[PATCH net-next 12/26] netfilter: conntrack: make nf_conntrack_id callable without a module dependency

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Florian Westphal <fw@strlen.de>

While nf_conntrack_id() doesn't need any functionaliy from conntrack, it
does reside in nf_conntrack_core.c -- callers add a module
dependency on conntrack.

Followup patch will need to compute the conntrack id from nf_tables_trace.c
to include it in nf_trace messages emitted to userspace via netlink.

I don't want to introduce a module dependency between nf_tables and
conntrack for this.

Since trace is slowpath, the added indirection is ok.

One alternative is to move nf_conntrack_id to the netfilter/core.c,
but I don't see a compelling reason so far.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/netfilter.h         | 1 +
 net/netfilter/nf_conntrack_core.c | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 892d12823ed4..20947f2c685b 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -470,6 +470,7 @@ struct nf_ct_hook {
 	void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb);
 	void (*set_closing)(struct nf_conntrack *nfct);
 	int (*confirm)(struct sk_buff *skb);
+	u32 (*get_id)(const struct nf_conntrack *nfct);
 };
 extern const struct nf_ct_hook __rcu *nf_ct_hook;
 
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index de8d50af9b5b..201d3c4ec623 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -505,6 +505,11 @@ u32 nf_ct_get_id(const struct nf_conn *ct)
 }
 EXPORT_SYMBOL_GPL(nf_ct_get_id);
 
+static u32 nf_conntrack_get_id(const struct nf_conntrack *nfct)
+{
+	return nf_ct_get_id(nf_ct_to_nf_conn(nfct));
+}
+
 static void
 clean_from_lists(struct nf_conn *ct)
 {
@@ -2710,6 +2715,7 @@ static const struct nf_ct_hook nf_conntrack_hook = {
 	.attach		= nf_conntrack_attach,
 	.set_closing	= nf_conntrack_set_closing,
 	.confirm	= __nf_conntrack_confirm,
+	.get_id		= nf_conntrack_get_id,
 };
 
 void nf_conntrack_init_end(void)
-- 
2.30.2