4 files changed, 40 insertions, 20 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 17b3f70fbbc3..c618fbf7d173 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -288,6 +288,7 @@ struct sk_buff {
         __u8                    pkt_type:3,
                                 fclone:2,
                                 ipvs_property:1,
+                                peeked:1,
                                 nf_trace:1;
         __be16                  protocol;
 
@@ -1538,6 +1539,8 @@ static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
                      skb = skb->prev)
 
 
+extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
+                                           int *peeked, int *err);
 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
                                          int noblock, int *err);
 extern unsigned int    datagram_poll(struct file *file, struct socket *sock,
diff --git a/net/core/datagram.c b/net/core/datagram.c
index fbd6c76436d0..2d733131d7ce 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -115,10 +115,10 @@ out_noerr:
 }
 
 /**
- *      skb_recv_datagram - Receive a datagram skbuff
+ *      __skb_recv_datagram - Receive a datagram skbuff
  *      @sk: socket
  *      @flags: MSG_ flags
- *      @noblock: blocking operation?
+ *      @peeked: returns non-zero if this packet has been seen before
  *      @err: error code returned
  *
  *      Get a datagram skbuff, understands the peeking, nonblocking wakeups
@@ -143,8 +143,8 @@ out_noerr:
  *      quite explicitly by POSIX 1003.1g, don't change them without having
  *      the standard around please.
  */
-struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
-                                  int noblock, int *err)
+struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
+                                    int *peeked, int *err)
 {
         struct sk_buff *skb;
         long timeo;
@@ -156,7 +156,7 @@ struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
         if (error)
                 goto no_packet;
 
-        timeo = sock_rcvtimeo(sk, noblock);
+        timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 
         do {
                 /* Again only user level code calls this function, so nothing
@@ -165,18 +165,19 @@ struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
                  * Look at current nfs client by the way...
                  * However, this function was corrent in any case. 8)
                  */
-                if (flags & MSG_PEEK) {
-                        unsigned long cpu_flags;
-
-                        spin_lock_irqsave(&sk->sk_receive_queue.lock,
-                                          cpu_flags);
-                        skb = skb_peek(&sk->sk_receive_queue);
-                        if (skb)
+                unsigned long cpu_flags;
+
+                spin_lock_irqsave(&sk->sk_receive_queue.lock, cpu_flags);
+                skb = skb_peek(&sk->sk_receive_queue);
+                if (skb) {
+                        *peeked = skb->peeked;
+                        if (flags & MSG_PEEK) {
+                                skb->peeked = 1;
                                 atomic_inc(&skb->users);
-                        spin_unlock_irqrestore(&sk->sk_receive_queue.lock,
-                                               cpu_flags);
-                } else
-                        skb = skb_dequeue(&sk->sk_receive_queue);
+                        } else
+                                __skb_unlink(skb, &sk->sk_receive_queue);
+                }
+                spin_unlock_irqrestore(&sk->sk_receive_queue.lock, cpu_flags);
 
                 if (skb)
                         return skb;
@@ -194,6 +195,16 @@ no_packet:
         *err = error;
         return NULL;
 }
+EXPORT_SYMBOL(__skb_recv_datagram);
+
+struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
+                                  int noblock, int *err)
+{
+        int peeked;
+
+        return __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
+                                   &peeked, err);
+}
 
 void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
 {
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 78cfcb4a1b3f..9ed6393c65d9 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -827,6 +827,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
         struct sk_buff *skb;
         unsigned int ulen, copied;
+        int peeked;
         int err;
         int is_udplite = IS_UDPLITE(sk);
 
@@ -840,7 +841,8 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                 return ip_recv_error(sk, msg, len);
 
 try_again:
-        skb = skb_recv_datagram(sk, flags, noblock, &err);
+        skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
+                                  &peeked, &err);
         if (!skb)
                 goto out;
 
@@ -875,7 +877,8 @@ try_again:
         if (err)
                 goto out_free;
 
-        UDP_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
+        if (!peeked)
+                UDP_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
 
         sock_recv_timestamp(msg, sk, skb);
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 36bdcd2e1b52..fa640765385e 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -123,6 +123,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
         struct inet_sock *inet = inet_sk(sk);
         struct sk_buff *skb;
         unsigned int ulen, copied;
+        int peeked;
         int err;
         int is_udplite = IS_UDPLITE(sk);
 
@@ -133,7 +134,8 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
                 return ipv6_recv_error(sk, msg, len);
 
 try_again:
-        skb = skb_recv_datagram(sk, flags, noblock, &err);
+        skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
+                                  &peeked, &err);
         if (!skb)
                 goto out;
 
@@ -166,7 +168,8 @@ try_again:
         if (err)
                 goto out_free;
 
-        UDP6_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
+        if (!peeked)
+                UDP6_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
 
         sock_recv_timestamp(msg, sk, skb);