From: Johannes Berg <johannes.berg@xxxxxxxxx>
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 <johannes.berg@xxxxxxxxx>
---
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
