From: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Date: Wed, 10 Feb 2010 20:26:18 +0000 (+0000)
Subject: dccp: support for passing MSG_TRUNC
X-Git-Tag: upstream/snapshot3+hdmi~15536^2~341
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=55d955902a7f78e3e7c9ddbc71a4a050d9d44810;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

dccp: support for passing MSG_TRUNC

DCCP is datagram-oriented but lacks UDP's support for MSG_TRUNC as defined in
recvmsg(2)/recv(2). Hence the following 'Hello world\0' receiver

  len = recv(fd, buf, 10, MSG_PEEK | MSG_TRUNC);

wrongly (always) returns 10, while in UDP it returns 12 as expected.
This patch adds the missing MSG_TRUNC support to recvmsg().

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 671cd14..85ec1cb 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -835,6 +835,8 @@ verify_sock_status:
 			len = -EFAULT;
 			break;
 		}
+		if (flags & MSG_TRUNC)
+			len = skb->len;
 	found_fin_ok:
 		if (!(flags & MSG_PEEK))
 			sk_eat_skb(sk, skb, 0);