netfilter: accounting rework: ct_extend + 64bit counters (v4)

Initially netfilter has had 64bit counters for conntrack-based accounting, but
it was changed in 2.6.14 to save memory. Unfortunately in-kernel 64bit counters are
still required, for example for "connbytes" extension. However, 64bit counters
waste a lot of memory and it was not possible to enable/disable it runtime.

This patch:
 - reimplements accounting with respect to the extension infrastructure,
 - makes one global version of seq_print_acct() instead of two seq_print_counters(),
 - makes it possible to enable it at boot time (for CONFIG_SYSCTL/CONFIG_SYSFS=n),
 - makes it possible to enable/disable it at runtime by sysctl or sysfs,
 - extends counters from 32bit to 64bit,
 - renames ip_conntrack_counter -> nf_conn_counter,
 - enables accounting code unconditionally (no longer depends on CONFIG_NF_CT_ACCT),
 - set initial accounting enable state based on CONFIG_NF_CT_ACCT
 - removes buggy IPCT_COUNTER_FILLING event handling.

If accounting is enabled newly created connections get additional acct extend.
Old connections are not changed as it is not possible to add a ct_extend area
to confirmed conntrack. Accounting is performed for all connections with
acct extend regardless of a current state of "net.netfilter.nf_conntrack_acct".

Signed-off-by: Krzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 17 insertions, 0 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 86334b6f8238..9f73587219e8 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -336,3 +336,13 @@ When:	After the only user (hal) has seen a release with the patches
 Why:    Over 1K .text/.data size reduction, data is available in other
         ways (ioctls)
 Who:    Johannes Berg <johannes@sipsolutions.net>
+
+---------------------------
+
+What: CONFIG_NF_CT_ACCT
+When: 2.6.29
+Why:  Accounting can now be enabled/disabled without kernel recompilation.
+      Currently used only to set a default value for a feature that is also
+      controlled by a kernel/module/sysfs/sysctl parameter.
+Who:  Krzysztof Piotr Oledzki <ole@ans.pl>
+
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 09ad7450647b..e4ef27584408 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1279,6 +1279,13 @@ and is between 256 and 4096 characters. It is defined in the file
                         This usage is only documented in each driver source
                         file if at all.
 
+        nf_conntrack.acct=
+                        [NETFILTER] Enable connection tracking flow accounting
+                        0 to disable accounting
+                        1 to enable accounting
+                        Default value depends on CONFIG_NF_CT_ACCT that is
+                        going to be removed in 2.6.29.
+
         nfsaddrs=       [NFS]
                         See Documentation/filesystems/nfsroot.txt.