[IPSEC]: IPv6 over IPv4 IPsec tunnel
Miika Komu [Tue, 6 Feb 2007 22:27:02 +0000 (14:27 -0800)]
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>

net/ipv4/xfrm4_mode_tunnel.c
net/ipv6/xfrm6_policy.c

index e23c21d..e54c549 100644 (file)
@@ -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;
index 8dffd4d..59480e9 100644 (file)
@@ -131,13 +131,11 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
        struct dst_entry *dst, *dst_prev;
        struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
        struct rt6_info *rt  = rt0;
-       struct in6_addr *remote = &fl->fl6_dst;
-       struct in6_addr *local  = &fl->fl6_src;
        struct flowi fl_tunnel = {
                .nl_u = {
                        .ip6_u = {
-                               .saddr = *local,
-                               .daddr = *remote
+                               .saddr = fl->fl6_src,
+                               .daddr = fl->fl6_dst,
                        }
                }
        };
@@ -153,7 +151,6 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
        for (i = 0; i < nx; i++) {
                struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
                struct xfrm_dst *xdst;
-               int tunnel = 0;
 
                if (unlikely(dst1 == NULL)) {
                        err = -ENOBUFS;
@@ -177,19 +174,27 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 
                dst1->next = dst_prev;
                dst_prev = dst1;
-               if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
-                       remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
-                       local  = __xfrm6_bundle_addr_local(xfrm[i], local);
-                       tunnel = 1;
-               }
+
                __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
                trailer_len += xfrm[i]->props.trailer_len;
 
-               if (tunnel) {
-                       ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
-                       ipv6_addr_copy(&fl_tunnel.fl6_src, local);
+               if (xfrm[i]->props.mode == XFRM_MODE_TUNNEL) {
+                       unsigned short encap_family = xfrm[i]->props.family;
+                       switch(encap_family) {
+                       case AF_INET:
+                               fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
+                               fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
+                               break;
+                       case AF_INET6:
+                               ipv6_addr_copy(&fl_tunnel.fl6_dst, (struct in6_addr*)&xfrm[i]->id.daddr.a6);
+                               ipv6_addr_copy(&fl_tunnel.fl6_src, (struct in6_addr*)&xfrm[i]->props.saddr.a6);
+                               break;
+                       default:
+                               BUG_ON(1);
+                       }
+
                        err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
-                                             &fl_tunnel, AF_INET6);
+                                             &fl_tunnel, encap_family);
                        if (err)
                                goto error;
                } else
@@ -208,6 +213,7 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
        i = 0;
        for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
                struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
+               struct xfrm_state_afinfo *afinfo;
 
                dst_prev->xfrm = xfrm[i++];
                dst_prev->dev = rt->u.dst.dev;
@@ -224,7 +230,17 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
                /* Copy neighbour for reachability confirmation */
                dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
                dst_prev->input         = rt->u.dst.input;
-               dst_prev->output        = xfrm6_output;
+               /* XXX: When IPv4 is implemented as module and can be unloaded,
+                * we should manage reference to xfrm4_output in afinfo->output.
+                * Miyazawa
+                */
+               afinfo = xfrm_state_get_afinfo(dst_prev->xfrm->props.family);
+               if (!afinfo) {
+                       dst = *dst_p;
+                       goto error;
+               };
+               dst_prev->output = afinfo->output;
+               xfrm_state_put_afinfo(afinfo);
                /* Sheit... I remember I did this right. Apparently,
                 * it was magically lost, so this code needs audit */
                x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);