commit 73417f617a93cf30342c3ea41abc38927bd467aa
author Thomas Graf <tgraf@suug.ch> Tue Mar 27 13:56:52 2007 -0700
committer David S. Miller <davem@sunset.davemloft.net> Wed Apr 25 22:28:18 2007 -0700
tree 6093005afdca1825197758d851ca5f275d62356f
parent be776281aee54626a474ba06f91926b98bdd180d

[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 <muli@il.ibm.com> for catching a bug
in the previous patch.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/fib_rules.h

diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h
index 08bab8b..ed3a887 100644
--- a/include/net/fib_rules.h
+++ b/include/net/fib_rules.h
@@ -59,6 +59,10 @@
 	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;

net/core/fib_rules.c

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 5824b26..cb2dae1 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -44,6 +44,12 @@
 		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 @@
 		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 @@
 		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;
 	}

net/decnet/dn_rules.c

diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
index fd0cc2a..7f58b95 100644
--- 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 @@
 	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 @@
 	.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,

net/ipv4/fib_rules.c

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b021b34..fe29b98 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -298,6 +298,11 @@
 	       + 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 @@
 	.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,