commit cb75994ec311b2cd50e5205efdcc0696abd6675d
author Wang Chen <wangchen@cn.fujitsu.com> Mon Dec 03 22:33:28 2007 +1100
committer David S. Miller <davem@davemloft.net> Mon Jan 28 14:55:47 2008 -0800
tree eb0fbb65bfe1b896a55ce8b987d6f4f3f4357e98
parent 6859d49475d4f32abe640372117e4b687906e6b6

[UDP]: Defer InDataGrams increment until recvmsg() does checksum

Thanks dave, herbert, gerrit, andi and other people for your
discussion about this problem.

UdpInDatagrams can be confusing because it counts packets that
might be dropped later.
Move UdpInDatagrams into recvmsg() as allowed by the RFC.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/udplite.txt

diff --git a/Documentation/networking/udplite.txt b/Documentation/networking/udplite.txt
index b6409ca..3870f28 100644
--- a/Documentation/networking/udplite.txt
+++ b/Documentation/networking/udplite.txt
@@ -236,7 +236,7 @@
 
   This displays UDP-Lite statistics variables, whose meaning is as follows.
 
-   InDatagrams:     Total number of received datagrams.
+   InDatagrams:     The total number of datagrams delivered to users.
 
    NoPorts:         Number of packets received to an unknown port.
                     These cases are counted separately (not as InErrors).

net/ipv4/udp.c

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 03c400c..3465d4a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -873,6 +873,8 @@
 	if (err)
 		goto out_free;
 
+	UDP_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
+
 	sock_recv_timestamp(msg, sk, skb);
 
 	/* Copy the address. */
@@ -966,10 +968,8 @@
 			int ret;
 
 			ret = (*up->encap_rcv)(sk, skb);
-			if (ret <= 0) {
-				UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);
+			if (ret <= 0)
 				return -ret;
-			}
 		}
 
 		/* FALLTHROUGH -- it's a UDP Packet */
@@ -1023,7 +1023,6 @@
 		goto drop;
 	}
 
-	UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);
 	return 0;
 
 drop:

net/ipv6/udp.c

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ee1cc3f..b0474a6 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -164,6 +164,8 @@
 	if (err)
 		goto out_free;
 
+	UDP6_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
+
 	sock_recv_timestamp(msg, sk, skb);
 
 	/* Copy the address. */
@@ -292,7 +294,7 @@
 			UDP6_INC_STATS_BH(UDP_MIB_RCVBUFERRORS, up->pcflag);
 		goto drop;
 	}
-	UDP6_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag);
+
 	return 0;
 drop:
 	UDP6_INC_STATS_BH(UDP_MIB_INERRORS, up->pcflag);