netfilter: add cttimeout infrastructure for fine timeout tuning

This patch adds the infrastructure to add fine timeout tuning
over nfnetlink. Now you can use the NFNL_SUBSYS_CTNETLINK_TIMEOUT
subsystem to create/delete/dump timeout objects that contain some
specific timeout policy for one flow.

The follow up patches will allow you attach timeout policy object
to conntrack via the CT target and the conntrack extension
infrastructure.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 70 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_proto_dccp.c b/net/netfilter/nf_conntrack_proto_dccp.c
index 8ea3359..24fdce2 100644
--- a/net/netfilter/nf_conntrack_proto_dccp.c
+++ b/net/netfilter/nf_conntrack_proto_dccp.c
@@ -706,8 +706,60 @@ static int dccp_nlattr_size(void)
 	return nla_total_size(0)	/* CTA_PROTOINFO_DCCP */
 		+ nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
 }
+
 #endif
 
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_cttimeout.h>
+
+static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[], void *data)
+{
+	struct dccp_net *dn = dccp_pernet(&init_net);
+	unsigned int *timeouts = data;
+	int i;
+
+	/* set default DCCP timeouts. */
+	for (i=0; i<CT_DCCP_MAX; i++)
+		timeouts[i] = dn->dccp_timeout[i];
+
+	/* there's a 1:1 mapping between attributes and protocol states. */
+	for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
+		if (tb[i]) {
+			timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
+		}
+	}
+	return 0;
+}
+
+static int
+dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
+{
+        const unsigned int *timeouts = data;
+	int i;
+
+	for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++)
+		NLA_PUT_BE32(skb, i, htonl(timeouts[i] / HZ));
+
+	return 0;
+
+nla_put_failure:
+	return -ENOSPC;
+}
+
+static const struct nla_policy
+dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = {
+	[CTA_TIMEOUT_DCCP_REQUEST]	= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_RESPOND]	= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_PARTOPEN]	= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_OPEN]		= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_CLOSEREQ]	= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_CLOSING]	= { .type = NLA_U32 },
+	[CTA_TIMEOUT_DCCP_TIMEWAIT]	= { .type = NLA_U32 },
+};
+#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
+
 #ifdef CONFIG_SYSCTL
 /* template, data assigned later */
 static struct ctl_table dccp_sysctl_table[] = {
@@ -784,6 +836,15 @@ static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
 	.nlattr_to_tuple	= nf_ct_port_nlattr_to_tuple,
 	.nla_policy		= nf_ct_port_nla_policy,
 #endif
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
+	.ctnl_timeout		= {
+		.nlattr_to_obj	= dccp_timeout_nlattr_to_obj,
+		.obj_to_nlattr	= dccp_timeout_obj_to_nlattr,
+		.nlattr_max	= CTA_TIMEOUT_DCCP_MAX,
+		.obj_size	= sizeof(unsigned int) * CT_DCCP_MAX,
+		.nla_policy	= dccp_timeout_nla_policy,
+	},
+#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 };
 
 static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
@@ -807,6 +868,15 @@ static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
 	.nlattr_to_tuple	= nf_ct_port_nlattr_to_tuple,
 	.nla_policy		= nf_ct_port_nla_policy,
 #endif
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
+	.ctnl_timeout		= {
+		.nlattr_to_obj	= dccp_timeout_nlattr_to_obj,
+		.obj_to_nlattr	= dccp_timeout_obj_to_nlattr,
+		.nlattr_max	= CTA_TIMEOUT_DCCP_MAX,
+		.obj_size	= sizeof(unsigned int) * CT_DCCP_MAX,
+		.nla_policy	= dccp_timeout_nla_policy,
+	},
+#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 };
 
 static __net_init int dccp_net_init(struct net *net)