net80211 / LinuxKPI 802.11: use enum ieee80211_sta_rx_bw for ni_chw

net80211 node ni_chw currently encodes the channel width as Mhz number.
LinuxKPI 802.11 uses enum ieee80211_sta_rx_bw for the same.

Rather than keeping the "20" and "40" throughout the code (eventually
expanded to 80/160/320) switch them over to use the enum throughout
and add a print mask for debug output.  While designed as bitmask it
is not supposed to be used as such;  the bitmask is only used to be
able to use %b with a print mask.

Once we get to 320Mhz channel widths we would otherwise also need to
extend the uint8_t in struct ieee80211_node; making
enum ieee80211_sta_rx_bw __packed allows us for three more channel
widths without breaking the KBI (if we were not to use %b with a
print_mask but use a lookup function for the string we could extend
it for a long time).

Sponsored by:	The FreeBSD Foundation
MFC after:	14 days
Reviewed by:	adrian
Differential Revision: https://reviews.freebsd.org/D47891

sys/compat/linuxkpi/common/include/linux/ieee80211.h

@@ -387,14 +387,6 @@ enum ieee80211_sta_state {
 	IEEE80211_STA_AUTHORIZED	= 4,	/* 802.1x */
 };
 
-enum ieee80211_sta_rx_bw {
-	IEEE80211_STA_RX_BW_20,
-	IEEE80211_STA_RX_BW_40,
-	IEEE80211_STA_RX_BW_80,
-	IEEE80211_STA_RX_BW_160,
-	IEEE80211_STA_RX_BW_320,
-};
-
 enum ieee80211_tx_info_flags {
 	/* XXX TODO .. right shift numbers - not sure where that came from? */
 	IEEE80211_TX_CTL_AMPDU			= BIT(0),

sys/dev/ath/ath_rate/sample/sample.c

@@ -179,7 +179,7 @@ ath_rate_sample_find_min_pktlength(struct ath_softc *sc,
 	const struct txschedule *sched = &sn->sched[rix0];
 	int max_pkt_length = 65530; // ATH_AGGR_MAXSIZE
 	// Note: this may not be true in all cases; need to check?
-	int is_ht40 = (an->an_node.ni_chw == 40);
+	int is_ht40 = (an->an_node.ni_chw == IEEE80211_STA_RX_BW_40);
 	// Note: not great, but good enough..
 	int idx = is_ht40 ? MCS_HT40 : MCS_HT20;
 
@@ -973,7 +973,7 @@ update_stats(struct ath_softc *sc, struct ath_node *an,
 	const int size_bin = size_to_bin(frame_size);
 	const int size = bin_to_size(size_bin);
 	int tt;
-	int is_ht40 = (an->an_node.ni_chw == 40);
+	int is_ht40 = (an->an_node.ni_chw == IEEE80211_STA_RX_BW_40);
 	int pct;
 
 	if (!IS_RATE_DEFINED(sn, rix0))
@@ -1359,7 +1359,7 @@ ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
 				continue;
 			printf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
 			    calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
-			        (ni->ni_chw == 40)));
+			        (ni->ni_chw == IEEE80211_STA_RX_BW_40)));
 		}
 		printf("\n");
 	}
@@ -1390,7 +1390,7 @@ ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
 			
 			sn->stats[y][rix].perfect_tx_time =
 			    calc_usecs_unicast_packet(sc, size, rix, 0, 0,
-			    (ni->ni_chw == 40));
+			    (ni->ni_chw == IEEE80211_STA_RX_BW_40));
 			sn->stats[y][rix].average_tx_time =
 			    sn->stats[y][rix].perfect_tx_time;
 		}

sys/dev/ath/if_ath_tx_ht.c

@@ -283,7 +283,7 @@ ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
 		if (IS_HT_RATE(rate)) {
 			rc[i].flags |= ATH_RC_HT_FLAG;
 
-			if (ni->ni_chw == 40)
+			if (ni->ni_chw == IEEE80211_STA_RX_BW_40)
 				rc[i].flags |= ATH_RC_CW40_FLAG;
 
 			/*
@@ -295,13 +295,13 @@ ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
 			 * and doesn't return the fractional part, so
 			 * we are always "out" by some amount.
 			 */
-			if (ni->ni_chw == 40 &&
+			if (ni->ni_chw == IEEE80211_STA_RX_BW_40 &&
 			    ieee80211_ht_check_tx_shortgi_40(ni) &&
 			    (bf->bf_flags & ATH_BUF_TOA_PROBE) == 0) {
 				rc[i].flags |= ATH_RC_SGI_FLAG;
 			}
 
-			if (ni->ni_chw == 20 &&
+			if (ni->ni_chw == IEEE80211_STA_RX_BW_40 &&
 			    ieee80211_ht_check_tx_shortgi_20(ni) &&
 			    (bf->bf_flags & ATH_BUF_TOA_PROBE) == 0) {
 				rc[i].flags |= ATH_RC_SGI_FLAG;

sys/dev/mwl/if_mwl.c

@@ -4016,7 +4016,7 @@ mkpeerinfo(MWL_HAL_PEERINFO *pi, const struct ieee80211_node *ni)
 			pi->HTCapabilitiesInfo &= ~IEEE80211_HTCAP_SHORTGI40;
 		if ((vap->iv_flags_ht & IEEE80211_FHT_SHORTGI20) == 0)
 			pi->HTCapabilitiesInfo &= ~IEEE80211_HTCAP_SHORTGI20;
-		if (ni->ni_chw != 40)
+		if (ni->ni_chw != IEEE80211_STA_RX_BW_40)
 			pi->HTCapabilitiesInfo &= ~IEEE80211_HTCAP_CHWIDTH40;
 	}
 	return pi;

sys/net80211/ieee80211_ddb.c

@@ -294,8 +294,9 @@ _db_show_sta(const struct ieee80211_node *ni)
 	db_printf("\thtcap %b htparam 0x%x htctlchan %u ht2ndchan %u\n",
 		ni->ni_htcap, IEEE80211_HTCAP_BITS,
 		ni->ni_htparam, ni->ni_htctlchan, ni->ni_ht2ndchan);
-	db_printf("\thtopmode 0x%x htstbc 0x%x chw %u\n",
-		ni->ni_htopmode, ni->ni_htstbc, ni->ni_chw);
+	db_printf("\thtopmode 0x%x htstbc 0x%x chw %b\n",
+		ni->ni_htopmode, ni->ni_htstbc,
+		ni->ni_chw, IEEE80211_NI_CHW_BITS);
 
 	/* XXX ampdu state */
 	for (i = 0; i < WME_NUM_TID; i++)

sys/net80211/ieee80211_ht.c

@@ -1473,7 +1473,7 @@ ieee80211_ht_wds_init(struct ieee80211_node *ni)
 		ni->ni_htcap |= IEEE80211_HTCAP_SHORTGI20;
 	if (IEEE80211_IS_CHAN_HT40(ni->ni_chan)) {
 		ni->ni_htcap |= IEEE80211_HTCAP_CHWIDTH40;
-		ni->ni_chw = 40;
+		ni->ni_chw = IEEE80211_STA_RX_BW_40;
 		if (IEEE80211_IS_CHAN_HT40U(ni->ni_chan))
 			ni->ni_ht2ndchan = IEEE80211_HTINFO_2NDCHAN_ABOVE;
 		else if (IEEE80211_IS_CHAN_HT40D(ni->ni_chan))
@@ -1481,7 +1481,7 @@ ieee80211_ht_wds_init(struct ieee80211_node *ni)
 		if (vap->iv_flags_ht & IEEE80211_FHT_SHORTGI40)
 			ni->ni_htcap |= IEEE80211_HTCAP_SHORTGI40;
 	} else {
-		ni->ni_chw = 20;
+		ni->ni_chw = IEEE80211_STA_RX_BW_20;
 		ni->ni_ht2ndchan = IEEE80211_HTINFO_2NDCHAN_NONE;
 	}
 	ni->ni_htctlchan = ni->ni_chan->ic_ieee;
@@ -1577,7 +1577,7 @@ ieee80211_ht_node_join(struct ieee80211_node *ni)
 
 	if (ni->ni_flags & IEEE80211_NODE_HT) {
 		vap->iv_ht_sta_assoc++;
-		if (ni->ni_chw == 40)
+		if (ni->ni_chw == IEEE80211_STA_RX_BW_40)
 			vap->iv_ht40_sta_assoc++;
 	}
 	htinfo_update(vap);
@@ -1595,7 +1595,7 @@ ieee80211_ht_node_leave(struct ieee80211_node *ni)
 
 	if (ni->ni_flags & IEEE80211_NODE_HT) {
 		vap->iv_ht_sta_assoc--;
-		if (ni->ni_chw == 40)
+		if (ni->ni_chw == IEEE80211_STA_RX_BW_40)
 			vap->iv_ht40_sta_assoc--;
 	}
 	htinfo_update(vap);
@@ -1823,7 +1823,8 @@ htinfo_update_chw(struct ieee80211_node *ni, int htflags, int vhtflags)
 
 done:
 	/* update node's (11n) tx channel width */
-	ni->ni_chw = IEEE80211_IS_CHAN_HT40(ni->ni_chan)? 40 : 20;
+	ni->ni_chw = IEEE80211_IS_CHAN_HT40(ni->ni_chan) ?
+	    IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;
 	return (ret);
 }
 
@@ -2599,11 +2600,12 @@ ht_recv_action_ht_txchwidth(struct ieee80211_node *ni,
 {
 	int chw;
 
-	chw = (frm[2] == IEEE80211_A_HT_TXCHWIDTH_2040) ? 40 : 20;
+	chw = (frm[2] == IEEE80211_A_HT_TXCHWIDTH_2040) ?
+	    IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;
 
 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_ACTION | IEEE80211_MSG_11N, ni,
-	    "%s: HT txchwidth, width %d%s",
-	    __func__, chw, ni->ni_chw != chw ? "*" : "");
+	    "%s: HT txchwidth, width %b%s",
+	    __func__, chw, IEEE80211_NI_CHW_BITS, ni->ni_chw != chw ? "*" : "");
 	if (chw != ni->ni_chw) {
 		/* XXX does this need to change the ht40 station count? */
 		ni->ni_chw = chw;
@@ -3742,5 +3744,5 @@ ieee80211_ht_check_tx_ht40(const struct ieee80211_node *ni)
 
 	return (IEEE80211_IS_CHAN_HT40(bss_chan) &&
 	    IEEE80211_IS_CHAN_HT40(ni->ni_chan) &&
-	    (ni->ni_chw == 40));
+	    (ni->ni_chw == IEEE80211_STA_RX_BW_40));
 }

sys/net80211/ieee80211_node.c

@@ -2672,8 +2672,9 @@ ieee80211_dump_node(struct ieee80211_node_table *nt __unused,
 	printf("\thtcap %x htparam %x htctlchan %u ht2ndchan %u\n",
 		ni->ni_htcap, ni->ni_htparam,
 		ni->ni_htctlchan, ni->ni_ht2ndchan);
-	printf("\thtopmode %x htstbc %x htchw %u\n",
-		ni->ni_htopmode, ni->ni_htstbc, ni->ni_chw);
+	printf("\thtopmode %x htstbc %x htchw %b\n",
+		ni->ni_htopmode, ni->ni_htstbc,
+		ni->ni_chw, IEEE80211_NI_CHW_BITS);
 	printf("\tvhtcap %x freq1 %d freq2 %d vhtbasicmcs %x\n",
 		ni->ni_vhtcap, (int) ni->ni_vht_chan1, (int) ni->ni_vht_chan2,
 		(int) ni->ni_vht_basicmcs);
@@ -2831,7 +2832,7 @@ ieee80211_node_join(struct ieee80211_node *ni, int resp)
 	    ni->ni_flags & IEEE80211_NODE_QOS ? ", QoS" : "",
 	    /* XXX update for VHT string */
 	    ni->ni_flags & IEEE80211_NODE_HT ?
-		(ni->ni_chw == 40 ? ", HT40" : ", HT20") : "",
+		(ni->ni_chw == IEEE80211_STA_RX_BW_40 ? ", HT40" : ", HT20") : "",
 	    ni->ni_flags & IEEE80211_NODE_AMPDU ? " (+AMPDU)" : "",
 	    ni->ni_flags & IEEE80211_NODE_AMSDU ? " (+AMSDU)" : "",
 	    ni->ni_flags & IEEE80211_NODE_MIMO_RTS ? " (+SMPS-DYN)" :

sys/net80211/ieee80211_node.h

@@ -108,6 +108,25 @@ enum ieee80211_mesh_mlstate {
 #define	IEEE80211_MESH_MLSTATE_BITS \
 	"\20\1IDLE\2OPENSNT\2OPENRCV\3CONFIRMRCV\4ESTABLISHED\5HOLDING"
 
+/*
+ * This structure is shared with LinuxKPI 802.11 code describing up-to
+ * which channel width the station can receive.
+ * Rather than using hardcoded MHz values for the channel width use an enum with
+ * flags. This allows us to keep the uint8_t slot for ni_chw in
+ * struct ieee80211_node and means we do not have to sync to the value for
+ * LinuxKPI.
+ */
+enum ieee80211_sta_rx_bw {
+	IEEE80211_STA_RX_BW_20		= 0x01,
+	IEEE80211_STA_RX_BW_40		= 0x02,
+	IEEE80211_STA_RX_BW_80		= 0x04,
+	IEEE80211_STA_RX_BW_160		= 0x08,
+	IEEE80211_STA_RX_BW_320		= 0x10,
+} __packed;
+
+#define	IEEE80211_NI_CHW_BITS \
+	"\20\1BW_20\2BW_40\3BW_80\4BW_160\5BW_320"
+
 /*
  * Node specific information.  Note that drivers are expected
  * to derive from this structure to add device-specific per-node
@@ -222,7 +241,7 @@ struct ieee80211_node {
 	uint8_t			ni_ht2ndchan;	/* HT 2nd channel */
 	uint8_t			ni_htopmode;	/* HT operating mode */
 	uint8_t			ni_htstbc;	/* HT */
-	uint8_t			ni_chw;		/* negotiated channel width */
+	enum ieee80211_sta_rx_bw ni_chw;	/* negotiated channel width */
 	struct ieee80211_htrateset ni_htrates;	/* negotiated ht rate set */
 	struct ieee80211_tx_ampdu ni_tx_ampdu[WME_NUM_TID];
 	struct ieee80211_rx_ampdu ni_rx_ampdu[WME_NUM_TID];

sys/net80211/ieee80211_sta.c

@@ -1937,7 +1937,7 @@ sta_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m0, int subtype,
 		    vap->iv_flags&IEEE80211_F_USEPROT ? ", protection" : "",
 		    ni->ni_flags & IEEE80211_NODE_QOS ? ", QoS" : "",
 		    ni->ni_flags & IEEE80211_NODE_HT ?
-			(ni->ni_chw == 40 ? ", HT40" : ", HT20") : "",
+			(ni->ni_chw == IEEE80211_STA_RX_BW_40 ? ", HT40" : ", HT20") : "",
 		    ni->ni_flags & IEEE80211_NODE_AMPDU ? " (+AMPDU)" : "",
 		    ni->ni_flags & IEEE80211_NODE_AMSDU ? " (+AMSDU)" : "",
 		    ni->ni_flags & IEEE80211_NODE_MIMO_RTS ? " (+SMPS-DYN)" :