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sunvnet: generate ICMP PTMUD messages for smaller port MTUs

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David L Stevens 2014-09-29 19:48:24 -04:00 committed by David S. Miller
parent 42db672dca
commit a2b78e9b2c
1 changed files with 36 additions and 1 deletions
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37
drivers/net/ethernet/sun/sunvnet.c
View File

@ -17,6 +17,13 @@
#include <linux/mutex.h>
#include <linux/if_vlan.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/icmpv6.h>
#endif
#include <net/icmp.h>
#include <net/route.h>
#include <asm/vio.h>
#include <asm/ldc.h>
@ -913,8 +920,36 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (unlikely(!skb))
goto out_dropped;
if (skb->len > port->rmtu)
if (skb->len > port->rmtu) {
unsigned long localmtu = port->rmtu - ETH_HLEN;
if (vio_version_after_eq(&port->vio, 1, 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;
}
spin_lock_irqsave(&port->vio.lock, flags);