[IPSEC]: Merge common code into xfrm_bundle_create

Half of the code in xfrm4_bundle_create and xfrm6_bundle_create are
common.  This patch extracts that logic and puts it into
xfrm_bundle_create.  The rest of it are then accessed through afinfo.

As a result this fixes the problem with inter-family transforms where
we treat every xfrm dst in the bundle as if it belongs to the top
family.

This patch also fixes a long-standing error-path bug where we may free
the xfrm states twice.

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

1 files changed, 159 insertions, 24 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 085c19d4d1b7..b153f7482052 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -24,6 +24,7 @@
 #include <linux/netfilter.h>
 #include <linux/module.h>
 #include <linux/cache.h>
+#include <net/dst.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
 
@@ -50,6 +51,7 @@ static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
 
 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
+static void xfrm_init_pmtu(struct dst_entry *dst);
 
 static inline int
 __xfrm4_selector_match(struct xfrm_selector *sel, struct flowi *fl)
@@ -85,7 +87,8 @@ int xfrm_selector_match(struct xfrm_selector *sel, struct flowi *fl,
         return 0;
 }
 
-struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x, int tos)
+static inline struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x, int tos,
+                                                int family)
 {
         xfrm_address_t *saddr = &x->props.saddr;
         xfrm_address_t *daddr = &x->id.daddr;
@@ -97,7 +100,7 @@ struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x, int tos)
         if (x->type->flags & XFRM_TYPE_REMOTE_COADDR)
                 daddr = x->coaddr;
 
-        afinfo = xfrm_policy_get_afinfo(x->props.family);
+        afinfo = xfrm_policy_get_afinfo(family);
         if (unlikely(afinfo == NULL))
                 return ERR_PTR(-EAFNOSUPPORT);
 
@@ -105,7 +108,6 @@ struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x, int tos)
         xfrm_policy_put_afinfo(afinfo);
         return dst;
 }
-EXPORT_SYMBOL(xfrm_dst_lookup);
 
 static inline unsigned long make_jiffies(long secs)
 {
@@ -1234,24 +1236,164 @@ xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short fa
         return x;
 }
 
-/* Allocate chain of dst_entry's, attach known xfrm's, calculate
- * all the metrics... Shortly, bundle a bundle.
- */
+static inline int xfrm_get_tos(struct flowi *fl, int family)
+{
+        struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+        int tos;
 
-static int
-xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
-                   struct flowi *fl, struct dst_entry **dst_p,
-                   unsigned short family)
+        if (!afinfo)
+                return -EINVAL;
+
+        tos = afinfo->get_tos(fl);
+
+        xfrm_policy_put_afinfo(afinfo);
+
+        return tos;
+}
+
+static inline struct xfrm_dst *xfrm_alloc_dst(int family)
 {
-        int err;
         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
-        if (unlikely(afinfo == NULL))
+        struct xfrm_dst *xdst;
+
+        if (!afinfo)
+                return ERR_PTR(-EINVAL);
+
+        xdst = dst_alloc(afinfo->dst_ops) ?: ERR_PTR(-ENOBUFS);
+
+        xfrm_policy_put_afinfo(afinfo);
+
+        return xdst;
+}
+
+static inline int xfrm_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
+{
+        struct xfrm_policy_afinfo *afinfo =
+                xfrm_policy_get_afinfo(xdst->u.dst.ops->family);
+        int err;
+
+        if (!afinfo)
                 return -EINVAL;
-        err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
+
+        err = afinfo->fill_dst(xdst, dev);
+
         xfrm_policy_put_afinfo(afinfo);
+
         return err;
 }
 
+/* Allocate chain of dst_entry's, attach known xfrm's, calculate
+ * all the metrics... Shortly, bundle a bundle.
+ */
+
+static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
+                                            struct xfrm_state **xfrm, int nx,
+                                            struct flowi *fl,
+                                            struct dst_entry *dst)
+{
+        unsigned long now = jiffies;
+        struct net_device *dev;
+        struct dst_entry *dst_prev = NULL;
+        struct dst_entry *dst0 = NULL;
+        int i = 0;
+        int err;
+        int header_len = 0;
+        int trailer_len = 0;
+        int tos;
+        int family = policy->selector.family;
+
+        tos = xfrm_get_tos(fl, family);
+        err = tos;
+        if (tos < 0)
+                goto put_states;
+
+        dst_hold(dst);
+
+        for (; i < nx; i++) {
+                struct xfrm_dst *xdst = xfrm_alloc_dst(family);
+                struct dst_entry *dst1 = &xdst->u.dst;
+
+                err = PTR_ERR(xdst);
+                if (IS_ERR(xdst)) {
+                        dst_release(dst);
+                        goto put_states;
+                }
+
+                if (!dst_prev)
+                        dst0 = dst1;
+                else {
+                        dst_prev->child = dst_clone(dst1);
+                        dst1->flags |= DST_NOHASH;
+                }
+
+                xdst->route = dst;
+                memcpy(&dst1->metrics, &dst->metrics, sizeof(dst->metrics));
+
+                if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
+                        family = xfrm[i]->props.family;
+                        dst = xfrm_dst_lookup(xfrm[i], tos, family);
+                        err = PTR_ERR(dst);
+                        if (IS_ERR(dst))
+                                goto put_states;
+                } else
+                        dst_hold(dst);
+
+                dst1->xfrm = xfrm[i];
+                xdst->genid = xfrm[i]->genid;
+
+                dst1->obsolete = -1;
+                dst1->flags |= DST_HOST;
+                dst1->lastuse = now;
+
+                dst1->input = dst_discard;
+                dst1->output = xfrm[i]->outer_mode->afinfo->output;
+
+                dst1->next = dst_prev;
+                dst_prev = dst1;
+
+                header_len += xfrm[i]->props.header_len;
+                trailer_len += xfrm[i]->props.trailer_len;
+        }
+
+        dst_prev->child = dst;
+        dst0->path = dst;
+
+        err = -ENODEV;
+        dev = dst->dev;
+        if (!dev)
+                goto free_dst;
+
+        /* Copy neighbout for reachability confirmation */
+        dst0->neighbour = neigh_clone(dst->neighbour);
+
+        xfrm_init_pmtu(dst_prev);
+
+        for (dst_prev = dst0; dst_prev != dst; dst_prev = dst_prev->child) {
+                struct xfrm_dst *xdst = (struct xfrm_dst *)dst_prev;
+
+                err = xfrm_fill_dst(xdst, dev);
+                if (err)
+                        goto free_dst;
+
+                dst_prev->header_len = header_len;
+                dst_prev->trailer_len = trailer_len;
+                header_len -= xdst->u.dst.xfrm->props.header_len;
+                trailer_len -= xdst->u.dst.xfrm->props.trailer_len;
+        }
+
+out:
+        return dst0;
+
+put_states:
+        for (; i < nx; i++)
+                xfrm_state_put(xfrm[i]);
+free_dst:
+        if (dst0)
+                dst_free(dst0);
+        dst0 = ERR_PTR(err);
+        goto out;
+}
+
 static int inline
 xfrm_dst_alloc_copy(void **target, void *src, int size)
 {
@@ -1454,15 +1596,10 @@ restart:
                         return 0;
                 }
 
-                dst = dst_orig;
-                err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
-
-                if (unlikely(err)) {
-                        int i;
-                        for (i=0; i<nx; i++)
-                                xfrm_state_put(xfrm[i]);
+                dst = xfrm_bundle_create(policy, xfrm, nx, fl, dst_orig);
+                err = PTR_ERR(dst);
+                if (IS_ERR(dst))
                         goto error;
-                }
 
                 for (pi = 0; pi < npols; pi++) {
                         read_lock_bh(&pols[pi]->lock);
@@ -1886,7 +2023,7 @@ static int xfrm_flush_bundles(void)
         return 0;
 }
 
-void xfrm_init_pmtu(struct dst_entry *dst)
+static void xfrm_init_pmtu(struct dst_entry *dst)
 {
         do {
                 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
@@ -1907,8 +2044,6 @@ void xfrm_init_pmtu(struct dst_entry *dst)
         } while ((dst = dst->next));
 }
 
-EXPORT_SYMBOL(xfrm_init_pmtu);
-
 /* Check that the bundle accepts the flow and its components are
  * still valid.
  */