mac80211: implement support for 4-address frames for AP and client mode

In some situations it might be useful to run a network with an
Access Point and multiple clients, but with each client bridged
to a network behind it. For this to work, both the client and the
AP need to transmit 4-address frames, containing both source and
destination MAC addresses.
With this patch, you can configure a client to communicate using
only 4-address frames for data traffic.
On the AP side you can enable 4-address frames for individual
clients by isolating them in separate AP VLANs which are configured
in 4-address mode.
Such an AP VLAN will be limited to one client only, and this client
will be used as the destination for all traffic on its interface,
regardless of the destination MAC address in the packet headers.
The advantage of this mode compared to regular WDS mode is that it's
easier to configure and does not require a static list of peer MAC
addresses on any side.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 56319b51d170a55ce897b30ae27460015bef743a..576b86f81d1bc43c0789e9e97641ad1ede60fdce 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -36,6 +36,24 @@ static bool nl80211_type_check(enum nl80211_iftype type)
        }
 }
 
+static bool nl80211_params_check(enum nl80211_iftype type,
+                                struct vif_params *params)
+{
+       if (!nl80211_type_check(type))
+               return false;
+
+       if (params->use_4addr > 0) {
+               switch(type) {
+               case NL80211_IFTYPE_AP_VLAN:
+               case NL80211_IFTYPE_STATION:
+                       break;
+               default:
+                       return false;
+               }
+       }
+       return true;
+}
+
 static int ieee80211_add_iface(struct wiphy *wiphy, char *name,
                               enum nl80211_iftype type, u32 *flags,
                               struct vif_params *params)
@@ -45,7 +63,7 @@ static int ieee80211_add_iface(struct wiphy *wiphy, char *name,
        struct ieee80211_sub_if_data *sdata;
        int err;
 
-       if (!nl80211_type_check(type))
+       if (!nl80211_params_check(type, params))
                return -EINVAL;
 
        err = ieee80211_if_add(local, name, &dev, type, params);
@@ -75,7 +93,7 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
        if (netif_running(dev))
                return -EBUSY;
 
-       if (!nl80211_type_check(type))
+       if (!nl80211_params_check(type, params))
                return -EINVAL;
 
        sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -89,6 +107,9 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
                                            params->mesh_id_len,
                                            params->mesh_id);
 
+       if (params->use_4addr >= 0)
+               sdata->use_4addr = !!params->use_4addr;
+
        if (sdata->vif.type != NL80211_IFTYPE_MONITOR || !flags)
                return 0;
 
@@ -806,6 +827,13 @@ static int ieee80211_change_station(struct wiphy *wiphy,
                        return -EINVAL;
                }
 
+               if (vlansdata->use_4addr) {
+                       if (vlansdata->u.vlan.sta)
+                               return -EBUSY;
+
+                       rcu_assign_pointer(vlansdata->u.vlan.sta, sta);
+               }
+
                sta->sdata = vlansdata;
                ieee80211_send_layer2_update(sta);
        }

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1f4f88a8f80c6cb274ffa26582a6a6b8a38ea7ce..19b0c128d940c446e67e8bf16a27b6da761e6a9e 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -208,6 +208,9 @@ struct ieee80211_if_wds {
 
 struct ieee80211_if_vlan {
        struct list_head list;
+
+       /* used for all tx if the VLAN is configured to 4-addr mode */
+       struct sta_info *sta;
 };
 
 struct mesh_stats {
@@ -457,6 +460,8 @@ struct ieee80211_sub_if_data {
        int force_unicast_rateidx; /* forced TX rateidx for unicast frames */
        int max_ratectrl_rateidx; /* max TX rateidx for rate control */
 
+       bool use_4addr; /* use 4-address frames */
+
        union {
                struct ieee80211_if_ap ap;
                struct ieee80211_if_wds wds;

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 8495161b99b8362f0cf2766a24be1ae9ca63c4d7..1f02b0610e822954d5cdcbe768a0f3ac2824fea0 100644 (file)
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -752,6 +752,7 @@ int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
                ieee80211_mandatory_rates(sdata->local,
                        sdata->local->hw.conf.channel->band);
        sdata->drop_unencrypted = 0;
+       sdata->use_4addr = 0;
 
        return 0;
 }
@@ -819,6 +820,9 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
                                            params->mesh_id_len,
                                            params->mesh_id);
 
+       if (params && params->use_4addr >= 0)
+               sdata->use_4addr = !!params->use_4addr;
+
        mutex_lock(&local->iflist_mtx);
        list_add_tail_rcu(&sdata->list, &local->interfaces);
        mutex_unlock(&local->iflist_mtx);

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 4066570dd4140f91be88209940b93273ea0e698a..76478362a538847aec432cb5115fa75aeb652add 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1181,6 +1181,13 @@ __ieee80211_data_to_8023(struct ieee80211_rx_data *rx)
 {
        struct net_device *dev = rx->dev;
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
+
+       if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->use_4addr &&
+           ieee80211_has_a4(hdr->frame_control))
+               return -1;
+       if (sdata->use_4addr && is_multicast_ether_addr(hdr->addr1))
+               return -1;
 
        return ieee80211_data_to_8023(rx->skb, dev->dev_addr, sdata->vif.type);
 }
@@ -1534,6 +1541,7 @@ ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
 {
        struct net_device *dev = rx->dev;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
+       struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        __le16 fc = hdr->frame_control;
        int err;
 
@@ -1543,6 +1551,14 @@ ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
        if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
                return RX_DROP_MONITOR;
 
+       /*
+        * Allow the cooked monitor interface of an AP to see 4-addr frames so
+        * that a 4-addr station can be detected and moved into a separate VLAN
+        */
+       if (ieee80211_has_a4(hdr->frame_control) &&
+           sdata->vif.type == NL80211_IFTYPE_AP)
+               return RX_DROP_MONITOR;
+
        err = __ieee80211_data_to_8023(rx);
        if (unlikely(err))
                return RX_DROP_UNUSABLE;
@@ -1983,7 +1999,7 @@ static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
 
        switch (sdata->vif.type) {
        case NL80211_IFTYPE_STATION:
-               if (!bssid)
+               if (!bssid && !sdata->use_4addr)
                        return 0;
                if (!multicast &&
                    compare_ether_addr(sdata->dev->dev_addr, hdr->addr1) != 0) {

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index be59456e8a423008ea95794d4d10f1cf1a892af2..396a94806de98fda6bb5ac8ac26d5f1879c15514 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -509,6 +509,9 @@ static void __sta_info_unlink(struct sta_info **sta)
        local->num_sta--;
        local->sta_generation++;
 
+       if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+               rcu_assign_pointer(sdata->u.vlan.sta, NULL);
+
        if (local->ops->sta_notify) {
                if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                        sdata = container_of(sdata->bss,

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index bfaa43e096d228ec015c136dd47176c7b661fd53..2f3345c5f7cfe30b7d539dd9c115960eee84e9a6 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1051,7 +1051,10 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
 
        hdr = (struct ieee80211_hdr *) skb->data;
 
-       tx->sta = sta_info_get(local, hdr->addr1);
+       if ((sdata->vif.type == NL80211_IFTYPE_AP_VLAN) && sdata->use_4addr)
+               tx->sta = rcu_dereference(sdata->u.vlan.sta);
+       if (!tx->sta)
+               tx->sta = sta_info_get(local, hdr->addr1);
 
        if (tx->sta && ieee80211_is_data_qos(hdr->frame_control) &&
            (local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION)) {
@@ -1613,7 +1616,7 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
        const u8 *encaps_data;
        int encaps_len, skip_header_bytes;
        int nh_pos, h_pos;
-       struct sta_info *sta;
+       struct sta_info *sta = NULL;
        u32 sta_flags = 0;
 
        if (unlikely(skb->len < ETH_HLEN)) {
@@ -1630,8 +1633,25 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
        fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
 
        switch (sdata->vif.type) {
-       case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_AP_VLAN:
+               rcu_read_lock();
+               if (sdata->use_4addr)
+                       sta = rcu_dereference(sdata->u.vlan.sta);
+               if (sta) {
+                       fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
+                       /* RA TA DA SA */
+                       memcpy(hdr.addr1, sta->sta.addr, ETH_ALEN);
+                       memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
+                       memcpy(hdr.addr3, skb->data, ETH_ALEN);
+                       memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
+                       hdrlen = 30;
+                       sta_flags = get_sta_flags(sta);
+               }
+               rcu_read_unlock();
+               if (sta)
+                       break;
+               /* fall through */
+       case NL80211_IFTYPE_AP:
                fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
                /* DA BSSID SA */
                memcpy(hdr.addr1, skb->data, ETH_ALEN);
@@ -1705,12 +1725,21 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
                break;
 #endif
        case NL80211_IFTYPE_STATION:
-               fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
-               /* BSSID SA DA */
                memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
-               memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
-               memcpy(hdr.addr3, skb->data, ETH_ALEN);
-               hdrlen = 24;
+               if (sdata->use_4addr && ethertype != ETH_P_PAE) {
+                       fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
+                       /* RA TA DA SA */
+                       memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
+                       memcpy(hdr.addr3, skb->data, ETH_ALEN);
+                       memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
+                       hdrlen = 30;
+               } else {
+                       fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
+                       /* BSSID SA DA */
+                       memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
+                       memcpy(hdr.addr3, skb->data, ETH_ALEN);
+                       hdrlen = 24;
+               }
                break;
        case NL80211_IFTYPE_ADHOC:
                /* DA SA BSSID */

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 3fc2df86278fcf7390c5d2b3cce484a7abb04f4d..5aa39f7cf9b94b4e8d4488b2361a640478f7f138 100644 (file)
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -320,7 +320,9 @@ int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
                break;
        case cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
                if (unlikely(iftype != NL80211_IFTYPE_WDS &&
-                            iftype != NL80211_IFTYPE_MESH_POINT))
+                            iftype != NL80211_IFTYPE_MESH_POINT &&
+                            iftype != NL80211_IFTYPE_AP_VLAN &&
+                            iftype != NL80211_IFTYPE_STATION))
                        return -1;
                if (iftype == NL80211_IFTYPE_MESH_POINT) {
                        struct ieee80211s_hdr *meshdr =