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authorDavid S. Miller <davem@sunset.davemloft.net>2007-05-24 18:17:54 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-05-24 18:17:54 -0700
commit14e50e57aedb2a89cf79b77782879769794cab7b (patch)
tree46cbdab9c8007cea0821294c9d397214b38ea4c8 /net/xfrm
parent04efb8787e4d8a7b21a61aeb723de33154311256 (diff)
downloadlinux-14e50e57aedb2a89cf79b77782879769794cab7b.tar.bz2
[XFRM]: Allow packet drops during larval state resolution.
The current IPSEC rule resolution behavior we have does not work for a lot of people, even though technically it's an improvement from the -EAGAIN buisness we had before. Right now we'll block until the key manager resolves the route. That works for simple cases, but many folks would rather packets get silently dropped until the key manager resolves the IPSEC rules. We can't tell these folks to "set the socket non-blocking" because they don't have control over the non-block setting of things like the sockets used to resolve DNS deep inside of the resolver libraries in libc. With that in mind I coded up the patch below with some help from Herbert Xu which provides packet-drop behavior during larval state resolution, controllable via sysctl and off by default. This lays the framework to either: 1) Make this default at some point or... 2) Move this logic into xfrm{4,6}_policy.c and implement the ARP-like resolution queue we've all been dreaming of. The idea would be to queue packets to the policy, then once the larval state is resolved by the key manager we re-resolve the route and push the packets out. The packets would timeout if the rule didn't get resolved in a certain amount of time. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_policy.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index d0882e53b6fc..b8bab89616a0 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -29,6 +29,8 @@
#include "xfrm_hash.h"
+int sysctl_xfrm_larval_drop;
+
DEFINE_MUTEX(xfrm_cfg_mutex);
EXPORT_SYMBOL(xfrm_cfg_mutex);
@@ -1390,8 +1392,8 @@ static int stale_bundle(struct dst_entry *dst);
* At the moment we eat a raw IP route. Mostly to speed up lookups
* on interfaces with disabled IPsec.
*/
-int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
- struct sock *sk, int flags)
+int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
+ struct sock *sk, int flags)
{
struct xfrm_policy *policy;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
@@ -1509,6 +1511,13 @@ restart:
if (unlikely(nx<0)) {
err = nx;
+ if (err == -EAGAIN && sysctl_xfrm_larval_drop) {
+ /* EREMOTE tells the caller to generate
+ * a one-shot blackhole route.
+ */
+ xfrm_pol_put(policy);
+ return -EREMOTE;
+ }
if (err == -EAGAIN && flags) {
DECLARE_WAITQUEUE(wait, current);
@@ -1598,6 +1607,21 @@ error:
*dst_p = NULL;
return err;
}
+EXPORT_SYMBOL(__xfrm_lookup);
+
+int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
+ struct sock *sk, int flags)
+{
+ int err = __xfrm_lookup(dst_p, fl, sk, flags);
+
+ if (err == -EREMOTE) {
+ dst_release(*dst_p);
+ *dst_p = NULL;
+ err = -EAGAIN;
+ }
+
+ return err;
+}
EXPORT_SYMBOL(xfrm_lookup);
static inline int