[net-next,3/3] sunvnet: generate ICMP PTMUD messages for smaller port MTUs

This patch sends ICMP and ICMPv6 messages for Path MTU Discovery when a remote
port MTU is smaller than the device MTU. This allows mixing newer VIO protocol
devices that support MTU negotiation with older devices that do not on the
same vswitch. It also allows Linux-Linux LDOMs to use 64K-1 data packets even
though Solaris vswitch is limited to <16K MTU.

Signed-off-by: David L Stevens <david.stevens@oracle.com>
---
 drivers/net/ethernet/sun/sunvnet.c |   35 +++++++++++++++++++++++++++++++++++
 1 files changed, 35 insertions(+), 0 deletions(-)

  	if (skb->len > port->vio.rmtu) {
+		unsigned long localmtu = port->vio.rmtu - ETH_HLEN;
+
+		if (port->vio.ver.major == 1 && port->vio.ver.minor >= 3)
+			localmtu -= VLAN_HLEN;
+
+		if (skb->protocol == htons(ETH_P_IP))
+		{
+			struct flowi4 fl4;
+			struct rtable *rt = NULL;
+
+			memset(&fl4, 0, sizeof(fl4));
+			fl4.flowi4_oif = dev->ifindex;
+			fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
+			fl4.daddr = ip_hdr(skb)->daddr;
+			fl4.saddr = ip_hdr(skb)->saddr;
+
+			rt = ip_route_output_key(dev_net(dev), &fl4);
+			if (!IS_ERR(rt)) {
+				skb_dst_set(skb, &rt->dst);
+				icmp_send(skb, ICMP_DEST_UNREACH,
+					  ICMP_FRAG_NEEDED,
+					  htonl(localmtu));
+			}
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
+#endif
 		goto out_dropped;
 	}
 -- 1.7.1

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From: David L Stevens <david.stevens@oracle.com>
Date: Fri, 12 Sep 2014 18:22:52 -0400

> +		if (skb->protocol == htons(ETH_P_IP))
> +		{

Openning braces should be on the same line as the if() statement.
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Hello.

On 9/13/2014 1:22 AM, David L Stevens wrote:

> This patch sends ICMP and ICMPv6 messages for Path MTU Discovery when a remote
> port MTU is smaller than the device MTU. This allows mixing newer VIO protocol
> devices that support MTU negotiation with older devices that do not on the
> same vswitch. It also allows Linux-Linux LDOMs to use 64K-1 data packets even
> though Solaris vswitch is limited to <16K MTU.

> Signed-off-by: David L Stevens <david.stevens@oracle.com>
> ---
>   drivers/net/ethernet/sun/sunvnet.c |   35 +++++++++++++++++++++++++++++++++++
>   1 files changed, 35 insertions(+), 0 deletions(-)

> diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
> index b557ec4..1251603 100644
> --- a/drivers/net/ethernet/sun/sunvnet.c
> +++ b/drivers/net/ethernet/sun/sunvnet.c
> @@ -17,6 +17,13 @@
>   #include <linux/mutex.h>
>   #include <linux/if_vlan.h>
>   +#if IS_ENABLED(CONFIG_IPV6)

    Patch spoiled as well...

> +#include <linux/icmpv6.h>
> +#endif
> +
> +#include <net/icmp.h>
> +#include <net/route.h>
> +
>   #include <asm/vio.h>
>   #include <asm/ldc.h>

WBR, Sergei

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On 09/13/2014 04:19 PM, Sergei Shtylyov wrote:

>    Patch spoiled as well...

Yes, it was mangled by my mailer. I think PATCHv3, the latest I sent, is
ok, but please try that. And, of course, let me know if it doesn't work.

						+-DLS


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