Initial implementation of transmit buffering. Tested using netem with
delay and loss also.

Signed off by: Ian McDonald <[EMAIL PROTECTED]>
----
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 088529f..4a2f845 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -411,6 +411,8 @@ struct dccp_ackvec;
  * @dccps_role - Role of this sock, one of %dccp_role
  * @dccps_ndp_count - number of Non Data Packets since last data packet
  * @dccps_hc_rx_ackvec - rx half connection ack vector
+ * @dccps_xmit_timer - timer for when CCID is not ready to send
+ * @dccps_xmit_lock - lock for transmitting
  */
 struct dccp_sock {
        /* inet_connection_sock has to be the first member of dccp_sock */
@@ -443,6 +445,8 @@ struct dccp_sock {
        enum dccp_role                  dccps_role:2;
        __u8                            dccps_hc_rx_insert_options:1;
        __u8                            dccps_hc_tx_insert_options:1;
+       struct timer_list               dccps_xmit_timer;
+       spinlock_t                      dccps_xmit_lock;
 };

 static inline struct dccp_sock *dccp_sk(const struct sock *sk)
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 93f26dd..82431c0 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -5,7 +5,7 @@
  *
  *  An implementation of the DCCP protocol
  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[EMAIL PROTECTED]>
- *  Copyright (c) 2005 Ian McDonald <[EMAIL PROTECTED]>
+ *  Copyright (c) 2005-6 Ian McDonald <[EMAIL PROTECTED]>
  *
  *     This program is free software; you can redistribute it and/or modify it
  *     under the terms of the GNU General Public License version 2 as
@@ -126,7 +126,7 @@ extern void dccp_send_delayed_ack(struct
 extern void dccp_send_sync(struct sock *sk, const u64 seq,
                           const enum dccp_pkt_type pkt_type);

-extern int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo);
+void dccp_write_xmit(struct sock *sk, int block);
 extern void dccp_write_space(struct sock *sk);

 extern void dccp_init_xmit_timers(struct sock *sk);
diff --git a/net/dccp/output.c b/net/dccp/output.c
index efd7ffb..90b802d 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -2,7 +2,8 @@
  *  net/dccp/output.c
  *
  *  An implementation of the DCCP protocol
- *  Arnaldo Carvalho de Melo <[EMAIL PROTECTED]>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[EMAIL PROTECTED]>
+ *  Copyright (c) 2006 Ian McDonald <[EMAIL PROTECTED]>
  *
  *     This program is free software; you can redistribute it and/or
  *     modify it under the terms of the GNU General Public License
@@ -191,7 +192,7 @@ static int dccp_wait_for_ccid(struct soc
        while (1) {
                prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);

-               if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+               if (sk->sk_err)
                        goto do_error;
                if (!*timeo)
                        goto do_nonblock;
@@ -207,9 +208,11 @@ static int dccp_wait_for_ccid(struct soc
                        goto do_nonblock;

                sk->sk_write_pending++;
+               spin_unlock(&dp->dccps_xmit_lock);
                release_sock(sk);
                *timeo -= schedule_timeout(delay);
                lock_sock(sk);
+               spin_lock(&dp->dccps_xmit_lock);
                sk->sk_write_pending--;
        }
 out:
@@ -227,37 +230,56 @@ do_interrupted:
        goto out;
 }

-int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
-{
-       const struct dccp_sock *dp = dccp_sk(sk);
-       int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
-                                        skb->len);
+static void dccp_write_xmit_timer(unsigned long sk) {
+       dccp_write_xmit((struct sock *)sk,0);
+}

-       if (err > 0)
-               err = dccp_wait_for_ccid(sk, skb, timeo);
+void dccp_write_xmit(struct sock *sk, int block)
+{
+       struct dccp_sock *dp = dccp_sk(sk);
+       struct sk_buff *skb;
+       long timeo = 2000; /* FIXME imcdnzl - 2 second default */

-       if (err == 0) {
-               struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
-               const int len = skb->len;
+       spin_lock(&dp->dccps_xmit_lock);
+       
+       while ((skb = skb_peek(&sk->sk_write_queue))) {
+               int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+                                        skb->len);
+               
+               if (err > 0) {
+                       if (likely(!block)) {
+                               mod_timer(&dp->dccps_xmit_timer,
+                                               msecs_to_jiffies(err)+jiffies);
+                               goto xmit_out;
+                       } else {
+                               err = dccp_wait_for_ccid(sk, skb, &timeo);
+                       }
+               }

-               if (sk->sk_state == DCCP_PARTOPEN) {
-                       /* See 8.1.5.  Handshake Completion */
-                       inet_csk_schedule_ack(sk);
-                       inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
+               skb_dequeue(&sk->sk_write_queue);
+               if (err == 0) {
+                       struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+                       const int len = skb->len;
+
+                       if (sk->sk_state == DCCP_PARTOPEN) {
+                               /* See 8.1.5.  Handshake Completion */
+                               inet_csk_schedule_ack(sk);
+                               inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
                                                  inet_csk(sk)->icsk_rto,
                                                  DCCP_RTO_MAX);
-                       dcb->dccpd_type = DCCP_PKT_DATAACK;
-               } else if (dccp_ack_pending(sk))
-                       dcb->dccpd_type = DCCP_PKT_DATAACK;
-               else
-                       dcb->dccpd_type = DCCP_PKT_DATA;
-
-               err = dccp_transmit_skb(sk, skb);
-               ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
-       } else
-               kfree_skb(skb);
-
-       return err;
+                               dcb->dccpd_type = DCCP_PKT_DATAACK;
+                       } else if (dccp_ack_pending(sk))
+                               dcb->dccpd_type = DCCP_PKT_DATAACK;
+                       else
+                               dcb->dccpd_type = DCCP_PKT_DATA;
+
+                       err = dccp_transmit_skb(sk, skb);
+                       ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, 
len);
+               } else
+                       kfree(skb);
+       }
+xmit_out:
+       spin_unlock(&dp->dccps_xmit_lock);
 }

 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
@@ -396,6 +418,10 @@ static inline void dccp_connect_init(str
        dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));

        icsk->icsk_retransmits = 0;
+       init_timer(&dp->dccps_xmit_timer);
+       dp->dccps_xmit_timer.data = (unsigned long)sk;
+       dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
+       dp->dccps_xmit_lock = SPIN_LOCK_UNLOCKED;
 }

 int dccp_connect(struct sock *sk)
@@ -527,8 +553,11 @@ void dccp_send_close(struct sock *sk, co
                                        DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;

        if (active) {
+               dccp_write_xmit(sk, 1);
                dccp_skb_entail(sk, skb);
                dccp_transmit_skb(sk, skb_clone(skb, prio));
-       } else
+               /* FIXME do we need a retransmit timer here? */
+       } else {
                dccp_transmit_skb(sk, skb);
+       }
 }
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 65b11ea..119ecc5 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -385,6 +385,7 @@ int dccp_sendmsg(struct kiocb *iocb, str

        lock_sock(sk);
        timeo = sock_sndtimeo(sk, noblock);
+       /* FIXME imcdnzl - we should be using timeo for memory allocation */

        /*
         * We have to use sk_stream_wait_connect here to set sk_write_pending,
@@ -407,19 +408,13 @@ int dccp_sendmsg(struct kiocb *iocb, str
        if (rc != 0)
                goto out_discard;

-       rc = dccp_write_xmit(sk, skb, &timeo);
-       /*
-        * XXX we don't use sk_write_queue, so just discard the packet.
-        *     Current plan however is to _use_ sk_write_queue with
-        *     an algorith similar to tcp_sendmsg, where the main difference
-        *     is that in DCCP we have to respect packet boundaries, so
-        *     no coalescing of skbs.
-        *
-        *     This bug was _quickly_ found & fixed by just looking at an OSTRA
-        *     generated callgraph 8) -acme
-        */
+       skb_queue_tail(&sk->sk_write_queue, skb);
+       release_sock(sk);
+       dccp_write_xmit(sk,0);
+       goto out_end;
 out_release:
        release_sock(sk);
+out_end:
        return rc ? : len;
 out_discard:
        kfree_skb(skb);
@@ -591,6 +586,7 @@ static int dccp_close_state(struct sock

 void dccp_close(struct sock *sk, long timeout)
 {
+       struct dccp_sock *dp = dccp_sk(sk);
        struct sk_buff *skb;

        lock_sock(sk);
@@ -606,6 +602,8 @@ void dccp_close(struct sock *sk, long ti
                goto adjudge_to_death;
        }

+       del_timer_sync(&dp->dccps_xmit_timer);
+
        /*
         * We need to flush the recv. buffs.  We do this only on the
         * descriptor close, not protocol-sourced closes, because the
-
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