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Commit f26ba175 authored by Wei Yongjun's avatar Wei Yongjun Committed by David S. Miller
Browse files

udp: Fix the SNMP counter of UDP_MIB_INDATAGRAMS 



If UDP echo is sent to xinetd/echo-dgram, the UDP reply will be received
at the sender. But the SNMP counter of UDP_MIB_INDATAGRAMS will be not
increased, UDP6_MIB_INDATAGRAMS will be increased instead.

  Endpoint A                      Endpoint B
  UDP Echo request ----------->
  (IPv4, Dst port=7)
                   <----------    UDP Echo Reply
                                  (IPv4, Src port=7)

This bug is come from this patch cb75994e.

It do counter UDP[6]_MIB_INDATAGRAMS until udp[v6]_recvmsg. Because
xinetd used IPv6 socket to receive UDP messages, thus, when received
UDP packet, the UDP6_MIB_INDATAGRAMS will be increased in function
udpv6_recvmsg() even if the packet is a IPv4 UDP packet.

This patch fixed the problem.

Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 70d9d158

net/ipv6/udp.c

+13 −5
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
	int peeked;

	int err;

	int is_udplite = IS_UDPLITE(sk);

	int is_udp4;



	if (addr_len)

		*addr_len=sizeof(struct sockaddr_in6);
@@ -158,6 +159,8 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
	else if (copied < ulen)

		msg->msg_flags |= MSG_TRUNC;



	is_udp4 = (skb->protocol == htons(ETH_P_IP));



	/*

	 * If checksum is needed at all, try to do it while copying the

	 * data.  If the data is truncated, or if we only want a partial
@@ -180,9 +183,14 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
	if (err)

		goto out_free;



	if (!peeked)

	if (!peeked) {

		if (is_udp4)

			UDP_INC_STATS_USER(sock_net(sk),

					UDP_MIB_INDATAGRAMS, is_udplite);

		else

			UDP6_INC_STATS_USER(sock_net(sk),

					UDP_MIB_INDATAGRAMS, is_udplite);

	}



	sock_recv_timestamp(msg, sk, skb);
@@ -196,7 +204,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
		sin6->sin6_flowinfo = 0;

		sin6->sin6_scope_id = 0;



		if (skb->protocol == htons(ETH_P_IP))

		if (is_udp4)

			ipv6_addr_set(&sin6->sin6_addr, 0, 0,

				      htonl(0xffff), ip_hdr(skb)->saddr);

		else {
@@ -207,7 +215,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
		}



	}

	if (skb->protocol == htons(ETH_P_IP)) {

	if (is_udp4) {

		if (inet->cmsg_flags)

			ip_cmsg_recv(msg, skb);

	} else {