xfrm: remove afinfo pointer from xfrm_mode

Adds an EXPORT_SYMBOL for afinfo_get_rcu, as it will now be called from
ipv6 in case of CONFIG_IPV6=m.

This change has virtually no effect on vmlinux size, but it reduces
afinfo size and allows followup patch to make xfrm modes const.

v2: mark if (afinfo) tests as likely (Sabrina)
    re-fetch afinfo according to inner_mode in xfrm_prepare_input().

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 2b663d2ffdcd..455fbf3b91cf 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -122,11 +122,28 @@ int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
         return xfrm_output(sk, skb);
 }
 
+static int __xfrm6_output_state_finish(struct xfrm_state *x, struct sock *sk,
+                                       struct sk_buff *skb)
+{
+        const struct xfrm_state_afinfo *afinfo;
+        int ret = -EAFNOSUPPORT;
+
+        rcu_read_lock();
+        afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode->family);
+        if (likely(afinfo))
+                ret = afinfo->output_finish(sk, skb);
+        else
+                kfree_skb(skb);
+        rcu_read_unlock();
+
+        return ret;
+}
+
 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
         struct xfrm_state *x = skb_dst(skb)->xfrm;
 
-        return x->outer_mode->afinfo->output_finish(sk, skb);
+        return __xfrm6_output_state_finish(x, sk, skb);
 }
 
 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
@@ -168,7 +185,7 @@ static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
                                     __xfrm6_output_finish);
 
 skip_frag:
-        return x->outer_mode->afinfo->output_finish(sk, skb);
+        return __xfrm6_output_state_finish(x, sk, skb);
 }
 
 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)