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Message-Id: <1308689020-1873-4-git-send-email-paul.gortmaker@windriver.com>
Date: Tue, 21 Jun 2011 16:43:40 -0400
From: Paul Gortmaker <paul.gortmaker@...driver.com>
To: davem@...emloft.net, eric.dumazet@...il.com
Cc: netdev@...r.kernel.org, Xufeng Zhang <xufeng.zhang@...driver.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [PATCH net-next 3/3] udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet
From: Xufeng Zhang <xufeng.zhang@...driver.com>
Consider this scenario: When the size of the first received udp packet
is bigger than the receive buffer, MSG_TRUNC bit is set in msg->msg_flags.
However, if checksum error happens and this is a blocking socket, it will
goto try_again loop to receive the next packet. But if the size of the
next udp packet is smaller than receive buffer, MSG_TRUNC flag should not
be set, but because MSG_TRUNC bit is not cleared in msg->msg_flags before
receive the next packet, MSG_TRUNC is still set, which is wrong.
Fix this problem by clearing MSG_TRUNC flag when starting over for a
new packet.
Signed-off-by: Xufeng Zhang <xufeng.zhang@...driver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
net/ipv4/udp.c | 3 +++
net/ipv6/udp.c | 3 +++
2 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 6f53a5a..15d550c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1249,6 +1249,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1e7a43f..328985c 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -455,6 +455,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
--
1.7.4.4
--
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