udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet
authorXufeng Zhang <xufeng.zhang@windriver.com>
Tue, 21 Jun 2011 10:43:40 +0000 (10:43 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 22 Jun 2011 05:34:27 +0000 (22:34 -0700)
commit9cfaa8def1c795a512bc04f2aec333b03724ca2e
tree2c4bff0afe8424472b780a65a8d356db2d62caf4
parent32c90254ed4a0c698caa0794ebb4de63fcc69631
udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet

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@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/udp.c
net/ipv6/udp.c