packet_diag: disclose meminfo values

sk_rmem_alloc is disclosed via /proc/net/packet but not via netlink messages.
The goal is to have the same level of information.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/packet_diag.h

@@ -16,6 +16,7 @@ struct packet_diag_req {
 #define PACKET_SHOW_MCLIST	0x00000002 /* A set of packet_diag_mclist-s */
 #define PACKET_SHOW_RING_CFG	0x00000004 /* Rings configuration parameters */
 #define PACKET_SHOW_FANOUT	0x00000008
+#define PACKET_SHOW_MEMINFO	0x00000010
 
 struct packet_diag_msg {
 	__u8	pdiag_family;
@@ -33,6 +34,7 @@ enum {
 	PACKET_DIAG_TX_RING,
 	PACKET_DIAG_FANOUT,
 	PACKET_DIAG_UID,
+	PACKET_DIAG_MEMINFO,
 
 	__PACKET_DIAG_MAX,
 };

net/packet/diag.c

@@ -166,6 +166,10 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
 			pdiag_put_fanout(po, skb))
 		goto out_nlmsg_trim;
 
+	if ((req->pdiag_show & PACKET_SHOW_MEMINFO) &&
+	    sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
+		goto out_nlmsg_trim;
+
 	return nlmsg_end(skb, nlh);
 
 out_nlmsg_trim: