sock: introduce SO_MEMINFO getsockopt

Allows reading of SK_MEMINFO_VARS via socket option. This way an
application can get all meminfo related information in single socket
option call instead of multiple calls.

Adds helper function, sk_get_meminfo(), and uses that for both
getsockopt and sock_diag_put_meminfo().

Suggested by Eric Dumazet.

Signed-off-by: Josh Hunt <johunt@akamai.com>
Reviewed-by: Jason Baron <jbaron@akamai.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 31 insertions, 9 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index a83731c..f8c0373 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1313,6 +1313,21 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sk->sk_incoming_cpu;
 		break;
 
+	case SO_MEMINFO:
+	{
+		u32 meminfo[SK_MEMINFO_VARS];
+
+		if (get_user(len, optlen))
+			return -EFAULT;
+
+		sk_get_meminfo(sk, meminfo);
+
+		len = min_t(unsigned int, len, sizeof(meminfo));
+		if (copy_to_user(optval, &meminfo, len))
+			return -EFAULT;
+
+		goto lenout;
+	}
 	default:
 		/* We implement the SO_SNDLOWAT etc to not be settable
 		 * (1003.1g 7).
@@ -2861,6 +2876,21 @@ void sk_common_release(struct sock *sk)
 }
 EXPORT_SYMBOL(sk_common_release);
 
+void sk_get_meminfo(const struct sock *sk, u32 *mem)
+{
+	memset(mem, 0, sizeof(*mem) * SK_MEMINFO_VARS);
+
+	mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
+	mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
+	mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
+	mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
+	mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
+	mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
+	mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
+	mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len;
+	mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops);
+}
+
 #ifdef CONFIG_PROC_FS
 #define PROTO_INUSE_NR	64	/* should be enough for the first time */
 struct prot_inuse {
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 6b10573..8d11ee7 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -59,15 +59,7 @@ int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
 {
 	u32 mem[SK_MEMINFO_VARS];
 
-	mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
-	mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
-	mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
-	mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
-	mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
-	mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
-	mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
-	mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len;
-	mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops);
+	sk_get_meminfo(sk, mem);
 
 	return nla_put(skb, attrtype, sizeof(mem), &mem);
 }