ipv6: Handle all fib6_nh in a nexthop in __find_rr_leaf

Add a hook in __find_rr_leaf to handle nexthop struct in a fib6_info.
nexthop_for_each_fib6_nh is used to walk each fib6_nh in a nexthop and
call find_match. On a match, use the fib6_nh saved in the callback arg
to setup fib6_result.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -765,6 +765,24 @@ static bool find_match(struct fib6_nh *nh, u32 fib6_flags,
 	return rc;
 }
 
+struct fib6_nh_frl_arg {
+	u32		flags;
+	int		oif;
+	int		strict;
+	int		*mpri;
+	bool		*do_rr;
+	struct fib6_nh	*nh;
+};
+
+static int rt6_nh_find_match(struct fib6_nh *nh, void *_arg)
+{
+	struct fib6_nh_frl_arg *arg = _arg;
+
+	arg->nh = nh;
+	return find_match(nh, arg->flags, arg->oif, arg->strict,
+			  arg->mpri, arg->do_rr);
+}
+
 static void __find_rr_leaf(struct fib6_info *f6i_start,
 			   struct fib6_info *nomatch, u32 metric,
 			   struct fib6_result *res, struct fib6_info **cont,
@@ -775,6 +793,7 @@ static void __find_rr_leaf(struct fib6_info *f6i_start,
 	for (f6i = f6i_start;
 	     f6i && f6i != nomatch;
 	     f6i = rcu_dereference(f6i->fib6_next)) {
+		bool matched = false;
 		struct fib6_nh *nh;
 
 		if (cont && f6i->fib6_metric != metric) {
@@ -785,8 +804,34 @@ static void __find_rr_leaf(struct fib6_info *f6i_start,
 		if (fib6_check_expired(f6i))
 			continue;
 
-		nh = f6i->fib6_nh;
-		if (find_match(nh, f6i->fib6_flags, oif, strict, mpri, do_rr)) {
+		if (unlikely(f6i->nh)) {
+			struct fib6_nh_frl_arg arg = {
+				.flags  = f6i->fib6_flags,
+				.oif    = oif,
+				.strict = strict,
+				.mpri   = mpri,
+				.do_rr  = do_rr
+			};
+
+			if (nexthop_is_blackhole(f6i->nh)) {
+				res->fib6_flags = RTF_REJECT;
+				res->fib6_type = RTN_BLACKHOLE;
+				res->f6i = f6i;
+				res->nh = nexthop_fib6_nh(f6i->nh);
+				return;
+			}
+			if (nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_find_match,
+						     &arg)) {
+				matched = true;
+				nh = arg.nh;
+			}
+		} else {
+			nh = f6i->fib6_nh;
+			if (find_match(nh, f6i->fib6_flags, oif, strict,
+				       mpri, do_rr))
+				matched = true;
+		}
+		if (matched) {
 			res->f6i = f6i;
 			res->nh = nh;
 			res->fib6_flags = f6i->fib6_flags;