info.c

#include <errno.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
#include <netlink/genl/ctrl.h>
#include <netlink/msg.h>
#include <netlink/attr.h>
#include <linux/nl80211.h>

#include <net/if.h>

#include "iw.h"

static void print_flag(const char *name, int *open)
{
	if (!*open)
		printf(" (");
	else
		printf(", ");
	printf(name);
	*open = 1;
}

static int print_phy_handler(struct nl_msg *msg, void *arg)
{
	struct nlattr *tb_msg[NL80211_ATTR_MAX + 1];
	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));

	struct nlattr *tb_band[NL80211_BAND_ATTR_MAX + 1];

	struct nlattr *tb_freq[NL80211_FREQUENCY_ATTR_MAX + 1];
	static struct nla_policy freq_policy[NL80211_FREQUENCY_ATTR_MAX + 1] = {
		[NL80211_FREQUENCY_ATTR_FREQ] = { .type = NLA_U32 },
		[NL80211_FREQUENCY_ATTR_DISABLED] = { .type = NLA_FLAG },
		[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN] = { .type = NLA_FLAG },
		[NL80211_FREQUENCY_ATTR_NO_IBSS] = { .type = NLA_FLAG },
		[NL80211_FREQUENCY_ATTR_RADAR] = { .type = NLA_FLAG },
	};

	struct nlattr *tb_rate[NL80211_BITRATE_ATTR_MAX + 1];
	static struct nla_policy rate_policy[NL80211_BITRATE_ATTR_MAX + 1] = {
		[NL80211_BITRATE_ATTR_RATE] = { .type = NLA_U32 },
		[NL80211_BITRATE_ATTR_2GHZ_SHORTPREAMBLE] = { .type = NLA_FLAG },
	};

	struct nlattr *nl_band;
	struct nlattr *nl_freq;
	struct nlattr *nl_rate;
	int bandidx = 1;
	int rem_band, rem_freq, rem_rate;
	int open;

	nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
		  genlmsg_attrlen(gnlh, 0), NULL);

	if (!tb_msg[NL80211_ATTR_WIPHY_BANDS])
		return NL_SKIP;

	nla_for_each_nested(nl_band, tb_msg[NL80211_ATTR_WIPHY_BANDS], rem_band) {
		printf("Band %d:\n", bandidx);
		bandidx++;

		nla_parse(tb_band, NL80211_BAND_ATTR_MAX, nla_data(nl_band),
			  nla_len(nl_band), NULL);

		printf("\tFrequencies:\n");

		nla_for_each_nested(nl_freq, tb_band[NL80211_BAND_ATTR_FREQS], rem_freq) {
			nla_parse(tb_freq, NL80211_FREQUENCY_ATTR_MAX, nla_data(nl_freq),
				  nla_len(nl_freq), freq_policy);
			if (!tb_freq[NL80211_FREQUENCY_ATTR_FREQ])
				continue;
			printf("\t\t* %d MHz", nla_get_u32(tb_freq[NL80211_FREQUENCY_ATTR_FREQ]));
			open = 0;
			if (tb_freq[NL80211_FREQUENCY_ATTR_DISABLED])
				print_flag("disabled", &open);
			if (tb_freq[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN])
				print_flag("passive scanning", &open);
			if (tb_freq[NL80211_FREQUENCY_ATTR_NO_IBSS])
				print_flag("no IBSS", &open);
			if (tb_freq[NL80211_FREQUENCY_ATTR_RADAR])
				print_flag("radar detection", &open);
			if (open)
				printf(")");
			printf("\n");
		}

		printf("\tBitrates:\n");

		nla_for_each_nested(nl_rate, tb_band[NL80211_BAND_ATTR_RATES], rem_rate) {
			nla_parse(tb_rate, NL80211_BITRATE_ATTR_MAX, nla_data(nl_rate),
				  nla_len(nl_rate), rate_policy);
			if (!tb_rate[NL80211_BITRATE_ATTR_RATE])
				continue;
			printf("\t\t* %2.1f Mbps", 0.1 * nla_get_u32(tb_rate[NL80211_BITRATE_ATTR_RATE]));
			open = 0;
			if (tb_rate[NL80211_BITRATE_ATTR_2GHZ_SHORTPREAMBLE])
				print_flag("short preamble supported", &open);
			if (open)
				printf(")");
			printf("\n");
		}
	}

	return NL_SKIP;
}



static int ack_wait_handler(struct nl_msg *msg, void *arg)
{
	int *finished = arg;

	*finished = 1;
	return NL_STOP;
}

int handle_info(struct nl80211_state *state, char *phy, char *dev)
{
	struct nl_msg *msg;
	int err = -1;
	struct nl_cb *cb = NULL;
	int finished;

	msg = nlmsg_alloc();
	if (!msg) {
		fprintf(stderr, "failed to allocate netlink msg\n");
		return -1;
	}

	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
		    0, NL80211_CMD_GET_WIPHY, 0);
	if (dev)
		NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, if_nametoindex(dev));
	if (phy)
		return -1;	/* XXX TODO */

	cb = nl_cb_alloc(NL_CB_CUSTOM);
	if (!cb)
		goto out;

	if (nl_send_auto_complete(state->nl_handle, msg) < 0)
		goto out;

	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_phy_handler, NULL);
	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_wait_handler, &finished);

	err = nl_recvmsgs(state->nl_handle, cb);

	if (!finished)
		err = nl_wait_for_ack(state->nl_handle);

	if (err < 0)
		goto out;
	err = 0;

 out:
	nl_cb_put(cb);
 nla_put_failure:
	if (err)
		fprintf(stderr, "failed to get information: %d\n", err);
	nlmsg_free(msg);
	return err;
}