From f532957d76de89b8ee2545cb6ad5265e1701d0ba Mon Sep 17 00:00:00 2001 From: David Wei Date: Wed, 28 Feb 2024 15:22:49 -0800 Subject: 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 Reviewed-by: Maciek Machnikowski Signed-off-by: David S. Miller --- drivers/net/netdevsim/bus.c | 145 ++++++++++++++++++++++++++++++++++++++ drivers/net/netdevsim/netdev.c | 10 +++ drivers/net/netdevsim/netdevsim.h | 2 + 3 files changed, 157 insertions(+) diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c index 0c5aff63d242..64c0cdd31bf8 100644 --- a/drivers/net/netdevsim/bus.c +++ b/drivers/net/netdevsim/bus.c @@ -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); diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 77e8250282a5..9063f4f2971b 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -413,8 +413,13 @@ err_free_netdev: 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) { 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); -- cgit v1.2.3