[PATCH 2.6.17] support for TSO over IPv6

[PATCH 2.6.17] support for TSO over IPv6

[Ananda Raju]

Hi, 
	This patch enables TSO over IPv6. Currently Linux network stacks
	restricts TSO over IPv6 by clearing of the NETIF_F_TSO bit from
	"dev->features". This patch will remove this restriction.

	This patch will introduce a new flag NETIF_F_TSO6 which will be used 
	to check whether device supports TSO over IPv6. If device support TSO
	over IPv6 then we don't clear of NETIF_F_TSO and which will make the 
	TCP layer to create TSO packets. Any device supporting TSO over IPv6 
	will set NETIF_F_TSO6 flag in "dev->features" along with NETIF_F_TSO.

	In case when user disables TSO using ethtool, NETIF_F_TSO will get
	cleared from "dev->features". So even if we have NETIF_F_TSO6 we don't
	get TSO packets created by TCP layer. 

	SKB_GSO_TCPV4 renamed to SKB_GSO_TCP to make it generic GSO packet.
	SKB_GSO_UDPV4 renamed to SKB_GSO_UDP as UFO is not a IPv4 feature.
	UFO is supported over IPv6 also

	The following table shows there is significant improvement in
	throughput with normal frames and CPU usage for both normal and jumbo.

        --------------------------------------------------
        |          |     1500        |      9600         |
        |          ------------------|-------------------|
        |          | thru     CPU    |  thru     CPU     |
        --------------------------------------------------
        | TSO OFF  | 2.00   5.5% id  |  5.66   20.0% id   |
        --------------------------------------------------
        | TSO ON   | 2.63   78.0 id  |  5.67   39.0% id  |
        --------------------------------------------------

Please review the patch.
Signed-off-by: Ananda Raju <ananda.raju@neterion.com>
---
diff -upNr netdev.org/drivers/net/s2io.c netdev.ipv6_tso/drivers/net/s2io.c
--- netdev.org/drivers/net/s2io.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/drivers/net/s2io.c	2006-06-27 07:38:48.000000000 -0700
@@ -3960,7 +3960,7 @@ static int s2io_xmit(struct sk_buff *skb
 	txdp->Control_2 = 0;
 #ifdef NETIF_F_TSO
 	mss = skb_shinfo(skb)->gso_size;
-	if (skb_shinfo(skb)->gso_type == SKB_GSO_TCPV4) {
+	if (skb_shinfo(skb)->gso_type == SKB_GSO_TCP) {
 		txdp->Control_1 |= TXD_TCP_LSO_EN;
 		txdp->Control_1 |= TXD_TCP_LSO_MSS(mss);
 	}
@@ -3980,7 +3980,7 @@ static int s2io_xmit(struct sk_buff *skb
 	}
 
 	frg_len = skb->len - skb->data_len;
-	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDPV4) {
+	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDP) {
 		int ufo_size;
 
 		ufo_size = skb_shinfo(skb)->gso_size;
@@ -4009,7 +4009,7 @@ static int s2io_xmit(struct sk_buff *skb
 	txdp->Host_Control = (unsigned long) skb;
 	txdp->Control_1 |= TXD_BUFFER0_SIZE(frg_len);
 
-	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDPV4)
+	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDP)
 		txdp->Control_1 |= TXD_UFO_EN;
 
 	frg_cnt = skb_shinfo(skb)->nr_frags;
@@ -4024,12 +4024,12 @@ static int s2io_xmit(struct sk_buff *skb
 		    (sp->pdev, frag->page, frag->page_offset,
 		     frag->size, PCI_DMA_TODEVICE);
 		txdp->Control_1 = TXD_BUFFER0_SIZE(frag->size);
-		if (skb_shinfo(skb)->gso_type == SKB_GSO_UDPV4)
+		if (skb_shinfo(skb)->gso_type == SKB_GSO_UDP)
 			txdp->Control_1 |= TXD_UFO_EN;
 	}
 	txdp->Control_1 |= TXD_GATHER_CODE_LAST;
 
-	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDPV4)
+	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDP)
 		frg_cnt++; /* as Txd0 was used for inband header */
 
 	tx_fifo = mac_control->tx_FIFO_start[queue];
@@ -4043,7 +4043,7 @@ static int s2io_xmit(struct sk_buff *skb
 	if (mss)
 		val64 |= TX_FIFO_SPECIAL_FUNC;
 #endif
-	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDPV4)
+	if (skb_shinfo(skb)->gso_type == SKB_GSO_UDP)
 		val64 |= TX_FIFO_SPECIAL_FUNC;
 	writeq(val64, &tx_fifo->List_Control);
 
@@ -7021,6 +7021,9 @@ s2io_init_nic(struct pci_dev *pdev, cons
 #ifdef NETIF_F_TSO
 	dev->features |= NETIF_F_TSO;
 #endif
+#ifdef NETIF_F_TSO6
+	dev->features |= NETIF_F_TSO6;
+#endif
 	if (sp->device_type & XFRAME_II_DEVICE) {
 		dev->features |= NETIF_F_UFO;
 		dev->features |= NETIF_F_HW_CSUM;
diff -upNr netdev.org/include/linux/netdevice.h netdev.ipv6_tso/include/linux/netdevice.h
--- netdev.org/include/linux/netdevice.h	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/include/linux/netdevice.h	2006-06-27 07:38:48.000000000 -0700
@@ -313,8 +313,9 @@ struct net_device
 
 	/* Segmentation offload features */
 #define NETIF_F_GSO_SHIFT	16
-#define NETIF_F_TSO		(SKB_GSO_TCPV4 << NETIF_F_GSO_SHIFT)
-#define NETIF_F_UFO		(SKB_GSO_UDPV4 << NETIF_F_GSO_SHIFT)
+#define NETIF_F_TSO		(SKB_GSO_TCP << NETIF_F_GSO_SHIFT)
+#define NETIF_F_UFO		(SKB_GSO_UDP << NETIF_F_GSO_SHIFT)
+#define NETIF_F_TSO6		(SKB_GSO_TCPV6 << NETIF_F_GSO_SHIFT)
 
 #define NETIF_F_GEN_CSUM	(NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
 #define NETIF_F_ALL_CSUM	(NETIF_F_IP_CSUM | NETIF_F_GEN_CSUM)
diff -upNr netdev.org/include/linux/skbuff.h netdev.ipv6_tso/include/linux/skbuff.h
--- netdev.org/include/linux/skbuff.h	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/include/linux/skbuff.h	2006-06-27 07:38:48.000000000 -0700
@@ -170,8 +170,9 @@ enum {
 };
 
 enum {
-	SKB_GSO_TCPV4 = 1 << 0,
-	SKB_GSO_UDPV4 = 1 << 1,
+	SKB_GSO_TCP = 1 << 0,
+	SKB_GSO_UDP = 1 << 1,
+	SKB_GSO_TCPV6 = 1 << 2,
 };
 
 /** 
diff -upNr netdev.org/net/ipv4/ip_output.c netdev.ipv6_tso/net/ipv4/ip_output.c
--- netdev.org/net/ipv4/ip_output.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv4/ip_output.c	2006-06-27 07:38:48.000000000 -0700
@@ -744,7 +744,7 @@ static inline int ip_ufo_append_data(str
 	if (!err) {
 		/* specify the length of each IP datagram fragment*/
 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
-		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 		__skb_queue_tail(&sk->sk_write_queue, skb);
 
 		return 0;
@@ -1089,7 +1089,7 @@ ssize_t	ip_append_page(struct sock *sk, 
 	if ((sk->sk_protocol == IPPROTO_UDP) &&
 	    (rt->u.dst.dev->features & NETIF_F_UFO)) {
 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
-		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 	}
 
 
diff -upNr netdev.org/net/ipv4/tcp_output.c netdev.ipv6_tso/net/ipv4/tcp_output.c
--- netdev.org/net/ipv4/tcp_output.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv4/tcp_output.c	2006-06-27 07:38:48.000000000 -0700
@@ -525,7 +525,7 @@ static void tcp_set_skb_tso_segs(struct 
 		factor /= mss_now;
 		skb_shinfo(skb)->gso_segs = factor;
 		skb_shinfo(skb)->gso_size = mss_now;
-		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+		skb_shinfo(skb)->gso_type = SKB_GSO_TCP;
 	}
 }
 
diff -upNr netdev.org/net/ipv6/af_inet6.c netdev.ipv6_tso/net/ipv6/af_inet6.c
--- netdev.org/net/ipv6/af_inet6.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv6/af_inet6.c	2006-06-27 07:38:48.000000000 -0700
@@ -660,8 +660,11 @@ int inet6_sk_rebuild_header(struct sock 
 		}
 
 		ip6_dst_store(sk, dst, NULL);
-		sk->sk_route_caps = dst->dev->features &
-			~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+		if (dst->dev->features & NETIF_F_TSO6)
+			sk->sk_route_caps = dst->dev->features;
+		else
+			sk->sk_route_caps = dst->dev->features &
+					~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 	}
 
 	return 0;
diff -upNr netdev.org/net/ipv6/inet6_connection_sock.c netdev.ipv6_tso/net/ipv6/inet6_connection_sock.c
--- netdev.org/net/ipv6/inet6_connection_sock.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv6/inet6_connection_sock.c	2006-06-27 07:38:48.000000000 -0700
@@ -187,8 +187,11 @@ int inet6_csk_xmit(struct sk_buff *skb, 
 		}
 
 		ip6_dst_store(sk, dst, NULL);
-		sk->sk_route_caps = dst->dev->features &
-			~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+		if (dst->dev->features & NETIF_F_TSO6)
+			sk->sk_route_caps = dst->dev->features;
+		else
+			sk->sk_route_caps = dst->dev->features &
+				~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 	}
 
 	skb->dst = dst_clone(dst);
diff -upNr netdev.org/net/ipv6/ip6_output.c netdev.ipv6_tso/net/ipv6/ip6_output.c
--- netdev.org/net/ipv6/ip6_output.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv6/ip6_output.c	2006-06-27 07:38:48.000000000 -0700
@@ -230,7 +230,7 @@ int ip6_xmit(struct sock *sk, struct sk_
 	skb->priority = sk->sk_priority;
 
 	mtu = dst_mtu(dst);
-	if ((skb->len <= mtu) || ipfragok) {
+	if ((skb->len <= mtu) || ipfragok || skb_shinfo(skb)->gso_size) {
 		IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
 		return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
 				dst_output);
@@ -835,7 +835,7 @@ static inline int ip6_ufo_append_data(st
 		/* specify the length of each IP datagram fragment*/
 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 
 					    sizeof(struct frag_hdr);
-		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 		ipv6_select_ident(skb, &fhdr);
 		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
 		__skb_queue_tail(&sk->sk_write_queue, skb);
diff -upNr netdev.org/net/ipv6/tcp_ipv6.c netdev.ipv6_tso/net/ipv6/tcp_ipv6.c
--- netdev.org/net/ipv6/tcp_ipv6.c	2006-06-27 07:30:36.000000000 -0700
+++ netdev.ipv6_tso/net/ipv6/tcp_ipv6.c	2006-06-27 07:38:48.000000000 -0700
@@ -271,8 +271,11 @@ static int tcp_v6_connect(struct sock *s
 	inet->rcv_saddr = LOOPBACK4_IPV6;
 
 	ip6_dst_store(sk, dst, NULL);
-	sk->sk_route_caps = dst->dev->features &
-		~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+	if (dst->dev->features & NETIF_F_TSO6)
+		sk->sk_route_caps = dst->dev->features;
+	else
+		sk->sk_route_caps = dst->dev->features &
+				~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
 	icsk->icsk_ext_hdr_len = 0;
 	if (np->opt)
@@ -931,8 +934,11 @@ static struct sock * tcp_v6_syn_recv_soc
 	 */
 
 	ip6_dst_store(newsk, dst, NULL);
-	newsk->sk_route_caps = dst->dev->features &
-		~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+	if (dst->dev->features & NETIF_F_TSO6)
+		sk->sk_route_caps = dst->dev->features;
+	else
+		newsk->sk_route_caps = dst->dev->features &
+				~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
 	newtcp6sk = (struct tcp6_sock *)newsk;
 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;

Re: [PATCH 2.6.17] support for TSO over IPv6

[David Miller]

From: Ananda Raju <Ananda.Raju@neterion.com>
Date: Thu, 29 Jun 2006 18:18:10 -0400 (EDT)

> 	This patch enables TSO over IPv6. Currently Linux network stacks
> 	restricts TSO over IPv6 by clearing of the NETIF_F_TSO bit from
> 	"dev->features". This patch will remove this restriction.

Generally this looks very good.

Since Herbert Xu has been playing a bit in this area, I'd like
to hear some feedback from him before I apply this.

Re: [PATCH 2.6.17] support for TSO over IPv6

[Herbert Xu]

Ananda Raju <Ananda.Raju@neterion.com> wrote:
>        This patch enables TSO over IPv6. Currently Linux network stacks
>        restricts TSO over IPv6 by clearing of the NETIF_F_TSO bit from
>        "dev->features". This patch will remove this restriction.

Thanks, looks good over all.
 
>        SKB_GSO_TCPV4 renamed to SKB_GSO_TCP to make it generic GSO packet.
>        SKB_GSO_UDPV4 renamed to SKB_GSO_UDP as UFO is not a IPv4 feature.
>        UFO is supported over IPv6 also

This bit is wrong though.  TCPv4 and TCPv6 packets can't share the same
GSO feature bit.  The reason is that GSO/TSO is no longer just activated
by dev->features.  Bridges can forward GSO/TSO packets through at any time.
This is why it is crucial that each packet specficies exactly the features
that it requires from the hardware.

For UFO, it's OK to have just SKB_GSO_UDP since IIRC your card is the only
one that supports it and it supports both protocols anyway.

> diff -upNr netdev.org/include/linux/skbuff.h netdev.ipv6_tso/include/linux/skbuff.h
> --- netdev.org/include/linux/skbuff.h   2006-06-27 07:30:36.000000000 -0700
> +++ netdev.ipv6_tso/include/linux/skbuff.h      2006-06-27 07:38:48.000000000 -0700
> @@ -170,8 +170,9 @@ enum {
> };
> 
> enum {
> -       SKB_GSO_TCPV4 = 1 << 0,
> -       SKB_GSO_UDPV4 = 1 << 1,
> +       SKB_GSO_TCP = 1 << 0,
> +       SKB_GSO_UDP = 1 << 1,
> +       SKB_GSO_TCPV6 = 1 << 2,
> };

BTW, you should rediff against Dave's current tree which has a few
extra bits there.

You should also leave TCPV4 as is and just add the TCPV6 bit.
 
> diff -upNr netdev.org/net/ipv4/tcp_output.c netdev.ipv6_tso/net/ipv4/tcp_output.c
> --- netdev.org/net/ipv4/tcp_output.c    2006-06-27 07:30:36.000000000 -0700
> +++ netdev.ipv6_tso/net/ipv4/tcp_output.c       2006-06-27 07:38:48.000000000 -0700
> @@ -525,7 +525,7 @@ static void tcp_set_skb_tso_segs(struct 
>                factor /= mss_now;
>                skb_shinfo(skb)->gso_segs = factor;
>                skb_shinfo(skb)->gso_size = mss_now;
> -               skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
> +               skb_shinfo(skb)->gso_type = SKB_GSO_TCP;

You need to set SKB_GSO_TCPV6 for IPv6 packets here.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 2.6.17] support for TSO over IPv6

[David Miller]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 30 Jun 2006 09:32:44 +1000

> BTW, you should rediff against Dave's current tree which has a few
> extra bits there.

I just rebased that, so feel free to use it as the base for
the patch now.

Re: [PATCH 2.6.17] support for TSO over IPv6

[Herbert Xu]

On Fri, Jun 30, 2006 at 09:32:44AM +1000, Herbert Xu wrote:
> 
> > diff -upNr netdev.org/include/linux/skbuff.h netdev.ipv6_tso/include/linux/skbuff.h
> > --- netdev.org/include/linux/skbuff.h   2006-06-27 07:30:36.000000000 -0700
> > +++ netdev.ipv6_tso/include/linux/skbuff.h      2006-06-27 07:38:48.000000000 -0700
> > @@ -170,8 +170,9 @@ enum {
> > };
> > 
> > enum {
> > -       SKB_GSO_TCPV4 = 1 << 0,
> > -       SKB_GSO_UDPV4 = 1 << 1,
> > +       SKB_GSO_TCP = 1 << 0,
> > +       SKB_GSO_UDP = 1 << 1,
> > +       SKB_GSO_TCPV6 = 1 << 2,
> > };
> 
> BTW, you should rediff against Dave's current tree which has a few
> extra bits there.
> 
> You should also leave TCPV4 as is and just add the TCPV6 bit.

BTW, does your card handle ECN correctly? If not then we should change
the new ECN bit to apply to both TCPv4 and TCPv6 since

1) We now have a piece of hardware that handles TSO6 and it doesn't do ECN.
2) It's quite likely that if the NIC can handle ECN in TCPv4 then it can do
   it in TCPv6.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 2.6.17] support for TSO over IPv6

[Michael Chan]

On Fri, 2006-06-30 at 10:39 +1000, Herbert Xu wrote:

> BTW, does your card handle ECN correctly? If not then we should change
> the new ECN bit to apply to both TCPv4 and TCPv6 since
> 
> 1) We now have a piece of hardware that handles TSO6 and it doesn't do ECN.
> 2) It's quite likely that if the NIC can handle ECN in TCPv4 then it can do
>    it in TCPv6.

Don't we have a bigger problem if it doesn't support ECN with ipv6 TSO?
We either have to disable ECN when TSO is enabled like we used to for
ipv4, or provide the gso tcp segmentation for ipv6.  Right?

Re: [PATCH 2.6.17] support for TSO over IPv6

[Herbert Xu]

On Thu, Jun 29, 2006 at 07:06:51PM -0700, Michael Chan wrote:
>
> Don't we have a bigger problem if it doesn't support ECN with ipv6 TSO?
> We either have to disable ECN when TSO is enabled like we used to for
> ipv4, or provide the gso tcp segmentation for ipv6.  Right?

Good point.  In that case we should also add GSO for IPv6.  It shouldn't
be too bad because all we need to do is verify the integrity of the
extension headers in terms of their length, not their content.

I wonder if this chip handles all the extension headers or not.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

RE: [PATCH 2.6.17] support for TSO over IPv6

[Leonid Grossman]

 

> -----Original Message-----
> From: Herbert Xu [mailto:herbert@gondor.apana.org.au] 
> Sent: Thursday, June 29, 2006 5:39 PM
> To: Ananda Raju
> Cc: netdev@vger.kernel.org; jgarzik@pobox.com; 
> shemminger@osdl.org; Leonid Grossman; Ravinandan Arakali; 
> sivakumar.subramani@neterion.com; Sriram Rapuru; Michael Chan
> Subject: Re: [PATCH 2.6.17] support for TSO over IPv6
> 
> BTW, does your card handle ECN correctly? If not then we 
> should change the new ECN bit to apply to both TCPv4 and TCPv6 since
> 
> 1) We now have a piece of hardware that handles TSO6 and it 
> doesn't do ECN.
> 2) It's quite likely that if the NIC can handle ECN in TCPv4 
> then it can do
>    it in TCPv6.

Hi Herbert,
For TSO, our current ASIC replicates the two bits (ECE and CWR) across
every datagram sent out. 
Are we saying that the correct behavior should be:

If ECE == 1, then set it to one for all datagrams.
If CWR == 1, then set it to one for the first datagram, and set it to
zero for the rest?

Thanks,
Leonid


> 
> Cheers,
> --
> Visit Openswan at http://www.openswan.org/
> Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> 
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
> 

Re: [PATCH 2.6.17] support for TSO over IPv6

[Herbert Xu]

Hi Leonid:

On Fri, Jun 30, 2006 at 04:46:56PM -0400, Leonid Grossman wrote:
> 
> If ECE == 1, then set it to one for all datagrams.
> If CWR == 1, then set it to one for the first datagram, and set it to
> zero for the rest?

Exactly.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

RE: [PATCH 2.6.17] support for TSO over IPv6

[Leonid Grossman]

Thanks Herbert!
We'll fix this.

Leonid 

> -----Original Message-----
> From: Herbert Xu [mailto:herbert@gondor.apana.org.au] 
> Sent: Friday, June 30, 2006 8:38 PM
> To: Leonid Grossman
> Cc: Ananda Raju; netdev@vger.kernel.org; jgarzik@pobox.com; 
> shemminger@osdl.org; Ravinandan Arakali; 
> sivakumar.subramani@neterion.com; Sriram Rapuru; Michael Chan
> Subject: Re: [PATCH 2.6.17] support for TSO over IPv6
> 
> Hi Leonid:
> 
> On Fri, Jun 30, 2006 at 04:46:56PM -0400, Leonid Grossman wrote:
> > 
> > If ECE == 1, then set it to one for all datagrams.
> > If CWR == 1, then set it to one for the first datagram, and 
> set it to 
> > zero for the rest?
> 
> Exactly.
> 
> Cheers,
> --
> Visit Openswan at http://www.openswan.org/
> Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> 
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>