tc: policing requires a rate estimator

Found that while trying average rate policing, it was possible to
request average rate policing without a rate estimator. This results
in no policing which is harmless but incorrect.

Since policing could be setup in two steps, need to check
in the kernel.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 34 insertions, 3 deletions

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 8cd8185fa2ed..dcf5bfa7d4f1 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -45,5 +45,6 @@ extern void gen_kill_estimator(struct gnet_stats_basic *bstats,
 extern int gen_replace_estimator(struct gnet_stats_basic *bstats,
                                  struct gnet_stats_rate_est *rate_est,
                                  spinlock_t *stats_lock, struct nlattr *opt);
+extern int gen_estimator_active(const struct gnet_stats_rate_est *rate_est);
 
 #endif
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 80aa160877e9..3885550f0187 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -242,6 +242,7 @@ int gen_new_estimator(struct gnet_stats_basic *bstats,
 
         return 0;
 }
+EXPORT_SYMBOL(gen_new_estimator);
 
 static void __gen_kill_estimator(struct rcu_head *head)
 {
@@ -275,6 +276,7 @@ void gen_kill_estimator(struct gnet_stats_basic *bstats,
                 call_rcu(&e->e_rcu, __gen_kill_estimator);
         }
 }
+EXPORT_SYMBOL(gen_kill_estimator);
 
 /**
  * gen_replace_estimator - replace rate estimator configuration
@@ -295,8 +297,30 @@ int gen_replace_estimator(struct gnet_stats_basic *bstats,
         gen_kill_estimator(bstats, rate_est);
         return gen_new_estimator(bstats, rate_est, stats_lock, opt);
 }
+EXPORT_SYMBOL(gen_replace_estimator);
+
+/**
+ * gen_estimator_active - test if estimator is currently in use
+ * @rate_est: rate estimator statistics
+ *
+ * Returns 1 if estimator is active, and 0 if not.
+ */
+int gen_estimator_active(const struct gnet_stats_rate_est *rate_est)
+{
+        int idx;
+        struct gen_estimator *e;
 
+        ASSERT_RTNL();
 
-EXPORT_SYMBOL(gen_kill_estimator);
-EXPORT_SYMBOL(gen_new_estimator);
-EXPORT_SYMBOL(gen_replace_estimator);
+        for (idx=0; idx <= EST_MAX_INTERVAL; idx++) {
+                if (!elist[idx].timer.function)
+                        continue;
+
+                list_for_each_entry(e, &elist[idx].list, list) {
+                        if (e->rate_est == rate_est)
+                                return 1;
+                }
+        }
+        return 0;
+}
+EXPORT_SYMBOL(gen_estimator_active);
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index e19a0261144a..c39f60cea6ee 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -182,6 +182,12 @@ override:
                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
                 if (R_tab == NULL)
                         goto failure;
+
+                if (!est && !gen_estimator_active(&police->tcf_rate_est)) {
+                        err = -EINVAL;
+                        goto failure;
+                }
+
                 if (parm->peakrate.rate) {
                         P_tab = qdisc_get_rtab(&parm->peakrate,
                                                tb[TCA_POLICE_PEAKRATE]);