[RFC,net-next,14/27] ipv6: Handle all fib6_nh in a nexthop in exception handling

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 680d61b65647..49d58ad9f76e 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1747,9 +1747,22 @@  static void fib6_nh_flush_exceptions(struct fib6_nh *nh, struct fib6_info *from)
 	spin_unlock_bh(&rt6_exception_lock);
 }
 
+static int rt6_nh_flush_exceptions(struct fib6_nh *nh, void *arg)
+{
+	struct fib6_info *f6i = arg;
+
+	fib6_nh_flush_exceptions(nh, f6i);
+
+	return 0;
+}
+
 void rt6_flush_exceptions(struct fib6_info *f6i)
 {
-	fib6_nh_flush_exceptions(f6i->fib6_nh, f6i);
+	if (f6i->nh)
+		nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_flush_exceptions,
+					 f6i);
+	else
+		fib6_nh_flush_exceptions(f6i->fib6_nh, f6i);
 }
 
 /* Find cached rt in the hash table inside passed in rt
@@ -1836,6 +1849,24 @@  static int fib6_nh_remove_exception(const struct fib6_nh *nh, int plen,
 	return err;
 }
 
+struct fib6_nh_excptn_arg {
+	struct rt6_info	*rt;
+	int		plen;
+	bool		found;
+};
+
+static int rt6_nh_remove_exception_rt(struct fib6_nh *nh, void *_arg)
+{
+	struct fib6_nh_excptn_arg *arg = _arg;
+	int err;
+
+	err = fib6_nh_remove_exception(nh, arg->plen, arg->rt);
+	if (err == 0)
+		arg->found = true;
+
+	return 0;
+}
+
 static int rt6_remove_exception_rt(struct rt6_info *rt)
 {
 	struct fib6_info *from;
@@ -1844,6 +1875,17 @@  static int rt6_remove_exception_rt(struct rt6_info *rt)
 	if (!from || !(rt->rt6i_flags & RTF_CACHE))
 		return -EINVAL;
 
+	if (from->nh) {
+		struct fib6_nh_excptn_arg arg = {
+			.rt = rt,
+			.plen = from->fib6_src.plen
+		};
+
+		nexthop_for_each_fib6_nh(from->nh, rt6_nh_remove_exception_rt,
+					 &arg);
+		return arg.found ? 0 : -ENOENT;
+	}
+
 	return fib6_nh_remove_exception(from->fib6_nh,
 					from->fib6_src.plen, rt);
 }
@@ -1874,9 +1916,33 @@  static void fib6_nh_update_exception(const struct fib6_nh *nh, int plen,
 		rt6_ex->stamp = jiffies;
 }
 
+struct fib6_nh_match_arg {
+	const struct net_device *dev;
+	const struct in6_addr	*gw;
+	struct fib6_nh		*match;
+};
+
+/* determine if fib6_nh has given device and gateway */
+static int fib6_nh_find_match(struct fib6_nh *nh, void *_arg)
+{
+	struct fib6_nh_match_arg *arg = _arg;
+
+	if (arg->dev != nh->fib_nh_dev ||
+	    (arg->gw && !nh->fib_nh_gw_family) ||
+	    (!arg->gw && nh->fib_nh_gw_family) ||
+	    (arg->gw && !ipv6_addr_equal(arg->gw, &nh->fib_nh_gw6)))
+		return 0;
+
+	arg->match = nh;
+
+	/* found a match, break the loop */
+	return 1;
+}
+
 static void rt6_update_exception_stamp_rt(struct rt6_info *rt)
 {
 	struct fib6_info *from;
+	struct fib6_nh *fib6_nh;
 
 	rcu_read_lock();
 
@@ -1884,7 +1950,21 @@  static void rt6_update_exception_stamp_rt(struct rt6_info *rt)
 	if (!from || !(rt->rt6i_flags & RTF_CACHE))
 		goto unlock;
 
-	fib6_nh_update_exception(from->fib6_nh, from->fib6_src.plen, rt);
+	if (from->nh) {
+		struct fib6_nh_match_arg arg = {
+			.dev = rt->dst.dev,
+			.gw = &rt->rt6i_gateway,
+		};
+
+		nexthop_for_each_fib6_nh(from->nh, fib6_nh_find_match, &arg);
+
+		if (!arg.match)
+			return;
+		fib6_nh = arg.match;
+	} else {
+		fib6_nh = from->fib6_nh;
+	}
+	fib6_nh_update_exception(fib6_nh, from->fib6_src.plen, rt);
 unlock:
 	rcu_read_unlock();
 }
@@ -2046,11 +2126,34 @@  static void fib6_nh_age_exceptions(const struct fib6_nh *nh,
 	rcu_read_unlock_bh();
 }
 
+struct fib6_nh_age_excptn_arg {
+	struct fib6_gc_args	*gc_args;
+	unsigned long		now;
+};
+
+static int rt6_nh_age_exceptions(struct fib6_nh *nh, void *_arg)
+{
+	struct fib6_nh_age_excptn_arg *arg = _arg;
+
+	fib6_nh_age_exceptions(nh, arg->gc_args, arg->now);
+	return 0;
+}
+
 void rt6_age_exceptions(struct fib6_info *f6i,
 			struct fib6_gc_args *gc_args,
 			unsigned long now)
 {
-	fib6_nh_age_exceptions(f6i->fib6_nh, gc_args, now);
+	if (f6i->nh) {
+		struct fib6_nh_age_excptn_arg arg = {
+			.gc_args = gc_args,
+			.now = now
+		};
+
+		nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_age_exceptions,
+					 &arg);
+	} else {
+		fib6_nh_age_exceptions(f6i->fib6_nh, gc_args, now);
+	}
 }
 
 /* must be called with rcu lock held */