[DCCP]: Implement the CLOSING timer

So that we retransmit CLOSE/CLOSEREQ packets till they elicit an
answer or we hit a timeout.

Most of the machinery uses TCP approaches, this code has to be
polished & audited, but this is better than we had before.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 33968a9..53994f1 100644 (file)
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -255,7 +255,7 @@ extern int     dccp_v4_checksum(const struct sk_buff *skb,
 
 extern int        dccp_v4_send_reset(struct sock *sk,
                                      enum dccp_reset_codes code);
-extern void       dccp_send_close(struct sock *sk);
+extern void       dccp_send_close(struct sock *sk, const int active);
 
 struct dccp_skb_cb {
        __u8 dccpd_type;

diff --git a/net/dccp/input.c b/net/dccp/input.c
index 8540253..02af05e 100644 (file)
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -31,14 +31,9 @@ static void dccp_fin(struct sock *sk, struct sk_buff *skb)
 
 static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
 {
-       switch (sk->sk_state) {
-       case DCCP_PARTOPEN:
-       case DCCP_OPEN:
-               dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
-               dccp_fin(sk, skb);
-               dccp_set_state(sk, DCCP_CLOSED);
-               break;
-       }
+       dccp_v4_send_reset(sk, DCCP_RESET_CODE_CLOSED);
+       dccp_fin(sk, skb);
+       dccp_set_state(sk, DCCP_CLOSED);
 }
 
 static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
@@ -54,13 +49,8 @@ static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
                return;
        }
 
-       switch (sk->sk_state) {
-       case DCCP_PARTOPEN:
-       case DCCP_OPEN:
-               dccp_set_state(sk, DCCP_CLOSING);
-               dccp_send_close(sk);
-               break;
-       }
+       dccp_set_state(sk, DCCP_CLOSING);
+       dccp_send_close(sk, 0);
 }
 
 static inline void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
@@ -562,6 +552,12 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
                               DCCP_PKT_SYNC);
                goto discard;
+       } else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
+               dccp_rcv_closereq(sk, skb);
+               goto discard;
+       } else if (dh->dccph_type == DCCP_PKT_CLOSE) {
+               dccp_rcv_close(sk, skb);
+               return 0;
        }
 
        switch (sk->sk_state) {

diff --git a/net/dccp/output.c b/net/dccp/output.c
index 708fc3c..630ca77 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -96,8 +96,7 @@ int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                dh->dccph_checksum = dccp_v4_checksum(skb, inet->saddr,
                                                      inet->daddr);
 
-               if (dcb->dccpd_type == DCCP_PKT_ACK ||
-                   dcb->dccpd_type == DCCP_PKT_DATAACK)
+               if (set_ack)
                        dccp_event_ack_sent(sk);
 
                DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
@@ -429,18 +428,15 @@ void dccp_send_sync(struct sock *sk, const u64 seq,
  * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
  * any circumstances.
  */
-void dccp_send_close(struct sock *sk)
+void dccp_send_close(struct sock *sk, const int active)
 {
        struct dccp_sock *dp = dccp_sk(sk);
        struct sk_buff *skb;
+       const unsigned int prio = active ? GFP_KERNEL : GFP_ATOMIC;
 
-       /* Socket is locked, keep trying until memory is available. */
-       for (;;) {
-               skb = alloc_skb(sk->sk_prot->max_header, GFP_KERNEL);
-               if (skb != NULL)
-                       break;
-               yield();
-       }
+       skb = alloc_skb(sk->sk_prot->max_header, prio);
+       if (skb == NULL)
+               return;
 
        /* Reserve space for headers and prepare control bits. */
        skb_reserve(skb, sk->sk_prot->max_header);
@@ -449,7 +445,12 @@ void dccp_send_close(struct sock *sk)
                                        DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
 
        skb_set_owner_w(skb, sk);
-       dccp_transmit_skb(sk, skb);
+       if (active) {
+               BUG_TRAP(sk->sk_send_head == NULL);
+               sk->sk_send_head = skb;
+               dccp_transmit_skb(sk, skb_clone(skb, prio));
+       } else
+               dccp_transmit_skb(sk, skb);
 
        ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
        ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 8b613c3..a3f8a80 100644 (file)
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -402,12 +402,15 @@ void dccp_close(struct sock *sk, long timeout)
                /* Check zero linger _after_ checking for unread data. */
                sk->sk_prot->disconnect(sk, 0);
        } else if (dccp_close_state(sk)) {
-               dccp_send_close(sk);
+               dccp_send_close(sk, 1);
        }
 
        sk_stream_wait_close(sk, timeout);
 
 adjudge_to_death:
+       /*
+        * It is the last release_sock in its life. It will remove backlog.
+        */
        release_sock(sk);
        /*
         * Now socket is owned by kernel and we acquire BH lock
@@ -419,11 +422,26 @@ adjudge_to_death:
 
        sock_hold(sk);
        sock_orphan(sk);
-                                               
-       if (sk->sk_state != DCCP_CLOSED)
+
+       /*
+        * The last release_sock may have processed the CLOSE or RESET
+        * packet moving sock to CLOSED state, if not we have to fire
+        * the CLOSE/CLOSEREQ retransmission timer, see "8.3. Termination"
+        * in draft-ietf-dccp-spec-11. -acme
+        */
+       if (sk->sk_state == DCCP_CLOSING) {
+               /* FIXME: should start at 2 * RTT */
+               /* Timer for repeating the CLOSE/CLOSEREQ until an answer. */
+               inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                         inet_csk(sk)->icsk_rto,
+                                         DCCP_RTO_MAX);
+#if 0
+               /* Yeah, we should use sk->sk_prot->orphan_count, etc */
                dccp_set_state(sk, DCCP_CLOSED);
+#endif
+       }
 
-       atomic_inc(&dccp_orphan_count);
+       atomic_inc(sk->sk_prot->orphan_count);
        if (sk->sk_state == DCCP_CLOSED)
                inet_csk_destroy_sock(sk);