[PATCH net] inet_diag: add cgroup id attribute

[Dmitry Yakunin <zeil@yandex-team.ru>]

This patch adds cgroup v2 id to common inet diag message attributes.
This allows investigate sockets on per cgroup basis when
net_cls/net_prio cgroup not used.

Signed-off-by: Dmitry Yakunin <zeil@yandex-team.ru>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 include/linux/inet_diag.h      | 6 +++++-
 include/uapi/linux/inet_diag.h | 1 +
 net/ipv4/inet_diag.c           | 7 +++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
index c91cf2d..8bc5e7d 100644
--- a/include/linux/inet_diag.h
+++ b/include/linux/inet_diag.h
@@ -66,7 +66,11 @@ static inline size_t inet_diag_msg_attrs_size(void)
 		+ nla_total_size(1)  /* INET_DIAG_SKV6ONLY */
 #endif
 		+ nla_total_size(4)  /* INET_DIAG_MARK */
-		+ nla_total_size(4); /* INET_DIAG_CLASS_ID */
+		+ nla_total_size(4)  /* INET_DIAG_CLASS_ID */
+#ifdef CONFIG_CGROUPS
+		+ nla_total_size(8)  /* INET_DIAG_CGROUP_ID */
+#endif
+		;
 }
 int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
 			     struct inet_diag_msg *r, int ext,
diff --git a/include/uapi/linux/inet_diag.h b/include/uapi/linux/inet_diag.h
index a1ff345..dc87ad6 100644
--- a/include/uapi/linux/inet_diag.h
+++ b/include/uapi/linux/inet_diag.h
@@ -154,6 +154,7 @@ enum {
 	INET_DIAG_CLASS_ID,	/* request as INET_DIAG_TCLASS */
 	INET_DIAG_MD5SIG,
 	INET_DIAG_ULP_INFO,
+	INET_DIAG_CGROUP_ID,
 	__INET_DIAG_MAX,
 };
 
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 8c83775..ba0bb14 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -161,6 +161,13 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
 			goto errout;
 	}
 
+#ifdef CONFIG_CGROUPS
+	if (nla_put_u64_64bit(skb, INET_DIAG_CGROUP_ID,
+			      cgroup_id(sock_cgroup_ptr(&sk->sk_cgrp_data)),
+			      INET_DIAG_PAD))
+		goto errout;
+#endif
+
 	r->idiag_uid = from_kuid_munged(user_ns, sock_i_uid(sk));
 	r->idiag_inode = sock_i_ino(sk);
 
-- 
2.7.4