diff options
Diffstat (limited to 'drivers/net/wireless/virt_wifi.c')
| -rw-r--r-- | drivers/net/wireless/virt_wifi.c | 697 |
1 files changed, 697 insertions, 0 deletions
diff --git a/drivers/net/wireless/virt_wifi.c b/drivers/net/wireless/virt_wifi.c new file mode 100644 index 000000000..514f2c112 --- /dev/null +++ b/drivers/net/wireless/virt_wifi.c @@ -0,0 +1,697 @@ +// SPDX-License-Identifier: GPL-2.0 +/* drivers/net/wireless/virt_wifi.c + * + * A fake implementation of cfg80211_ops that can be tacked on to an ethernet + * net_device to make it appear as a wireless connection. + * + * Copyright (C) 2018 Google, Inc. + * + * Author: schuffelen@google.com + */ + +#include <net/cfg80211.h> +#include <net/rtnetlink.h> +#include <linux/etherdevice.h> +#include <linux/math64.h> +#include <linux/module.h> + +static struct wiphy *common_wiphy; + +struct virt_wifi_wiphy_priv { + struct delayed_work scan_result; + struct cfg80211_scan_request *scan_request; + bool being_deleted; +}; + +static struct ieee80211_channel channel_2ghz = { + .band = NL80211_BAND_2GHZ, + .center_freq = 2432, + .hw_value = 2432, + .max_power = 20, +}; + +static struct ieee80211_rate bitrates_2ghz[] = { + { .bitrate = 10 }, + { .bitrate = 20 }, + { .bitrate = 55 }, + { .bitrate = 110 }, + { .bitrate = 60 }, + { .bitrate = 120 }, + { .bitrate = 240 }, +}; + +static struct ieee80211_supported_band band_2ghz = { + .channels = &channel_2ghz, + .bitrates = bitrates_2ghz, + .band = NL80211_BAND_2GHZ, + .n_channels = 1, + .n_bitrates = ARRAY_SIZE(bitrates_2ghz), + .ht_cap = { + .ht_supported = true, + .cap = IEEE80211_HT_CAP_SUP_WIDTH_20_40 | + IEEE80211_HT_CAP_GRN_FLD | + IEEE80211_HT_CAP_SGI_20 | + IEEE80211_HT_CAP_SGI_40 | + IEEE80211_HT_CAP_DSSSCCK40, + .ampdu_factor = 0x3, + .ampdu_density = 0x6, + .mcs = { + .rx_mask = {0xff, 0xff}, + .tx_params = IEEE80211_HT_MCS_TX_DEFINED, + }, + }, +}; + +static struct ieee80211_channel channel_5ghz = { + .band = NL80211_BAND_5GHZ, + .center_freq = 5240, + .hw_value = 5240, + .max_power = 20, +}; + +static struct ieee80211_rate bitrates_5ghz[] = { + { .bitrate = 60 }, + { .bitrate = 120 }, + { .bitrate = 240 }, +}; + +#define RX_MCS_MAP (IEEE80211_VHT_MCS_SUPPORT_0_9 << 0 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 2 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 4 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 6 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 8 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 10 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 12 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 14) + +#define TX_MCS_MAP (IEEE80211_VHT_MCS_SUPPORT_0_9 << 0 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 2 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 4 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 6 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 8 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 10 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 12 | \ + IEEE80211_VHT_MCS_SUPPORT_0_9 << 14) + +static struct ieee80211_supported_band band_5ghz = { + .channels = &channel_5ghz, + .bitrates = bitrates_5ghz, + .band = NL80211_BAND_5GHZ, + .n_channels = 1, + .n_bitrates = ARRAY_SIZE(bitrates_5ghz), + .ht_cap = { + .ht_supported = true, + .cap = IEEE80211_HT_CAP_SUP_WIDTH_20_40 | + IEEE80211_HT_CAP_GRN_FLD | + IEEE80211_HT_CAP_SGI_20 | + IEEE80211_HT_CAP_SGI_40 | + IEEE80211_HT_CAP_DSSSCCK40, + .ampdu_factor = 0x3, + .ampdu_density = 0x6, + .mcs = { + .rx_mask = {0xff, 0xff}, + .tx_params = IEEE80211_HT_MCS_TX_DEFINED, + }, + }, + .vht_cap = { + .vht_supported = true, + .cap = IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454 | + IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ | + IEEE80211_VHT_CAP_RXLDPC | + IEEE80211_VHT_CAP_SHORT_GI_80 | + IEEE80211_VHT_CAP_SHORT_GI_160 | + IEEE80211_VHT_CAP_TXSTBC | + IEEE80211_VHT_CAP_RXSTBC_1 | + IEEE80211_VHT_CAP_RXSTBC_2 | + IEEE80211_VHT_CAP_RXSTBC_3 | + IEEE80211_VHT_CAP_RXSTBC_4 | + IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK, + .vht_mcs = { + .rx_mcs_map = cpu_to_le16(RX_MCS_MAP), + .tx_mcs_map = cpu_to_le16(TX_MCS_MAP), + } + }, +}; + +/* Assigned at module init. Guaranteed locally-administered and unicast. */ +static u8 fake_router_bssid[ETH_ALEN] __ro_after_init = {}; + +static void virt_wifi_inform_bss(struct wiphy *wiphy) +{ + u64 tsf = div_u64(ktime_get_boottime_ns(), 1000); + struct cfg80211_bss *informed_bss; + static const struct { + u8 tag; + u8 len; + u8 ssid[8]; + } __packed ssid = { + .tag = WLAN_EID_SSID, + .len = 8, + .ssid = "VirtWifi", + }; + + informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz, + CFG80211_BSS_FTYPE_PRESP, + fake_router_bssid, tsf, + WLAN_CAPABILITY_ESS, 0, + (void *)&ssid, sizeof(ssid), + DBM_TO_MBM(-50), GFP_KERNEL); + cfg80211_put_bss(wiphy, informed_bss); +} + +/* Called with the rtnl lock held. */ +static int virt_wifi_scan(struct wiphy *wiphy, + struct cfg80211_scan_request *request) +{ + struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy); + + wiphy_debug(wiphy, "scan\n"); + + if (priv->scan_request || priv->being_deleted) + return -EBUSY; + + priv->scan_request = request; + schedule_delayed_work(&priv->scan_result, HZ * 2); + + return 0; +} + +/* Acquires and releases the rdev BSS lock. */ +static void virt_wifi_scan_result(struct work_struct *work) +{ + struct virt_wifi_wiphy_priv *priv = + container_of(work, struct virt_wifi_wiphy_priv, + scan_result.work); + struct wiphy *wiphy = priv_to_wiphy(priv); + struct cfg80211_scan_info scan_info = { .aborted = false }; + + virt_wifi_inform_bss(wiphy); + + /* Schedules work which acquires and releases the rtnl lock. */ + cfg80211_scan_done(priv->scan_request, &scan_info); + priv->scan_request = NULL; +} + +/* May acquire and release the rdev BSS lock. */ +static void virt_wifi_cancel_scan(struct wiphy *wiphy) +{ + struct virt_wifi_wiphy_priv *priv = wiphy_priv(wiphy); + + cancel_delayed_work_sync(&priv->scan_result); + /* Clean up dangling callbacks if necessary. */ + if (priv->scan_request) { + struct cfg80211_scan_info scan_info = { .aborted = true }; + /* Schedules work which acquires and releases the rtnl lock. */ + cfg80211_scan_done(priv->scan_request, &scan_info); + priv->scan_request = NULL; + } +} + +struct virt_wifi_netdev_priv { + struct delayed_work connect; + struct net_device *lowerdev; + struct net_device *upperdev; + u32 tx_packets; + u32 tx_failed; + u8 connect_requested_bss[ETH_ALEN]; + bool is_up; + bool is_connected; + bool being_deleted; +}; + +/* Called with the rtnl lock held. */ +static int virt_wifi_connect(struct wiphy *wiphy, struct net_device *netdev, + struct cfg80211_connect_params *sme) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(netdev); + bool could_schedule; + + if (priv->being_deleted || !priv->is_up) + return -EBUSY; + + could_schedule = schedule_delayed_work(&priv->connect, HZ * 2); + if (!could_schedule) + return -EBUSY; + + if (sme->bssid) { + ether_addr_copy(priv->connect_requested_bss, sme->bssid); + } else { + virt_wifi_inform_bss(wiphy); + eth_zero_addr(priv->connect_requested_bss); + } + + wiphy_debug(wiphy, "connect\n"); + + return 0; +} + +/* Acquires and releases the rdev event lock. */ +static void virt_wifi_connect_complete(struct work_struct *work) +{ + struct virt_wifi_netdev_priv *priv = + container_of(work, struct virt_wifi_netdev_priv, connect.work); + u8 *requested_bss = priv->connect_requested_bss; + bool right_addr = ether_addr_equal(requested_bss, fake_router_bssid); + u16 status = WLAN_STATUS_SUCCESS; + + if (is_zero_ether_addr(requested_bss)) + requested_bss = NULL; + + if (!priv->is_up || (requested_bss && !right_addr)) + status = WLAN_STATUS_UNSPECIFIED_FAILURE; + else + priv->is_connected = true; + + /* Schedules an event that acquires the rtnl lock. */ + cfg80211_connect_result(priv->upperdev, requested_bss, NULL, 0, NULL, 0, + status, GFP_KERNEL); + netif_carrier_on(priv->upperdev); +} + +/* May acquire and release the rdev event lock. */ +static void virt_wifi_cancel_connect(struct net_device *netdev) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(netdev); + + /* If there is work pending, clean up dangling callbacks. */ + if (cancel_delayed_work_sync(&priv->connect)) { + /* Schedules an event that acquires the rtnl lock. */ + cfg80211_connect_result(priv->upperdev, + priv->connect_requested_bss, NULL, 0, + NULL, 0, + WLAN_STATUS_UNSPECIFIED_FAILURE, + GFP_KERNEL); + } +} + +/* Called with the rtnl lock held. Acquires the rdev event lock. */ +static int virt_wifi_disconnect(struct wiphy *wiphy, struct net_device *netdev, + u16 reason_code) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(netdev); + + if (priv->being_deleted) + return -EBUSY; + + wiphy_debug(wiphy, "disconnect\n"); + virt_wifi_cancel_connect(netdev); + + cfg80211_disconnected(netdev, reason_code, NULL, 0, true, GFP_KERNEL); + priv->is_connected = false; + netif_carrier_off(netdev); + + return 0; +} + +/* Called with the rtnl lock held. */ +static int virt_wifi_get_station(struct wiphy *wiphy, struct net_device *dev, + const u8 *mac, struct station_info *sinfo) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + wiphy_debug(wiphy, "get_station\n"); + + if (!priv->is_connected || !ether_addr_equal(mac, fake_router_bssid)) + return -ENOENT; + + sinfo->filled = BIT_ULL(NL80211_STA_INFO_TX_PACKETS) | + BIT_ULL(NL80211_STA_INFO_TX_FAILED) | + BIT_ULL(NL80211_STA_INFO_SIGNAL) | + BIT_ULL(NL80211_STA_INFO_TX_BITRATE); + sinfo->tx_packets = priv->tx_packets; + sinfo->tx_failed = priv->tx_failed; + /* For CFG80211_SIGNAL_TYPE_MBM, value is expressed in _dBm_ */ + sinfo->signal = -50; + sinfo->txrate = (struct rate_info) { + .legacy = 10, /* units are 100kbit/s */ + }; + return 0; +} + +/* Called with the rtnl lock held. */ +static int virt_wifi_dump_station(struct wiphy *wiphy, struct net_device *dev, + int idx, u8 *mac, struct station_info *sinfo) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + wiphy_debug(wiphy, "dump_station\n"); + + if (idx != 0 || !priv->is_connected) + return -ENOENT; + + ether_addr_copy(mac, fake_router_bssid); + return virt_wifi_get_station(wiphy, dev, fake_router_bssid, sinfo); +} + +static const struct cfg80211_ops virt_wifi_cfg80211_ops = { + .scan = virt_wifi_scan, + + .connect = virt_wifi_connect, + .disconnect = virt_wifi_disconnect, + + .get_station = virt_wifi_get_station, + .dump_station = virt_wifi_dump_station, +}; + +/* Acquires and releases the rtnl lock. */ +static struct wiphy *virt_wifi_make_wiphy(void) +{ + struct wiphy *wiphy; + struct virt_wifi_wiphy_priv *priv; + int err; + + wiphy = wiphy_new(&virt_wifi_cfg80211_ops, sizeof(*priv)); + + if (!wiphy) + return NULL; + + wiphy->max_scan_ssids = 4; + wiphy->max_scan_ie_len = 1000; + wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM; + + wiphy->bands[NL80211_BAND_2GHZ] = &band_2ghz; + wiphy->bands[NL80211_BAND_5GHZ] = &band_5ghz; + wiphy->bands[NL80211_BAND_60GHZ] = NULL; + + wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION); + + priv = wiphy_priv(wiphy); + priv->being_deleted = false; + priv->scan_request = NULL; + INIT_DELAYED_WORK(&priv->scan_result, virt_wifi_scan_result); + + err = wiphy_register(wiphy); + if (err < 0) { + wiphy_free(wiphy); + return NULL; + } + + return wiphy; +} + +/* Acquires and releases the rtnl lock. */ +static void virt_wifi_destroy_wiphy(struct wiphy *wiphy) +{ + struct virt_wifi_wiphy_priv *priv; + + WARN(!wiphy, "%s called with null wiphy", __func__); + if (!wiphy) + return; + + priv = wiphy_priv(wiphy); + priv->being_deleted = true; + virt_wifi_cancel_scan(wiphy); + + if (wiphy->registered) + wiphy_unregister(wiphy); + wiphy_free(wiphy); +} + +/* Enters and exits a RCU-bh critical section. */ +static netdev_tx_t virt_wifi_start_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + priv->tx_packets++; + if (!priv->is_connected) { + priv->tx_failed++; + return NET_XMIT_DROP; + } + + skb->dev = priv->lowerdev; + return dev_queue_xmit(skb); +} + +/* Called with rtnl lock held. */ +static int virt_wifi_net_device_open(struct net_device *dev) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + priv->is_up = true; + return 0; +} + +/* Called with rtnl lock held. */ +static int virt_wifi_net_device_stop(struct net_device *dev) +{ + struct virt_wifi_netdev_priv *n_priv = netdev_priv(dev); + + n_priv->is_up = false; + + if (!dev->ieee80211_ptr) + return 0; + + virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy); + virt_wifi_cancel_connect(dev); + netif_carrier_off(dev); + + return 0; +} + +static int virt_wifi_net_device_get_iflink(const struct net_device *dev) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + return priv->lowerdev->ifindex; +} + +static const struct net_device_ops virt_wifi_ops = { + .ndo_start_xmit = virt_wifi_start_xmit, + .ndo_open = virt_wifi_net_device_open, + .ndo_stop = virt_wifi_net_device_stop, + .ndo_get_iflink = virt_wifi_net_device_get_iflink, +}; + +/* Invoked as part of rtnl lock release. */ +static void virt_wifi_net_device_destructor(struct net_device *dev) +{ + /* Delayed past dellink to allow nl80211 to react to the device being + * deleted. + */ + kfree(dev->ieee80211_ptr); + dev->ieee80211_ptr = NULL; +} + +/* No lock interaction. */ +static void virt_wifi_setup(struct net_device *dev) +{ + ether_setup(dev); + dev->netdev_ops = &virt_wifi_ops; + dev->needs_free_netdev = true; +} + +/* Called in a RCU read critical section from netif_receive_skb */ +static rx_handler_result_t virt_wifi_rx_handler(struct sk_buff **pskb) +{ + struct sk_buff *skb = *pskb; + struct virt_wifi_netdev_priv *priv = + rcu_dereference(skb->dev->rx_handler_data); + + if (!priv->is_connected) + return RX_HANDLER_PASS; + + /* GFP_ATOMIC because this is a packet interrupt handler. */ + skb = skb_share_check(skb, GFP_ATOMIC); + if (!skb) { + dev_err(&priv->upperdev->dev, "can't skb_share_check\n"); + return RX_HANDLER_CONSUMED; + } + + *pskb = skb; + skb->dev = priv->upperdev; + skb->pkt_type = PACKET_HOST; + return RX_HANDLER_ANOTHER; +} + +/* Called with rtnl lock held. */ +static int virt_wifi_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + int err; + + if (!tb[IFLA_LINK]) + return -EINVAL; + + netif_carrier_off(dev); + + priv->upperdev = dev; + priv->lowerdev = __dev_get_by_index(src_net, + nla_get_u32(tb[IFLA_LINK])); + + if (!priv->lowerdev) + return -ENODEV; + if (!tb[IFLA_MTU]) + dev->mtu = priv->lowerdev->mtu; + else if (dev->mtu > priv->lowerdev->mtu) + return -EINVAL; + + err = netdev_rx_handler_register(priv->lowerdev, virt_wifi_rx_handler, + priv); + if (err) { + dev_err(&priv->lowerdev->dev, + "can't netdev_rx_handler_register: %d\n", err); + return err; + } + + eth_hw_addr_inherit(dev, priv->lowerdev); + netif_stacked_transfer_operstate(priv->lowerdev, dev); + + SET_NETDEV_DEV(dev, &priv->lowerdev->dev); + dev->ieee80211_ptr = kzalloc(sizeof(*dev->ieee80211_ptr), GFP_KERNEL); + + if (!dev->ieee80211_ptr) { + err = -ENOMEM; + goto remove_handler; + } + + dev->ieee80211_ptr->iftype = NL80211_IFTYPE_STATION; + dev->ieee80211_ptr->wiphy = common_wiphy; + + err = register_netdevice(dev); + if (err) { + dev_err(&priv->lowerdev->dev, "can't register_netdevice: %d\n", + err); + goto free_wireless_dev; + } + + err = netdev_upper_dev_link(priv->lowerdev, dev, extack); + if (err) { + dev_err(&priv->lowerdev->dev, "can't netdev_upper_dev_link: %d\n", + err); + goto unregister_netdev; + } + + dev->priv_destructor = virt_wifi_net_device_destructor; + priv->being_deleted = false; + priv->is_connected = false; + priv->is_up = false; + INIT_DELAYED_WORK(&priv->connect, virt_wifi_connect_complete); + __module_get(THIS_MODULE); + + return 0; +unregister_netdev: + unregister_netdevice(dev); +free_wireless_dev: + kfree(dev->ieee80211_ptr); + dev->ieee80211_ptr = NULL; +remove_handler: + netdev_rx_handler_unregister(priv->lowerdev); + + return err; +} + +/* Called with rtnl lock held. */ +static void virt_wifi_dellink(struct net_device *dev, + struct list_head *head) +{ + struct virt_wifi_netdev_priv *priv = netdev_priv(dev); + + if (dev->ieee80211_ptr) + virt_wifi_cancel_scan(dev->ieee80211_ptr->wiphy); + + priv->being_deleted = true; + virt_wifi_cancel_connect(dev); + netif_carrier_off(dev); + + netdev_rx_handler_unregister(priv->lowerdev); + netdev_upper_dev_unlink(priv->lowerdev, dev); + + unregister_netdevice_queue(dev, head); + module_put(THIS_MODULE); + + /* Deleting the wiphy is handled in the module destructor. */ +} + +static struct rtnl_link_ops virt_wifi_link_ops = { + .kind = "virt_wifi", + .setup = virt_wifi_setup, + .newlink = virt_wifi_newlink, + .dellink = virt_wifi_dellink, + .priv_size = sizeof(struct virt_wifi_netdev_priv), +}; + +static bool netif_is_virt_wifi_dev(const struct net_device *dev) +{ + return rcu_access_pointer(dev->rx_handler) == virt_wifi_rx_handler; +} + +static int virt_wifi_event(struct notifier_block *this, unsigned long event, + void *ptr) +{ + struct net_device *lower_dev = netdev_notifier_info_to_dev(ptr); + struct virt_wifi_netdev_priv *priv; + struct net_device *upper_dev; + LIST_HEAD(list_kill); + + if (!netif_is_virt_wifi_dev(lower_dev)) + return NOTIFY_DONE; + + switch (event) { + case NETDEV_UNREGISTER: + priv = rtnl_dereference(lower_dev->rx_handler_data); + if (!priv) + return NOTIFY_DONE; + + upper_dev = priv->upperdev; + + upper_dev->rtnl_link_ops->dellink(upper_dev, &list_kill); + unregister_netdevice_many(&list_kill); + break; + } + + return NOTIFY_DONE; +} + +static struct notifier_block virt_wifi_notifier = { + .notifier_call = virt_wifi_event, +}; + +/* Acquires and releases the rtnl lock. */ +static int __init virt_wifi_init_module(void) +{ + int err; + + /* Guaranteed to be locallly-administered and not multicast. */ + eth_random_addr(fake_router_bssid); + + err = register_netdevice_notifier(&virt_wifi_notifier); + if (err) + return err; + + err = -ENOMEM; + common_wiphy = virt_wifi_make_wiphy(); + if (!common_wiphy) + goto notifier; + + err = rtnl_link_register(&virt_wifi_link_ops); + if (err) + goto destroy_wiphy; + + return 0; + +destroy_wiphy: + virt_wifi_destroy_wiphy(common_wiphy); +notifier: + unregister_netdevice_notifier(&virt_wifi_notifier); + return err; +} + +/* Acquires and releases the rtnl lock. */ +static void __exit virt_wifi_cleanup_module(void) +{ + /* Will delete any devices that depend on the wiphy. */ + rtnl_link_unregister(&virt_wifi_link_ops); + virt_wifi_destroy_wiphy(common_wiphy); + unregister_netdevice_notifier(&virt_wifi_notifier); +} + +module_init(virt_wifi_init_module); +module_exit(virt_wifi_cleanup_module); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Cody Schuffelen <schuffelen@google.com>"); +MODULE_DESCRIPTION("Driver for a wireless wrapper of ethernet devices"); +MODULE_ALIAS_RTNL_LINK("virt_wifi"); 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