[NET] fib_rules: Flush route cache after rule modifications

The results of FIB rules lookups are cached in the routing cache
except for IPv6 as no such cache exists. So far, it was the
responsibility of the user to flush the cache after modifying any
rules. This lead to many false bug reports due to misunderstanding
of this concept.

This patch automatically flushes the route cache after inserting
or deleting a rule.

Thanks to Muli Ben-Yehuda <[email protected]> for catching a bug
in the previous patch.

Signed-off-by: Thomas Graf <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h
index 08bab8b6e57548a2bb305735280d24ba0d5b5938..ed3a8872c6cafa25f550ba6dcaa2b2d30328d339 100644 (file)
--- a/include/net/fib_rules.h
+++ b/include/net/fib_rules.h
@@ -59,6 +59,10 @@ struct fib_rules_ops
        u32                     (*default_pref)(void);
        size_t                  (*nlmsg_payload)(struct fib_rule *);
 
+       /* Called after modifications to the rules set, must flush
+        * the route cache if one exists. */
+       void                    (*flush_cache)(void);
+
        int                     nlgroup;
        struct nla_policy       *policy;
        struct list_head        *rules_list;

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 5824b2644f26b6d8c3dc4743626b7c1c8050d9dd..cb2dae19531b49cdf66b95b23f268b7de2de596a 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -44,6 +44,12 @@ static void rules_ops_put(struct fib_rules_ops *ops)
                module_put(ops->owner);
 }
 
+static void flush_route_cache(struct fib_rules_ops *ops)
+{
+       if (ops->flush_cache)
+               ops->flush_cache();
+}
+
 int fib_rules_register(struct fib_rules_ops *ops)
 {
        int err = -EEXIST;
@@ -314,6 +320,7 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                list_add_rcu(&rule->list, ops->rules_list);
 
        notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
+       flush_route_cache(ops);
        rules_ops_put(ops);
        return 0;
 
@@ -404,6 +411,7 @@ static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                notify_rule_change(RTM_DELRULE, rule, ops, nlh,
                                   NETLINK_CB(skb).pid);
                fib_rule_put(rule);
+               flush_route_cache(ops);
                rules_ops_put(ops);
                return 0;
        }

diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
index fd0cc2aa316c6018adb007519b7cdc5732f7e61f..7f58b95b27d1e00725d140c701cdb3d1cb408068 100644 (file)
--- a/net/decnet/dn_rules.c
+++ b/net/decnet/dn_rules.c
@@ -31,6 +31,7 @@
 #include <net/dn_fib.h>
 #include <net/dn_neigh.h>
 #include <net/dn_dev.h>
+#include <net/dn_route.h>
 
 static struct fib_rules_ops dn_fib_rules_ops;
 
@@ -239,6 +240,11 @@ static u32 dn_fib_rule_default_pref(void)
        return 0;
 }
 
+static void dn_fib_rule_flush_cache(void)
+{
+       dn_rt_cache_flush(0);
+}
+
 static struct fib_rules_ops dn_fib_rules_ops = {
        .family         = AF_DECnet,
        .rule_size      = sizeof(struct dn_fib_rule),
@@ -249,6 +255,7 @@ static struct fib_rules_ops dn_fib_rules_ops = {
        .compare        = dn_fib_rule_compare,
        .fill           = dn_fib_rule_fill,
        .default_pref   = dn_fib_rule_default_pref,
+       .flush_cache    = dn_fib_rule_flush_cache,
        .nlgroup        = RTNLGRP_DECnet_RULE,
        .policy         = dn_fib_rule_policy,
        .rules_list     = &dn_fib_rules,

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b021b3440ca3f2fc7a6a084a1e40213d018fb4aa..fe29b98d6c8f3b6b9ad08d971db65f05869d4bb3 100644 (file)
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -298,6 +298,11 @@ static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
               + nla_total_size(4); /* flow */
 }
 
+static void fib4_rule_flush_cache(void)
+{
+       rt_cache_flush(0);
+}
+
 static struct fib_rules_ops fib4_rules_ops = {
        .family         = AF_INET,
        .rule_size      = sizeof(struct fib4_rule),
@@ -309,6 +314,7 @@ static struct fib_rules_ops fib4_rules_ops = {
        .fill           = fib4_rule_fill,
        .default_pref   = fib4_rule_default_pref,
        .nlmsg_payload  = fib4_rule_nlmsg_payload,
+       .flush_cache    = fib4_rule_flush_cache,
        .nlgroup        = RTNLGRP_IPV4_RULE,
        .policy         = fib4_rule_policy,
        .rules_list     = &fib4_rules,