[PATCH 15/52] netfilter: reduce hook array sizes to what is needed

[Pablo Neira Ayuso]

From: Florian Westphal <f...@strlen.de>

Not all families share the same hook count, adjust sizes to what is
needed.

struct net before:
/* size: 6592, cachelines: 103, members: 46 */
after:
/* size: 5952, cachelines: 93, members: 46 */

Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 include/net/netns/netfilter.h | 10 +++++-----
 net/netfilter/core.c          | 24 +++++++++++++++++-------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/include/net/netns/netfilter.h b/include/net/netns/netfilter.h
index b39c563c2fce..8f756a4b9205 100644
--- a/include/net/netns/netfilter.h
+++ b/include/net/netns/netfilter.h
@@ -17,11 +17,11 @@ struct netns_nf {
 #ifdef CONFIG_SYSCTL
        struct ctl_table_header *nf_log_dir_header;
 #endif
-       struct nf_hook_entries __rcu *hooks_ipv4[NF_MAX_HOOKS];
-       struct nf_hook_entries __rcu *hooks_ipv6[NF_MAX_HOOKS];
-       struct nf_hook_entries __rcu *hooks_arp[NF_MAX_HOOKS];
-       struct nf_hook_entries __rcu *hooks_bridge[NF_MAX_HOOKS];
-       struct nf_hook_entries __rcu *hooks_decnet[NF_MAX_HOOKS];
+       struct nf_hook_entries __rcu *hooks_ipv4[NF_INET_NUMHOOKS];
+       struct nf_hook_entries __rcu *hooks_ipv6[NF_INET_NUMHOOKS];
+       struct nf_hook_entries __rcu *hooks_arp[NF_ARP_NUMHOOKS];
+       struct nf_hook_entries __rcu *hooks_bridge[NF_INET_NUMHOOKS];
+       struct nf_hook_entries __rcu *hooks_decnet[NF_DN_NUMHOOKS];
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
        bool                    defrag_ipv4;
 #endif
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index a6eaaf303be8..43643427b560 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -268,14 +268,24 @@ static struct nf_hook_entries __rcu 
**nf_hook_entry_head(struct net *net, const
        case NFPROTO_NETDEV:
                break;
        case NFPROTO_ARP:
+               if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_arp) <= reg->hooknum))
+                       return NULL;
                return net->nf.hooks_arp + reg->hooknum;
        case NFPROTO_BRIDGE:
+               if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_bridge) <= 
reg->hooknum))
+                       return NULL;
                return net->nf.hooks_bridge + reg->hooknum;
        case NFPROTO_IPV4:
+               if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= 
reg->hooknum))
+                       return NULL;
                return net->nf.hooks_ipv4 + reg->hooknum;
        case NFPROTO_IPV6:
+               if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv6) <= 
reg->hooknum))
+                       return NULL;
                return net->nf.hooks_ipv6 + reg->hooknum;
        case NFPROTO_DECNET:
+               if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_decnet) <= 
reg->hooknum))
+                       return NULL;
                return net->nf.hooks_decnet + reg->hooknum;
        default:
                WARN_ON_ONCE(1);
@@ -549,21 +559,21 @@ void (*nf_nat_decode_session_hook)(struct sk_buff *, 
struct flowi *);
 EXPORT_SYMBOL(nf_nat_decode_session_hook);
 #endif
 
-static void __net_init __netfilter_net_init(struct nf_hook_entries 
*e[NF_MAX_HOOKS])
+static void __net_init __netfilter_net_init(struct nf_hook_entries **e, int 
max)
 {
        int h;
 
-       for (h = 0; h < NF_MAX_HOOKS; h++)
+       for (h = 0; h < max; h++)
                RCU_INIT_POINTER(e[h], NULL);
 }
 
 static int __net_init netfilter_net_init(struct net *net)
 {
-       __netfilter_net_init(net->nf.hooks_ipv4);
-       __netfilter_net_init(net->nf.hooks_ipv6);
-       __netfilter_net_init(net->nf.hooks_arp);
-       __netfilter_net_init(net->nf.hooks_bridge);
-       __netfilter_net_init(net->nf.hooks_decnet);
+       __netfilter_net_init(net->nf.hooks_ipv4, 
ARRAY_SIZE(net->nf.hooks_ipv4));
+       __netfilter_net_init(net->nf.hooks_ipv6, 
ARRAY_SIZE(net->nf.hooks_ipv6));
+       __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
+       __netfilter_net_init(net->nf.hooks_bridge, 
ARRAY_SIZE(net->nf.hooks_bridge));
+       __netfilter_net_init(net->nf.hooks_decnet, 
ARRAY_SIZE(net->nf.hooks_decnet));
 
 #ifdef CONFIG_PROC_FS
        net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
-- 
2.11.0

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