[RFC v2 bpf-next 7/9] net/ipv6: Add fib lookup stubs for use in bpf helper

[David Ahern <dsahern@gmail.com>]

Add stubs to retrieve a handle to an IPv6 FIB table, fib6_get_table,
a stub to do a lookup in a specific table, fib6_table_lookup, and
a stub for a full route lookup.

The stubs are needed for core bpf code to handle the case when the
IPv6 module is not builtin.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 include/net/addrconf.h   | 14 ++++++++++++++
 net/ipv6/addrconf_core.c | 33 ++++++++++++++++++++++++++++++++-
 net/ipv6/af_inet6.c      |  6 +++++-
 3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 8312cc25a3af..ff766ab207e0 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -223,6 +223,20 @@ struct ipv6_stub {
 				 const struct in6_addr *addr);
 	int (*ipv6_dst_lookup)(struct net *net, struct sock *sk,
 			       struct dst_entry **dst, struct flowi6 *fl6);
+
+	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 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);
+
 	void (*udpv6_encap_enable)(void);
 	void (*ndisc_send_na)(struct net_device *dev, const struct in6_addr *daddr,
 			      const struct in6_addr *solicited_addr,
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 32b564dfd02a..2fe754fd4f5e 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -134,8 +134,39 @@ static int eafnosupport_ipv6_dst_lookup(struct net *net, struct sock *u1,
 	return -EAFNOSUPPORT;
 }
 
+static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
+{
+	return NULL;
+}
+
+static struct fib6_info *
+eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
+			       int oif, struct flowi6 *fl6, int flags)
+{
+	return NULL;
+}
+
+static struct fib6_info *
+eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+			 int flags)
+{
+	return NULL;
+}
+
+static struct fib6_info *
+eafnosupport_fib6_multipath_select(const struct net *net, struct fib6_info *f6i,
+				   struct flowi6 *fl6, int oif,
+				   const struct sk_buff *skb, int strict)
+{
+	return f6i;
+}
+
 const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
-	.ipv6_dst_lookup = eafnosupport_ipv6_dst_lookup,
+	.ipv6_dst_lookup   = eafnosupport_ipv6_dst_lookup,
+	.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,
 };
 EXPORT_SYMBOL_GPL(ipv6_stub);
 
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 36d622c477b1..c0e8255d50bb 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -887,7 +887,11 @@ static struct pernet_operations inet6_net_ops = {
 static const struct ipv6_stub ipv6_stub_impl = {
 	.ipv6_sock_mc_join = ipv6_sock_mc_join,
 	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
-	.ipv6_dst_lookup = ip6_dst_lookup,
+	.ipv6_dst_lookup   = ip6_dst_lookup,
+	.fib6_get_table	   = fib6_get_table,
+	.fib6_table_lookup = fib6_table_lookup,
+	.fib6_lookup       = fib6_lookup,
+	.fib6_multipath_select = fib6_multipath_select,
 	.udpv6_encap_enable = udpv6_encap_enable,
 	.ndisc_send_na = ndisc_send_na,
 	.nd_tbl	= &nd_tbl,
-- 
2.11.0