| Message ID | 1304471935-402-2-git-send-email-maheshb@google.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, May 03, 2011 at 06:18:54PM -0700, Mahesh Bandewar wrote: > 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 <maheshb@google.com> > --- > include/linux/netdevice.h | 3 ++- > net/core/ethtool.c | 2 +- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index d5de66a..e7244ed 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1067,6 +1067,7 @@ struct net_device { > #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ > #define NETIF_F_RXCSUM (1 << 29) /* Receive checksumming offload */ > #define NETIF_F_NOCACHE_COPY (1 << 30) /* Use no-cache copyfromuser */ > +#define NETIF_F_LOOPBACK (1 << 31) /* Enable loopback */ [...] Just for correctness: you could add this flag to loopback's dev->features. It's just an aesthetics point, though. Best Regards, Michał Mirosław -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index d5de66a..e7244ed 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1067,6 +1067,7 @@ struct net_device { #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ #define NETIF_F_RXCSUM (1 << 29) /* Receive checksumming offload */ #define NETIF_F_NOCACHE_COPY (1 << 30) /* Use no-cache copyfromuser */ +#define NETIF_F_LOOPBACK (1 << 31) /* Enable loopback */ /* Segmentation offload features */ #define NETIF_F_GSO_SHIFT 16 @@ -1082,7 +1083,7 @@ struct net_device { /* = all defined minus driver/device-class-related */ #define NETIF_F_NEVER_CHANGE (NETIF_F_VLAN_CHALLENGED | \ NETIF_F_LLTX | NETIF_F_NETNS_LOCAL) -#define NETIF_F_ETHTOOL_BITS (0x7f3fffff & ~NETIF_F_NEVER_CHANGE) +#define NETIF_F_ETHTOOL_BITS (0xff3fffff & ~NETIF_F_NEVER_CHANGE) /* List of features with software fallbacks. */ #define NETIF_F_GSO_SOFTWARE (NETIF_F_TSO | NETIF_F_TSO_ECN | \ diff --git a/net/core/ethtool.c b/net/core/ethtool.c index d8b1a8d..f26649d 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -362,7 +362,7 @@ static const char netdev_features_strings[ETHTOOL_DEV_FEATURE_WORDS * 32][ETH_GS /* NETIF_F_RXHASH */ "rx-hashing", /* NETIF_F_RXCSUM */ "rx-checksum", /* NETIF_F_NOCACHE_COPY */ "tx-nocache-copy" - "", + /* NETIF_F_LOOPBACK */ "loopback", }; static int __ethtool_get_sset_count(struct net_device *dev, int sset)
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 <maheshb@google.com> --- include/linux/netdevice.h | 3 ++- net/core/ethtool.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)