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| author | Florian Westphal <fw@strlen.de> | 2017-04-14 20:31:08 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-04-15 11:47:57 +0200 |
| commit | cc41c84b7e7f2d7f6698bccc84890943fd021265 (patch) | |
| tree | 08c09a05f63c6d146e0baf3f8f5f4752092c7622 /include/uapi | |
| parent | 6e354a5e565110c3a0eb7da3788340d4809a42b6 (diff) | |
| download | linux-cc41c84b7e7f2d7f6698bccc84890943fd021265.tar.bz2 | |
netfilter: kill the fake untracked conntrack objects
resurrect an old patch from Pablo Neira to remove the untracked objects.
Currently, there are four possible states of an skb wrt. conntrack.
1. No conntrack attached, ct is NULL.
2. Normal (kmem cache allocated) ct attached.
3. a template (kmalloc'd), not in any hash tables at any point in time
4. the 'untracked' conntrack, a percpu nf_conn object, tagged via
IPS_UNTRACKED_BIT in ct->status.
Untracked is supposed to be identical to case 1. It exists only
so users can check
-m conntrack --ctstate UNTRACKED vs.
-m conntrack --ctstate INVALID
e.g. attempts to set connmark on INVALID or UNTRACKED conntracks is
supposed to be a no-op.
Thus currently we need to check
ct == NULL || nf_ct_is_untracked(ct)
in a lot of places in order to avoid altering untracked objects.
The other consequence of the percpu untracked object is that all
-j NOTRACK (and, later, kfree_skb of such skbs) result in an atomic op
(inc/dec the untracked conntracks refcount).
This adds a new kernel-private ctinfo state, IP_CT_UNTRACKED, to
make the distinction instead.
The (few) places that care about packet invalid (ct is NULL) vs.
packet untracked now need to test ct == NULL vs. ctinfo == IP_CT_UNTRACKED,
but all other places can omit the nf_ct_is_untracked() check.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/netfilter/nf_conntrack_common.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/uapi/linux/netfilter/nf_conntrack_common.h b/include/uapi/linux/netfilter/nf_conntrack_common.h index 6a8e33dd4ecb..b4a0a1940118 100644 --- a/include/uapi/linux/netfilter/nf_conntrack_common.h +++ b/include/uapi/linux/netfilter/nf_conntrack_common.h @@ -28,12 +28,14 @@ enum ip_conntrack_info { /* only for userspace compatibility */ #ifndef __KERNEL__ IP_CT_NEW_REPLY = IP_CT_NUMBER, +#else + IP_CT_UNTRACKED = 7, #endif }; #define NF_CT_STATE_INVALID_BIT (1 << 0) #define NF_CT_STATE_BIT(ctinfo) (1 << ((ctinfo) % IP_CT_IS_REPLY + 1)) -#define NF_CT_STATE_UNTRACKED_BIT (1 << (IP_CT_NUMBER + 1)) +#define NF_CT_STATE_UNTRACKED_BIT (1 << (IP_CT_UNTRACKED + 1)) /* Bitset representing status of connection. */ enum ip_conntrack_status { @@ -94,7 +96,7 @@ enum ip_conntrack_status { IPS_TEMPLATE_BIT = 11, IPS_TEMPLATE = (1 << IPS_TEMPLATE_BIT), - /* Conntrack is a fake untracked entry */ + /* Conntrack is a fake untracked entry. Obsolete and not used anymore */ IPS_UNTRACKED_BIT = 12, IPS_UNTRACKED = (1 << IPS_UNTRACKED_BIT), |