[IPSEC]: Store idev entries

I found a bug that stopped IPsec/IPv6 from working.  About
a month ago IPv6 started using rt6i_idev->dev on the cached socket dst
entries.  If the cached socket dst entry is IPsec, then rt6i_idev will
be NULL.

Since we want to look at the rt6i_idev of the original route in this
case, the easiest fix is to store rt6i_idev in the IPsec dst entry just
as we do for a number of other IPv6 route attributes.  Unfortunately
this means that we need some new code to handle the references to
rt6i_idev.  That's why this patch is bigger than it would otherwise be.

I've also done the same thing for IPv4 since it is conceivable that
once these idev attributes start getting used for accounting, we
probably need to dereference them for IPv4 IPsec entries too.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 0 deletions

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 7fe2afd2e669..b2b60f3e9cdd 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -8,7 +8,10 @@
  *      
  */
 
+#include <asm/bug.h>
+#include <linux/compiler.h>
 #include <linux/config.h>
+#include <linux/inetdevice.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
 
@@ -152,6 +155,8 @@ __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
                 x->u.rt.rt_dst = rt0->rt_dst;
                 x->u.rt.rt_gateway = rt->rt_gateway;
                 x->u.rt.rt_spec_dst = rt0->rt_spec_dst;
+                x->u.rt.idev = rt0->idev;
+                in_dev_hold(rt0->idev);
                 header_len -= x->u.dst.xfrm->props.header_len;
                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
         }
@@ -243,11 +248,48 @@ static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu)
         path->ops->update_pmtu(path, mtu);
 }
 
+static void xfrm4_dst_destroy(struct dst_entry *dst)
+{
+        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+
+        if (likely(xdst->u.rt.idev))
+                in_dev_put(xdst->u.rt.idev);
+        xfrm_dst_destroy(xdst);
+}
+
+static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
+                             int unregister)
+{
+        struct xfrm_dst *xdst;
+
+        if (!unregister)
+                return;
+
+        xdst = (struct xfrm_dst *)dst;
+        if (xdst->u.rt.idev->dev == dev) {
+                struct in_device *loopback_idev = in_dev_get(&loopback_dev);
+                BUG_ON(!loopback_idev);
+
+                do {
+                        in_dev_put(xdst->u.rt.idev);
+                        xdst->u.rt.idev = loopback_idev;
+                        in_dev_hold(loopback_idev);
+                        xdst = (struct xfrm_dst *)xdst->u.dst.child;
+                } while (xdst->u.dst.xfrm);
+
+                __in_dev_put(loopback_idev);
+        }
+
+        xfrm_dst_ifdown(dst, dev);
+}
+
 static struct dst_ops xfrm4_dst_ops = {
         .family =               AF_INET,
         .protocol =             __constant_htons(ETH_P_IP),
         .gc =                   xfrm4_garbage_collect,
         .update_pmtu =          xfrm4_update_pmtu,
+        .destroy =              xfrm4_dst_destroy,
+        .ifdown =               xfrm4_dst_ifdown,
         .gc_thresh =            1024,
         .entry_size =           sizeof(struct xfrm_dst),
 };