Merge branch 'fib_rules-fix-iif-oif-matching-on-l3-master-device'

Ido Schimmel says:

====================
fib_rules: Fix iif / oif matching on L3 master device

Patch #1 fixes a recently reported regression regarding FIB rules that
match on iif / oif being a VRF device.

Patch #2 adds test cases to the FIB rules selftest.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

include/net/fib_rules.h

@@ -45,6 +45,8 @@ struct fib_rule {
 	struct fib_rule_port_range	dport_range;
 	u16			sport_mask;
 	u16			dport_mask;
+	u8                      iif_is_l3_master;
+	u8                      oif_is_l3_master;
 	struct rcu_head		rcu;
 };
 

include/net/flow.h

@@ -38,6 +38,7 @@ struct flowi_common {
 	__u8	flowic_flags;
 #define FLOWI_FLAG_ANYSRC		0x01
 #define FLOWI_FLAG_KNOWN_NH		0x02
+#define FLOWI_FLAG_L3MDEV_OIF		0x04
 	__u32	flowic_secid;
 	kuid_t  flowic_uid;
 	__u32		flowic_multipath_hash;

include/net/l3mdev.h

@@ -59,6 +59,20 @@ int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type, struct net *net,
 int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 			  struct fib_lookup_arg *arg);
 
+static inline
+bool l3mdev_fib_rule_iif_match(const struct flowi *fl, int iifindex)
+{
+	return !(fl->flowi_flags & FLOWI_FLAG_L3MDEV_OIF) &&
+	       fl->flowi_l3mdev == iifindex;
+}
+
+static inline
+bool l3mdev_fib_rule_oif_match(const struct flowi *fl, int oifindex)
+{
+	return fl->flowi_flags & FLOWI_FLAG_L3MDEV_OIF &&
+	       fl->flowi_l3mdev == oifindex;
+}
+
 void l3mdev_update_flow(struct net *net, struct flowi *fl);
 
 int l3mdev_master_ifindex_rcu(const struct net_device *dev);
@@ -327,6 +341,19 @@ int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 {
 	return 1;
 }
+
+static inline
+bool l3mdev_fib_rule_iif_match(const struct flowi *fl, int iifindex)
+{
+	return false;
+}
+
+static inline
+bool l3mdev_fib_rule_oif_match(const struct flowi *fl, int oifindex)
+{
+	return false;
+}
+
 static inline
 void l3mdev_update_flow(struct net *net, struct flowi *fl)
 {

net/core/fib_rules.c

@@ -257,18 +257,36 @@ static int nla_put_port_range(struct sk_buff *skb, int attrtype,
 	return nla_put(skb, attrtype, sizeof(*range), range);
 }
 
+static bool fib_rule_iif_match(const struct fib_rule *rule, int iifindex,
+			       const struct flowi *fl)
+{
+	u8 iif_is_l3_master = READ_ONCE(rule->iif_is_l3_master);
+
+	return iif_is_l3_master ? l3mdev_fib_rule_iif_match(fl, iifindex) :
+				  fl->flowi_iif == iifindex;
+}
+
+static bool fib_rule_oif_match(const struct fib_rule *rule, int oifindex,
+			       const struct flowi *fl)
+{
+	u8 oif_is_l3_master = READ_ONCE(rule->oif_is_l3_master);
+
+	return oif_is_l3_master ? l3mdev_fib_rule_oif_match(fl, oifindex) :
+				  fl->flowi_oif == oifindex;
+}
+
 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
 			  struct flowi *fl, int flags,
 			  struct fib_lookup_arg *arg)
 {
 	int iifindex, oifindex, ret = 0;
 
 	iifindex = READ_ONCE(rule->iifindex);
-	if (iifindex && (iifindex != fl->flowi_iif))
+	if (iifindex && !fib_rule_iif_match(rule, iifindex, fl))
 		goto out;
 
 	oifindex = READ_ONCE(rule->oifindex);
-	if (oifindex && (oifindex != fl->flowi_oif))
+	if (oifindex && !fib_rule_oif_match(rule, oifindex, fl))
 		goto out;
 
 	if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
@@ -736,16 +754,20 @@ static int fib_nl2rule_rtnl(struct fib_rule *nlrule,
 		struct net_device *dev;
 
 		dev = __dev_get_by_name(nlrule->fr_net, nlrule->iifname);
-		if (dev)
+		if (dev) {
 			nlrule->iifindex = dev->ifindex;
+			nlrule->iif_is_l3_master = netif_is_l3_master(dev);
+		}
 	}
 
 	if (tb[FRA_OIFNAME]) {
 		struct net_device *dev;
 
 		dev = __dev_get_by_name(nlrule->fr_net, nlrule->oifname);
-		if (dev)
+		if (dev) {
 			nlrule->oifindex = dev->ifindex;
+			nlrule->oif_is_l3_master = netif_is_l3_master(dev);
+		}
 	}
 
 	return 0;
@@ -1336,11 +1358,17 @@ static void attach_rules(struct list_head *rules, struct net_device *dev)
 
 	list_for_each_entry(rule, rules, list) {
 		if (rule->iifindex == -1 &&
-		    strcmp(dev->name, rule->iifname) == 0)
+		    strcmp(dev->name, rule->iifname) == 0) {
 			WRITE_ONCE(rule->iifindex, dev->ifindex);
+			WRITE_ONCE(rule->iif_is_l3_master,
+				   netif_is_l3_master(dev));
+		}
 		if (rule->oifindex == -1 &&
-		    strcmp(dev->name, rule->oifname) == 0)
+		    strcmp(dev->name, rule->oifname) == 0) {
 			WRITE_ONCE(rule->oifindex, dev->ifindex);
+			WRITE_ONCE(rule->oif_is_l3_master,
+				   netif_is_l3_master(dev));
+		}
 	}
 }
 
@@ -1349,10 +1377,14 @@ static void detach_rules(struct list_head *rules, struct net_device *dev)
 	struct fib_rule *rule;
 
 	list_for_each_entry(rule, rules, list) {
-		if (rule->iifindex == dev->ifindex)
+		if (rule->iifindex == dev->ifindex) {
 			WRITE_ONCE(rule->iifindex, -1);
-		if (rule->oifindex == dev->ifindex)
+			WRITE_ONCE(rule->iif_is_l3_master, false);
+		}
+		if (rule->oifindex == dev->ifindex) {
 			WRITE_ONCE(rule->oifindex, -1);
+			WRITE_ONCE(rule->oif_is_l3_master, false);
+		}
 	}
 }
 

net/l3mdev/l3mdev.c

@@ -277,8 +277,10 @@ void l3mdev_update_flow(struct net *net, struct flowi *fl)
 	if (fl->flowi_oif) {
 		dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 		if (dev) {
-			if (!fl->flowi_l3mdev)
+			if (!fl->flowi_l3mdev) {
 				fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
+				fl->flowi_flags |= FLOWI_FLAG_L3MDEV_OIF;
+			}
 
 			/* oif set to L3mdev directs lookup to its table;
 			 * reset to avoid oif match in fib_lookup

tools/testing/selftests/net/fib_rule_tests.sh

@@ -359,6 +359,23 @@ fib_rule6_test()
 			"$getnomatch" "iif flowlabel masked redirect to table" \
 			"iif flowlabel masked no redirect to table"
 	fi
+
+	$IP link show dev $DEV | grep -q vrf0
+	if [ $? -eq 0 ]; then
+		match="oif vrf0"
+		getmatch="oif $DEV"
+		getnomatch="oif lo"
+		fib_rule6_test_match_n_redirect "$match" "$getmatch" \
+			"$getnomatch" "VRF oif redirect to table" \
+			"VRF oif no redirect to table"
+
+		match="from $SRC_IP6 iif vrf0"
+		getmatch="from $SRC_IP6 iif $DEV"
+		getnomatch="from $SRC_IP6 iif lo"
+		fib_rule6_test_match_n_redirect "$match" "$getmatch" \
+			"$getnomatch" "VRF iif redirect to table" \
+			"VRF iif no redirect to table"
+	fi
 }
 
 fib_rule6_vrf_test()
@@ -635,6 +652,23 @@ fib_rule4_test()
 			"$getnomatch" "iif dscp masked redirect to table" \
 			"iif dscp masked no redirect to table"
 	fi
+
+	$IP link show dev $DEV | grep -q vrf0
+	if [ $? -eq 0 ]; then
+		match="oif vrf0"
+		getmatch="oif $DEV"
+		getnomatch="oif lo"
+		fib_rule4_test_match_n_redirect "$match" "$getmatch" \
+			"$getnomatch" "VRF oif redirect to table" \
+			"VRF oif no redirect to table"
+
+		match="from $SRC_IP iif vrf0"
+		getmatch="from $SRC_IP iif $DEV"
+		getnomatch="from $SRC_IP iif lo"
+		fib_rule4_test_match_n_redirect "$match" "$getmatch" \
+			"$getnomatch" "VRF iif redirect to table" \
+			"VRF iif no redirect to table"
+	fi
 }
 
 fib_rule4_vrf_test()