ipsec: Interfamily IPSec BEET

Here's a revised version, based on Herbert's comments, of a fix for
the ipv6-inner, ipv4-outer interfamily ipsec beet mode. It fixes the
network header adjustment in interfamily, and doesn't reserve space
for the pseudo header anymore when we have ipv6 as the inner family.
Signed-off-by: Joakim Koskela <jookos@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/esp4.c

@@ -575,7 +575,7 @@ static int esp_init_state(struct xfrm_state *x)
 			      crypto_aead_ivsize(aead);
 	if (x->props.mode == XFRM_MODE_TUNNEL)
 		x->props.header_len += sizeof(struct iphdr);
-	else if (x->props.mode == XFRM_MODE_BEET)
+	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
 		x->props.header_len += IPV4_BEET_PHMAXLEN;
 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;

net/ipv4/xfrm4_mode_beet.c

@@ -47,8 +47,10 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 	if (unlikely(optlen))
 		hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
 
-	skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
-				    hdrlen);
+	skb_set_network_header(skb, -x->props.header_len -
+			            hdrlen + (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
+	if (x->sel.family != AF_INET6)
+		skb->network_header += IPV4_BEET_PHMAXLEN;
 	skb->mac_header = skb->network_header +
 			  offsetof(struct iphdr, protocol);
 	skb->transport_header = skb->network_header + sizeof(*top_iph);