[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/include/linux/netfilter.h b/include/linux/netfilter.h
index be365e7..79bb977 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -168,6 +168,37 @@
const struct net_device *out,
struct nf_loginfo *li,
const char *fmt, ...);
+
+int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
+ struct net_device *indev, struct net_device *outdev,
+ int (*okfn)(struct sk_buff *), int thresh);
+
+/**
+ * nf_hook_thresh - call a netfilter hook
+ *
+ * Returns 1 if the hook has allowed the packet to pass. The function
+ * okfn must be invoked by the caller in this case. Any other return
+ * value indicates the packet has been consumed by the hook.
+ */
+static inline int nf_hook_thresh(int pf, unsigned int hook,
+ struct sk_buff **pskb,
+ struct net_device *indev,
+ struct net_device *outdev,
+ int (*okfn)(struct sk_buff *), int thresh)
+{
+#ifndef CONFIG_NETFILTER_DEBUG
+ if (list_empty(&nf_hooks[pf][hook]))
+ return 1;
+#endif
+ return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
+}
+
+static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
+ struct net_device *indev, struct net_device *outdev,
+ int (*okfn)(struct sk_buff *))
+{
+ return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN);
+}
/* Activate hook; either okfn or kfree_skb called, unless a hook
returns NF_STOLEN (in which case, it's up to the hook to deal with
@@ -188,35 +219,17 @@
/* This is gross, but inline doesn't cut it for avoiding the function
call in fast path: gcc doesn't inline (needs value tracking?). --RR */
-#ifdef CONFIG_NETFILTER_DEBUG
-#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
-({int __ret; \
-if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \
- __ret = (okfn)(skb); \
-__ret;})
-#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
-({int __ret; \
-if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \
- __ret = (okfn)(skb); \
-__ret;})
-#else
-#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
-({int __ret; \
-if (list_empty(&nf_hooks[pf][hook]) || \
- (__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \
- __ret = (okfn)(skb); \
-__ret;})
-#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
-({int __ret; \
-if (list_empty(&nf_hooks[pf][hook]) || \
- (__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \
- __ret = (okfn)(skb); \
-__ret;})
-#endif
-int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
- struct net_device *indev, struct net_device *outdev,
- int (*okfn)(struct sk_buff *), int thresh);
+/* HX: It's slightly less gross now. */
+
+#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
+({int __ret; \
+if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1)\
+ __ret = (okfn)(skb); \
+__ret;})
+
+#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
+ NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
/* Call setsockopt() */
int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
diff --git a/include/net/dst.h b/include/net/dst.h
index bee8b84d..5161e89 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -225,16 +225,7 @@
/* Output packet to network from transport. */
static inline int dst_output(struct sk_buff *skb)
{
- int err;
-
- for (;;) {
- err = skb->dst->output(skb);
-
- if (likely(err == 0))
- return err;
- if (unlikely(err != NET_XMIT_BYPASS))
- return err;
- }
+ return skb->dst->output(skb);
}
/* Input packet from network to transport. */
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);
+}
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 6b98677..fc0ea38 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -9,9 +9,11 @@
* 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/icmpv6.h>
+#include <linux/netfilter_ipv6.h>
#include <net/dsfield.h>
#include <net/inet_ecn.h>
#include <net/ipv6.h>
@@ -92,7 +94,7 @@
return ret;
}
-int xfrm6_output(struct sk_buff *skb)
+static int xfrm6_output_one(struct sk_buff *skb)
{
struct dst_entry *dst = skb->dst;
struct xfrm_state *x = dst->xfrm;
@@ -110,29 +112,34 @@
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;
- xfrm6_encap(skb);
+ xfrm6_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);
- skb->nh.raw = skb->data;
-
- if (!(skb->dst = dst_pop(dst))) {
- err = -EHOSTUNREACH;
- goto error_nolock;
- }
- err = NET_XMIT_BYPASS;
+ skb->nh.raw = skb->data;
+
+ 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;
@@ -142,3 +149,33 @@
kfree_skb(skb);
goto out_exit;
}
+
+static int xfrm6_output_finish(struct sk_buff *skb)
+{
+ int err;
+
+ while (likely((err = xfrm6_output_one(skb)) == 0)) {
+ nf_reset(skb);
+
+ err = nf_hook(PF_INET6, NF_IP6_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_INET6, NF_IP6_POST_ROUTING, &skb, NULL,
+ skb->dst->dev, xfrm6_output_finish);
+ if (unlikely(err != 1))
+ break;
+ }
+
+ return err;
+}
+
+int xfrm6_output(struct sk_buff *skb)
+{
+ return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dst->dev,
+ xfrm6_output_finish);
+}
