cfg80211: advertise possible interface combinations

Add the ability to advertise interface combinations in nl80211.
This allows the driver to indicate what the combinations are
that it supports. "Combinations" of just a single interface are
implicit, as previously. Note that cfg80211 will enforce that
the restrictions are met, but not for all drivers yet (once all
drivers are updated, we can remove the flag and enforce for all).

When no combinations are actually supported, an empty list will
be exported so that userspace can know if the kernel exported
this info or not (although it isn't clear to me what tools using
the info should do if the kernel didn't export it).

Since some interface types are purely virtual/software and don't
fit the restrictions, those are exposed in a new list of pure SW
types, not subject to restrictions. This mainly exists to handle
AP-VLAN and monitor interfaces in mac80211.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 91 insertions, 14 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9ef8e287d61b..beac296b1fde 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -564,6 +564,88 @@ static int nl80211_key_allowed(struct wireless_dev *wdev)
         return 0;
 }
 
+static int nl80211_put_iftypes(struct sk_buff *msg, u32 attr, u16 ifmodes)
+{
+        struct nlattr *nl_modes = nla_nest_start(msg, attr);
+        int i;
+
+        if (!nl_modes)
+                goto nla_put_failure;
+
+        i = 0;
+        while (ifmodes) {
+                if (ifmodes & 1)
+                        NLA_PUT_FLAG(msg, i);
+                ifmodes >>= 1;
+                i++;
+        }
+
+        nla_nest_end(msg, nl_modes);
+        return 0;
+
+nla_put_failure:
+        return -ENOBUFS;
+}
+
+static int nl80211_put_iface_combinations(struct wiphy *wiphy,
+                                          struct sk_buff *msg)
+{
+        struct nlattr *nl_combis;
+        int i, j;
+
+        nl_combis = nla_nest_start(msg,
+                                NL80211_ATTR_INTERFACE_COMBINATIONS);
+        if (!nl_combis)
+                goto nla_put_failure;
+
+        for (i = 0; i < wiphy->n_iface_combinations; i++) {
+                const struct ieee80211_iface_combination *c;
+                struct nlattr *nl_combi, *nl_limits;
+
+                c = &wiphy->iface_combinations[i];
+
+                nl_combi = nla_nest_start(msg, i + 1);
+                if (!nl_combi)
+                        goto nla_put_failure;
+
+                nl_limits = nla_nest_start(msg, NL80211_IFACE_COMB_LIMITS);
+                if (!nl_limits)
+                        goto nla_put_failure;
+
+                for (j = 0; j < c->n_limits; j++) {
+                        struct nlattr *nl_limit;
+
+                        nl_limit = nla_nest_start(msg, j + 1);
+                        if (!nl_limit)
+                                goto nla_put_failure;
+                        NLA_PUT_U32(msg, NL80211_IFACE_LIMIT_MAX,
+                                    c->limits[j].max);
+                        if (nl80211_put_iftypes(msg, NL80211_IFACE_LIMIT_TYPES,
+                                                c->limits[j].types))
+                                goto nla_put_failure;
+                        nla_nest_end(msg, nl_limit);
+                }
+
+                nla_nest_end(msg, nl_limits);
+
+                if (c->beacon_int_infra_match)
+                        NLA_PUT_FLAG(msg,
+                                NL80211_IFACE_COMB_STA_AP_BI_MATCH);
+                NLA_PUT_U32(msg, NL80211_IFACE_COMB_NUM_CHANNELS,
+                            c->num_different_channels);
+                NLA_PUT_U32(msg, NL80211_IFACE_COMB_MAXNUM,
+                            c->max_interfaces);
+
+                nla_nest_end(msg, nl_combi);
+        }
+
+        nla_nest_end(msg, nl_combis);
+
+        return 0;
+nla_put_failure:
+        return -ENOBUFS;
+}
+
 static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                               struct cfg80211_registered_device *dev)
 {
@@ -571,13 +653,11 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
         struct nlattr *nl_bands, *nl_band;
         struct nlattr *nl_freqs, *nl_freq;
         struct nlattr *nl_rates, *nl_rate;
-        struct nlattr *nl_modes;
         struct nlattr *nl_cmds;
         enum ieee80211_band band;
         struct ieee80211_channel *chan;
         struct ieee80211_rate *rate;
         int i;
-        u16 ifmodes = dev->wiphy.interface_modes;
         const struct ieee80211_txrx_stypes *mgmt_stypes =
                                 dev->wiphy.mgmt_stypes;
 
@@ -637,20 +717,10 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                 }
         }
 
-        nl_modes = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_IFTYPES);
-        if (!nl_modes)
+        if (nl80211_put_iftypes(msg, NL80211_ATTR_SUPPORTED_IFTYPES,
+                                dev->wiphy.interface_modes))
                 goto nla_put_failure;
 
-        i = 0;
-        while (ifmodes) {
-                if (ifmodes & 1)
-                        NLA_PUT_FLAG(msg, i);
-                ifmodes >>= 1;
-                i++;
-        }
-
-        nla_nest_end(msg, nl_modes);
-
         nl_bands = nla_nest_start(msg, NL80211_ATTR_WIPHY_BANDS);
         if (!nl_bands)
                 goto nla_put_failure;
@@ -865,6 +935,13 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
                 nla_nest_end(msg, nl_wowlan);
         }
 
+        if (nl80211_put_iftypes(msg, NL80211_ATTR_SOFTWARE_IFTYPES,
+                                dev->wiphy.software_iftypes))
+                goto nla_put_failure;
+
+        if (nl80211_put_iface_combinations(&dev->wiphy, msg))
+                goto nla_put_failure;
+
         return genlmsg_end(msg, hdr);
 
  nla_put_failure: