2017-02-08 12:10:13

by Ashok Raj Nagarajan

Subject: [PATCH v3] iw: Add support for controlling tx power for per station

This patch allows userspace to set transmit power, in mBm units, to a
station associated to the AP.

To set a limit tx power of 2000 mBm:
iw wlan0 station set <mac-addr> txpwr limit 2000

To revert the user defined tx power for a station:
iw wlan0 station set <mac-addr> txpwr auto

Signed-off-by: Ashok Raj Nagarajan <[email protected]>
---
v3:
- rebased

station.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)

diff --git a/station.c b/station.c
index f3e3da8..8364593 100644
--- a/station.c
+++ b/station.c
@@ -569,6 +569,7 @@ COMMAND(station, del, "<MAC address> [subtype <subtype>] [reason-code <code>]",
static const struct cmd *station_set_plink;
static const struct cmd *station_set_vlan;
static const struct cmd *station_set_mesh_power_mode;
+static const struct cmd *station_set_txpwr;

static const struct cmd *select_station_cmd(int argc, char **argv)
{
@@ -580,6 +581,8 @@ static const struct cmd *select_station_cmd(int argc, char **argv)
return station_set_vlan;
if (strcmp(argv[1], "mesh_power_mode") == 0)
return station_set_mesh_power_mode;
+ if (strcmp(argv[1], "txpwr") == 0)
+ return station_set_txpwr;
return NULL;
}

@@ -731,6 +734,72 @@ COMMAND_ALIAS(station, set, "<MAC address> mesh_power_mode "
"Set link-specific mesh power mode for this station",
select_station_cmd, station_set_mesh_power_mode);

+static int handle_station_set_txpwr(struct nl80211_state *state,
+ struct nl_msg *msg,
+ int argc, char **argv,
+ enum id_input id)
+{
+ enum nl80211_tx_power_setting type;
+ unsigned char mac_addr[ETH_ALEN];
+ unsigned int sta_txpwr = 0;
+ char *err = NULL;
+
+ if (argc != 3 && argc != 4)
+ return 1;
+
+ if (mac_addr_a2n(mac_addr, argv[0])) {
+ fprintf(stderr, "invalid mac address\n");
+ return 2;
+ }
+
+ NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr);
+ argc--;
+ argv++;
+
+ if (strcmp("txpwr", argv[0]) != 0)
+ return 1;
+ argc--;
+ argv++;
+
+ if (!strcmp(argv[0], "auto"))
+ type = NL80211_TX_POWER_AUTOMATIC;
+ else if (!strcmp(argv[0], "limit"))
+ type = NL80211_TX_POWER_LIMITED;
+ else {
+ printf("Invalid parameter: %s\n", argv[0]);
+ return 2;
+ }
+
+ NLA_PUT_U32(msg, NL80211_ATTR_STA_TX_POWER_SETTING, type);
+
+ if (type != NL80211_TX_POWER_AUTOMATIC) {
+ if (argc != 2) {
+ printf("Missing TX power level argument.\n");
+ return 2;
+ }
+
+ argc--;
+ argv++;
+
+ sta_txpwr = strtoul(argv[0], &err, 0);
+ NLA_PUT_U32(msg, NL80211_ATTR_STA_TX_POWER, sta_txpwr);
+ }
+
+ argc--;
+ argv++;
+
+ if (argc)
+ return 1;
+
+ return 0;
+ nla_put_failure:
+ return -ENOBUFS;
+}
+COMMAND_ALIAS(station, set, "<MAC address> txpwr <auto|limit> [<tx power mBm>]",
+ NL80211_CMD_SET_STATION, 0, CIB_NETDEV, handle_station_set_txpwr,
+ "Set Tx power for this station.",
+ select_station_cmd, station_set_txpwr);
+
static int handle_station_dump(struct nl80211_state *state,
struct nl_msg *msg,
int argc, char **argv,
--
1.9.1

2017-02-15 08:03:17

by Johannes Berg

Subject: Re: [PATCH v3] iw: Add support for controlling tx power for per station

> + sta_txpwr = strtoul(argv[0], &err, 0);

you should error-check this.

> + NLA_PUT_U32(msg, NL80211_ATTR_STA_TX_POWER,
> sta_txpwr);
> + }

> +}
> +COMMAND_ALIAS(station, set, "<MAC address> txpwr <auto|limit> [<tx
> power mBm>]",
>

Seems like that should be

<MAC address> txpwr <auto|limit <tx power dBm>>

or so?

I made that dBm there, doing that and parsing floating point numbers
would be nice I think.

johannes