[NETLINK]: Mirror UDP MSG_TRUNC semantics.

If the user passes MSG_TRUNC in via msg_flags, return
the full packet size not the truncated size.

Idea from Herbert Xu and Thomas Graf.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index c48b0f49f00362d1ec7ed5625a1ab8e6d73bf946..5890210d77301eeb49d308fe6cf472965d3be7c0 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1242,6 +1242,9 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
 
        scm_recv(sock, msg, siocb->scm, flags);
 
+       if (flags & MSG_TRUNC)
+               copied = skb->len;
+
 out:
        netlink_rcv_wake(sk);
        return err ? : copied;