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Message-Id: <20240130214620.3722189-2-dw@davidwei.uk>
Date: Tue, 30 Jan 2024 13:46:17 -0800
From: David Wei <dw@...idwei.uk>
To: Jakub Kicinski <kuba@...nel.org>,
Jiri Pirko <jiri@...nulli.us>,
Sabrina Dubroca <sd@...asysnail.net>,
netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH net-next v8 1/4] 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: David Wei <dw@...idwei.uk>
---
drivers/net/netdevsim/bus.c | 132 ++++++++++++++++++++++++++++++
drivers/net/netdevsim/netdev.c | 11 +++
drivers/net/netdevsim/netdevsim.h | 2 +
3 files changed, 145 insertions(+)
diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
index bcbc1e19edde..57e28801bb51 100644
--- a/drivers/net/netdevsim/bus.c
+++ b/drivers/net/netdevsim/bus.c
@@ -232,9 +232,141 @@ 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)
+{
+ unsigned int netnsid_a, netnsid_b, ifidx_a, ifidx_b;
+ struct netdevsim *nsim_a, *nsim_b, *peer;
+ struct net_device *dev_a, *dev_b;
+ struct net *ns_a, *ns_b;
+ int err;
+
+ err = sscanf(buf, "%u:%u %u:%u", &netnsid_a, &ifidx_a, &netnsid_b, &ifidx_b);
+ if (err != 4) {
+ pr_err("Format for linking two devices is \"netnsid_a:ifidx_a netnsid_b:ifidx_b\" (uint uint unit uint).\n");
+ return -EINVAL;
+ }
+
+ err = -EINVAL;
+ rtnl_lock();
+ ns_a = get_net_ns_by_id(current->nsproxy->net_ns, netnsid_a);
+ if (!ns_a) {
+ pr_err("Could not find netns with id: %u\n", netnsid_a);
+ goto out_unlock_rtnl;
+ }
+
+ dev_a = __dev_get_by_index(ns_a, ifidx_a);
+ if (!dev_a) {
+ pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx_a, netnsid_a);
+ goto out_put_netns_a;
+ }
+
+ if (!netdev_is_nsim(dev_a)) {
+ pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx_a, netnsid_a);
+ goto out_put_netns_a;
+ }
+
+ ns_b = get_net_ns_by_id(current->nsproxy->net_ns, netnsid_b);
+ if (!ns_b) {
+ pr_err("Could not find netns with id: %u\n", netnsid_b);
+ goto out_put_netns_a;
+ }
+
+ dev_b = __dev_get_by_index(ns_b, ifidx_b);
+ if (!dev_b) {
+ pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx_b, netnsid_b);
+ goto out_put_netns_b;
+ }
+
+ if (!netdev_is_nsim(dev_b)) {
+ pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx_b, netnsid_b);
+ goto out_put_netns_b;
+ }
+
+ err = 0;
+ nsim_a = netdev_priv(dev_a);
+ peer = rtnl_dereference(nsim_a->peer);
+ if (peer) {
+ pr_err("Netdevsim %u:%u is already linked\n", netnsid_a, ifidx_a);
+ goto out_put_netns_b;
+ }
+
+ nsim_b = netdev_priv(dev_b);
+ peer = rtnl_dereference(nsim_b->peer);
+ if (peer) {
+ pr_err("Netdevsim %u:%u is already linked\n", netnsid_b, ifidx_b);
+ goto out_put_netns_b;
+ }
+
+ rcu_assign_pointer(nsim_a->peer, nsim_b);
+ rcu_assign_pointer(nsim_b->peer, nsim_a);
+
+out_put_netns_b:
+ put_net(ns_b);
+out_put_netns_a:
+ put_net(ns_a);
+out_unlock_rtnl:
+ 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;
+ unsigned int netnsid, ifidx;
+ struct net_device *dev;
+ struct net *ns;
+ int err;
+
+ err = sscanf(buf, "%u:%u", &netnsid, &ifidx);
+ if (err != 2) {
+ pr_err("Format for unlinking a device is \"netnsid:ifidx\" (uint uint).\n");
+ return -EINVAL;
+ }
+
+ err = -EINVAL;
+ rtnl_lock();
+ ns = get_net_ns_by_id(current->nsproxy->net_ns, netnsid);
+ if (!ns) {
+ pr_err("Could not find netns with id: %u\n", netnsid);
+ goto out_unlock_rtnl;
+ }
+
+ dev = __dev_get_by_index(ns, ifidx);
+ if (!dev) {
+ pr_err("Could not find device with ifindex %u in netnsid %u\n", ifidx, netnsid);
+ goto out_put_netns;
+ }
+
+ if (!netdev_is_nsim(dev)) {
+ pr_err("Device with ifindex %u in netnsid %u is not a netdevsim\n", ifidx, netnsid);
+ goto out_put_netns;
+ }
+
+ err = 0;
+ nsim = netdev_priv(dev);
+ peer = rtnl_dereference(nsim->peer);
+ if (!peer)
+ goto out_put_netns;
+
+ RCU_INIT_POINTER(nsim->peer, NULL);
+ RCU_INIT_POINTER(peer->peer, NULL);
+
+out_put_netns:
+ put_net(ns);
+out_unlock_rtnl:
+ 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);
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 77e8250282a5..57883773e4fb 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -333,6 +333,7 @@ static int nsim_init_netdevsim(struct netdevsim *ns)
goto err_phc_destroy;
rtnl_lock();
+ RCU_INIT_POINTER(ns->peer, NULL);
err = nsim_bpf_init(ns);
if (err)
goto err_utn_destroy;
@@ -413,8 +414,13 @@ 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 +433,11 @@ 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)
{
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 028c825b86db..c8b45b0d955e 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -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);
--
2.39.3
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