netfilter: xtables: generate initial table on-demand

The static initial tables are pretty large, and after the net
namespace has been instantiated, they just hang around for nothing.
This commit removes them and creates tables on-demand at runtime when
needed.

Size shrinks by 7735 bytes (x86_64).

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

8 files changed, 61 insertions, 199 deletions

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 90203e1b9187..72723ea1054b 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -27,6 +27,7 @@
 
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_arp/arp_tables.h>
+#include "../../netfilter/xt_repldata.h"
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
@@ -58,6 +59,12 @@ do {								\
 #define ARP_NF_ASSERT(x)
 #endif
 
+void *arpt_alloc_initial_table(const struct xt_table *info)
+{
+        return xt_alloc_initial_table(arpt, ARPT);
+}
+EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
+
 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
                                       const char *hdr_addr, int len)
 {
diff --git a/net/ipv4/netfilter/arptable_filter.c b/net/ipv4/netfilter/arptable_filter.c
index b361de0dac4c..bfe26f32b930 100644
--- a/net/ipv4/netfilter/arptable_filter.c
+++ b/net/ipv4/netfilter/arptable_filter.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_arp/arp_tables.h>
 
 MODULE_LICENSE("GPL");
@@ -15,36 +16,6 @@ MODULE_DESCRIPTION("arptables filter table");
 #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
                            (1 << NF_ARP_FORWARD))
 
-static const struct
-{
-        struct arpt_replace repl;
-        struct arpt_standard entries[3];
-        struct arpt_error term;
-} initial_table __net_initdata = {
-        .repl = {
-                .name = "filter",
-                .valid_hooks = FILTER_VALID_HOOKS,
-                .num_entries = 4,
-                .size = sizeof(struct arpt_standard) * 3 + sizeof(struct arpt_error),
-                .hook_entry = {
-                        [NF_ARP_IN] = 0,
-                        [NF_ARP_OUT] = sizeof(struct arpt_standard),
-                        [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
-                },
-                .underflow = {
-                        [NF_ARP_IN] = 0,
-                        [NF_ARP_OUT] = sizeof(struct arpt_standard),
-                        [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
-                },
-        },
-        .entries = {
-                ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_IN */
-                ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_OUT */
-                ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_FORWARD */
-        },
-        .term = ARPT_ERROR_INIT,
-};
-
 static const struct xt_table packet_filter = {
         .name           = "filter",
         .valid_hooks    = FILTER_VALID_HOOKS,
@@ -68,9 +39,14 @@ static struct nf_hook_ops *arpfilter_ops __read_mostly;
 
 static int __net_init arptable_filter_net_init(struct net *net)
 {
-        /* Register table */
+        struct arpt_replace *repl;
+        
+        repl = arpt_alloc_initial_table(&packet_filter);
+        if (repl == NULL)
+                return -ENOMEM;
         net->ipv4.arptable_filter =
-                arpt_register_table(net, &packet_filter, &initial_table.repl);
+                arpt_register_table(net, &packet_filter, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.arptable_filter))
                 return PTR_ERR(net->ipv4.arptable_filter);
         return 0;
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 5bf7de1527a5..2057b1bb6178 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -28,6 +28,7 @@
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <net/netfilter/nf_log.h>
+#include "../../netfilter/xt_repldata.h"
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
@@ -66,6 +67,12 @@ do {								\
 #define inline
 #endif
 
+void *ipt_alloc_initial_table(const struct xt_table *info)
+{
+        return xt_alloc_initial_table(ipt, IPT);
+}
+EXPORT_SYMBOL_GPL(ipt_alloc_initial_table);
+
 /*
    We keep a set of rules for each CPU, so we can avoid write-locking
    them in the softirq when updating the counters and therefore
diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c
index c14bb85db1d9..c8dc9800d620 100644
--- a/net/ipv4/netfilter/iptable_filter.c
+++ b/net/ipv4/netfilter/iptable_filter.c
@@ -23,36 +23,6 @@ MODULE_DESCRIPTION("iptables filter table");
                             (1 << NF_INET_FORWARD) | \
                             (1 << NF_INET_LOCAL_OUT))
 
-static struct
-{
-        struct ipt_replace repl;
-        struct ipt_standard entries[3];
-        struct ipt_error term;
-} initial_table __net_initdata = {
-        .repl = {
-                .name = "filter",
-                .valid_hooks = FILTER_VALID_HOOKS,
-                .num_entries = 4,
-                .size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
-                .hook_entry = {
-                        [NF_INET_LOCAL_IN] = 0,
-                        [NF_INET_FORWARD] = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
-                },
-                .underflow = {
-                        [NF_INET_LOCAL_IN] = 0,
-                        [NF_INET_FORWARD] = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
-                },
-        },
-        .entries = {
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_IN */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* FORWARD */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
-        },
-        .term = IPT_ERROR_INIT,                 /* ERROR */
-};
-
 static const struct xt_table packet_filter = {
         .name           = "filter",
         .valid_hooks    = FILTER_VALID_HOOKS,
@@ -86,9 +56,18 @@ module_param(forward, bool, 0000);
 
 static int __net_init iptable_filter_net_init(struct net *net)
 {
-        /* Register table */
+        struct ipt_replace *repl;
+
+        repl = ipt_alloc_initial_table(&packet_filter);
+        if (repl == NULL)
+                return -ENOMEM;
+        /* Entry 1 is the FORWARD hook */
+        ((struct ipt_standard *)repl->entries)[1].target.verdict =
+                -forward - 1;
+
         net->ipv4.iptable_filter =
-                ipt_register_table(net, &packet_filter, &initial_table.repl);
+                ipt_register_table(net, &packet_filter, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.iptable_filter))
                 return PTR_ERR(net->ipv4.iptable_filter);
         return 0;
@@ -113,9 +92,6 @@ static int __init iptable_filter_init(void)
                 return -EINVAL;
         }
 
-        /* Entry 1 is the FORWARD hook */
-        initial_table.entries[1].target.verdict = -forward - 1;
-
         ret = register_pernet_subsys(&iptable_filter_net_ops);
         if (ret < 0)
                 return ret;
diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
index 2355a229f8ee..58d7097baa3d 100644
--- a/net/ipv4/netfilter/iptable_mangle.c
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -27,43 +27,6 @@ MODULE_DESCRIPTION("iptables mangle table");
                             (1 << NF_INET_LOCAL_OUT) | \
                             (1 << NF_INET_POST_ROUTING))
 
-/* Ouch - five different hooks? Maybe this should be a config option..... -- BC */
-static const struct
-{
-        struct ipt_replace repl;
-        struct ipt_standard entries[5];
-        struct ipt_error term;
-} initial_table __net_initdata = {
-        .repl = {
-                .name = "mangle",
-                .valid_hooks = MANGLE_VALID_HOOKS,
-                .num_entries = 6,
-                .size = sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error),
-                .hook_entry = {
-                        [NF_INET_PRE_ROUTING]   = 0,
-                        [NF_INET_LOCAL_IN]      = sizeof(struct ipt_standard),
-                        [NF_INET_FORWARD]       = sizeof(struct ipt_standard) * 2,
-                        [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 3,
-                        [NF_INET_POST_ROUTING]  = sizeof(struct ipt_standard) * 4,
-                },
-                .underflow = {
-                        [NF_INET_PRE_ROUTING]   = 0,
-                        [NF_INET_LOCAL_IN]      = sizeof(struct ipt_standard),
-                        [NF_INET_FORWARD]       = sizeof(struct ipt_standard) * 2,
-                        [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 3,
-                        [NF_INET_POST_ROUTING]  = sizeof(struct ipt_standard) * 4,
-                },
-        },
-        .entries = {
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* PRE_ROUTING */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_IN */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* FORWARD */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* POST_ROUTING */
-        },
-        .term = IPT_ERROR_INIT,                 /* ERROR */
-};
-
 static const struct xt_table packet_mangler = {
         .name           = "mangle",
         .valid_hooks    = MANGLE_VALID_HOOKS,
@@ -134,9 +97,14 @@ static struct nf_hook_ops *mangle_ops __read_mostly;
 
 static int __net_init iptable_mangle_net_init(struct net *net)
 {
-        /* Register table */
+        struct ipt_replace *repl;
+
+        repl = ipt_alloc_initial_table(&packet_mangler);
+        if (repl == NULL)
+                return -ENOMEM;
         net->ipv4.iptable_mangle =
-                ipt_register_table(net, &packet_mangler, &initial_table.repl);
+                ipt_register_table(net, &packet_mangler, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.iptable_mangle))
                 return PTR_ERR(net->ipv4.iptable_mangle);
         return 0;
diff --git a/net/ipv4/netfilter/iptable_raw.c b/net/ipv4/netfilter/iptable_raw.c
index 62a99154f14c..06fb9d11953c 100644
--- a/net/ipv4/netfilter/iptable_raw.c
+++ b/net/ipv4/netfilter/iptable_raw.c
@@ -9,33 +9,6 @@
 
 #define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
 
-static const struct
-{
-        struct ipt_replace repl;
-        struct ipt_standard entries[2];
-        struct ipt_error term;
-} initial_table __net_initdata = {
-        .repl = {
-                .name = "raw",
-                .valid_hooks = RAW_VALID_HOOKS,
-                .num_entries = 3,
-                .size = sizeof(struct ipt_standard) * 2 + sizeof(struct ipt_error),
-                .hook_entry = {
-                        [NF_INET_PRE_ROUTING] = 0,
-                        [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard)
-                },
-                .underflow = {
-                        [NF_INET_PRE_ROUTING] = 0,
-                        [NF_INET_LOCAL_OUT]  = sizeof(struct ipt_standard)
-                },
-        },
-        .entries = {
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* PRE_ROUTING */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
-        },
-        .term = IPT_ERROR_INIT,                 /* ERROR */
-};
-
 static const struct xt_table packet_raw = {
         .name = "raw",
         .valid_hooks =  RAW_VALID_HOOKS,
@@ -66,9 +39,14 @@ static struct nf_hook_ops *rawtable_ops __read_mostly;
 
 static int __net_init iptable_raw_net_init(struct net *net)
 {
-        /* Register table */
+        struct ipt_replace *repl;
+
+        repl = ipt_alloc_initial_table(&packet_raw);
+        if (repl == NULL)
+                return -ENOMEM;
         net->ipv4.iptable_raw =
-                ipt_register_table(net, &packet_raw, &initial_table.repl);
+                ipt_register_table(net, &packet_raw, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.iptable_raw))
                 return PTR_ERR(net->ipv4.iptable_raw);
         return 0;
diff --git a/net/ipv4/netfilter/iptable_security.c b/net/ipv4/netfilter/iptable_security.c
index b1bf3ca2c6c7..cce2f64e6f21 100644
--- a/net/ipv4/netfilter/iptable_security.c
+++ b/net/ipv4/netfilter/iptable_security.c
@@ -27,36 +27,6 @@ MODULE_DESCRIPTION("iptables security table, for MAC rules");
                                 (1 << NF_INET_FORWARD) | \
                                 (1 << NF_INET_LOCAL_OUT)
 
-static const struct
-{
-        struct ipt_replace repl;
-        struct ipt_standard entries[3];
-        struct ipt_error term;
-} initial_table __net_initdata = {
-        .repl = {
-                .name = "security",
-                .valid_hooks = SECURITY_VALID_HOOKS,
-                .num_entries = 4,
-                .size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
-                .hook_entry = {
-                        [NF_INET_LOCAL_IN]      = 0,
-                        [NF_INET_FORWARD]       = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 2,
-                },
-                .underflow = {
-                        [NF_INET_LOCAL_IN]      = 0,
-                        [NF_INET_FORWARD]       = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT]     = sizeof(struct ipt_standard) * 2,
-                },
-        },
-        .entries = {
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_IN */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* FORWARD */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
-        },
-        .term = IPT_ERROR_INIT,                 /* ERROR */
-};
-
 static const struct xt_table security_table = {
         .name           = "security",
         .valid_hooks    = SECURITY_VALID_HOOKS,
@@ -87,9 +57,14 @@ static struct nf_hook_ops *sectbl_ops __read_mostly;
 
 static int __net_init iptable_security_net_init(struct net *net)
 {
-        net->ipv4.iptable_security =
-                ipt_register_table(net, &security_table, &initial_table.repl);
+        struct ipt_replace *repl;
 
+        repl = ipt_alloc_initial_table(&security_table);
+        if (repl == NULL)
+                return -ENOMEM;
+        net->ipv4.iptable_security =
+                ipt_register_table(net, &security_table, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.iptable_security))
                 return PTR_ERR(net->ipv4.iptable_security);
 
diff --git a/net/ipv4/netfilter/nf_nat_rule.c b/net/ipv4/netfilter/nf_nat_rule.c
index 85da34fdc755..ab74cc0535e2 100644
--- a/net/ipv4/netfilter/nf_nat_rule.c
+++ b/net/ipv4/netfilter/nf_nat_rule.c
@@ -28,36 +28,6 @@
                          (1 << NF_INET_POST_ROUTING) | \
                          (1 << NF_INET_LOCAL_OUT))
 
-static const struct
-{
-        struct ipt_replace repl;
-        struct ipt_standard entries[3];
-        struct ipt_error term;
-} nat_initial_table __net_initdata = {
-        .repl = {
-                .name = "nat",
-                .valid_hooks = NAT_VALID_HOOKS,
-                .num_entries = 4,
-                .size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
-                .hook_entry = {
-                        [NF_INET_PRE_ROUTING] = 0,
-                        [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2
-                },
-                .underflow = {
-                        [NF_INET_PRE_ROUTING] = 0,
-                        [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard),
-                        [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 2
-                },
-        },
-        .entries = {
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* PRE_ROUTING */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* POST_ROUTING */
-                IPT_STANDARD_INIT(NF_ACCEPT),   /* LOCAL_OUT */
-        },
-        .term = IPT_ERROR_INIT,                 /* ERROR */
-};
-
 static const struct xt_table nat_table = {
         .name           = "nat",
         .valid_hooks    = NAT_VALID_HOOKS,
@@ -186,8 +156,13 @@ static struct xt_target ipt_dnat_reg __read_mostly = {
 
 static int __net_init nf_nat_rule_net_init(struct net *net)
 {
-        net->ipv4.nat_table = ipt_register_table(net, &nat_table,
-                                                 &nat_initial_table.repl);
+        struct ipt_replace *repl;
+
+        repl = ipt_alloc_initial_table(&nat_table);
+        if (repl == NULL)
+                return -ENOMEM;
+        net->ipv4.nat_table = ipt_register_table(net, &nat_table, repl);
+        kfree(repl);
         if (IS_ERR(net->ipv4.nat_table))
                 return PTR_ERR(net->ipv4.nat_table);
         return 0;