Commit f532957d authored by David Wei's avatar David Wei Committed by David S. Miller
Browse files

netdevsim: allow two netdevsim ports to be connected 



Add two netdevsim bus attribute to sysfs:
/sys/bus/netdevsim/link_device
/sys/bus/netdevsim/unlink_device

Writing "A M B N" to link_device will link netdevsim M in netnsid A with
netdevsim N in netnsid B.

Writing "A M" to unlink_device will unlink netdevsim M in netnsid A from
its peer, if any.

rtnl_lock is taken to ensure nothing changes during the linking.

Signed-off-by: default avatarDavid Wei <dw@davidwei.uk>
Reviewed-by: default avatarMaciek Machnikowski <maciek@machnikowski.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e2d890af

drivers/net/netdevsim/bus.c

+145 −0
Original line number Diff line number Diff line
@@ -232,9 +232,154 @@ del_device_store(const struct bus_type *bus, const char *buf, size_t count) 
}

static BUS_ATTR_WO(del_device);



static ssize_t link_device_store(const struct bus_type *bus, const char *buf, size_t count)

{

	struct netdevsim *nsim_a, *nsim_b, *peer;

	struct net_device *dev_a, *dev_b;

	unsigned int ifidx_a, ifidx_b;

	int netnsfd_a, netnsfd_b, err;

	struct net *ns_a, *ns_b;



	err = sscanf(buf, "%d:%u %d:%u", &netnsfd_a, &ifidx_a, &netnsfd_b,

		     &ifidx_b);

	if (err != 4) {

		pr_err("Format for linking two devices is \"netnsfd_a:ifidx_a netnsfd_b:ifidx_b\" (int uint int uint).\n");

		return -EINVAL;

	}



	ns_a = get_net_ns_by_fd(netnsfd_a);

	if (IS_ERR(ns_a)) {

		pr_err("Could not find netns with fd: %d\n", netnsfd_a);

		return -EINVAL;

	}



	ns_b = get_net_ns_by_fd(netnsfd_b);

	if (IS_ERR(ns_b)) {

		pr_err("Could not find netns with fd: %d\n", netnsfd_b);

		put_net(ns_a);

		return -EINVAL;

	}



	err = -EINVAL;

	rtnl_lock();

	dev_a = __dev_get_by_index(ns_a, ifidx_a);

	if (!dev_a) {

		pr_err("Could not find device with ifindex %u in netnsfd %d\n",

		       ifidx_a, netnsfd_a);

		goto out_err;

	}



	if (!netdev_is_nsim(dev_a)) {

		pr_err("Device with ifindex %u in netnsfd %d is not a netdevsim\n",

		       ifidx_a, netnsfd_a);

		goto out_err;

	}



	dev_b = __dev_get_by_index(ns_b, ifidx_b);

	if (!dev_b) {

		pr_err("Could not find device with ifindex %u in netnsfd %d\n",

		       ifidx_b, netnsfd_b);

		goto out_err;

	}



	if (!netdev_is_nsim(dev_b)) {

		pr_err("Device with ifindex %u in netnsfd %d is not a netdevsim\n",

		       ifidx_b, netnsfd_b);

		goto out_err;

	}



	if (dev_a == dev_b) {

		pr_err("Cannot link a netdevsim to itself\n");

		goto out_err;

	}



	err = -EBUSY;

	nsim_a = netdev_priv(dev_a);

	peer = rtnl_dereference(nsim_a->peer);

	if (peer) {

		pr_err("Netdevsim %d:%u is already linked\n", netnsfd_a,

		       ifidx_a);

		goto out_err;

	}



	nsim_b = netdev_priv(dev_b);

	peer = rtnl_dereference(nsim_b->peer);

	if (peer) {

		pr_err("Netdevsim %d:%u is already linked\n", netnsfd_b,

		       ifidx_b);

		goto out_err;

	}



	err = 0;

	rcu_assign_pointer(nsim_a->peer, nsim_b);

	rcu_assign_pointer(nsim_b->peer, nsim_a);



out_err:

	put_net(ns_b);

	put_net(ns_a);

	rtnl_unlock();



	return !err ? count : err;

}

static BUS_ATTR_WO(link_device);



static ssize_t unlink_device_store(const struct bus_type *bus, const char *buf, size_t count)

{

	struct netdevsim *nsim, *peer;

	struct net_device *dev;

	unsigned int ifidx;

	int netnsfd, err;

	struct net *ns;



	err = sscanf(buf, "%u:%u", &netnsfd, &ifidx);

	if (err != 2) {

		pr_err("Format for unlinking a device is \"netnsfd:ifidx\" (int uint).\n");

		return -EINVAL;

	}



	ns = get_net_ns_by_fd(netnsfd);

	if (IS_ERR(ns)) {

		pr_err("Could not find netns with fd: %d\n", netnsfd);

		return -EINVAL;

	}



	err = -EINVAL;

	rtnl_lock();

	dev = __dev_get_by_index(ns, ifidx);

	if (!dev) {

		pr_err("Could not find device with ifindex %u in netnsfd %d\n",

		       ifidx, netnsfd);

		goto out_put_netns;

	}



	if (!netdev_is_nsim(dev)) {

		pr_err("Device with ifindex %u in netnsfd %d is not a netdevsim\n",

		       ifidx, netnsfd);

		goto out_put_netns;

	}



	nsim = netdev_priv(dev);

	peer = rtnl_dereference(nsim->peer);

	if (!peer)

		goto out_put_netns;



	err = 0;

	RCU_INIT_POINTER(nsim->peer, NULL);

	RCU_INIT_POINTER(peer->peer, NULL);



out_put_netns:

	put_net(ns);

	rtnl_unlock();



	return !err ? count : err;

}

static BUS_ATTR_WO(unlink_device);



static struct attribute *nsim_bus_attrs[] = {

	&bus_attr_new_device.attr,

	&bus_attr_del_device.attr,

	&bus_attr_link_device.attr,

	&bus_attr_unlink_device.attr,

	NULL

};

ATTRIBUTE_GROUPS(nsim_bus);

drivers/net/netdevsim/netdev.c

+10 −0
Original line number Diff line number Diff line
@@ -413,8 +413,13 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port) 
void nsim_destroy(struct netdevsim *ns)

{

	struct net_device *dev = ns->netdev;

	struct netdevsim *peer;



	rtnl_lock();

	peer = rtnl_dereference(ns->peer);

	if (peer)

		RCU_INIT_POINTER(peer->peer, NULL);

	RCU_INIT_POINTER(ns->peer, NULL);

	unregister_netdevice(dev);

	if (nsim_dev_port_is_pf(ns->nsim_dev_port)) {

		nsim_macsec_teardown(ns);
@@ -427,6 +432,11 @@ void nsim_destroy(struct netdevsim *ns) 
	free_netdev(dev);

}



bool netdev_is_nsim(struct net_device *dev)

{

	return dev->netdev_ops == &nsim_netdev_ops;

}



static int nsim_validate(struct nlattr *tb[], struct nlattr *data[],

			 struct netlink_ext_ack *extack)

{

drivers/net/netdevsim/netdevsim.h

+2 −0
Original line number Diff line number Diff line
@@ -125,11 +125,13 @@ struct netdevsim { 
	} udp_ports;



	struct nsim_ethtool ethtool;

	struct netdevsim __rcu *peer;

};



struct netdevsim *

nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port);

void nsim_destroy(struct netdevsim *ns);

bool netdev_is_nsim(struct net_device *dev);



void nsim_ethtool_init(struct netdevsim *ns);