text: #include <stdint.h>
  #include <stdbool.h>
  #include <net/if.h>
  #include <errno.h>
  #include "iw.h"
  
  static int no_seq_check(struct nl_msg *msg, void *arg)
  {
  	return NL_OK;
  }
  
  struct ieee80211_beacon_channel {
  	__u16 center_freq;
  	bool passive_scan;
  	bool no_ibss;
  };
  
  static int parse_beacon_hint_chan(struct nlattr *tb,
  				  struct ieee80211_beacon_channel *chan)
  {
  	struct nlattr *tb_freq[NL80211_FREQUENCY_ATTR_MAX + 1];
  	static struct nla_policy beacon_freq_policy[NL80211_FREQUENCY_ATTR_MAX + 1] = {
  		[NL80211_FREQUENCY_ATTR_FREQ] = { .type = NLA_U32 },
  		[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN] = { .type = NLA_FLAG },
  		[NL80211_FREQUENCY_ATTR_NO_IBSS] = { .type = NLA_FLAG },
  	};
  
  	if (nla_parse_nested(tb_freq,
  			     NL80211_FREQUENCY_ATTR_MAX,
  			     tb,
  			     beacon_freq_policy))
  		return -EINVAL;
  
  	chan->center_freq = nla_get_u32(tb_freq[NL80211_FREQUENCY_ATTR_FREQ]);
  
  	if (tb_freq[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN])
  		chan->passive_scan = true;
  	if (tb_freq[NL80211_FREQUENCY_ATTR_NO_IBSS])
  		chan->no_ibss = true;
  
  	return 0;
  }
  
  static void print_frame(struct print_event_args *args, struct nlattr *attr)
  {
  	uint8_t *frame;
  	size_t len;
  	int i;
  	char macbuf[6*3];
  	uint16_t tmp;
  
  	if (!attr)
  		printf(" [no frame]");
  
  	frame = nla_data(attr);
  	len = nla_len(attr);
  
  	if (len < 26) {
  		printf(" [invalid frame: ");
  		goto print_frame;
  	}
  
  	mac_addr_n2a(macbuf, frame + 10);
  	printf(" %s -> ", macbuf);
  	mac_addr_n2a(macbuf, frame + 4);
  	printf("%s", macbuf);
  
  	switch (frame[0] & 0xfc) {
  	case 0x10: /* assoc resp */
  	case 0x30: /* reassoc resp */
  		/* status */
  		tmp = (frame[27] << 8) + frame[26];
  		printf(" status: %d: %s", tmp, get_status_str(tmp));
  		break;
  	case 0x00: /* assoc req */
  	case 0x20: /* reassoc req */
  		break;
  	case 0xb0: /* auth */
  		/* status */
  		tmp = (frame[29] << 8) + frame[28];
  		printf(" status: %d: %s", tmp, get_status_str(tmp));
  		break;
  		break;
  	case 0xa0: /* disassoc */
  	case 0xc0: /* deauth */
  		/* reason */
  		tmp = (frame[25] << 8) + frame[24];
  		printf(" reason %d: %s", tmp, get_reason_str(tmp));
  		break;
  	}
  
  	if (!args->frame)
  		return;
  
  	printf(" [frame:");
  
   print_frame:
  	for (i = 0; i < len; i++)
  		printf(" %.02x", frame[i]);
  	printf("]");
  }
  
  static void parse_cqm_event(struct nlattr **attrs)
  {
  	static struct nla_policy cqm_policy[NL80211_ATTR_CQM_MAX + 1] = {
  		[NL80211_ATTR_CQM_RSSI_THOLD] = { .type = NLA_U32 },
  		[NL80211_ATTR_CQM_RSSI_HYST] = { .type = NLA_U32 },
  		[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT] = { .type = NLA_U32 },
  	};
  	struct nlattr *cqm[NL80211_ATTR_CQM_MAX + 1];
  	struct nlattr *cqm_attr = attrs[NL80211_ATTR_CQM];
  
  	printf("connection quality monitor event: ");
  
  	if (!cqm_attr ||
  	    nla_parse_nested(cqm, NL80211_ATTR_CQM_MAX, cqm_attr, cqm_policy)) {
  		printf("missing data!\n");
  		return;
  	}
  
  	if (cqm[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT]) {
  		enum nl80211_cqm_rssi_threshold_event rssi_event;
  		rssi_event = nla_get_u32(cqm[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT]);
  		if (rssi_event == NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH)
  			printf("RSSI went above threshold\n");
  		else
  			printf("RSSI went below threshold\n");
  	} else if (cqm[NL80211_ATTR_CQM_PKT_LOSS_EVENT] &&
  		   attrs[NL80211_ATTR_MAC]) {
  		uint32_t frames;
  		char buf[3*6];
  
  		frames = nla_get_u32(cqm[NL80211_ATTR_CQM_PKT_LOSS_EVENT]);
  		mac_addr_n2a(buf, nla_data(attrs[NL80211_ATTR_MAC]));
  		printf("peer %s didn't ACK %d packets\n", buf, frames);
  	} else
  		printf("unknown event\n");
  }
  
  static const char * key_type_str(enum nl80211_key_type key_type)
  {
  	static char buf[30];
  	switch (key_type) {
  	case NL80211_KEYTYPE_GROUP:
  		return "Group";
  	case NL80211_KEYTYPE_PAIRWISE:
  		return "Pairwise";
  	case NL80211_KEYTYPE_PEERKEY:
  		return "PeerKey";
  	default:
  		snprintf(buf, sizeof(buf), "unknown(%d)", key_type);
  		return buf;
  	}
  }
  
  static void parse_mic_failure(struct nlattr **attrs)
  {
  	printf("Michael MIC failure event:");
  
  	if (attrs[NL80211_ATTR_MAC]) {
  		char addr[3 * ETH_ALEN];
  		mac_addr_n2a(addr, nla_data(attrs[NL80211_ATTR_MAC]));
  		printf(" source MAC address %s", addr);
  	}
  
  	if (attrs[NL80211_ATTR_KEY_SEQ] &&
  	    nla_len(attrs[NL80211_ATTR_KEY_SEQ]) == 6) {
  		unsigned char *seq = nla_data(attrs[NL80211_ATTR_KEY_SEQ]);
  		printf(" seq=%02x%02x%02x%02x%02x%02x",
  		       seq[0], seq[1], seq[2], seq[3], seq[4], seq[5]);
  	}
  	if (attrs[NL80211_ATTR_KEY_TYPE]) {
  		enum nl80211_key_type key_type =
  			nla_get_u32(attrs[NL80211_ATTR_KEY_TYPE]);
  		printf(" Key Type %s", key_type_str(key_type));
  	}
  
  	if (attrs[NL80211_ATTR_KEY_IDX]) {
  		__u8 key_id = nla_get_u8(attrs[NL80211_ATTR_KEY_IDX]);
  		printf(" Key Id %d", key_id);
  	}
  
  	printf("\n");
  }
  
  static int print_event(struct nl_msg *msg, void *arg)
  {
  	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
  	struct nlattr *tb[NL80211_ATTR_MAX + 1], *nst;
  	struct print_event_args *args = arg;
  	char ifname[100];
  	char macbuf[6*3];
  	__u8 reg_type;
  	struct ieee80211_beacon_channel chan_before_beacon,  chan_after_beacon;
  	__u32 wiphy_idx = 0;
  	int rem_nst;
  	__u16 status;
  
  	if (args->time || args->reltime) {
  		unsigned long long usecs, previous;
  
  		previous = 1000000ULL * args->ts.tv_sec + args->ts.tv_usec;
  		gettimeofday(&args->ts, NULL);
  		usecs = 1000000ULL * args->ts.tv_sec + args->ts.tv_usec;
  		if (args->reltime) {
  			if (!args->have_ts) {
  				usecs = 0;
  				args->have_ts = true;
  			} else
  				usecs -= previous;
  		}
  		printf("%llu.%06llu: ", usecs/1000000, usecs % 1000000);
  	}
  
  	nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
  		  genlmsg_attrlen(gnlh, 0), NULL);
  
  	if (tb[NL80211_ATTR_IFINDEX] && tb[NL80211_ATTR_WIPHY]) {
  		if_indextoname(nla_get_u32(tb[NL80211_ATTR_IFINDEX]), ifname);
  		printf("%s (phy #%d): ", ifname, nla_get_u32(tb[NL80211_ATTR_WIPHY]));
  	} else if (tb[NL80211_ATTR_IFINDEX]) {
  		if_indextoname(nla_get_u32(tb[NL80211_ATTR_IFINDEX]), ifname);
  		printf("%s: ", ifname);
  	} else if (tb[NL80211_ATTR_WIPHY]) {
  		printf("phy #%d: ", nla_get_u32(tb[NL80211_ATTR_WIPHY]));
  	}
  
  	switch (gnlh->cmd) {
  	case NL80211_CMD_NEW_WIPHY:
  		printf("renamed to %s\n", nla_get_string(tb[NL80211_ATTR_WIPHY_NAME]));
  		break;
  	case NL80211_CMD_TRIGGER_SCAN:
  		printf("scan started\n");
  		break;
  	case NL80211_CMD_NEW_SCAN_RESULTS:
  		printf("scan finished:");
  	case NL80211_CMD_SCAN_ABORTED:
  		if (gnlh->cmd == NL80211_CMD_SCAN_ABORTED)
  			printf("scan aborted:");
  		if (tb[NL80211_ATTR_SCAN_FREQUENCIES]) {
  			nla_for_each_nested(nst, tb[NL80211_ATTR_SCAN_FREQUENCIES], rem_nst)
  				printf(" %d", nla_get_u32(nst));
  			printf(",");
  		}
  		if (tb[NL80211_ATTR_SCAN_SSIDS]) {
  			nla_for_each_nested(nst, tb[NL80211_ATTR_SCAN_SSIDS], rem_nst) {
  				printf(" \"");
  				print_ssid_escaped(nla_len(nst), nla_data(nst));
  				printf("\"");
  			}
  		}
  		printf("\n");
  		break;
  	case NL80211_CMD_REG_CHANGE:
  		printf("regulatory domain change: ");
  
  		reg_type = nla_get_u8(tb[NL80211_ATTR_REG_TYPE]);
  
  		switch (reg_type) {
  		case NL80211_REGDOM_TYPE_COUNTRY:
  			printf("set to %s by %s request",
  			       nla_get_string(tb[NL80211_ATTR_REG_ALPHA2]),
  			       reg_initiator_to_string(nla_get_u8(tb[NL80211_ATTR_REG_INITIATOR])));
  			if (tb[NL80211_ATTR_WIPHY])
  				printf(" on phy%d", nla_get_u32(tb[NL80211_ATTR_WIPHY]));
  			break;
  		case NL80211_REGDOM_TYPE_WORLD:
  			printf("set to world roaming by %s request",
  			       reg_initiator_to_string(nla_get_u8(tb[NL80211_ATTR_REG_INITIATOR])));
  			break;
  		case NL80211_REGDOM_TYPE_CUSTOM_WORLD:
  			printf("custom world roaming rules in place on phy%d by %s request",
  			       nla_get_u32(tb[NL80211_ATTR_WIPHY]),
  			       reg_initiator_to_string(nla_get_u32(tb[NL80211_ATTR_REG_INITIATOR])));
  			break;
  		case NL80211_REGDOM_TYPE_INTERSECTION:
  			printf("intersection used due to a request made by %s",
  			       reg_initiator_to_string(nla_get_u32(tb[NL80211_ATTR_REG_INITIATOR])));
  			if (tb[NL80211_ATTR_WIPHY])
  				printf(" on phy%d", nla_get_u32(tb[NL80211_ATTR_WIPHY]));
  			break;
  		default:
  			printf("unknown source (upgrade this utility)");
  			break;
  		}
  
  		printf("\n");
  		break;
  	case NL80211_CMD_REG_BEACON_HINT:
  
  		wiphy_idx = nla_get_u32(tb[NL80211_ATTR_WIPHY]);
  
  		memset(&chan_before_beacon, 0, sizeof(chan_before_beacon));
  		memset(&chan_after_beacon, 0, sizeof(chan_after_beacon));
  
  		if (parse_beacon_hint_chan(tb[NL80211_ATTR_FREQ_BEFORE],
  					   &chan_before_beacon))
  			break;
  		if (parse_beacon_hint_chan(tb[NL80211_ATTR_FREQ_AFTER],
  					   &chan_after_beacon))
  			break;
  
  		if (chan_before_beacon.center_freq != chan_after_beacon.center_freq)
  			break;
  
  		/* A beacon hint is sent _only_ if something _did_ change */
  		printf("beacon hint:\n");
  
  		printf("phy%d %d MHz [%d]:\n",
  		       wiphy_idx,
  		       chan_before_beacon.center_freq,
  		       ieee80211_frequency_to_channel(chan_before_beacon.center_freq));
  
  		if (chan_before_beacon.passive_scan && !chan_after_beacon.passive_scan)
  			printf("\to active scanning enabled\n");
  		if (chan_before_beacon.no_ibss && !chan_after_beacon.no_ibss)
  			printf("\to beaconing enabled\n");
  
  		break;
  	case NL80211_CMD_NEW_STATION:
  		mac_addr_n2a(macbuf, nla_data(tb[NL80211_ATTR_MAC]));
  		printf("new station %s\n", macbuf);
  		break;
  	case NL80211_CMD_JOIN_IBSS:
  		mac_addr_n2a(macbuf, nla_data(tb[NL80211_ATTR_MAC]));
  		printf("IBSS %s joined\n", macbuf);
  		break;
  	case NL80211_CMD_AUTHENTICATE:
  		printf("auth");
  		if (tb[NL80211_ATTR_FRAME])
  			print_frame(args, tb[NL80211_ATTR_FRAME]);
  		else if (tb[NL80211_ATTR_TIMED_OUT])
  			printf(": timed out");
  		else
  			printf(": unknown event");
  		printf("\n");
  		break;
  	case NL80211_CMD_ASSOCIATE:
  		printf("assoc");
  		if (tb[NL80211_ATTR_FRAME])
  			print_frame(args, tb[NL80211_ATTR_FRAME]);
  		else if (tb[NL80211_ATTR_TIMED_OUT])
  			printf(": timed out");
  		else
  			printf(": unknown event");
  		printf("\n");
  		break;
  	case NL80211_CMD_DEAUTHENTICATE:
  		printf("deauth");
  		print_frame(args, tb[NL80211_ATTR_FRAME]);
  		printf("\n");
  		break;
  	case NL80211_CMD_DISASSOCIATE:
  		printf("disassoc");
  		print_frame(args, tb[NL80211_ATTR_FRAME]);
  		printf("\n");
  		break;
  	case NL80211_CMD_UNPROT_DEAUTHENTICATE:
  		printf("unprotected deauth");
  		print_frame(args, tb[NL80211_ATTR_FRAME]);
  		printf("\n");
  		break;
  	case NL80211_CMD_UNPROT_DISASSOCIATE:
  		printf("unprotected disassoc");
  		print_frame(args, tb[NL80211_ATTR_FRAME]);
  		printf("\n");
  		break;
  	case NL80211_CMD_CONNECT:
  		status = 0;
  		if (!tb[NL80211_ATTR_STATUS_CODE])
  			printf("unknown connect status");
  		else if (nla_get_u16(tb[NL80211_ATTR_STATUS_CODE]) == 0)
  			printf("connected");
  		else {
  			status = nla_get_u16(tb[NL80211_ATTR_STATUS_CODE]);
  			printf("failed to connect");
  		}
  		if (tb[NL80211_ATTR_MAC]) {
  			mac_addr_n2a(macbuf, nla_data(tb[NL80211_ATTR_MAC]));
  			printf(" to %s", macbuf);
  		}
  		if (status)
  			printf(", status: %d: %s", status, get_status_str(status));
  		printf("\n");
  		break;
  	case NL80211_CMD_ROAM:
  		printf("roamed");
  		if (tb[NL80211_ATTR_MAC]) {
  			mac_addr_n2a(macbuf, nla_data(tb[NL80211_ATTR_MAC]));
  			printf(" to %s", macbuf);
  		}
  		printf("\n");
  		break;
  	case NL80211_CMD_DISCONNECT:
  		printf("disconnected");
  		if (tb[NL80211_ATTR_DISCONNECTED_BY_AP])
  			printf(" (by AP)");
  		else
  			printf(" (local request)");
  		if (tb[NL80211_ATTR_REASON_CODE])
  			printf(" reason: %d: %s", nla_get_u16(tb[NL80211_ATTR_REASON_CODE]),
  				get_reason_str(nla_get_u16(tb[NL80211_ATTR_REASON_CODE])));
  		printf("\n");
  		break;
  	case NL80211_CMD_REMAIN_ON_CHANNEL:
  		printf("remain on freq %d (%dms, cookie %llx)\n",
  			nla_get_u32(tb[NL80211_ATTR_WIPHY_FREQ]),
  			nla_get_u32(tb[NL80211_ATTR_DURATION]),
  			(unsigned long long)nla_get_u64(tb[NL80211_ATTR_COOKIE]));
  		break;
  	case NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL:
  		printf("done with remain on freq %d (cookie %llx)\n",
  			nla_get_u32(tb[NL80211_ATTR_WIPHY_FREQ]),
  			(unsigned long long)nla_get_u64(tb[NL80211_ATTR_COOKIE]));
  		break;
  	case NL80211_CMD_NOTIFY_CQM:
  		parse_cqm_event(tb);
  		break;
  	case NL80211_CMD_MICHAEL_MIC_FAILURE:
  		parse_mic_failure(tb);
  		break;
  	case NL80211_CMD_FRAME_TX_STATUS:
  		printf("mgmt TX status (cookie %llx): %s\n",
  			(unsigned long long)nla_get_u64(tb[NL80211_ATTR_COOKIE]),
  			tb[NL80211_ATTR_ACK] ? "acked" : "no ack");
  		break;
  	default:
  		printf("unknown event %d\n", gnlh->cmd);
  		break;
  	}
  
  	fflush(stdout);
  	return NL_SKIP;
  }
  
  struct wait_event {
  	int n_cmds;
  	const __u32 *cmds;
  	__u32 cmd;
  	struct print_event_args *pargs;
  };
  
  static int wait_event(struct nl_msg *msg, void *arg)
  {
  	struct wait_event *wait = arg;
  	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
  	int i;
  
  	for (i = 0; i < wait->n_cmds; i++) {
  		if (gnlh->cmd == wait->cmds[i]) {
  			wait->cmd = gnlh->cmd;
  			if (wait->pargs)
  				print_event(msg, wait->pargs);
  		}
  	}
  
  	return NL_SKIP;
  }
  
  int __prepare_listen_events(struct nl80211_state *state)
  {
  	int mcid, ret;
  
  	/* Configuration multicast group */
  	mcid = nl_get_multicast_id(state->nl_sock, "nl80211", "config");
  	if (mcid < 0)
  		return mcid;
  
  	ret = nl_socket_add_membership(state->nl_sock, mcid);
  	if (ret)
  		return ret;
  
  	/* Scan multicast group */
  	mcid = nl_get_multicast_id(state->nl_sock, "nl80211", "scan");
  	if (mcid >= 0) {
  		ret = nl_socket_add_membership(state->nl_sock, mcid);
  		if (ret)
  			return ret;
  	}
  
  	/* Regulatory multicast group */
  	mcid = nl_get_multicast_id(state->nl_sock, "nl80211", "regulatory");
  	if (mcid >= 0) {
  		ret = nl_socket_add_membership(state->nl_sock, mcid);
  		if (ret)
  			return ret;
  	}
  
  	/* MLME multicast group */
  	mcid = nl_get_multicast_id(state->nl_sock, "nl80211", "mlme");
  	if (mcid >= 0) {
  		ret = nl_socket_add_membership(state->nl_sock, mcid);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  __u32 __do_listen_events(struct nl80211_state *state,
  			 const int n_waits, const __u32 *waits,
  			 struct print_event_args *args)
  {
  	struct nl_cb *cb = nl_cb_alloc(iw_debug ? NL_CB_DEBUG : NL_CB_DEFAULT);
  	struct wait_event wait_ev;
  
  	if (!cb) {
  		fprintf(stderr, "failed to allocate netlink callbacks\n");
  		return -ENOMEM;
  	}
  
  	/* no sequence checking for multicast messages */
  	nl_cb_set(cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, no_seq_check, NULL);
  
  	if (n_waits && waits) {
  		wait_ev.cmds = waits;
  		wait_ev.n_cmds = n_waits;
  		wait_ev.pargs = args;
  		nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, wait_event, &wait_ev);
  	} else
  		nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_event, args);
  
  	wait_ev.cmd = 0;
  
  	while (!wait_ev.cmd)
  		nl_recvmsgs(state->nl_sock, cb);
  
  	nl_cb_put(cb);
  
  	return wait_ev.cmd;
  }
  
  __u32 listen_events(struct nl80211_state *state,
  		    const int n_waits, const __u32 *waits)
  {
  	int ret;
  
  	ret = __prepare_listen_events(state);
  	if (ret)
  		return ret;
  
  	return __do_listen_events(state, n_waits, waits, NULL);
  }
  
  static int print_events(struct nl80211_state *state,
  			struct nl_cb *cb,
  			struct nl_msg *msg,
  			int argc, char **argv)
  {
  	struct print_event_args args;
  	int ret;
  
  	memset(&args, 0, sizeof(args));
  
  	argc--;
  	argv++;
  
  	while (argc > 0) {
  		if (strcmp(argv[0], "-f") == 0)
  			args.frame = true;
  		else if (strcmp(argv[0], "-t") == 0)
  			args.time = true;
  		else if (strcmp(argv[0], "-r") == 0)
  			args.reltime = true;
  		else
  			return 1;
  		argc--;
  		argv++;
  	}
  
  	if (args.time && args.reltime)
  		return 1;
  
  	if (argc)
  		return 1;
  
  	ret = __prepare_listen_events(state);
  	if (ret)
  		return ret;
  
  	return __do_listen_events(state, 0, NULL, &args);
  }
  TOPLEVEL(event, "[-t] [-r] [-f]", 0, 0, CIB_NONE, print_events,
  	"Monitor events from the kernel.\n"
  	"-t - print timestamp\n"
  	"-r - print relative timstamp\n"
  	"-f - print full frame for auth/assoc etc.");
  