xfrm: introduce helper for safe determination of mtu

[~andy/linux] / net / ipv6 / xfrm6_output.c

diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 4eeff89c1aaa7d44d8b6369583b0b9e1c15317e9..3ac5ab264fedd3dcb7988eb47782c1835ea3c234 100644 (file)
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -34,8 +34,10 @@ static int xfrm6_local_dontfrag(struct sk_buff *skb)
        struct sock *sk = skb->sk;
 
        if (sk) {
-               proto = sk->sk_protocol;
+               if (sk->sk_family != AF_INET6)
+                       return 0;
 
+               proto = sk->sk_protocol;
                if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
                        return inet6_sk(sk)->dontfrag;
        }
@@ -54,7 +56,7 @@ static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
        ipv6_local_rxpmtu(sk, &fl6, mtu);
 }
 
-static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
+void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
 {
        struct flowi6 fl6;
        struct sock *sk = skb->sk;
@@ -80,7 +82,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb)
                if (xfrm6_local_dontfrag(skb))
                        xfrm6_local_rxpmtu(skb, mtu);
                else if (skb->sk)
-                       xfrm6_local_error(skb, mtu);
+                       xfrm_local_error(skb, mtu);
                else
                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
                ret = -EMSGSIZE;
@@ -136,17 +138,20 @@ static int __xfrm6_output(struct sk_buff *skb)
 {
        struct dst_entry *dst = skb_dst(skb);
        struct xfrm_state *x = dst->xfrm;
-       int mtu = ip6_skb_dst_mtu(skb);
+       int mtu = xfrm_skb_dst_mtu(skb);
+
+       if (mtu < IPV6_MIN_MTU)
+               mtu = IPV6_MIN_MTU;
 
        if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
                xfrm6_local_rxpmtu(skb, mtu);
                return -EMSGSIZE;
        } else if (!skb->local_df && skb->len > mtu && skb->sk) {
-               xfrm6_local_error(skb, mtu);
+               xfrm_local_error(skb, mtu);
                return -EMSGSIZE;
        }
 
-       if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&
+       if (x->props.mode == XFRM_MODE_TUNNEL &&
            ((skb->len > mtu && !skb_is_gso(skb)) ||
                dst_allfrag(skb_dst(skb)))) {
                        return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);