netfilter: ctnetlink: remove get_ct indirection

Use nf_ct_get() directly, its a small inline helper without dependencies.

Add CONFIG_NF_CONNTRACK guards to elide the relevant part when conntrack
isn't available at all.

v2: add ifdef guard around nf_ct_get call (kernel test robot)
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/linux/netfilter.h

@@ -463,8 +463,6 @@ extern struct nf_ct_hook __rcu *nf_ct_hook;
 struct nlattr;
 
 struct nfnl_ct_hook {
-	struct nf_conn *(*get_ct)(const struct sk_buff *skb,
-				  enum ip_conntrack_info *ctinfo);
 	size_t (*build_size)(const struct nf_conn *ct);
 	int (*build)(struct sk_buff *skb, struct nf_conn *ct,
 		     enum ip_conntrack_info ctinfo,

net/netfilter/nf_conntrack_netlink.c

@@ -2686,12 +2686,6 @@ ctnetlink_glue_build_size(const struct nf_conn *ct)
 	       ;
 }
 
-static struct nf_conn *ctnetlink_glue_get_ct(const struct sk_buff *skb,
-					     enum ip_conntrack_info *ctinfo)
-{
-	return nf_ct_get(skb, ctinfo);
-}
-
 static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct)
 {
 	const struct nf_conntrack_zone *zone;
@@ -2925,7 +2919,6 @@ static void ctnetlink_glue_seqadj(struct sk_buff *skb, struct nf_conn *ct,
 }
 
 static struct nfnl_ct_hook ctnetlink_glue_hook = {
-	.get_ct		= ctnetlink_glue_get_ct,
 	.build_size	= ctnetlink_glue_build_size,
 	.build		= ctnetlink_glue_build,
 	.parse		= ctnetlink_glue_parse,

net/netfilter/nfnetlink_log.c

@@ -43,6 +43,10 @@
 #include "../bridge/br_private.h"
 #endif
 
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+#include <net/netfilter/nf_conntrack.h>
+#endif
+
 #define NFULNL_COPY_DISABLED	0xff
 #define NFULNL_NLBUFSIZ_DEFAULT	NLMSG_GOODSIZE
 #define NFULNL_TIMEOUT_DEFAULT 	100	/* every second */
@@ -733,14 +737,16 @@ nfulnl_log_packet(struct net *net,
 		size += nla_total_size(sizeof(u_int32_t));
 	if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 		size += nla_total_size(sizeof(u_int32_t));
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 		nfnl_ct = rcu_dereference(nfnl_ct_hook);
 		if (nfnl_ct != NULL) {
-			ct = nfnl_ct->get_ct(skb, &ctinfo);
+			ct = nf_ct_get(skb, &ctinfo);
 			if (ct != NULL)
 				size += nfnl_ct->build_size(ct);
 		}
 	}
+#endif
 	if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
 		size += nfulnl_get_bridge_size(skb);
 

net/netfilter/nfnetlink_queue.c

@@ -444,13 +444,15 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 
 	nfnl_ct = rcu_dereference(nfnl_ct_hook);
 
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	if (queue->flags & NFQA_CFG_F_CONNTRACK) {
 		if (nfnl_ct != NULL) {
-			ct = nfnl_ct->get_ct(entskb, &ctinfo);
+			ct = nf_ct_get(entskb, &ctinfo);
 			if (ct != NULL)
 				size += nfnl_ct->build_size(ct);
 		}
 	}
+#endif
 
 	if (queue->flags & NFQA_CFG_F_UID_GID) {
 		size += (nla_total_size(sizeof(u_int32_t))	/* uid */
@@ -1104,9 +1106,10 @@ static struct nf_conn *nfqnl_ct_parse(struct nfnl_ct_hook *nfnl_ct,
 				      struct nf_queue_entry *entry,
 				      enum ip_conntrack_info *ctinfo)
 {
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	struct nf_conn *ct;
 
-	ct = nfnl_ct->get_ct(entry->skb, ctinfo);
+	ct = nf_ct_get(entry->skb, ctinfo);
 	if (ct == NULL)
 		return NULL;
 
@@ -1118,6 +1121,9 @@ static struct nf_conn *nfqnl_ct_parse(struct nfnl_ct_hook *nfnl_ct,
 				      NETLINK_CB(entry->skb).portid,
 				      nlmsg_report(nlh));
 	return ct;
+#else
+	return NULL;
+#endif
 }
 
 static int nfqa_parse_bridge(struct nf_queue_entry *entry,