Merge branch 'mpls-packet-stats'

Robert Shearman says:

====================
mpls: Packet stats

This patchset records per-interface packet stats in the MPLS
forwarding path and exports them using a nest of attributes root at a
new IFLA_STATS_AF_SPEC attribute as part of RTM_GETSTATS messages:

[IFLA_STATS_AF_SPEC]
 -> [AF_MPLS]
  -> [MPLS_STATS_LINK]
   -> struct mpls_link_stats

The first patch adds the rtnl infrastructure for this, including a new
callbacks to per-AF ops of fill_stats_af and get_stats_af_size. The
second patch records MPLS stats and makes use of the infrastructure to
export them. The rtnl infrastructure could also be used to export IPv6
stats in the future.

Changes in v2:
 - make incrementing IPv6 stats in mpls_stats_inc_outucastpkts
   conditional on CONFIG_IPV6 to fix build with CONFIG_IPV6=n
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/rtnetlink.h

@@ -139,6 +139,10 @@ struct rtnl_af_ops {
 						    const struct nlattr *attr);
 	int			(*set_link_af)(struct net_device *dev,
 					       const struct nlattr *attr);
+
+	int			(*fill_stats_af)(struct sk_buff *skb,
+						 const struct net_device *dev);
+	size_t			(*get_stats_af_size)(const struct net_device *dev);
 };
 
 void __rtnl_af_unregister(struct rtnl_af_ops *ops);

include/uapi/linux/if_link.h

@@ -847,6 +847,7 @@ enum {
 	IFLA_STATS_LINK_XSTATS,
 	IFLA_STATS_LINK_XSTATS_SLAVE,
 	IFLA_STATS_LINK_OFFLOAD_XSTATS,
+	IFLA_STATS_AF_SPEC,
 	__IFLA_STATS_MAX,
 };
 

include/uapi/linux/mpls.h

@@ -43,4 +43,34 @@ struct mpls_label {
 
 #define MPLS_LABEL_FIRST_UNRESERVED	16 /* RFC3032 */
 
+/* These are embedded into IFLA_STATS_AF_SPEC:
+ * [IFLA_STATS_AF_SPEC]
+ * -> [AF_MPLS]
+ *    -> [MPLS_STATS_xxx]
+ *
+ * Attributes:
+ * [MPLS_STATS_LINK] = {
+ *     struct mpls_link_stats
+ * }
+ */
+enum {
+	MPLS_STATS_UNSPEC, /* also used as 64bit pad attribute */
+	MPLS_STATS_LINK,
+	__MPLS_STATS_MAX,
+};
+
+#define MPLS_STATS_MAX (__MPLS_STATS_MAX - 1)
+
+struct mpls_link_stats {
+	__u64	rx_packets;		/* total packets received	*/
+	__u64	tx_packets;		/* total packets transmitted	*/
+	__u64	rx_bytes;		/* total bytes received		*/
+	__u64	tx_bytes;		/* total bytes transmitted	*/
+	__u64	rx_errors;		/* bad packets received		*/
+	__u64	tx_errors;		/* packet transmit problems	*/
+	__u64	rx_dropped;		/* packet dropped on receive	*/
+	__u64	tx_dropped;		/* packet dropped on transmit	*/
+	__u64	rx_noroute;		/* no route for packet dest	*/
+};
+
 #endif /* _UAPI_MPLS_H */

net/core/rtnetlink.c

@@ -3829,6 +3829,39 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 		*idxattr = 0;
 	}
 
+	if (stats_attr_valid(filter_mask, IFLA_STATS_AF_SPEC, *idxattr)) {
+		struct rtnl_af_ops *af_ops;
+
+		*idxattr = IFLA_STATS_AF_SPEC;
+		attr = nla_nest_start(skb, IFLA_STATS_AF_SPEC);
+		if (!attr)
+			goto nla_put_failure;
+
+		list_for_each_entry(af_ops, &rtnl_af_ops, list) {
+			if (af_ops->fill_stats_af) {
+				struct nlattr *af;
+				int err;
+
+				af = nla_nest_start(skb, af_ops->family);
+				if (!af)
+					goto nla_put_failure;
+
+				err = af_ops->fill_stats_af(skb, dev);
+
+				if (err == -ENODATA)
+					nla_nest_cancel(skb, af);
+				else if (err < 0)
+					goto nla_put_failure;
+
+				nla_nest_end(skb, af);
+			}
+		}
+
+		nla_nest_end(skb, attr);
+
+		*idxattr = 0;
+	}
+
 	nlmsg_end(skb, nlh);
 
 	return 0;
@@ -3885,6 +3918,23 @@ static size_t if_nlmsg_stats_size(const struct net_device *dev,
 	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_OFFLOAD_XSTATS, 0))
 		size += rtnl_get_offload_stats_size(dev);
 
+	if (stats_attr_valid(filter_mask, IFLA_STATS_AF_SPEC, 0)) {
+		struct rtnl_af_ops *af_ops;
+
+		/* for IFLA_STATS_AF_SPEC */
+		size += nla_total_size(0);
+
+		list_for_each_entry(af_ops, &rtnl_af_ops, list) {
+			if (af_ops->get_stats_af_size) {
+				size += nla_total_size(
+					af_ops->get_stats_af_size(dev));
+
+				/* for AF_* */
+				size += nla_total_size(0);
+			}
+		}
+	}
+
 	return size;
 }
 

net/mpls/af_mpls.c

@@ -8,6 +8,7 @@
 #include <linux/ipv6.h>
 #include <linux/mpls.h>
 #include <linux/vmalloc.h>
+#include <linux/percpu.h>
 #include <net/ip.h>
 #include <net/dst.h>
 #include <net/sock.h>
@@ -17,8 +18,8 @@
 #include <net/netns/generic.h>
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6.h>
-#include <net/addrconf.h>
 #endif
+#include <net/addrconf.h>
 #include <net/nexthop.h>
 #include "internal.h"
 
@@ -48,11 +49,6 @@ static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
 	return rt;
 }
 
-static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
-{
-	return rcu_dereference_rtnl(dev->mpls_ptr);
-}
-
 bool mpls_output_possible(const struct net_device *dev)
 {
 	return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
@@ -98,6 +94,31 @@ bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 }
 EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
 
+void mpls_stats_inc_outucastpkts(struct net_device *dev,
+				 const struct sk_buff *skb)
+{
+	struct mpls_dev *mdev;
+
+	if (skb->protocol == htons(ETH_P_MPLS_UC)) {
+		mdev = mpls_dev_get(dev);
+		if (mdev)
+			MPLS_INC_STATS_LEN(mdev, skb->len,
+					   tx_packets,
+					   tx_bytes);
+	} else if (skb->protocol == htons(ETH_P_IP)) {
+		IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (skb->protocol == htons(ETH_P_IPV6)) {
+		struct inet6_dev *in6dev = __in6_dev_get(dev);
+
+		if (in6dev)
+			IP6_UPD_PO_STATS(dev_net(dev), in6dev,
+					 IPSTATS_MIB_OUT, skb->len);
+#endif
+	}
+}
+EXPORT_SYMBOL_GPL(mpls_stats_inc_outucastpkts);
+
 static u32 mpls_multipath_hash(struct mpls_route *rt,
 			       struct sk_buff *skb, bool bos)
 {
@@ -253,6 +274,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	struct mpls_nh *nh;
 	struct mpls_entry_decoded dec;
 	struct net_device *out_dev;
+	struct mpls_dev *out_mdev;
 	struct mpls_dev *mdev;
 	unsigned int hh_len;
 	unsigned int new_header_size;
@@ -262,17 +284,25 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	/* Careful this entire function runs inside of an rcu critical section */
 
 	mdev = mpls_dev_get(dev);
-	if (!mdev || !mdev->input_enabled)
+	if (!mdev)
 		goto drop;
 
-	if (skb->pkt_type != PACKET_HOST)
+	MPLS_INC_STATS_LEN(mdev, skb->len, rx_packets,
+			   rx_bytes);
+
+	if (!mdev->input_enabled) {
+		MPLS_INC_STATS(mdev, rx_dropped);
 		goto drop;
+	}
+
+	if (skb->pkt_type != PACKET_HOST)
+		goto err;
 
 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
-		goto drop;
+		goto err;
 
 	if (!pskb_may_pull(skb, sizeof(*hdr)))
-		goto drop;
+		goto err;
 
 	/* Read and decode the label */
 	hdr = mpls_hdr(skb);
@@ -285,33 +315,35 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	skb_orphan(skb);
 
 	rt = mpls_route_input_rcu(net, dec.label);
-	if (!rt)
+	if (!rt) {
+		MPLS_INC_STATS(mdev, rx_noroute);
 		goto drop;
+	}
 
 	nh = mpls_select_multipath(rt, skb, dec.bos);
 	if (!nh)
-		goto drop;
-
-	/* Find the output device */
-	out_dev = rcu_dereference(nh->nh_dev);
-	if (!mpls_output_possible(out_dev))
-		goto drop;
+		goto err;
 
 	if (skb_warn_if_lro(skb))
-		goto drop;
+		goto err;
 
 	skb_forward_csum(skb);
 
 	/* Verify ttl is valid */
 	if (dec.ttl <= 1)
-		goto drop;
+		goto err;
 	dec.ttl -= 1;
 
+	/* Find the output device */
+	out_dev = rcu_dereference(nh->nh_dev);
+	if (!mpls_output_possible(out_dev))
+		goto tx_err;
+
 	/* Verify the destination can hold the packet */
 	new_header_size = mpls_nh_header_size(nh);
 	mtu = mpls_dev_mtu(out_dev);
 	if (mpls_pkt_too_big(skb, mtu - new_header_size))
-		goto drop;
+		goto tx_err;
 
 	hh_len = LL_RESERVED_SPACE(out_dev);
 	if (!out_dev->header_ops)
@@ -319,7 +351,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 
 	/* Ensure there is enough space for the headers in the skb */
 	if (skb_cow(skb, hh_len + new_header_size))
-		goto drop;
+		goto tx_err;
 
 	skb->dev = out_dev;
 	skb->protocol = htons(ETH_P_MPLS_UC);
@@ -327,7 +359,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 	if (unlikely(!new_header_size && dec.bos)) {
 		/* Penultimate hop popping */
 		if (!mpls_egress(rt, skb, dec))
-			goto drop;
+			goto err;
 	} else {
 		bool bos;
 		int i;
@@ -343,6 +375,8 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 		}
 	}
 
+	mpls_stats_inc_outucastpkts(out_dev, skb);
+
 	/* If via wasn't specified then send out using device address */
 	if (nh->nh_via_table == MPLS_NEIGH_TABLE_UNSPEC)
 		err = neigh_xmit(NEIGH_LINK_TABLE, out_dev,
@@ -355,6 +389,13 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 				    __func__, err);
 	return 0;
 
+tx_err:
+	out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
+	if (out_mdev)
+		MPLS_INC_STATS(out_mdev, tx_errors);
+	goto drop;
+err:
+	MPLS_INC_STATS(mdev, rx_errors);
 drop:
 	kfree_skb(skb);
 	return NET_RX_DROP;
@@ -853,6 +894,70 @@ static int mpls_route_del(struct mpls_route_config *cfg)
 	return err;
 }
 
+static void mpls_get_stats(struct mpls_dev *mdev,
+			   struct mpls_link_stats *stats)
+{
+	struct mpls_pcpu_stats *p;
+	int i;
+
+	memset(stats, 0, sizeof(*stats));
+
+	for_each_possible_cpu(i) {
+		struct mpls_link_stats local;
+		unsigned int start;
+
+		p = per_cpu_ptr(mdev->stats, i);
+		do {
+			start = u64_stats_fetch_begin(&p->syncp);
+			local = p->stats;
+		} while (u64_stats_fetch_retry(&p->syncp, start));
+
+		stats->rx_packets	+= local.rx_packets;
+		stats->rx_bytes		+= local.rx_bytes;
+		stats->tx_packets	+= local.tx_packets;
+		stats->tx_bytes		+= local.tx_bytes;
+		stats->rx_errors	+= local.rx_errors;
+		stats->tx_errors	+= local.tx_errors;
+		stats->rx_dropped	+= local.rx_dropped;
+		stats->tx_dropped	+= local.tx_dropped;
+		stats->rx_noroute	+= local.rx_noroute;
+	}
+}
+
+static int mpls_fill_stats_af(struct sk_buff *skb,
+			      const struct net_device *dev)
+{
+	struct mpls_link_stats *stats;
+	struct mpls_dev *mdev;
+	struct nlattr *nla;
+
+	mdev = mpls_dev_get(dev);
+	if (!mdev)
+		return -ENODATA;
+
+	nla = nla_reserve_64bit(skb, MPLS_STATS_LINK,
+				sizeof(struct mpls_link_stats),
+				MPLS_STATS_UNSPEC);
+	if (!nla)
+		return -EMSGSIZE;
+
+	stats = nla_data(nla);
+	mpls_get_stats(mdev, stats);
+
+	return 0;
+}
+
+static size_t mpls_get_stats_af_size(const struct net_device *dev)
+{
+	struct mpls_dev *mdev;
+
+	mdev = mpls_dev_get(dev);
+	if (!mdev)
+		return 0;
+
+	return nla_total_size_64bit(sizeof(struct mpls_link_stats));
+}
+
 #define MPLS_PERDEV_SYSCTL_OFFSET(field)	\
 	(&((struct mpls_dev *)0)->field)
 
@@ -911,6 +1016,7 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev)
 {
 	struct mpls_dev *mdev;
 	int err = -ENOMEM;
+	int i;
 
 	ASSERT_RTNL();
 
@@ -918,6 +1024,17 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev)
 	if (!mdev)
 		return ERR_PTR(err);
 
+	mdev->stats = alloc_percpu(struct mpls_pcpu_stats);
+	if (!mdev->stats)
+		goto free;
+
+	for_each_possible_cpu(i) {
+		struct mpls_pcpu_stats *mpls_stats;
+
+		mpls_stats = per_cpu_ptr(mdev->stats, i);
+		u64_stats_init(&mpls_stats->syncp);
+	}
+
 	err = mpls_dev_sysctl_register(dev, mdev);
 	if (err)
 		goto free;
@@ -927,10 +1044,19 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev)
 	return mdev;
 
 free:
+	free_percpu(mdev->stats);
 	kfree(mdev);
 	return ERR_PTR(err);
 }
 
+static void mpls_dev_destroy_rcu(struct rcu_head *head)
+{
+	struct mpls_dev *mdev = container_of(head, struct mpls_dev, rcu);
+
+	free_percpu(mdev->stats);
+	kfree(mdev);
+}
+
 static void mpls_ifdown(struct net_device *dev, int event)
 {
 	struct mpls_route __rcu **platform_label;
@@ -1045,7 +1171,7 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
 		if (mdev) {
 			mpls_dev_sysctl_unregister(mdev);
 			RCU_INIT_POINTER(dev->mpls_ptr, NULL);
-			kfree_rcu(mdev, rcu);
+			call_rcu(&mdev->rcu, mpls_dev_destroy_rcu);
 		}
 		break;
 	case NETDEV_CHANGENAME:
@@ -1706,6 +1832,12 @@ static struct pernet_operations mpls_net_ops = {
 	.exit = mpls_net_exit,
 };
 
+static struct rtnl_af_ops mpls_af_ops __read_mostly = {
+	.family		   = AF_MPLS,
+	.fill_stats_af	   = mpls_fill_stats_af,
+	.get_stats_af_size = mpls_get_stats_af_size,
+};
+
 static int __init mpls_init(void)
 {
 	int err;
@@ -1722,6 +1854,8 @@ static int __init mpls_init(void)
 
 	dev_add_pack(&mpls_packet_type);
 
+	rtnl_af_register(&mpls_af_ops);
+
 	rtnl_register(PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, NULL);
 	rtnl_register(PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, NULL);
 	rtnl_register(PF_MPLS, RTM_GETROUTE, NULL, mpls_dump_routes, NULL);
@@ -1738,6 +1872,7 @@ module_init(mpls_init);
 static void __exit mpls_exit(void)
 {
 	rtnl_unregister_all(PF_MPLS);
+	rtnl_af_unregister(&mpls_af_ops);
 	dev_remove_pack(&mpls_packet_type);
 	unregister_netdevice_notifier(&mpls_dev_notifier);
 	unregister_pernet_subsys(&mpls_net_ops);

net/mpls/internal.h

@@ -9,13 +9,58 @@ struct mpls_entry_decoded {
 	u8 bos;
 };
 
+struct mpls_pcpu_stats {
+	struct mpls_link_stats	stats;
+	struct u64_stats_sync	syncp;
+};
+
 struct mpls_dev {
 	int				input_enabled;
 
+	struct mpls_pcpu_stats __percpu	*stats;
+
 	struct ctl_table_header		*sysctl;
 	struct rcu_head			rcu;
 };
 
+#if BITS_PER_LONG == 32
+
+#define MPLS_INC_STATS_LEN(mdev, len, pkts_field, bytes_field)		\
+	do {								\
+		__typeof__(*(mdev)->stats) *ptr =			\
+			raw_cpu_ptr((mdev)->stats);			\
+		local_bh_disable();					\
+		u64_stats_update_begin(&ptr->syncp);			\
+		ptr->stats.pkts_field++;				\
+		ptr->stats.bytes_field += (len);			\
+		u64_stats_update_end(&ptr->syncp);			\
+		local_bh_enable();					\
+	} while (0)
+
+#define MPLS_INC_STATS(mdev, field)					\
+	do {								\
+		__typeof__(*(mdev)->stats) *ptr =			\
+			raw_cpu_ptr((mdev)->stats);			\
+		local_bh_disable();					\
+		u64_stats_update_begin(&ptr->syncp);			\
+		ptr->stats.field++;					\
+		u64_stats_update_end(&ptr->syncp);			\
+		local_bh_enable();					\
+	} while (0)
+
+#else
+
+#define MPLS_INC_STATS_LEN(mdev, len, pkts_field, bytes_field)		\
+	do {								\
+		this_cpu_inc((mdev)->stats->stats.pkts_field);		\
+		this_cpu_add((mdev)->stats->stats.bytes_field, (len));	\
+	} while (0)
+
+#define MPLS_INC_STATS(mdev, field)			\
+	this_cpu_inc((mdev)->stats->stats.field)
+
+#endif
+
 struct sk_buff;
 
 #define LABEL_NOT_SPECIFIED (1 << 20)
@@ -114,6 +159,11 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *
 	return result;
 }
 
+static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
+{
+	return rcu_dereference_rtnl(dev->mpls_ptr);
+}
+
 int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
 		   const u32 label[]);
 int nla_get_labels(const struct nlattr *nla, u32 max_labels, u8 *labels,
@@ -123,5 +173,7 @@ int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
 bool mpls_output_possible(const struct net_device *dev);
 unsigned int mpls_dev_mtu(const struct net_device *dev);
 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
+void mpls_stats_inc_outucastpkts(struct net_device *dev,
+				 const struct sk_buff *skb);
 
 #endif /* MPLS_INTERNAL_H */

net/mpls/mpls_iptunnel.c

@@ -48,11 +48,15 @@ static int mpls_xmit(struct sk_buff *skb)
 	struct dst_entry *dst = skb_dst(skb);
 	struct rtable *rt = NULL;
 	struct rt6_info *rt6 = NULL;
+	struct mpls_dev *out_mdev;
 	int err = 0;
 	bool bos;
 	int i;
 	unsigned int ttl;
 
+	/* Find the output device */
+	out_dev = dst->dev;
+
 	/* Obtain the ttl */
 	if (dst->ops->family == AF_INET) {
 		ttl = ip_hdr(skb)->ttl;
@@ -66,8 +70,6 @@ static int mpls_xmit(struct sk_buff *skb)
 
 	skb_orphan(skb);
 
-	/* Find the output device */
-	out_dev = dst->dev;
 	if (!mpls_output_possible(out_dev) ||
 	    !dst->lwtstate || skb_warn_if_lro(skb))
 		goto drop;
@@ -109,6 +111,8 @@ static int mpls_xmit(struct sk_buff *skb)
 		bos = false;
 	}
 
+	mpls_stats_inc_outucastpkts(out_dev, skb);
+
 	if (rt)
 		err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
 				 skb);
@@ -122,6 +126,9 @@ static int mpls_xmit(struct sk_buff *skb)
 	return LWTUNNEL_XMIT_DONE;
 
 drop:
+	out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
+	if (out_mdev)
+		MPLS_INC_STATS(out_mdev, tx_errors);
 	kfree_skb(skb);
 	return -EINVAL;
 }