From: Florian Westphal <fw@strlen.de>
To: <netfilter-devel@vger.kernel.org>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, me@ubique.spb.ru,
Florian Westphal <fw@strlen.de>
Subject: [PATCH RFC nf-next 5/9] netfilter: reduce allowed hook count to 32
Date: Thu, 14 Oct 2021 14:10:42 +0200 [thread overview]
Message-ID: <20211014121046.29329-7-fw@strlen.de> (raw)
In-Reply-To: <20211014121046.29329-1-fw@strlen.de>
1k is huge and will mean we'd need to support tailcalls in the
nf_hook bpf converter.
We need about 5 insns per hook at this time, ignoring prologue/epilogue.
32 should be fine, typically even extreme cases need about 8 hooks per
hook location.
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/netfilter/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 3fd268afc13e..f4359179eba9 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -42,7 +42,7 @@ EXPORT_SYMBOL(nf_hooks_needed);
static DEFINE_MUTEX(nf_hook_mutex);
/* max hooks per family/hooknum */
-#define MAX_HOOK_COUNT 1024
+#define MAX_HOOK_COUNT 32
#define nf_entry_dereference(e) \
rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))
--
2.32.0
next prev parent reply other threads:[~2021-10-14 12:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 12:10 [PATCH RFC nf-next 0/9] netfilter: bpf base hook program generator Florian Westphal
2021-10-14 12:10 ` [PATCH 1/1] netfilter: add " Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 1/9] netfilter: nf_queue: carry index in hook state Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 2/9] netfilter: nat: split nat hook iteration into a helper Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 3/9] netfilter: remove hook index from nf_hook_slow arguments Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 4/9] netfilter: make hook functions accept only one argument Florian Westphal
2021-10-14 12:10 ` Florian Westphal [this message]
2021-10-14 12:10 ` [PATCH RFC nf-next 6/9] netfilter: add bpf base hook program generator Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 7/9] netfilter: core: do not rebuild bpf program on dying netns Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 8/9] netfilter: ingress: switch to invocation via bpf Florian Westphal
2021-10-14 12:10 ` [PATCH RFC nf-next 9/9] netfilter: hook_jit: add prog cache Florian Westphal
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