ipv6: Pass fib6_result to fib lookups

Change fib6_lookup and fib6_table_lookup to take a fib6_result and set
f6i and nh rather than returning a fib6_info. For now both always
return 0.

A later patch set can make these more like the IPv4 counterparts and
return EINVAL, EACCESS, etc based on fib6_type.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_fib.h

@@ -389,12 +389,13 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 /* called with rcu lock held; can return error pointer
  * caller needs to select path
  */
-struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			      int flags);
+int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+		struct fib6_result *res, int flags);
 
 /* called with rcu lock held; caller needs to select path */
-struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
-				    int oif, struct flowi6 *fl6, int strict);
+int fib6_table_lookup(struct net *net, struct fib6_table *table,
+		      int oif, struct flowi6 *fl6, struct fib6_result *res,
+		      int strict);
 
 void fib6_select_path(const struct net *net, struct fib6_result *res,
 		      struct flowi6 *fl6, int oif, bool have_oif_match,

include/net/ipv6_stubs.h

@@ -29,12 +29,11 @@ struct ipv6_stub {
 	int (*ipv6_route_input)(struct sk_buff *skb);
 
 	struct fib6_table *(*fib6_get_table)(struct net *net, u32 id);
-	struct fib6_info *(*fib6_lookup)(struct net *net, int oif,
-					 struct flowi6 *fl6, int flags);
-	struct fib6_info *(*fib6_table_lookup)(struct net *net,
-					      struct fib6_table *table,
+	int (*fib6_lookup)(struct net *net, int oif, struct flowi6 *fl6,
+			   struct fib6_result *res, int flags);
+	int (*fib6_table_lookup)(struct net *net, struct fib6_table *table,
 				 int oif, struct flowi6 *fl6,
-					      int flags);
+				 struct fib6_result *res, int flags);
 	void (*fib6_select_path)(const struct net *net, struct fib6_result *res,
 				 struct flowi6 *fl6, int oif, bool oif_match,
 				 const struct sk_buff *skb, int strict);

net/core/filter.c

@@ -4684,7 +4684,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 	struct inet6_dev *idev;
 	struct flowi6 fl6;
 	int strict = 0;
-	int oif;
+	int oif, err;
 	u32 mtu;
 
 	/* link local addresses are never forwarded */
@@ -4726,7 +4726,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 		if (unlikely(!tb))
 			return BPF_FIB_LKUP_RET_NOT_FWDED;
 
-		res.f6i = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6,
+		err = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6, &res,
 						   strict);
 	} else {
 		fl6.flowi6_mark = 0;
@@ -4734,10 +4734,10 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 		fl6.flowi6_tun_key.tun_id = 0;
 		fl6.flowi6_uid = sock_net_uid(net, NULL);
 
-		res.f6i = ipv6_stub->fib6_lookup(net, oif, &fl6, strict);
+		err = ipv6_stub->fib6_lookup(net, oif, &fl6, &res, strict);
 	}
 
-	if (unlikely(IS_ERR_OR_NULL(res.f6i) ||
+	if (unlikely(err || IS_ERR_OR_NULL(res.f6i) ||
 		     res.f6i == net->ipv6.fib6_null_entry))
 		return BPF_FIB_LKUP_RET_NOT_FWDED;
 

net/ipv6/addrconf_core.c

@@ -144,18 +144,19 @@ static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
 	return NULL;
 }
 
-static struct fib6_info *
+static int
 eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
-			       int oif, struct flowi6 *fl6, int flags)
+			       int oif, struct flowi6 *fl6,
+			       struct fib6_result *res, int flags)
 {
-	return NULL;
+	return -EAFNOSUPPORT;
 }
 
-static struct fib6_info *
+static int
 eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			 int flags)
+			 struct fib6_result *res, int flags)
 {
-	return NULL;
+	return -EAFNOSUPPORT;
 }
 
 static void

net/ipv6/fib6_rules.c

@@ -61,16 +61,16 @@ unsigned int fib6_rules_seq_read(struct net *net)
 }
 
 /* called with rcu lock held; no reference taken on fib6_info */
-struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			      int flags)
+int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+		struct fib6_result *res, int flags)
 {
-	struct fib6_info *f6i;
 	int err;
 
 	if (net->ipv6.fib6_has_custom_rules) {
 		struct fib_lookup_arg arg = {
 			.lookup_ptr = fib6_table_lookup,
 			.lookup_data = &oif,
+			.result = res,
 			.flags = FIB_LOOKUP_NOREF,
 		};
 
@@ -78,19 +78,15 @@ struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 
 		err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
 				       flowi6_to_flowi(fl6), flags, &arg);
-		if (err)
-			return ERR_PTR(err);
-
-		f6i = arg.result ? : net->ipv6.fib6_null_entry;
 	} else {
-		f6i = fib6_table_lookup(net, net->ipv6.fib6_local_tbl,
-					oif, fl6, flags);
-		if (!f6i || f6i == net->ipv6.fib6_null_entry)
-			f6i = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
-						oif, fl6, flags);
+		err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
+					fl6, res, flags);
+		if (err || res->f6i == net->ipv6.fib6_null_entry)
+			err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
+						oif, fl6, res, flags);
 	}
 
-	return f6i;
+	return err;
 }
 
 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
@@ -157,10 +153,10 @@ static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
 				int flags, struct fib_lookup_arg *arg)
 {
+	struct fib6_result *res = arg->result;
 	struct flowi6 *flp6 = &flp->u.ip6;
 	struct net *net = rule->fr_net;
 	struct fib6_table *table;
-	struct fib6_info *f6i;
 	int err = -EAGAIN, *oif;
 	u32 tb_id;
 
@@ -182,14 +178,10 @@ static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
 		return -EAGAIN;
 
 	oif = (int *)arg->lookup_data;
-	f6i = fib6_table_lookup(net, table, *oif, flp6, flags);
-	if (f6i != net->ipv6.fib6_null_entry) {
+	err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
+	if (!err && res->f6i != net->ipv6.fib6_null_entry)
 		err = fib6_rule_saddr(net, rule, flags, flp6,
-				      fib6_info_nh_dev(f6i));
-
-		if (likely(!err))
-			arg->result = f6i;
-	}
+				      res->nh->fib_nh_dev);
 
 	return err;
 }

net/ipv6/ip6_fib.c

@@ -354,10 +354,11 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 }
 
 /* called with rcu lock held; no reference taken on fib6_info */
-struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			      int flags)
+int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+		struct fib6_result *res, int flags)
 {
-	return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6, flags);
+	return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
+				 res, flags);
 }
 
 static void __net_init fib6_tables_init(struct net *net)

net/ipv6/route.c

@@ -1839,11 +1839,10 @@ void rt6_age_exceptions(struct fib6_info *rt,
 }
 
 /* must be called with rcu lock held */
-struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
-				    int oif, struct flowi6 *fl6, int strict)
+int fib6_table_lookup(struct net *net, struct fib6_table *table, int oif,
+		      struct flowi6 *fl6, struct fib6_result *res, int strict)
 {
 	struct fib6_node *fn, *saved_fn;
-	struct fib6_result res;
 
 	fn = fib6_node_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
 	saved_fn = fn;
@@ -1852,8 +1851,8 @@ struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
 		oif = 0;
 
 redo_rt6_select:
-	rt6_select(net, fn, oif, &res, strict);
-	if (res.f6i == net->ipv6.fib6_null_entry) {
+	rt6_select(net, fn, oif, res, strict);
+	if (res->f6i == net->ipv6.fib6_null_entry) {
 		fn = fib6_backtrack(fn, &fl6->saddr);
 		if (fn)
 			goto redo_rt6_select;
@@ -1865,9 +1864,9 @@ struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
 		}
 	}
 
-	trace_fib6_table_lookup(net, &res, table, fl6);
+	trace_fib6_table_lookup(net, res, table, fl6);
 
-	return res.f6i;
+	return 0;
 }
 
 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
@@ -1885,7 +1884,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
 
 	rcu_read_lock();
 
-	res.f6i = fib6_table_lookup(net, table, oif, fl6, strict);
+	fib6_table_lookup(net, table, oif, fl6, &res, strict);
 	if (res.f6i == net->ipv6.fib6_null_entry) {
 		rt = net->ipv6.ip6_null_entry;
 		rcu_read_unlock();