Merge branch 'ipv6-Use-fib6_result-for-fib_lookups'

David Ahern says:

====================
ipv6: Use fib6_result for fib_lookups

Add fib6_result as a single data structure to hold results from a fib
lookup. IPv6 currently has everything in 1 data structure - a fib6_info,
but with nexthop objects the fib6_nh can be in a nexthop or a nexthop
can be a blackhole which affects the fib6_type and flags (REJECT).

v2
- fixed 2 bugs in patch12:
  i. checking return from fib6_table_lookup in fib6_lookup
  ii. call to fib6_rule_saddr in fib6_rule_action_alt should use res->nh
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_fib.h

@@ -190,6 +190,13 @@ struct rt6_info {
 	unsigned short			rt6i_nfheader_len;
 };
 
+struct fib6_result {
+	struct fib6_nh		*nh;
+	struct fib6_info	*f6i;
+	u32			fib6_flags;
+	u8			fib6_type;
+};
+
 #define for_each_fib6_node_rt_rcu(fn)					\
 	for (rt = rcu_dereference((fn)->leaf); rt;			\
 	     rt = rcu_dereference(rt->fib6_next))
@@ -384,18 +391,17 @@ 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);
 
-struct fib6_info *fib6_multipath_select(const struct net *net,
-					struct fib6_info *match,
-					struct flowi6 *fl6, int oif,
+void fib6_select_path(const struct net *net, struct fib6_result *res,
+		      struct flowi6 *fl6, int oif, bool have_oif_match,
 		      const struct sk_buff *skb, int strict);
-
 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
 				   const struct in6_addr *daddr,
 				   const struct in6_addr *saddr);

include/net/ip6_route.h

@@ -302,8 +302,9 @@ static inline unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
 	return mtu;
 }
 
-u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
-		      struct in6_addr *saddr);
+u32 ip6_mtu_from_fib6(const struct fib6_result *res,
+		      const struct in6_addr *daddr,
+		      const struct in6_addr *saddr);
 
 struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
 				   struct net_device *dev, struct sk_buff *skb,

include/net/ipv6_stubs.h

@@ -14,6 +14,7 @@
 struct fib6_info;
 struct fib6_nh;
 struct fib6_config;
+struct fib6_result;
 
 /* This is ugly, ideally these symbols should be built
  * into the core kernel.
@@ -28,19 +29,17 @@ 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_info *(*fib6_multipath_select)(const struct net *net,
-						   struct fib6_info *f6i,
-						   struct flowi6 *fl6, int oif,
-						   const struct sk_buff *skb,
-						   int strict);
-	u32 (*ip6_mtu_from_fib6)(struct fib6_info *f6i, struct in6_addr *daddr,
-				 struct in6_addr *saddr);
+				 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);
+	u32 (*ip6_mtu_from_fib6)(const struct fib6_result *res,
+				 const struct in6_addr *daddr,
+				 const struct in6_addr *saddr);
 
 	int (*fib6_nh_init)(struct net *net, struct fib6_nh *fib6_nh,
 			    struct fib6_config *cfg, gfp_t gfp_flags,

include/trace/events/fib6.h

@@ -12,10 +12,10 @@
 
 TRACE_EVENT(fib6_table_lookup,
 
-	TP_PROTO(const struct net *net, const struct fib6_info *f6i,
+	TP_PROTO(const struct net *net, const struct fib6_result *res,
 		 struct fib6_table *table, const struct flowi6 *flp),
 
-	TP_ARGS(net, f6i, table, flp),
+	TP_ARGS(net, res, table, flp),
 
 	TP_STRUCT__entry(
 		__field(	u32,	tb_id		)
@@ -39,7 +39,7 @@ TRACE_EVENT(fib6_table_lookup,
 		struct in6_addr *in6;
 
 		__entry->tb_id = table->tb6_id;
-		__entry->err = ip6_rt_type_to_error(f6i->fib6_type);
+		__entry->err = ip6_rt_type_to_error(res->fib6_type);
 		__entry->oif = flp->flowi6_oif;
 		__entry->iif = flp->flowi6_iif;
 		__entry->tos = ip6_tclass(flp->flowlabel);
@@ -62,20 +62,20 @@ TRACE_EVENT(fib6_table_lookup,
 			__entry->dport = 0;
 		}
 
-		if (f6i->fib6_nh.fib_nh_dev) {
-			__assign_str(name, f6i->fib6_nh.fib_nh_dev);
+		if (res->nh && res->nh->fib_nh_dev) {
+			__assign_str(name, res->nh->fib_nh_dev);
 		} else {
 			__assign_str(name, "-");
 		}
-		if (f6i == net->ipv6.fib6_null_entry) {
+		if (res->f6i == net->ipv6.fib6_null_entry) {
 			struct in6_addr in6_zero = {};
 
 			in6 = (struct in6_addr *)__entry->gw;
 			*in6 = in6_zero;
 
-		} else if (f6i) {
+		} else if (res->nh) {
 			in6 = (struct in6_addr *)__entry->gw;
-			*in6 = f6i->fib6_nh.fib_nh_gw6;
+			*in6 = res->nh->fib_nh_gw6;
 		}
 	),
 

net/core/filter.c

@@ -4679,12 +4679,12 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 	struct in6_addr *src = (struct in6_addr *) params->ipv6_src;
 	struct in6_addr *dst = (struct in6_addr *) params->ipv6_dst;
 	struct neighbour *neigh;
+	struct fib6_result res;
 	struct net_device *dev;
 	struct inet6_dev *idev;
-	struct fib6_info *f6i;
 	struct flowi6 fl6;
 	int strict = 0;
-	int oif;
+	int oif, err;
 	u32 mtu;
 
 	/* link local addresses are never forwarded */
@@ -4726,21 +4726,25 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 		if (unlikely(!tb))
 			return BPF_FIB_LKUP_RET_NOT_FWDED;
 
-		f6i = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6, strict);
+		err = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6, &res,
+						   strict);
 	} else {
 		fl6.flowi6_mark = 0;
 		fl6.flowi6_secid = 0;
 		fl6.flowi6_tun_key.tun_id = 0;
 		fl6.flowi6_uid = sock_net_uid(net, NULL);
 
-		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(f6i) || f6i == net->ipv6.fib6_null_entry))
+	if (unlikely(err || IS_ERR_OR_NULL(res.f6i) ||
+		     res.f6i == net->ipv6.fib6_null_entry))
 		return BPF_FIB_LKUP_RET_NOT_FWDED;
 
-	if (unlikely(f6i->fib6_flags & RTF_REJECT)) {
-		switch (f6i->fib6_type) {
+	switch (res.fib6_type) {
+	/* only unicast is forwarded */
+	case RTN_UNICAST:
+		break;
 	case RTN_BLACKHOLE:
 		return BPF_FIB_LKUP_RET_BLACKHOLE;
 	case RTN_UNREACHABLE:
@@ -4750,30 +4754,24 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 	default:
 		return BPF_FIB_LKUP_RET_NOT_FWDED;
 	}
-	}
 
-	if (f6i->fib6_type != RTN_UNICAST)
-		return BPF_FIB_LKUP_RET_NOT_FWDED;
-
-	if (f6i->fib6_nsiblings && fl6.flowi6_oif == 0)
-		f6i = ipv6_stub->fib6_multipath_select(net, f6i, &fl6,
-						       fl6.flowi6_oif, NULL,
-						       strict);
+	ipv6_stub->fib6_select_path(net, &res, &fl6, fl6.flowi6_oif,
+				    fl6.flowi6_oif != 0, NULL, strict);
 
 	if (check_mtu) {
-		mtu = ipv6_stub->ip6_mtu_from_fib6(f6i, dst, src);
+		mtu = ipv6_stub->ip6_mtu_from_fib6(&res, dst, src);
 		if (params->tot_len > mtu)
 			return BPF_FIB_LKUP_RET_FRAG_NEEDED;
 	}
 
-	if (f6i->fib6_nh.fib_nh_lws)
+	if (res.nh->fib_nh_lws)
 		return BPF_FIB_LKUP_RET_UNSUPP_LWT;
 
-	if (f6i->fib6_nh.fib_nh_gw_family)
-		*dst = f6i->fib6_nh.fib_nh_gw6;
+	if (res.nh->fib_nh_gw_family)
+		*dst = res.nh->fib_nh_gw6;
 
-	dev = f6i->fib6_nh.fib_nh_dev;
-	params->rt_metric = f6i->fib6_metric;
+	dev = res.nh->fib_nh_dev;
+	params->rt_metric = res.f6i->fib6_metric;
 
 	/* xdp and cls_bpf programs are run in RCU-bh so rcu_read_lock_bh is
 	 * not needed here.

net/ipv6/addrconf_core.c

@@ -144,31 +144,32 @@ 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 struct fib6_info *
-eafnosupport_fib6_multipath_select(const struct net *net, struct fib6_info *f6i,
-				   struct flowi6 *fl6, int oif,
+static void
+eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
+			      struct flowi6 *fl6, int oif, bool have_oif_match,
 			      const struct sk_buff *skb, int strict)
 {
-	return f6i;
 }
 
 static u32
-eafnosupport_ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
-			       struct in6_addr *saddr)
+eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
+			       const struct in6_addr *daddr,
+			       const struct in6_addr *saddr)
 {
 	return 0;
 }
@@ -187,7 +188,7 @@ const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
 	.fib6_get_table    = eafnosupport_fib6_get_table,
 	.fib6_table_lookup = eafnosupport_fib6_table_lookup,
 	.fib6_lookup       = eafnosupport_fib6_lookup,
-	.fib6_multipath_select = eafnosupport_fib6_multipath_select,
+	.fib6_select_path  = eafnosupport_fib6_select_path,
 	.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
 	.fib6_nh_init	   = eafnosupport_fib6_nh_init,
 };

net/ipv6/af_inet6.c

@@ -917,7 +917,7 @@ static const struct ipv6_stub ipv6_stub_impl = {
 	.fib6_get_table	   = fib6_get_table,
 	.fib6_table_lookup = fib6_table_lookup,
 	.fib6_lookup       = fib6_lookup,
-	.fib6_multipath_select = fib6_multipath_select,
+	.fib6_select_path  = fib6_select_path,
 	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
 	.fib6_nh_init	   = fib6_nh_init,
 	.fib6_nh_release   = fib6_nh_release,

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)