Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 535 insertions, 0 deletions

diff --git a/net/psample/psample.c b/net/psample/psample.c
new file mode 100644
index 000000000..c112e1f0c
--- /dev/null
+++ b/net/psample/psample.c
@@ -0,0 +1,535 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * net/psample/psample.c - Netlink channel for packet sampling
+ * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/module.h>
+#include <linux/timekeeping.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <net/psample.h>
+#include <linux/spinlock.h>
+#include <net/ip_tunnels.h>
+#include <net/dst_metadata.h>
+
+#define PSAMPLE_MAX_PACKET_SIZE 0xffff
+
+static LIST_HEAD(psample_groups_list);
+static DEFINE_SPINLOCK(psample_groups_lock);
+
+/* multicast groups */
+enum psample_nl_multicast_groups {
+	PSAMPLE_NL_MCGRP_CONFIG,
+	PSAMPLE_NL_MCGRP_SAMPLE,
+};
+
+static const struct genl_multicast_group psample_nl_mcgrps[] = {
+	[PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
+	[PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME,
+				      .flags = GENL_MCAST_CAP_NET_ADMIN, },
+};
+
+static struct genl_family psample_nl_family __ro_after_init;
+
+static int psample_group_nl_fill(struct sk_buff *msg,
+				 struct psample_group *group,
+				 enum psample_command cmd, u32 portid, u32 seq,
+				 int flags)
+{
+	void *hdr;
+	int ret;
+
+	hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+	if (ret < 0)
+		goto error;
+
+	ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
+	if (ret < 0)
+		goto error;
+
+	ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
+	if (ret < 0)
+		goto error;
+
+	genlmsg_end(msg, hdr);
+	return 0;
+
+error:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
+					   struct netlink_callback *cb)
+{
+	struct psample_group *group;
+	int start = cb->args[0];
+	int idx = 0;
+	int err;
+
+	spin_lock_bh(&psample_groups_lock);
+	list_for_each_entry(group, &psample_groups_list, list) {
+		if (!net_eq(group->net, sock_net(msg->sk)))
+			continue;
+		if (idx < start) {
+			idx++;
+			continue;
+		}
+		err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
+					    NETLINK_CB(cb->skb).portid,
+					    cb->nlh->nlmsg_seq, NLM_F_MULTI);
+		if (err)
+			break;
+		idx++;
+	}
+
+	spin_unlock_bh(&psample_groups_lock);
+	cb->args[0] = idx;
+	return msg->len;
+}
+
+static const struct genl_small_ops psample_nl_ops[] = {
+	{
+		.cmd = PSAMPLE_CMD_GET_GROUP,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.dumpit = psample_nl_cmd_get_group_dumpit,
+		/* can be retrieved by unprivileged users */
+	}
+};
+
+static struct genl_family psample_nl_family __ro_after_init = {
+	.name		= PSAMPLE_GENL_NAME,
+	.version	= PSAMPLE_GENL_VERSION,
+	.maxattr	= PSAMPLE_ATTR_MAX,
+	.netnsok	= true,
+	.module		= THIS_MODULE,
+	.mcgrps		= psample_nl_mcgrps,
+	.small_ops	= psample_nl_ops,
+	.n_small_ops	= ARRAY_SIZE(psample_nl_ops),
+	.resv_start_op	= PSAMPLE_CMD_GET_GROUP + 1,
+	.n_mcgrps	= ARRAY_SIZE(psample_nl_mcgrps),
+};
+
+static void psample_group_notify(struct psample_group *group,
+				 enum psample_command cmd)
+{
+	struct sk_buff *msg;
+	int err;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	if (!msg)
+		return;
+
+	err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
+	if (!err)
+		genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
+					PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
+	else
+		nlmsg_free(msg);
+}
+
+static struct psample_group *psample_group_create(struct net *net,
+						  u32 group_num)
+{
+	struct psample_group *group;
+
+	group = kzalloc_obj(*group, GFP_ATOMIC);
+	if (!group)
+		return NULL;
+
+	group->net = net;
+	group->group_num = group_num;
+	list_add_tail(&group->list, &psample_groups_list);
+
+	psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
+	return group;
+}
+
+static void psample_group_destroy(struct psample_group *group)
+{
+	psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
+	list_del(&group->list);
+	kfree_rcu(group, rcu);
+}
+
+static struct psample_group *
+psample_group_lookup(struct net *net, u32 group_num)
+{
+	struct psample_group *group;
+
+	list_for_each_entry(group, &psample_groups_list, list)
+		if ((group->group_num == group_num) && (group->net == net))
+			return group;
+	return NULL;
+}
+
+struct psample_group *psample_group_get(struct net *net, u32 group_num)
+{
+	struct psample_group *group;
+
+	spin_lock_bh(&psample_groups_lock);
+
+	group = psample_group_lookup(net, group_num);
+	if (!group) {
+		group = psample_group_create(net, group_num);
+		if (!group)
+			goto out;
+	}
+	group->refcount++;
+
+out:
+	spin_unlock_bh(&psample_groups_lock);
+	return group;
+}
+EXPORT_SYMBOL_GPL(psample_group_get);
+
+void psample_group_take(struct psample_group *group)
+{
+	spin_lock_bh(&psample_groups_lock);
+	group->refcount++;
+	spin_unlock_bh(&psample_groups_lock);
+}
+EXPORT_SYMBOL_GPL(psample_group_take);
+
+void psample_group_put(struct psample_group *group)
+{
+	spin_lock_bh(&psample_groups_lock);
+
+	if (--group->refcount == 0)
+		psample_group_destroy(group);
+
+	spin_unlock_bh(&psample_groups_lock);
+}
+EXPORT_SYMBOL_GPL(psample_group_put);
+
+#ifdef CONFIG_INET
+static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
+			      struct ip_tunnel_info *tun_info)
+{
+	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
+	const void *tun_opts = ip_tunnel_info_opts(tun_info);
+	const struct ip_tunnel_key *tun_key = &tun_info->key;
+	int tun_opts_len = tun_info->options_len;
+
+	if (test_bit(IP_TUNNEL_KEY_BIT, tun_key->tun_flags) &&
+	    nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
+			 PSAMPLE_TUNNEL_KEY_ATTR_PAD))
+		return -EMSGSIZE;
+
+	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
+		return -EMSGSIZE;
+
+	switch (tun_proto) {
+	case AF_INET:
+		if (tun_key->u.ipv4.src &&
+		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
+				    tun_key->u.ipv4.src))
+			return -EMSGSIZE;
+		if (tun_key->u.ipv4.dst &&
+		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
+				    tun_key->u.ipv4.dst))
+			return -EMSGSIZE;
+		break;
+	case AF_INET6:
+		if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
+		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
+				     &tun_key->u.ipv6.src))
+			return -EMSGSIZE;
+		if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
+		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
+				     &tun_key->u.ipv6.dst))
+			return -EMSGSIZE;
+		break;
+	}
+	if (tun_key->tos &&
+	    nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
+		return -EMSGSIZE;
+	if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
+		return -EMSGSIZE;
+	if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, tun_key->tun_flags) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
+		return -EMSGSIZE;
+	if (test_bit(IP_TUNNEL_CSUM_BIT, tun_key->tun_flags) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
+		return -EMSGSIZE;
+	if (tun_key->tp_src &&
+	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
+		return -EMSGSIZE;
+	if (tun_key->tp_dst &&
+	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
+		return -EMSGSIZE;
+	if (test_bit(IP_TUNNEL_OAM_BIT, tun_key->tun_flags) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
+		return -EMSGSIZE;
+	if (tun_opts_len) {
+		if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, tun_key->tun_flags) &&
+		    nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
+			    tun_opts_len, tun_opts))
+			return -EMSGSIZE;
+		else if (test_bit(IP_TUNNEL_ERSPAN_OPT_BIT,
+				  tun_key->tun_flags) &&
+			 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
+				 tun_opts_len, tun_opts))
+			return -EMSGSIZE;
+	}
+
+	return 0;
+}
+
+static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
+			    struct ip_tunnel_info *tun_info)
+{
+	struct nlattr *nla;
+	int err;
+
+	nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
+	if (!nla)
+		return -EMSGSIZE;
+
+	err = __psample_ip_tun_to_nlattr(skb, tun_info);
+	if (err) {
+		nla_nest_cancel(skb, nla);
+		return err;
+	}
+
+	nla_nest_end(skb, nla);
+
+	return 0;
+}
+
+static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
+{
+	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
+	const struct ip_tunnel_key *tun_key = &tun_info->key;
+	int tun_opts_len = tun_info->options_len;
+	int sum = nla_total_size(0);	/* PSAMPLE_ATTR_TUNNEL */
+
+	if (test_bit(IP_TUNNEL_KEY_BIT, tun_key->tun_flags))
+		sum += nla_total_size_64bit(sizeof(u64));
+
+	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
+		sum += nla_total_size(0);
+
+	switch (tun_proto) {
+	case AF_INET:
+		if (tun_key->u.ipv4.src)
+			sum += nla_total_size(sizeof(u32));
+		if (tun_key->u.ipv4.dst)
+			sum += nla_total_size(sizeof(u32));
+		break;
+	case AF_INET6:
+		if (!ipv6_addr_any(&tun_key->u.ipv6.src))
+			sum += nla_total_size(sizeof(struct in6_addr));
+		if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
+			sum += nla_total_size(sizeof(struct in6_addr));
+		break;
+	}
+	if (tun_key->tos)
+		sum += nla_total_size(sizeof(u8));
+	sum += nla_total_size(sizeof(u8));	/* TTL */
+	if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, tun_key->tun_flags))
+		sum += nla_total_size(0);
+	if (test_bit(IP_TUNNEL_CSUM_BIT, tun_key->tun_flags))
+		sum += nla_total_size(0);
+	if (tun_key->tp_src)
+		sum += nla_total_size(sizeof(u16));
+	if (tun_key->tp_dst)
+		sum += nla_total_size(sizeof(u16));
+	if (test_bit(IP_TUNNEL_OAM_BIT, tun_key->tun_flags))
+		sum += nla_total_size(0);
+	if (tun_opts_len) {
+		if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, tun_key->tun_flags))
+			sum += nla_total_size(tun_opts_len);
+		else if (test_bit(IP_TUNNEL_ERSPAN_OPT_BIT,
+				  tun_key->tun_flags))
+			sum += nla_total_size(tun_opts_len);
+	}
+
+	return sum;
+}
+#endif
+
+void psample_sample_packet(struct psample_group *group,
+			   const struct sk_buff *skb, u32 sample_rate,
+			   const struct psample_metadata *md)
+{
+	ktime_t tstamp = ktime_get_real();
+	int out_ifindex = md->out_ifindex;
+	int in_ifindex = md->in_ifindex;
+	u32 trunc_size = md->trunc_size;
+#ifdef CONFIG_INET
+	struct ip_tunnel_info *tun_info;
+#endif
+	struct sk_buff *nl_skb;
+	int data_len;
+	int meta_len;
+	void *data;
+	int ret;
+
+	if (!genl_has_listeners(&psample_nl_family, group->net,
+				PSAMPLE_NL_MCGRP_SAMPLE))
+		return;
+
+	meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+		   (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
+		   (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +
+		   (md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
+		   (md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
+		   nla_total_size(sizeof(u32)) +	/* sample_rate */
+		   nla_total_size(sizeof(u32)) +	/* orig_size */
+		   nla_total_size(sizeof(u32)) +	/* group_num */
+		   nla_total_size(sizeof(u32)) +	/* seq */
+		   nla_total_size_64bit(sizeof(u64)) +	/* timestamp */
+		   nla_total_size(sizeof(u16)) +	/* protocol */
+		   (md->user_cookie_len ?
+		    nla_total_size(md->user_cookie_len) : 0) + /* user cookie */
+		   (md->rate_as_probability ?
+		    nla_total_size(0) : 0);	/* rate as probability */
+
+#ifdef CONFIG_INET
+	tun_info = skb_tunnel_info(skb);
+	if (tun_info)
+		meta_len += psample_tunnel_meta_len(tun_info);
+#endif
+
+	data_len = min(skb->len, trunc_size);
+	if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
+		data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
+			    - NLA_ALIGNTO;
+
+	nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
+	if (unlikely(!nl_skb))
+		return;
+
+	data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
+			   PSAMPLE_CMD_SAMPLE);
+	if (unlikely(!data))
+		goto error;
+
+	if (in_ifindex) {
+		ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
+	if (out_ifindex) {
+		ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
+	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
+	if (unlikely(ret < 0))
+		goto error;
+
+	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
+	if (unlikely(ret < 0))
+		goto error;
+
+	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
+	if (unlikely(ret < 0))
+		goto error;
+
+	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
+	if (unlikely(ret < 0))
+		goto error;
+
+	if (md->out_tc_valid) {
+		ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
+	if (md->out_tc_occ_valid) {
+		ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC,
+					md->out_tc_occ, PSAMPLE_ATTR_PAD);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
+	if (md->latency_valid) {
+		ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY,
+					md->latency, PSAMPLE_ATTR_PAD);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
+	ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP,
+				ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD);
+	if (unlikely(ret < 0))
+		goto error;
+
+	ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO,
+			  be16_to_cpu(skb->protocol));
+	if (unlikely(ret < 0))
+		goto error;
+
+	if (data_len) {
+		int nla_len = nla_attr_size(data_len);
+		struct nlattr *nla;
+
+		nla = skb_put(nl_skb, nla_len);
+		nla->nla_type = PSAMPLE_ATTR_DATA;
+		nla->nla_len = nla_len;
+
+		if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
+			goto error;
+
+		skb_put_zero(nl_skb, nla_padlen(data_len));
+	}
+
+#ifdef CONFIG_INET
+	if (tun_info) {
+		ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+#endif
+
+	if (md->user_cookie && md->user_cookie_len &&
+	    nla_put(nl_skb, PSAMPLE_ATTR_USER_COOKIE, md->user_cookie_len,
+		    md->user_cookie))
+		goto error;
+
+	if (md->rate_as_probability &&
+	    nla_put_flag(nl_skb, PSAMPLE_ATTR_SAMPLE_PROBABILITY))
+		goto error;
+
+	genlmsg_end(nl_skb, data);
+	genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
+				PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
+
+	return;
+error:
+	pr_err_ratelimited("Could not create psample log message\n");
+	nlmsg_free(nl_skb);
+}
+EXPORT_SYMBOL_GPL(psample_sample_packet);
+
+static int __init psample_module_init(void)
+{
+	return genl_register_family(&psample_nl_family);
+}
+
+static void __exit psample_module_exit(void)
+{
+	genl_unregister_family(&psample_nl_family);
+}
+
+module_init(psample_module_init);
+module_exit(psample_module_exit);
+
+MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
+MODULE_DESCRIPTION("netlink channel for packet sampling");
+MODULE_LICENSE("GPL v2");