ipv6: Add fib6_nh_init and release to stubs

Add fib6_nh_init and fib6_nh_release to ipv6_stubs. If fib6_nh_init fails,
callers should not invoke fib6_nh_release, so there is no reason to have
a dummy stub for the IPv6 is not enabled case.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6_stubs.h

@@ -12,6 +12,8 @@
 
 /* structs from net/ip6_fib.h */
 struct fib6_info;
+struct fib6_nh;
+struct fib6_config;
 
 /* This is ugly, ideally these symbols should be built
  * into the core kernel.
@@ -40,6 +42,10 @@ struct ipv6_stub {
 	u32 (*ip6_mtu_from_fib6)(struct fib6_info *f6i, struct in6_addr *daddr,
 				 struct in6_addr *saddr);
 
+	int (*fib6_nh_init)(struct net *net, struct fib6_nh *fib6_nh,
+			    struct fib6_config *cfg, gfp_t gfp_flags,
+			    struct netlink_ext_ack *extack);
+	void (*fib6_nh_release)(struct fib6_nh *fib6_nh);
 	void (*udpv6_encap_enable)(void);
 	void (*ndisc_send_na)(struct net_device *dev, const struct in6_addr *daddr,
 			      const struct in6_addr *solicited_addr,

net/ipv6/addrconf_core.c

@@ -173,6 +173,14 @@ eafnosupport_ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr,
 	return 0;
 }
 
+static int eafnosupport_fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+				     struct fib6_config *cfg, gfp_t gfp_flags,
+				     struct netlink_ext_ack *extack)
+{
+	NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
+	return -EAFNOSUPPORT;
+}
+
 const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
 	.ipv6_dst_lookup   = eafnosupport_ipv6_dst_lookup,
 	.ipv6_route_input  = eafnosupport_ipv6_route_input,
@@ -181,6 +189,7 @@ const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
 	.fib6_lookup       = eafnosupport_fib6_lookup,
 	.fib6_multipath_select = eafnosupport_fib6_multipath_select,
 	.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
+	.fib6_nh_init	   = eafnosupport_fib6_nh_init,
 };
 EXPORT_SYMBOL_GPL(ipv6_stub);
 

net/ipv6/af_inet6.c

@@ -919,6 +919,8 @@ static const struct ipv6_stub ipv6_stub_impl = {
 	.fib6_lookup       = fib6_lookup,
 	.fib6_multipath_select = fib6_multipath_select,
 	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
+	.fib6_nh_init	   = fib6_nh_init,
+	.fib6_nh_release   = fib6_nh_release,
 	.udpv6_encap_enable = udpv6_encap_enable,
 	.ndisc_send_na = ndisc_send_na,
 	.nd_tbl	= &nd_tbl,