nl80211: add common API to configure SAR power limitations

NL80211_CMD_SET_SAR_SPECS is added to configure SAR from
user space. NL80211_ATTR_SAR_SPEC is used to pass the SAR
power specification when used with NL80211_CMD_SET_SAR_SPECS.

Wireless driver needs to register SAR type, supported frequency
ranges to wiphy, so user space can query it. The index in
frequency range is used to specify which sub band the power
limitation applies to. The SAR type is for compatibility, so later
other SAR mechanism can be implemented without breaking the user
space SAR applications.

Normal process is user space queries the SAR capability, and
gets the index of supported frequency ranges and associates the
power limitation with this index and sends to kernel.

Here is an example of message send to kernel:
8c 00 00 00 08 00 01 00 00 00 00 00 38 00 2b 81
08 00 01 00 00 00 00 00 2c 00 02 80 14 00 00 80
08 00 02 00 00 00 00 00 08 00 01 00 38 00 00 00
14 00 01 80 08 00 02 00 01 00 00 00 08 00 01 00
48 00 00 00

NL80211_CMD_SET_SAR_SPECS:  0x8c
NL80211_ATTR_WIPHY:     0x01(phy idx is 0)
NL80211_ATTR_SAR_SPEC:  0x812b (NLA_NESTED)
NL80211_SAR_ATTR_TYPE:  0x00 (NL80211_SAR_TYPE_POWER)
NL80211_SAR_ATTR_SPECS: 0x8002 (NLA_NESTED)
freq range 0 power: 0x38 in 0.25dbm unit (14dbm)
freq range 1 power: 0x48 in 0.25dbm unit (18dbm)

Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Abhishek Kumar <kuabhs@chromium.org>
Link: https://lore.kernel.org/r/20201203103728.3034-2-cjhuang@codeaurora.org
[minor edits, NLA parse cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 390e6e0f23ac..7db6079fab04 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -399,6 +399,18 @@ nl80211_unsol_bcast_probe_resp_policy[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_MAX +
 						       .len = IEEE80211_MAX_DATA_LEN }
 };
 
+static const struct nla_policy
+sar_specs_policy[NL80211_SAR_ATTR_SPECS_MAX + 1] = {
+	[NL80211_SAR_ATTR_SPECS_POWER] = { .type = NLA_S32 },
+	[NL80211_SAR_ATTR_SPECS_RANGE_INDEX] = {.type = NLA_U32 },
+};
+
+static const struct nla_policy
+sar_policy[NL80211_SAR_ATTR_MAX + 1] = {
+	[NL80211_SAR_ATTR_TYPE] = NLA_POLICY_MAX(NLA_U32, NUM_NL80211_SAR_TYPE),
+	[NL80211_SAR_ATTR_SPECS] = NLA_POLICY_NESTED_ARRAY(sar_specs_policy),
+};
+
 static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[0] = { .strict_start_type = NL80211_ATTR_HE_OBSS_PD },
 	[NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
@@ -719,6 +731,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 		NLA_POLICY_RANGE(NLA_U8, NL80211_SAE_PWE_HUNT_AND_PECK,
 				 NL80211_SAE_PWE_BOTH),
 	[NL80211_ATTR_RECONNECT_REQUESTED] = { .type = NLA_REJECT },
+	[NL80211_ATTR_SAR_SPEC] = NLA_POLICY_NESTED(sar_policy),
 };
 
 /* policy for the key attributes */
@@ -2095,6 +2108,56 @@ fail:
 	return -ENOBUFS;
 }
 
+static int
+nl80211_put_sar_specs(struct cfg80211_registered_device *rdev,
+		      struct sk_buff *msg)
+{
+	struct nlattr *sar_capa, *specs, *sub_freq_range;
+	u8 num_freq_ranges;
+	int i;
+
+	if (!rdev->wiphy.sar_capa)
+		return 0;
+
+	num_freq_ranges = rdev->wiphy.sar_capa->num_freq_ranges;
+
+	sar_capa = nla_nest_start(msg, NL80211_ATTR_SAR_SPEC);
+	if (!sar_capa)
+		return -ENOSPC;
+
+	if (nla_put_u32(msg, NL80211_SAR_ATTR_TYPE, rdev->wiphy.sar_capa->type))
+		goto fail;
+
+	specs = nla_nest_start(msg, NL80211_SAR_ATTR_SPECS);
+	if (!specs)
+		goto fail;
+
+	/* report supported freq_ranges */
+	for (i = 0; i < num_freq_ranges; i++) {
+		sub_freq_range = nla_nest_start(msg, i + 1);
+		if (!sub_freq_range)
+			goto fail;
+
+		if (nla_put_u32(msg, NL80211_SAR_ATTR_SPECS_START_FREQ,
+				rdev->wiphy.sar_capa->freq_ranges[i].start_freq))
+			goto fail;
+
+		if (nla_put_u32(msg, NL80211_SAR_ATTR_SPECS_END_FREQ,
+				rdev->wiphy.sar_capa->freq_ranges[i].end_freq))
+			goto fail;
+
+		nla_nest_end(msg, sub_freq_range);
+	}
+
+	nla_nest_end(msg, specs);
+	nla_nest_end(msg, sar_capa);
+
+	return 0;
+fail:
+	nla_nest_cancel(msg, sar_capa);
+	return -ENOBUFS;
+}
+
 struct nl80211_dump_wiphy_state {
 	s64 filter_wiphy;
 	long start;
@@ -2344,6 +2407,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			CMD(set_multicast_to_unicast, SET_MULTICAST_TO_UNICAST);
 			CMD(update_connect_params, UPDATE_CONNECT_PARAMS);
 			CMD(update_ft_ies, UPDATE_FT_IES);
+			if (rdev->wiphy.sar_capa)
+				CMD(set_sar_specs, SET_SAR_SPECS);
 		}
 #undef CMD
 
@@ -2669,6 +2734,11 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 
 		if (nl80211_put_tid_config_support(rdev, msg))
 			goto nla_put_failure;
+		state->split_start++;
+		break;
+	case 16:
+		if (nl80211_put_sar_specs(rdev, msg))
+			goto nla_put_failure;
 
 		/* done */
 		state->split_start = 0;
@@ -14668,6 +14738,111 @@ static void nl80211_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
 	}
 }
 
+static int nl80211_set_sar_sub_specs(struct cfg80211_registered_device *rdev,
+				     struct cfg80211_sar_specs *sar_specs,
+				     struct nlattr *spec[], int index)
+{
+	u32 range_index, i;
+
+	if (!sar_specs || !spec)
+		return -EINVAL;
+
+	if (!spec[NL80211_SAR_ATTR_SPECS_POWER] ||
+	    !spec[NL80211_SAR_ATTR_SPECS_RANGE_INDEX])
+		return -EINVAL;
+
+	range_index = nla_get_u32(spec[NL80211_SAR_ATTR_SPECS_RANGE_INDEX]);
+
+	/* check if range_index exceeds num_freq_ranges */
+	if (range_index >= rdev->wiphy.sar_capa->num_freq_ranges)
+		return -EINVAL;
+
+	/* check if range_index duplicates */
+	for (i = 0; i < index; i++) {
+		if (sar_specs->sub_specs[i].freq_range_index == range_index)
+			return -EINVAL;
+	}
+
+	sar_specs->sub_specs[index].power =
+		nla_get_s32(spec[NL80211_SAR_ATTR_SPECS_POWER]);
+
+	sar_specs->sub_specs[index].freq_range_index = range_index;
+
+	return 0;
+}
+
+static int nl80211_set_sar_specs(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct nlattr *spec[NL80211_SAR_ATTR_SPECS_MAX + 1];
+	struct nlattr *tb[NL80211_SAR_ATTR_MAX + 1];
+	struct cfg80211_sar_specs *sar_spec;
+	enum nl80211_sar_type type;
+	struct nlattr *spec_list;
+	u32 specs;
+	int rem, err;
+
+	if (!rdev->wiphy.sar_capa || !rdev->ops->set_sar_specs)
+		return -EOPNOTSUPP;
+
+	if (!info->attrs[NL80211_ATTR_SAR_SPEC])
+		return -EINVAL;
+
+	nla_parse_nested(tb, NL80211_SAR_ATTR_MAX,
+			 info->attrs[NL80211_ATTR_SAR_SPEC],
+			 NULL, NULL);
+
+	if (!tb[NL80211_SAR_ATTR_TYPE] || !tb[NL80211_SAR_ATTR_SPECS])
+		return -EINVAL;
+
+	type = nla_get_u32(tb[NL80211_SAR_ATTR_TYPE]);
+	if (type != rdev->wiphy.sar_capa->type)
+		return -EINVAL;
+
+	specs = 0;
+	nla_for_each_nested(spec_list, tb[NL80211_SAR_ATTR_SPECS], rem)
+		specs++;
+
+	if (specs > rdev->wiphy.sar_capa->num_freq_ranges)
+		return -EINVAL;
+
+	sar_spec = kzalloc(sizeof(*sar_spec) +
+			   specs * sizeof(struct cfg80211_sar_sub_specs),
+			   GFP_KERNEL);
+	if (!sar_spec)
+		return -ENOMEM;
+
+	sar_spec->type = type;
+	specs = 0;
+	nla_for_each_nested(spec_list, tb[NL80211_SAR_ATTR_SPECS], rem) {
+		nla_parse_nested(spec, NL80211_SAR_ATTR_SPECS_MAX,
+				 spec_list, NULL, NULL);
+
+		switch (type) {
+		case NL80211_SAR_TYPE_POWER:
+			if (nl80211_set_sar_sub_specs(rdev, sar_spec,
+						      spec, specs)) {
+				err = -EINVAL;
+				goto error;
+			}
+			break;
+		default:
+			err = -EINVAL;
+			goto error;
+		}
+		specs++;
+	}
+
+	sar_spec->num_sub_specs = specs;
+
+	rdev->cur_cmd_info = info;
+	err = rdev_set_sar_specs(rdev, sar_spec);
+	rdev->cur_cmd_info = NULL;
+error:
+	kfree(sar_spec);
+	return err;
+}
+
 static const struct genl_ops nl80211_ops[] = {
 	{
 		.cmd = NL80211_CMD_GET_WIPHY,
@@ -15521,6 +15696,14 @@ static const struct genl_small_ops nl80211_small_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_SET_SAR_SPECS,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = nl80211_set_sar_specs,
+		.flags = GENL_UNS_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_WIPHY |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_family nl80211_fam __ro_after_init = {