1 files changed, 333 insertions, 0 deletions
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
new file mode 100644
index 000000000..6988a9cf4
--- /dev/null
+++ b/net/sched/act_sample.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * net/sched/act_sample.c - Packet sampling tc action
+ * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <net/net_namespace.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <linux/tc_act/tc_sample.h>
+#include <net/tc_act/tc_sample.h>
+#include <net/psample.h>
+#include <net/pkt_cls.h>
+
+#include <linux/if_arp.h>
+
+static unsigned int sample_net_id;
+static struct tc_action_ops act_sample_ops;
+
+static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
+	[TCA_SAMPLE_PARMS]		= { .len = sizeof(struct tc_sample) },
+	[TCA_SAMPLE_RATE]		= { .type = NLA_U32 },
+	[TCA_SAMPLE_TRUNC_SIZE]		= { .type = NLA_U32 },
+	[TCA_SAMPLE_PSAMPLE_GROUP]	= { .type = NLA_U32 },
+};
+
+static int tcf_sample_init(struct net *net, struct nlattr *nla,
+			   struct nlattr *est, struct tc_action **a, int ovr,
+			   int bind, bool rtnl_held, struct tcf_proto *tp,
+			   u32 flags, struct netlink_ext_ack *extack)
+{
+	struct tc_action_net *tn = net_generic(net, sample_net_id);
+	struct nlattr *tb[TCA_SAMPLE_MAX + 1];
+	struct psample_group *psample_group;
+	u32 psample_group_num, rate, index;
+	struct tcf_chain *goto_ch = NULL;
+	struct tc_sample *parm;
+	struct tcf_sample *s;
+	bool exists = false;
+	int ret, err;
+
+	if (!nla)
+		return -EINVAL;
+	ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
+					  sample_policy, NULL);
+	if (ret < 0)
+		return ret;
+
+	if (!tb[TCA_SAMPLE_PARMS])
+		return -EINVAL;
+
+	parm = nla_data(tb[TCA_SAMPLE_PARMS]);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
+	if (exists && bind)
+		return 0;
+
+	if (!exists) {
+		ret = tcf_idr_create(tn, index, est, a,
+				     &act_sample_ops, bind, true, flags);
+		if (ret) {
+			tcf_idr_cleanup(tn, index);
+			return ret;
+		}
+		ret = ACT_P_CREATED;
+	} else if (!ovr) {
+		tcf_idr_release(*a, bind);
+		return -EEXIST;
+	}
+
+	if (!tb[TCA_SAMPLE_RATE] || !tb[TCA_SAMPLE_PSAMPLE_GROUP]) {
+		NL_SET_ERR_MSG(extack, "sample rate and group are required");
+		err = -EINVAL;
+		goto release_idr;
+	}
+
+	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
+	if (err < 0)
+		goto release_idr;
+
+	rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
+	if (!rate) {
+		NL_SET_ERR_MSG(extack, "invalid sample rate");
+		err = -EINVAL;
+		goto put_chain;
+	}
+	psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
+	psample_group = psample_group_get(net, psample_group_num);
+	if (!psample_group) {
+		err = -ENOMEM;
+		goto put_chain;
+	}
+
+	s = to_sample(*a);
+
+	spin_lock_bh(&s->tcf_lock);
+	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
+	s->rate = rate;
+	s->psample_group_num = psample_group_num;
+	psample_group = rcu_replace_pointer(s->psample_group, psample_group,
+					    lockdep_is_held(&s->tcf_lock));
+
+	if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
+		s->truncate = true;
+		s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
+	}
+	spin_unlock_bh(&s->tcf_lock);
+
+	if (psample_group)
+		psample_group_put(psample_group);
+	if (goto_ch)
+		tcf_chain_put_by_act(goto_ch);
+
+	return ret;
+put_chain:
+	if (goto_ch)
+		tcf_chain_put_by_act(goto_ch);
+release_idr:
+	tcf_idr_release(*a, bind);
+	return err;
+}
+
+static void tcf_sample_cleanup(struct tc_action *a)
+{
+	struct tcf_sample *s = to_sample(a);
+	struct psample_group *psample_group;
+
+	/* last reference to action, no need to lock */
+	psample_group = rcu_dereference_protected(s->psample_group, 1);
+	RCU_INIT_POINTER(s->psample_group, NULL);
+	if (psample_group)
+		psample_group_put(psample_group);
+}
+
+static bool tcf_sample_dev_ok_push(struct net_device *dev)
+{
+	switch (dev->type) {
+	case ARPHRD_TUNNEL:
+	case ARPHRD_TUNNEL6:
+	case ARPHRD_SIT:
+	case ARPHRD_IPGRE:
+	case ARPHRD_IP6GRE:
+	case ARPHRD_VOID:
+	case ARPHRD_NONE:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
+			  struct tcf_result *res)
+{
+	struct tcf_sample *s = to_sample(a);
+	struct psample_group *psample_group;
+	int retval;
+	int size;
+	int iif;
+	int oif;
+
+	tcf_lastuse_update(&s->tcf_tm);
+	bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
+	retval = READ_ONCE(s->tcf_action);
+
+	psample_group = rcu_dereference_bh(s->psample_group);
+
+	/* randomly sample packets according to rate */
+	if (psample_group && (prandom_u32() % s->rate == 0)) {
+		if (!skb_at_tc_ingress(skb)) {
+			iif = skb->skb_iif;
+			oif = skb->dev->ifindex;
+		} else {
+			iif = skb->dev->ifindex;
+			oif = 0;
+		}
+
+		/* on ingress, the mac header gets popped, so push it back */
+		if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
+			skb_push(skb, skb->mac_len);
+
+		size = s->truncate ? s->trunc_size : skb->len;
+		psample_sample_packet(psample_group, skb, size, iif, oif,
+				      s->rate);
+
+		if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
+			skb_pull(skb, skb->mac_len);
+	}
+
+	return retval;
+}
+
+static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
+			   int bind, int ref)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tcf_sample *s = to_sample(a);
+	struct tc_sample opt = {
+		.index      = s->tcf_index,
+		.refcnt     = refcount_read(&s->tcf_refcnt) - ref,
+		.bindcnt    = atomic_read(&s->tcf_bindcnt) - bind,
+	};
+	struct tcf_t t;
+
+	spin_lock_bh(&s->tcf_lock);
+	opt.action = s->tcf_action;
+	if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
+		goto nla_put_failure;
+
+	tcf_tm_dump(&t, &s->tcf_tm);
+	if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
+		goto nla_put_failure;
+
+	if (s->truncate)
+		if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
+			goto nla_put_failure;
+
+	if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
+		goto nla_put_failure;
+	spin_unlock_bh(&s->tcf_lock);
+
+	return skb->len;
+
+nla_put_failure:
+	spin_unlock_bh(&s->tcf_lock);
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int tcf_sample_walker(struct net *net, struct sk_buff *skb,
+			     struct netlink_callback *cb, int type,
+			     const struct tc_action_ops *ops,
+			     struct netlink_ext_ack *extack)
+{
+	struct tc_action_net *tn = net_generic(net, sample_net_id);
+
+	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
+}
+
+static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, sample_net_id);
+
+	return tcf_idr_search(tn, a, index);
+}
+
+static void tcf_psample_group_put(void *priv)
+{
+	struct psample_group *group = priv;
+
+	psample_group_put(group);
+}
+
+static struct psample_group *
+tcf_sample_get_group(const struct tc_action *a,
+		     tc_action_priv_destructor *destructor)
+{
+	struct tcf_sample *s = to_sample(a);
+	struct psample_group *group;
+
+	group = rcu_dereference_protected(s->psample_group,
+					  lockdep_is_held(&s->tcf_lock));
+	if (group) {
+		psample_group_take(group);
+		*destructor = tcf_psample_group_put;
+	}
+
+	return group;
+}
+
+static struct tc_action_ops act_sample_ops = {
+	.kind	  = "sample",
+	.id	  = TCA_ID_SAMPLE,
+	.owner	  = THIS_MODULE,
+	.act	  = tcf_sample_act,
+	.dump	  = tcf_sample_dump,
+	.init	  = tcf_sample_init,
+	.cleanup  = tcf_sample_cleanup,
+	.walk	  = tcf_sample_walker,
+	.lookup	  = tcf_sample_search,
+	.get_psample_group = tcf_sample_get_group,
+	.size	  = sizeof(struct tcf_sample),
+};
+
+static __net_init int sample_init_net(struct net *net)
+{
+	struct tc_action_net *tn = net_generic(net, sample_net_id);
+
+	return tc_action_net_init(net, tn, &act_sample_ops);
+}
+
+static void __net_exit sample_exit_net(struct list_head *net_list)
+{
+	tc_action_net_exit(net_list, sample_net_id);
+}
+
+static struct pernet_operations sample_net_ops = {
+	.init = sample_init_net,
+	.exit_batch = sample_exit_net,
+	.id   = &sample_net_id,
+	.size = sizeof(struct tc_action_net),
+};
+
+static int __init sample_init_module(void)
+{
+	return tcf_register_action(&act_sample_ops, &sample_net_ops);
+}
+
+static void __exit sample_cleanup_module(void)
+{
+	tcf_unregister_action(&act_sample_ops, &sample_net_ops);
+}
+
+module_init(sample_init_module);
+module_exit(sample_cleanup_module);
+
+MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
+MODULE_DESCRIPTION("Packet sampling action");
+MODULE_LICENSE("GPL v2");