* [PATCH v6 3/4] cfg80211: configure multicast to unicast for AP interfaces
2016-10-10 17:12 [PATCH v6 1/4] mac80211: remove unnecessary num_mcast_sta user Michael Braun
[not found] ` <1476119543-24509-1-git-send-email-michael-dev-1SGGS//iJ+Y38rf8aCqVIw@public.gmane.org>
@ 2016-10-10 17:12 ` Michael Braun
2016-10-27 12:20 ` Johannes Berg
2016-10-10 17:12 ` [PATCH v6 4/4] mac80211: multicast to unicast conversion Michael Braun
2 siblings, 1 reply; 7+ messages in thread
From: Michael Braun @ 2016-10-10 17:12 UTC (permalink / raw)
To: johannes; +Cc: Michael Braun, linux-wireless, projekt-wlan, netdev
This add a userspace toggle to configure multicast to unicast.
Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
--
v6:
- clarify documentation
- fix policy for NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED
---
include/net/cfg80211.h | 6 ++++++
include/uapi/linux/nl80211.h | 18 ++++++++++++++++++
net/wireless/nl80211.c | 36 ++++++++++++++++++++++++++++++++++++
net/wireless/rdev-ops.h | 12 ++++++++++++
net/wireless/trace.h | 19 +++++++++++++++++++
5 files changed, 91 insertions(+)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7ce6223..7b0941d 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2460,6 +2460,8 @@ struct cfg80211_qos_map {
*
* @set_wds_peer: set the WDS peer for a WDS interface
*
+ * @set_multicast_to_unicast: configure multicast to unicast conversion for BSS
+ *
* @rfkill_poll: polls the hw rfkill line, use cfg80211 reporting
* functions to adjust rfkill hw state
*
@@ -2722,6 +2724,10 @@ struct cfg80211_ops {
int (*set_wds_peer)(struct wiphy *wiphy, struct net_device *dev,
const u8 *addr);
+ int (*set_multicast_to_unicast)(struct wiphy *wiphy,
+ struct net_device *dev,
+ const bool enabled);
+
void (*rfkill_poll)(struct wiphy *wiphy);
#ifdef CONFIG_NL80211_TESTMODE
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 2206941..327bbb8 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -599,6 +599,17 @@
*
* @NL80211_CMD_SET_WDS_PEER: Set the MAC address of the peer on a WDS interface.
*
+ * @NL80211_CMD_SET_MULTICAST_TO_UNICAST: Configure if this AP should perform
+ * multicast to unicast conversion. When enabled, all multicast packets
+ * with ethertype ARP, IPv4 or IPv6 (possibly within an 802.1q header)
+ * will be sent out to each station once with the destination (multicast)
+ * mac address replaced by the stations mac address.
+ * This can only be toggled per BSS. Configure this on an interface of
+ * type %NL80211_IFTYPE_AP. It applies to all its vlans interfaces
+ * (%NL80211_IFTYPE_AP_VLAN), except for those in 4addr (WDS) mode.
+ * If %NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED is not present with this
+ * command, the feature is disabled.
+ *
* @NL80211_CMD_JOIN_MESH: Join a mesh. The mesh ID must be given, and initial
* mesh config parameters may be given.
* @NL80211_CMD_LEAVE_MESH: Leave the mesh network -- no special arguments, the
@@ -1026,6 +1037,8 @@ enum nl80211_commands {
NL80211_CMD_ABORT_SCAN,
+ NL80211_CMD_SET_MULTICAST_TO_UNICAST,
+
/* add new commands above here */
/* used to define NL80211_CMD_MAX below */
@@ -1867,6 +1880,9 @@ enum nl80211_commands {
* @NL80211_ATTR_MESH_PEER_AID: Association ID for the mesh peer (u16). This is
* used to pull the stored data for mesh peer in power save state.
*
+ * @NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED: Multicast packets should be
+ * send out as unicast to all stations.
+ *
* @NUM_NL80211_ATTR: total number of nl80211_attrs available
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2261,6 +2277,8 @@ enum nl80211_attrs {
NL80211_ATTR_MESH_PEER_AID,
+ NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index f02653a..3684e28 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -409,6 +409,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
.len = VHT_MUMIMO_GROUPS_DATA_LEN
},
[NL80211_ATTR_MU_MIMO_FOLLOW_MAC_ADDR] = { .len = ETH_ALEN },
+ [NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED] = { .type = NLA_FLAG, },
};
/* policy for the key attributes */
@@ -1538,6 +1539,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
goto nla_put_failure;
}
CMD(set_wds_peer, SET_WDS_PEER);
+ CMD(set_multicast_to_unicast, SET_MULTICAST_TO_UNICAST);
if (rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_TDLS) {
CMD(tdls_mgmt, TDLS_MGMT);
CMD(tdls_oper, TDLS_OPER);
@@ -2164,6 +2166,32 @@ static int nl80211_set_wds_peer(struct sk_buff *skb, struct genl_info *info)
return rdev_set_wds_peer(rdev, dev, bssid);
}
+static int nl80211_set_multicast_to_unicast(struct sk_buff *skb,
+ struct genl_info *info)
+{
+ struct cfg80211_registered_device *rdev = info->user_ptr[0];
+ struct net_device *dev = info->user_ptr[1];
+ struct wireless_dev *wdev = dev->ieee80211_ptr;
+ const struct nlattr *nla;
+ bool enabled;
+
+ if (!info->attrs[NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED])
+ return -EINVAL;
+
+ if (netif_running(dev))
+ return -EBUSY;
+
+ if (!rdev->ops->set_multicast_to_unicast)
+ return -EOPNOTSUPP;
+
+ if (wdev->iftype != NL80211_IFTYPE_AP)
+ return -EOPNOTSUPP;
+
+ nla = info->attrs[NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED];
+ enabled = nla_get_flag(nla);
+ return rdev_set_multicast_to_unicast(rdev, dev, enabled);
+}
+
static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
{
struct cfg80211_registered_device *rdev;
@@ -11574,6 +11602,14 @@ static const struct genl_ops nl80211_ops[] = {
NL80211_FLAG_NEED_RTNL,
},
{
+ .cmd = NL80211_CMD_SET_MULTICAST_TO_UNICAST,
+ .doit = nl80211_set_multicast_to_unicast,
+ .policy = nl80211_policy,
+ .flags = GENL_UNS_ADMIN_PERM,
+ .internal_flags = NL80211_FLAG_NEED_NETDEV |
+ NL80211_FLAG_NEED_RTNL,
+ },
+ {
.cmd = NL80211_CMD_JOIN_MESH,
.doit = nl80211_join_mesh,
.policy = nl80211_policy,
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 85ff30b..7d93c3d 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -562,6 +562,18 @@ static inline int rdev_set_wds_peer(struct cfg80211_registered_device *rdev,
return ret;
}
+static inline int
+rdev_set_multicast_to_unicast(struct cfg80211_registered_device *rdev,
+ struct net_device *dev,
+ const bool enabled)
+{
+ int ret;
+ trace_rdev_set_multicast_to_unicast(&rdev->wiphy, dev, enabled);
+ ret = rdev->ops->set_multicast_to_unicast(&rdev->wiphy, dev, enabled);
+ trace_rdev_return_int(&rdev->wiphy, ret);
+ return ret;
+}
+
static inline void rdev_rfkill_poll(struct cfg80211_registered_device *rdev)
{
trace_rdev_rfkill_poll(&rdev->wiphy);
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 72b5255..8c9aa57 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2940,6 +2940,25 @@ DEFINE_EVENT(wiphy_wdev_evt, rdev_abort_scan,
TP_PROTO(struct wiphy *wiphy, struct wireless_dev *wdev),
TP_ARGS(wiphy, wdev)
);
+
+TRACE_EVENT(rdev_set_multicast_to_unicast,
+ TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+ const bool enabled),
+ TP_ARGS(wiphy, netdev, enabled),
+ TP_STRUCT__entry(
+ WIPHY_ENTRY
+ NETDEV_ENTRY
+ __field(bool, enabled)
+ ),
+ TP_fast_assign(
+ WIPHY_ASSIGN;
+ NETDEV_ASSIGN;
+ __entry->enabled = enabled;
+ ),
+ TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", unicast: %s",
+ WIPHY_PR_ARG, NETDEV_PR_ARG,
+ BOOL_TO_STR(__entry->enabled))
+);
#endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */
#undef TRACE_INCLUDE_PATH
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 4/4] mac80211: multicast to unicast conversion
2016-10-10 17:12 [PATCH v6 1/4] mac80211: remove unnecessary num_mcast_sta user Michael Braun
[not found] ` <1476119543-24509-1-git-send-email-michael-dev-1SGGS//iJ+Y38rf8aCqVIw@public.gmane.org>
2016-10-10 17:12 ` [PATCH v6 3/4] cfg80211: configure multicast to unicast for AP interfaces Michael Braun
@ 2016-10-10 17:12 ` Michael Braun
[not found] ` <1476119543-24509-4-git-send-email-michael-dev-1SGGS//iJ+Y38rf8aCqVIw@public.gmane.org>
2 siblings, 1 reply; 7+ messages in thread
From: Michael Braun @ 2016-10-10 17:12 UTC (permalink / raw)
To: johannes; +Cc: Michael Braun, linux-wireless, projekt-wlan, netdev
This patch adds support for sending multicast data packets with ARP, IPv4
and IPv6 payload (possible 802.1q tagged) as 802.11 unicast frames to all
stations.
IEEE 802.11 multicast has well known issues, among them:
1. packets are not acked and hence not retransmitted, resulting in
decreased reliablity
2. packets are send at low rate, increasing time required on air
When used with AP_VLAN, there is another disadvantage:
3. all stations in the BSS are woken up, regardsless of their AP_VLAN
assignment.
By doing multicast to unicast conversion, all three issus are solved.
IEEE802.11-2012 proposes directed multicast service (DMS) using A-MSDU
frames and a station initiated control protocol. It has the advantage that
the station can recover the destination multicast mac address, but it is
not backward compatible with non QOS stations and does not enable the
administrator of a BSS to force this mode of operation within a BSS.
Additionally, it would require both the ap and the station to implement
the control protocol, which is optional on both ends. Furthermore, I've
seen a few mobile phone stations locally that indicate qos support but
won't complete DHCP if their broadcasts are encapsulated as A-MSDU. Though
they work fine with this series approach.
This patch therefore does not opt to implement DMS but instead just
replicates the packet and changes the destination address. As this works
fine with ARP, IPv4 and IPv6, it is limited to these protocols and normal
802.11 multicast frames are send out for all other payload protocols.
There is a runtime toggle to enable multicast conversion in a per-bss
fashion.
When there is only a single station assigned to the AP_VLAN interface, no
packet replication will occur. 4addr mode of operation is unchanged.
This change opts for iterating all BSS stations for finding the stations
assigned to this AP/AP_VLAN interface, as there currently is no per
AP_VLAN list to iterate and multicast packets are expected to be few.
If needed, such a list could be added later.
Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
--
v5:
- rename bss->unicast to bss->multicast_to_unicast
- access sdata->bss only after checking iftype
v4:
- rename MULTICAST_TO_UNICAST to MULTICAST_TO_UNICAST
v3: fix compile error for trace.h
v2: add nl80211 toggle
rename tx_dnat to change_da
change int to bool unicast
---
net/mac80211/cfg.c | 15 +++++++
net/mac80211/debugfs_netdev.c | 3 ++
net/mac80211/ieee80211_i.h | 1 +
net/mac80211/tx.c | 101 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 120 insertions(+)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1edb017..1db4c3e 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2242,6 +2242,20 @@ static int ieee80211_set_wds_peer(struct wiphy *wiphy, struct net_device *dev,
return 0;
}
+static int ieee80211_set_multicast_to_unicast(struct wiphy *wiphy,
+ struct net_device *dev,
+ const bool enabled)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+ if (sdata->vif.type != NL80211_IFTYPE_AP)
+ return -1;
+
+ sdata->u.ap.multicast_to_unicast = enabled;
+
+ return 0;
+}
+
static void ieee80211_rfkill_poll(struct wiphy *wiphy)
{
struct ieee80211_local *local = wiphy_priv(wiphy);
@@ -3400,6 +3414,7 @@ const struct cfg80211_ops mac80211_config_ops = {
.set_tx_power = ieee80211_set_tx_power,
.get_tx_power = ieee80211_get_tx_power,
.set_wds_peer = ieee80211_set_wds_peer,
+ .set_multicast_to_unicast = ieee80211_set_multicast_to_unicast,
.rfkill_poll = ieee80211_rfkill_poll,
CFG80211_TESTMODE_CMD(ieee80211_testmode_cmd)
CFG80211_TESTMODE_DUMP(ieee80211_testmode_dump)
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index ed7bff4..509c6c3 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -487,6 +487,8 @@ static ssize_t ieee80211_if_fmt_num_buffered_multicast(
}
IEEE80211_IF_FILE_R(num_buffered_multicast);
+IEEE80211_IF_FILE(multicast_to_unicast, u.ap.multicast_to_unicast, HEX);
+
/* IBSS attributes */
static ssize_t ieee80211_if_fmt_tsf(
const struct ieee80211_sub_if_data *sdata, char *buf, int buflen)
@@ -642,6 +644,7 @@ static void add_ap_files(struct ieee80211_sub_if_data *sdata)
DEBUGFS_ADD(dtim_count);
DEBUGFS_ADD(num_buffered_multicast);
DEBUGFS_ADD_MODE(tkip_mic_test, 0200);
+ DEBUGFS_ADD_MODE(multicast_to_unicast, 0600);
}
static void add_vlan_files(struct ieee80211_sub_if_data *sdata)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 70c0963..84374ed 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -293,6 +293,7 @@ struct ieee80211_if_ap {
driver_smps_mode; /* smps mode request */
struct work_struct request_smps_work;
+ bool multicast_to_unicast;
};
struct ieee80211_if_wds {
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index c3ce86e..142201d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
+#include <linux/if_vlan.h>
#include <linux/etherdevice.h>
#include <linux/bitmap.h>
#include <linux/rcupdate.h>
@@ -1770,6 +1771,102 @@ bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw,
}
EXPORT_SYMBOL(ieee80211_tx_prepare_skb);
+/* rewrite destination mac address */
+static int ieee80211_change_da(struct sk_buff *skb, struct sta_info *sta)
+{
+ struct ethhdr *eth;
+ int err;
+
+ err = skb_ensure_writable(skb, ETH_HLEN);
+ if (unlikely(err))
+ return err;
+
+ eth = (void *)skb->data;
+ ether_addr_copy(eth->h_dest, sta->sta.addr);
+
+ return 0;
+}
+
+/* Check if multicast to unicast conversion is needed and do it.
+ * Returns 1 if skb was freed and should not be send out.
+ */
+static int
+ieee80211_tx_multicast_to_unicast(struct ieee80211_sub_if_data *sdata,
+ struct sk_buff *skb, u32 info_flags)
+{
+ struct ieee80211_local *local = sdata->local;
+ const struct ethhdr *eth = (void *)skb->data;
+ const struct vlan_ethhdr *ethvlan = (void *)skb->data;
+ struct sta_info *sta, *prev = NULL;
+ struct sk_buff *cloned_skb;
+ u16 ethertype;
+
+ /* check if this is a multicast frame */
+ if (!is_multicast_ether_addr(eth->h_dest))
+ return 0;
+
+ /* multicast to unicast conversion only for AP interfaces */
+ switch (sdata->vif.type) {
+ case NL80211_IFTYPE_AP_VLAN:
+ sta = rcu_dereference(sdata->u.vlan.sta);
+ if (sta) /* 4addr */
+ return 0;
+ /* fall through */
+ case NL80211_IFTYPE_AP:
+ /* check runtime toggle for this bss */
+ if (!sdata->bss->multicast_to_unicast)
+ return 0;
+ break;
+ default:
+ return 0;
+ }
+
+ /* info_flags would not get preserved, used only by TLDS */
+ if (info_flags)
+ return 0;
+
+ /* multicast to unicast conversion only for some payload */
+ ethertype = ntohs(eth->h_proto);
+ if (ethertype == ETH_P_8021Q && skb->len >= VLAN_ETH_HLEN)
+ ethertype = ntohs(ethvlan->h_vlan_encapsulated_proto);
+ switch (ethertype) {
+ case ETH_P_ARP:
+ case ETH_P_IP:
+ case ETH_P_IPV6:
+ break;
+ default:
+ return 0;
+ }
+
+ /* clone packets and update destination mac */
+ list_for_each_entry_rcu(sta, &local->sta_list, list) {
+ if (sdata != sta->sdata)
+ continue;
+ if (unlikely(!ether_addr_equal(eth->h_source, sta->sta.addr)))
+ /* do not send back to source */
+ continue;
+ if (!prev) {
+ prev = sta;
+ continue;
+ }
+ cloned_skb = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(ieee80211_change_da(cloned_skb, prev))) {
+ dev_kfree_skb(cloned_skb);
+ continue;
+ }
+ __ieee80211_subif_start_xmit(cloned_skb, cloned_skb->dev, 0);
+ prev = sta;
+ }
+
+ if (likely(prev)) {
+ ieee80211_change_da(skb, prev);
+ return 0;
+ }
+
+ /* no STA connected, drop */
+ return 1;
+}
+
/*
* Returns false if the frame couldn't be transmitted but was queued instead.
*/
@@ -3353,6 +3450,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
rcu_read_lock();
+ /* AP multicast to unicast conversion */
+ if (ieee80211_tx_multicast_to_unicast(sdata, skb, info_flags))
+ goto out_free;
+
if (ieee80211_lookup_ra_sta(sdata, skb, &sta))
goto out_free;
--
2.1.4
^ permalink raw reply related [flat|nested] 7+ messages in thread