text: #include <errno.h>
  
  #include "nl80211.h"
  #include "iw.h"
  
  
  static int parse_vht_chunk(const char *arg, __u8 *nss, __u16 *mcs)
  {
  	unsigned int count, i;
  	unsigned int inss, mcs_start, mcs_end, tab[10];
  
  	*nss = 0; *mcs = 0;
  
  	if (strchr(arg, '-')) {
  		/* Format: NSS:MCS_START-MCS_END */
  		count = sscanf(arg, "%u:%u-%u", &inss, &mcs_start, &mcs_end);
  
  		if (count != 3)
  			return 0;
  
  		if (inss < 1 || inss > NL80211_VHT_NSS_MAX)
  			return 0;
  
  		if (mcs_start > mcs_end)
  			return 0;
  
  		if (mcs_start > 9 || mcs_end > 9)
  			return 0;
  
  		*nss = inss;
  		for (i = mcs_start; i <= mcs_end; i++)
  			*mcs |= 1 << i;
  
  	} else {
  		/* Format: NSS:MCSx,MCSy,... */
  		count = sscanf(arg, "%u:%u,%u,%u,%u,%u,%u,%u,%u,%u,%u", &inss,
  			   &tab[0], &tab[1], &tab[2], &tab[3], &tab[4], &tab[5],
  			   &tab[6], &tab[7], &tab[8], &tab[9]);
  
  		if (count < 2)
  			return 0;
  
  		if (inss < 1 || inss > NL80211_VHT_NSS_MAX)
  			return 0;
  
  		*nss = inss;
  		for (i = 0; i < count - 1; i++) {
  			if (tab[i] > 9)
  				return 0;
  			*mcs |= 1 << tab[i];
  		}
  	}
  
  	return 1;
  }
  
  static int setup_vht(struct nl80211_txrate_vht *txrate_vht,
  		     int argc, char **argv)
  {
  	__u8 nss;
  	__u16 mcs;
  	int i;
  
  	memset(txrate_vht, 0, sizeof(*txrate_vht));
  
  	for (i = 0; i < argc; i++) {
  		if (!parse_vht_chunk(argv[i], &nss, &mcs))
  			return 0;
  
  		nss--;
  		txrate_vht->mcs[nss] |= mcs;
  	}
  
  	return 1;
  }
  
  #define VHT_ARGC_MAX	100
  
  static int handle_bitrates(struct nl80211_state *state,
  			   struct nl_msg *msg,
  			   int argc, char **argv,
  			   enum id_input id)
  {
  	struct nlattr *nl_rates, *nl_band;
  	int i;
  	bool have_legacy_24 = false, have_legacy_5 = false;
  	uint8_t legacy_24[32], legacy_5[32];
  	int n_legacy_24 = 0, n_legacy_5 = 0;
  	uint8_t *legacy = NULL;
  	int *n_legacy = NULL;
  	bool have_ht_mcs_24 = false, have_ht_mcs_5 = false;
  	bool have_vht_mcs_24 = false, have_vht_mcs_5 = false;
  	uint8_t ht_mcs_24[77], ht_mcs_5[77];
  	int n_ht_mcs_24 = 0, n_ht_mcs_5 = 0;
  	struct nl80211_txrate_vht txrate_vht_24 = {};
  	struct nl80211_txrate_vht txrate_vht_5 = {};
  	uint8_t *mcs = NULL;
  	int *n_mcs = NULL;
  	char *vht_argv_5[VHT_ARGC_MAX] = {}; char *vht_argv_24[VHT_ARGC_MAX] = {};
  	char **vht_argv = NULL;
  	int vht_argc_5 = 0; int vht_argc_24 = 0;
  	int *vht_argc = NULL;
  	int sgi_24 = 0, sgi_5 = 0, lgi_24 = 0, lgi_5 = 0;
  
  	enum {
  		S_NONE,
  		S_LEGACY,
  		S_HT,
  		S_VHT,
  		S_GI,
  	} parser_state = S_NONE;
  
  	for (i = 0; i < argc; i++) {
  		char *end;
  		double tmpd;
  		long tmpl;
  
  		if (strcmp(argv[i], "legacy-2.4") == 0) {
  			if (have_legacy_24)
  				return 1;
  			parser_state = S_LEGACY;
  			legacy = legacy_24;
  			n_legacy = &n_legacy_24;
  			have_legacy_24 = true;
  		} else if (strcmp(argv[i], "legacy-5") == 0) {
  			if (have_legacy_5)
  				return 1;
  			parser_state = S_LEGACY;
  			legacy = legacy_5;
  			n_legacy = &n_legacy_5;
  			have_legacy_5 = true;
  		}
  		else if (strcmp(argv[i], "ht-mcs-2.4") == 0) {
  			if (have_ht_mcs_24)
  				return 1;
  			parser_state = S_HT;
  			mcs = ht_mcs_24;
  			n_mcs = &n_ht_mcs_24;
  			have_ht_mcs_24 = true;
  		} else if (strcmp(argv[i], "ht-mcs-5") == 0) {
  			if (have_ht_mcs_5)
  				return 1;
  			parser_state = S_HT;
  			mcs = ht_mcs_5;
  			n_mcs = &n_ht_mcs_5;
  			have_ht_mcs_5 = true;
  		} else if (strcmp(argv[i], "vht-mcs-2.4") == 0) {
  			if (have_vht_mcs_24)
  				return 1;
  			parser_state = S_VHT;
  			vht_argv = vht_argv_24;
  			vht_argc = &vht_argc_24;
  			have_vht_mcs_24 = true;
  		} else if (strcmp(argv[i], "vht-mcs-5") == 0) {
  			if (have_vht_mcs_5)
  				return 1;
  			parser_state = S_VHT;
  			vht_argv = vht_argv_5;
  			vht_argc = &vht_argc_5;
  			have_vht_mcs_5 = true;
  		} else if (strcmp(argv[i], "sgi-2.4") == 0) {
  			sgi_24 = 1;
  			parser_state = S_GI;
  		} else if (strcmp(argv[i], "sgi-5") == 0) {
  			sgi_5 = 1;
  			parser_state = S_GI;
  		} else if (strcmp(argv[i], "lgi-2.4") == 0) {
  			lgi_24 = 1;
  			parser_state = S_GI;
  		} else if (strcmp(argv[i], "lgi-5") == 0) {
  			lgi_5 = 1;
  			parser_state = S_GI;
  		} else switch (parser_state) {
  		case S_LEGACY:
  			tmpd = strtod(argv[i], &end);
  			if (*end != '\0')
  				return 1;
  			if (tmpd < 1 || tmpd > 255 * 2)
  				return 1;
  			legacy[(*n_legacy)++] = tmpd * 2;
  			break;
  		case S_HT:
  			tmpl = strtol(argv[i], &end, 0);
  			if (*end != '\0')
  				return 1;
  			if (tmpl < 0 || tmpl > 255)
  				return 1;
  			mcs[(*n_mcs)++] = tmpl;
  			break;
  		case S_VHT:
  			if (*vht_argc >= VHT_ARGC_MAX)
  				return 1;
  			vht_argv[(*vht_argc)++] = argv[i];
  			break;
  		case S_GI:
  			break;
  		default:
  			return 1;
  		}
  	}
  
  	if (have_vht_mcs_24)
  		if (!setup_vht(&txrate_vht_24, vht_argc_24, vht_argv_24))
  			return -EINVAL;
  
  	if (have_vht_mcs_5)
  		if (!setup_vht(&txrate_vht_5, vht_argc_5, vht_argv_5))
  			return -EINVAL;
  
  	if (sgi_5 && lgi_5)
  		return 1;
  
  	if (sgi_24 && lgi_24)
  		return 1;
  
  	nl_rates = nla_nest_start(msg, NL80211_ATTR_TX_RATES);
  	if (!nl_rates)
  		goto nla_put_failure;
  
  	if (have_legacy_24 || have_ht_mcs_24 || have_vht_mcs_24 || sgi_24 || lgi_24) {
  		nl_band = nla_nest_start(msg, NL80211_BAND_2GHZ);
  		if (!nl_band)
  			goto nla_put_failure;
  		if (have_legacy_24)
  			nla_put(msg, NL80211_TXRATE_LEGACY, n_legacy_24, legacy_24);
  		if (have_ht_mcs_24)
  			nla_put(msg, NL80211_TXRATE_HT, n_ht_mcs_24, ht_mcs_24);
  		if (have_vht_mcs_24)
  			nla_put(msg, NL80211_TXRATE_VHT, sizeof(txrate_vht_24), &txrate_vht_24);
  		if (sgi_24)
  			nla_put_u8(msg, NL80211_TXRATE_GI, NL80211_TXRATE_FORCE_SGI);
  		if (lgi_24)
  			nla_put_u8(msg, NL80211_TXRATE_GI, NL80211_TXRATE_FORCE_LGI);
  		nla_nest_end(msg, nl_band);
  	}
  
  	if (have_legacy_5 || have_ht_mcs_5 || have_vht_mcs_5 || sgi_5 || lgi_5) {
  		nl_band = nla_nest_start(msg, NL80211_BAND_5GHZ);
  		if (!nl_band)
  			goto nla_put_failure;
  		if (have_legacy_5)
  			nla_put(msg, NL80211_TXRATE_LEGACY, n_legacy_5, legacy_5);
  		if (have_ht_mcs_5)
  			nla_put(msg, NL80211_TXRATE_HT, n_ht_mcs_5, ht_mcs_5);
  		if (have_vht_mcs_5)
  			nla_put(msg, NL80211_TXRATE_VHT, sizeof(txrate_vht_5), &txrate_vht_5);
  		if (sgi_5)
  			nla_put_u8(msg, NL80211_TXRATE_GI, NL80211_TXRATE_FORCE_SGI);
  		if (lgi_5)
  			nla_put_u8(msg, NL80211_TXRATE_GI, NL80211_TXRATE_FORCE_LGI);
  		nla_nest_end(msg, nl_band);
  	}
  
  	nla_nest_end(msg, nl_rates);
  
  	return 0;
   nla_put_failure:
  	return -ENOBUFS;
  }
  
  #define DESCR_LEGACY "[legacy-<2.4|5> <legacy rate in Mbps>*]"
  #define DESCR DESCR_LEGACY " [ht-mcs-<2.4|5> <MCS index>*] [vht-mcs-<2.4|5> <NSS:MCSx,MCSy... | NSS:MCSx-MCSy>*] [sgi-2.4|lgi-2.4] [sgi-5|lgi-5]"
  
  COMMAND(set, bitrates, "[legacy-<2.4|5> <legacy rate in Mbps>*] [ht-mcs-<2.4|5> <MCS index>*] [vht-mcs-<2.4|5> <NSS:MCSx,MCSy... | NSS:MCSx-MCSy>*] [sgi-2.4|lgi-2.4] [sgi-5|lgi-5]",
  	NL80211_CMD_SET_TX_BITRATE_MASK, 0, CIB_NETDEV, handle_bitrates,
  	"Sets up the specified rate masks.\n"
  	"Not passing any arguments would clear the existing mask (if any).");
  