[PATCH 2/5] netfilter: register sysctl table for gre

[Yafang Shao]

After this patch, there will be two sysctl knobs for GRE.

        net.netfilter.nf_conntrack_gre_timeout_replied = 180
        net.netfilter.nf_conntrack_gre_timeout_unreplied = 30

Signed-off-by: Yafang Shao <laoar.s...@gmail.com>
---
 net/netfilter/nf_conntrack_proto_gre.c | 43 +++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_proto_gre.c 
b/net/netfilter/nf_conntrack_proto_gre.c
index 2a5e56c..a70894e 100644
--- a/net/netfilter/nf_conntrack_proto_gre.c
+++ b/net/netfilter/nf_conntrack_proto_gre.c
@@ -320,9 +320,50 @@ static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
 };
 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 
+#ifdef CONFIG_SYSCTL
+static struct ctl_table gre_sysctl_table[] = {
+       {
+               .procname       = "nf_conntrack_gre_timeout_unreplied",
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_jiffies,
+       },
+       {
+               .procname       = "nf_conntrack_gre_timeout_replied",
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_jiffies,
+       },
+       {}
+};
+#endif /* CONFIG_SYSCTL */
+
+static int gre_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *nf,
+                                   struct netns_proto_gre *net_gre)
+{
+#ifdef CONFIG_SYSCTL
+       int i;
+
+       if (nf->ctl_table)
+               return 0;
+
+       nf->ctl_table = kmemdup(gre_sysctl_table,
+                               sizeof(gre_sysctl_table),
+                               GFP_KERNEL);
+       if (!nf->ctl_table)
+               return -ENOMEM;
+
+       for (i = 0; i < GRE_CT_MAX; i++)
+               nf->ctl_table[i].data = &net_gre->gre_timeouts[i];
+#endif
+
+       return 0;
+}
+
 static int gre_init_net(struct net *net)
 {
        struct netns_proto_gre *net_gre = gre_pernet(net);
+       struct nf_proto_net *nf = &net_gre->nf;
        int i;
 
        rwlock_init(&net_gre->keymap_lock);
@@ -330,7 +371,7 @@ static int gre_init_net(struct net *net)
        for (i = 0; i < GRE_CT_MAX; i++)
                net_gre->gre_timeouts[i] = gre_timeouts[i];
 
-       return 0;
+       return gre_kmemdup_sysctl_table(net, nf, net_gre);
 }
 
 /* protocol helper struct */
-- 
1.8.3.1