From f14543ee4d0681df1377b976cba704557ba220d3 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 10 Nov 2009 20:10:05 +0100 Subject: 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 Signed-off-by: John W. Linville --- net/wireless/util.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/wireless/util.c') diff --git a/net/wireless/util.c b/net/wireless/util.c index 3fc2df86278f..5aa39f7cf9b9 100644 --- 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 = -- cgit v1.2.3 From 9bc383de37090ba7ca3ff32a12c9d809dc5867f0 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 19 Nov 2009 11:55:19 +0100 Subject: cfg80211: introduce capability for 4addr mode It's very likely that not many devices will support four-address mode in station or AP mode so introduce capability bits for both modes, set them in mac80211 and check them when userspace tries to use the mode. Also, keep track of 4addr in cfg80211 (wireless_dev) and not in mac80211 any more. mac80211 can also be improved for the VLAN case by not looking at the 4addr flag but maintaining the station pointer for it correctly. However, keep track of use_4addr for station mode in mac80211 to avoid all the derefs. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/wireless/util.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/wireless/util.c') diff --git a/net/wireless/util.c b/net/wireless/util.c index 5aa39f7cf9b9..17a7a4cfc617 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -659,6 +659,8 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev, return -EOPNOTSUPP; if (ntype != otype) { + dev->ieee80211_ptr->use_4addr = false; + switch (otype) { case NL80211_IFTYPE_ADHOC: cfg80211_leave_ibss(rdev, dev, false); @@ -682,5 +684,8 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev, WARN_ON(!err && dev->ieee80211_ptr->iftype != ntype); + if (!err && params && params->use_4addr != -1) + dev->ieee80211_ptr->use_4addr = params->use_4addr; + return err; } -- cgit v1.2.3 From ad4bb6f8883a13bb0f65b194dae36c62a02ac779 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 19 Nov 2009 00:56:30 +0100 Subject: cfg80211: disallow bridging managed/adhoc interfaces A number of people have tried to add a wireless interface (in managed mode) to a bridge and then complained that it doesn't work. It cannot work, however, because in 802.11 networks all packets need to be acknowledged and as such need to be sent to the right address. Promiscuous doesn't help here. The wireless address format used for these links has only space for three addresses, the * transmitter, which must be equal to the sender (origin) * receiver (on the wireless medium), which is the AP in the case of managed mode * the recipient (destination), which is on the APs local network segment In an IBSS, it is similar, but the receiver and recipient must match and the third address is used as the BSSID. To avoid such mistakes in the future, disallow adding a wireless interface to a bridge. Felix has recently added a four-address mode to the AP and client side that can be used (after negotiating that it is possible, which must happen out-of-band by setting up both sides) for bridging, so allow that case. Signed-off-by: Johannes Berg Acked-by: Stephen Hemminger Signed-off-by: John W. Linville --- net/wireless/util.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'net/wireless/util.c') diff --git a/net/wireless/util.c b/net/wireless/util.c index 17a7a4cfc617..59361fdcb5d0 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -658,6 +658,11 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev, !(rdev->wiphy.interface_modes & (1 << ntype))) return -EOPNOTSUPP; + /* if it's part of a bridge, reject changing type to station/ibss */ + if (dev->br_port && (ntype == NL80211_IFTYPE_ADHOC || + ntype == NL80211_IFTYPE_STATION)) + return -EBUSY; + if (ntype != otype) { dev->ieee80211_ptr->use_4addr = false; @@ -687,5 +692,31 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev, if (!err && params && params->use_4addr != -1) dev->ieee80211_ptr->use_4addr = params->use_4addr; + if (!err) { + dev->priv_flags &= ~IFF_DONT_BRIDGE; + switch (ntype) { + case NL80211_IFTYPE_STATION: + if (dev->ieee80211_ptr->use_4addr) + break; + /* fall through */ + case NL80211_IFTYPE_ADHOC: + dev->priv_flags |= IFF_DONT_BRIDGE; + break; + case NL80211_IFTYPE_AP: + case NL80211_IFTYPE_AP_VLAN: + case NL80211_IFTYPE_WDS: + case NL80211_IFTYPE_MESH_POINT: + /* bridging OK */ + break; + case NL80211_IFTYPE_MONITOR: + /* monitor can't bridge anyway */ + break; + case NL80211_IFTYPE_UNSPECIFIED: + case __NL80211_IFTYPE_AFTER_LAST: + /* not happening */ + break; + } + } + return err; } -- cgit v1.2.3