[net-next,v3,1/1] net: sched: Introduce connmark action

diff --git a/include/net/tc_act/tc_connmark.h b/include/net/tc_act/tc_connmark.h
new file mode 100644
index 0000000..5c1104c
--- /dev/null
+++ b/include/net/tc_act/tc_connmark.h
@@ -0,0 +1,14 @@ 
+#ifndef __NET_TC_CONNMARK_H
+#define __NET_TC_CONNMARK_H
+
+#include <net/act_api.h>
+
+struct tcf_connmark_info {
+	struct tcf_common common;
+	u16 zone;
+};
+
+#define to_connmark(a) \
+	container_of(a->priv, struct tcf_connmark_info, common)
+
+#endif /* __NET_TC_CONNMARK_H */
diff --git a/include/uapi/linux/tc_act/tc_connmark.h b/include/uapi/linux/tc_act/tc_connmark.h
new file mode 100644
index 0000000..994b097
--- /dev/null
+++ b/include/uapi/linux/tc_act/tc_connmark.h
@@ -0,0 +1,22 @@ 
+#ifndef __UAPI_TC_CONNMARK_H
+#define __UAPI_TC_CONNMARK_H
+
+#include <linux/types.h>
+#include <linux/pkt_cls.h>
+
+#define TCA_ACT_CONNMARK 14
+
+struct tc_connmark {
+	tc_gen;
+	__u16 zone;
+};
+
+enum {
+	TCA_CONNMARK_UNSPEC,
+	TCA_CONNMARK_PARMS,
+	TCA_CONNMARK_TM,
+	__TCA_CONNMARK_MAX
+};
+#define TCA_CONNMARK_MAX (__TCA_CONNMARK_MAX - 1)
+
+#endif
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index c54c9d9..db20cae 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -698,6 +698,17 @@  config NET_ACT_VLAN
 	  To compile this code as a module, choose M here: the
 	  module will be called act_vlan.
 
+config NET_ACT_CONNMARK
+        tristate "Netfilter Connection Mark Retriever"
+        depends on NET_CLS_ACT && NETFILTER && IP_NF_IPTABLES
+        ---help---
+	  Say Y here to allow retrieving of conn mark
+
+	  If unsure, say N.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called act_connmark.
+
 config NET_CLS_IND
 	bool "Incoming device classification"
 	depends on NET_CLS_U32 || NET_CLS_FW
diff --git a/net/sched/Makefile b/net/sched/Makefile
index 679f24a..47304cd 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -17,6 +17,7 @@  obj-$(CONFIG_NET_ACT_SIMP)	+= act_simple.o
 obj-$(CONFIG_NET_ACT_SKBEDIT)	+= act_skbedit.o
 obj-$(CONFIG_NET_ACT_CSUM)	+= act_csum.o
 obj-$(CONFIG_NET_ACT_VLAN)	+= act_vlan.o
+obj-$(CONFIG_NET_ACT_CONNMARK)	+= act_connmark.o
 obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
 obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
 obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
new file mode 100644
index 0000000..8e47251
--- /dev/null
+++ b/net/sched/act_connmark.c
@@ -0,0 +1,192 @@ 
+/*
+ * net/sched/act_connmark.c  netfilter connmark retriever action
+ * skb mark is over-written
+ *
+ * Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/pkt_cls.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/act_api.h>
+#include <uapi/linux/tc_act/tc_connmark.h>
+#include <net/tc_act/tc_connmark.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+
+#define CONNMARK_TAB_MASK     3
+
+static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
+			struct tcf_result *res)
+{
+	const struct nf_conntrack_tuple_hash *thash;
+	struct nf_conntrack_tuple tuple;
+	enum ip_conntrack_info ctinfo;
+	struct tcf_connmark_info *ca = a->priv;
+	struct nf_conn *c;
+	int proto;
+
+	spin_lock(&ca->tcf_lock);
+	ca->tcf_tm.lastuse = jiffies;
+	bstats_update(&ca->tcf_bstats, skb);
+
+	if (skb->protocol == htons(ETH_P_IP)) {
+		if (skb->len < sizeof(struct iphdr))
+			goto out;
+
+		proto = NFPROTO_IPV4;
+	} else if (skb->protocol == htons(ETH_P_IPV6)) {
+		if (skb->len < sizeof(struct ipv6hdr))
+			goto out;
+
+		proto = NFPROTO_IPV6;
+	} else {
+		goto out;
+	}
+
+	c = nf_ct_get(skb, &ctinfo);
+	if (c) {
+		skb->mark = c->mark;
+		/* using overlimits stats to count how many packets marked */
+		ca->tcf_qstats.overlimits++;
+		nf_ct_put(c);
+		goto out;
+	}
+
+	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
+			       proto, &tuple))
+		goto out;
+
+	thash = nf_conntrack_find_get(dev_net(skb->dev), ca->zone, &tuple);
+	if (!thash)
+		goto out;
+
+	c = nf_ct_tuplehash_to_ctrack(thash);
+	/* using overlimits stats to count how many packets marked */
+	ca->tcf_qstats.overlimits++;
+	skb->mark = c->mark;
+	nf_ct_put(c);
+
+out:
+	skb->nfct = NULL;
+	spin_unlock(&ca->tcf_lock);
+	return ca->tcf_action;
+}
+
+static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
+	[TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
+};
+
+static int tcf_connmark_init(struct net *net, struct nlattr *nla,
+			     struct nlattr *est, struct tc_action *a,
+			     int ovr, int bind)
+{
+	struct nlattr *tb[TCA_CONNMARK_MAX + 1];
+	struct tcf_connmark_info *ci;
+	struct tc_connmark *parm;
+	int ret = 0;
+
+	if (!nla)
+		return -EINVAL;
+
+	ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
+	if (ret < 0)
+		return ret;
+
+	parm = nla_data(tb[TCA_CONNMARK_PARMS]);
+
+	if (!tcf_hash_check(parm->index, a, bind)) {
+		ret = tcf_hash_create(parm->index, est, a, sizeof(*ci), bind);
+		if (ret)
+			return ret;
+
+		ci = to_connmark(a);
+		ci->tcf_action = parm->action;
+		ci->zone = parm->zone;
+
+		tcf_hash_insert(a);
+		ret = ACT_P_CREATED;
+	} else {
+		ci = to_connmark(a);
+		if (bind)
+			return 0;
+		tcf_hash_release(a, bind);
+		if (!ovr)
+			return -EEXIST;
+		/* replacing action and zone */
+		ci->tcf_action = parm->action;
+		ci->zone = parm->zone;
+	}
+
+	return ret;
+}
+
+static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
+				    int bind, int ref)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tcf_connmark_info *ci = a->priv;
+
+	struct tc_connmark opt = {
+		.index   = ci->tcf_index,
+		.refcnt  = ci->tcf_refcnt - ref,
+		.bindcnt = ci->tcf_bindcnt - bind,
+		.action  = ci->tcf_action,
+		.zone   = ci->zone,
+	};
+	struct tcf_t t;
+
+	if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
+		goto nla_put_failure;
+
+	t.install = jiffies_to_clock_t(jiffies - ci->tcf_tm.install);
+	t.lastuse = jiffies_to_clock_t(jiffies - ci->tcf_tm.lastuse);
+	t.expires = jiffies_to_clock_t(ci->tcf_tm.expires);
+	if (nla_put(skb, TCA_CONNMARK_TM, sizeof(t), &t))
+		goto nla_put_failure;
+
+	return skb->len;
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static struct tc_action_ops act_connmark_ops = {
+	.kind		=	"connmark",
+	.type		=	TCA_ACT_CONNMARK,
+	.owner		=	THIS_MODULE,
+	.act		=	tcf_connmark,
+	.dump		=	tcf_connmark_dump,
+	.init		=	tcf_connmark_init,
+};
+
+static int __init connmark_init_module(void)
+{
+	return tcf_register_action(&act_connmark_ops, CONNMARK_TAB_MASK);
+}
+
+static void __exit connmark_cleanup_module(void)
+{
+	tcf_unregister_action(&act_connmark_ops);
+}
+
+module_init(connmark_init_module);
+module_exit(connmark_cleanup_module);
+MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
+MODULE_DESCRIPTION("Connection tracking mark restoring");
+MODULE_LICENSE("GPL");
+