[PATCH net-next 3/8] net: psample: add user cookie

[Adrian Moreno <amorenoz@redhat.com>]

Add a user cookie to the sample metadata so that sample emitters can
provide more contextual information to samples.

If present, send the user cookie in a new attribute:
PSAMPLE_ATTR_USER_COOKIE.

Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
---
 include/net/psample.h        |  2 ++
 include/uapi/linux/psample.h |  1 +
 net/psample/psample.c        | 12 +++++++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/net/psample.h b/include/net/psample.h
index 0509d2d6be67..2ac71260a546 100644
--- a/include/net/psample.h
+++ b/include/net/psample.h
@@ -25,6 +25,8 @@ struct psample_metadata {
 	   out_tc_occ_valid:1,
 	   latency_valid:1,
 	   unused:5;
+	const u8 *user_cookie;
+	u32 user_cookie_len;
 };
 
 struct psample_group *psample_group_get(struct net *net, u32 group_num);
diff --git a/include/uapi/linux/psample.h b/include/uapi/linux/psample.h
index 9d62983af0a4..83dc919c4023 100644
--- a/include/uapi/linux/psample.h
+++ b/include/uapi/linux/psample.h
@@ -19,6 +19,7 @@ enum {
 	PSAMPLE_ATTR_LATENCY,		/* u64, nanoseconds */
 	PSAMPLE_ATTR_TIMESTAMP,		/* u64, nanoseconds */
 	PSAMPLE_ATTR_PROTO,		/* u16 */
+	PSAMPLE_ATTR_USER_COOKIE,	/* binary, user provided data */
 
 	__PSAMPLE_ATTR_MAX
 };
diff --git a/net/psample/psample.c b/net/psample/psample.c
index f5f77515b969..476aaad7a885 100644
--- a/net/psample/psample.c
+++ b/net/psample/psample.c
@@ -480,7 +480,8 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
 		   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 */
+		   nla_total_size(sizeof(u16)) +	/* protocol */
+		   nla_total_size(md->user_cookie_len);	/* user_cookie */
 
 #ifdef CONFIG_INET
 	tun_info = skb_tunnel_info(skb);
@@ -579,6 +580,15 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
 			goto error;
 	}
 #endif
+	if (md->user_cookie && md->user_cookie_len) {
+		int nla_len = nla_total_size(md->user_cookie_len);
+		struct nlattr *nla;
+
+		nla = skb_put(nl_skb, nla_len);
+		nla->nla_type = PSAMPLE_ATTR_USER_COOKIE;
+		nla->nla_len = nla_attr_size(md->user_cookie_len);
+		memcpy(nla_data(nla), md->user_cookie, md->user_cookie_len);
+	}
 
 	genlmsg_end(nl_skb, data);
 	psample_nl_obj_desc_init(&desc, group->group_num);
-- 
2.44.0