fail-open mode and its rconn has connected to the
+ * controller, exits fail open mode. */
 void
-fail_open_wait(struct fail_open *fo UNUSED)
+fail_open_maybe_recover(struct fail_open *fo)
 {
-    /* Nothing to do. */
+    if (any_controller_is_admitted(fo)) {
+        fail_open_recover(fo);
+    }
+}
+
+static void
+fail_open_recover(struct fail_open *fo)
+{
+    if (fail_open_is_active(fo)) {
+        flow_t flow;
+
+        VLOG_WARN("No longer in fail-open mode");
+        fo->last_disconn_secs = 0;
+        fo->next_bogus_packet_in = LLONG_MAX;
+
+        memset(&flow, 0, sizeof flow);
+        ofproto_delete_flow(fo->ofproto, &flow, OVSFW_ALL, FAIL_OPEN_PRIORITY);
+    }
+}
+
+void
+fail_open_wait(struct fail_open *fo)
+{
+    if (fo->next_bogus_packet_in != LLONG_MAX) {
+        poll_timer_wait_until(fo->next_bogus_packet_in);
+    }
 }
 
 void
 fail_open_flushed(struct fail_open *fo)
 {
-    int disconn_secs = rconn_failure_duration(fo->controller);
-    bool open = disconn_secs >= fo->trigger_duration;
+    int disconn_secs = failure_duration(fo);
+    bool open = disconn_secs >= trigger_duration(fo);
     if (open) {
         union ofp_action action;
         flow_t flow;
@@ -91,7 +292,7 @@ fail_open_flushed(struct fail_open *fo)
         action.output.len = htons(sizeof action);
         action.output.port = htons(OFPP_NORMAL);
         memset(&flow, 0, sizeof flow);
-        ofproto_add_flow(fo->ofproto, &flow, OFPFW_ALL, 70000,
+        ofproto_add_flow(fo->ofproto, &flow, OVSFW_ALL, FAIL_OPEN_PRIORITY,
                          &action, 1, 0);
     }
 }
@@ -100,41 +301,61 @@ static void
 fail_open_status_cb(struct status_reply *sr, void *fo_)
 {
     struct fail_open *fo = fo_;
-    int cur_duration = rconn_failure_duration(fo->controller);
+    int cur_duration = failure_duration(fo);
+    int trigger = trigger_duration(fo);
 
-    status_reply_put(sr, "trigger-duration=%d", fo->trigger_duration);
+    status_reply_put(sr, "trigger-duration=%d", trigger);
     status_reply_put(sr, "current-duration=%d", cur_duration);
     status_reply_put(sr, "triggered=%s",
-                     cur_duration >= fo->trigger_duration ? "true" : "false");
+                     cur_duration >= trigger ? "true" : "false");
 }
 
+/* Creates and returns a new struct fail_open for 'ofproto', registering switch
+ * status with 'switch_status'.
+ *
+ * The caller should register its set of controllers with
+ * fail_open_set_controllers().  (There should be at least one controller,
+ * otherwise there isn't any point in having the struct fail_open around.) */
 struct fail_open *
-fail_open_create(struct ofproto *ofproto,
-                 int trigger_duration, struct switch_status *switch_status,
-                 struct rconn *controller)
+fail_open_create(struct ofproto *ofproto, struct switch_status *switch_status)
 {
     struct fail_open *fo = xmalloc(sizeof *fo);
     fo->ofproto = ofproto;
-    fo->controller = controller;
-    fo->trigger_duration = trigger_duration;
+    fo->controllers = NULL;
+    fo->n_controllers = 0;
     fo->last_disconn_secs = 0;
     fo->ss_cat = switch_status_register(switch_status, "fail-open",
                                         fail_open_status_cb, fo);
+    fo->next_bogus_packet_in = LLONG_MAX;
+    fo->bogus_packet_counter = rconn_packet_counter_create();
     return fo;
 }
 
+/* Registers the 'n' rconns in 'rconns' as connections to the controller for
+ * 'fo'.  The caller must ensure that all of the rconns remain valid until 'fo'
+ * is destroyed or a new set is registered in a subsequent call.
+ *
+ * Takes ownership of the 'rconns' array, but not of the rconns that it points
+ * to (of which the caller retains ownership). */
 void
-fail_open_set_trigger_duration(struct fail_open *fo, int trigger_duration)
+fail_open_set_controllers(struct fail_open *fo,
+                          struct rconn **rconns, size_t n)
 {
-    fo->trigger_duration = trigger_duration;
+    free(fo->controllers);
+    fo->controllers = rconns;
+    fo->n_controllers = n;
 }
 
+/* Destroys 'fo'. */
 void
 fail_open_destroy(struct fail_open *fo)
 {
     if (fo) {
-        /* We don't own fo->controller. */
+        fail_open_recover(fo);
+        free(fo->controllers);
+        /* We don't own the rconns behind fo->controllers. */
         switch_status_unregister(fo->ss_cat);
+        rconn_packet_counter_destroy(fo->bogus_packet_counter);
         free(fo);
     }
 }