psample: Add additional metadata attributes

Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a 64-bit value
* End-to-end latency of the packet in nanoseconds resolution
* Software timestamp in nanoseconds resolution (always available)
* Packet's protocol. Needed for packet dissection in user space (always
available)

Signed-off-by: Ido Schimmel <[e-mail]>
Reviewed-by: Jiri Pirko <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/psample.h

···
 	u32 trunc_size;
 	int in_ifindex;
 	int out_ifindex;
+	u16 out_tc;
+	u64 out_tc_occ;	/* bytes */
+	u64 latency;	/* nanoseconds */
+	u8 out_tc_valid:1,
+	   out_tc_occ_valid:1,
+	   latency_valid:1,
+	   unused:5;
 };
 
 struct psample_group *psample_group_get(struct net *net, u32 group_num);

include/uapi/linux/psample.h

···
 	/* commands attributes */
 	PSAMPLE_ATTR_GROUP_REFCOUNT,
 
+	PSAMPLE_ATTR_PAD,
+	PSAMPLE_ATTR_OUT_TC,		/* u16 */
+	PSAMPLE_ATTR_OUT_TC_OCC,	/* u64, bytes */
+	PSAMPLE_ATTR_LATENCY,		/* u64, nanoseconds */
+	PSAMPLE_ATTR_TIMESTAMP,		/* u64, nanoseconds */
+	PSAMPLE_ATTR_PROTO,		/* u16 */
+
 	__PSAMPLE_ATTR_MAX
 };
 

net/psample/psample.c

···
 #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>
···
 void psample_sample_packet(struct psample_group *group, 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;
···
 
 	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(sizeof(u32)) +	/* seq */
+		   nla_total_size_64bit(sizeof(u64)) +	/* timestamp */
+		   nla_total_size(sizeof(u16));		/* protocol */
 
 #ifdef CONFIG_INET
 	tun_info = skb_tunnel_info(skb);
···
 		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;