[PATCH 1/8] util: Add generic frequency/channel command line handler

[Benjamin Berg <benjamin@sipsolutions.net>]

From: Benjamin Berg <benjamin.berg@open-mesh.com>

The ability to parse channel definitions is required in a lot of places
inside iw. However, right now each of these duplicates a lot of code to
handle it.

So add a new helper which can be used everywhere.

Signed-off-by: Benjamin Berg <benjamin.berg@open-mesh.com>
---
 iw.h   |  10 +++
 util.c | 239 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 249 insertions(+)

diff --git a/iw.h b/iw.h
index 2837bd3..7d56391 100644
--- a/iw.h
+++ b/iw.h
@@ -70,6 +70,14 @@ struct chanmode {
 	int chantype; /* for older kernel */
 };
 
+struct chandef {
+	enum nl80211_chan_width width;
+
+	unsigned int control_freq;
+	unsigned int center_freq1;
+	unsigned int center_freq2;
+};
+
 #define ARRAY_SIZE(ar) (sizeof(ar)/sizeof(ar[0]))
 #define DIV_ROUND_UP(x, y) (((x) + (y - 1)) / (y))
 
@@ -150,6 +158,8 @@ int parse_hex_mask(char *hexmask, unsigned char **result, size_t *result_len,
 unsigned char *parse_hex(char *hex, size_t *outlen);
 
 int parse_keys(struct nl_msg *msg, char **argv, int argc);
+int parse_freqchan(struct chandef *chandef, bool chan, int argc, char **argv, int *parsed);
+int put_chandef(struct nl_msg *msg, struct chandef *chandef);
 
 void print_ht_mcs(const __u8 *mcs);
 void print_ampdu_length(__u8 exponent);
diff --git a/util.c b/util.c
index a338464..833b1ce 100644
--- a/util.c
+++ b/util.c
@@ -469,6 +469,245 @@ int parse_keys(struct nl_msg *msg, char **argv, int argc)
 	return 2;
 }
 
+static int parse_freqs(struct chandef *chandef, int argc, char **argv,
+		       int *parsed)
+{
+	static const struct {
+		const char *name;
+		unsigned int val;
+	} bwmap[] = {
+		{ .name = "5", .val = NL80211_CHAN_WIDTH_5, },
+		{ .name = "10", .val = NL80211_CHAN_WIDTH_10, },
+		{ .name = "20", .val = NL80211_CHAN_WIDTH_20, },
+		{ .name = "40", .val = NL80211_CHAN_WIDTH_40, },
+		{ .name = "80", .val = NL80211_CHAN_WIDTH_80, },
+		{ .name = "80+80", .val = NL80211_CHAN_WIDTH_80P80, },
+		{ .name = "160", .val = NL80211_CHAN_WIDTH_160, },
+	};
+	uint32_t freq;
+	unsigned int i, bwval = NL80211_CHAN_WIDTH_20_NOHT;
+	char *end;
+
+	if (argc < 1)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(bwmap); i++) {
+		if (strcasecmp(bwmap[i].name, argv[0]) == 0) {
+			bwval = bwmap[i].val;
+			*parsed += 1;
+			break;
+		}
+	}
+	chandef->width = bwval;
+
+	/* First argument was not understood, give up gracefully. */
+	if (bwval == NL80211_CHAN_WIDTH_20_NOHT)
+		return 0;
+
+	if (argc < 2)
+		return 0;
+
+	/* center freq 1 */
+	if (!*argv[1])
+		return 0;
+	freq = strtoul(argv[1], &end, 10);
+	if (*end)
+		return 0;
+	*parsed += 1;
+
+	chandef->center_freq1 = freq;
+
+	if (argc < 3)
+		return 0;
+
+	/* center freq 2 */
+	if (!*argv[2])
+		return 0;
+	freq = strtoul(argv[2], &end, 10);
+	if (*end)
+		return 0;
+	chandef->center_freq2 = freq;
+
+	*parsed += 1;
+
+	return 0;
+}
+
+
+/**
+ * parse_freqchan - Parse frequency or channel definition
+ *
+ * @chandef: chandef structure to be filled in
+ * @chan: Boolean whether to parse a channel or frequency based specifier
+ * @argc: Number of arguments
+ * @argv: Array of string arguments
+ * @parsed: Pointer to return the number of used arguments, or NULL to error
+ *          out if any argument is left unused.
+ *
+ * The given chandef structure will be filled in from the command line
+ * arguments. argc/argv will be updated so that further arguments from the
+ * command line can be parsed.
+ *
+ * Note that no integer argument may follow a frequency definition to allow the
+ * user to skip the center frequency definition(s).
+ *
+ * The working specifier if chan is set are:
+ *   <channel> [NOHT|HT20|HT40+|HT40-|5MHz|10MHz|80MHz]
+ *
+ * And if frequency is set:
+ *   <freq> [NOHT|HT20|HT40+|HT40-|5MHz|10MHz|80MHz]
+ *   <control freq> [5|10|20|40|80|80+80|160] [<center1_freq> [<center2_freq>]]
+ *
+ * If the mode/channel width is not given the NOHT is assumed.
+ *
+ * Return: Number of used arguments, zero or negative error number otherwise
+ */
+int parse_freqchan(struct chandef *chandef, bool chan, int argc, char **argv,
+		   int *parsed)
+{
+	char *end;
+	static const struct chanmode chanmode[] = {
+		{ .name = "HT20",
+		  .width = NL80211_CHAN_WIDTH_20,
+		  .freq1_diff = 0,
+		  .chantype = NL80211_CHAN_HT20 },
+		{ .name = "HT40+",
+		  .width = NL80211_CHAN_WIDTH_40,
+		  .freq1_diff = 10,
+		  .chantype = NL80211_CHAN_HT40PLUS },
+		{ .name = "HT40-",
+		  .width = NL80211_CHAN_WIDTH_40,
+		  .freq1_diff = -10,
+		  .chantype = NL80211_CHAN_HT40MINUS },
+		{ .name = "NOHT",
+		  .width = NL80211_CHAN_WIDTH_20_NOHT,
+		  .freq1_diff = 0,
+		  .chantype = NL80211_CHAN_NO_HT },
+		{ .name = "5MHz",
+		  .width = NL80211_CHAN_WIDTH_5,
+		  .freq1_diff = 0,
+		  .chantype = -1 },
+		{ .name = "10MHz",
+		  .width = NL80211_CHAN_WIDTH_10,
+		  .freq1_diff = 0,
+		  .chantype = -1 },
+		{ .name = "80MHz",
+		  .width = NL80211_CHAN_WIDTH_80,
+		  .freq1_diff = 0,
+		  .chantype = -1 },
+	};
+	const struct chanmode *chanmode_selected = NULL;
+	unsigned int freq;
+	unsigned int i;
+	int _parsed = 0;
+	int res = 0;
+
+	if (argc < 1)
+		return 1;
+
+	if (!argv[0])
+		goto out;
+	freq = strtoul(argv[0], &end, 10);
+	if (*end) {
+		res = 1;
+		goto out;
+	}
+
+	_parsed += 1;
+
+	memset(chandef, 0, sizeof(struct chandef));
+
+	if (chan) {
+		enum nl80211_band band;
+
+		band = freq <= 14 ? NL80211_BAND_2GHZ : NL80211_BAND_5GHZ;
+		freq = ieee80211_channel_to_frequency(freq, band);
+	}
+	chandef->control_freq = freq;
+	/* Assume 20MHz NOHT channel for now. */
+	chandef->center_freq1 = freq;
+
+	/* Try to parse HT mode definitions */
+	if (argc > 1) {
+		for (i = 0; i < ARRAY_SIZE(chanmode); i++) {
+			if (strcasecmp(chanmode[i].name, argv[1]) == 0) {
+				chanmode_selected = &chanmode[i];
+				_parsed += 1;
+				break;
+			}
+		}
+	}
+
+	/* channel mode given, use it and return. */
+	if (chanmode_selected) {
+		chandef->center_freq1 = get_cf1(chanmode_selected, freq);
+		chandef->width = chanmode_selected->width;
+		goto out;
+	}
+
+	/* This was a only a channel definition, nothing further may follow. */
+	if (chan)
+		goto out;
+
+	res = parse_freqs(chandef, argc - 1, argv + 1, &_parsed);
+
+ out:
+	/* Error out if parsed is NULL. */
+	if (!parsed && _parsed != argc)
+		return 1;
+
+	if (parsed)
+		*parsed = _parsed;
+
+	return res;
+}
+
+int put_chandef(struct nl_msg *msg, struct chandef *chandef)
+{
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_FREQ, chandef->control_freq);
+	NLA_PUT_U32(msg, NL80211_ATTR_CHANNEL_WIDTH, chandef->width);
+
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		NLA_PUT_U32(msg,
+			    NL80211_ATTR_WIPHY_CHANNEL_TYPE,
+			    NL80211_CHAN_NO_HT);
+		break;
+	case NL80211_CHAN_WIDTH_20:
+		NLA_PUT_U32(msg,
+			    NL80211_ATTR_WIPHY_CHANNEL_TYPE,
+			    NL80211_CHAN_HT20);
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		if (chandef->control_freq > chandef->center_freq1)
+			NLA_PUT_U32(msg,
+				    NL80211_ATTR_WIPHY_CHANNEL_TYPE,
+				    NL80211_CHAN_HT40MINUS);
+		else
+			NLA_PUT_U32(msg,
+				    NL80211_ATTR_WIPHY_CHANNEL_TYPE,
+				    NL80211_CHAN_HT40PLUS);
+		break;
+	default:
+		break;
+	}
+
+	if (chandef->center_freq1)
+		NLA_PUT_U32(msg,
+			    NL80211_ATTR_CENTER_FREQ1,
+			    chandef->center_freq1);
+
+	if (chandef->center_freq2)
+		NLA_PUT_U32(msg,
+			    NL80211_ATTR_CENTER_FREQ2,
+			    chandef->center_freq2);
+
+	return 0;
+
+ nla_put_failure:
+	return -ENOBUFS;
+}
+
 static void print_mcs_index(const __u8 *mcs)
 {
 	int mcs_bit, prev_bit = -2, prev_cont = 0;
-- 
2.10.2