cfg80211: allow usermode to query wiphy specific regdom

If a wiphy-idx is specified, the kernel will return the wiphy specific
regdomain, if such exists. Otherwise return the global regdom.

When no wiphy-idx is specified, return the global regdomain as well as
all wiphy-specific regulatory domains in the system, via a new nested
list of attributes.

Add a new attribute for each wiphy-specific regdomain, for usermode to
identify it as such.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 151 insertions, 35 deletions

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index b37bd5a1cb82..2d384d041224 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -252,7 +252,15 @@
  *      %NL80211_ATTR_IFINDEX.
  *
  * @NL80211_CMD_GET_REG: ask the wireless core to send us its currently set
- *      regulatory domain.
+ *      regulatory domain. If %NL80211_ATTR_WIPHY is specified and the device
+ *      has a private regulatory domain, it will be returned. Otherwise, the
+ *      global regdomain will be returned.
+ *      A device will have a private regulatory domain if it uses the
+ *      regulatory_hint() API. Even when a private regdomain is used the channel
+ *      information will still be mended according to further hints from
+ *      the regulatory core to help with compliance. A dump version of this API
+ *      is now available which will returns the global regdomain as well as
+ *      all private regdomains of present wiphys (for those that have it).
  * @NL80211_CMD_SET_REG: Set current regulatory domain. CRDA sends this command
  *      after being queried by the kernel. CRDA replies by sending a regulatory
  *      domain structure which consists of %NL80211_ATTR_REG_ALPHA set to our
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index a17d6bc6b22c..2d5dc428c5ab 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5327,42 +5327,20 @@ static int nl80211_update_mesh_config(struct sk_buff *skb,
         return err;
 }
 
-static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
+static int nl80211_put_regdom(const struct ieee80211_regdomain *regdom,
+                              struct sk_buff *msg)
 {
-        const struct ieee80211_regdomain *regdom;
-        struct sk_buff *msg;
-        void *hdr = NULL;
         struct nlattr *nl_reg_rules;
         unsigned int i;
 
-        if (!cfg80211_regdomain)
-                return -EINVAL;
-
-        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
-        if (!msg)
-                return -ENOBUFS;
-
-        hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
-                             NL80211_CMD_GET_REG);
-        if (!hdr)
-                goto put_failure;
-
-        if (reg_last_request_cell_base() &&
-            nla_put_u32(msg, NL80211_ATTR_USER_REG_HINT_TYPE,
-                        NL80211_USER_REG_HINT_CELL_BASE))
-                goto nla_put_failure;
-
-        rcu_read_lock();
-        regdom = rcu_dereference(cfg80211_regdomain);
-
         if (nla_put_string(msg, NL80211_ATTR_REG_ALPHA2, regdom->alpha2) ||
             (regdom->dfs_region &&
              nla_put_u8(msg, NL80211_ATTR_DFS_REGION, regdom->dfs_region)))
-                goto nla_put_failure_rcu;
+                goto nla_put_failure;
 
         nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
         if (!nl_reg_rules)
-                goto nla_put_failure_rcu;
+                goto nla_put_failure;
 
         for (i = 0; i < regdom->n_reg_rules; i++) {
                 struct nlattr *nl_reg_rule;
@@ -5377,7 +5355,7 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
 
                 nl_reg_rule = nla_nest_start(msg, i);
                 if (!nl_reg_rule)
-                        goto nla_put_failure_rcu;
+                        goto nla_put_failure;
 
                 max_bandwidth_khz = freq_range->max_bandwidth_khz;
                 if (!max_bandwidth_khz)
@@ -5398,13 +5376,64 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
                                 power_rule->max_eirp) ||
                     nla_put_u32(msg, NL80211_ATTR_DFS_CAC_TIME,
                                 reg_rule->dfs_cac_ms))
-                        goto nla_put_failure_rcu;
+                        goto nla_put_failure;
 
                 nla_nest_end(msg, nl_reg_rule);
         }
-        rcu_read_unlock();
 
         nla_nest_end(msg, nl_reg_rules);
+        return 0;
+
+nla_put_failure:
+        return -EMSGSIZE;
+}
+
+static int nl80211_get_reg_do(struct sk_buff *skb, struct genl_info *info)
+{
+        const struct ieee80211_regdomain *regdom = NULL;
+        struct cfg80211_registered_device *rdev;
+        struct wiphy *wiphy = NULL;
+        struct sk_buff *msg;
+        void *hdr;
+
+        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+        if (!msg)
+                return -ENOBUFS;
+
+        hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
+                             NL80211_CMD_GET_REG);
+        if (!hdr)
+                goto put_failure;
+
+        if (info->attrs[NL80211_ATTR_WIPHY]) {
+                rdev = cfg80211_get_dev_from_info(genl_info_net(info), info);
+                if (IS_ERR(rdev)) {
+                        nlmsg_free(msg);
+                        return PTR_ERR(rdev);
+                }
+
+                wiphy = &rdev->wiphy;
+                regdom = get_wiphy_regdom(wiphy);
+
+                if (regdom &&
+                    nla_put_u32(msg, NL80211_ATTR_WIPHY, get_wiphy_idx(wiphy)))
+                        goto nla_put_failure;
+        }
+
+        if (!wiphy && reg_last_request_cell_base() &&
+            nla_put_u32(msg, NL80211_ATTR_USER_REG_HINT_TYPE,
+                        NL80211_USER_REG_HINT_CELL_BASE))
+                goto nla_put_failure;
+
+        rcu_read_lock();
+
+        if (!regdom)
+                regdom = rcu_dereference(cfg80211_regdomain);
+
+        if (nl80211_put_regdom(regdom, msg))
+                goto nla_put_failure_rcu;
+
+        rcu_read_unlock();
 
         genlmsg_end(msg, hdr);
         return genlmsg_reply(msg, info);
@@ -5418,6 +5447,79 @@ put_failure:
         return -EMSGSIZE;
 }
 
+static int nl80211_send_regdom(struct sk_buff *msg, struct netlink_callback *cb,
+                               u32 seq, int flags, struct wiphy *wiphy,
+                               const struct ieee80211_regdomain *regdom)
+{
+        void *hdr = nl80211hdr_put(msg, NETLINK_CB(cb->skb).portid, seq, flags,
+                                   NL80211_CMD_GET_REG);
+
+        if (!hdr)
+                return -1;
+
+        genl_dump_check_consistent(cb, hdr, &nl80211_fam);
+
+        if (nl80211_put_regdom(regdom, msg))
+                goto nla_put_failure;
+
+        if (!wiphy && reg_last_request_cell_base() &&
+            nla_put_u32(msg, NL80211_ATTR_USER_REG_HINT_TYPE,
+                        NL80211_USER_REG_HINT_CELL_BASE))
+                goto nla_put_failure;
+
+        if (wiphy &&
+            nla_put_u32(msg, NL80211_ATTR_WIPHY, get_wiphy_idx(wiphy)))
+                goto nla_put_failure;
+
+        return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        return -EMSGSIZE;
+}
+
+static int nl80211_get_reg_dump(struct sk_buff *skb,
+                                struct netlink_callback *cb)
+{
+        const struct ieee80211_regdomain *regdom = NULL;
+        struct cfg80211_registered_device *rdev;
+        int err, reg_idx, start = cb->args[2];
+
+        rtnl_lock();
+
+        if (cfg80211_regdomain && start == 0) {
+                err = nl80211_send_regdom(skb, cb, cb->nlh->nlmsg_seq,
+                                          NLM_F_MULTI, NULL,
+                                          rtnl_dereference(cfg80211_regdomain));
+                if (err < 0)
+                        goto out_err;
+        }
+
+        /* the global regdom is idx 0 */
+        reg_idx = 1;
+        list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+                regdom = get_wiphy_regdom(&rdev->wiphy);
+                if (!regdom)
+                        continue;
+
+                if (++reg_idx <= start)
+                        continue;
+
+                err = nl80211_send_regdom(skb, cb, cb->nlh->nlmsg_seq,
+                                          NLM_F_MULTI, &rdev->wiphy, regdom);
+                if (err < 0) {
+                        reg_idx--;
+                        break;
+                }
+        }
+
+        cb->args[2] = reg_idx;
+        err = skb->len;
+out_err:
+        rtnl_unlock();
+        return err;
+}
+
 static int nl80211_set_reg(struct sk_buff *skb, struct genl_info *info)
 {
         struct nlattr *tb[NL80211_REG_RULE_ATTR_MAX + 1];
@@ -10225,7 +10327,8 @@ static const struct genl_ops nl80211_ops[] = {
         },
         {
                 .cmd = NL80211_CMD_GET_REG,
-                .doit = nl80211_get_reg,
+                .doit = nl80211_get_reg_do,
+                .dumpit = nl80211_get_reg_dump,
                 .policy = nl80211_policy,
                 .internal_flags = NL80211_FLAG_NEED_RTNL,
                 /* can be retrieved by unprivileged users */
@@ -10983,9 +11086,13 @@ void nl80211_send_reg_change_event(struct regulatory_request *request)
                         goto nla_put_failure;
         }
 
-        if (request->wiphy_idx != WIPHY_IDX_INVALID &&
-            nla_put_u32(msg, NL80211_ATTR_WIPHY, request->wiphy_idx))
-                goto nla_put_failure;
+        if (request->wiphy_idx != WIPHY_IDX_INVALID) {
+                struct wiphy *wiphy = wiphy_idx_to_wiphy(request->wiphy_idx);
+
+                if (wiphy &&
+                    nla_put_u32(msg, NL80211_ATTR_WIPHY, request->wiphy_idx))
+                        goto nla_put_failure;
+        }
 
         genlmsg_end(msg, hdr);
 
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index d83480b6efde..2d9760084b74 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -142,7 +142,7 @@ static const struct ieee80211_regdomain *get_cfg80211_regdom(void)
         return rtnl_dereference(cfg80211_regdomain);
 }
 
-static const struct ieee80211_regdomain *get_wiphy_regdom(struct wiphy *wiphy)
+const struct ieee80211_regdomain *get_wiphy_regdom(struct wiphy *wiphy)
 {
         return rtnl_dereference(wiphy->regd);
 }
diff --git a/net/wireless/reg.h b/net/wireless/reg.h
index 5e48031ccb9a..4b45d6e61d24 100644
--- a/net/wireless/reg.h
+++ b/net/wireless/reg.h
@@ -38,6 +38,7 @@ unsigned int reg_get_max_bandwidth(const struct ieee80211_regdomain *rd,
                                    const struct ieee80211_reg_rule *rule);
 
 bool reg_last_request_cell_base(void);
+const struct ieee80211_regdomain *get_wiphy_regdom(struct wiphy *wiphy);
 
 /**
  * regulatory_hint_found_beacon - hints a beacon was found on a channel