[DCCP]: Perform SHUT_RD and SHUT_WR on receiving close

The first change is to close the write-end in addition to the read-end when
a fin-like segment (Close or CloseReq) is received by DCCP. This accounts
for the fact that DCCP, in contrast to TCP, does not have a half-close. I
checked the specification - when a fin-like segment has been sent there is
no guarantee at all that any further data will be processed.

Thus this patch performs SHUT_WR in addition to the SHUT_RD when a fin-like
segment is encountered.

The second change is minor; I noted that code appears twice in different
places and think it makes sense to put this into a self-contained function.

Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
 net/dccp/input.c |   22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -19,16 +19,27 @@
 #include "ccid.h"
 #include "dccp.h"
 
-static void dccp_fin(struct sock *sk, struct sk_buff *skb)
+static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
 {
-       sk->sk_shutdown |= RCV_SHUTDOWN;
-       sock_set_flag(sk, SOCK_DONE);
        __skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
        __skb_queue_tail(&sk->sk_receive_queue, skb);
        skb_set_owner_r(skb, sk);
        sk->sk_data_ready(sk, 0);
 }
 
+static void dccp_fin(struct sock *sk, struct sk_buff *skb)
+{
+       /*
+        * On receiving Close/CloseReq, both RD/WR shutdown are performed.
+        * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after
+        * receiving the closing segment, but there is no guarantee that such
+        * data will be processed at all.
+        */
+       sk->sk_shutdown = SHUTDOWN_MASK;
+       sock_set_flag(sk, SOCK_DONE);
+       dccp_enqueue_skb(sk, skb);
+}
+
 static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
 {
        if (sk->sk_state == DCCP_CLOSEREQ) {
@@ -187,10 +198,7 @@ static int __dccp_rcv_established(struct
                 * FIXME: check if sk_receive_queue is full, schedule 
DATA_DROPPED
                 * option if it is.
                 */
-               __skb_pull(skb, dh->dccph_doff * 4);
-               __skb_queue_tail(&sk->sk_receive_queue, skb);
-               skb_set_owner_r(skb, sk);
-               sk->sk_data_ready(sk, 0);
+               dccp_enqueue_skb(sk, skb);
                return 0;
        case DCCP_PKT_ACK:
                goto discard;
-
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