[OpenWrt-Devel] [PATCH] netifd: Do not add local/source policy rules multiple times

[Kristian Evensen]

From: Kristian Evensen <kristian.evensen at gmail.com>

interface_ip_set_enabled() is usually called two times right after one another,
once to handle config_ip and once to handle proto_ip. As long as
ip->iface->l3_dev.dev is set, the local/source policy rules are updated.

This value is in several cases set on both config_ip and proto_ip, causing the
rules to be added multiple time. The reason is that the kernel does not respect
the NLM_F_* flag for rules. In other words, the rule state has to be managed by
the routing daemon.

Since the local/source policy rules are bound to iface, this commit solves the
problem by adding a flag to interface which stores the current rule state. The
flag follows the enabled-paramter passed to interface_ip_set_enabled(), similar
to route-> and addr->enabled. The flag breaks the alignment of the interface
struct, but based on earlier commits this seems to be ok.

I have tested the patch in different configurations and have not found any
regression.

Signed-off-by: Kristian Evensen <kristian.evensen at gmail.com>
---
 interface-ip.c | 4 +++-
 interface.h    | 1 +
 system-linux.c | 4 +---
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/interface-ip.c b/interface-ip.c
index 1e085bc..b96d98c 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -1289,12 +1289,14 @@ void interface_ip_set_enabled(struct interface_ip_settings *ip, bool enabled)
 			if (!strcmp(a->name, ip->iface->name))
 				interface_set_prefix_address(a, c, ip->iface, enabled);
 
-	if (ip->iface && ip->iface->l3_dev.dev) {
+	if (ip->iface && ip->iface->policy_rules_set != enabled &&
+	    ip->iface->l3_dev.dev) {
 		set_ip_lo_policy(enabled, true, ip->iface);
 		set_ip_lo_policy(enabled, false, ip->iface);
 
 		set_ip_source_policy(enabled, true, IPRULE_PRIORITY_REJECT + ip->iface->l3_dev.dev->ifindex,
 			NULL, 0, 0, ip->iface, "failed_policy");
+		ip->iface->policy_rules_set = enabled;
 	}
 }
 
diff --git a/interface.h b/interface.h
index c2049f1..73a3b55 100644
--- a/interface.h
+++ b/interface.h
@@ -112,6 +112,7 @@ struct interface {
 	bool link_state;
 	bool force_link;
 	bool dynamic;
+	bool policy_rules_set;
 
 	time_t start_time;
 	enum interface_state state;
diff --git a/system-linux.c b/system-linux.c
index d3bb64d..2b17764 100644
--- a/system-linux.c
+++ b/system-linux.c
@@ -1792,10 +1792,8 @@ static int system_iprule(struct iprule *rule, int cmd)
 		.rtm_flags = 0,
 	};
 
-	if (cmd == RTM_NEWRULE) {
+	if (cmd == RTM_NEWRULE)
 		rtm.rtm_type = RTN_UNICAST;
-		rtm.rtm_flags |= NLM_F_REPLACE | NLM_F_EXCL;
-	}
 
 	if (rule->invert)
 		rtm.rtm_flags |= FIB_RULE_INVERT;
-- 
1.9.1
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