Subject: [PATCH ipsec-next 4/7] xfrm: expose local_rxpmtu via ipv6_stubs

From: Florian Westphal <[email-masked]>
Date: Tue, 28 Apr 2020 13:40:25 +0200

We cannot call this function from the core kernel unless we would force
CONFIG_IPV6=y.

Therefore expose this via ipv6_stubs so we can call it from net/xfrm
in the followup patch.

Since the call is expected to be unlikely, no extra code for the IPV6=y
case is added and we will always eat the indirection cost.

Signed-off-by: Florian Westphal <[email-masked]>
---
 include/net/ipv6_stubs.h | 3 +++
 include/net/xfrm.h       | 1 +
 net/ipv6/af_inet6.c      | 4 ++++
 net/ipv6/xfrm6_output.c  | 2 +-
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
index 3e7d2c0e79ca..6f363ad01fbf 100644
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h
@@ -56,6 +56,9 @@ struct ipv6_stub {
 	void (*ndisc_send_na)(struct net_device *dev, const struct in6_addr *daddr,
 			      const struct in6_addr *solicited_addr,
 			      bool router, bool solicited, bool override, bool inc_opt);
+#if IS_ENABLED(CONFIG_XFRM)
+	void (*xfrm6_local_rxpmtu)(struct sk_buff *skb, u32 mtu);
+#endif
 	struct neigh_table *nd_tbl;
 };
 extern const struct ipv6_stub *ipv6_stub __read_mostly;
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 5ff10680bc97..4d8be0649464 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1604,6 +1604,7 @@ int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
 			  u8 **prevhdr);
 
 #ifdef CONFIG_XFRM
+void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu);
 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
 int xfrm_user_policy(struct sock *sk, int optname,
 		     u8 __user *optval, int optlen);
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 345baa0a754f..2d8cc02057c8 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -60,6 +60,7 @@
 #include <net/calipso.h>
 #include <net/seg6.h>
 #include <net/rpl.h>
+#include <net/xfrm.h>
 
 #include <linux/uaccess.h>
 #include <linux/mroute6.h>
@@ -961,6 +962,9 @@ static const struct ipv6_stub ipv6_stub_impl = {
 	.ip6_del_rt	   = ip6_del_rt,
 	.udpv6_encap_enable = udpv6_encap_enable,
 	.ndisc_send_na = ndisc_send_na,
+#if IS_ENABLED(CONFIG_XFRM)
+	.xfrm6_local_rxpmtu = xfrm6_local_rxpmtu,
+#endif
 	.nd_tbl	= &nd_tbl,
 };
 
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 855078a43fc7..23e2b52cfba6 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -40,7 +40,7 @@ static int xfrm6_local_dontfrag(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
+void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
 {
 	struct flowi6 fl6;
 	struct sock *sk = skb->sk;
-- 
2.26.2