[PATCH v2] cfg80211: add get reg command

[PATCH v2] cfg80211: add get reg command

[Luis R. Rodriguez]

This lets userspace request to get the currently set
regulatory domain.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
---

This v2 moves the locking during the entire call. Reason for this
is if we try to copy it we still are locking it during an interation
over it but if anything it'll just delay the locking even more due
to an extra kmalloc() being present, not to mention a new allocation
is being done. We avoid this by simply locking over the access of
cfg80211_regdomain. Thanks to Johannes for his pointers.

This patch applies on top of the inject patch:
[PATCH v3] mac80211: do not TX injected frames when not allowed

 include/linux/nl80211.h |    4 ++
 net/wireless/nl80211.c  |   82 +++++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/reg.c      |    6 +++
 net/wireless/reg.h      |    2 +
 4 files changed, 94 insertions(+), 0 deletions(-)

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 3357907..ef5c1d3 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -113,6 +113,8 @@
  * @NL80211_CMD_SET_BSS: Set BSS attributes for BSS identified by
  *	%NL80211_ATTR_IFINDEX.
  *
+ * @NL80211_CMD_GET_REG: ask the wireless core to send us its currently set
+ * 	regulatory domain.
  * @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
@@ -188,6 +190,8 @@ enum nl80211_commands {
 
 	NL80211_CMD_SET_MGMT_EXTRA_IE,
 
+	NL80211_CMD_GET_REG,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 3c6327d..7916149 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2094,6 +2094,82 @@ static int nl80211_set_mesh_params(struct sk_buff *skb, struct genl_info *info)
 
 #undef FILL_IN_MESH_PARAM_IF_SET
 
+static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
+{
+	struct sk_buff *msg;
+	const struct ieee80211_regdomain *regd;
+	void *hdr = NULL;
+	struct nlattr *nl_reg_rules;
+	unsigned int i;
+	int err = -EINVAL;
+
+	mutex_lock(&cfg80211_drv_mutex);
+	regd = reg_get_current_rd();
+
+	if (!regd)
+		goto out;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg) {
+		err = -ENOBUFS;
+		goto out;
+	}
+
+	hdr = nl80211hdr_put(msg, info->snd_pid, info->snd_seq, 0,
+			     NL80211_CMD_GET_REG);
+	if (!hdr)
+		goto nla_put_failure;
+
+	NLA_PUT_STRING(msg, NL80211_ATTR_REG_ALPHA2, regd->alpha2);
+
+	nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
+	if (!nl_reg_rules)
+		goto nla_put_failure;
+
+	for (i = 0; i < regd->n_reg_rules; i++) {
+		struct nlattr *nl_reg_rule;
+		const struct ieee80211_reg_rule *reg_rule;
+		const struct ieee80211_freq_range *freq_range;
+		const struct ieee80211_power_rule *power_rule;
+
+		reg_rule = &regd->reg_rules[i];
+		freq_range = &reg_rule->freq_range;
+		power_rule = &reg_rule->power_rule;
+
+		nl_reg_rule = nla_nest_start(msg, i);
+		if (!nl_reg_rule)
+			goto nla_put_failure;
+
+		NLA_PUT_U32(msg, NL80211_ATTR_REG_RULE_FLAGS,
+			reg_rule->flags);
+		NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_START,
+			freq_range->start_freq_khz);
+		NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_END,
+			freq_range->end_freq_khz);
+		NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_MAX_BW,
+			freq_range->max_bandwidth_khz);
+		NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_ANT_GAIN,
+			power_rule->max_antenna_gain);
+		NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_EIRP,
+			power_rule->max_eirp);
+
+		nla_nest_end(msg, nl_reg_rule);
+	}
+
+	nla_nest_end(msg, nl_reg_rules);
+
+	genlmsg_end(msg, hdr);
+	err = genlmsg_unicast(msg, info->snd_pid);
+	goto out;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	err = -EMSGSIZE;
+out:
+	mutex_unlock(&cfg80211_drv_mutex);
+	return err;
+}
+
 static int nl80211_set_reg(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *tb[NL80211_REG_RULE_ATTR_MAX + 1];
@@ -2334,6 +2410,12 @@ static struct genl_ops nl80211_ops[] = {
 		.flags = GENL_ADMIN_PERM,
 	},
 	{
+		.cmd = NL80211_CMD_GET_REG,
+		.doit = nl80211_get_reg,
+		.policy = nl80211_policy,
+		/* can be retrieved by unprivileged users */
+	},
+	{
 		.cmd = NL80211_CMD_SET_REG,
 		.doit = nl80211_set_reg,
 		.policy = nl80211_policy,
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index f643d39..6e2cf8c 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1598,6 +1598,12 @@ void reg_device_remove(struct wiphy *wiphy)
 	last_request->country_ie_env = ENVIRON_ANY;
 }
 
+/* caller is reponsible for locking while accessing this */
+const struct ieee80211_regdomain *reg_get_current_rd(void)
+{
+	return cfg80211_regdomain;
+}
+
 int regulatory_init(void)
 {
 	int err;
diff --git a/net/wireless/reg.h b/net/wireless/reg.h
index eb1dd5b..1dcbdfe 100644
--- a/net/wireless/reg.h
+++ b/net/wireless/reg.h
@@ -34,4 +34,6 @@ extern int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
 			     const char *alpha2, u32 country_ie_checksum,
 			     enum environment_cap country_ie_env);
 
+const struct ieee80211_regdomain *reg_get_current_rd(void);
+
 #endif  /* __NET_WIRELESS_REG_H */
-- 
1.5.6.4

Re: [PATCH v2] cfg80211: add get reg command

[Johannes Berg]

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On Wed, 2009-01-28 at 08:44 -0800, Luis R. Rodriguez wrote:

> +/* caller is reponsible for locking while accessing this */
> +const struct ieee80211_regdomain *reg_get_current_rd(void)
> +{
> +	return cfg80211_regdomain;
> +}

why not make the symbol cfg80211_regdomain non-static and use it
directly?

johannes

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Re: [PATCH v2] cfg80211: add get reg command

[Luis R. Rodriguez]

On Wed, Jan 28, 2009 at 10:47:42AM -0800, Johannes Berg wrote:
> On Wed, 2009-01-28 at 08:44 -0800, Luis R. Rodriguez wrote:
> 
> > +/* caller is reponsible for locking while accessing this */
> > +const struct ieee80211_regdomain *reg_get_current_rd(void)
> > +{
> > +	return cfg80211_regdomain;
> > +}
> 
> why not make the symbol cfg80211_regdomain non-static and use it
> directly?

Its only accessed once, but sure, OK.

  Luis