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From: Ian McDonald <imcdnzl@gmail.com>
To: dccp@vger.kernel.org
Subject: [RFC] Move DCCP to buffers for transmitting
Date: Fri, 16 Dec 2005 04:01:12 +0000	[thread overview]
Message-ID: <cbec11ac0512152001q23fc0921jad5a920126bc8a4a@mail.gmail.com> (raw)

Folks,

I'm trying to change DCCP transmission to use buffers like TCP rather
than current mechanism.

This code is not yet quite ready as have kernel asserts as per below:
Dec 16 16:50:59 localhost kernel: KERNEL: assertion
(skb_queue_empty(&sk->sk_write_queue)) failed at net/core/stream.c
(277)
Dec 16 16:50:59 localhost kernel: KERNEL: assertion
(!sk->sk_wmem_queued) failed at net/core/stream.c (282)
Dec 16 16:50:59 localhost kernel: KERNEL: assertion
(!sk->sk_forward_alloc) failed at net/core/stream.c (283)
Dec 16 16:50:59 localhost kernel: KERNEL: assertion
(!sk->sk_wmem_queued) failed at net/ipv4/af_inet.c (147)
Dec 16 16:50:59 localhost kernel: KERNEL: assertion
(!sk->sk_forward_alloc) failed at net/ipv4/af_inet.c (148)

I thought I would get it out there for discussion as I am finishing
for weekend now probably and wouldn't mind feedback on general
principle of my code. This is against davem's net-2.6.16 as of a day
or so ago. Code still needs tidying up as well in style a little....

Ian
--
Ian McDonald
http://wand.net.nz/~iam4
WAND Network Research Group
University of Waikato
New Zealand

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
diff --git a/include/net/sock.h b/include/net/sock.h
index 91d2895..49bd617 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1053,6 +1053,23 @@ static inline void sk_charge_skb(struct
 	sk->sk_forward_alloc -= skb->truesize;
 }

+static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
+{
+	skb->csum = 0;
+	skb_header_release(skb);
+	__skb_queue_tail(&sk->sk_write_queue, skb);
+	sk_charge_skb(sk, skb);
+	if (!sk->sk_send_head)
+		sk->sk_send_head = skb;
+}
+
+static inline void skb_update_send_head(struct sock *sk, struct sk_buff *skb)
+{
+	sk->sk_send_head = skb->next;
+	if (sk->sk_send_head = (struct sk_buff *)&sk->sk_write_queue)
+		sk->sk_send_head = NULL;
+}
+
 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
 				   struct sk_buff *skb, struct page *page,
 				   int off, int copy)
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 93f26dd..3ecc417 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -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);
+extern void dccp_write_xmit(struct sock *sk);
 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 95a3c2c..1618106 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -26,12 +26,14 @@ static inline void dccp_event_ack_sent(s
 	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 }

+#if 0
 static inline void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
 {
 	skb_set_owner_w(skb, sk);
 	WARN_ON(sk->sk_send_head);
 	sk->sk_send_head = skb;
 }
+#endif

 /*
  * All SKB's seen here are completely headerless. It is our
@@ -226,37 +228,47 @@ do_interrupted:
 	goto out;
 }

-int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
+void dccp_write_xmit(struct sock *sk)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);
-	int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+	struct sk_buff *skb;
+	long timeo = 2000; /* fixme iancrap - 2 second default */
+
+	while ((skb = sk->sk_send_head)) {
+		int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
 					 skb->len);

-	if (err > 0)
-		err = dccp_wait_for_ccid(sk, skb, timeo);
+		if (err > 0)
+			err = dccp_wait_for_ccid(sk, skb, &timeo);

-	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,
+		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);
+				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);
+		}
+#if 0
+		} else
+			kfree_skb(skb);
+#endif
+		skb_update_send_head(sk, skb);
+	}
+#if 0
 	return err;
+#endif
 }

 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
@@ -414,7 +426,8 @@ int dccp_connect(struct sock *sk)
 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
 	skb->csum = 0;

-	dccp_skb_entail(sk, skb);
+	skb_entail(sk, skb);
+	/* iancrap */
 	dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
 	DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);

@@ -526,7 +539,8 @@ void dccp_send_close(struct sock *sk, co
 					DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;

 	if (active) {
-		dccp_skb_entail(sk, skb);
+		skb_entail(sk, skb);
+		/* iancrap */
 		dccp_transmit_skb(sk, skb_clone(skb, prio));
 	} else
 		dccp_transmit_skb(sk, skb);
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 40a4c68..c6a1138 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -387,6 +387,8 @@ int dccp_sendmsg(struct kiocb *iocb, str
 	lock_sock(sk);
 	timeo = sock_sndtimeo(sk, noblock);

+	/* iancrap - use timeo for memory allocation */
+
 	/*
 	 * We have to use sk_stream_wait_connect here to set sk_write_pending,
 	 * so that the trick in dccp_rcv_request_sent_state_process.
@@ -408,17 +410,9 @@ 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_entail(sk, skb);
+
+	dccp_write_xmit(sk);
 out_release:
 	release_sock(sk);
 	return rc ? : len;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 00aa80e..e0b53b4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -458,19 +458,14 @@ static inline int forced_push(struct tcp
 	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 }

-static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
+static inline void tcp_skb_entail(struct sock *sk, struct tcp_sock *tp,
 			      struct sk_buff *skb)
 {
-	skb->csum = 0;
+	skb_entail(sk,skb);
 	TCP_SKB_CB(skb)->seq = tp->write_seq;
 	TCP_SKB_CB(skb)->end_seq = tp->write_seq;
 	TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
 	TCP_SKB_CB(skb)->sacked = 0;
-	skb_header_release(skb);
-	__skb_queue_tail(&sk->sk_write_queue, skb);
-	sk_charge_skb(sk, skb);
-	if (!sk->sk_send_head)
-		sk->sk_send_head = skb;
 	if (tp->nonagle & TCP_NAGLE_PUSH)
 		tp->nonagle &= ~TCP_NAGLE_PUSH;
 }
@@ -539,7 +534,7 @@ new_segment:
 			if (!skb)
 				goto wait_for_memory;

-			skb_entail(sk, tp, skb);
+			tcp_skb_entail(sk, tp, skb);
 			copy = size_goal;
 		}

@@ -730,7 +725,7 @@ new_segment:
 				     NETIF_F_HW_CSUM))
 					skb->ip_summed = CHECKSUM_HW;

-				skb_entail(sk, tp, skb);
+				tcp_skb_entail(sk, tp, skb);
 				copy = size_goal;
 			}

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 3a0a914..1ec9128 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -51,12 +51,10 @@ int sysctl_tcp_retrans_collapse = 1;
  */
 int sysctl_tcp_tso_win_divisor = 3;

-static inline void update_send_head(struct sock *sk, struct tcp_sock *tp,
+static inline void tcp_update_send_head(struct sock *sk, struct tcp_sock *tp,
 				    struct sk_buff *skb)
 {
-	sk->sk_send_head = skb->next;
-	if (sk->sk_send_head = (struct sk_buff *)&sk->sk_write_queue)
-		sk->sk_send_head = NULL;
+	skb_update_send_head(sk, skb);
 	tp->snd_nxt = TCP_SKB_CB(skb)->end_seq;
 	tcp_packets_out_inc(sk, tp, skb);
 }
@@ -1060,7 +1058,7 @@ static int tcp_write_xmit(struct sock *s
 		/* Advance the send_head.  This one is sent out.
 		 * This call will increment packets_out.
 		 */
-		update_send_head(sk, tp, skb);
+		tcp_update_send_head(sk, tp, skb);

 		tcp_minshall_update(tp, mss_now, skb);
 		sent_pkts++;
@@ -1128,7 +1126,7 @@ void tcp_push_one(struct sock *sk, unsig
 		TCP_SKB_CB(skb)->when = tcp_time_stamp;

 		if (likely(!tcp_transmit_skb(sk, skb, 1, sk->sk_allocation))) {
-			update_send_head(sk, tp, skb);
+			tcp_update_send_head(sk, tp, skb);
 			tcp_cwnd_validate(sk, tp);
 			return;
 		}
@@ -2048,7 +2046,7 @@ int tcp_write_wakeup(struct sock *sk)
 			TCP_SKB_CB(skb)->when = tcp_time_stamp;
 			err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 			if (!err) {
-				update_send_head(sk, tp, skb);
+				tcp_update_send_head(sk, tp, skb);
 			}
 			return err;
 		} else {

                 reply	other threads:[~2005-12-16  4:01 UTC|newest]

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