From: Johannes Berg <[email protected]> Add the necessary hooks for running monitor filter programs in mac80211's RX path, before a frame is handed off to a monitor interface. If the frame isn't accepted then this will save the overhead of creating a new SKB and building the radiotap header.
Signed-off-by: Johannes Berg <[email protected]> --- net/mac80211/Kconfig | 1 + net/mac80211/cfg.c | 15 +++++++++++++++ net/mac80211/ieee80211_i.h | 6 ++++++ net/mac80211/iface.c | 11 ++++++++++- net/mac80211/main.c | 3 +++ net/mac80211/rx.c | 33 +++++++++++++++++++++++++++++++-- 6 files changed, 66 insertions(+), 3 deletions(-) diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig index 76e30f4797fb..080e0c705c72 100644 --- a/net/mac80211/Kconfig +++ b/net/mac80211/Kconfig @@ -8,6 +8,7 @@ config MAC80211 select CRYPTO_GCM select CRYPTO_CMAC select CRC32 + select WANT_BPF_WIFIMON ---help--- This option enables the hardware independent IEEE 802.11 networking stack. diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 7af648e95bc6..5d427ed8b6c8 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -107,6 +107,21 @@ static int ieee80211_set_mon_options(struct ieee80211_sub_if_data *sdata, } } +#ifdef CONFIG_BPF_WIFIMON + if (params->filter) { + struct bpf_prog *old = rtnl_dereference(sdata->u.mntr.filter); + + if (IS_ERR(params->filter)) + RCU_INIT_POINTER(sdata->u.mntr.filter, NULL); + else + rcu_assign_pointer(sdata->u.mntr.filter, + params->filter); + + if (old) + bpf_prog_put(old); + } +#endif + return 0; } diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index cf6d5abb65a3..fb0592e0f7b3 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -27,6 +27,8 @@ #include <linux/leds.h> #include <linux/idr.h> #include <linux/rhashtable.h> +#include <linux/filter.h> +#include <linux/bpf.h> #include <net/ieee80211_radiotap.h> #include <net/cfg80211.h> #include <net/mac80211.h> @@ -841,6 +843,10 @@ struct ieee80211_if_mntr { u8 mu_follow_addr[ETH_ALEN] __aligned(2); struct list_head list; + +#ifdef CONFIG_BPF_WIFIMON + struct bpf_prog *filter; +#endif }; /** diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 3bd5b81f5d81..5c25afa6cf77 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -1122,8 +1122,17 @@ static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata) __skb_queue_purge(&sdata->fragments[i].skb_list); sdata->fragment_next = 0; - if (ieee80211_vif_is_mesh(&sdata->vif)) + if (ieee80211_vif_is_mesh(&sdata->vif)) { ieee80211_mesh_teardown_sdata(sdata); + } else if (sdata->vif.type == NL80211_IFTYPE_MONITOR) { +#ifdef CONFIG_BPF_WIFIMON + struct bpf_prog *old = rtnl_dereference(sdata->u.mntr.filter); + + RCU_INIT_POINTER(sdata->u.mntr.filter, NULL); + if (old) + bpf_prog_put(old); +#endif + } } static void ieee80211_uninit(struct net_device *dev) diff --git a/net/mac80211/main.c b/net/mac80211/main.c index ae408a96c407..b7857e710fd5 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -551,6 +551,9 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len, NL80211_FEATURE_FULL_AP_CLIENT_STATE; wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_FILS_STA); + if (IS_ENABLED(CONFIG_BPF_WIFIMON)) + wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_WIFIMON_BPF); + if (!ops->hw_scan) wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN | NL80211_FEATURE_AP_SCAN; diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 50d8f8435830..ea7d56774dd3 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -651,17 +651,39 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_vendor_space); + /* pretend all the monitor info isn't there */ + __pskb_pull(origskb, rtap_vendor_space); + origskb->len -= present_fcs_len; + list_for_each_entry_rcu(sdata, &local->mon_list, u.mntr.list) { + const struct bpf_prog *filter __maybe_unused; bool last_monitor = list_is_last(&sdata->u.mntr.list, &local->mon_list); - if (!monskb) +#ifdef CONFIG_BPF_WIFIMON + filter = rcu_dereference(sdata->u.mntr.filter); + if (filter && !BPF_PROG_RUN(filter, origskb)) + continue; +#endif + + if (!monskb) { + /* stop pretending the monitor info isn't there */ + origskb->len += present_fcs_len; + __skb_push(origskb, rtap_vendor_space); + monskb = ieee80211_make_monitor_skb(local, &origskb, rate, rtap_vendor_space, only_monitor && last_monitor); + if (origskb) { + /* pretend all the monitor info isn't there */ + __pskb_pull(origskb, rtap_vendor_space); + origskb->len -= present_fcs_len; + } + } + if (monskb) { struct sk_buff *skb; @@ -683,13 +705,20 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, break; } - /* this happens if last_monitor was erroneously false */ + /* + * this may happen if filtering, or if the list RCU handling + * got last_monitor erroneously false + */ dev_kfree_skb(monskb); /* ditto */ if (!origskb) return NULL; + /* stop pretending the monitor info isn't there */ + origskb->len += present_fcs_len; + __skb_push(origskb, rtap_vendor_space); + remove_monitor_info(origskb, present_fcs_len, rtap_vendor_space); return origskb; } -- 2.11.0
