Re: [PATCH v2] net: Allow ethtool to set interface in loopback mode.
From: Mahesh Bandewar <hidden>
Date: 2011-01-07 00:47:09
On Thu, Jan 6, 2011 at 2:13 PM, Ben Hutchings [off-list ref] wrote:
On Wed, 2011-01-05 at 11:22 -0500, Jeff Garzik wrote:quoted
On 01/04/2011 08:21 PM, Ben Hutchings wrote:quoted
On Tue, 2011-01-04 at 16:36 -0800, Stephen Hemminger wrote:quoted
On Tue, 4 Jan 2011 16:30:01 -0800 Mahesh Bandewar[off-list ref] wrote:quoted
This patch enables ethtool to set the loopback mode on a given interface. By configuring the interface in loopback mode in conjunction with a policy route / rule, a userland application can stress the egress / ingress path exposing the flows of the change in progress and potentially help developer(s) understand the impact of those changes without even sending a packet out on the network. Following set of commands illustrates one such example - a) ip -4 addr add 192.168.1.1/24 dev eth1 b) ip -4 rule add from all iif eth1 lookup 250 c) ip -4 route add local 0/0 dev lo proto kernel scope host table 250 d) arp -Ds 192.168.1.100 eth1 e) arp -Ds 192.168.1.200 eth1 f) sysctl -w net.ipv4.ip_nonlocal_bind=1 g) sysctl -w net.ipv4.conf.all.accept_local=1 # Assuming that the machine has 8 cores h) taskset 000f netserver -L 192.168.1.200 i) taskset 00f0 netperf -t TCP_CRR -L 192.168.1.100 -H 192.168.1.200 -l 30 Signed-off-by: Mahesh Bandewar<redacted> Reviewed-by: Ben Hutchings<redacted>Since this is a boolean it SHOULD go into ethtool_flags rather than being a high level operation.It could do, but I though ETHTOOL_{G,S}FLAGS were intended for controlling offload features.It doesn't have to be. As Stephen guessed, [GS]FLAGS are basically common flags -- as differentiated from private, driver-specific/hardware-specific flags.Well, that would allow the patch to be simplified quite a bit. :-)
Ben, Are you suggesting to use ETH_FLAG_LOOPBACK instead of
ETHTOOL_{G|S}LOOPBACK flags?
Thanks,
--mahesh..
quoted hunk ↗ jump to hunk
Ben. From: Ben Hutchings <redacted> Subject: [PATCH net-2.6] ethtool: Define ETH_FLAG_LOOPBACK Date: Thu, 6 Jan 2011 22:10:55 +0000 Mahesh Bandewar [off-list ref] requested this, writing: By configuring the interface in loopback mode in conjunction with a policy route / rule, a userland application can stress the egress / ingress path exposing the flows of the change in progress and potentially help developer(s) understand the impact of those changes without even sending a packet out on the network. Signed-off-by: Ben Hutchings <redacted>--- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h@@ -309,6 +309,7 @@ struct ethtool_perm_addr {* flag differs from the read-only value. */ enum ethtool_flags { + ETH_FLAG_LOOPBACK = (1 << 2), /* Host-side loopback enabled */ ETH_FLAG_TXVLAN = (1 << 7), /* TX VLAN offload enabled */ ETH_FLAG_RXVLAN = (1 << 8), /* RX VLAN offload enabled */ ETH_FLAG_LRO = (1 << 15), /* LRO is enabled */ --- -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.