[IPSEC]: IPv6 over IPv4 IPsec tunnel

This is the patch to support IPv6 over IPv4 IPsec

Signed-off-by: Miika Komu <miika@iki.fi>
Signed-off-by: Diego Beltrami <Diego.Beltrami@hiit.fi>
Signed-off-by: Kazunori Miyazawa <miyazawa@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 11 deletions

diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index e23c21d31a53..e54c5494c88f 100644
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -23,6 +23,12 @@ static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
                 IP_ECN_set_ce(inner_iph);
 }
 
+static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
+{
+        if (INET_ECN_is_ce(iph->tos))
+                IP6_ECN_set_ce(skb->nh.ipv6h);
+}
+
 /* Add encapsulation header.
  *
  * The top IP header will be constructed per RFC 2401.  The following fields
@@ -36,6 +42,7 @@ static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
 static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         struct dst_entry *dst = skb->dst;
+        struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
         struct iphdr *iph, *top_iph;
         int flags;
 
@@ -48,15 +55,27 @@ static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
         top_iph->ihl = 5;
         top_iph->version = 4;
 
+        flags = x->props.flags;
+
         /* DS disclosed */
-        top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
+        if (xdst->route->ops->family == AF_INET) {
+                top_iph->protocol = IPPROTO_IPIP;
+                top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
+                top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
+                        0 : (iph->frag_off & htons(IP_DF));
+        }
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+        else {
+                struct ipv6hdr *ipv6h = (struct ipv6hdr*)iph;
+                top_iph->protocol = IPPROTO_IPV6;
+                top_iph->tos = INET_ECN_encapsulate(iph->tos, ipv6_get_dsfield(ipv6h));
+                top_iph->frag_off = 0;
+        }
+#endif
 
-        flags = x->props.flags;
         if (flags & XFRM_STATE_NOECN)
                 IP_ECN_clear(top_iph);
 
-        top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
-                0 : (iph->frag_off & htons(IP_DF));
         if (!top_iph->frag_off)
                 __ip_select_ident(top_iph, dst->child, 0);
 
@@ -64,7 +83,6 @@ static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 
         top_iph->saddr = x->props.saddr.a4;
         top_iph->daddr = x->id.daddr.a4;
-        top_iph->protocol = IPPROTO_IPIP;
 
         memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
         return 0;
@@ -75,8 +93,16 @@ static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
         struct iphdr *iph = skb->nh.iph;
         int err = -EINVAL;
 
-        if (iph->protocol != IPPROTO_IPIP)
-                goto out;
+        switch(iph->protocol){
+                case IPPROTO_IPIP:
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+                case IPPROTO_IPV6:
+                        break;
+#endif
+                default:
+                        goto out;
+        }
+
         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
                 goto out;
 
@@ -84,10 +110,19 @@ static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
             (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
                 goto out;
 
-        if (x->props.flags & XFRM_STATE_DECAP_DSCP)
-                ipv4_copy_dscp(iph, skb->h.ipiph);
-        if (!(x->props.flags & XFRM_STATE_NOECN))
-                ipip_ecn_decapsulate(skb);
+        if (iph->protocol == IPPROTO_IPIP) {
+                if (x->props.flags & XFRM_STATE_DECAP_DSCP)
+                        ipv4_copy_dscp(iph, skb->h.ipiph);
+                if (!(x->props.flags & XFRM_STATE_NOECN))
+                        ipip_ecn_decapsulate(skb);
+        }
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+        else {
+                if (!(x->props.flags & XFRM_STATE_NOECN))
+                        ipip6_ecn_decapsulate(iph, skb);
+                skb->protocol = htons(ETH_P_IPV6);
+        }
+#endif
         skb->mac.raw = memmove(skb->data - skb->mac_len,
                                skb->mac.raw, skb->mac_len);
         skb->nh.raw = skb->data;