netfilter: nfnetlink_queue: fix compilation with NF_CONNTRACK disabled

In "9cb0176 netfilter: add glue code to integrate nfnetlink_queue and ctnetlink"
the compilation with NF_CONNTRACK disabled is broken. This patch fixes this
issue.

I have moved the conntrack part into nfnetlink_queue_ct.c to avoid
peppering the entire nfnetlink_queue.c code with ifdefs.

I also needed to rename nfnetlink_queue.c to nfnetlink_queue_pkt.c
to update the net/netfilter/Makefile to support conditional compilation
of the conntrack integration.

This patch also adds CONFIG_NETFILTER_QUEUE_CT in case you want to explicitly
disable the integration between nf_conntrack and nfnetlink_queue.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 97 insertions, 0 deletions

diff --git a/net/netfilter/nfnetlink_queue_ct.c b/net/netfilter/nfnetlink_queue_ct.c
new file mode 100644
index 000000000000..68ef550066f5
--- /dev/null
+++ b/net/netfilter/nfnetlink_queue_ct.c
@@ -0,0 +1,97 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_queue.h>
+#include <net/netfilter/nf_conntrack.h>
+
+struct nf_conn *nfqnl_ct_get(struct sk_buff *entskb, size_t *size,
+			     enum ip_conntrack_info *ctinfo)
+{
+	struct nfq_ct_hook *nfq_ct;
+	struct nf_conn *ct;
+
+	/* rcu_read_lock()ed by __nf_queue already. */
+	nfq_ct = rcu_dereference(nfq_ct_hook);
+	if (nfq_ct == NULL)
+		return NULL;
+
+	ct = nf_ct_get(entskb, ctinfo);
+	if (ct) {
+		if (!nf_ct_is_untracked(ct))
+			*size += nfq_ct->build_size(ct);
+		else
+			ct = NULL;
+	}
+	return ct;
+}
+
+struct nf_conn *
+nfqnl_ct_parse(const struct sk_buff *skb, const struct nlattr *attr,
+	       enum ip_conntrack_info *ctinfo)
+{
+	struct nfq_ct_hook *nfq_ct;
+	struct nf_conn *ct;
+
+	/* rcu_read_lock()ed by __nf_queue already. */
+	nfq_ct = rcu_dereference(nfq_ct_hook);
+	if (nfq_ct == NULL)
+		return NULL;
+
+	ct = nf_ct_get(skb, ctinfo);
+	if (ct && !nf_ct_is_untracked(ct))
+		nfq_ct->parse(attr, ct);
+
+	return ct;
+}
+
+int nfqnl_ct_put(struct sk_buff *skb, struct nf_conn *ct,
+		 enum ip_conntrack_info ctinfo)
+{
+	struct nfq_ct_hook *nfq_ct;
+	struct nlattr *nest_parms;
+	u_int32_t tmp;
+
+	nfq_ct = rcu_dereference(nfq_ct_hook);
+	if (nfq_ct == NULL)
+		return 0;
+
+	nest_parms = nla_nest_start(skb, NFQA_CT | NLA_F_NESTED);
+	if (!nest_parms)
+		goto nla_put_failure;
+
+	if (nfq_ct->build(skb, ct) < 0)
+		goto nla_put_failure;
+
+	nla_nest_end(skb, nest_parms);
+
+	tmp = ctinfo;
+	if (nla_put_be32(skb, NFQA_CT_INFO, htonl(tmp)))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+void nfqnl_ct_seq_adjust(struct sk_buff *skb, struct nf_conn *ct,
+			 enum ip_conntrack_info ctinfo, int diff)
+{
+	struct nfq_ct_hook *nfq_ct;
+
+	nfq_ct = rcu_dereference(nfq_ct_hook);
+	if (nfq_ct == NULL)
+		return;
+
+	if ((ct->status & IPS_NAT_MASK) && diff)
+		nfq_ct->seq_adjust(skb, ct, ctinfo, diff);
+}