[XFRM]: Netfilter IPsec output hooks
Call netfilter hooks before IPsec transforms. Packets visit the
FORWARD/LOCAL_OUT and POST_ROUTING hook before the first encapsulation
and the LOCAL_OUT and POST_ROUTING hook before each following tunnel mode
transform.
Patch from Herbert Xu <herbert@gondor.apana.org.au>:
Move the loop from dst_output into xfrm4_output/xfrm6_output since they're
the only ones who need to it. xfrm{4,6}_output_one() processes the first SA
all subsequent transport mode SAs and is called in a loop that calls the
netfilter hooks between each two calls.
In order to avoid the tail call issue, I've added the inline function
nf_hook which is nf_hook_slow plus the empty list check.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index 66620a9..51fabb8 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -8,8 +8,10 @@
* 2 of the License, or (at your option) any later version.
*/
+#include <linux/compiler.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
+#include <linux/netfilter_ipv4.h>
#include <net/inet_ecn.h>
#include <net/ip.h>
#include <net/xfrm.h>
@@ -95,7 +97,7 @@
return ret;
}
-int xfrm4_output(struct sk_buff *skb)
+static int xfrm4_output_one(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct xfrm_state *x = dst->xfrm;
@@ -113,27 +115,32 @@
goto error_nolock;
}
- spin_lock_bh(&x->lock);
- err = xfrm_state_check(x, skb);
- if (err)
- goto error;
+ do {
+ spin_lock_bh(&x->lock);
+ err = xfrm_state_check(x, skb);
+ if (err)
+ goto error;
- xfrm4_encap(skb);
+ xfrm4_encap(skb);
- err = x->type->output(x, skb);
- if (err)
- goto error;
+ err = x->type->output(x, skb);
+ if (err)
+ goto error;
- x->curlft.bytes += skb->len;
- x->curlft.packets++;
+ x->curlft.bytes += skb->len;
+ x->curlft.packets++;
- spin_unlock_bh(&x->lock);
+ spin_unlock_bh(&x->lock);
- if (!(skb->dst = dst_pop(dst))) {
- err = -EHOSTUNREACH;
- goto error_nolock;
- }
- err = NET_XMIT_BYPASS;
+ if (!(skb->dst = dst_pop(dst))) {
+ err = -EHOSTUNREACH;
+ goto error_nolock;
+ }
+ dst = skb->dst;
+ x = dst->xfrm;
+ } while (x && !x->props.mode);
+
+ err = 0;
out_exit:
return err;
@@ -143,3 +150,33 @@
kfree_skb(skb);
goto out_exit;
}
+
+static int xfrm4_output_finish(struct sk_buff *skb)
+{
+ int err;
+
+ while (likely((err = xfrm4_output_one(skb)) == 0)) {
+ nf_reset(skb);
+
+ err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL,
+ skb->dst->dev, dst_output);
+ if (unlikely(err != 1))
+ break;
+
+ if (!skb->dst->xfrm)
+ return dst_output(skb);
+
+ err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL,
+ skb->dst->dev, xfrm4_output_finish);
+ if (unlikely(err != 1))
+ break;
+ }
+
+ return err;
+}
+
+int xfrm4_output(struct sk_buff *skb)
+{
+ return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
+ xfrm4_output_finish);
+}